Myocardial protection with pinacidil induced hyperpolarized arrest during cardiopulmonary bypass

OBJECTIVE

To investigate the myocardial protective effects of pinacidil-induced hyperpolarized arrest and compare with those afforded by conventional depolarized hyperkalemic arrest.

METHODS

Eighteen dogs were equally divided into three groups: normothermic hyperpolarized group (Group A), hypothermic hyperpolarized group (Group B), and hyperkalemic group (Group C). Pinacidil (50 mumol/L) containing 37 degrees C St. Thomas solution (K+ 5 mmol/L, 10 ml/kg), pinacidil (50 mumol/L, Sigma, USA) containing 4 degrees C St. Thomas solution (K+ 5 mmol/L, 10 ml/kg) and 4 degrees C standard St. Thomas solution (K+ 16 mmol/L, 10 ml/kg) were infused respectively through the aortic root after aortic-clamping. Heart arrest and its recovery, ultrastructure of the myocardium, the level of serum myocardial enzymes, and lipid peroxide and adenine nucleotide of the myocardium were measured. Hemodynamics during ischemia and after reperfusion were observed.

RESULTS

The percentages of normal mitochondria and glycogen did not change much during ischemia (except at 60 min) and after reperfusion in B Group, but declined markedly in Group C 30 min and 60 min after ischemia and 20 min after reperfusion (P < 0.01). In Group A, they were lower than those of Group B before ischemia, but higher than those of Group C. The recoveries of CO, SV, CI, LVSW, RVSW and MAP in Group B were significantly better than those in other two groups 15 min and 30 min after reperfusion (P < 0.05 and 0.01, respectively). However, they were still better in Group A than those in Group C (P < 0.05 and 0.01, respectively). The onset of heart arrest was faster in Groups C and B than that in Group A. Highly elevated serum myocardial enzymes were observed 60 min after ischemia and 20 min after reperfusion in Group C, while they were only mild in the hyperpolarized groups, especially in Group B, and their recoveries were rapid. Adenine nucleotides of the myocardium were better preserved in Group B than in other two groups 30 min, 60 min after ischemia, and 20 min after reperfusion (P < 0.05 and 0.01, respectively). They were also much better in Group A than in Group C (P < 0.05 and 0.01, respectively). Lipid peroxide of the myocardium were significantly lower in Group B than in other groups 20 min after reperfusion (P < 0.01), and they were lower in Group A than in Group C (P < 0.05).

CONCLUSIONS

Myocardial protection for global ischemia during cardiopulmonary bypass (CPB) could be achieved with hyperpolarized heart arrest induced by pinacidil, an ATP-sensitive potassium channel opener, especially in the hypothermic state. The protection is weaker in normothermia but is still superior to that with traditional depolarized hyperkalemic arrest.

Influence of BOL on hyaluronic acid, laminin and hyperplasia in hepatofibrotic rats

AIM

To study the anti-hepatofibrosis mechanism of Bie Jia Jian oral liquid (BOL).

METHODS

The model was induced by subcutaneous injection of CCl(4). BOL was administered and the change of serum hyaluronic acid (HA) and laminin (LN) was observed and the degeneration of liver cells and the degree of fibre hyperplasia analyzed. Changes of ultra micro-structure in liver cells were observed in some samples.

RESULTS

HA was reduced in both the groups with low and high dosage of BOL, which showed a remarkable difference as compared with that of the model group (low dosage group: 376.15 microg/L+/-35.48 microg/L vs 806.07 microg/L+/-98.49 microg/L P<0.05; high dosage group: 340.14 microg/L+/-30.18 microg/L vs 806.07 microg/L+/-98.49 microg/L P<0.05). The LN content of low and high dosage group of BOL was lower than that of model group (low dosage group: 71.99 microg/L+/-8.15 microg/L vs 133.94 microg/L+/-14.45 microg/L P <0.01; high dosage group: 71.68 microg/L+/-11.62 microg/L vs 133.94 microg/L+/-14.45 microg/L P<0.01) and colchicine group (low dosage group: 71.99 microg/L+/-8.15 microg/L vs 118.28 microg/L+/-16.13 microg/L P < 0.05; high dosage group: 71.68 microg/L+/-11.62 microg/L vs 118.28 microg/L+/-16.13 microg/L P <0.05). Examined by Ridit, BOL could reduce the degeneration and necrosis of liver cells (chi(2)=11.99 P<0.05), the degree of fibre hyperplasia (chi(2)=13.24 P<0.05) and the pathological change of ultra micro-structure as well.

CONCLUSION

The BOL has certain therapeutic effect on the experiment hepatofibrosis. Its mechanisms might include: protecting the function of liver cells, inhibiting excessive synthesis and secretion of extracellular matrix from hepatic stellate cells, relieving the capillarization of hepatic sinusoid, improving liver micro-circulation, and regulating immune function.

The natural silk spinning process. A nucleation-dependent aggregation mechanism?

The spinning mechanism of natural silk has been an open issue. In this study, both the conformation transition from random coil to beta sheet and the beta sheet aggregation growth of silk fibroin are identified in the B. mori regenerated silk fibroin aqueous solution by circular dichroism (CD) spectroscopy. A nucleation-dependent aggregation mechanism, similar to that found in prion protein, amyloid beta (Abeta) protein, and alpha-synuclein protein with the conformation transition from a soluble protein to a neurotoxic, insoluble beta sheet containing aggregate, is a novel suggestion for the silk spinning process. We present evidence that two steps are involved in this mechanism: (a) nucleation, a rate-limiting step involving the conversion of the soluble random coil to insoluble beta sheet and subsequently a series of thermodynamically unfavorable association of beta sheet unit, i.e. the formation of a nucleus or seed; (b) once the nucleus forms, further growth of the beta sheet unit becomes thermodynamically favorable, resulting a rapid extension of beta sheet aggregation. The aggregation growth follows a first order kinetic process with respect to the random coil fibroin concentration. The increase of temperature accelerates the beta sheet aggregation growth if the beta sheet seed is introduced into the random coil fibroin solution. This work enhances our understanding of the natural silk spinning process in vivo.

Neurotransmitter dopamine applied in electrochemical determination of aluminum in drinking waters and biological samples

It was demonstrated that the decrease of the differential pulse voltammetric (DPV) anodic peak current of dopamine (3,4-dihydroxyphenylethylamine, DA) was linear with the increase of aluminum (Al) concentration. Under optimum experimental conditions (pH 4.6, 1.2 x 10(-3) M DA, and 0.04 M NaAc-HAc buffer solution), the linear range is 4.0 x 10(-7)-8.0 x 10(-5) M, the detection limit is 1.4 x 10(-7) M, and the relative standard deviation for 4 x 10(-5) M Al(III) is 3.5% (n=8). Many foreign species, especially some low-molecule-weight biological molecules, were chosen for interference testing. The proposed method was applied to the determination of Al in biological samples such as synthetic renal dialysate, Ringer's solution, human blood, cerebrospinal fluid of a patient, and urine of a diabetic patient. The corresponding recoveries were generally between 95 and 105%. The basic principle of the method was determined by examining Al complexed with DA. This results in the blockage of the electroactive sites on DA, followed eventually by the reduction of the electrochemical response of DA. This result was verified by examining the behavior of DA, both in the presence and absence of Al, using electrochemical, UV-Vis, Raman, and (13)C NMR spectroscopic methods.

Women's decision-making determinants in choosing uterine artery embolization for symptomatic fibroids

OBJECTIVE

To determine what symptoms of leiomyomata uteri prompted women to seek uterine artery embolization (UAE) and what factors were most frequently cited in the decision making leading to choosing UAE over other treatments.

STUDY DESIGN

Eighty-four consecutive women with symptomatic leiomyoma presenting for UAE completed a questionnaire that inquired about their pelvic symptoms and the issues that were important in their decision to request UAE. All subjects previously had been told that they were surgical candidates.

RESULTS

Pelvic symptoms that the 84 women most frequently noted were bleeding (n = 61), anemia (41), pelvic pain (29), frequent urination (24) and pelvic pressure (21). The majority of women (78) reported significant worry about their health from the fibroids, and (72) reported that the symptoms caused daily discomfort. Although the majority of women wanted a treatment that would give permanent relief of symptoms and thought UAE would do this, other factors frequently cited in the decision making included quality-of-life reasons, such as the desire to avoid adverse effects of other treatments (76), anticipated prolonged postoperative recovery from surgery (70) and avoiding surgery (66). Many women considered the uterus an important female organ, believed that the uterus was a source of femininity (33), stated that the uterus was necessary to maintain self-image (49) and reported that the uterus was necessary to maintain sexual image (49).

CONCLUSION

In this cohort of women with symptomatic leiomyomas, treatment preferences did not interfere with the current lifestyle. In addition, the uterus was considered a source of femininity and sexuality. It is not clear whether women requesting UAE differ from women requesting surgical intervention in terms of how they assess the importance of the uterus, but these data suggest that many women still consider the uterus an important aspect of their femininity and that those seeking nonsurgical options should be thoroughly counseled about uterine function and how it relates to sexuality.

Disruption of protein-protein interactions: design of a synthetic receptor that blocks the binding of cytochrome c to cytochrome c peroxidase

Synthetic receptor 1 has been found via fluorescence titration to compete effectively with cytochrome c peroxidase for binding cytochrome c (Cc), forming 1:1 Cc:1 complex with a binding constant of (3 +/- 1) x 10(8) M-1, and to disrupt Cc: Apaf-1 complex, a key adduct in apoptosis.

Characterization of the interaction between the dark septate fungus Phialocephala fortinii and Asparagus officinalis roots

Phialocephala fortinii Wang & Wilcox is a member of root-inhabiting fungi known collectively as dark septate endophytes (DSE). Although very common and distributed worldwide, few studies have documented their interaction with roots on a structural basis. The objective of this study was to determine the early colonization events and formation of microsclerotia of P. fortinii in roots of Asparagus officinalis L., a species known to have DSE. A loose network of hyphae accumulated at the root surface, and coils formed around root hairs and external to epidermal cells overlying short cells of the dimorphic, suberized exodermis. Root penetration occurred via swollen, appressorium-like structures into epidermal cells where coiling of hyphae occurred along the periphery of the cells. Hyphae penetrated from the epidermis into short exodermal cells and from these into cortical cells. Hyphae colonized the cortex up to the endodermis and sometimes entered the vascular cylinder. Some root tips were colonized as well. Microsclerotia in epidermal and exodermal short cells accumulated glycogen, protein, and polyphosphate. Energy-dispersive X-ray spectroscopy on distinct bodies visible in microsclerotial hyphae revealed high levels of phosphorus.

D609 inhibits ionizing radiation-induced oxidative damage by acting as a potent antioxidant

Tricyclodecan-9-yl-xanthogenate (D609) has been extensively studied in biological systems and exhibits a variety of biological functions, including antiviral, antitumor, and anti-inflammatory activities. Most of these activities have been largely attributed to the inhibitory effect of D609 on phosphatidylcholine-specific phospholipase C. However, as a xanthate derivative, D609 is a strong electrolyte and readily dissociates to xanthate anions and cations of alkali metals in solution. Xanthate anions and protonated xanthic acid contain a free thiol moiety and are highly reductive. This implies that D609 and other xanthate derivatives may function as potent antioxidants. Indeed, we found that D609 inhibited the Fenton reaction-induced oxidation of dihydrorhodamine 123 in a dose-dependent manner similar to that of pyrrolidinedithiocarbamate, a well known antioxidant. In addition, D609 inhibited the formation of the alpha-phenyl-tert-butylnitrone-free radical spin adducts and lipid peroxidation of synaptosomal membranes by the Fenton reagents. Furthermore, preincubation of lymphocytes with D609 resulted in a significant diminution of ionizing radiation (IR)-induced 1) production of reactive oxygen species; 2) decrease in intracellular reduced glutathione; 3) oxidative damage to proteins and lipids; and 4) activation of nuclear factor-kappaB. Moreover, when D609 (50 mg/kg i.v.) was administered to mice 10 min prior to total body IR (6.5 and 8.5 Gy), it protected the mice from IR-induced lethality. Thus, these results indicate that D609 is a potent antioxidant and has the ability to inhibit IR-induced cellular oxidative stress.

Effects of NF-kappaB1 (p50) targeted gene disruption on ionizing radiation-induced NF-kappaB activation and TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo

PURPOSE

To investigate the role of the NF-kappaB1 (p50) gene in ionizing radiation (IR)-induced NF-kappaB activation and TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo.

MATERIALS AND METHODS

NF-kappaB activation was analysed by the gel shift/supershift assay and the levels of TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA were measured using RNase protection assay (RPA). Various tissues from BALB/c, B6,129P-Nfkb1 (NF-kappaB1 or p50 gene knockout, p50(-/-)) and B6,129PF2 (wild-type, p50(+/+)) mice were analysed before or after exposure to a lethal dose (8.5 Gy) of total-body gamma-irradiation.

RESULTS

Exposure of BALB/c mice to total-body IR selectively activated NF-kappaB in the spleen, mesenteric lymph nodes (LN) and bone marrow (BM). Gel supershift assay using polyclonal antibodies against NF-kappaB p50, p65 or c-Rel protein revealed that the NF-kappaB p50 subunit is a critical component of the NF-kappaB complexes activated by IR in vivo. Discretely augmented TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression was found in the spleen, LN and BM after BALB/c mice received IR. However, mice lacking the p50 gene (p50(-/-)) showed a significant reduction in IR-induced activation of NF-kappaB and increases in TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression, as compared with that of wild-type mice (p50(+/+)).

CONCLUSIONS

The NF-kappaB p50 subunit is a critical component of the NF-kappaB complexes activated by IR and it plays an important role in mediating IR-induced TNFalpha, IL-1alpha, IL-1beta and IL-6 mRNA expression in vivo.

[The expression of uridine diphosphate glucuronosyltransferase mRNA regulated by alcohol]

OBJECTIVE

To investigate whether ethanol and isopentanol could modulate the drug metabolism by regulating uridine diphosphate glucuronosyltransferase (UGT) expression in rat livers and cultured rat hepatocytes.

METHODS

Rat livers and primary rat hepatocyte cultures have been used to determine the mRNA levels of five UGT isoenzymes following treatment with ethanol and isopentanol.

RESULTS

Following treatment with alcohol in rats, UGT1A1 mRNA and UGT1A5 mRNA were increased to a mean of 177% and 166% of control, respectively. The mRNA levels of UGT2B1 and UGT2B3 were also increased in alcohol-treated rats to 178% and 132% of control, respectively. Incubation of hepatocytes with ethanol and isopentanol significantly increased the mRNA expression of UGT1A1, UGT1A5, UGT2B1 and UGT2B3 mRNA.

CONCLUSIONS

The expression of UGT can be regulated by ethanol and isopentanol. As a result, chronic alcohol consumption may modify the metabolism of numerous endogenous and exogenous compounds, in particular some drugs, which are substrates of these UGT isoenzymes.

Contemporary treatment of thrombosed hemodialysis grafts

Maintaining hemodialysis grafts remains a difficult problem. Before the early 1990s, graft declotting was usually performed in the surgical suite. Percutaneous declotting has been evolving since the mid-1980s. Initially, a low-dose thrombolytic infusion of streptokinase through a single catheter was used. Crossing catheters with a higher-dose infusion of urokinase was then introduced. This technique was modified with the adjunctive use of pharmacomechanical techniques with the use of compliant balloons and the adjunctive use of heparin. The advent of the "lyse-and-wait" technique provided a simpler and quicker way to declot thrombosed grafts by using urokinase, with similar outcomes. Since the removal of urokinase from the market, multiple mechanical devices have been used with similar success. Recent reports concerning the use of newer-generation thrombolytic agents report similar outcomes, with a reduction in total cost.

Potentiation of cytotoxicity of adriamycin on human ovarian carcinoma cell line 3AO by low-level ultrasound

The aim of this study was to determine whether the ultrasound, with a dosage that did not lead to acute and delayed inhibition, could potentiate the cytotoxicity of adriamycin to human ovarian carcinoma cell line 3AO in vitro. Drug sensitivity was analyzed by clonogenic assay, cells were treated by adriamycin singly in group ADM (control), adriamycin prior to ultrasound exposure in group ADM + US, and ultrasound irradiation prior to adriamycin administration in group US + ADM. The intracellular drug accumulation in each group was determined by fluorometry. The results were: (1) the values of IC50 were 0.0083, <0.001 and 0.0065 microg/ml in group ADM, ADM + US and US + ADM respectively; the clone surviving rate in group ADM + US and in group US + ADM were decreased (P < 0.001, P < 0.01), compared with control; the surviving rate in group ADM + US was lower than that in group US + ADM (P < 0.01). (2) The intracellular drug accumulations in group ADM + US were promoted (P < 0.01) and not increased significantly in group US + ADM (P > 0.05). These suggested that the low-level ultrasound could enhance the cytotoxicity of adriamycin to human ovarian carcinoma cells and promoted intracellular drug contents played the leading role.

Using computerized data to identify adverse drug events in outpatients

OBJECTIVE

To evaluate the use of a computer program to identify adverse drug events (ADEs) in the ambulatory setting and to evaluate the relative contribution of four computer search methods for identifying ADEs, including diagnosis codes, allergy rules, computer event monitoring rules, and text searching.

DESIGN

Retrospective analysis of one year of data from an electronic medical record, including records for 23,064 patients with a primary care physician, of whom 15,665 actually came for care.

MEASUREMENT

Presence of an ADE; sensitivity and specificity of computer searches for ADE.

RESULTS

The computer program identified 25,056 incidents, which were associated with an estimated 864 (95 percent confidence interval [CI], 750-978) ADES. Thus, the ADE rate was 5.5 (CI, 5.2-5.9) per 100 patients coming for care. Furthermore, in 79 (CI, 68-89) ADEs, the patient required hospitalization, resulting in an estimated rate of 3.4 (CI, 2.7-4.3) admissions per 1,000 patients. The sensitivity of the search methods for identifying ADEs was estimated to be 58 (CI, 18-98) percent, and the estimated specificity was 88 (CI, 87-88) percent. The positive predictive value was 7.5 (CI, 6.5-8.5) percent, and the negative predictive value was 99.2 (CI, 95.5-99.98) percent. Compared with age and gender-matched controls with no positive screen, patients with ADEs had twice as many outpatient visits and were taking nearly three times as many drugs. Antihypertensives, ACE-inhibitors, antibiotics, and diuretics were associated with 56 (CI, 47-65) percent of ADES. Among ADEs, 23 (CI, 16-32) percent were life-threatening or serious, and 38 (CI, 29-47) percent were judged preventable.

CONCLUSION

Computerized search programs can detect ADEs, and free-text searches were especially useful. Adverse drug events were frequent, and admissions were not rare, although most hospitals today do not identify them. Thus, such detection programs demonstrate "value-added" for the electronic record and may be useful for directing and assessing the impact of quality improvement efforts.

Stratification and oxidation-reduction potential change in an aerobic and sulfate-reducing biofilm studied using microelectrodes

Recent studies in aerobic-nitrifying biofilms demonstrated the heterogeneity of biofilms used in wastewater treatment and led to modifications of the homogeneous assumptions in the conventional biofilm kinetic models. However, the stratification in aerobic-anaerobic biofilms has not been well investigated because of a lack of effective experimental tools. In this study a suite of microelectrodes, recently developed in the authors' laboratory, was used to examine the stratification of microbial processes and the change of oxidation-reduction potential (ORP) within an aerobic, sulfate-reducing biofilm. The microelectrodes have tip diameters of 3 to 20 microm and a high spatial resolution. They were used to measure the profiles of oxygen, total dissolved sulfide, ORP, and pH as a function of depth in the biofilm. The biofilm reactor was used to treat an azo-dye-containing wastewater with a chemical oxygen demand of 160 mg/L. The reactor bulk-phase dissolved oxygen concentration of the biofilm was 1.7 mg/L. The experimental results demonstrated that the microbial processes in the biofilm were stratified. In this biofilm, aerobic oxidation took place only in a shallow layer of 0.55 mm near the surface and sulfate reduction occurred in the deeper anoxic zone. The ORP changed with the shift of primary microbial process. The ORP was +362 mV at the biofilm surface and -166 mV near the substratum. Near the interface between the aerobic zone and the sulfate reduction zone, a surprisingly sharp decrease of ORP from a positive potential of +194 mV to a negative potential of -77 mV was observed. This occurred within a narrow band of 50 microm in depth. These new experimental findings support the concept of stratification of microbial processes and the associated ORP change in biofilms.

A mutational epitope for cytochrome C binding to the apoptosis protease activation factor-1

Cytochrome c (Cc) binding to apoptosis protease activation factor-1 (Apaf-1) is a critical activation step in the execution phase of apoptosis. Here we report studies that help define the Cc:Apaf-1 binding surface. It is shown that a large number of Cc residues, including residues 7, 25, 39, 62-65, and 72, are involved in the Cc:Apaf-1 interaction. Mutation of residue 72 eliminated Cc activity whereas mutations of residues 7, 25, 39, and 62-65 showed reduced activity in an additive fashion. The implications of this binding model for both recognition and modulation of protein-protein interactions are briefly discussed.

Sneddon's syndrome: a case report

We report a case of Sneddon's syndrome with the triad of livedo reticularis, hypertension, and neurologic symptoms. The procedures for diagnosis and the tests to delineate clotting abnormalities are examined.

[Lymphocyte subpopulation, interleukin-2 and high affinity interleukin-2 receptor expression in primary nephrotic syndrome]

OBJECTIVE

To understand the cellular immune response during relapse and remission stage in primary nephrotic syndrome (PNS).

METHODS

We applied the radioligand binding assay (RBA), the bioactivity measurement of IL-2, and monoclonal antibody sensitized red blood cell method to evaluate the expression of IL-2R, the production of IL-2 and T lymphocyte subsets of PBMC from 22 patients suffering from PNS, 17 patients with PNS in remission, and 25 normal subjects matched age and sex.

RESULTS

CD3, CD4, CD8, IL-2, IL-2R in relapse were significantly lower than those in control (P < 0.05); all above except CD8 in remission patients were significantly higher than those in relapse, but lower than those in control (P < 0.05).

CONCLUSION

This study suggested that the cell mediated immunity (CMI) during acute nephrotic phase decreased; the deficiency of CMI of PNS in remission improved a lot when compared with the acute phase, but still not recovered completely; the deficiency of CMI with PNS in remission might be one of the causes of easily recurring of PNS.

Angiogenesis inhibitor TNP-470 reduces human pancreatic cancer growth

In this study we investigated the effects of the angiogenesis inhibitor TNP-470 on human pancreatic cancer cells in vitro and in vivo. The action of TNP-470 on vascular endothelial growth factor (VEGF) was also assessed. In vitro human pancreatic cancer cells (MIAPaCa-2, AsPC-1, and Capan-1), and human umbilical vein endothelial cells (HUVEC) were exposed to increasing concentrations (1 pg/ml to 100 microg/ml) of TNP-470. Cell proliferation was assessed after 3 days by cell count and MTT assay. In vivo, 5 x 10(6) pancreatic cancer cells were injected subcutaneously into nude mice. Four weeks later, 1 mm3 fragments of the resulting tumors were implanted into the pancreas of other mice. Animals received either TNP-470 (30 mg/kg every other day) or vehicle subcutaneously for 14 weeks. The volume of the primary tumor and metastatic spread were determined at autopsy. Concentrations of VEGF were determined in serum (VEGF(S)) and ascites (VEGF(A)) by enzyme-linked immunosorbent assay. Microvessel density was analyzed by immunohistochemistry in CD31-stained tumor sections. In vitro, proliferation and viability of the human pancreatic cancer cell lines were significantly inhibited at high concentrations of TNP-470 (> 1 microg/ml). In contrast, TNP-470 effectively decreased the growth of HUVEC at 100 pg/ml. In vivo, tumor volume and dissemination scores were significantly lower in all three pancreatic cancer cell lines. VEGF(S) and VEGF(A) were not different between treated groups. Treatment with TNP-470 significantly reduced neoangiogenesis in tumors of all three human pancreatic cancer cell lines: MIAPaCa-2 = 74.8 +/- 7.8/0.74 mm2 vs. 24.8 +/- 3.7/0.74 mm2; AsPC-1 = 65.3 +/- 5.0/0.74 mm2 vs. 26.0 +/- 3.4/0.74 mm2; and Capan-1 = 82.2 +/- 5.8/0.74 mm2 vs. 26.9 +/- 2.5/0.74 mm2 (P < 0.001). However, survival was not statistically different between groups. TNP-470 reduced tumor growth and metastatic spread of pancreatic cancer in vivo. This was probably due to the antiproliferative effect of the agent on endothelial cells rather than to the direct inhibition of pancreatic cancer cell growth. TNP-470 activity was not associated with alteration of VEGF secretion.

Biofilm structure and mass transfer in a gas phase trickle-bed biofilter

Mass transport phenomena occurring in the biofilms of gas phase trickle-bed biofilters are investigated in this study. The effect of biofilm structure on mass transfer mechanisms is examined using experimental observation from the operating of biofilters, microelectrode techniques and microscopic examination. Since the biofilms of biofilters used for waste gas treatment are not completely saturated with water, there is not a distinguishable liquid layer outside the biofilm. Results suggest that due to this characteristic, gas phase substrates (such as oxygen or volatile organic compounds) may not be limited by the aqueous phase because transport of the compound into the biofilm can occur directly through non-wetted areas. On the other hand, for substrates that are present only in the liquid phase, such as nitrate, the mass transfer limitation is more serious because of the limited liquid supply. Microscopic observations show that a layered structure with void spaces exists within the biofilm. Oxygen concentration distributions along the depth of the biofilms are examined using an oxygen microelectrode. Results indicate that there are some high dissolved oxygen zones inside the biofilm, which suggests the existence of passages for oxygen transfer into the deeper sections of the biofilm in a gas phase trickle-bed biofilter. Both the low gas-liquid mass transfer resistance and the resulting internal structure contribute to the high oxygen penetration within the biofilms in gas phase trickle-bed biofilters.

Teaching future professors how to teach

This paper describes a course designed to provide hands-on teaching experience to future professors and to incorporate techniques for more effective teaching. A team of Ph.D. candidates, under the direction of a senior faculty member, prepared a new course from beginning to end and then offered it to a class of graduate students. The course was developed using the unit map concept so that the presentations by the five student-instructors complemented and built upon one another. Immediately after each class, feedback was given to the student-instructors by the faculty advisor and the other student-instructors. Review of video tapes of the lecture reinforced this feedback. At the completion of the course, both students and student-instructors were surveyed as to the effectiveness of the course and the student-instructors. This teaching experience and the feedback obtained from the surveys will be invaluable to the student-instructors in their future development.