Correlation of rectum-associated lymph nodules with the development of experimentally induced acute colonic inflammation in rats

BACKGROUND AND AIMS

The mechanisms of inflammation in ulcerative colitis occurring initially in the rectum and then extending throughout the colon are still unknown. The aim of this study is to investigate the correlation of rectum-associated lymph nodules (RALN) and the development of a dextran sulfate sodium-induced experimentally acute colonic inflammation in rats.

METHODS

We immunohistochemically analyzed the lymph nodules in the rectal region of rats using monoclonal antibodies to specific markers.

RESULTS

Rectum-associated lymph nodules resembled the Peyer's patches, where CD4+, CD8+ lymphocytes and Mar 1+ macrophages were observed. After the administration of dextran-sulfate sodium (DSS), RALN showed hypertrophy with an increase in the number of CD4+, CD8+, and interleukin (IL)-2R+ lymphocytes in the periphery, as well as Mar 1+ macrophages in the entire region. Concurrently, platelet/endothelin cell adhesion molecule-1 (PECAM-1+) blood vessels, including high-endothelial venules (HEV), were increased in number in the interfollicular areas. Furthermore, a number of small lymph nodules varying in size were observed in the upper region of the rectum. Some of them were initially confined to the lamina propria mucosae, and became large enough to extend deeper into the tela submucosa. These DSS-induced lymph nodules contained large numbers of CD4+ lymphocytes, IL-2R+ lymphocytes, and Mar 1+ macrophages.

CONCLUSIONS

The pathological changes of ulcerative colitis were well correlated with the development of both RALN and DSS-induced lymph nodules. The immunological reaction that occurred in DSS-induced lymph nodules is significantly associated with the expansion of colitis from the lower region of rectum to the upper region of rectum and colon.

Hemodynamic exercise response in calves with an implantable biventricular centrifugal blood pump

An implantable biventricular assist device (BVAD) has been developed at Baylor College of Medicine using 2 centrifugal blood pumps. The aim of this study was to investigate the exercise-reflex response during nonpulsatile biventricular assistance and to evaluate to which degree the autoregulation of the system would accommodate the changed hemodynamic situation during physical exercise. The Baylor Gyro PI 710 BVAD has been implanted into 2 calves (strain half-Dexter) in a biventricular bypass fashion with native heart remaining. Allowing a 10 day convalescence, 2 animals were subjected to incremental exercise tests. The speed of the treadmill was increased at zero slope from 0.7 mph to 1.5 mph with increments of 0.2 mph every 3 min. During the exercise the pump flows were maintained at a fixed rate (6.93 +/- 0.01 L/min for the left ventricular assist device and 5.36 +/- 1.44 L/min for the right ventricular assist device). Hemodynamic parameters and pump performance were recorded continuously. The cardiac output (CO) and heart rate (HR) increased significantly during the exercise. CO increased from 11.1 +/- 0.3 to 13.1 +/- 0.4 L/min, and HR increased from 99 +/- 7.1 to 114 +/- 2.8 bpm, respectively. Mean aortic pressure, central venous pressure, and left arterial pressure did not change significantly. Also, no change was observed for the left and right pump flows. This totally implantable BVAD showed excellent long-term performance without any mechanical problems. It is feasible to operate without impairment under physical activity. However, the natural heart dominated the hemodynamic response during exercise under BVAD support. The left and the right pump flows did not increase spontaneously with exercise. We therefore conclude that a servo CO control system is necessary to regulate pump flows even during moderate exercise.

Long-term effects of olmesartan, an Ang II receptor antagonist, on blood pressure and the renin-angiotensin-aldosterone system in hypertensive patients

The object of this study is to evaluate the long-term effects of olmesartan on hypertension and the renin-angiotensin-aldosterone system in hypertensive patients. This study evaluated 26 hypertensive male and female outpatients, 38-69 years of age, with a systolic blood pressure > or = 160 mmHg and/or a diastolic blood pressure > or = 95 mmHg. Oral doses of 5 to 40 mg olmesartan were administered once daily. Blood pressure and renin-angiotensin-aldosterone parameters (plasma renin activity and plasma angiotensin I, II, and aldosterone concentrations) were evaluated at 12-16 weeks, 6 months, and 1 year after the start of olmesartan administration. Systolic and diastolic blood pressures were significantly decreased following the administration of olmesartan. The observed decreases in systolic and diastolic blood pressures after 1 year of treatment were 28.8+/-2.1 mmHg and 15.8+/-1.3 mmHg, respectively. No change was observed in the pulse rate. The plasma renin activity increased significantly from a baseline premedication mean of 1.26+/-0.31 ng/ml/h to a mean of 2.58+/-0.74 ng/ml/h and 2.87+/-0.72 ng/ml/h after 6 months and 1 year of treatment, respectively. Angiotensin II levels decreased significantly from a baseline of 20.4+/-3.2 pg/ml to a mean of 8.6+/-2.1 pg/ml and 6.8+/-1.8 pg/ml after 6 months and 1 year of treatment, respectively. The plasma aldosterone level also decreased significantly after 6 months of treatment. In hypertensive patients, the long-term administration of olmesartan, a novel AT1 receptor antagonist, decreased both blood pressure and plasma angiotensin II levels.

[Coronary artery bypass-grafting using interrupted anastomosis with the U-clip]

For coronary artery anastomosis, the continuous suture technique is generally used because it is easy to perform, there is less anastomotic leakage, and a shorter anastomotic time compared with the interrupted suture technique. However, with this technique there is a potential risk of anastomotic stenosis caused by the purse-string effect, which does not occur with the interrupted suture technique. The U-Clip device was designed to facilitate the interrupted suture technique in coronary anastomosis by eliminating the need for suture management, knot tying, and surgical assistance. The device employs the superelastic properties of nitinol and two components: 1. a needle/suture delivery system, and 2. a detachable nitinol self-closing wire. We used this device successfully for LITA-LAD anastomosis in MIDCAB. When this device is applied to small caliber conduits, such as the internal thoracic arteries and the gastroepiploic artery, the side-to-side anastomosis can reduce the anastomotic leakage more efficiently, since the coronary incision and graft incision can be perfectly matched. The U-Clip facilitates coronary anastomosis by simplifying and decreasing the amount of manipulation and complexity required in minimally invasive CABG procedures. Nitinol technology also has potential in robotic and endoscopic surgical applications.

Enzymes inside lipid vesicles: preparation, reactivity and applications

There are a number of methods that can be used for the preparation of enzyme-containing lipid vesicles (liposomes) which are lipid dispersions that contain water-soluble enzymes in the trapped aqueous space. This has been shown by many investigations carried out with a variety of enzymes. A review of these studies is given and some of the main results are summarized. With respect to the vesicle-forming amphiphiles used, most preparations are based on phosphatidylcholine, either the natural mixtures obtained from soybean or egg yolk, or chemically defined compounds, such as DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) or POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine). Charged enzyme-containing lipid vesicles are often prepared by adding a certain amount of a negatively charged amphiphile (typically dicetylphosphate) or a positively charged lipid (usually stearylamine). The presence of charges in the vesicle membrane may lead to an adsorption of the enzyme onto the interior or exterior site of the vesicle bilayers. If (i) the high enzyme encapsulation efficiencies; (ii) avoidance of the use of organic solvents during the entrapment procedure; (iii) relatively monodisperse spherical vesicles of about 100 nm diameter; and (iv) a high degree of unilamellarity are required, then the use of the so-called 'dehydration-rehydration method', followed by the 'extrusion technique' has shown to be superior over other procedures. In addition to many investigations in the field of cheese production--there are several studies on the (potential) medical and biomedical applications of enzyme-containing lipid vesicles (e.g. in the enzyme-replacement therapy or for immunoassays)--including a few in vivo studies. In many cases, the enzyme molecules are expected to be released from the vesicles at the target site, and the vesicles in these cases serve as the carrier system. For (potential) medical applications as enzyme carriers in the blood circulation, the preparation of sterically stabilized lipid vesicles has proven to be advantageous. Regarding the use of enzyme-containing vesicles as submicrometer-sized nanoreactors, substrates are added to the bulk phase. Upon permeation across the vesicle bilayer(s), the trapped enzymes inside the vesicles catalyze the conversion of the substrate molecules into products. Using physical (e.g. microwave irradiation) or chemical methods (e.g. addition of micelle-forming amphiphiles at sublytic concentration), the bilayer permeability can be controlled to a certain extent. A detailed molecular understanding of these (usually) submicrometer-sized bioreactor systems is still not there. There are only a few approaches towards a deeper understanding and modeling of the catalytic activity of the entrapped enzyme molecules upon externally added substrates. Using micrometer-sized vesicles (so-called 'giant vesicles') as simple models for the lipidic matrix of biological cells, enzyme molecules can be microinjected inside individual target vesicles, and the corresponding enzymatic reaction can be monitored by fluorescence microscopy using appropriate fluorogenic substrate molecules.

Development of the Baylor Gyro permanently implantable centrifugal blood pump as a biventricular assist device

The Baylor Gyro permanently implantable centrifugal blood pump (Gyro PI pump) has been under development since 1995 at Baylor College of Medicine. Excellent results were achieved as a left ventricular assist device (LVAD) with survival up to 284 days. Based on these results, we are now focusing on the development of a biventricular assist device (BVAD) system, which requires 2 pumps to be implanted simultaneously in the preperitoneal space. Our hypothesis was that the Gyro PI pump would be an appropriate device for an implantable BVAD system. The Gyro PI 700 pump is fabricated from titanium alloy and has a 25 ml priming volume, pump weight of 204 g, height of 45 mm, and pump diameter of 65 mm. This pump can provide 5 L/min against 100 mm Hg at 2,000 rpm. In this study, 6 half-Dexter healthy calves have been used as the experimental model. The right pump was applied between the infundibular of the right ventricle and the main pulmonary artery. The left pump was applied between the apex of the left ventricle and the thoracic descending aorta. As for anticoagulation, heparin was administered at the first postoperative week and then converted to warfarin sodium from the second week after surgery. Both pump flow rates were controlled maintaining a pulmonary arterial flow of less than 160 ml/kg/min for the sake of avoidance of pulmonary congestion. Blood sampling was done to assess visceral organ function, and the data regarding pump performance were collected. After encountering the endpoint, which the study could not keep for any reasons, necropsy and histopathological examinations were performed. The first 2 cases were terminated within 1 week. Deterioration of the pump flow due to suction phenomenon was recognized in both cases. To avoid the suction phenomenon, a flexible conduit attached on the inlet conduit was designed and implanted. After using the flexible inflow conduit, the required power and the rotational speed were reduced. Furthermore, the suction phenomenon was not observed except for 1 case. There was no deterioration regarding visceral organ function, and pulmonary function was maintained within normal range except for 1 case. Even though the experimental animal survived up to 45 days with the flexible inflow conduit, an increase in power consumption due to thrombus formation behind the impeller became a problem. Lower rotational speed, which was probably produced by the effectiveness of the flexible inflow conduit, was speculated to be one of the reasons. And the minimum range of rotational speed was 1,950 rpm in these 6 BVAD cases and the previous 3 cases of LVAD. In conclusion, 6 cases of BVAD implantation were performed as in vivo animal studies and were observed up to 45 days. The flexible inflow conduit was applied in 4 of 6 cases, and it was effective in avoiding a suction phenomenon. The proper rotational speed of the Gyro PI 700 pump was detected from the viewpoint of antithrombogenicity, which is more than 1,950 rpm.

Endoscopic sonography in the diagnosis of gallbladder wall lesions in patients with gallstones

PURPOSE

The purpose of this study was to evaluate the diagnostic accuracy of endoscopic sonography (EUS) in the detection of gallbladder wall lesions in patients with and without gallstones.

METHODS

We retrospectively reviewed the medical records, sonograms, and sonographic reports of 62 patients who underwent cholecystectomy for gallbladder wall lesions evaluated by EUS. We assessed the accuracy of EUS in diagnosing gallbladder wall lesions in the presence or absence of gallstones and on the basis of the size and number of stones and the size of the gallbladder wall lesions. We also evaluated the effect of acoustic shadowing. The EUS results were compared with the histopathologic results.

RESULTS

EUS correctly diagnosed the gallbladder wall lesions in 17 (71%) of 24 patients with gallstones and in 34 (89%) of 38 patients without gallstones. The diagnostic accuracy of EUS was 86% in patients with gallbladder wall lesions smaller than 20 mm and 79% in patients with gallbladder wall lesions 20 mm or larger. The diagnostic accuracy was 75% in patients with gallstones smaller than 5 mm and 67% in patients with stones 5 mm or larger. The accuracy was 67% in patients with 1-5 stones and 83% in patients with 6 or more stones. None of these differences was statistically significant. Acoustic shadowing did not affect the diagnostic accuracy of EUS.

CONCLUSIONS

The diagnostic accuracy of EUS for gallbladder wall lesions is not affected by the presence of gallstones. However, better diagnostic criteria must be established based on larger studies, and technical refinements of the equipment are needed to increase the accuracy of EUS in the diagnosis of gallbladder wall lesions.

Quantitative analysis of red color sign in the endoscopic evaluation of esophageal varices

BACKGROUND AND STUDY AIMS

Bleeding due to esophageal variceal rupture is associated with an extremely high mortality rate. Variceal bleeding is frequent in patients who have a red color sign on endoscopy. However, the red color sign is subjectively evaluated on the basis of color tone and the shape of the varices. To allow standardization and facilitate consensus, an objective method of assessing the red color sign is needed. In this study, a system was established for quantifying the red color sign during endoscopic evaluation.

PATIENTS AND METHODS

Between July 1995 and February 1997, 55 untreated patients with portal hypertension and esophageal varices identified on upper gastrointestinal endoscopy were enrolled in the study. Images obtained about 5 cm oral to the esophagogastric junction during endoscopy were stored on magnetic optical disks using an endoscopic image processor. The still images were transmitted to a computer and analyzed using computer software. The RGB components (R, red; G, green; B, blue) were measured at points showing flare consistent with the red color sign. The endoscopic assessment was based on the Japanese Research Society for Portal Hypertension's general rules for recording endoscopic findings in esophagogastric varices.

RESULTS

The ratio of the red color area to the variceal area increased with increasing red color grade. There were significant positive correlations between the R and G, and G and B components. This suggests that comparing the R components alone would allow assessment of the color differences in the red color area and in the varices. The R value was significantly higher in the red color area (115 +/- 20) than in the varices (57 +/- 19). An R value of 90 was found at the boundary between the two parts (P < 0.001).

CONCLUSIONS

The red color area can be automatically calculated and quantified using the analysis program. Improvements in data storage methods may allow real-time evaluation during endoscopy in the future.

Blood trauma induced by clinically accepted oxygenators

Hemolysis remains one of the most serious problems during cardiopulmonary bypass (CPB), extracorporeal membrane oxygenation (ECMO), and percutaneous cardiopulmonary support (PCPS). However, the hemolytic characteristics associated with oxygenators are not well defined. A specialized hemolysis test protocol for oxygenators was developed. A comparative study was performed following this protocol to determine the hemolytic characteristics of the clinically available oxygenators during CPB; pressure drop measurements in the blood chamber were also performed. Four oxygenators (Medtronic Affinity, Cobe Optima, Terumo Capiox SX25, and Bard Quantum) were evaluated. Fresh blood from healthy Dexter calves anticoagulated with citrate phosphate dextrose adenine solution was used. The blood flow was fixed at 5 L/min, similar to that used in CPB. The Normalized Index of Hemolysis for Oxygenators (NIHO) has been modified according to the American Society of Testing and Materials (ASTM) standards. The NIH value, which was obtained from the circuit without an oxygenator, was subtracted from the primary NIH value, obtained from the circuit with an oxygenator to eliminate the effects of a centrifugal pump or other artifacts. The NIHO value was the lowest in the Affinity (0.0116 +/- 0.0017) and increased from Affinity < Optima (0.0270 +/- 0.0038) < Capiox (0.0335 +/- 0.0028) < Quantum (0.0416 +/- 0.0015 g/100 L). The Optima and Capiox did not demonstrate a significant difference. In addition, this NIHO value has a close relationship to the pressure drop. In conclusion, this new evaluation method is suitable to compare the biocompatibility performance of different types of clinically available oxygenators for CPB usage.

Partial median sternotomy as a minimal access for off-pump coronary artery bypass grafting: feasibility of the lower-end sternal splitting approach

BACKGROUND

Off-pump coronary artery bypass grafting (OPCAB) can be performed in several ways using a minimally invasive approach (MIDCAB). Using the left anterior small thoracotomy (LAST) approach, only the LAD can be grafted. To expand the indications for MIDCAB from single-vessel disease to double-vessel disease, we have used a partial sternotomy without a transverse cut, namely, the lower-end sternal splitting (LESS) approach. Through this approach, the LAD and RCA can be revascularized by means of a single small incision without the risk of damaging the tissue around the intercostal space during harvesting of ITA when the sternum is transversely divided. The purpose of this study was to demonstrate the feasibility and safety of this technique.

METHODS

Between November 1999 and November 2000, a total of 22 patients underwent MIDCAB through a lower midline skin incision from the fourth intercostal space to the xiphoid process with longitudinal division of the lower half sternum up to the 3rd rib, without either a T- or reversed L-shaped division of the sternum. Of the patients, 14 had LAD disease only, 5 had both LAD and RCA disease, 2 had RCA disease only, and 1 had left main trunk disease. Two of the operations were of redo coronary artery bypass grafting. The mean age was 69.5 +/- 6.1 years (range 58 to 77 years).

RESULTS

The mean length of the skin incision was 8.5 +/- 1.4 cm (range 7 to 12 cm). No hospital death or morbidity was observed. All patients had arterial conduits: LIMA in 20 patients, RIMA in 3, RGEA in 4, and RA in 1. The mean number of grafts per patient was 1.3 +/- 0.6 (range 1 to 3). No blood transfusion was required perioperatively. The patency rate was 96%. All patients were in New York Heart Association class I and no wound complications or postoperative pain occurred during follow-up.

CONCLUSIONS

Our experience demonstrates that the LESS approach for MIDCAB is technically feasible for revascularizing not only the LAD but also the RCA system, with the same small incision using IMA and GEA. It can be used with excellent cosmetic results and safety. Although our experience is limited, we conclude that this less invasive surgical technique can be used as an alternative approach for MIDCAB in patients with LAD or RCA disease.

Positive correlation between circulating leptin levels and lipid lipoproteins in postmenopausal women administered hormone replacement therapy

Beneficial effects of hormone replacement therapy are reported on plasma concentrations of lipids and lipoproteins. Plasma leptin levels are reported to reflect lipid metabolism. We treated 40 healthy postmenopausal women with continuous combined HRT (0.625 mg conjugated equine estrogen and 2.5 mg medroxyprogesterone acetate orally) daily for 6 months and then investigated total cholesterol, triglyceride, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol, which are considered to be factors inducing cardiovascular disease (CVD). We measured the plasma levels of lipids and leptin, which are considered to be altered with HRT. Plasma leptin and lipid levels were measured at baseline and after 3 and 6 months of HRT. The plasma levels of leptin in PMW were not significantly reduced by HRT. Although the plasma levels of total cholesterol and LDL-cholesterol did not change by HRT, the administration of HRT significantly increased plasma levels of triglycerides and HDL-cholesterol in PMW. The correlation between leptin and total cholesterol or triglycerides was positive after HRT while these relations were not correlated at baseline. The correlation between lipid levels and leptin may explain the new role of leptin in plasma lipid levels in HRT.

Karyotypes and Giemsa C-banding patterns of Zebrina pendula, Z. purpusii and Setcreasea purpurea, compared with those of Tradescantia ohiensis

It has been proposed that the genera Zebrina and Setcreasea of the family Commelinaceae should be united and reunited, respectively, with the genus Tradescantia, mainly based on morphological studies. In the present study, karyotypes and Giemsa C-banding patterns in the root-tip cells of three Zebrina and two Setcreasea clones were analyzed, and were compared with those of a triploid Tradescantia clone. Z. pendula and Z. purpusii (both 2n = 24) were found to have similar karyotypes (4 M + 6 ST + 14 T; M = meta-, ST = subtelo-, T = telocentric chromosomes), while Z. pendula cv Quadricolor (2n = 23) had a unique karyotype (6 M + 5 ST + 11 T + 1 SA; SA = short acrocentric chromosome). The only clear difference between Z. pendula and Z. purpusii was that one and two subtelocentric chromosomes, respectively, had satellites at the short arms. Two clones of S. purpurea (2n = 24) had karyotypes (8 M + 8 M' + 8 SM; M' = nearly meta-, SM = submetacentric chromosomes) similar to each other. T. ohiensis (2n = 18) had a symmetric karyotype (9 M + 9 SM) consisting of larger chromosomes than S. purpurea. Many clear Giemsa C-bands were detected, in addition to centromeric bands in all chromosomes of all clones. Z. pendula and Z. purpusii commonly had single clear interstitial bands in eight telocentric chromosomes each, but they also had unique telomeric and other interstitial bands, respectively. Z. pendula cv Quadricolor had a unique banding pattern, i.e., satellite bands in the unique short chromosome, telomeric bands at the long arms of all metacentric chromosomes, and single interstitial bands in six telocentric chromosomes. Two clones of S. purpurea had telomeric bands at many chromosome arms and satellite bands in two nearly metacentric and one submetacentric chromosomes, but some differences were found between them. On the other hand, all the chromosomes of T. ohiensis had telomeric bands at both arms, and three submetacentric chromosomes had satellite bands. These result prove structural differentiation of chromosomes occurred among the clones, especially in Zebrina, and show that S. purpurea is relatively close to T. ohiensis, while Zebrina is obviously distant from the other two genera. Therefore, there remains a question cytologically at least for uniting Zebrina with Tradescantia.

Effects of double mutation at two distant IgE-binding sites in the three-dimensional structure of the major house dust mite allergen Der f 2 on IgE-binding and histamine-releasing activity

Recently, we reported that introduction of mutations that induced conformational changes of the major mite allergen Der f 2 was an efficient strategy to reduce the allergenicity for safer allergen-specific immunotherapy. In this study, we evaluated another strategy, disruption of two independent IgE epitopes without inducing conformational change. We analyzed allergenicities of the wild-type Der f 2, two single mutants with a mutation at either of the two IgE-binding sites (K15A and K77A), and a double mutant with mutations at both of the sites (K15/77A). Purified recombinant forms of Der f 2 expressed in Escherichia coli had correct disulfide bonds, equivalent apparent molecular masses of approximately 15 kDa, and similar secondary structures. The mutants of Der f 2 had less IgE reactivities than the wild-type Der f 2 and reduced inhibitory activities for IgE-binding to the wild-type Der f 2. However, the mutations did not significantly reduce histamine-releasing activity.

Developmental patterns of ceramide glucosyltransferase (GlcT-1) expression in the mouse: in situ hybridization using DIG-labeled RNA probes

Glycosphingolipids (GSLs) play significant roles in a variety of cell membrane events, including cellular interactions, signaling, and trafficking. Ceramide glucosyltransferase (glucosylceramide synthase, GlcT-1, EC 2.4.1.80) catalyzes the initial step in GSL synthesis, the transfer of glucose from UDP-glucose to ceramide. The reaction product of glucosylceramide serves as a core structure for over 400 species of GSLs. The enzyme is a key regulatory factor controlling intracellular levels of ceramide and GSLs. Appearance and differential distribution of GlcT-1 mRNA during mice postimplantation embryogenesis [embryonic (E) days; E9, E11, E13, E15] were investigated by in situ hybridization with digoxigenin-labeled RNA probes, coupled with alkaline phosphatase detection. On E9, tissues of the mesencephalon, myelecephalon, diencephalons, and telencephalon expressed GlcT-1. On E11, it was expressed to a detectable extent in various tissues including mesencephalon, myelecephalon, diencephalon, telencephalon, nose, lung, liver, vertebra, tail, spinal cord, and tongue. The expression patterns of E13 were similar to those of E11, except that the heart and stomach became positive. On E15, a specific signal for GlcT-1 was detected in all organs of the embryo. These results provide the first evidence that GlcT-1 is differentially expressed during postimplantation embryogenesis.

beta-estradiol 3-benzoate affects spermatogenesis in the adult mouse

beta-estradiol 3-benzoate (E(2)B) (10, 16, 20, 40, 80 and 160 microg/kg body weight) was administered daily to experimental groups of adult mice for the following periods; 2, 3 days, 1, 2, 4, and 8 weeks. Morphological changes in the testes were observed by both light and electron microscopy. Exfoliation of the germ cells was observed in the lumen of the seminiferous tubule. The spermatogenic cycle, especially stage XII, was disordered. Spermatids older than step 6 were severely affected. Detected abnormalities in the spermatids were deformation of the nucleus and acrosome. Partial deletion in the Sertoli-spermatid ectoplasmic specialization was also observed. Germ cells younger than step 7 spermatids were not affected morphologically. These abnormalities were not detected in the mice treated with the chemical at less than 16 microg/kg body weight. It is concluded that the chemical seems to affect round spermatids metabolically, but the morphological effect can be detected only from the spermatids older than step 6. The effects of the chemical on adult mice were reversible.

Coexistence of lung cancer and hamartoma

We present a rare case of a synchronous primary lung cancer adjacent to a hamartoma. A 71-year-old woman was admitted with congestive heart failure due to acute myocardial infarction. A chest radiogram on admission showed pulmonary edema with a tumor shadow in the right upper lung field. Because histological diagnosis was not obtained preoperatively, a wedge resection of the lung was conducted using video-assisted thoracoscopic surgery. The histopathological examination confirmed the coexistence of an adenocarcinoma with a chondromatous hamartoma. Right upper lobectomy was performed followed by excision of the mediastinal lymph nodes. Although hamartoma is generally considered to be a benign neoplasm, there have been several reports of increased risk to lung cancer in patients with a chondromatous hamartoma. Therefore, we recommend that patients with a hamartoma should be submitted to a complete evaluation and to regular follow-up, considering the risk to associated synchronous malignancy.

Development of a new hollow fiber silicone membrane oxygenator: in vitro study

An experimental silicone hollow fiber membrane oxygenator for long-term extracorporeal membrane oxygenation (ECMO) was developed in our laboratory using an ultrathin silicone hollow fiber. However, the marginal gas transfer performances and a high-pressure drop in some cases were demonstrated in the initial models. In order to improve performance the following features were incorporated in the most recent oxygenator model: increasing the fiber length and total surface area, decreasing the packing density, and modifying the flow distributor. The aim of this study was to evaluate the gas transfer performances and biocompatibility of this newly improved model with in vitro experiments. According to the established method in our laboratory, in vitro studies were performed using fresh bovine blood. Gas transfer performance tests were performed at a blood flow rate of 0.5 to 6 L/min and a V/Q ratio (V = gas flow rate, Q = blood flow rate) of 2 and 3. Hemolysis tests were performed at a blood flow rate of 1 and 5 L/min. Blood pressure drop was also measured. At a blood flow rate of 1 L/min and V/Q = 3, the O2 and CO2 gas transfer rates were 72.45 +/- 1.24 and 39.87 +/- 2.92 ml/min, respectively. At a blood flow rate of 2 L/min and V/Q = 3, the O2 and CO2 gas transfer rates were 128.83 +/- 1.09 and 47.49 +/- 5.11 ml/min. Clearly, these data were superior to those obtained with previous models. As for the pressure drop and hemolytic performance, remarkable improvements were also demonstrated. These data indicate that this newly improved oxygenator is superior to the previous model and may be clinically acceptable for long-term ECMO application.

Gas transfer performance of a hollow fiber silicone membrane oxygenator: ex vivo study

Based on the results of in vitro studies of many experimental models, a silicone hollow fiber membrane oxygenator for pediatric cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) was developed using an ultrathin silicone hollow fiber with a 300 microm outer diameter and a wall thickness of 50 microm. In this study, we evaluated the gas transfer performance of this oxygenator simulating pediatric CPB and ECMO conditions. Two ex vivo studies in a pediatric CPB condition for 6 h and 5 ex vivo studies in an ECMO condition for 1 week were performed with venoarterial bypass using healthy calves. At a blood flow rate of 2 L/min and V/Q = 4 (V = gas flow rate, Q = blood flow rate) (pediatric CPB condition), the O2 and CO2 gas transfer rates were maintained at 97.44 +/- 8.88 (mean +/- SD) and 43.59 +/- 15.75 ml/min/m2, respectively. At a blood flow rate of 1 L/min and V/Q = 4 (ECMO condition), the O2 and CO2 gas transfer rates were maintained at 56.15 +/- 8.49 and 42.47 +/- 9.22 ml/min/m2, respectively. These data suggest that this preclinical silicone membrane hollow fiber oxygenator may be acceptable for both pediatric CPB and long-term ECMO use.

[Effect of olopatadine hydrochloride, a novel antiallergic agent, on the QT interval in dogs]

Olopatadine hydrochloride (olopatadine), a novel antiallergic agent, is effective in the treatment of allergic rhinitis, chronic urticaria, eczema and dermatitis. It has been reported that terfenadine and astemizole cause side effects on the circulatory system such as QT prolongation followed by serious ventricular arrhythmias (torsades de pointes). To investigate the possibility of QT prolongation, we used both conscious normal dogs and hypokalemia-anesthetized dogs under two conditions: 1) olopatadine used alone and 2) olopatadine used in combination with itraconazole, the CYP3A4-inhibiting antifungal agent, in the present investigation. The group treated with terfenadine alone (30 mg/kg, p.o.) and the group treated with a combination of terfenadine (10 mg/kg, p.o.) and itraconazole (100 mg/kg, p.o.) had a significantly prolonged QT interval. On the other hand, the group treated with olopatadine alone (30 mg/kg, p.o.) and the group treated with a combination of olopatadine (30 mg/kg, p.o.) and itraconazole (100 mg/kg, p.o.) did not show any significant changes in QT interval. Moreover, olopatadine (1 and 5 mg/kg, i.v.) did not influence the QT interval in hypokalemia-anesthetized dogs. These results suggest that there is very little possibility of QT prolongation as a result of clinically used olopatadine.

Further yearly analyses of spontaneous pink mutant events in the stamen hairs of tradescantia clone BNL 4430 cultivated in the NSC growth chamber

In order to confirm the results obtained in the previous 1-year-term (December 12, 1998, through December 10, 1999) scorings and analyses of spontaneous pink mutant events (PMEs) in the stamen hairs of Tradescantia clone BNL 4430 cultivated in a nutrient solution circulating (NSC) growth chamber, similar scorings and analyses were continued for another 52-week period from December 11, 1999, through December 8, 2000. The environmental conditions were not changed, except for a minor modification in the method of supplying the nutrient solution used. During the scoring period, 732,128 stamen hairs with an average cell number of 24.90 cells were observed, and 2,368 PMEs were detected. The overall spontaneous somatic mutation frequency was 1.35 +/- 0.03 PMEs per 10(4) hair-cell divisions, which was significantly lower than the value of 1.56 +/- 0.03 determined in the previous 52-week period, and the frequencies were lower during April through September than in other months, the period showing lower frequencies lasting 1-month longer than in the previous year. The present results reconfirmed the occurrence of a clear seasonal variation in the spontaneous mutation frequency in the NSC growth chamber, and the lower overall frequency, probably related to the minor modification in supplying the nutrient solution, is helpful for conducting mutagenicity tests at low levels, offering a lower background level. The analyses of the sectoring patterns of all these PMEs showed that the most of the 203 cases of multiple (two to five) pink sectors observed in the same stamen hairs (scored as 253 PMEs for calculating mutation frequency) were the results of events involving somatic recombinations occurred in single cells or cell lineages, rather than those of two or more independent somatic mutations occurred in different cells, agreeing with our previous study, and the significance of somatic recombinations in causing single PMEs was also reconfirmed.

Total synthesis of fostriecin (CI-920)

The first total synthesis of the potent antitumor agent fostriecin (CI-920) is described, confirming the relative and absolute stereochemistry assignments. Fostriecin is a unique phosphate monoester which exhibits weak topoisomerase II inhibition (IC(50) = 40 microM) and more potent and selective protein phosphatase 2A and 4 (PP2A and PP4) inhibition (IC(50) = 40-3 nM and 1.5 nM), resulting in mitotic entry checkpoint inhibition. Phase I clinical trials with fostriecin, which were the first to explore the potential of this novel mechanism of action, were halted even before therapeutic concentrations were reached or dose-limiting toxicity established due to problems of drug stability observed during storage of naturally derived material. The synthesis of fostriecin detailed herein is the first stage of efforts that may serve to address these limitations to the clinical examination of this or related promising new antitumor agents.