Computational analysis of micron-particle deposition in a human triple bifurcation airway model

Steady laminar axisymmetric inhalation flow and wall deposition of micron-size particles in representative triple bifurcation airways have been simulated using a commercial finite-volume code with user-enhanced programs. Assuming spherical non-interacting particles (3 microm</=d(p)</=7 microm), various inlet Reynolds numbers (Re=500-2000) and Stokes numbers (St=0.02-0.23) were considered. The resulting particle deposition patterns were analyzed and then summarized in terms of deposition efficiencies, i.e. DE=DE(Re,St) Surprisingly high DE-values occur at relatively low Reynolds numbers (e.g., Re=500) in the third bifurcation. The quantitative results are of interest to researchers either conducting health risk assessment studies for inhaled particulate pollutants or analyzing drug aerosol inhalation and deposition at desired lung target sites.

Determination of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical preparation by capillary electrophoresis

A simple assay method of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical preparation was studied and validated by capillary electrophoresis (CE) using micellar electrokinetic chromatography (MEKC) techniques. Factors affecting the migration behavior and separation performances of the peptide; type of buffer, pH, buffer concentration, and concentration of sodium dodecyl sulfates (SDS) were investigated to optimize the analytical performance. CE was performed using running buffer, 50.0 mM borate (pH 8.5) containing 12.5 mM SDS at 20 kV of the applied voltage. Calibration curves for the rhEGF showed good linearity (r>0.999) over the wide dynamic range from 1.25 to 100 microg/ml. Sample analysis was performed by using standard addition method to eliminate the matrix effects of dosage vehicle. This method is assumed to be useful for quality control (QC) of various forms of pharmaceutical products of the peptide.

Gender differences in autonomic cardiovascular regulation: spectral, hormonal, and hemodynamic indexes

The autonomic nervous system drives variability in heart rate, vascular tone, cardiac ejection, and arterial pressure, but gender differences in autonomic regulation of the latter three parameters are not well documented. In addition to mean values, we used spectral analysis to calculate variability in arterial pressure, heart rate (R-R interval, RRI), stroke volume, and total peripheral resistance (TPR) and measured circulating levels of catecholamines and pancreatic polypeptide in two groups of 25 +/- 1.2-yr-old, healthy men and healthy follicular-phase women (40 total subjects, 10 men and 10 women per group). Group 1 subjects were studied supine, before and after beta- and muscarinic autonomic blockades, administered singly and together on separate days of study. Group 2 subjects were studied supine and drug free with the additional measurement of skin perfusion. In the unblocked state, we found that circulating levels of epinephrine and total spectral power of stroke volume, TPR, and skin perfusion ranged from two to six times greater in men than in women. The difference (men > women) in spectral power of TPR was maintained after beta- and muscarinic blockades, suggesting that the greater oscillations of vascular resistance in men may be alpha-adrenergically mediated. Men exhibited muscarinic buffering of mean TPR whereas women exhibited beta-adrenergic buffering of mean TPR as well as TPR and heart rate oscillations. Women had a greater distribution of RRI power in the breathing frequency range and a less negative slope of ln RRI power vs. ln frequency, both indicators that parasympathetic stimuli were the dominant influence on women's heart rate variability. The results of our study suggest a predominance of sympathetic vascular regulation in men compared with a dominant parasympathetic influence on heart rate regulation in women.

Induced thermolysis of tert-butyl phenylperacetates by thiophenol: simultaneous occurrence of homolysis and single electron transfer

Thermolysis of tert-butyl phenylperacetates in the presence of thiophenol takes place via dual mechanism. The two-bond homolysis indicates rho(+)(4)= -1.16, testifying to polar transition states. The single electron transfer yields a radical anion intermediate which undergoes fragmentation with rho(ET) = 1.01.

Epinephrine, vasodilation and hemoconcentration in syncopal, healthy men and women

Healthy young people may become syncopal during standing, head up tilt (HUT) or lower body negative pressure (LBNP). To evaluate why this happens we measured hormonal indices of autonomic activity along with arterial pressure (AP), heart rate (HR), stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR) and measures of plasma volume. Three groups of normal volunteers (n = 56) were studied supine, before and during increasing levels of orthostatic stress: slow onset, low level, lower body negative pressure (LBNP) (Group 1), 70 degrees head up tilt (HUT) (Group 2) or rapid onset, high level, LBNP (Group 3). In all groups, syncopal subjects demonstrated a decline in TPR that paralleled the decline in AP over the last 40 s of orthostatic stress. Ten to twenty seconds after the decline in TPR. HR also started to decline but SV increased, resulting in a net increase of CO during the same period. Plasma volume (PV, calculated from change in hematocrit) declined in both syncopal and nonsyncopal subjects to a level commensurate with the stress, i.e. Group 3 > Group 2 > Group 1. The rate of decline of PV, calculated from the change in PV divided by the time of stress, was greater (p < 0.01) in syncopal than in nonsyncopal subjects. When changes in vasoactive hormones were normalized by time of stress, increases in norepinephrine (p < 0.012, Groups 2 and 3) and epinephrine (p < 0.025, Group 2) were greater and increases in plasma renin activity were smaller (p < 0.05, Group 2) in syncopal than in nonsyncopal subjects. We conclude that the presyncopal decline in blood pressure in otherwise healthy young people resulted from declining peripheral resistance associated with plateauing norepinephrine and plasma renin activity, rising epinephrine and rising blood viscosity. The increased hemoconcentration probably reflects increased rate of venous pooling rather than rate of plasma filtration and, together with cardiovascular effects of imbalances in norepinephrine, epinephrine and plasma renin activity may provide afferent information leading to syncope.

Suppressive effects of genistein dosage and resistance exercise on bone loss in ovariectomized rats

This study was designed to determine whether combined treatments with genistein dosage and moderate resistance exercise would exhibit synergistically preventive effects on bone loss following the onset of menopause. Forty-one 12 wk-old female SD rats were assigned to five groups: 1) Sham operated (Sham); 2) ovariectomized (OVX-Cont); 3) OVX received genistein (OVX-GEN); 4) OVX exercised (OVX-EXE); and 5) OVX treated with both genistein and exercise (OVX-GEN-EXE). All rats were fed a low Ca (0.1%) diet ad libitum. Daily genistein dosage was 12 mg/kg body weight. Exercising rats took 40 sets of 1-min run interspersed with 1-min rest with a 100 g weight on the back on an uphill treadmill at 20 m/min. The experimental duration consisted of the adaptation and treatment periods of 4 weeks each. Uterine weight in OVX-Cont, OVX-GEN, OVX-EXE and OVX-GEN-EXE decreased to about 15% of that in Sham (p < 0.001). The femoral BMD (mg/cm2; mean +/- SE), assessed by DEXA (Lunar), of OVX-Cont was significantly lowered to 206 +/- 5 by -9%, as compared to 226 +/- 2 of Sham (p < 0.001). The BMD of OVX-GEN, OVX-EXE and OVX-GEN-EXE were 217 +/- 2, 217 +/- 2 and 222 +/- 2, respectively, and genistein dosage and resistance exercise equally increased the BMD of OVX rats by 5% (p < 0.01). Combined treatment of genistein and exercise more successfully recovered their decreased BMD by 8% (p < 0.001). BMD of the fourth lumbar vertebrae in OVX-Cont was declined to 191 +/- 7 by -15%, as compared to 225 +/- 4 in Sham (p < 0.001). OVX-EXE and OVX-GEN-EXE gained the BMD by 6% to 205 +/- 4 and 203 +/- 3, respectively, as compared to that of OVX-Cont (p < 0.01). These results suggest the possibility that the combined treatment of genistein dosage and resistance exercise have more beneficial effects by acting rather independently than their separate trials on the prevention of ovx-induced bone loss in femurs.

Depletion of praziquantel in plasma and muscle tissue of cultured rockfish Sebastes schlegeli after oral and bath treatment

Depletion of praziquantel in plasma and muscle tissue after oral and bath treatments was studied in cultured rockfish Sebastes schlegeli. In the oral treatment, a single dose of 400 mg praziquantel kg(-1) body weight was administered by intubation of the stomach. A bath treatment at 100 ppm of praziquantel for 4 min was also carried out. Plasma and muscle tissue samples were collected at 3, 6, 12, 24, 48, 72, 96, 120, 144 and 168 h post-treatment, and analyzed for praziquantel by reversed-phase HPLC using diazepam as the internal standard. Following oral treatment, praziquantel was detected in plasma and muscle tissue until 96 h after treatment. In plasma the praziquantel concentration was highest at the 9 h sampling time and declined sharply at the 48 h sampling point. The concentrations of praziquantel in the muscle tissue were lower than those in the plasma, and the highest value was found at the 9 h sampling time. Following bath treatment, praziquantel was found in plasma and muscle tissue until 72 and 24 h after treatment, respectively. In plasma the praziquantel concentration was highest at the 12 h sampling time and declined sharply thereafter. The concentrations of praziquantel in the muscle tissue were significantly lower than those in the plasma, and the concentrations declined consistently with time.

Effect of acute anemia on the healing of intestinal anastomoses in the rabbit

BACKGROUND

Considering the potential deleterious effects of transfusion, the effect of severe, acute anemia on small intestine (SI) and large intestine (LI) anastomoses was evaluated.

METHODS

Thirty-six rabbits underwent segmental resection of the midileum and distal colon. Half underwent preanastomotic removal of 30% of their blood volume with crystalloid resuscitation. At 1 or 2 weeks, the anastomotic bursting pressure (ABP) and histologic grade of white blood cell influx, blood vessel ingrowth, fibroblast proliferation, and collagen deposition were assessed.

RESULTS

SI ABP was decreased in anemic rabbits at 2 weeks (190 +/- 6 mm Hg vs. 257 +/- 17 mm Hg). LI ABP was decreased at 1 week in anemic rabbits. In the test rabbits, histologic parameters were altered in both the SI and LI with decreased white blood cell infiltration, attenuated blood vessel ingrowth, and decreased collagen content at both 1 and 2 weeks. Decreased SI fibroblast proliferation was present at 1 week.

CONCLUSION

Acute anemia in the rabbit undergoing intestinal resection decreases the SI ABP at 2 weeks and alters histologic parameters of wound healing in both the SI and LI.

Determination of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical formulation by high performance liquid chromatography with electrochemical detection

A novel HPLC method with electrochemical detection has been developed for the determination of recombinant human epidermal growth factor (rhEGF) in pharmaceutical products. rhEGF was separated from other components in formulation on a reversed-phase C18 column with 24% acetonitrile in 0.1 M phosphate buffer (pH 4.75). The optimum electrochemical oxidation of EGF was obtained at 0.85 V vs. Ag/AgCl in a glassy carbon working electrode due to electroactive tyrosine, tryptophan, methionine, and arginine residues. The quantitation range was from 1.0 to 200 ng of rhEGF with the linear correlation coefficient greater than 0.999. The method was successfully applied for the quantitation of rhEGF in a pharmaceutical preparation.

Fluoroscopic-guided covered metallic stent placement for gastric outlet obstruction and post-operative gastroenterostomy anastomotic stricture

AIM

To evaluate the feasibility and safety of fluoroscopic-guided covered metallic stent placements in providing palliative care for patients with inoperable malignant gastric outlet obstruction.

MATERIALS AND METHODS

Under fluoroscopic guidance, placement of self-expandable, covered stents was attempted in 20 patients with inoperable or recurrent gastric cancer (age range 36-79 years). All patients had inoperable gastric outlet obstruction, 13 with native anatomy and seven with post-operative anatomy (gastrointestinal anastomotic sites). All patients had intolerance to oral alimentation and/or vomiting after ingestion. Success was defined both technically and clinically.

RESULTS

The placement of the stent was technically successful in 18 patients and failed in two patients (technical success: 90%). The cause of the technical failures was an inability to negotiate the guide wire through the obstruction sites in spite of the use of both fluoroscopic and endoscopic guidance. After stent placement, 15 patients were able to ingest at least liquids and had a markedly decreased incidence of vomiting (clinical success: 75%). During the mean follow-up of 6 weeks, there have been no stent reocclusion and no life-threatening complications except migration of two stents in one patient.

CONCLUSION

Fluoroscopically guided covered metallic stent placement appears to be valuable for the palliative treatment of malignant obstruction of gastric outlet and post-operative gastrointestinal anastomoses.

Rate of visual field loss and long-term visual outcome in primary open-angle glaucoma

PURPOSE

To evaluate long-term visual field outcome in primary open-angle glaucoma.

METHODS

In this retrospective cohort study, 40 eyes of 40 patients with primary open-angle glaucoma with elevated intraocular pressure and a minimum of 8-year longitudinal series of visual fields were plotted with Goldmann perimeter. Eyes with any other ocular disease except cataract were excluded. Manual grid templates were used to quantify the visual fields. Linear regression was performed to estimate the rate of visual field decline. Pertinent clinical factors were evaluated for statistical association with the rate of decline. Long-term clinical outcome including visual acuity, rate of legal blindness, and rate of medical and surgical interventions was also measured.

RESULTS

In the 40 eyes studied, with a mean follow-up of 14 years, the visual field score decreased at the rate of -1.5% per year. Overall, 68% showed significant decrease, and the rate of decrease among these eyes was -2.1% per year. Five eyes became legally blind from glaucoma; the cumulative rate of blindness from glaucoma was 19% at 22 years. Higher intraocular pressure and greater number of antiglaucoma medications on initial presentation were associated with faster and slower deterioration of visual field (compared with the average), respectively.

CONCLUSIONS

With standard glaucoma therapy, the rate of visual field loss in primary open-angle glaucoma is slow. Lower intraocular pressure and more antiglaucoma medications are associated with slower visual field decline. Legal blindness from glaucoma is 19% over a follow-up of 22 years.

Phase II trial of epirubicin, cisplatin, oral uracil and tegafur, and leucovorin in patients with advanced gastric carcinoma

BACKGROUND

The results of chemotherapy for patients with gastric carcinoma generally have been modest, although regimens developed more recently have produced higher response rates. One such regimen is epirubicin, cisplatin, and protracted infusion of 5-fluorouracil (ECF). The advantage of a long-term oral administration of uracil and tegafur (UFT) is that this treatment may be used to mimic the protracted infusion of 5-fluorouracil (5-FU). In addition, UFT treatment combined with leucovorin had a favorable activity and tolerable toxicity in patients with advanced gastric carcinoma. Instead of the inconvenience of an infusion pump and intravenous catheter for the protracted infusion of 5-FU, the authors administered UFT plus leucovorin in an ECF regimen for the treatment of patients with advanced gastric carcinoma.

METHODS

Fifty-two patients with advanced gastric carcinoma received epirubicin, cisplatin, and oral UFT plus leucovorin. Epirubicin 50 mg/m(2) and cisplatin 60 mg/m(2) were administered on Day 1 by intravenous injection. Tegafur and uracil 360 mg/m(2)/day orally was administered in conjunction with leucovorin administered at a fixed dose of 45 mg/day orally in divided daily doses for 21 days followed by a 7-day rest period. These courses were repeated every 4 weeks. The median age of the patients was 59 years with a median World Health Organization performance status of 1. Patients received a median of five courses of treatment (range, 1-10).

RESULTS

Among the 47 patients evaluated, three patients achieved complete response, and 24 patients had partial responses, for an overall response rate of 57.5% (95% confidence interval, 71.5-43.3%). Stable disease was reported in 11 patients (23.4%), and another 9 patients (19.1%) showed disease progression. The median duration of survival was 15 months (range, 2-33+). The main toxicity was nausea/vomiting and neutropenia. Significant toxicity (modified National Cancer Institute common toxicity Grade 3 or 4) included neutropenia in 22 patients (42%), nausea in 14(27%), vomiting in 9 (18%), oral mucositis in 3 (6%), and diarrhea in 3 (6%) patients.

CONCLUSIONS

The authors conclude that epirubicin, cisplatin, and oral UFT plus leucovorin, a convenient regimen, has a significant activity and tolerable toxicities in patients with gastric carcinoma.

Antifeedants against Acusta despesta from the Japanese cedar, Cryptomeria japonica II

Cryptomeria japonica against Acusta despesta. This hexane soluble-fraction was used to isolate and identify two sesquiterpenols, (-)-cubebol and (+)-2,7(14),10-bisabolatrien-1-ol-4-one, as the active compounds. Both compounds strongly inhibited the feeding behavior of A. despesta at 120 microg/cm2 and 80 microg/cm2 concentrations, respectively.

Effects of curved inlet tubes on air flow and particle deposition in bifurcating lung models

In vivo bifurcating airways are complex and the airway segments leading to the bifurcations are not always straight, but curved to various degrees. How do such curved inlet tubes influence the motion as well as local deposition and hence the biological responses of inhaled particulate matter in lung airways? In this paper steady laminar dilute suspension flows of micron-particles are simulated in realistic double bifurcations with curved inlet tubes, i.e., 0 degrees < or =theta< or =90 degrees, using a commercial finite-volume code with user-enhanced programs. The resulting air-flow patterns as well as particle transport and wall depositions were analyzed for different flow inlet conditions, i.e., uniform and parabolic velocity profiles, and geometric configurations. The curved inlet segments have quite pronounced effects on air-flow, particle motion and wall deposition in the downstream bifurcating airways. In contrast to straight double bifurcations, those with bent parent tubes also exhibit irregular variations in particle deposition efficiencies as a function of Stokes number and Reynolds number. There are fewer particles deposited at mildly curved inlet segments, but the particle deposition efficiencies at the downstream sequential bifurcations vary much when compared to those with straight inlets. Under certain flow conditions in sharply curved lung airways, relatively high, localized particle depositions may take place. The findings provide necessary information for toxicologic or therapeutic impact assessments and for global lung dosimetry models of inhaled particulate matter.

Quantitative trait locus mapping of loci influencing elongation factor 1alpha content in maize endosperm

The nutritional value of maize (Zea mays) seed is most limited by its protein quality because its storage proteins are devoid of the essential amino acid lysine (Lys). The Lys content of the kernel can be significantly increased by the opaque-2 mutation, which reduces zein synthesis and increases accumulation of proteins that contain Lys. Elongation factor 1alpha (eEF1A) is one of these proteins, and its concentration is highly correlated with the Lys content of the endosperm. We investigated the genetic regulation of eEF1A and the basis for its relationship with other Lys-containing proteins by analyzing the progeny of a cross between a high (Oh51Ao2) and a low (Oh545o2) eEF1A maize inbred. We identified 83 simple sequence repeat loci that are polymorphic between these inbreds; the markers are broadly distributed over the genome (1,402 cM) with an average interval of 17 cM. Genotypic analysis of the F(2) progeny revealed two significant quantitative trait loci that account for 25% of the variance for eEF1A content. One of these is on the short arm of chromosome 4 and is linked with a cluster of 22-kD alpha-zein coding sequences; the other quantitative trait locus is on the long arm of chromosome 7. The content of alpha-zein and gamma-zein was measured in pools of high- and low-eEF1A individuals obtained from this cross, and a higher level of alpha-zein was found to cosegregate with high eEF1A content. Allelic variation at the 22-kD alpha-zein locus may contribute to the difference of eEF1A content between Oh51Ao2 and Oh545o2 by increasing the surface area of protein bodies in the endosperm and creating a more extensive network of cytoskeletal proteins.

Enhanced gene expression of renin-angiotensin system, TGF-beta1, endothelin-1 and nitric oxide synthase in right-ventricular hypertrophy

It has been suggested that various vasoactive substances and growth factors are involved in left-ventricular myocardial hypertrophy and failure. However, limited data are available on the role of humoral factors involved in right-ventricular (RV) hypertrophy. To examine implications of humoral factors involved in the development of RV hypertrophy, altered mRNA expressions of the renin-angiotensin system (RAS), transforming growth factor (TGF)- beta1, endothelin-1 and nitric oxide synthase (NOS) were investigated in monocrotaline (MCT)-induced pulmonary hypertensive rats. Male Sprague-Dawley rats were treated with MCT (60 mg x kg(-1), s.c.) to induce a selective RV hypertrophy. Three or 6 weeks later, the heart was removed to determine the tissue gene expressions in the right and left ventricles (LV) by reverse transcription-polymerase chain reaction due to the relatively low mRNA expression levels of the RAS components in the ventricle (n= 6 in each group). MCT-treated rats showed a selective RV hypertrophy at weeks 3 and 6 of MCT treatment (the ratios of RV/body weight were 1.5- and 2.2-fold higher than the controls, respectively). Levels of renin and angiotensinogen mRNAs in the hypertrophied RV were significantly increased at both weeks 3 and 6 of MCT treatment. The angiotensin-converting enzyme mRNA level also increased approximately 2-fold at week 3. In contrast, RAS component mRNAs in the LV were not significantly altered by MCT treatment, except for a 1.8-fold increase of angiotensinogen mRNA at week 3. The expression of Ang II receptors, either AT1A or AT1B, was not significantly altered by MCT treatment. Furthermore, MCT treatment significantly increased TGF- beta1 mRNA levels in the RV at weeks 3 and 6, while it did not significantly affect them in the LV. Endothelin-1 mRNA expression was significantly higher in the RV at week 3, but was normalized at week 6 of MCT treatment. The gene expression of the endothelial constitutive isoform of NOS was increased in the RV at weeks 3 and 6, but not in the LV. Elevated gene expression of local RAS, along with TGF- beta1 and endothelin-1 in the present study may contribute to the development of RV hypertrophy. On the contrary, an enhanced ecNOS expression may be a mechanism counteracting the hypertrophy.

Postoperative pain management using intravenous patient-controlled analgesia for pediatric patients

Pain control is an important consideration after any surgical procedures. Especially in children, more attention and care are needed during the period of postoperative pain control, which must be both sufficiently safe and effective. In this respect, intravenous patient-controlled analgesia provides improved titration of analgesic drugs, thereby maintaining optimal analgesic status with few side effects. Thirty pediatric patients were randomly divided into two groups: the intravenous patient-controlled analgesia group (with nalbuphine HCl and ketorolac tromethamine) and the conventional pethidine HCl intramuscular group. The degree of analgesia was assessed every 4 hours until the second postoperative day. The intravenous patient-controlled analgesia group had significantly lower pain scores and took less time until they were able to walk to the bathroom, but as many side effects as the control group. We concluded that intravenous patient-controlled analgesia is safe and effective for pediatric patients who have moderate to severe pain after operations such as rib cartilage graft, iliac bone graft, and large flap surgeries.

Scalp aplasia cutis congenita presenting with sagittal sinus hemorrhage

We describe an infant with aplasia cutis congenita of the scalp complicated by sagittal sinus hemorrhage. The defect was successfully managed by primary closure with scalp flaps. The literature on aplasia cutis congenita is reviewed, including etiology, genetic transmission, associated anomalies, and options for management. The potentially fatal outcome highlights the importance of early surgical coverage of the exposed superior sagittal sinus to avoid life-threatening hemorrhage and other complications.

MR imaging-histopathologic correlation of radiofrequency thermal ablation lesion in a rabbit liver model: observation during acute and chronic stages

OBJECTIVE

To determine the ability of MR imaging to detect the pathological changes occurring in radiofrequency (RF) thermal lesions and to assess its accuracy in revealing the extent of tissue necrosis.

MATERIALS AND METHODS

Using an RF electrode, thermal lesions were created in the livers of 18 rabbits. The procedure involved three phases. In the acute phase, six animals were killed the day after performing thermal ablation with RF energy, and two on day 3. In the subacute and chronic phases, eight rabbits underwent percutaneous hepatic RF ablation. After performing MR imaging, two animals were sacrificed at 1, 2, 4, and 7 weeks after the procedure, and MR-pathologic correlation was performed.

RESULTS

In the acute phase, the thermal ablation lesions appeared at gross examination as well-circumscribed, necrotic areas, representing early change in the coagulative necrosis seen at microscopic examination. They were hypointense on T2-weighted images, and hyperintense on T1-weighted images. Gadolinium-enhanced MR imaging showed that a thin hyperemic rim surrounded the central coagulative necrosis. In the subacute phase, ablated lesions also showed extensive coagulative necrosis and marked inflammation at microscopic examination. Beyond two weeks, the lesions showed gradual resorption of the necrotic area, with a peripheral fibrovascular rim. The size of lesions measured by MR imaging correlated well with the findings at gross pathologic examination.

CONCLUSION

MR imaging effectively demonstrates the histopathological tissue change occurring after thermal ablation, and accurately determines the extent of the target area.

Palliation of postoperative gastrointestinal anastomotic malignant strictures with flexible covered metallic stents: preliminary results

PURPOSE

To evaluate the efficacy of the placement of covered metallic stents for palliation of gastrointestinal anastomotic strictures secondary to recurrent gastric cancer.

METHODS

Under fluoroscopic guidance, placement of one or two self-expandable covered metallic stents was attempted perorally in 11 patents (aged 48-76 years) with anastomotic stenoses due to recurrent gastric malignancies. The strictures involved both the afferent and efferent loops in three patients. All patients had poor peroral food intake with severe nausea and vomiting after ingestion. The technical and clinical success was evaluated.

RESULTS

Placement of the covered stent was technically successful in 13 of 15 (87%) attempts in ten patients. After the procedure, 9 of 11 (82%) patients overall were able to ingest at least a liquid diet and had markedly decreased incidence of vomiting. During the follow-up of 2-31 weeks (mean 8.5 weeks) there were no major complications.

CONCLUSION

These preliminary results suggest that flexible, covered stents may provide effective palliation of malignant anastomotic stricture secondary to recurrent gastric cancer.

Effects of beta-toxin of Staphylococcus aureus on ciliary activity of nasal epithelial cells

OBJECTIVES

To investigate the in vitro effects of staphylococcal beta-toxin on ciliary activity and the in vivo effects on sinusitis induction.

STUDY DESIGN

The in vitro effects of staphylococcal beta-toxin on ciliary activity were investigated at different concentrations and exposure times. Experimental sinusitis was induced in rabbits with application of beta-toxin and confirmed 7 days later.

METHODS

Ciliated epithelial cells were taken from the maxillary sinus mucosa of 10 rabbits. Five culture dishes from each rabbit were used for the experimental group, and one culture dish from each rabbit was used for the control group. In the experimental group, ciliary beat frequency (CBF) was measured at concentrations of 0.1, 1, 2, 5 and 10 U/mL of beta-toxin using a video-computerized analysis technique, while in the control group, culture medium containing no toxin was used. CBF was measured 1, 2, 4, 6, 8, 12, 24, and 48 hours after administration of beta-toxin. To induce experimental sinusitis, 2 U/mL of beta-toxin was percutaneously applied to the maxillary sinus of 10 rabbits without occlusion of the natural ostium, while normal saline was percutaneously applied to the right-side maxillary sinus of 4 rabbits in the control group. At 7 days, mucosal membranes were taken from the inferomedial wall of the maxillary sinus for light microscopic study.

RESULTS

CBF dropped significantly after an 8-hour incubation at 2, 5, and 10 U/mL of beta-toxin. No ciliary activity was observed after a 24-hour incubation at 2 and 5 U/mL and a 12-hour incubation at 10 U/mL of beta-toxin. Mucoid, purulent discharge was observed in the maxillary sinuses of the beta-toxin-applied group. Prominent epithelial disruption and infiltration of inflammatory cells into the epithelium and lamina propria were observed in the beta-toxin-applied group.

CONCLUSIONS

Staphylococcal beta-toxin may reduce ciliary activity and induce sinusitis without occlusion of the natural ostium of the maxillary sinus in rabbits This study provides another animal model of sinusitis for understanding the pathogenesis of sinusitis induced by bacterial exotoxins.

Effect of Korean red ginseng on blood pressure and nitric oxide production

AIM

To investigate the effect of crude saponin and nonsaponin fraction of Korean red ginseng (KRG) on the blood pressure and nitric oxide (NO) production in the conscious rats and cultured endothelial cell line, ECV 304 cells.

METHODS

Systolic blood pressure and heart rate were monitored in the conscious rats. Nitric oxide levels and the expression of nitric oxide synthase were measured by a spectrophotometric assay using Griess reagents and Western blotting, respectively. Nitric-oxide synthase activity was measured based on the conversion rate of [3H]arginine to [3H]citrulline.

RESULTS

Systolic blood pressure was decreased by crude saponin (100 mg/kg, i.v.) of KRG in the conscious control and one-kidney, one-clip Goldblatt hypertensive (1K, 1C-GBH) rats. The hypotensive effect induced by crude saponin of KRG reached maximum at 2-4 min and slowly recovered after 20 min to the initial level in both groups. Crude saponin of KRG induced tachycardia in the conscious rats but induced bradycardia in the anesthetized rats. In contrast to crude saponin of KRG, hypotensive effect induced by saponin-free fraction was minimal. Nitric oxide concentrations were increased by the treatment of crude saponin in conscious rats as well as in the cultured ECV 304 cells. The protein expression level of endothelial constitutive nitric-oxide synthase (eNOS) in the aorta of rats was not increased by crude saponin (100 mg/kg, i.p. for 3 d). However, nitric-oxide synthase activity was increased by crude saponin of KRG in the aortic homogenate of rats.

CONCLUSION

The hypotensive effect of red ginseng is mainly due to saponin fraction of KRG in the conscious rats, and this effect may be due to an increase in the nitric-oxide production by KRG.

Biochemical responses of fish exposed to a harmful dinoflagellate Cochlodinium polykrikoides

To elucidate the ichthyotoxic mechanisms of a harmful dinoflagellate Cochlodinium polykrikoides, biochemical responses of fish exposed to blooms were investigated. Particularly, based on our finding that oxidative damages of gill were associated with fish mortality (J. Plankton Res. 21 (1999) 2105-2115), dysfunction of ion-transporting enzymes and secretion of gill mucus of fish exposed to this bloom species were examined. The susceptibilities of several fishes to C. polykrikoides were different; the active pelagic fishes such as black scraper Thamnaconus septentrionalis, red sea bream Pagrus major, beakperch Oplegnathus fasciatus and seaperch Malakichthys wakiyae, were more vulnerable than the benthic fishes, flounder Paralichthys olivaceus and rockfish Sebastes inermis. In addition, the higher the algal cell density, the higher the fish mortality. When the test fishes were exposed to C. polykrikoides of 5000 cells ml(-1), the transport-related enzymes, carbonic anhydrase and Na(+)/K(+)-ATPase activities were significantly decreased. The activity of carbonic anhydrase was decreased with increasing algal cell density and exposure time. The quantity of total polysaccharide in gill mucus is higher in the fish exposed to C. polykrikoides than in the control fish; the magnitudes were higher in the pelagic fishes than that of benthic fishes. Moreover, a drop of blood pH and oxygen partial pressure (pO(2)) was also observed in red sea bream and flounder subjected to C. polykrikoides. These results suggest that the inactivation of gill transport-related enzymes activities, the fall in blood pO(2) and abnormal secretion of gill mucus by the C. polykrikoides may be one of the principal causes of fish kill.

Positioning of a double-lumen endobronchial tube without the aid of any instruments: an implication for emergency management

BACKGROUND

Lung isolation and preservation of normal lung are the first lines of therapy in life-threatening massive hemoptysis. If bleeding continues but the side of origin is uncertain, use of a double-lumen tube (DLT) is reasonable. Utilizing a blind method to locate the bronchial cuff of a left-sided DLT without using any instrument, a DLT (Broncho-Cath, Mallinckrodt Medical Ltd., Athlone, Ireland) was successfully positioned without delay in a patient with massive hemoptysis, where auscultation could be misleading or useless and fiberoptic bronchoscope (FOB) was inapplicable. This study was performed to discern whether this blind method could substitute for FOB verification or auscultation in most circumstances where these two methods are unavailable or inapplicable.

METHODS

After receiving informed consent and hospital ethics board approval, 58 elective thoracic surgical patients, aged 17 to 67 years, were enrolled in the study and divided into two groups. A conventional method using an FOB was used to locate the left-sided DLT in 29 patients (group 1). In the other 29 patients (group 2), the blind manual method was used. The left-sided DLT was inserted until some resistance was felt, at which time the bronchial cuff was inflated with approximately 2.0 mL of air. While gently holding the pilot with thumb and index finger of the nondominant hand, the DLT was slowly withdrawn until an abrupt decrease of pilot pressure was sensed. At that moment, the bronchial cuff was deflated, and the DLT was advanced approximately 1.5 cm; using an FOB, its position was checked by an independent observer not involved in positioning the DLT. Success was defined as the point when the proximal margin of the carina was within the margin of safety for the DLT, which is defined as the difference between the length of the left main bronchus and the length of the tube between the proximal margin of the left bronchial cuff and the left lumen tip. Postoperative FOB was performed to evaluate bronchial injury.

RESULTS

In 26 of 29 patients (group 2), the position of the DLT was bronchoscopically confirmed to be a success. The other three cases were deemed to be too shallow; specifically, the bronchial cuffs were slightly herniated onto the carina (acceptable position). This method was more traumatic than FOB-guided DLT intubation (conventional method) (p = 0.001); however, the most severe damage was erosion.

CONCLUSION

This method, which requires no specific instrument and no time-consuming technique, can be taught easily and may be used in a situation where the rapidity of lung isolation or collapse is the key to saving life. We conclude that this blind method can be an alternative to the FOB and/or auscultation for the positioning of DLT in an emergency situation.