Effects of combined radiation and thermal burn injury on the survival of skin allograft and immune function in rats

OBJECTIVES

To investigate the effects of combined radiation and thermal burn injury on the survival of skin allografts and to analyze the relationship between the prolongation of allograft survival and the changes of immune functions of the thymocytes and splenocytes in rats.

METHODS

Wistar rats were irradiated with 3, 4, 5, 6 and 8 Gy of gamma rays. Thirty minutes after radiation, 15% TBSA III-degree burn was inflicted to the rats. Twenty-four hours after the burn injury, allografts were used to cover the burn wounds. In the 8 Gy group, 1 hour before skin grafting, the bone marrow cells (4 x 10(8)) from the same donor were also transplanted. All rats were carefully observed after injury. The rats with single radiation injury of 5 Gy gamma rays, with single burn injury and with combined radiation-burn injury were killed 3, 7, 10, 15 and 30 days after skin grafting for immunological assay and pathological study.

RESULTS

All the allografts in the single burn group were rejected in 10 days. In the combined injury groups, the survival rates of the allografts in rats undergoing 3 and 4 Gy radiation were 20% and 30%, respectively. In the combined injury groups undergoing 5, 6 and 8 Gy radiation, the 10-day survival rates of the allografts were 69%, 88% and 100% respectively, and the 30-day survival rates in the three groups were 36%, 42% and 100% separately. The grafted allogenic skin, with normal epithelial cells and good vascularity, healed well with the recipient's skin. Hairs grew well from the allografts 30 days after grafting. Three, 7 and 15 days after allografting, in the single burn group, the proliferative activities of the thymocytes were 90%, 185% and 130% of the preinjury level, and the antibody forming capacities of the splenocytes were 200%, 171% and 300% of the preinjury level, respectively; in the combined injury groups, the proliferative activities were 6%, 99% and 91% of the preinjury level, and the forming capacities were 2%, 36% and 90% of the preinjury level.

CONCLUSIONS

The survival rate of allograft in rats undergoing combined radiation and thermal burn injury rises with the increase in radiation dosage. The allograft covering single bun injury is severely rejected by immune reaction. The prolongation of the survival of allograft in combined injury group mainly results from radiation that suppresses immune functions.

Engineering of betabellin-15D: a 64 residue beta sheet protein that forms long narrow multimeric fibrils

The betabellin target structure is a beta-sandwich protein consisting of two 32 residue beta-sheets packed against one another by interaction of their hydrophobic faces. The 32 residue chain of betabellin-15S (HSLTAKIpkLTFSIAphTYTCAV pkYTAKVSH, where p=DPro, k=DLys, and h=DHis) did not fold in water at pH 6.5. Air oxidation of betabellin-15S provided betabellin-15D, the 64 residue disulfide bridged two-chain molecule, which also remained unfolded in water at pH 6.5. By circular dichroic spectropolarimetry, the extent of beta structure observed for betabellin-15D increased with the pH and ionic strength of the solution and the betabellin-15D concentration. By electron microscopy, in 5.0 mM MOPS and 0.25 M NaCl at pH 6.9, betabellin-15D formed long narrow multimeric fibrils. A molecular model was constructed to show that the dimensions of these betabellin-15D fibrils are consistent with a single row of beta-sandwich molecules joined by multiple intersheet H-bonds.

[A molecular epidemiologic study on the mechanism of intrauterine transmission of hepatitis B virus]

A case-control study with examination of placentas using immunohistochemistry stain was reported in this paper. In the Maternal and Children Health Hospital of Shanxi Province, 242 consecutive HBsAg positive mothers and their babies were selected as subjects and 110 placentas of HBsAg positive mothers and 25 placentas of HBsAg negative mothers during the different period of pregnancy were collected for laboratory test. The results showed that maternal HBeAg positivity (OR = 32.63) and history of threatened premature labor (OR = 22.80) were important risk factors. Among full-term placentas with HBsAg positivity, HBsAg (biomarker of HBV infection) positive rates were 100% in decidual cell, 59.38% in trophoblastic cell, 65.50% in villous mesenchyme cell, and 39.38% in villous capillary endothelial cell (VCEC) with a decreasing trend (trend test, chi 2 = 30.5, P < 0.01) from mothers to fetus whereas HBsAg positive in VCEC was significantly related to intrauterine infection (OR = 20.86, P < 0.01). Results suggested that there might be two transmission routes on the mechanism of HBV intrauterine transmission, hemogenous by damage of placental vessels and cellular through placental cellular transfer of HBV.

Development, progression, and androgen-dependence of prostate tumors in probasin-large T antigen transgenic mice: a model for prostate cancer

Probasin (PB) gene product is prostate-specific, epithelial cell in origin, and androgen-regulated. A large 12-kb promoter fragment of the PB gene (LPB) was linked to the simian virus 40 (SV40) large T antigen (Tag) deletion mutant (that removes the expression of the small t antigen) to deliver consistently high levels of transgene expression to the transgenic mouse prostate. Seven male founders, their male offspring, and all the male offspring from two female founders developed at least prostatic epithelial cell hyperplasia by 10 weeks of age, indicating that the incidence of transformation was 100%. Tumorigenesis in the LPB-Tag animals progressed in a manner similar to that observed in the human prostate. Initially, multifocal proliferating lesions were detected in the prostatic epithelium, which continued to progress into hyperplasia involving the entire epithelium and then low-grade dysplasia. Reactive stromal proliferation was induced and continued to develop throughout the progression to high-grade dysplasia, carcinoma in situ, and adenocarcinoma. Immunohistochemical studies indicated that most stromal cells stained positively for both androgen receptor and smooth muscle alpha-actin, suggesting that stromal overgrowth largely represented mesenchymal cells that had differentiated into smooth muscle cells. Epithelial cell transformation was accompanied by the down-regulation of differentiated function, as suggested by the loss of dorsolateral prostate-specific secretory proteins. Tumor growth was regarded as androgen-dependent because tumors regressed in animals castrated at 11 weeks of age, and androgen treatment restored both epithelial/stromal cell ratio and tumor growth. Furthermore, small populations of prostatic epithelial cells in castrated animals continued to proliferate, suggesting the potential for androgen-independent growth. Although prostatic metastasis to other organs was not observed, local invasion was detected. In summary, the LPB-Tag animal model is unique in that it is the only model generated with the Tag alone, thereby eliminating any influences of the small t antigen on prostate tumor formation. Moreover, this model undergoes molecular changes similar to those found in human prostate including: (a) the multi-focal nature of tumorigenesis, (b) the progressive histopathologic changes from low- to high-grade dysplasia similar to human prostatic intraepithelial neoplasia, (c) stimulation of reactive stromal proliferation, and (d) the androgen-dependent growth of the primary tumor. Thus, the LPB-Tag prostate tumor model will be useful for studying the sequential mechanisms underlying the development of multistep tumorigenesis.

[The study of presurgical and postsurgical orthodontic treatment of alveolar bone grafting on patients with complete cleft lip and palate]

OBJECTIVE

To investigate the patients who need the orthodontic treatment before and after alveolar bone grafting; the selection of the indications and so on.

METHODS

To select 20 patients with cleft lip and palate, each of them is treated by edgewise appliance, light-wire appliance or removable appliance half to one year before the operation.

RESULTS

After orthodontic treatment, the patients' maxillary teeth are drawn up in order; the distorted teeth have the right positions; the shape of the arch is normal and the teeth beside the cleft are no longer oblique. All of these give a good space to the grafted bone.

CONCLUSION

The orthodontic treatment before and after alveolar bone grafting is an important composition of serial treatment of cleft lip and palate. It not only gives a promise to the successful operation, but also makes patient a better shape and function of the occlusion.

Application of a Varied-Line-Spacing Grating in a High-Performance Soft X-ray Monochromator

The design and experimental evaluation of a high-resolution varied-line-spacing-grating monochromator constructed at the Photon Factory are described. Various applications of a varied-line-spacing grating in a high-performance soft X-ray monochromator are discussed.

A compact vacuum-ultraviolet beamline for synchrotron radiation photoelectron spectroscopy combined with an ion-scattering spectrometer, SORIS

Apparatus for high-resolution synchrotron radiation photoelectron spectroscopy combined with high-resolution medium-energy ion scattering, named 'SORIS', has been developed for simultaneous investigations of electronic states and atomic structures on surfaces. For this purpose, a compact vacuum-ultraviolet beamline of photon energy from 5 to 700 eV has been designed for the small storage ring 'Aurora' installed at Ritsumeikan University. Owing to the small electron-beam size in the storage ring, an energy resolution E/dE of >5000 can be obtained.

New wiggler beamlines at BSRF

A new multipole wiggler has been installed in the ring of the Beijing Electron Positron Collider (BEPC), and two new beamlines were extracted from it for experiments, including LIGA, microprobe fluorescence analysis, high-pressure diffraction and soft X-ray research. The beam profile and photon intensity were measured and compared with the calculated values. The main parameters and characteristics of the two beamlines are illustrated. Some experimental results are presented.

[Relationship between changes of phospholipid and lipid peroxide of erythrocyte membrane and diabetic retinopathy]

OBJECTIVE

To study the relation between the changes of phospholipid and lipid peroxide (LPD) in erythrocyte membrane in diabetes mellitus with the occurrence of diabetic retinopathy (DR).

METHODS

The levels of triglyceride (TG), cholesterol (TC), glycosylated hemoglobin (HbA(1)c), phosphatidylethanolamine (PE), phosphatidylinostiol (PI), phosphatidylserine (PS), phosphatidylcholine (PC), sphingomyelin (SM), lysophosphatidylcholine (LPC), lipid peroxide (LPO) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were investigated in 44 diabetic patients with DR, 20 diabetic patients with no DR (NDR) and 30 sex and age matched normal control subjects.

RESULTS

A significant decrease in PE, PI, PS, PC, SM, SOD and GSH-PX and a significant increase in LPC, LPO, TG, TC and HbA(1)c were detected in DR and NDR group when compared with the normal controls. These changes were more obvious in DR group.

CONCLUSION

The lipid peroxidation and the alteration of the erythrocyte membrane phospholipid compositions may contribute to the occurrence and development of DR.

[A research on chemical dynamic changes and drug efficacy of shengmaisan compound prescription: chemical researches on shengmaisan prescription(II)]

The content changes of 5-hydroxymethyl-2-furaldehyde(5-HMF), a new compound reported in the previous paper, in eight prescriptions of different composition were further determined by HPLC with a view to find the chemical dynamic changes and compatibility of medicines. The contents of 5-HMF in different combinations of Radix Ophiopogonis and Fructus Schisandrae, different boiling times and boiling frequency were examined. The results indicated that 5-HMF was produced in the boiling process of Radix Ophiopogonis and Fructus Schisandra combined. The contents of 5-HMF would increase with the increase of Radix Ophiopogonis amount, reaching the highest value after 1.5 h boiling and two times of boiling.

[Infrared spectra of Caulis Mahoniae and 6 species of medicinal plants of the same genus]

Based on the IR spectra of the petroleum ether extract, ethyl ether extract and water extract of Caulis Mahoniae and six species of medicinal plants of the same genus, it has been found out that the differences of chemical constituents among the samples can be reflected by the changes of IR spectra. This method can be used as a rapid and exact means to search unknown species with same chemical constituents in the same genus and family.

High-resolution spherical grating monochromator for the undulator beamline (BL-16B) at the Photon Factory

The design and performance of a 24 m high-resolution spherical grating monochromator (H-SGM) for the undulator beamline (BL-16B) at the Photon Factory are described. With three interchangeable gratings of 400, 900 and 2000 lines mm(-1), the H-SGM is designed to cover the photon energy range 40-600 eV. With a resolving power of approximately 2000 in the photon energy range 40-530 eV, more than 10(11) photons s(-1) have been measured. The best resolutions obtained so far, at a substantially lower photon flux, are greater than 10 000 at 250 eV and 8000 at 400 eV

Endogenous cellulases in animals: isolation of beta-1, 4-endoglucanase genes from two species of plant-parasitic cyst nematodes

beta-1,4-Endoglucanases (EGases, EC 3.2.1.4) degrade polysaccharides possessing beta-1,4-glucan backbones such as cellulose and xyloglucan and have been found among extremely variegated taxonomic groups. Although many animal species depend on cellulose as their main energy source, most omnivores and herbivores are unable to produce EGases endogenously. So far, all previously identified EGase genes involved in the digestive system of animals originate from symbiotic microorganisms. Here we report on the synthesis of EGases in the esophageal glands of the cyst nematodes Globodera rostochiensis and Heterodera glycines. From each of the nematode species, two cDNAs were characterized and hydrophobic cluster analysis revealed that the four catalytic domains belong to family 5 of the glycosyl hydrolases (EC 3.2.1, 3.2.2, and 3.2.3). These domains show 37-44% overall amino acid identity with EGases from the bacteria Erwinia chrysanthemi, Clostridium acetobutylicum, and Bacillus subtilis. One EGase with a bacterial type of cellulose-binding domain was identified for each nematode species. The leucine-rich hydrophobic core of the signal peptide and the presence of a polyadenylated 3' end precluded the EGases from being of bacterial origin. Cyst nematodes are obligatory plant parasites and the identified EGases presumably facilitate the intracellular migration through plant roots by partial cell wall degradation.

[The effect of HCV NS3 protein on expression of p53 gene protein in hepatocarcinogenesis]

OBJECTIVE

To investigate hepatocarcinogenesis by detecting the effect of HCV NS3 protein on expression of P53 protein in hepatocellular carcinoma (HCC) and pericarcinomatous liver tissue.

METHODS

The expression of HCV NS3 and P53 protein was detected by immuno-histochemical technique (SP method) in specimens of HCC and their surrounding liver tissues from 47 patients with negative HBV.

RESULTS

The positive rate of HCV NS3 protein was lower in HCC(62%) than in pericarcinomatous liver tissue(83%) (P < 0.025). The expressive strength of HCV NS3 protein in HCC was related to the degree of carcinomatous cell differentiation(P < 0.025). The positive rate of P53 protein in carcinomatous tissue(81%) was higher than in pericarcinomatous liver tissue (47%)(P < 0.025). The worse differentiation of cancer cells, the stronger expression of P53 protein (P < 0.05). The expression of P53 protein was not correlated with the expression of HCV NS3 protein in carcinomatous tissiue (P > 0.5), whereas their expression was closely related in pericarcinomatous liver tissue(P < 0.01), and the expressive rate of P53 protein in the cases of positive HCV NS3 protein was higher than that in the cases of negative HCV NS3 protein.

CONCLUSION

HCV NS3 protein may exert its hepatocarcinogenic effect in early stage on host cells by endogenous pathway which may bring about mutation of p53 gene and transformation of hepatocytes.

Complex of NS3 protease and NS4A peptide of BK strain hepatitis C virus: a 2.2 A resolution structure in a hexagonal crystal form

The crystal structure of the NS3 protease of the hepatitis C virus (BK strain) has been determined in the space group P6(3)22 to a resolution of 2.2 A. This protease is bound with a 14-mer peptide representing the central region of the NS4A protein. There are two molecules of the NS3(1-180)-NS4A(21'-34') complex per asymmetric unit. Each displays a familiar chymotrypsin-like fold that includes two beta-barrel domains and four short alpha-helices. The catalytic triad (Ser-139, His-57, and Asp-81) is located in the crevice between the beta-barrel domains. The NS4A peptide forms an almost completely enclosed peptide surface association with the protease. In contrast to the reported H strain complex of NS3 protease-NS4A peptide in a trigonal crystal form (Kim JL et al., 1996, Cell 87:343-355), the N-terminus of the NS3 protease is well-ordered in both molecules in the asymmetric unit of our hexagonal crystal form. The folding of the N-terminal region of the NS3 protease is due to the formation of a three-helix bundle as a result of crystal packing. When compared with the unbound structure (Love RA et al., 1996, Cell 87:331-342), the binding of the NS4A peptide leads to the ordering of the N-terminal 28 residues of the NS3 protease into a beta-strand and an alpha-helix and also causes local rearrangements important for a catalytically favorable conformation at the active site. Our analysis provides experimental support for the proposal that binding of an NS4A-mimicking peptide, which increases catalytic rates, is necessary but not sufficient for formation of a well-ordered, compact and, hence, highly active protease molecule.

[A research on chemical dynamic changes and drug efficacy of SMS compound prescription: chemical researches on shenmaisan prescription (I)]

To clarify the material base of the distinct curative effect of Shengmaisan (SMS) compound prescription, a study was made on the dynamics of chemical constituents in the decoction prepared according to the compound prescription. From the decoction a new compound was isolated and identified by UV, IR, MS and NMR as 5-hydroxymethy-2-furaldehyde (5-HMF). The study suggests that the distinct curative effect of SMS compound prescription hinges on a material base which is different chemically from that in the other three single drugs used separately, thus presenting scientific criteria for rational compatibility and quality check in making preparations on compound prescriptions.

Transmission and natural regulation of infection with Ascaris lumbricoides in a rural community in China

A longitudinal study on a cohort of 215 people who remained untreated from June 1993 to June 1994 was carried out using fecal egg counts to examine the course of transmission and aspects of the natural regulation of the infection with Ascaris lumbricoides. The results indicate that the parasite population remained relatively stable during the years since overall prevalence remained steady above 60%. About 40% of the people in the cohort retained their infection intensity status throughout the year, in terms of light, medium, and heavy infections. The regulation of infection in the population could be attributed to the tendency for the loss of worms from people with initial light infections and the movement to medium infection intensity status of people with both light and heavy infections. Compared with adults, children showed a stronger tendency of retaining initial medium infections but weaker tendencies for keeping initial light infections and clearing themselves of infection. Predisposition to light and medium infections was detected in people who had experienced an uninfected period of 4-12 mo before reinfection was established.

[Effect of hypoxia on proliferation and alpha 1 (I) procollagen gene expression by human fetal lung fibroblasts]

OBJECTIVE

The effect of 2% hypoxia on the proliferation and alpha 1(I) procollagen gene expression by human fetal lung fibroblast was studied.

METHODS

Cell proliferation was determined by cell counting and nonradioactive cell proliferation assay method. alpha 1(I) procollagen gene expression was detected by Northern blot hybridization analysis.

RESULTS

Cell number and 490 nm OD expressing low oxygen values were markedly increased by the 24, 48 and 72 h exposure to 2% hypoxia respectively. An obvious increase of the alpha 1(I) procollagen mRNA expression was detected after 24 h exposure to 2% hypoxia. The increase of gene expression could be inhibited by Ligustrazin (30 micrograms/ml, 10 micrograms/ml).

CONCLUSIONS

2% hypoxia plays an important role in the outcome of wound healing and pulmonary vascular remodeling by affecting the function of human fetal lung fibroblasts.

On-line pretreatment and determination of Pb, Cu and Cd at the microgram l-1 level in drinking water by chelation ion chromatography

A novel, highly sensitive method for the simultaneous separation and determination of lead, copper, cadmium and other transition metals in drinking water was achieved by on-line sample pretreatment of chelation ion chromatography. Manganese, which coeluted with cadmium, was oxidized to permanganate by ammonium persulfate before injection. Permanganate, with bulk quantity of alkali, alkaline earth metals, iron and aluminum, was eliminated by pyrophosphoric acid-ammonium acetate buffer solution (pH 5.5), while retaining heavy and transition metals on a selective chelating resin (MetPac CC-1 column). Then, they were disabsorbed and transferred to a sulfonated cation exchanger (TMC-1 column). Finally, the concentrated trace metals were separated on a bifunctional ion-exchange column (CS5A) by a concentration gradient of oxalic acid and sodium nitrate eluents, coupled with post-column spectrophotometric detection with 2-[(5-bromo-2-pyridyl)azo]-5-diethylaminophenol (5-Br-PADAP) at 560 nm. The separation and color-development conditions were optimized. The detection limits for the method (signal-to-noise ratio = 3:1) were at or below the microgram l-1 level. The results of drinking water analyses were satisfactory.

Development, progression, and androgen-dependence of prostate tumors in probasin-large T antigen transgenic mice: a model for prostate cancer

Probasin (PB) gene product is prostate-specific, epithelial cell in origin, and androgen-regulated. A large 12-kb promoter fragment of the PB gene (LPB) was linked to the simian virus 40 (SV40) large T antigen (Tag) deletion mutant (that removes the expression of the small t antigen) to deliver consistently high levels of transgene expression to the transgenic mouse prostate. Seven male founders, their male offspring, and all the male offspring from two female founders developed at least prostatic epithelial cell hyperplasia by 10 weeks of age, indicating that the incidence of transformation was 100%. Tumorigenesis in the LPB-Tag animals progressed in a manner similar to that observed in the human prostate. Initially, multifocal proliferating lesions were detected in the prostatic epithelium, which continued to progress into hyperplasia involving the entire epithelium and then low-grade dysplasia. Reactive stromal proliferation was induced and continued to develop throughout the progression to high-grade dysplasia, carcinoma in situ, and adenocarcinoma. Immunohistochemical studies indicated that most stromal cells stained positively for both androgen receptor and smooth muscle alpha-actin, suggesting that stromal overgrowth largely represented mesenchymal cells that had differentiated into smooth muscle cells. Epithelial cell transformation was accompanied by the down-regulation of differentiated function, as suggested by the loss of dorsolateral prostate-specific secretory proteins. Tumor growth was regarded as androgen-dependent because tumors regressed in animals castrated at 11 weeks of age, and androgen treatment restored both epithelial/stromal cell ratio and tumor growth. Furthermore, small populations of prostatic epithelial cells in castrated animals continued to proliferate, suggesting the potential for androgen-independent growth. Although prostatic metastasis to other organs was not observed, local invasion was detected. In summary, the LPB-Tag animal model is unique in that it is the only model generated with the Tag alone, thereby eliminating any influences of the small t antigen on prostate tumor formation. Moreover, this model undergoes molecular changes similar to those found in human prostate including: (a) the multi-focal nature of tumorigenesis, (b) the progressive histopathologic changes from low- to high-grade dysplasia similar to human prostatic intraepithelial neoplasia, (c) stimulation of reactive stromal proliferation, and (d) the androgen-dependent growth of the primary tumor. Thus, the LPB-Tag prostate tumor model will be useful for studying the sequential mechanisms underlying the development of multistep tumorigenesis.

The bacterial inhibitory ability and in vivo drug release pattern of a new drug delivery system: ciprofloxacine/tricalcium phosphate delivery capsule

The bacterial inhibitory ability of a new drug delivery system (DDS): Ciprofloxacine/tricalcium phosphate delivery capsule (CTDC), its in vivo drug release pattern, and the influence of ultrasonic irradiation on its drug release were investigated. It was found that CTDC had a strong and sustained inhibitory ability to some common pathogens of bone and joint infections, such as staphylococcus aureus, escherichia coli and pseudomonas aeruginosa. In vivo drug-release study in animals demonstrated a high concentration of ciprofloxacine in the bone tissue surrounding CTDC which was placed in the greater trochanter of the rabbit and continued to release ciprofloxacine for at least 5 weeks and the blood level of ciprofloxacine was low. In vivo study also showed ultrasonic irradiation could increase the amount of ciprofloxacine released from CTDC, which may be an economical, effecient and safe new method to achieve the control of drug release from DDS.

Biodegradation of tricalcium phosphate ceramics by osteoclasts

Biodegradation of tricalcium phosphate (TCP) ceramics was observed through mixed culture of osteoclasts and TCP discs in vitro in this study. Osteoclasts were isolated from newborn SD rat's marrow of long bone and cultured on TCP discs. The culture terminated at the 48th h and 96th h respectively. Under an inverted microscope, the osteoclasts imparted round or oval body with multinuclear and many thin processes. These cells were positively stained for tartrate-resistance acid phosphatase (TRAP). Scanning electron microscope showed that many resorption lacunae on TCP disc surface and their diameters were smaller than 20 microns. Osteoclasts were located in the lacunae. At the 96th h, the resorption lacunae become larger and osteoclasts showed degeneration. It is suggested that osteoclasts possess ability to re-absorb TCP ceramics under in vitro culturing condition.

X-ray lens of monolithic polycapillaries for macromolecular crystallography

The monolithic polycapillary X-ray Lens is a fast developing optics that has many applications in different fields, one of them, described in this paper, is a successful application in the X-ray diffraction for macromolecular crystallography. The direct beam intensity irradiating on crystal with usage of the monolithic X-ray lens was increased 1 to 2 order of magnitude more than the traditional method with the double focusing mirrors. the diffracted X-ray intensity was increased more than about 8 times, the resolution was improved by 0.2–0.6Å, and the signal to noise ratio was also improved. The measuring time became shorter. The crystal samples which had to be analyzed by synchrotron before are able to be investigated in routine laboratory now.

Studies on the microsomal cytochrome P450s in the livers of carcinogen-resistant and sensitive rats during long-term administration of 3'-methyl-4-dimethylaminoazobenzene

Time-course studies on the microsomal cytochrome P450s in the livers of carcinogen-resistant (DRH) and sensitive (Donryu) rats were carried out during a long-term administration of 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). Total contents of the microsomal cytochrome P450s were gradually reduced with time in the Donryu rat livers, while those in the DRH rats did not alter significantly under these conditions. The activities of several isoforms of cytochrome P450 (CYP1A1, CYP1A2, and CYP2E1) were determined separately during these experimental periods. However, we could not obtain satisfactory evidence which may explain the different susceptibility to chemical carcinogenic actions in the livers between DRH and Donryu rats. Lower total contents of cytochrome P450s in the Donryu rats during the later stage may be due to the hepatic injuries caused by long-term administration of 3'-Me-DAB.

New DNA minor-groove binding molecules with high sequence-selectivities and binding affinities

New DNA minor-groove binding molecules with high binding affinities and sequence-selectivities are described. The effects of structural changes in ligands with a three-ring backbone on their DNA-binding properties have been studied. Of a pool of eight potential ligands, two showed binding affinities and sequence-selectivities rivaling distamycin. The two best ligands share a common structural motif that involves a para-di-substituted benzene ring flanked by two meta-di-substituted benzene rings.

Discussion on the relationship between normal hematocrit and geographical factors in China

This paper is written in order to provide a scientific basis for laying out an unified standard of the reference value of hematocrit of Chinese healthy people. It studies the relationship between the reference values of Chinese adults' hematocrit, tested according to the Wintrobe Laws and five geographical factors. It is found that the altitude is the most important factor affecting the reference value of Chinese healthy people's hematocrit. As the altitude gradually increases, the reference value of their hematocrit also increases. By using the method of stepwise regression analysis, two multivariate regression equations are deduced. If the geographical index values in a particular area are known, the reference value of Chinese healthy people's hematocrit in this area can be established by means of the regression equations. Furthermore, according to the dependent relationship of the reference value of Chinese healthy people's hematocrit to geographical factors, China can be divided into six districts: Qingzang, Southwest, Northwest, Southeast, North and Northeast district.

[A simple, rapid method to isolate cardiac myocytes from rat and guinea-pig]

A simple, rapid method to isolate cardiac myocytes from rat and guinea-pig was described by using this method. Morphologically intact and calcium tolerant single myocytes were obtained. The myocytes were suited well for various electrophysiological recording especially in patch clamp study.

Conserved enhancer elements in human and mouse renin genes have different transcriptional effects in As4.1 cells

Despite the strong conservation of proximal 5'-flanking DNA sequences, cell transfection and transgenic animal studies have failed to provide a unifying hypothesis to explain the expression of both mouse and human renin genes. Recently, sequences contained in the mouse Ren-1c gene 5'-flanking DNA (-2866 to -2625) were shown to contain an enhancer-like element that stimulates Ren-1c promoter activity in renin-expressing As4.1 cells approximately 80-fold. Earlier studies using transgenic mice had suggested that this same region is required for the cell-specific expression of mouse renin genes. Since existing human renin genomic clones lack sequences homologous to the mouse renin enhancer, we isolated several human P1 and P1 artificial chromosome genomic clones that contain > 80 kb spanning the human renin gene. Analysis of these clones by Southern blot hybridization and long-rang polymerase chain reaction showed that they contain sequences homologous to the mouse enhancer at approximately 12 kb upstream of the transcription start site. Mouse and human sequences were 59% identical over a 650-bp region that contained the minimal enhancer from the mouse Ren-1c gene. However, a 1-kb fragment containing the entire human enhancer homology failed to stimulate human renin promoter activity in transiently transfected As4.1 cells. Further deletional analysis showed that a 220-bp region of the human sequence highly conserved in the mouse Ren-1c gene exhibited up to 47-fold transcriptional stimulation, although this was lower than the maximal effect exhibited by the minimal mouse enhancer (223-fold). Taken together, these observations suggest that sequences surrounding the conserved enhancer core stimulate enhancer activity in the mouse gene but suppress activity in the human gene. The high transcriptional activity of the mouse enhancer may have evolved to support the exceptionally high plasma renin concentrations found in mice. However, the enhancer core and surrounding conserved sequences may play an additional role in directing cell specificity.

[Effects of locally used SD zinc, SD silver and skin transplantation on the combined radiation-burn injury in the rat]

Effects of local use of sulfadiazine (SD) zinc, SD silver in the wound and skin transplantation on the combined injury of 6 Gy radiation and 15% TBSA burn were investigated in the present study. In the three groups of SD zinc or SD silver plus skin grafting at 15 d after combined injury and SD zinc alone, the 15-day survival rates were 63%, 69% and 75% respectively, and significantly higher than that of control group (42%). The repair time of burn wound was shorter and the number of white blood cells was lower than that of control. Animals in the group of local use of SD silver followed by skin grafting on the 7th day all died, but all of the animals survived when the skin grafting was performed after 15 days. These results suggested that SD zinc and SD silver showed some therapeutic effects on the combined radiation-burn injury. In critical phase of the combined injury, surgical operation should be prohibited. However, in the recovery phase, skin transplantation could be performed.

Developed, binary, image processing in a dual-channel, optical, real-time morphological processor

A developed, binary, image-processing technique is proposed, and a dual-channel, optical, real-time morphological processor is developed. Nine binary image processings can be realized fully in parallel. The measures for compensating scale and rotation distortion for pattern recognition are provided. Some applications of optical, morphological binary image processing are studied and experimental results are listed.

[Effects of yizhi pills on memory, superoxide dismutase and malondialdehyde of brain and immunity in mice]

Passive avoidance tests have shown that Yizhi Pills (YZ) markedly improve the memory of normal mice at a dose of 100 mg/kg after oral administration for fifteen days, and significantly reverse the scopolamine, NaNO2 and EtOH-induced disruptions of memory retention in mice at doses of 100, 200, 500 mg/kg after oral administration for five days. In aged mice induced by D-galactose, YZ also significantly improve the impaired memory, increase the activity of SOD and decrease the content of MDA in brain. All these effects were observed at doses of 200, 500 mg/kg after oral administration for forty-one days. YZ significantly promote blood carbon particle clearance, enhance hemolysin antibody in immunodepressed mice induced by cyclophosphamide, and increase earswelling in immunodepressed mice induced by prednisolonum.

[Effects of SAD on cytogenetics of mouse embryonic cells and its embryo development]

We report here that SAD may not only suppress transcription activity of rRNA genes, but also increase SCE frequency of mouse embryonic cells, leading to bloching of the embryo development and fetal death, and finally significant decrease of birth percentage of the new born offsprings. Ata concentration of SAD in 10(-5)mol/L, the transcription activity of rRNA genes was decreased to 15% of the normal level, and the SCE frequency was increased doubly, leading to that the birth percentage was decreased to 50% of normal one. When SAD concentration of 10(-3)mol/L was used the transcription activity of rRNA genes was completely suppressed and SCE frequency was increased to as 4.8 times high as normal, leading to that the birth percentage dropped to 4% from 100%. Our results indicates that both the cytogenetic effects and the inhibition of the embryonic cells are directly proportional to the SAD concentration used. The relationship between the change of both the rRNA gene transcription and SCE frequency and the degree of embryo development are also discussed preliminarily.

Clinical treatment planning optimization by Powell's method for gamma unit treatment system

PURPOSE

This article presents a new optimization method for stereotactic radiosurgery treatment planning for gamma unit treatment system.

METHODS AND MATERIALS

The gamma unit has been utilized in stereotactic radiosurgery for about 30 years, but the usual procedure for a physician-physicist team to design a treatment plan is a trial-and-error approach. Isodose curves are viewed on two-dimensional computed tomography (CT) or magnetic resonance (MR) image planes, which is not only time consuming but also seldom achieves the optimal treatment plan, especially when the isocenter weights are regarded. We developed a treatment-planning system on a computer workstation in which Powell's optimization method is realized. The optimization process starts with the initial parameters (the number of isocenters as well as corresponding 3D isocenters' coordinates, collimator sizes, and weight factors) roughly determined by the physician-physicist team. The objective function can be changed to consider protection of sensitive tissues.

RESULTS

We use the plan parameters given by a well-trained physician-physicist team, or ones that the author give roughly as the initial parameters for the optimization procedure. Dosimetric results of optimization show a better high dose-volume conformation to the target volume compared to the doctor's plan.

CONCLUSION

This method converges quickly and is not sensitive to the initial parameters. It achieves an excellent conformation of the estimated isodose curves with the contours of the target volume. If the initial parameters are varied, there will be a little difference in parameters' configuration, but the dosimetric results proved almost to be the same.

Hepsin, a cell surface serine protease identified in hepatoma cells, is overexpressed in ovarian cancer

Extracellular proteases mediate the digestion of neighboring extracellular matrix components in initial tumor growth, allow shedding or desquamation of tumor cells into the surrounding environment, provide the basis for invasion of basement membranes in target metastatic organs, and are required for release and activation of many growth and angiogenic factors. We identified overexpression of the serine protease hepsin gene in ovarian carcinomas and investigated the expression of this gene in 44 ovarian tumors (12 low malignant potential tumors and 32 carcinomas) and 10 normal ovaries. Quantitative PCR was used to determine the relative expression of hepsin compared to that of beta-tubulin. The mRNA expression levels of hepsin were significantly elevated in 7 of 12 low malignant potential tumors and in 27 of 32 carcinomas. On Northern blot analysis, the hepsin transcript was abundant in carcinoma but was almost never expressed in normal adult tissue, including normal ovary. Our results suggest that hepsin is frequently overexpressed in ovarian tumors and therefore may be a candidate protease in the invasive process and growth capacity of ovarian tumor cells.

[Applied anatomy of the submental vessels and submental flaps]

To search ideal flaps for facial defect repair, the authors performed dissection in the submental region of 20 cadavers. Different methods were used in the anatomic study. It is concluded that 1. there is a submental artery and two concomitant veins on each side of the submental region; 2. four types of flaps can be formed; 3. the flap can be transferred as a free or pedicled flap; 4. while creating the flap, the anterior belly of the bigastric muscle should be included and the branches of the facial nerve and inferior alveolar nerve must be protected. With the well-matched color and texture, the flap of the submental region is suitable for facial defect repair.

Large fragment of the probasin promoter targets high levels of transgene expression to the prostate of transgenic mice

BACKGROUND

Androgen regulation and prostate-specific expression of targeted genes in transgenic mice can be controlled by a small DNA fragment of the probasin (PB) promoter (-426 to +28 base pairs, bp). Although the small PB fragment was sufficient to direct prostate-specific expression, the low levels of transgene expression suggested that important upstream regulatory sequences were missing.

METHODS

To enhance transgene expression, a large fragment of the PB promoter (LPB, -11,500 to +28 bp) was isolated, linked to the bacterial chloramphenicol acetyl transferase (CAT) gene, and microinjected into CD1 mouse oocytes to generate transgenic mouse lines.

RESULTS

As shown by the immunohistochemical studies, CAT gene expression was restricted to the prostatic epithelial cells in a tissue-specific manner. High levels of CAT gene expression were observed in two of the six LPB-CAT transgenic lines. In Line 1, developmental regulation of LPB-CAT was detected early, from 1 to 4 weeks of age, with the activity of CAT increasing from 3 to 40,936 dpm/min/mg protein. Upon sexual maturation and elevated serum androgen levels (7 weeks of age), a further 18-fold rise in CAT activity occurred. Hormone ablation by castration in mature mice dramatically reduced transgene expression, whereas treatment with androgens returned LPB-CAT expression to precastration levels. In contrast, treatment with glucocorticoids had no significant effect on CAT gene expression. Zinc treatment of the castrated animals also increased LPB-CAT expression three- to four-fold in two prostatic lobes.

CONCLUSIONS

This study demonstrates that important regulatory DNA sequences located in the LPB fragment contribute to tissue-specific expression and greatly increase levels of transgene expression induced by androgens and zinc.

[Applied anatomy of the vessels in the dorsum of the finger]

Twenty adult cadavers were used to study the vessels of the flag flap in the dorsum of the finger with careful dissection and measurement. The results indicate: 1. The main blood supply to the dorsum of the finger comes from the cutaneous branches of the proper palmar digital artery. The dorsal digital artery is short and small, taking part in the blood supply of the dorsal digital skin of the proximal phalanges. 2. The veins communicate with each other, forming the first, the second and the third venous arch at the level of the distal phalangeal joint, the proximal phalangeal joint and the middle of the proximal phalanges. 3. The third venous arch is big. Proximally, the veins grouped to form radial and ulnar trunks, which communicate with the dorsum veins. 4. There are almost no veins in the area between the radial and ulnar venous trunk, which might be called the "vein lacking area." 5. The venous trunk, radial or ulnar, locates 4.1 +/- 0.1 mm from the midline of the finger dorsum at the middle of the proximal phalanges, and 5.2 +/- 0.2 mm at the metacarpophalangeal joint. Based on the results, we described the anatomical characteristics, the principle of design and the survival mechanism of the flag flap.

Inhibition of protein phosphatase activity induces p53-dependent apoptosis in the absence of p53 transactivation

Inhibitors of type 1 and type 2A protein phosphatases were used to examine the involvement of protein phosphorylation in regulating the functions of endogenous p53. Exposure of Balb/c 3T3 cells to okadaic acid, an inhibitor of protein phosphatases 1 and 2A, increased the phosphorylation of p53 without changing p53 levels. Okadaic acid treatment enhanced the binding of p53 to a consensus DNA target sequence and caused a 5-8-fold increase in p53 transcriptional activity. Transient expression of SV40 small tumor antigen, a specific inhibitor of protein phosphatase 2A, caused a 4-fold increase in p53 transcriptional activity. Incubation of Balb/c 3T3 cells with okadaic acid also induced programmed cell death in a dose- and time-dependent manner. Decreases in viability, morphological changes, and the appearance of DNA fragmentation were dependent on p53 since cells lacking functional p53 were resistant to okadaic acid-induced apoptosis. The p53-dependent apoptosis induced by okadaic acid was rapid and did not require p53 transcriptional activity. The fact that SV40 small tumor antigen did not induce apoptosis provides additional evidence that p53 transcriptional activity is not sufficient for p53-mediated apoptosis. These results indicate that signaling pathways involving protein phosphorylation play critical roles in controlling the apoptotic activity of p53. Furthermore, a basal level of protein phosphatase 1 or 2A activity is necessary to prevent p53-dependent apoptosis.

How does the W434F mutation block current in Shaker potassium channels?

The mutation W434F produces an apparently complete block of potassium current in Shaker channels expressed in Xenopus oocytes. Tandem tetrameric constructs containing one or two subunits with this mutation showed rapid inactivation, although the NH2-terminal inactivation domain was absent from these constructs. The inactivation showed a selective dependence on external cations and was slowed by external TEA; these properties are characteristic of C-type inactivation. Inactivation was, however, incompletely relieved by hyperpolarization, suggesting the presence of a voltage-independent component. The hybrid channels had near-normal conductance and ion selectivity. Single-channel recordings from patches containing many W434F channels showed occasional channel openings, consistent with open probabilities of 10(-5) or less. We conclude that the W434F mutation produces a channel that is predominantly found in an inactivated state.

Reaction of a platinum(IV) complex with native Cd,Zn-metallothionein in vitro

The first observation of a redox process following a substitution reaction between a platinum(IV) complex K2PtCl6 with rabbit liver native Cd,Zn-MT is presented. The reaction features and products are studied by UV-visible and circular dichroism spectroscopy, chromatography, and X-ray photoelectron spectroscopic measurements. It is a significant complicated reaction comprising redox and substitution reactions. The reaction generates monomeric and dimeric products, and higher oligomers precipitate with intra- or intra- and intermolecular CyS-SCy linkages. Pt(IV) is reduced to Pt(II), which then binds to the monomeric and dimeric products, and may also bind to higher oligomers. The beta-cluster is more reactive than the alpha-cluster, and reacts first with K2PtCl6. Cd5Pt2 and Cd4Pt4 were found when native Cd,Zn-MT reacted with 2 and 4 molar equivalents of Pt(IV) for 2 h in which four Cd ions were located in the alpha-cluster. The amounts of Cd and Pt ions decreased in both monomeric and dimeric products when the reaction was prolonged and intramolecular CyS-SCy linkages increased. Besides the oligomers which precipitated, only dimeric products were formed when the reaction molar ratio of Pt(IV) to MT was more than 10:1. Cd3Pt6 and Cd1Pt8 were obtained when the reaction occurred for 2 and 72 h, respectively. The structure of the clusters may exist when native Cd, Zn-MT reacts with substoichiometric quantities of K2PtCl6 (< 0.5 K2PtCl6 per MT thiolate) for a short time (2 h), but may be partly disrupted with stoichiometric or excess quantities of K2PtCl6 (> or = 0.5 K2PtCl6 per MT thiolate) for a long time. The disruption of the cluster structures results in an increase of the nonbridge thiolate and an increase of the binding sites to Pt ions. The mechanism of the antitumor activity and developing drug resistance of Pt(IV) complex drugs is discussed.

Interaction of sodium chloroplatinate and iproplatin with metallothionein in vivo

The abilities of platinum(IV) complexes to induce the biosynthesis of metallothionein (MT) were investigated in rabbits given injections s.c. of sodium chloroplatinate (Na2PtCl6) and iproplatin (cis-dichloro-bis-isopropylamine-trans-dihydroxylplatinum IV). It is revealed for the first time that both complexes can induce MT synthesis in the liver and the kidney, but the induction ability was weaker compared to Zn2+ compounds. The induced MT was purified and identified. The hepatic MT resulting from Na2PtCl6 injection only contained Zn, whereas the hepatic MT from iproplatin injection and the renal MT from injection of both complexes contained 4-5 Zn and 1-2 Pt per mole of protein, and the renal MT also contained 1-2 Cu per mole of protein. The oxidation state of platinum in the MT is +2 as determined by X-ray photoelectron spectroscopic measurements. Pretreatment with Zn(NO3)2 elevated the levels of MT, but the binding of Pt to MT was significantly less compared to that without Zn(NO3)2 pretreatment. The data obtained from the amino acid composition analysis were consistent with the theoretical values. Upon these bases, the role of MT in relation to its involvement in the metabolism of Pt(IV) complexes and the mechanism of drug resistance to the Pt(IV) complexes as antitumor agents are discussed.

RGS4 inhibits Gq-mediated activation of mitogen-activated protein kinase and phosphoinositide synthesis

Recombinant regulators of G protein-signaling (RGS) proteins stimulate hydrolysis of GTP by alpha subunits of the Gi family but have not been reported to regulate other G protein alpha subunits. Expression of recombinant RGS proteins in cultured cells inhibits Gi-mediated hormonal signals probably by acting as GTPase-activating proteins for Galphai subunits. To ask whether an RGS protein can also regulate cellular responses mediated by G proteins in the Gq/11 family, we compared activation of mitogen-activated protein kinase (MAPK) by a Gq/11-coupled receptor, the bombesin receptor (BR), and a Gi-coupled receptor, the D2 dopamine receptor, transiently co-expressed with or without recombinant RGS4 in COS-7 cells. Pertussis toxin, which uncouples Gi from receptors, blocked MAPK activation by the D2 dopamine receptor but not by the BR. Co-expression of RGS4, however, inhibited activation of MAPK by both receptors causing a rightward shift of the concentration-effect curve for both receptor agonists. RGS4 also inhibited BR-stimulated synthesis of inositol phosphates by an effector target of Gq/11, phospholipase C. Moreover, RGS4 inhibited inositol phosphate synthesis activated by addition of AlF4- to cells overexpressing recombinant alphaq, probably by binding to alphaq.GDP.AlF4-. These results demonstrate that RGS4 can regulate Gq/11-mediated cellular signals by competing for effector binding as well as by acting as a GTPase-activating protein.

[Chest CT and its assessment of resectability in lung cancer]

OBJECTIVE

To evaluate chest CT and its relation to possible surgical resection in lung cancer patients.

METHODS

Ninty-five patients who were diagnosed and confirmed as having lung cancers by surgery and pathology were divided into three groups: (1) Radical resection group; (2) Palliative resection group and (3) Thoractomy group. The diameter of the tumor, the proximity to mediastinum and/or the hilum and the invasion of their lymph nodes were measured. Meanwhile, the changes in the mediastinum and thoracic cavity on the chest CT were noted in these three groups.

RESULTS

The diameter of the tumor in each group was 4.10 +/- 1.75, 3.90 +/- 1.20, 5.20 +/- 3.66 (cm, mean +/- s, P > 0.05). The proximity to the mediastinum and/or the hilum and the invasion of their lymph nodes was 2.68 +/- 1.60, 4.02 +/- 1.56, 4.85 +/- 3.28 (cm, mean +/- s, P < 0.01, P < 0.05). The characteristic change in the thoractomy group is deformity in the lymph nodes in the mediastinum and hilum.

CONCLUSION

There is no obvious relation between the diameter of the lumg tumor and surgical resection, but the proximity to the mediastinum and/or the hilum and the invasion of their lymph nodes is an important factor. It is possible to perform a radical resection when its contact is less than 2.68 +/- 1.60 cm. Obvious deformity of the mediastinal structures and the hilum is a contraindication for lung cancer surgery.

Ablation of the CDK inhibitor p57Kip2 results in increased apoptosis and delayed differentiation during mouse development

p57(Kip2) is a paternally imprinted gene that encodes a potent inhibitor of several cyclin/Cdk complexes. p57(Kip2) is primarily expressed in terminally differentiated cells, associates with G1 Cdks, and can cause cell cycle arrest in G1 phase. To investigate the role of p57(Kip2) in vivo, we have ablated the p57(Kip2) gene by homologous recombination in ES cells and generated mice devoid of p57(Kip2) expression. Most p57(Kip2) null mice die after birth and display severe developmental defects with varying degrees of penetrance. As expected, heterozygous mice that inherit a maternal, but not a paternal, targeted allele exhibit similar deficiencies and neonatal death. Developmental defects of p57(Kip2) mutant mice include cleft palate and gastrointestinal abnormalities ranging from an inflated GI tract to loss of the jejunum and ileum. These tissues display a significant increase of apoptotic cells in the absence of p57(Kip2). Most p57(Kip2) mutant mice have short limbs, a defect attributable to abnormal endochondral ossification caused by delayed cell cycle exit during chondrocyte differentiation. A similar defect has been observed in mice lacking p107 and p130, thus suggesting that p57(Kip2) might be an upstream regulator of these Rb-related proteins. The p57(Kip2) locus has been implicated in the Beckwith-Wiedemann syndrome and in the development of sporadic Wilms' tumors and lung carcinomas. To date, we have not observed neoplastic development even in those p57(Kip2) mutant mice that have survived for >5 months of age. These findings indicate that p57(Kip2) has an important role during mouse development that cannot be compensated by other Cdk inhibitors.

Molecular characterization of TUB, TULP1, and TULP2, members of the novel tubby gene family and their possible relation to ocular diseases

Tubby, an autosomal recessive mutation, mapping to mouse chromosome 7, was recently found to be the result of a splicing defect in a novel gene with unknown function. Database searches revealed that sequences corresponding to the C terminus of the tub protein were highly conserved across a number of species including humans, mice, Caenorhabditis elegans, Arabidopsis, rice, and maize, and that tub was a member of a gene family. We describe here, TUB, the human homolog of mouse tub, and two newly characterized family members, TULP1 for tubby like protein 1 and TULP2. These three family members, which differ in the N-terminal half of the protein, share 60-90% amino acid identity across their conserved C-terminal region and have distinct tissue expression patterns. Alternatively spliced transcripts with 5' variable sequences, three of which have been identified for the tubby gene, may mediate tissue specific expression. We also report that TUB, TULP1, and TULP2 map to human chromosomes 11p15.4, 6p21.3, and 19q13.1, respectively. TULP1 and TULP2 map within the minimal intervals identified for retinitis pigmentosa 14 on chromosome 6p21.3 and cone-rod dystrophy on chromosome 19q13.1. TULP1 and TULP2, which are expressed in the retina, make excellent candidates for these ocular diseases as a mutation within the tub gene is known to lead to early progressive retinal degeneration.

Down-regulation of murine susceptibility to cerebral malaria by inoculation with third-stage larvae of the filarial nematode Brugia pahangi

In areas where malaria is endemic, helminthic infections, caused by intestinal or filarial parasites, commonly coexist with malaria in the same individual. This study investigates the course of Plasmodium berghei malaria infection in CBA/J mice inoculated with irradiated attenuated 3rd-stage larvae (L3) of Brugia pahangi. Peripheral eosinophil counts, serum IgE levels and cytokine production revealed that the filarial antigen induced T-helper type 2 (Th2) cell predominance in these mice, which protected them against the development of cerebral malaria. These mice significantly prolonged their survival, compared with the control mice after P. berghei infection. All of the mice not inoculated with irradiated L3 died within 12 days with acute neurological manifestations unrelated to the level of parasitaemia after infection of P. berghei. Conversely, most of the inoculated mice lived more than 3 weeks following infection with P. berghei, dying in the fourth week of severe anaemia and overwhelming parasitaemia. This suggests that Th2-dominant responses lead to the down-regulation of susceptibility to murine cerebral malaria.