Studies on gelatin-containing artificial skin: II. Preparation and characterization of cross-linked gelatin-hyaluronate sponge

This study was conducted to develop a new sponge type of biomaterial to be used for either wound dressing or scaffold for tissue engineering. We were able to prepare an insoluble matrix composed of gelatin and sodium hyaluronate (HA) by dipping the soluble sponge into 90% (w/v) acetone/water mixture containing a small amount of cross-linking agent, 1-ethyl-3-3-dimethylaminoproplycarbodiimide hydrochloride, EDC. To characterize the sponge, Fourier-transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and Instron analysis were performed. The obtained results indicate that the chemically cross-linked sponge shows a cross-linking degree of 10-35%, a mean pore size of 40-160 microm, porosity of 35-67%, and a tensile strength of 10-30 gf/cm(2). Especially, the porosity measured by image analysis showed a tendency to increase with HA content, resulting in an increased water uptake. The resistance to collagenase degradation in vitro increased for up to 2 days. Silver sulfadiazine (AgSD)-impregnated gelatin-HA sponge was also prepared and compared with conventional vaseline gauze by applying it onto a dorsal skin defect of wistar rat for 5, 12, and 21 days. Histological results showed an enhancement of wound healing in AgSD-impregnated gelatin-HA sponge.

Changes in corneal epithelial barrier function after excimer laser photorefractive keratectomy

PURPOSE

To use fluorophotometry to measure corneal epithelial barrier function after excimer laser photorefractive keratectomy (PRK).

SETTING

Seoul National University Hospital, Seoul, Korea.

METHODS

Twenty-five eyes of 21 patients (13 women, 8 men) had PRK to correct myopia. Corneal epithelial healing time was measured and corneal epithelial permeability to sodium fluorescein evaluated by fluorophotometry 1, 2, and 3 weeks after surgery.

RESULTS

Epithelial permeability showed a statistically significant increase 1 week after surgery and returned to its preoperative level 1 week later. Comparative studies according to epithelial healing day and corrected diopter showed results that were not statistically significant (P > .05).

CONCLUSION

These results suggest that PRK delays complete reconstruction of corneal epithelial barrier function. In humans, the corneal epithelium regained its normal barrier function 2 weeks after PRK. Thus, at least during these weeks, care should be taken to minimize further epithelial trauma.

Restoration of atrial mechanical function after maze operation in patients with structural heart disease

BACKGROUND

The maze operation is effective for the restoration of sinus rhythm; however, restoration of atrial mechanical function has not been demonstrated in all patients.

METHODS

Maze operations were performed in 32 patients (13 men, 19 women; mean age 47.1 +/- 9.0 years) combined with valvular surgery (n = 25), coronary artery bypass graft (CABG) (n = 3), and others (n = 4). At 1 week, 3 months, 6 months, and 1 year after the operation, prospective serial Doppler echocardiographic examination was carried out to determine the presence of atrial mechanical function.

RESULTS

Sinus rhythm was restored and maintained during the follow-up period in 26 (81%) patients; in 22 patients this was due solely to the operation, whereas in four patients an antiarrhythmic agent was needed to maintain sinus rhythm. Another four patients showed paroxysmal atrial fibrillation (AF) despite treatment with an antiarrhythmic agent. Right atrial mechanical function was restored in all 30 patients with sinus rhythm or paroxysmal AF; in 19 (63%) of these, left atrial mechanical function was restored. In patients with restored left atrial mechanical function, peak A velocity (A) and A/E ratio (A/E) of mitral inflow were significantly lower than in the 16 postoperative control patients (A: 0.46 +/- 0.14 m/sec vs 0. 75 +/- 0.29 m/sec, p < 0.01; A/E: 0.40 vs 0.80, p < 0.01). In patients with left atrial mechanical function, the duration of AF was significantly shorter than in patients without left atrial mechanical function (1.9 +/- 2.9 years vs 7.1 +/- 3.0 years, p < 0. 01), but there were no significant differences in left atrial size and volume.

CONCLUSIONS

The maze operation could be safely added to standard open heart surgery for the correction of underlying structural heart disease. The rate of conversion to sinus rhythm resulting solely from the operation might be lower than the rates previously reported with only the duration of AF adversely affecting the restoration of left atrial mechanical function. Considering the fact that not all patients converted to sinus rhythm show atrial mechanical function, the role of the maze operation in the prevention of systemic embolism, with subsequent improvement in survival, requires further study.

Effect of red ginseng on blood pressure in patients with essential hypertension and white coat hypertension

The objective of this study is to evaluate the changes of diurnal blood pressure pattern after 8 weeks of red ginseng medication (4.5 g/day) by 24 hour ambulatory blood pressure monitoring. In 26 subjects with essential hypertension, 24 hour mean systolic blood pressure decreased significantly (p = 0.03) while diastolic blood pressure only showed a tendency of decline (p = 0.17). The decrease in pressures were observed at daytime (8 A.M.-6 P.M.) and dawn (5 A.M.-7 A.M.). In 8 subjects with white coat hypertension, no significant blood pressure change was observed. We suggest that red ginseng might be useful as a relatively safe medication adjuvant to current antihypertensive medications.

Granulocyte macrophage colony-stimulating factor is the main cytokine enhancing survival of eosinophils in asthmatic airways

Interleukin (IL)-3, IL-5 and granulocyte macrophage colony-stimulating factor (GM-CSF) prolong the survival of eosinophils, which are conspicuous in asthmatic airways, but it is still controversial which one plays a major role in enhancing the survival of eosinophils in asthmatic airways. The role of these cytokines in airway eosinophilia was investigated using bronchoalveolar lavage (BAL) fluids from 11 symptomatic and nine asymptomatic patients with asthma and eight normal subjects. Eosinophil survival-enhancing activity (ESEA) was measured by a numerical change in viable eosinophils isolated from the peripheral blood of atopic patients and cultured with BAL fluids. ESEA was characterized by neutralization with antibodies to IL-3, IL-5 and/or GM-CSF. The differential count of BAL cells was achieved using Diff-Quik stain. T-cell subsets and activated T-cells were analysed by flow cytometry with dual stain using monoclonal antibodies to CD3, CD4, CD8 and CD25. ESEA was detected in eight of 11 BAL fluids of symptomatic asthma, but not in those of normal controls or asymptomatic asthmatics. In six symptomatic asthmatics, the mean percentage of inhibition in ESEA by anti-GM-CSF was higher than that of anti-IL-5 as well as anti-IL-3 (p<0.05). A mixture of antibodies to IL-3, IL-5 and GM-CSF totally inhibited the ESEA in four cases. The ESEA correlated with the percentage of eosinophils (p<0.05) and that of CD25(+)CD4 lymphocytes (p<0.05) of BAL cells. In conclusion, granulocyte macrophage colony-stimulating factor, rather than interleukin-3 or -5, is associated with eosinophil survival-enhancing activity inside the airways of symptomatic asthmatics. The activation of CD4 lymphocytes is related to the elevation of such activity.

Effects of soluble dietary fibers on lipid metabolism and activities of intestinal disaccharidases in rats

The present study was aimed to investigate the effects of indigestible dextrin and polydextrose, soluble dietary fibers with low molecular weight, on lipid metabolism and disaccharidase activities of intestinal mucosa in rats fed a high sucrose diet. Their effects were compared with those of well-known soluble fibers, pectin, and guar gum, and also with an insoluble fiber, cellulose. Dietary fibers added to diets at the 5% (w/w) level were alpha-cellulose, pectin, guar gum, indigestible dextrin, and polydextrose. Male Sprague-Dawley rats were given free access to test diets for 6 weeks. Body weight gain was the lowest in rats fed guar gum, the highest in rats fed cellulose, and in-between in rats fed other diets. Although guar gum, pectin, and indigestible feeding dextrin had lower plasma lipid values than cellulose feeding did, the differences were statistically insignificant. Liver triglyceride of the guar gum-fed group was about a third that of the cellulose-fed group, but although those of rats fed polydextrose, indigestible dextrin, and pectin were lower than that of cellulose, the differences were insignificant. Liver cholesterol and phospholipid concentrations were similar among groups. Daily fecal excretion of total lipid, cholesterol, and bile acids were highest in rats fed guar gum, followed by pectin-fed and cellulose-fed rats, and the lowest in rats fed indigestible dextrin and polydextrose. Jejunal sucrase activity was low in the order of guar-gum, polydextrose, indigestible dextrin, pectin, and cellulose. The results indicate that the hypolipidemic effect of soluble dietary fibers would be lessened with reduction in molecular weight, but that the lower sucrase activity by soluble fibers with low molecular weight might be beneficial for hypoglycemic effect.

Computer analysis of human depth EEG in different sleep stages

This study compares delta (< 4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (12-20 Hz) band EEG signals during wakefulness, rapid-eye-movement (REM) sleep, and stage 1 and stage 2 non-REM sleep recorded from both surface and depth electrodes in patients with drug-resistant partial seizures. Computer analysis utilizing Fast Fourier Transforms (FFT) was performed with the Neurovision software developed for this purpose. Mean amplitudes were calculated for each of the frequency bands. Preliminary analysis was performed with emphasis on the presence and characteristics of theta activity in the hippocampus of the brain. Results demonstrate theta wave activity in the hippocampus with an increase of theta activity in REM sleep as compared to non-REM sleep (stages 1 and 2).

Plasma membrane steroidogenic cholesterol: the relative importance of membrane internalization rate and cholesterol extraction rate of internalized membrane

Most cholesterol destined to become steroid hormone passes through the plasma membrane. Using MA-10 Leydig tumor cells as a model system, we determined that plasma membrane cholesterol disappeared 2.5-fold faster in cAMP-stimulated cells. Stimulation of MA-10 cells increased internalization so that 1.4-fold more membrane cycled through the cell per unit time. Increased internalization accounted for 26% of the cholesterol actually lost from cycling membrane. The remaining 74% was accounted for by increasing the extraction of cholesterol from internalized membrane.

Effect of the application of human amniotic membrane on rabbit corneal wound healing after excimer laser photorefractive keratectomy

PURPOSE

We investigated the influence of amniotic membrane application on corneal wound healing after excimer laser photorefractive keratectomy (PRK) in rabbits.

METHODS

PRK of -9.9 D with an optical zone of 5.0 mm was performed on each right eye of 34 pigmented rabbits, which had been divided into two groups. In 17 eyes, preserved human amniotic membrane was applied in such a way that it covered the entire cornea for 48 h (amniotic group), and the other eyes formed the control group. The area of epithelial defect, inflammatory cell infiltration, the number of anterior stromal keratocytes, and corneal haze were evaluated.

RESULTS

In all animals, the epithelium had healed completely within 3 days, and there was no difference between the two groups. At postoperative 12 and 24 h, the numbers of stromal inflammatory cells in the amniotic group were significantly lower than those in the control group (p = 0.009), and the numbers of anterior stromal keratocytes were significantly higher (p < 0.05). At postoperative weeks 2, 4, 6, 8, and 12, corneal haze scores in the amniotic group were lower than those in the control group (p < 0.05), and at postoperative week 12, the number of anterior stromal keratocytes in the amniotic group was significantly lower than that in the control group (p = 0.002).

CONCLUSION

The application of amniotic membrane after PRK reduces keratocyte proliferation and corneal haze during corneal wound healing, possibly by reducing the infiltration of inflammatory cells and loss of keratocytes in the ablation area during the early postoperative period.

Anemia and red cell distribution width at the 12-month well-baby examination

BACKGROUND

Screens for anemia are among the most commonly done laboratory tests in children. The red cell distribution width (RDW) has been proposed as a diagnostic aid in the evaluation of pediatric anemias, but no prospective studies have been published describing its use.

METHODS

A screening hematocrit determination done at the 12-month well-baby examination in 970 healthy infants yielded 62 low values (< 33%), 31 of which were confirmed by heel stick complete blood count (CBC). After a 1-month trial of iron therapy, those with a rise in hemoglobin of at least 1 g/dL were considered to have iron-deficiency anemia. Nonresponders, after review of clinical and laboratory data (CBC, lead screen, and sickle screen), had hemoglobin electrophoresis if indicated.

RESULTS

Abnormalities detected were iron deficiency, alpha-thalassemia, and hemoglobins SC and AS. These conditions were detected in 9 of 11 infants with abnormal RDW and none of 9 with normal RDW.

CONCLUSIONS

The RDW alone appears to be predictive of identifiable causes of anemia when used in screening 12-month-old babies who are otherwise healthy.

IL-10 interrupts memory B cell expansion in the germinal center by inducing differentiation into plasma cells

Germinal center (GC) B cells undergo proliferation, somatic hypermutation and isotype switching in the course of differentiation into plasma cells to produce high-affinity antibodies. To understand the molecular mechanism regulating the expansion of memory B cells and the termination of expansion by differentiation into plasma cells, we investigated the effect of interleukin-2 (IL-2), IL-4, IL-10 and CD40 ligand (CD40L) on the differentiation of GC B cells in the defined culture system containing a follicular dendritic cell (FDC)-like cell line. IL-2, IL-4 and CD40L are required for the optimum proliferation and differentiation of GC B cells. When IL-10 was added to this culture condition, CD20+ CD38+ GC B cells sequentially differentiated into CD20+ CD38- memory B cells and then CD20- CD38+ plasma cells. In the absence of IL-10, the resulting CD20+ CD38- memory B cells continued to proliferate and retained its phenotype. The proliferation of memory B cells was interrupted by addition of IL-10 which induced the differentiation into plasma cells. The expression of CD80 and CD86 was up-regulated in the memory B cells, compared to naive B cells and plasma cells. The identity of memory B cells generated in vitro from GC B cells was further substantiated since memory B cells generated in vivo displayed the identical pattern of proliferation and differentiation under the same culture condition. These results highlight the potent role of GCT helper cells in the expansion and differentiation of memory B cells by regulating different cytokine production.

Reciprocal change in angiotensinogen mRNA expression in rat myocardium and liver after myocardial infarction

The aim of this study was to analyze sequential change of angiotensinogen (Ao) mRNA expression in rat liver and noninfarcted myocardium after myocardial infarction (MI). Female sprague-Dawley rats were subjected either to left coronary artery occlusion or sham operation. Three weeks after MI, coronary artery ligation resulted in comparable infarct sizes. A hypokinetic thin anterior wall and remarkable dilatation of the left ventricle, as well as decreased contractility (left ventricular end-systolic dimension = 6.0+/-0.4, 3.3+/-0.2, LV end-diastolic dimension = 7.9+/-0.3, 5.9+/-0.2 mm, and fractional shortening = 25.3+/-3.1%, 45.1+/-3.3%) were shown in the MI and sham group, respectively, by echocardiography (P < 0.01). Experimental MI caused a significant fall in systolic blood pressure (MI 90+/-5.0, vs sham 130+/-7.5 mmHg; P< 0.01) and significantly higher left ventricular end-diastolic pressure (MI 21+/-1.5, vs sham 11+/-1.0 mmHg: P < 0.01). At 4, 18, and 24h after MI, liver Ao mRNA levels, as shown by Northern blot analysis, had increased by up to four times (Ao/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) = 1.4+/-0.1 and 6.0+/-0.2 at baseline and 4h after MI, respectively (P < 0.01). After sham surgery, however, the corresponding increase was slight (maximal 1.5-fold). Three days after MI, liver mRNA had returned to the baseline level. In contrast, ATG mRNA expression in noninfarcted myocardium, as shown by reverse transcription-polymerase chain reaction and Southern blotting, decreased transiently during the acute phase. It returned to its baseline level within 3 days, and then increased further (Ao/ GAPDH = 2.9+/-0.6, 0.3+/-0.1, 3.2+/-0.8, and 3.7+/-0.8 at baseline, 24h, 3 days, and 3 weeks after MI, respectively). In conclusion, it can be stated that after MI, the Ao gene contributes, acutely in the liver and chronically in the myocardium, to the maintenance of hemodynamic homeostasis during the acute phase and ventricular remodeling during the chronic phase.

Identification and activation mechanism of the interleukin-4-induced nuclear factor binding to the CD23(b) promoter in human B lymphocytes

CD23 is a B cell activation antigen involved in B cell proliferation and production of IgE, of which two isoforms are known. While CD23(a) is constitutively expressed in B cells, the expression of CD23(b) is specifically induced by interleukin-4 (IL-4) or selected mitogenic stimuli. We have previously shown that CD23(b) is a primary response gene rapidly activated by IL-4 in resting human B cells. We now report the identification of a nuclear factor binding to the IL-4-response element (IL-4RE) in CD23(b) promoter in purified human tonsillar B cells. Activation of this factor, named NF-IL-4/CD23, occurred within 5 min after IL-4 treatment in a cycloheximide-insensitive manner. The activation was sensitive to phosphatases and inhibitors of protein tyrosine kinases, but it was not sensitive to inhibitors of protein kinase C. This behavior, in fact, closely correlates with the IL-4-induced activation mechanism of CD23 gene expression. In transformed B cell line Raji, where the IL-4-induced CD23 mRNA expression was hardly detected, no activation of NF-IL-4/CD23 was noted. The activation was also observed that although a sequence highly homologous to the IL-4RE of the CD23(b) promoter is present in the CD23(a) promoter, the IL-4-induced factor did not bind the sequence. These results strongly suggest that NF-IL-4/CD23 acts as an IL-4 signal transducer leading to CD23(b) gene activation in human B cells. Further characterization of this factor is now in progress, including comparison with STAT6, recently shown to be involved in IL-4 signal transduction and transcriptional activation.

The functional role of B cell antigen receptor stimulation and IL-4 in the generation of human memory B cells from germinal center B cells

The germinal center (GC) is an anatomical site where memory B cells are generated. Ag-Ab complexes presented by follicular dendritic cells in GC select precursors of memory B cells. Using a unique in vitro experimental system in which the survival of GC B cells is supported by a defined follicular dendritic cell-like cell line, we investigated the effects of B cell Ag receptor (BCR) stimulation and IL-4 on the memory B cell generation from centroblasts. IL-4 is reported to be critical for GC formation. Centroblasts differentiated to centrocytes during the culture period of 3 days as demonstrated by the down-regulation of CD77 expression and induction of CD44 as well as Bcl-2 expression. The transition of centroblast to centrocyte was enhanced by BCR stimulation and IL-4. Upon further culture, the centrocytes differentiated to memory B cells, a process that was enhanced by BCR stimulation and IL-4. The presence of IL-4 in the culture did not increase the number of plasma cells. These experimental data provide formal in vitro evidence that Ags in GC may participate not only in the selection but also in the expansion of memory B cells and that IL-4 is a growth factor promoting this expansion.

The functional role of B cell antigen receptor stimulation and IL-4 in the generation of human memory B cells from germinal center B cells

The germinal center (GC) is an anatomical site where memory B cells are generated. Ag-Ab complexes presented by follicular dendritic cells in GC select precursors of memory B cells. Using a unique in vitro experimental system in which the survival of GC B cells is supported by a defined follicular dendritic cell-like cell line, we investigated the effects of B cell Ag receptor (BCR) stimulation and IL-4 on the memory B cell generation from centroblasts. IL-4 is reported to be critical for GC formation. Centroblasts differentiated to centrocytes during the culture period of 3 days as demonstrated by the down-regulation of CD77 expression and induction of CD44 as well as Bcl-2 expression. The transition of centroblast to centrocyte was enhanced by BCR stimulation and IL-4. Upon further culture, the centrocytes differentiated to memory B cells, a process that was enhanced by BCR stimulation and IL-4. The presence of IL-4 in the culture did not increase the number of plasma cells. These experimental data provide formal in vitro evidence that Ags in GC may participate not only in the selection but also in the expansion of memory B cells and that IL-4 is a growth factor promoting this expansion.

[Infection status with trematode metacercariae in the fresh-water fish from Chunamchosuchi (pond), Uichang-gun, Kyongsangnam-do, Korea]

The present study was performed to analyze the infection status of trematode metacercariae in fishes caught from Chunamchosuchi (pond) located in Uichang-gun, Kyongsangnam-do. A total of 130 freshwater fish of 5 species was collected by a fish net and fish traps from November, 1995 to May, 1996. They were examined under a stereomicroscope after artificial digestion with pepsin-HCl solution. A total of 8 species of metacercaria, i.e. Clonorchis sinensis, Echinochasmus japonicus, Cyathocotyle orientalis, Diplostomum sp., Metorchis orientalis, Holostephanus nipponicus, Exorchis oviformis and unidentified echinostome, was detected from them. The metacercariae of C. sinenesis were found in 8/20 (40.0%) Acanthorhodeus asmussi, 20/20 (100%) Culter brevicauda, 31/45 (68.9) Cultriculus eigenmanni and 21/25 (84.0%) Pseudorasbora parva, and the average number of metacercariae detected in each fish species were 1.9, 31.7, 15.3, and 73.0. From the above results, it was confirmed that fresh-water fishes from Chunamchosuchi (pond) were highly infected with metacercariae of avian trematode, i.e. C. orientalis, H. nipponicus, M. orientalis, E. japonicus and Diplostomum sp., and 4 species of fish, P. parva, C. brevicauda, C. eigenmanni and A. asmussi, were infected with metacaecariae of C. sinensis.

Assessment of mitral annulus velocity by Doppler tissue imaging in the evaluation of left ventricular diastolic function

OBJECTIVES

This study assessed the clinical utility of mitral annulus velocity in the evaluation of left ventricular diastolic function.

BACKGROUND

Mitral inflow velocity recorded by Doppler echocardiography has been widely used to evaluate left ventricular diastolic function but is affected by other factors. The mitral annulus velocity profile during diastole may provide additional information about left ventricular diastolic function.

METHODS

Mitral annulus velocity during diastole was measured by Doppler tissue imaging (DTI) 1) in 59 normal volunteers (group 1); 2) in 20 patients with a relaxation abnormality as assessed by Doppler mitral inflow variables (group 2) at baseline and after saline loading; 3) in 11 patients (group 3) with normal diastolic function before and after intravenous nitroglycerin infusion; and 4) in 38 consecutive patients (group 4) undergoing cardiac catheterization in whom mitral inflow velocity and tau as well as mitral annulus velocity were measured simultaneously.

RESULTS

In group 1, mean +/- SD peak early and late diastolic mitral annulus velocity was 10.0 +/- 1.3 and 9.5 +/- 1.5 cm/s, respectively. In group 2, mitral inflow velocity profile changed toward the pseudonormalization pattern with saline loading (deceleration time 311 +/- 84 ms before to 216 +/- 40 ms after intervention, p < 0.001), whereas peak early diastolic mitral annulus velocity did not change significantly (5.3 +/- 1.2 cm/s to 5.7 +/- 1.4 cm/s, p = NS). In group 3, despite a significant change in mitral inflow velocity profile after nitroglycerin, peak early diastolic mitral annulus velocity did not change significantly (9.5 +/- 2.2 cm/s to 9.2 +/- 1.7 cm/s, p = NS). In group 4, peak early diastolic mitral annulus velocity (r = -0.56, p < 0.01) and the early/late ratio (r = -0.46, p < 0.01) correlated with tau. When the combination of normal mitral inflow variables with prolonged tau (> or = 50 ms) was classified as pseudonormalization, peak early diastolic mitral annulus velocity < 8.5 cm/s and the early/late ratio < 1 could identify the pseudonormalization with a sensitivity of 88% and specificity of 67%.

CONCLUSIONS

Mitral annulus velocity determined by DTI is a relatively preload-independent variable in evaluating diastolic function.

Bacterial keratitis after photoreactive keratectomy in a young, healthy man

A 34-year-old man who had excimer laser photorefractive keratectomy (PRK) for myopia developed bacterial keratitis from Pseudomonas aeruginosa. He was treated with intensive topical and systemic antimicrobial agents. The eye recovered an uncorrected visual acuity of 20/30. Bacterial keratitis can occur in young, healthy patients after PRK, especially when a bandage soft contact lens is used without appropriate prophylactic measures.

Temperature-guided radiofrequency catheter ablation of accessory pathway

OBJECTIVES

This study was performed to evaluate the usefulness of temperature-guided radiofrequency catheter ablation for the elimination of accessory pathway conduction in patients with Wolff-Parkinson-White syndrome.

METHODS

Temperature-guided radiofrequency catheter ablation was attempted in 138 patients with 144 accessory pathways (88 pathways along the left free wall, 5 in the anteroseptal region, 2 in the midseptal region, 19 in the posteroseptal region and 30 along the right free wall). The energy source was a HAT 200S which regulated the power automatically to the set temperature of 70 degrees C. Radiofrequency current was delivered through a thermocatheter to the atrial or ventricular side of mitral or tricuspid annulus.

RESULTS

Accessory pathway conduction was eliminated in 130 of 144 pathways (90.3%). The mean power outputs of the successful ablations at the atrial side of the annulus were higher than those at the ventricular side (34.0 +/- 8.9W versus 20.0 +/- 7.6W, p < 0.01), but the maximum temperatures were lower at the atrial side of the annulus than those at the ventricular side (66.4 +/- 14.0 degrees C versus 77.2 +/- 6.4 degrees C, p < 0.01). There were 3 non-fatal complications (2.1%), 2 patients with hemopericardium and 1 with femoral artery thrombus, during or after ablation procedures. Recurrences of AV re-entrant tachycardia or delta wave on the electrocardiogram occurred in 4 patients (2.8%) who had successful second procedures. There were no late complications during a mean follow-up period of 41 +/- 25 months (range, 3 to 55).

CONCLUSION

We conclude that 1) temperature-guided radiofrequency catheter ablation can be performed reliably and safely in eliminating accessory pathway conduction in patients with WPW syndrome, and 2) temperature monitoring and adjustment of the power to the set temperature during ablation would be useful for the avoidance of impedance rises and coagulum formation.

The apoptosis and proliferation of SAC-activated B cells by IL-10 are associated with changes in Bcl-2, Bcl-xL, and Mcl-1 expression

Interleukin-10 (IL-10), a cytokine from mouse Th2 cells and macrophage that inhibits IL-2 and IFN-gamma production by Th1 cells, has been reported to stimulate growth and differentiation of B cells activated by CD40 or antigen receptor crosslinking. Our early observation revealed that IL-10 had B cell growth factor (BCGF) activity in human B cells preactivated with SAC or anti-Ig. The responsiveness of the preactivated B cells to IL-10 greatly increased when B cells were activated in the presence of IL-2, whereas IL-10 has no BCGF activity when added at the initiation of activation by SAC. To investigate the dual effects (proliferation and apoptosis) of IL-10 on B cells, the expression of a panel of bcl-2 protoncogene family members, bcl-2, bcl-x, mcl-1, and bax, was analyzed when B cells were activated by SAC. Bcl-xL protein was not expressed in the small resting B cells but was induced by SAC stimulation, reaching its peak at 48 hr. The addition of IL-2 further augmented the Bcl-xL expression with the same kinetics, whereas Bcl-2 and Mcl-1 were expressed by resting B cells and enhanced by SAC stimulation. However, the addition of IL-10 at the initiation of activation down-regulated Bcl-xL, Bcl-2, and Mcl-1 expression. At the same time, B cell proliferation was inhibited and apoptotic cell number increased, suggesting the growth arrest and/or apoptosis of B cells. The apoptosis of SAC-activated B cells by IL-10 was further confirmed by propidium iodide-staining and Annexin V-FITC-staining methods. In contrast, IL-10 failed to down-regulate the Bcl-xL and Bcl-2 expression but rather augmented the expression of Mcl-1 of B cells after preactivation for 48 hr with SAC and IL-2. Under this culture condition, B cells responded to IL-10 to proliferate and differentiate, while IL-2 and IL-10 had an additive or synergistic effect. Taken together, our data suggest that IL-10 acts on the induction stage of Bcl-xL expression and regulates the apoptosis and proliferation of SAC-activated B cells through their bcl-2 family gene expression.

Keratitis from corneal anesthetic abuse after photorefractive keratectomy

After having photorefractive keratectomy (PRK), a 29-year-old man suffered from delayed epithelial healing and corneal stromal ring infiltrates. All laboratory results including smear, culture, and biopsy for bacteria, herpes simplex virus, and Acanthamoeba were negative. The suspected cause was patient abuse of anesthetics. Subsequently, it was discovered that for 6 months, since just after the PRK, the patient had intermittently used topical proparacaine drops. After all medication was discontinued and the eye pressure patched, the corneal epithelium healed completely. Practitioners should consider the possibility of topical anesthetic abuse in cases of keratitis after PRK.

MR of childhood metachromatic leukodystrophy

PURPOSE

To investigate the MR findings of childhood metachromatic leukodystrophy (MLD).

METHODS

Nine MR imaging studies in seven children (five girls and two boys, 10 to 32 months old) with MLD were evaluated retrospectively for the extent and progression of white matter abnormalities and the presence of contrast enhancement.

RESULTS

All seven cases showed symmetric, confluent high signal intensity on T2-weighted images in the periventricular white matter and centrum semiovale. A posterior predominance of white matter abnormalities was noted in all cases. Although initially spared from demyelination in all cases, in one case, the subcortical U fibers were later involved in demyelination of follow-up MR studies. Other sites of involvement were the genu (n = 5) and splenium (n = 6) of the corpus callosum, the posterior limbs of the internal capsule (n = 5), the descending pyramidal tracts (n = 4), the claustrum (n = 4), and the cerebral white matter (n = 2); diffuse brain atrophy was seen in two cases. No enhancement of the lesion was seen on any of the five postcontrast examinations. A "tigroid" pattern, previously described in cases of Pelizaeus-Merzbacher disease, was noted in the centrum semiovale in six cases.

CONCLUSION

In late-infantile MLD, demyelination is more prominent in the occipital region. In addition to demyelination of the periventricular white matter, common manifestations include a "tigroid" pattern and involvement of the corpus callosum, the internal capsule, and the corticospinal tract.

Considerations for toxicology studies of respiratory drug products

The standard approaches for the preclinical development of chronically administered drugs also apply to most respiratory drugs. Modifications from the standard preclinical development plan, however, may be necessary if the drug is administered intranasally or by inhalation. Administration by these routes may result in airway toxicity and the intended patient population is often particularly susceptible. Current and former representatives of the Division of Pulmonary Drug Products (CDER, U.S. FDA) present this article to describe general principles of preclinical development for respiratory drug indications. The article addresses drugs intended for administration by the intranasal or inhalation routes. The article describes the types of studies recommended, considers the initial human dose, and discusses dose-escalation strategies in clinical trials. Other areas of special concern with intranasal or inhalation administration include immunotoxicity, reproductive toxicity, types of dosing apparatus, excipients and extractables, and formulation changes. The approaches described in this article are intended as general information and should be adapted to the scientific considerations and circumstances of a particular drug under development.

Epidural morphine plus ketamine for upper abdominal surgery: improved analgesia from preincisional versus postincisional administration

Increased postoperative pain may be caused by central nervous system plasticity, which may be related to actions of N-methyl-D-aspartic acid (NMDA) receptors on neurons in the dorsal horn of the spinal cord. Opioids act mainly on presynaptic receptors and reduce neurotransmitter release, while ketamine antagonizes NMDA receptors and prevents wind-up and long-term potentiation. Thus, we postulated that central nervous system sensitization would be prevented more effectively by the preoperative use of these two drugs simultaneously, and the effect of preemptive analgesia would be demonstrated. Ketamine, 60 mg, and morphine, 2 mg, were injected epidurally through an indwelling catheter that was inserted at the T7-8 interspace in 60 ASA physical status class 1-2 patients. The drugs were injected before induction of anesthesia (Group 1; n = 30) or immediately after removal of a surgical specimen (Group 2; n = 30). An additional 2 mg of morphine was injected when the patients complained of resting pain. The analgesic effect was assessed by the time from first analgesic injection to second dose and the number of patients who needed supplemental injections. Complications were also noted. The duration of analgesia was longer (P < 0.01) in Group 1 (31.1 +/- 16.0 h) than in Group 2 (21.1 +/- 12.0 h), and the proportion of patients who needed supplemental injections was decreased (P < 0.05) in Group 1 (56.7%) compared with Group 2 (90.0%). The incidence of adverse effects was not different between the two groups. In conclusion, preoperative administration of morphine and ketamine is more effective in reducing postoperative pain than it is when given during the operation.