Studies on a kinetic model for butyric acid bioproduction by Clostridium butyricum

AIMS

This paper discusses the establishment of a kinetic model for cell growth, butyric acid production and substrate consumption of Clostridium butyricum ZJUCB in batch cultivation.

METHODS AND RESULTS

Mathematic simulations were proposed by the logistic equation for the cell growth, the Luedeking-Piret equation for butyric acid production and the Luedeking-Piret-like equation for glucose consumption.

CONCLUSION

We compared the performance of our model against that obtained by the empirically experimental design. The experiment-validated model was found suitable for studying butyric acid fermentation kinetics in a complex dynamic behaviour of C. butyricum, especially for its singular growth phenomenon.

SIGNIFICANCE AND IMPACT OF THE STUDY

The model parameters are estimated from the data fitting and evaluated for simulation of the time courses of the concentrations of cell biomass, butyric acid and glucose and the model appears to fit the experimental data well. The results may be useful for butyric acid production by microbial fermentation.

7beta-hydroxycholesterol reduces the extent of reactive gliosis caused by iron deposition in the hippocampus but does not attenuate the iron-induced seizures in rats

7beta-Hydroxycholesterol has been previously demonstrated to inhibit astrocytosis in injured cortex or spinal cord of rats. In this study, we explored the inhibitory effects of the liposome containing 7beta-hydroxycholesterol on the reactive astrocytosis caused by the injection of iron into the hippocampus of rats and furthermore evaluated the involvement of reactive astrocytosis in iron-induced epilepsy. Injection of ferric chloride solution unilaterally into the hippocampus of rats induced spontaneous spiking activity ipsilaterally then developed into bilateral hippocampi and generalized convulsive seizures within the first week post-operation, and spontaneous epileptiform activity and generalized seizures lasted as long as 2 weeks post-operation, whereas none of the rats injected with sodium chloride solution unilaterally into the hippocampus developed generalized seizures. With immunohistochemistry and Western blot analyses, apparent reactive astrocytosis in bilateral hippocampi was detected using antibody against glial fibrillary acidic protein 14 days after the injection of ferric chloride solution, but no significant differences were found in the amount of synaptophysin protein, a presynaptic vesicle protein, as compared with the rats injected with sodium chloride solution. Infusion of liposome suspension containing 7beta-hydroxycholesterol into the same site immediately after the injection of ferric chloride solution reduced the extent of the reactive astrocytosis by 50%-55% of the amount of glial fibrillary acidic protein in the hippocampi of both hemispheres, and non-significantly elevated the amount of synaptophysin protein in both sides of hippocampus. However, these effects did not significantly modify the seizure latency and the incidence of generalized seizures in the rats. These findings demonstrate the effects of 7beta-hydroxycholesterol on the inhibition of reactive astrocytosis caused by iron deposition in the hippocampus of rats, and suggest that the reactive astrocytosis may not play a causal role in the development of iron-induced seizures.

Molecular determinants of P2Y2 nucleotide receptor function: implications for proliferative and inflammatory pathways in astrocytes

In the mammalian nervous system, P2 nucleotide receptors mediate neurotransmission, release of proinflammatory cytokines, and reactive astrogliosis. Extracellular nucleotides activate multiple P2 receptors in neurons and glial cells, including G protein-coupled P2Y receptors and P2X receptors, which are ligand-gated ion channels. In glial cells, the P2Y2 receptor subtype, distinguished by its ability to be equipotently activated by ATP and UTP, is coupled to pro-inflammatory signaling pathways. In situ hybridization studies with rodent brain slices indicate that P2Y2 receptors are expressed primarily in the hippocampus and cerebellum. Astrocytes express several P2 receptor subtypes, including P2Y2 receptors whose activation stimulates cell proliferation and migration. P2Y2 receptors, via an RGD (Arg-Gly-Asp) motif in their first extracellular loop, bind to alphavbeta3/beta5 integrins, whereupon P2Y2 receptor activation stimulates integrin signaling pathways that regulate cytoskeletal reorganization and cell motility. The C-terminus of the P2Y2 receptor contains two Src-homology-3 (SH3)-binding domains that upon receptor activation, promote association with Src and transactivation of growth factor receptors. Together, our results indicate that P2Y2 receptors complex with both integrins and growth factor receptors to activate multiple signaling pathways. Thus, P2Y2 receptors present novel targets to control reactive astrogliosis in neurodegenerative diseases.

Recombination of photodissociated iodine: A time-resolved x-ray-diffraction study

A time-resolved x-ray-diffraction experiment is presented that aims to study the recombination of laser-dissociated iodine molecules dissolved in CCl4. This process is monitored over an extended time interval from pico- to microseconds. The variations of atom-atom distances are probed with a milliangstrom resolution. A recent theory of time-resolved x-ray diffraction is used to analyze the experimental data; it employs the correlation function approach of statistical mechanics. The most striking outcome of this study is the experimental determination of time-dependent I-I atom-atom distribution functions. The structure of the CCl4 solvent changes simultaneously; the solvent thus appears as a reaction partner rather than an inert medium hosting it. Thermal expansion of the system is nonuniform in time, an effect due to the presence of the acoustic horizon. One concludes that a time-resolved x-ray diffraction permits real-time visualization of solvent and solute motions during a chemical reaction.

Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital of the Chinese People's Liberation Army

A worldwide outbreak of severe acute respiratory syndrome (SARS) had been reported. Over 8439 SARS cases and 812 SARS-related deaths were reported to the World Health Organization from 32 countries around the world up to 5 July 2003. The mechanism of transmission of SARS-CoV has been limited only to close contacts with patients. Attention was focused on possible transmission by the sewage system because laboratory studies showed that patients excreted coronavirus RNA in their stools in Amoy Gardens in Hong Kong. To explore whether the stool of SARS patients or the sewage containing the stool of patients would transmit SARS-CoV or not, we used a style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing, as well as cell culture, semi-nested RT-PCR and sequencing of genes to detect and identify the viruses from sewage. There was no live SARS-CoV detected in the sewage in these assays. The nucleic acid of SARS-CoV was found in the sewage before disinfection from both hospitals by PCR. After disinfection, SARS-CoV RNA could be detected from some samples from the 309th Hospital of the Chinese People's Liberation Army, but not from Xiao Tang Shan Hospital after disinfection. In this study, we found that the virus can survive for 14 days in sewage at 4 degrees C, 2 days at 20 degrees C, and its RNA can be detected for 8 days though the virus had been inactivated. In conclusion, this study demonstrates that the RNA of SARS-CoV could be detected from the concentrates of sewage of both hospitals receiving SARS patients before disinfection and occasionally after disinfection though there was no live SARS-CoV; thus much attention should be paid to the treatment of stools of patients and the sewage of hospitals receiving SARS patients.

Response surface methodology for optimizing the fermentation medium of Clostridium butyricum

AIMS

Strains of Clostridium butyricum have been increasingly used as probiotics for both animals and humans. The aim of this study was to develop a growth medium for cultivating C. butyricum ZJUCB using a statistical methodology.

METHODS AND RESULTS

Response surface methodology (RSM) was used to evaluate the effects of variables, namely the concentrations of the glucose, pectin, soyabean cake extract, casein, corn steep flour, ammonium sulphate, sodium bicarbonate and the medium initial pH. A fractional factorial design was applied to study the main factors that affected the growth of a probiotic strain of C. butyricum currently preserved in our lab and the central composite experimental design was adopted to derive a statistical model for optimizing the composition of the fermentation medium. The experimental results showed that the optimum fermentation medium for the growth of C. butyricum was composed of 2% glucose (w/v), 0.5% pectin (w/v), 0.2% casein (w/v), 3.98% soyabean cake extract, 0.1% (NH4)2SO4 (w/v), 0.124% NaHCO3 (w/v), 0.37% corn steep flour (w/v), 0.02% MnSO4 H2O (w/v), 0.02% MgSO4 7H2O (w/v) and 0.002% CaCl2 (w/v) at pH 7.5.

CONCLUSIONS

After incubating 24 h in the optimum fermentation medium, the populations of the viable organisms were estimated to be 10(9) CFU ml(-1). In the present study, we report the optimization of a growth medium that produced increased yields using statistical approach.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of bacteria as a probiotic is showing increasing potential. The development of a growth medium that has a high yield is an obvious need, and the approach to optimizing a growth medium is innovative.

Electron bunch trapping and compression by an intense focused pulse laser

A focused short-pulse laser of TEM (1,0)+TEM (0,1) mode has two intensity peaks in the radial direction, so that the transverse ponderomotive force may trap electrons between the two peaks. At the same time the longitudinal ponderomotive force may accelerate electrons at the head of the laser pulse, when the laser is focused. When the electrons move to the laser tail, the laser may diverge and the electron deceleration becomes relatively weak. Our numerical analyses demonstrate that electrons are trapped well by the laser potential well, and that at the same time the acceleration by the longitudinal ponderomotive force induces the electron bunch compression. This trapping and compression mechanism is unique: the electron bunch can be compressed to the scale of the laser pulse length.

The centrosome-centered cell-brain in apoptosis

Apoptosis (or programmed cell death) is one of the central cellular processes in development, stress response, aging, carcinogenesis, and disease in multi-cellular eukaryotes. Although great effort has been made, the detailed mechanism through which apoptosis is initiated is yet unclear. Previously, the centrosome, or more explicitly the complex comprising the centrosome, centrioles, and connecting filaments, was reported to be required for apoptosis. It may be through this 'cell brain', reminiscent of the long known brain of animals (or humans), that complicated cellular processes, including apoptosis, are precisely coordinated. In this paper, the latest data to support this contention are scrutinized.

Cell brain abnormalities in cancer development

Cancer has long been regarded as a genetic disease. Therefore, current theories on cancer development focus on genetic alterations affecting oncogenes or tumor suppressor genes. However, the mechanisms through which genetic alterations are induced are largely unknown. In this paper a theory will be developed which interprets cancer as a cell brain illness rather than a genetic disease. The complex comprising the centrosome, normally two centrioles and connecting filaments, was recently termed the 'cell brain', and was found to determine a cell's fate. It is through the cell brain, instead of the genes, that genetic stability and expression are maintained and regulated. Accordingly, the nucleus is regarded as a safe storage for inheriting materials (genes) that primarily act as manufacturing templates. Therefore, cancer should be regarded as a 'brain illness' of a cell, instead of a genetic disease, which is strongly supported by the latest evidence, as discussed in this paper. Such a theory serves to better clarify the confusing observations in cancer development accumulated over the last decades.

Cell brain: a new focus in the postgenomic era

The centrosome, together with the embedded centrioles and connecting filaments, has come to be regarded as the 'brain' of a cell, analogous to the long known brain of an animal or a human being. It is through the 'brain' that different cellular activities are coordinated as a whole. In this article, comparative studies of the principles of life at varying levels and of the new roles of different cellular organelles in maintaining a healthy life for an organism provide further support to this theory, which is discussed based on the latest findings. Hopefully, this new theory can make a great contribution to break the paradigm of nucleus (or genes) as causes of all problems.

Subluminous phase velocity of a focused laser beam and vacuum laser acceleration

It has been found that for a focused laser beam propagating in free space, there exists, surrounding the laser beam axis, a subluminous wave phase velocity region. Relativistic electrons injected into this region can be trapped in the acceleration phase and remain in phase with the laser field for sufficiently long times, thereby receiving considerable energy from the field. Optics placed near the laser focus are not necessary, thus allowing high intensities and large energy gains. Important features of this process are examined via test particle simulations. The resulting energy gains are in agreement with theoretical estimates based on acceleration by the axial laser field.

Cell brain crystallization for cancer therapy

Cancer remains one of the leading causes of death throughout the world. One of the important reasons why conventional treatments fail is the development of resistance to therapeutics. The dual effect concept and self-defense mechanism plus the threshold theory might in part explain the development of resistance, however, the primary cause is unclear. A novel theory, 'cell brain', where, selective crystallization of the 'brain' of a cell (comprising centrosome, centrioles and the connecting filaments) occurs, may be a potential alternate approach to cancer therapy.

Purine signaling and potential new therapeutic approach: possible outcomes of NTPDase inhibition

Interest for extracellular nucleotides has increased since the pioneer work of Burnstock in the early seventies. Research on cellular functions modulated by purines and pyrimidines has led to the identification and characterization of the different components of purine signaling, namely purinoceptors and ecto-nucleotidases. Receptors for tri- and diphosphonucleosides, known as P2 nucleotide receptors, are designated either P2Y receptors, for those coupled to G-proteins, or P2X for those which are ligand gated-ion channels. Ecto-nucleoside triphosphate diphosphohydrolase (NTPDase; EC 3.6.1.5), previously identified as ecto-ATPase, ecto-ATPDase or CD39, is now considered as the main ecto-nucleotidase responsible for the sequential hydrolysis of beta and gamma phosphates of tri- and diphosphonucleosides. More recently, research has been focused on the development of specific agonists and antagonists to P2 purinoceptors. The need to develop specific inhibitors for NTPDase to understand the role of this enzyme has clearly emerged. This paper covers the development of specific molecules targeting purinergic signaling, more specifically the inhibition of NTPDase and their impact on the different physiological systems.

Urinary calcium as a biomarker of renal dysfunction in a general population exposed to cadmium

Urinary beta 2-microglobulin and N-acetyl-beta-D-glucosaminidase have been recommended as sensitive indicators of renal dysfunction induced by cadmium. However, an increase in urinary calcium in early renal damage induced by cadmium has been reported both in humans and in animal experiments. To investigate the feasibility of using urinary calcium as a biomarker of renal dysfunction induced by cadmium, two areas were selected in this study, namely, a polluted area with a 3.71 mg/kg cadmium concentration in rice and a control area with a 0.07 mg/kg cadmium concentration. The total number of participants was 499, made up of 252 in the control group and 247 from the cadmium-polluted area. Urinary cadmium, urinary calcium, and zinc concentrations were measured by atomic absorption spectrometry, and beta 2-microglobulin and N-acetyl-beta-D-glucosaminidase in urine were analyzed. The levels of urinary cadmium and urinary calcium in persons from the exposed area were significantly higher (P < 0.05) than those in the control area for both men and women, but there was no significant difference regarding urinary zinc between the two areas. A significant dose-response relationship between the prevalence of hypercalciuria and the excretion of urinary cadmium was observed, and a significantly increased prevalence of calciuria was found when excretion of urinary cadmium exceeded 2 micrograms/g creatinine. The findings were similar to those for excess urinary secretion of beta 2-microglobulin and N-acetyl-beta-D-glucosaminidase. Because cadmium can affect Ca2+ uptake by tubular cells, with decreased renal Ca2+ reabsorption, calciuria may reflect tubular cell damage caused by cadmium. It was concluded that cadmium exposure can result in increased excretion of urinary calcium in a general population and that there is a significant dose-response relationship. Urinary calcium can therefore be used as a biomarker of renal dysfunction induced by cadmium.

Oral immunization with hepatitis B surface antigen expressed in transgenic plants

Oral immunogenicity of recombinant hepatitis B surface antigen (HBsAg) derived from yeast (purified product) or in transgenic potatoes (uncooked unprocessed sample) was compared. An oral adjuvant, cholera toxin, was used to increase immune responses. Transgenic plant material containing HBsAg was the superior means of both inducing a primary immune response and priming the mice to respond to a subsequent parenteral injection of HBsAg. Electron microscopy of transgenic plant samples revealed evidence that the HBsAg accumulated intracellularly; we conclude that natural bioencapsulation of the antigen may provide protection from degradation in the digestive tract until plant cell degradation occurs near an immune effector site in the gut. The correlate of protection from hepatitis B virus infection is serum antibody titers induced by vaccination; the protective level in humans is 10 milliunits/ml or greater. Mice fed HBsAg-transgenic potatoes produced HBsAg-specific serum antibodies that exceeded the protective level and, on parenteral boosting, generated a strong long-lasting secondary antibody response. We have also shown the effectiveness of oral delivery by using a parenteral prime-oral boost immunization schedule. The demonstrated success of oral immunization for hepatitis B virus with an "edible vaccine" provides a strategy for contributing a means to achieve global immunization for hepatitis B prevention and eradication.

[Diagnosis and management of endoleak after endovascular repair of abdominal aortic aneurysm]

OBJECTIVE

To determine the diagnosis and management of endoleak after endovascular repair of abdominal aortic aneurysm (AAA).

METHODS

We analysed retrospectively the data of 37 cases of infrarenal AAA treated by endovascular repair and investigated the reasons, managements, results and prognosis of endoleaks.

RESULTS

Of 13 patients with endoleak at stent-graft deployment, 6 developed type I endoleak, 3 type II endoleak, 2 type III endoleak, 1 type IV endoleak, and 1 unknown reason. Type I and III endoleaks disappeared after management with additional techniques. The primary endoleak rate was 13.5%(5/37). Three sealed endoleak, 2 persistent endoleaks and 2 secondary endoleaks were found during follow up. The late endoleak rate was 10.8% (4/37).

CONCLUSIONS

Endoleak is a chief complication after endovascular repair of infrarenal AAA. The influencing factors for endoleak include neck morphology, distance, angulation, calcification, stent-graft selection and side branching arteries. Additional procedure and follow up are very important. Techniques to find endoleak include CTA, Duplex and MRA after operation. Endoleak with enlarged aneurysm should be treated actively.

DNA breaks in hypermutating immunoglobulin genes: evidence for a break-and-repair pathway of somatic hypermutation

To test the hypothesis that immunoglobulin gene hypermutation in vivo employs a pathway in which DNA breaks are introduced and subsequently repaired to produce mutations, we have used a PCR-based assay to detect and identify single-strand DNA breaks in lambda1 genes of actively hypermutating primary murine germinal center B cells. We find that there is a two- to threefold excess of breaks in lambda1 genes of hypermutating B cells, relative to nonhypermutating B cells, and that 1.3% of germinal center B cells contain breaks in the lambda1 gene that are associated with hypermutation. Breaks were found in both top and bottom DNA strands and were localized to the region of lambda1 that actively hypermutates, but duplex breaks accounted for only a subset of breaks identified. Almost half of the breaks in hypermutating B cells occurred at hotspots, sites at which two or more independent breaks were identified. Breaksite hotspots were associated with characteristic sequence motifs: a pyrimidine-rich motif, either RCTYT or CCYC; and RGYW, a sequence motif associated with hypermutation hotspots. The sequence motifs identified at breaksite hotspots should inform the design of substrates for characterization of activities that participate in the hypermutation pathway.

An RGD sequence in the P2Y(2) receptor interacts with alpha(V)beta(3) integrins and is required for G(o)-mediated signal transduction

The P2Y(2) nucleotide receptor (P2Y(2)R) contains the integrin-binding domain arginine-glycine-aspartic acid (RGD) in its first extracellular loop, raising the possibility that this G protein-coupled receptor interacts directly with an integrin. Binding of a peptide corresponding to the first extracellular loop of the P2Y(2)R to K562 erythroleukemia cells was inhibited by antibodies against alpha(V)beta(3)/beta(5) integrins and the integrin-associated thrombospondin receptor, CD47. Immunofluorescence of cells transfected with epitope-tagged P2Y(2)Rs indicated that alpha(V) integrins colocalized 10-fold better with the wild-type P2Y(2)R than with a mutant P2Y(2)R in which the RGD sequence was replaced with RGE. Compared with the wild-type P2Y(2)R, the RGE mutant required 1,000-fold higher agonist concentrations to phosphorylate focal adhesion kinase, activate extracellular signal-regulated kinases, and initiate the PLC-dependent mobilization of intracellular Ca(2+). Furthermore, an anti-alpha(V) integrin antibody partially inhibited these signaling events mediated by the wild-type P2Y(2)R. Pertussis toxin, an inhibitor of G(i/o) proteins, partially inhibited Ca(2+) mobilization mediated by the wild-type P2Y(2)R, but not by the RGE mutant, suggesting that the RGD sequence is required for P2Y(2)R-mediated activation of G(o), but not G(q). Since CD47 has been shown to associate directly with G(i/o) family proteins, these results suggest that interactions between P2Y(2)Rs, integrins, and CD47 may be important for coupling the P2Y(2)R to G(o).

Breaksite batch mapping, a rapid method for assay and identification of DNA breaksites in mammalian cells

DNA breaks occur during many processes in mammalian cells, including recombination, repair, mutagenesis and apoptosis. Here we report a simple and rapid method for assaying DNA breaks and identifying DNA breaksites. Breaksites are first tagged and amplified by ligation-mediated PCR (LM-PCR), using nested PCR primers to increase the specificity and sensitivity of amplification. Breaksites are then mapped by batch sequencing LM-PCR products. This allows easy identification of multiple breaksites per reaction without tedious fractionation of PCR products by gel electrophoresis or cloning. Breaksite batch mapping requires little starting material and can be used to identify either single- or double-strand breaks.

[The study on relation of human papillomavirus and P53 expression with bladder transitional cell carcinoma]

OBJECTIVE

To study the relationship between the bladder transitional cell carcinoma and the human papillomavirus (HPV) types 6, 11, 16, 18 and P53.

METHODS

We used polymerase chain reaction (PCR) to test HPV type 6, 11, 16 and 18 infection from 75 cases of bladder cancer, and used immunohistochemistry method to detect P53 expression.

RESULTS

The positive rates of HPV types 6, 11, 16 and 18 were 6.7%, 5.3%, 33.3% and 6.7%, respectively. The positive rate of low risk HPV type (6/11) was 9.3% (7/75), and that of high risk HPV types (16/18) was 34.7% (26/75). There were 8 cases with two or three HPV types mixed infection, accounting for 10.6%, HPV types 6,11,16,18 in tumor metastasis group were significantly higher than that in non-metastasis group. The positive rates of HPV 16, 18 types in G3 were significantly higher than that in G1 and G2. HPV type 16 was the main type in bladder cancer. Positive rate of P53 expression was 44%.

CONCLUSIONS

These results implicated that the occurrence and development of bladder transitional cell carcinoma may be closely related to the high risk HPV type infection and P53 expression.

[Distribution of interleukin-6 receptors (CD(126) and CD(w130)) on circulating lymphocytes in patients with lupus nephritis]

OBJECTIVE

To study the distribution of IL-6 receptors (CD(126) and CD(w130)) on lymphocytes in patients with lupus nephritis (LN).

METHOD

The percentages of lymphocyte subsets were examined by direct two colour immunofluorescence on flow cytometry.

RESULTS

(1) In active and inactive cases, the percentages of CD(+)(4) cells obviously decreased as compared with the normal controls (P < 0.01). Increased numbers of CD(+)(8) cells could be detected in LN patients (P < 0.05), especially in active cases (P < 0.01). Lymphocytes of active cases contained significantly greater percentage of CD(+)(23) cells than those of normal subjects (P < 0.05). On the contrary, the percentage of CD(+)(23) cells was statistically lower in the inactive cases than in normal subjects (P < 0.01). No significant difference in the percentages of CD(+)(126) and CD(+)(w130) cells was observed among the active, inactive and healthy groups (P > 0.05); (2) The proportion of CD(+)(4) CD(+)(126) and CD(+)(4) CD(+)(w130) cells in total lymphocytes was significantly lower in the active than in the inactive ones or normal subjects (P < 0.05; P < 0.01), whereas that of CD(+)(8) CD(+)(126) and CD(+)(8) CD(+)(w130) cells was not different among the active, inactive and normal subjects (P > 0.05). The proportion of CD(+)(23) CD(+)(126) cells and CD(+)(23) CD(+)(w130) cells augmented significantly in the active (P < 0.05), whereas it lessened in the inactive without statistical meaning as compared with the normal subjects (P > 0.05). (3) There was a positive correlation between the percentage of CD(+)(23) CD(+)(126) cells and that of CD(+)(23) CD(+)(w130) cells in total lymphocytes in the active group (r = 0.756, P < 0.05). However, no correlation between the percentage of CD(+)(23) CD(+)(126) cells and that of CD(+)(23) CD(+)(w130) cells in total lymphocytes was found in the inactive (r = 0.376, P > 0.05) or normal group (r = 0.256, P > 0.05); (4) The fraction of CD(+)(23) cells expressing CD(126) and CD(w130) was related to the SLE disease activity index (SLEDAI) and lymphopenia (P < 0.05, P < 0.005). But it was neither associated with the number of damaged organs and the degree of damage, not with that of ANA, anti-dsDNA antibody and complements (C(3) and C(4)) (P > 0.05).

CONCLUSIONS

LN patients present not only B cell hyperactivity but also T cell abnormality. In active cases, there is abnormal distribution of IL-6 receptors on lymphocytes: reduced CD(126) and CD(w130) expression on CD(+)(4) cells and elevated CD(126) and CD(w130) expression on CD(+)(23) cells. Detecting the proportion of CD(+)(23) CD(+)(126) cells or CD(+)(23) CD(+)(w130) cells in total lymphocytes may serve as one of activity indexes for LN patients.

A threshold concept for cancer therapy

Oxygen free radicals have been implicated in many disease processes, including aging and carcinogenesis, and have been associated with a variety of complications resulting from the treatment of cancer. As a result, the treatment of free radical-induced disease with antioxidants or free radical scavengers has become an important therapeutic modality. Ironically, these same oxygen free radicals also play a critical role in anti-cancer therapies. The use of antioxidants such as superoxide dismutase (SOD), in this setting, has been found to decrease the efficacy of anti-tumor therapies, which depend on free radical generation for their action. In addition, increased antioxidant activity can often be utilized by the tumor cell to favor increased growth. Therefore, the appropriate application of oxygen free radicals and antioxidants seems to be critically important in designing proper strategies for both prevention and treatment of malignant disorders. This review will summarize free radical and antioxidant regimens that have been employed to date, examine some of the problems associated with these regimens, introduce the 'threshold concept' explaining the dual effects of oxygen free radicals and antioxidants, and discuss a novel hypothesis regarding therapy that could potentially improve outcome in cancer patients.

[Abdominal aortic aneurysm treated by endovascular stent-graft and conventional surgical repair: a comparison]

OBJECTIVE

To evaluate the feasibility of abdominal aortic aneurysm (AAA) treated by endovascular stent-graft.

METHODS

The clinical data of 52 patients with AAA treated by endovascular stent-graft (n = 20) and conventional surgical repair (n = 32) were analysed retrospectively. Patients conditions, operative hours, blood loss, function recovery and complications were compared.

RESULTS

No significant difference was observed in sex, age, other disease, anesthesia risk category, aneurysm type, aneurysm diameter, technical success rate, and mortality rate between the groups (P > 0.05). The patients who underwent intraluminal treatment had significant reductions in operative time, blood loss, intensive care unit and hospitalization. But there was a high complication rate in the endovascular stent-graft group. All complications were connected with the interventional technique; endo-leak was the chief complication after operation.

CONCLUSIONS

Endovascular treatment has marked merits such as reduced trauma, short hospitalization stays, and early functional recovery. It is suitable for the patients who can't undergo open surgical repair. But the complications caused by this technique needs further study.

[Endoluminal stent-graft repair of aortic aneurysms]

OBJECTIVE

To study the clinical value of the treatment of aortic aneurysms with endovascular stent-graft prosthesis.

METHODS

After a unilateral surgical arteriotomy, Talent, Vanguard and Chinese stent-graft were advanced through the femoral arteries and placed in the proper position of the aneurysm sac under X-ray fluoroscopic guidance.

RESULTS

Four patients with descending aneurysm, 1 patient with abdominal aortic aneurysm (AAA) involving the renal artery, superior mesenteric artery and celiac artery, and 1 patient with right common iliac artery aneurysm received straight stent-grafts. Five patients with infrarenal AAA received bifurcated stent-grafts. CT and MRA were performed during a follow-up of 3 - 19 months. Aortic aneurysms were completely excluded from the circulation. Five patients prolonged fever was noted and 1 patient was found to have a leakage 3 months later, and hemiplegia in 1 after procedure.

CONCLUSIONS

Endovascular treatment of aortic aneurysm is technically feasible and can effectively exclude aortic aneurysms from the circulation. Endoluminal repair may serve as an interventional strategy to treat aneurysm, especially in patients at high surgical risk, but long term effect needs further study.

Conditions for electron capture by an ultraintense stationary laser beam

We present in this paper a quantitative study of an effect, in which a low-energy free electron is captured and violently accelerated to GeV final kinetic energy by a stationary extra-high-intensity laser beam (Q0 identical witheE/m(e)omegac greater, similar100). The conditions under which this phenomenon can occur, such as the momentum range, incident angle of the incoming electron, the waist width of the laser beam, etc., have been investigated in detail.

High-intensity laser-induced electron acceleration in vacuum

In this paper, an approximate pulsed-laser-beam solution of Maxwell's equation in vacuum is derived. Then with the numerical simulation method, electron acceleration induced by high-intensity [Q(0)=eE(0)/(m(e)omega c)=3] lasers is discussed in connection with the recent experiment of Malka et al. It is found that the maximum energy gain and the relationship between the final energy and the scattering angle can be well reproduced, but the polarization effect of electron-laser interactions is not very prominent. These results show that the ponderomotive potential model is still applicable, which means that the stimulated Compton scattering is the main fundamental mechanism responsible for the electron acceleration at this laser intensity.

Current perspectives in immunotherapy

Since the declaration of the war on cancer in 1971, our ability to effectively treat cancer has been less successful than anticipated. Surgery and radiation therapy remain our most effective treatment modalities, with chemotherapy proving beneficial in only a limited number of tumor types. The reality of this poor response to conventional therapy has prompted a search for other potentially beneficial therapies. The idea of using the immune system to eradicate tumor is not new. Over 100 years ago, William Coley (in 1893) first reported on the ability to induce tumor regressions by nonspecific activation of the immune system in response to bacterial toxins. Despite this early beginning, efforts to reliably manipulate the immune system to promote tumor regression has been universally disappointing. With recent advances in our understanding of the immune system, and the identification and availability of numerous growth promoting and growth-suppression cytokines, the concept of immunotherapy being a useful therapeutic intervention for the treatment of cancer is becoming a reality. Immunology in general, and tumor immunology specifically, are fields foreign to the practicing tumor surgeon. As progress in these fields are made, it will become important for the surgical oncologist to have a better understanding of tumor immunology as it relates to therapy. This paper reviews our current understanding of the immune system as it relates to cancer immunotherapy (using primary intracranial glioma as the tumor model), and then relates this knowledge to recent work in the development of tumor-specific vaccines.

Urinary N-acetyl-beta-D-glucosaminidase isoenzymes as biomarker of renal dysfunction caused by cadmium in a general population

N-Acetyl-beta-D-glucosaminidase (NAG) and its isoenzymes in urine have been studied in a population group residing in a polluted area in China. The area studied was contaminated by industrial wastewater from a nearby smelter that discharged cadmium-polluted wastewater into a river used for the irrigation of rice fields. Cadmium concentrations in rice were 3.70, 0.51, and 0.07 mg/kg for the highly and moderately polluted areas and the control area, respectively. Cadmium concentrations in urine exceeded 5 microgram/liter in the majority of subjects in the most highly polluted area. There was a marked dose-dependent increase in NAG and NAG B content of urine related both to urinary cadmium and to the calculated cadmium uptake. It is concluded that urinary NAG and its isoenzymes could serve as a sensitive biomarker of renal dysfunction in cadmium-exposed populations. The mechanisms underlying the increase in NAG and its isoenzymes after cadmium exposure need to be studied further.

Color Doppler energy and related quantitative analysis of gestational trophoblastic tumors

OBJECTIVE

To assess the reliability of color Doppler energy (CDE) and a related quantitative analysis for detection and follow-up of uterine involvement in gestational trophoblastic tumor.

METHOD

CDE was performed in 19 patients with trophoblastic tumor, in 25 women in early pregnancy and 25 non-pregnant women. The blood flow area ratio (BFAR) in CDE was used as an index representing uterine involvement. In nine of the 19 patients, BFAR was measured before, during and at termination of chemotherapy.

RESULT

The BFAR (mean +/- S.D.) of uterine profiles in 19 patients (39.9 +/- 1.3%) was significantly higher than that in 25 pregnant women (24.6 +/- 10.1%, P = 0.002) and in 25 non-pregnant women (14.8 +/- 5.7%, P = 0.001). In the follow-up of nine patients, when beta-hCG was less than 3.1 ng/ml during the treatment, the BFAR (38.7 +/- 11.9%) decreased below that (44.2 +/- 14.6%) seen prior to treatment (P = 0.009) and was much lower at termination of treatment (27.5 +/- 12.3%, P = 0.048).

CONCLUSION

These data support the use of CDE and the related quantitative analysis as a new method for detecting and follow-up of uterine involvement in patients with trophoblastic tumors.

[Regulation of adherence to serum-coated hydroxyapatite by Streptococcus sanguis]

OBJECTIVE

To investigate the effects of pH and calcium iron on adhesion of Streptococcus sanguis to serum-coated hydroxyapatite.

METHODS

The adhesion model in vitro established by Clark W. B. in 1977 was used to quantify adsorptive cells through [3H] thymidine labelling.

RESULTS

The cpm values between different pH groups showed significant differences. Also, there were significant differences of cpm values between calcium groups and control group.

CONCLUSION

Either pH or calcium iron has obvious effect on adherence of Stroptococcus sanguis to serum-coated hydroxyapatite. The findings suggest that regulating pH and concentration of calcium iron can help to change colonization on teeth surfaces by Streptococcus sanguis in periodontal circumstance.

[The study on cytomegalovirus infection associated with vascular complications in patients with essential hypertension]

OBJECTIVE

This paper studied HCMV infection inpatients with essential hypertension and the relationship of HCMV infection with vascular complications.

METHODS

Indirect ELISA method was used to detect human cytomegalovirus (HCMV) specific antibodies in sera of 105 patients with essential hypertension.

RESULTS

The results showed that the positive rates of active HCMV-IgM and IgA antibodies were 26.67% and 20.95%, respectively, higher than that of the control group (6.67%). The positive rate of HCMV active IgM antibody in III stage group was significantly higher than that of I + II stage groups (P < 0.01). Active HCMV infective rate was higher in patients with vascular complication.

CONCLUSION

These results suggested that HCMV active infection may be associated with vascular complication.

Somatic hypermutation and the three R's: repair, replication and recombination

Somatic hypermutation introduces single base changes into the rearranged variable (V) regions of antigen activated B cells at a rate of approximately 1 mutation per kilobase per generation. This is nearly a million-fold higher than the typical mutation rate in a mammalian somatic cell. Rampant mutation at this level could have a devastating effect, but somatic hypermutation is accurately targeted and tightly regulated. Here, we provide an overview of immunoglobulin gene somatic hypermutation; discuss mechanisms of mutation in model organisms that may be relevant to the hypermutation mechanism; and review recent advances toward understanding the possible role(s) of DNA repair, replication, and recombination in this fascinating process.

PMS2-deficiency diminishes hypermutation of a lambda1 transgene in young but not older mice

The Pms2 gene is involved in DNA mismatch repair in mammalian cells, and has recently been shown to affect hypermutation of mammalian immunoglobulin genes. We have studied hypermutation of a lambda1 transgene in chronically stimulated Peyer's patch B cells of both young and old mice deficient in function of Pms2. In young (3-4 months) mice, somatic hypermutation is fourfold lower in PMS2-deficient mice than in control mice. This difference is statistically significant (P < 0.05). In contrast, in older mice (9 months of age), hypermutation levels are indistinguishable in the Pms2-/- and Pms2+/+ backgrounds. In the older mice, there was no clear difference in the fraction of clones carrying either any mutations or at least two mutations when PMS2-deficient mice were compared with their wild-type littermates. As genomic instability increases with age, this observation is difficult to reconcile with the hypothesis that highly mutated B cells cannot survive in Peyer's patches. Moreover, there were clear differences apparent in the mutation spectra of the Pms2-/- and Pms2+/+ mice. In the PMS2-deficient background, deletion and insertion mutations were found, and there was a significant decrease in the ratio of A mutations to T mutations in comparison with the Pms2+/+ controls. Our data support the hypothesis that PMS2 functions in somatic hypermutation, and are most consistent with the hypothesis that the role of PMS2 is direct rather than indirect.

[Clinical significance and expression of Bcl-2 protein in patients with systemic lupus erythematosus]

OBJECTIVE

To investigate the pathogenesis and clinical evaluation for expression of Bcl-2 in lymphocytes and renal tissues of 31 patients with systemic lupus erythematosus (SLE).

METHODS

Bcl-2 protein levels in T, B cells and renal tissues were examined by two-colour cytofluorography, and immunohistochemical staining (LSAB method) respectively.

RESULTS

Compared with inactive SLE patients and normal controls, a proposition of T cells (including CD(3)(+), CD(4)(+) and CD(8)(+) subgroups) expressing Bcl-2 protein increased significantly in active SLE patients. However, Bcl-2 protein levels are not statistically different in CD(19)(+) B cells among all groups. Mean fluorescence intensity (MFI) levels of Bcl-2 protein on CD(3)(+) T cells was positively related to SLE disease activity index (SLEDAI) among the SLE patients, which wasn't related to ESR, complement (C(3), C(4)) and autoantibody (ANA, anti-dsDNA, anti-Sm) positivity. The population of Bcl-2 positive intraglomerular cells was correlated significantly with the grade of mesangial cell increase and the number of proliferating cell nuclear antigen (PCNA) positive glomerular cells, and 24-hour urinary protein.

CONCLUSION

Overexpression of apoptosis-related Bcl-2 protein might play an important rule in the prolonged proliferation of mesangial cells and glomerular hypercellularity and in the active period of SLE patients, Bcl-2 expression levels of peripheral blood T lymphocytes might serve as an active index for SLE.

Antioxidant inhibitors for cancer therapy

Built-in cellular defense mechanisms play a major role in a tumor's protection against non-surgical antineoplastic therapies. Of these, the overexpression of antioxidants such as superoxide dismutase (SOD) may be the most important. Oxygen radicals are highly toxic, and have been implicated in various diseases, including carcinogenesis and aging. They produce a variety of pathological changes through lipid peroxidation and DNA damage. Therefore, treating free-radical-induced diseases with antioxidants has been an accepted therapeutic approach. Ironically, however, the underlying mechanism that most chemotherapeutic agents and ionizing radiation exert on tumor cell kill is not increased antioxidation but rather the production of more free radicals leading to irreversible tissue injury. A small increase in reactive oxygen species (ROS) following non-surgical antineoplastic therapies induces the expression of antioxidants such as SOD, but overproduction of ROS, conversely, exhausts the production of SOD and other adaptive antioxidant defenses. Based on these considerations, we hypothesize that the appropriate administration of antioxidant inhibitors and/or free-radical-generating compounds may be a useful strategy in the treatment of solid tumors.

Intralesionally implanted cisplatin plus systemic carmustine for the treatment of brain tumor in rats

BACKGROUND AND OBJECTIVES

The benefit of conventional chemotherapy for the treatment of malignant brain tumors, although limited, is real. A major obstacle in the treatment of these lesions is the ability to deliver drug across the blood-brain barrier (BBB). Local drug implantation, circumventing the BBB, has been a useful strategy for treatment of intracranial lesions, and may work synergistically with systemic chemotherapy. To test this hypothesis, either intraperitoneal (i.p.) carmustine or cisplatin was combined with the intracranial (i.c.) administration of polymer-delivered cisplatin in rats with intracranial tumors.

METHODS AND RESULTS

9L gliosarcoma tumor cells (5 x 10(3)) were administered through a right frontal lobe cannula in rats 7 days prior to treatments. Cisplatin-loaded biodegradable polymer was then administered via the cannula, with free cisplatin or carmustine injected i.p. Animals were monitored for 60 days post-treatment. In experiment 1, i.c. cisplatin at a dose of 0.5, 1.0, 2.0, and 4.0 mg/m2 resulted in a mean survival time of 34 +/- 3, 39 +/- 14, 47 +/- 11, and 31 +/- 20 days (MST +/- SD), respectively, compared to 26 +/- 4 days in the control group and 30 +/- 7 days in the group treated with 50 mg/m2 i.p. free cisplatin. In experiment 2, i.p. free cisplatin at 25, 40, 50, and 100 mg/m2 resulted in a MST of 28 +/- 3, 30 +/- 4, 32 +/- 3, and 14 +/- 8 days, respectively, compared to 26 +/- 1 days in the control group. In experiment 3, the MST in the groups treated with 0.5 mg/m2 of i.c. cisplatin, 25 mg/m2 of i.p. cisplatin, 10 mg/kg of i.p. carmustine, i.c. cisplatin (0.5 mg/m2) plus i.p. cisplatin (25 mg/m2), and i.c. cisplatin (0.5 mg/m2) plus i.p. carmustine (10 mg/kg) was 30 +/- 4 days (P > 0.05), 28 +/- 2 (P > 0.05), 36 +/- 4 (P < 0.01), 32 +/- 3 (P < 0.01), and 50 +/- 11 days (P < 0.01), respectively, compared to the tumor control group (26 +/- 1 days). Long-term survivors (29%) were seen only in the i.c. cisplatin plus i.p. carmustine group. Additive toxicity was not observed.

CONCLUSIONS

Intralesional polymer-delivered (i.c.) cisplatin plus systemic (i.p.) carmustine is highly effective for the treatment of intracranial 9L gliosarcoma in tumors.

A lambda 3' enhancer drives active and untemplated somatic hypermutation of a lambda 1 transgene

Somatic hypermutation is a highly regulated process that targets mutations to the rearranged Ig genes. Little is known about the cis-elements required for somatic hypermutation of the lambda light chain gene. We have studied somatic hypermutation of a rearranged lambda 1 transgene under the control of either a lambda 2-4 or kappa 3' enhancer. The mutations in the transgenes were analyzed by sequencing DNA amplified from hypermutating Peyer's patch B cells. The results indicate that the lambda 3' enhancer can drive active hypermutation of a lambda 1 transgene in Peyer's patch cells. The lambda 1 transgene under analysis carried two marked V lambda 2 genes immediately upstream that could serve as sequence donors in possible gene conversion events. There was no evidence of sequence transfer to the hypermutated lambda 1 gene, suggesting that gene conversion is not a major mechanism for somatic hypermutation in mice.

Recombination-based mechanisms for somatic hypermutation

We review some experiments designed to test recombination-based mechanisms for somatic hypermutation in mice, particularly mechanisms involving templated mutation or gene conversion. As recombination and repair functions are highly conserved among prokaryotes and eukaryotes, pathways of mutation in microorganisms may prove relevant to the mechanism of somatic hypermutation. Escherichia coli initiates a recombination-based pathway of mutation in response to environmental stimuli, and this "adaptive" pathway of mutation has striking similarities with somatic hypermutation, as does a process of mutagenic repair that occurs at double-strand breaks in Saccharomyces cerevisiae. We present a model for recombination-based hypermutation of the immunoglobulin loci which could result in either templated or non-templated mutation.

The coat protein of turnip crinkle virus is involved in subviral RNA-mediated symptom modulation and accumulation

Some satellite (sat-) and defective interfering (DI) RNAs associated with plant viruses intensify or ameliorate the symptoms of the virus. We recently demonstrated that the TCV coat protein (CP) is involved in symptom modulation by sat-RNA C. Two additional subviral RNAs have now been tested for effect of the CP on symptom modulation. DI RNA G, which normally intensifies the symptoms of TCV, is able to attenuate symptoms if the TCV CP is replaced with the CP of cardamine chlorotic fleck virus. DI RNA G had no effect on the symptoms of TCV with a single base alteration in the CP open reading frame, unlike sat-RNA C, which was able to ameliorate the symptoms of the mutant TCV. Using a hybrid sat-RNA constructed from sat-RNA C and TCV (which shares a similar 3'-end region with DI RNA G), the 3'-terminal 53 bases of sat-RNA C were found to be involved in symptom attenuation, which was directly correlated with the lack of detectable viral genomic RNA in whole plants. Sat-RNA D had no effect on the symptoms of mutant or wild-type TCV. The accumulation of TCV subviral RNAs in plants and protoplasts was also found to be strongly influenced by the presence or absence of the wild-type TCV CP.

Satellite RNA-mediated resistance to turnip crinkle virus in Arabidopsis involves a reduction in virus movement

Satellite RNAs (sat-RNAs) are parasites of viruses that can mediate resistance to the helper virus. We previously showed that a sat-RNA (sat-RNA C) of turnip crinkle virus (TCV), which normally intensifies symptoms of TCV, is able to attenuate symptoms when TCV contains the coat protein (CP) of cardamine chlorotic fleck virus (TCV-CPCCFV). We have now determined that sat-RNA C also attenuates symptoms of TCV containing an alteration in the initiating AUG of the CP open reading frame (TCV-CPm). TCV-CPm, which is able to move systemically in both the TCV-susceptible ecotype Columbia (Col-0) and the TCV-resistant ecotype Dijon (Di-0), produced a reduced level of CP and no detectable virions in infected plants. Sat-RNA C reduced the accumulation of TCV-CPm by < 25% in protoplasts while reducing the level of TCV-CPm by 90 to 100% in uninoculated leaves of Col-0 and Di-0. Our results suggest that in the presence of a reduced level of a possibly altered CP, sat-RNA C reduces virus long-distance movement in a manner that is independent of the salicylic acid-dependent defense pathway.

[Coronary artery bypass graft with internal mammary artery in 53 cases]

Coronary bypass graft (CABG) with internal mammary artery was used (IMA) in 53 cases. They were treated medically but not effective. More than one time myocardial infarctions occurred 44 cases, and 16 of them had complicated ventricular aneurysm. All of them had moderate hypothermia cardiopulmonary bypass except one, who was only subjected to anastomosis of left IMA to left anterior descending branch without cardiopulmonary bypass. The mean grafts of this group were 4.28 (lift ventricular aneurysmectomy was performed simultaneously in 4 cases). Operative death was occurred in 4 cases. Of the 35 cases which had been followed for 6 months to 1 year, 30 were free of symptoms, 5 got better and had more physical exertion. It is suggested that CABG with IMA is satisfactory.

Biological monitoring of cadmium exposure and renal effects in a population group residing in a polluted area in China

In an area of China, not previously studied in detail concerning cadmium pollution and possible adverse effects on the kidney of exposed populations, concentrations of cadmium in urine as an indicator of renal accumulation of cadmium was studied and related to indicators of renal dysfunction in order to examine if a relationship could be documented. Cadmium concentrations in urine were analysed by graphite furnace atomic absorption spectrometry and urinary beta-2 microglobulin (UBM) and albumin (UALB) were measured as indicators of renal dysfunction, Rice samples and urine samples were obtained from three areas in Zhejiang province, China, representing a highly exposed area, a medium exposed area and a control area, respectively. Cadmium concentrations in rice were 3.70, 0.51 and 0.072 mg/kg for the heavily, medium polluted areas and the control area, respectively. Cadmium concentrations in urine (geometric means) were 10.7, 1.62 and 0.40 micrograms/l in the high, medium and control areas respectively. There was a clear increase in UBM and UALB in the heavily exposed group in comparison to the control group and a slight increase in the medium exposed group. There was a statistically significant dose-response relationship between cadmium in urine and beta 2-microglobulin excretion in urine, which is similar to what has previously been reported in other countries. The findings constitute the first report concerning a dose-response relationship in this population group in Zhejiang province in China.

[The injury of human lung cultured vascular endothelial cells in vitro added to burned skin extracts]

Human lung cultured vascular endothelial cells model was established in vitro. Two kinds of skin extracts (human burned skin extracts, HBSE, and human natural skin extracts, HNSE) were added to cultured endothelial cells. The results showed that HBSE exerted toxic effect on endothelial cells in vitro. There were significantly higher contents of ET-1, NO, TNF-alpha, and abnormal structural changes in EC in the HBSE group.

Intralesionally implanted cisplatin cures primary brain tumor in rats

BACKGROUND AND OBJECTIVES

Chemotherapy has added little to the overall survival of the patients with primary malignant brain tumors, primarily due to its difficulty penetrating the blood-brain barrier. Use of polymers, releasing high doses of chemotherapy locally over time, is a promising new treatment strategy. Three experiments were conducted to test the effect of cisplatin, released from biodegradable polymer, on rats with 1 week established brain tumor.

METHODS

9L gliosarcoma cells and drug-free or cisplatin-loaded polymer were administered through a right frontal lobe cannula in male Fischer 344 rats. Tumor cells were infused on day 0 and polymer on day 7. Animals were monitored for 60 days.

RESULTS

In experiment one, 0.5 mg/m2 of cisplatin loaded in polymer resulted in a mean survival time (MST) of 51 +/- 14 days with 63% (10/16) rats surviving to day 60. MST for the control group was 24 +/- 4 days (p = 2.5 x 10(-9)). Evidence of clinical or histologic brain toxicity was minimal. In a second experiment, using drug-free polymer (n = 7), MST was 24 +/- 3 days. This was compared against an MST of 24 +/- 4 days in the tumor control group (n = 7) and 49 +/- 7 days in a cisplatin-polymer treated group (n = 6). In a third experiment, two doses of drug-free polymer and three doses of cisplatin-loaded polymer were tested in normal nontumor-bearing rats and found to be well tolerated.

CONCLUSIONS

Intralesional sustained release of cisplatin from biodegradable polymer is safe and effective for the treatment of brain 9L gliosarcoma in rats.

Intralesionally implanted cisplatin cures primary brain tumor in rats

BACKGROUND AND OBJECTIVES

Chemotherapy has added little to the overall survival of the patients with primary malignant brain tumors, primarily due to its difficulty penetrating the blood-brain barrier. Use of polymers, releasing high doses of chemotherapy locally over time, is a promising new treatment strategy. Three experiments were conducted to test the effect of cisplatin, released from biodegradable polymer, on rats with 1 week established brain tumor.

METHODS

9L gliosarcoma cells and drug-free or cisplatin-loaded polymer were administered through a right frontal lobe cannula in male Fischer 344 rats. Tumor cells were infused on day 0 and polymer on day 7. Animals were monitored for 60 days.

RESULTS

In experiment one, 0.5 mg/m2 of cisplatin loaded in polymer resulted in a mean survival time (MST) of 51 +/- 14 days with 63% (10/16) rats surviving to day 60. MST for the control group was 24 +/- 4 days (p = 2.5 x 10(-9)). Evidence of clinical or histologic brain toxicity was minimal. In a second experiment, using drug-free polymer (n = 7), MST was 24 +/- 3 days. This was compared against an MST of 24 +/- 4 days in the tumor control group (n = 7) and 49 +/- 7 days in a cisplatin-polymer treated group (n = 6). In a third experiment, two doses of drug-free polymer and three doses of cisplatin-loaded polymer were tested in normal nontumor-bearing rats and found to be well tolerated.

CONCLUSIONS

Intralesional sustained release of cisplatin from biodegradable polymer is safe and effective for the treatment of brain 9L gliosarcoma in rats.

Efficacy of intralesionally administered cisplatin-impregnated biodegradable polymer for the treatment of 9L gliosarcoma in the rat

OBJECTIVE

Use of biodegradable polymers for the local delivery of chemotherapy is a promising new strategy in the treatment of high-grade gliomas. We examine the benefit of local delivery of cisplatin, via biodegradable polymer, in the treatment of intracranial glioma in rats. This treatment is compared against intralesionally administered free cisplatin and systemic cisplatin.

METHODS

The Fischer 344 9L gliosarcoma rat model was used with a cannula placed in the right frontal lobe. On Day 0, 5 x 10(3) 9L gliosarcoma cells were infused. Treatment was initiated on Day 7. In Experiment 1, polymer alone was infused intralesionally to rule out any inherent toxic or tumoricidal properties. In Experiment 2, polymer impregnated with 0.5, 5.0, and 25 mg/m2 cisplatin was infused intralesionally. In Experiment 3, the most effective dose of drug containing polymer was compared against a similar dose of intralesionally administered free cisplatin and the systemic administration of cisplatin.

RESULTS

In Experiment 1, polymer alone demonstrated no inherent toxic or tumoricidal properties. In Experiment 2, polymer impregnated with 0.5 mg/m2 was 100% effective in eradicating intracranial tumor with minimal histological evidence of toxicity. At the 5.0 and 25 mg/m2 doses, local brain toxicity was significant. In Experiment 3, at Day 60, 8 of 12 animals treated with polymer containing 0.5 mg/m2 cisplatin were alive and tumor free. This compared with 3 of 13 tumor-free survivors for the group treated with intralesionally administered free cisplatin, and 0 of 13 and 0 of 11 survivors for the 50 and 100 mg/m2 intraperitoneally administered doses, respectively.

CONCLUSION

The local instillation of cisplatin-impregnated biodegradable polymer, allowing the sustained release of high-dose chemotherapy locally, seems to be effective treatment for intracranial 9L gliosarcoma in the rat. Treatment was superior to intralesionally administered free or systemic cisplatin.

[Measurement of blood NO contents using ESR method in rats after thermal injury]

The contents of nitric oxide (NO) in the blood were measured by electron spin resonance (ESR) method in Wistar rats with 35% TBSA III degrees burn. NO is endothelium derived relaxing factor (E-DRF) released by vascular endothelial cells. The results showed that: 1. Blood NO contents were not found to be significantly increased (72 hours postburn); 2. Escherichia coli lipopolysaccharide (LPS, endotoxin) could induce excessive NO formation in early burns.

[The changes in TNF alpha in plasma, organs and eschar of rats after thermal injury]

The TNF alpha (Tumor Necrosis Factor-alpha) contents in the plasma, five organs (heart, lung, liver, kidney and intestine) and burned skin were measured by ELISA method in Wistar rats with 35% TBSA III degrees. The animals were divided into eight different time groups. The experiment showed that TNF alpha contents were excessively high in early stage of burn (24 hours postburn) in plasma, eschar and the five organs. The contents of TNF alpha in eschar were 27.5-86.7 times higher than that in plasma and the five organs.