The critical role of DNA in the equilibrium between OmpR and phosphorylated OmpR mediated by EnvZ in Escherichia coli

Escherichia coli modulates its porin expression through a histidine kinase, EnvZ, and its cognate response regulator, OmpR. EnvZ is a bifunctional enzyme that possesses both OmpR kinase and phosphorylated OmpR (OmpR-P) phosphatase activities and thus controls the cellular level of OmpR-P. In an in vitro-assay system, the addition of OmpR to the reaction mixture consisting of the cytoplasmic domain of EnvZ (EnvZc) and ATP produces a barely detectable amount of OmpR-P because of the dual activities of EnvZ. Here we report that DNA fragments containing the upstream promoter regions of the porin genes (ompF and ompC) can shift the equilibrium between OmpR and OmpR-P dramatically toward OmpR-P. Among the four reactions occurring in the mixture, only the EnvZ phosphatase activity was inhibited severely by the specific DNA, in contrast to the previous report by Kenney and her associates that DNA stimulates OmpR phosphorylation by EnvZ [Ames, S. K., Frankema, N. & Kenney, L. J. (1999) Proc. Natl. Acad. Sci. USA 96, 11792-11797]. The autophosphorylation of EnvZc and the phosphotransfer from phosphorylated EnvZc to OmpR were not affected by DNA, whereas the autodephosphorylation of OmpR-P was inhibited slightly. We propose that the apparent inhibitory effect of DNA on the EnvZ phosphatase function is caused by sequestrating OmpR-P from the reaction as a result of OmpR-P binding to DNA.

Staining intensity of individual osteons correlated with elastic properties and degrees of mineralization

Surface staining is widely used for histological studies involving undecalcified thick bone sections. Individual osteons, particularly newly formed ones stained with toluidine blue (TB), show various color intensities. We studied the correlations between TB color intensity and the differences in stiffness and degree of mineralization of individual osteons in undecalcified histological sections of goat tibial diaphysis, measured by scanning acoustic microscopy (SAM) and contact microradiography (CMR), respectively. Results showed that all three measurements correlated significantly with each other (r = 0.567 - 0.786; all P < or = 0.01). The TB surface staining intensity of individual osteons correlated better with the reflection coefficient (stiffness index) measured by SAM (r = 0.713) than with the aluminum step-wedge equivalent thickness measured on CMR micrographs (r = 0.567). The aluminum step-wedge equivalent thickness of individual osteons on CMR correlated slightly better with the SAM reflection coefficient (r = 0.786) than with the TB surface staining intensity (r = 0.713). The results of this study suggest that TB surface staining may be used as a simple method for indicating differences in stiffness and degree of mineralization in individual osteons in comparative histological studies.

A clinical investigation on garlicin injectio for treatment of unstable angina pectoris and its actions on plasma endothelin and blood sugar levels

To investigate the therapeutic effects and mechanisms of garlicin for treatment of unstable angina pectoris (UAP), garlicin injectio was intravenously dripped 60 mg/day in 34 cases for 10 days. Nitroglycerine was used in 21 cases of the control group. The results showed that the total effective rates in improving symptoms and electrocardiogram after garlicin treatment were respectively 82% and 62%, and that the plasma endothelin and blood sugar levels were markedly lowered in cases with hyperglycemia.

DNA/dendrimer complexes mediate gene transfer into murine cardiac transplants ex vivo

Starburst polyamidoamine dendrimers are synthetic polymers with unique structural and physical characteristics suitable for DNA gene transfer. Our previous studies demonstrated that Starburst dendrimers augment plasmid-mediated gene transfer efficiency in a nonvascularized, cardiac transplantation model. In this study, the fifth generation of ethylenediamine core dendrimer was investigated for its ability to enhance gene transfer and expression in a clinically relevant murine vascularized heart transplantation model. The plasmid pMP6A-beta-gal, encoding beta-galactosidase (beta-Gal), was incubated with dendrimers to form complexes. The complexes were perfused via the coronary arteries during donor graft harvesting, and reporter gene expression was determined by quantitative evaluation of X-Gal staining. The grafts infused with pMP6A-beta-gal/dendrimer complexes showed beta-Gal expression in myocytes from 7 to 14 days. A number of variables for transfer of the DNA/dendrimer complexes were tested, including DNA:dendrimer charge ratios, concentrations of DNA and dendrimer, preservation solutions, ischemic time, and enhancement of vascular permeability by serotonin, papaverine, and VEGF administration. The results showed that DNA/dendrimer complexes containing 20 microg of DNA and 260 microg of dendrimer (1:20 charge ratio) in a total volume of 200 microl resulted in highest gene expression in the grafts. The results also showed that prolonged incubation (cold ischemic time) to 2 h and pretreatment with serotonin further enhanced gene expression.

[Detection of Mycoplasma genitalium in throat by nested polymerase chain reaction and analysis of DNA sequencing in pediatric patients with acute upper respiratory tract infections]

OBJECTIVE

To explore the relation between Mycoplasma genitalium (Mg) and acute upper respiratory tract infection in pediatric patients by using nested polymerase chain reaction(nPCR) and analysis of DNA sequencing techniques.

METHODS

The specimens of throat swab were obtained in 62 acute upper respiratory tract infections children and 80 health children. The two kinds of Mg species-specific, in which the sequences of I-III and V-VII variable regions of Mg 16Sr RNA gene were detected by using nPCR technique. DNA sequences of positive product were detected and analysed.

RESULTS

The Positive rate of health children is 5% (4/80), while the acute upper respiratory tract infection children is 21% (13/62). The difference is significant (P < 0.001). The DNA sequences of positive product shows that: there are two point mutation(T-->C) in the sequences of V-VII variable regions of throat swab of one pediatric patient, other sequences are same as those Mg type strain(G-37T).

CONCLUSIONS

Acute upper respiratory tract infection of pediatric patients have relation with Mg. There are Mg mutant strain in China.

Removal of the lateral or medial third of patellar tendon alters the patellofemoral contact pressure and area: an in vitro experimental study in dogs

OBJECTIVES

To compare patellofemoral contact pressure and areas after immediate removal of the lateral, central, or medial third of patellar tendon.

DESIGN

In vitro experiment in 12 dogs.

BACKGROUND

Alteration of the vector sum of the quadriceps muscle contraction after removal of partial patellar tendon might result in changes of patellar tracking in the trochlea.

METHODS

Patellofemoral contact pressure and areas were recorded using Fuji pressure-sensitive film at 45 degrees, 60 degrees, and 90 degrees of knee flexion under an isometric quadriceps force of 100% body weight. The patellofemoral contact imprint from the intact knees were obtained as control, and the lateral (n=4), central (n=4), and medial (n=4) third of the patellar tendon were subsequently removed and the patellofemoral contact imprint was recorded.

RESULTS

The patellofemoral contact area was found to increase with increasing knee flexion angles. No change in patellofemoral contact pressure and areas was found after removal of the central third patellar tendon. However, after removal of either lateral or medial third of patellar tendon, the patellofemoral contact was rotated with increasing knee flexion angles. This was due to the altered vector sum of the quadriceps force, resulting in significantly decreased patellofemoral contact areas and simultaneously a significantly increased contact pressure, characterized with concentration of patellofemoral contact pressure on both lateral and medial facets of the patellofemoral joint.

CONCLUSIONS

The results suggest that removal of the central third of patellar tendon may not alter the patellofemoral contact pressure and areas as compared with removal of either lateral or medial third of patellar tendon that may result in an altered postoperative tracking mechanism of the patellofemoral joint immediately after operation.

RELEVANCE

Findings of this in vitro animal study supports the use of central third of patellar tendon as autograft for anterior cruciate ligament reconstruction. However, further experimental studies are needed to investigate how the postoperative healing of the host patellar tendon will influence the findings obtained from this in vitro study.

Alteration of patellofemoral contact during healing of canine patellar tendon after removal of its central third

Alterations of the patellofemoral (PF) contact pressure and area were assessed using pressure-sensitive film after the removal of the central third of patellar tendon (PT) with healing over time in twelve dogs. The contralateral knee served as control. Histological sections were prepared for descriptive evaluation. No alterations in PT strain, PF contact pressure and area were measured immediately after the removal of the central third of PT compared with that before its removal. Compared with contralateral control, the healing of the donor PF induced a significantly increased PF contact area but not PF contact pressure in the specimens harvested at 6, 12, and 18 months after operation. Increased PF contact area indicated a proximal shift of the PF joint contact during flexion, which was associated with an increased strain of the healing PT under loading. The healing PT became hypertrophic compared with control, but the differences in the cross-sectional area were reduced over time. Histologically, a poorly organized extracellular matrix was observed at 6 months, with a progressive improvement in collagen fiber alignment up to 18 months postoperatively. The results of this study suggest that the removal of the central third of PT does not immediately change PF contact pressure and areas. However, remodeling of the healing tendon may cause an elongated PT, resulting in an increase in PF contact area under a given quadriceps force by knee extension.

Nuclear localization of enzymatically active green fluorescent protein-CTP:phosphocholine cytidylyltransferase alpha fusion protein is independent of cell cycle conditions and cell types

To address the recent controversy about the subcellular localization of CTP:phosphocholine cytidylyltransferase alpha (CTalpha), this study was designed to visualize green fluorescent protein (GFP). CTalpha fusion proteins directly and continuously under different conditions of cell cycling and in various cell lines. The GFP. CTalpha fusion proteins were enzymatically active and capable of rescuing mutant cells with a temperature-sensitive CT. The expressed GFP.CTalpha fusion protein was localized to the nucleus in all cell lines and required the N-terminal nuclear targeting sequence. Serum depletion/replenishment did not cause shuttling of CTalpha between the nucleus and cytoplasm. Moreover, the subcellular localization of CTalpha was examined continuously through all stages of the cell cycle in synchronized cells. No shuttling of CTalpha between the nucleus and cytoplasm was observed at any stage of the cell cycle. Stimulation of cells with oleate had no effect on the localization of CTalpha. The GFP.CTalpha lacking the nuclear targeting sequence stayed exclusively in the cytoplasm. Regardless of their localization, the GFP.CTalpha fusion proteins were equally active for phosphatidylcholine synthesis and mutant rescue. We conclude that the nuclear localization of CTalpha is a biological event independent of cell cycle in most mammalian cells and is unrelated to activation of phosphatidylcholine synthesis.

Effects of basic fibroblast growth factor (bFGF) on early stages of tendon healing: a rat patellar tendon model

We studied the effects of basic fibroblast growth factor (bFGF) on cell proliferation, type III collagen expression, ultimate stress and the pyridinoline content in the early stages of healing in rat patellar tendon. 96 male Sprague Dawley rats were injected with increasing doses of basic fibroblast growth factor (bFGF) at 3 days after a "window defect" was induced in the mid-part of the patellar tendon. They were killed at 7 and 14 days after the injury. A dose-dependent increase in the number of proliferating cells and the level of expression of type III collagen was demonstrated at only 7 days post-injury. On the other hand, we found no effects of bFGF on ultimate stress and the pyridinoline content of healing tendons. Only time significantly affected both strength-associated parameters. We showed that in vivo supplementation with bFGF affected the initial events of healing such as cell proliferation and type III collagen expression.

[Diagnosis and treatment of bile duct tumor thrombus in patients with hepatocellular carcinoma]

OBJECTIVE

Tumor thrombus in the bile duct (BDT) is very rare in patients with hepatocellular carcinoma (HCC). The prognosis of the patients with BDT is very poor. To improve the prognosis, HCC patients with BDT were retrospectively reviewed.

METHODS

Retrospective study was performed in 16 cases of HCC with BDT found in authors' institute from July 1987 to Oct. 1998. Factors affecting prognosis were analyzed.

RESULTS

The occurrence rate of BDT as 0.76% (16/2100). Removal of BDT and HCC was performed in all but one patients. Fourteen patients were followed-up for over 1 year after operation. The 1-year survival and recurrence rate was 71.4% (10/14) and 57.1% (8/14), respectively. Three female patients survived over 4, 6, and 12 years, respectively.

CONCLUSIONS

Early detection and diagnosis, surgical removal of primary tumors and BDT are the key points to prolong the survival time of patients.

An efficient cDNA-AFLP-based strategy for the identification of putative pathogenicity factors from the potato cyst nematode Globodera rostochiensis

A new strategy has been designed to identify putative pathogenicity factors from the dorsal or subventral esophageal glands of the potato cyst nematode Globodera rostochiensis. Three independent criteria were used for selection. First, genes of interest should predominantly be expressed in infective second-stage juveniles, and not, or to a far lesser extent, in younger developmental stages. For this, gene expression profiles from five different developmental stages were generated with cDNA-AFLP (amplified fragment length polymorphism). Secondly, the mRNA corresponding to such a putative pathogenicity factor should predominantly be present in the esophageal glands of pre-parasitic juveniles. This was checked by in situ hybridization. As a third criterion, these proteinaceous factors should be preceded by a signal peptide for secretion. Expression profiles of more than 4,000 genes were generated and three up-regulated, dorsal gland-specific proteins preceded by signal peptide for secretion were identified. No dorsal gland genes have been cloned before from plant-parasitic nematodes. The partial sequence of these three factors, A4, A18, and A41, showed no significant homology to any known gene. Their presence in the dorsal glands of infective juveniles suggests that these proteins could be involved in feeding cell initiation, and not in migration in the plant root or in protection against plant defense responses. Finally, the applicability of this new strategy in other plant-microbe interactions is discussed.

Generalized low areal and volumetric bone mineral density in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) may be associated with generalized low bone mineral status. The bone mineral density (BMD) of 75 girls of 12-14 years of age and diagnosed as having AIS were compared with 94 age-matched female control subjects. Areal BMD (aBMD) of the lumbar spine (L2-L4) and the bilateral proximal femur were measured using-energy X-ray absorptiometry (DEXA), and volumetric BMD (vBMD) of the nondominant distal radius and bilateral distal tibias was measured with peripheral quantitative computer tomography (pQCT). Relevant anthropometric parameters and the severity of the spinal deformity (Cobb's angle) also were evaluated and correlated with the BMD measurements. Results revealed the presence of a generalized lower bone mineral status in AIS patients. Detailed analysis showed that the aBMD and vBMD measured at the bilateral lower extremities were significantly lower in AIS patients when compared with the same in the normal controls. The most significant effect was seen in the trabecular BMD (tBMD) of the distal tibias. Of all the AIS girls, 38% of the aBMD and 36% of the vBMD were below -1 SD of the normal. BMD was found to correlate better with "years since menarche" (YSM) than with chronological age. When the BMD was evaluated for the 3 YSM groups, aBMD of the proximal femur and tBMD of distal tibias were found to be significantly lower in the AIS patients. Neither the aBMD nor the vBMD of AIS patients was found to be associated with the severity of spinal deformity. In addition, anthropometric measurements showed significantly longer arm span and lower extremities in the AIS girls. We concluded that the AIS girls had generalized lower aBMDs and vBMDs.

Phosphatase activity of histidine kinase EnvZ without kinase catalytic domain

Most histidine kinases are bifunctional enzymes having both kinase and phosphatase activities. The cytoplasmic kinase domain of EnvZ, a transmembrane histidine kinase functioning as an osmosensor in Escherichia coli, consists of two distinct functional subdomains: domain A [EnvZc(223-289)] and domain B [EnvZc(290-450)]. NMR studies demonstrated that domain A consists of a four-helix bundle serving as a dimerization and phosphotransfer domain, and domain B functions as the ATP-binding and catalytic domain. Here we demonstrate that domain A by itself has the phosphatase activity both in vitro and in vivo. This phosphatase activity is Mg(2+) dependent but is not activated by ADP, ATP, or adenosine 5'-[beta, gamma-imido]triphosphate (AMPPNP), each of which may serve as a cofactor for the EnvZ phosphatase activity. Domain B showed a small but distinct effect on the domain A phosphatase activity only in the presence of ADP or AMPPNP. However, when domain B was covalently linked to domain A, dramatic cofactor-dependent enhancement of the phosphatase activity was observed. Extending domain A for another 75 residues at the C terminus or 44 residues at the N terminus did not enhance its phosphatase activity. Substitution mutations at His-243, the autophosphorylation site, demonstrate that the His residue plays an essential role in the phosphatase activity. The so-called X-region mutant L288P that is known to specifically abolish the phosphatase activity in EnvZ had no effect on the domain A phosphatase function. We propose that the EnvZ phosphatase activity is regulated by relative positioning of domains A and B, which is controlled by external signals. We also propose that the His-243 residue participates in both kinase and phosphatase reactions.

Peripheral volumetric bone mineral density in pre- and postmenopausal Chinese women in Hong Kong

The aim of this cross-sectional study was to use a newly available precise and multislice pQCT (Densiscan 2000) for establishing reference data of volumetric bone mineral density (vBMD) of the distal radius. vBMD of the nondominant wrist was measured in 118 healthy Hong Kong Chinese women aged 41-60. Anthropometric parameters, menstrual status, and handgrip strength were also measured. Results showed that there was a significant age-related decline in trabecular BMD (tBMD), integral BMD (iBMD), and cortical BMD (cBMD), with correlation coefficients ranging from -0.401 to -0.547 (P < 0.001). The annual decline of vBMD was 2.22%, 1.79%, and 0.88% in tBMD, iBMD, and cBMD, respectively. When subjects were divided into premenopausal and postmenopausal groups, we found an age-related decline in tBMD and iBMD, but not in cBMD in both groups. The vBMD values interpreted in mg/cm3 in premenopausal women were 238.4 +/- 57.2 in tBMD, 604.6 +/- 82.9 in iBMD, 1415.5 +/- 129.9 in cBMD, and declined significantly (all P < 0.001) to 193.7 +/-54.7 in tBMD, 500.0 +/- 90.3 in iBMD, and 1306.7 +/- 153.5 in cBMD in the postmenopausal women. On average, 16.7% of the subjects showed their vBMDs to be below-1 SD and only 1.7% of them lower than -2 SD. Linear regression showed that the annual decline of vBMD was faster in postmenopausal women with 2.42% in tBMD, 1.90% in iBMD, and 0.88% in cBMD compared with 1.91% in tBMD, 0.98% in iBMD, and 0.55% in cBMD in the premenopausal women. After adjustment for age, only the iBMD with dominant trabecular elements showed a significantly accelerated decrease after the onset of menopause (P = 0.008). Weak or no association was found among vBMDs with anthropometric parameters, years since menopause, or handgrip strength. In conclusion, we found a significant age-related decline of vBMDs in Hong Kong Chinese women aged 41-60 years, characterized by the early reduction of metabolically active trabecular bone after entering the fourth decade of life, with an accelerated decline after the onset of menopause.

Mutations in the p53 tumor suppressor gene in tree shrew hepatocellular carcinoma associated with hepatitis B virus infection and intake of aflatoxin B1

Infection with hepadnaviruses and exposure to aflatoxin B1 (AFB1) are considered to be major risk factors in the development of hepatocellular carcinoma (HCC) in humans. A high rate of p53 mutations at codon 249 has been reported in these tumors. The tree shrew (Tupaia belangeri chinensis) is a useful animal model for the development of HCC after human hepatitis B virus (HBV) infection or AFB1 treatment. Therefore, it was of particular interest to determine whether the p53 gene in tree shrew HCCs associated with HBV infection and/or with exposure to AFB1 is affected in the same manner as in human HCCs. We determined the tree shrew p53 wild-type nucleotide sequences by RT-PCR and automatic DNA-sequencing. Tree shrew wild-type p53 sequence showed 91.7 and 93.4% homologies with human p53 nucleotide and amino acids sequences, respectively, while it showed 77.2 and 73.7% homologies in mice. One HCC and normal liver tissue from AFB1 treated and one HCC from AFB1- and HBV-treated tree shrew showed no change in p53 sequences, while three HCCs from AFB1- and HBV-treated tree shrews showed point mutations in p53 sequences. One HCC showed point mutations at codon 275, which is on the DNA-binding domain of p53 gene, which might be a cause of gain-of-function during the development of HCC. As a result, our finding indicates that tree shrews exposed to AFB1 and/or HBV had neither codon 249 mutations nor significant levels of other mutations in the p53 gene, as is the case with humans.

Reduction of aflatoxin B(1) adduct biomarkers by oltipraz in the tree shrew (Tupaia belangeri chinensis)

The risk of liver cancer is greatest in people both infected with hepatitis B virus (HBV) and highly exposed to aflatoxin B(1) (AFB(1)). The tree shrew (Tupaia belangeri chinensis) is a unique species that can be infected with human HBV, is susceptible to AFB(1)-induced liver cancer, and shows a synergistic interaction between HBV and AFB(1) for liver cancer. In this regard, the tree shrew may be useful for evaluating experimental chemoprevention strategies relevant to high-risk human populations as it mirrors the human epidemiology of liver cancer. To begin developing the model for chemoprevention study, two groups of tree shrews were fed 400 microg AFB(1)/kg b.wt. in milk daily for 4 weeks. One week prior to AFB(1) administration, one group also received oltipraz (0.5 mmol/kg, p.o.) daily for 5 weeks. At weekly intervals, 1 ml of blood and a 24-h urine sample were obtained from each animal. Aflatoxin-albumin adducts in serum were determined by a radioimmunological assay and aflatoxin-N(7)-guanine adducts in urine were measured by HPLC. Aflatoxin-albumin adducts increased rapidly in 2 weeks to plateau at 20 pmol/mg protein, and they diminished after cessation of AFB(1) exposure. Oltipraz significantly attenuated the overall burden of aflatoxin-albumin adducts throughout the exposure period with a median reduction of 80%. In a single cross-sectional analysis at the end of AFB(1) dosing, oltipraz treatment decreased urinary aflatoxin-N(7)-guanine by 93%. Collectively, these results indicate that oltipraz reduces AFB(1) risk biomarkers in the tree shrew in a manner similar to that observed in rodents and humans, and establishes a rationale to evaluate cancer chemoprevention by oltipraz in human HBV-infected, AFB(1) exposed tree shrews.

[Influence of monkshood root-peony root combination on inflamation-induced agents and free radicals]

OBJECTIVE

To find out the effect of monkshood root and peony root on inflammation-induced agents and free radicals when used separately and in combination.

METHOD

Two drugs were made into decoctions separately and in combination, i.p., qd, for 7 d, red blood cell SOD and serum LPO were analysed and the anti-inflammatory actions were observed.

RESULTS

In an experimental rat model with inflamed paw edema induced by carrageenin or formaldehyde and in a mouse model with ear swelling induced by xylene, the anti-inflammatory effect appeared stronger when the two drugs were used in combination, especially in comparison with the use of monkshood root alone. The exudation of blood capillaries and the contents of inflammation medium PGE2 were lowered; The activity of SOD extracted from rat or mouse red blood cells was enhanced, and the serum LPO, which was high in level when monkshood root was used alone, could be declined when the two drugs were used in combination.

CONCLUSION

The drug combination is more effective in inhibiting inflammation and scavenging free radicals.

Differential diagnosis between hepatic focal nodular hyperplasia and hepatocellular carcinoma with negative alhpa-fetoprotein

OBJECTIVE

To study the differential diagnosis between hepatic focal nodular hyperplasia (FNH) and hepatocellular carcinoma (HCC) with negative alpha-feto protein.

METHODS

To analyse retrospectively the clinical and imaging materials of 18 patients with FNH and 254 patients with AFP negative HCC proven by operation and pathology during March 1996 to March 1999 in our institute.

RESULTS

Patients with FNH were largely younger (66.7% under 40 years), discovered accidentally (66.7%), and without hepatitis background (83.3%). Majority of them had a normal liver function (72.0%). A big central artery was found in the lesion with high velocity and low resistant index in 71.4% of patients by color Doppler ultrasound. CT scan showed transient immediate enhancement in 85.7% of patients after bolus injection, being homogeneous (53.3%) and isodensity (73.3%) in the portal vein phase. MR imaging demonstrated early vigorous enhancement (83.3%) and homogenous (66.7%) lesion. In contrast, patients with AFP negative HCC were generally older (85.8% over 40 years), with symptoms (74.0%). A color flow with high velocity and high resistant index was found by color Doppler ultrasound. CT scan showed early heterogenous enhancement (96.6%) after bolus injection and being hypodensity in portal vein phase. MR imaging indicated early heterogeneous enhancement (91.7%).

CONCLUSION

FNH shows some typical clinical and imaging features. Therefore, it is feasible to be differentiated from HCC with negative AFP in some of the patients.

Transforming growth factor-beta1 gene transfer ameliorates acute lung allograft rejection

BACKGROUND

The aim of the current work was to study the feasibility of functional gene transfer using the gene encoding for transforming growth factor-beta1, a known immunosuppressive cytokine, on rat lung allograft function in the setting of acute rejection.

METHODS

The rat left lung transplant technique was used in all experiments, with Brown Norway donor rats and Fischer recipient rats. After harvest, left lungs were transfected ex vivo with either sense or antisense transforming growth factor-beta1 constructs complexed to cationic lipids, then implanted into recipients. On postoperative days 2, 5, and 7, animals were put to death, arterial oxygenation measured, and acute rejection graded histologically.

RESULTS

On postoperative day 2, there were no differences in acute rejection or lung function between animals treated with transforming growth factor-beta1 and control animals. On postoperative day 5, oxygenation was significantly improved in grafts transfected with the transforming growth factor-beta1 sense construct compared with antisense controls (arterial oxygen tension = 411 +/- 198 vs 103 +/- 85 mm Hg, respectively; P =.002). Acute rejection scores from lung allografts were also significantly improved, corresponding to decreases in both vascular and airway rejection (vascular rejection scores: 2.0 +/- 0. 5 vs 2.8 +/- 0.6; P =.04; airway rejection scores: 1.3 +/- 0.7 vs 2. 3 +/- 0.8, respectively; P =.02). The amelioration of acute rejection was temporary and decreased by postoperative day 7.

CONCLUSIONS

The feasibility of using gene transfer techniques to introduce novel functional genes in the setting of lung transplantation is demonstrated. In this model of rat lung allograft rejection, gene transfer of transforming growth factor-beta1 resulted in temporary but significant improvements in lung allograft function and acute rejection pathology.

A monomeric histidine kinase derived from EnvZ, an Escherichia coli osmosensor

Histidine kinases function as dimers. The kinase domain of the osmosensing histidine kinase EnvZ of Escherichia coli consists of two domains: domain A (67 residues) responsible for histidine phosphotransfer and dimerization, and domain B (161 residues) responsible for the catalytic and ATP-binding function. The individual structures of these two domains have been recently solved by NMR spectroscopy. Here, we demonstrate that an enzymatically functional monomeric histidine kinase can be constructed by fusing in tandem two domains A and one domain B to produce a single polypeptide (A-A-B). We show that this protein, EnvZc[AAB], is soluble and exists as a stable monomer. The autophosphorylation and OmpR kinase activities of the monomeric EnvZc[AAB] are similar to that of the wild-type EnvZ, while OmpR-binding and phosphatase functions are reduced. V8 protease digestion and mutational analyses indicate that His-243 of only the amino proximal domain A is phosphorylated. Based on these results, molecular models are proposed for the structures of EnvZc[AAB] and the kinase domain of EnvZ. The present results demonstrate for the first time the construction of a functional, monomeric histidine kinase, further structural studies of which may provide important insights into the structure-function relationships of histidine kinases.

[Effect of chuanwu and baishao used separately or in combination on adjuvant arthritis in rats]

OBJECTIVE

To study the effect of Chuanwu(Aconitum carmichaeli) and Baishao(Paeonia lactiflora) used separately or in combination on the adjuvant arthritis in rats.

METHOD

Chuanwu-Baishao decoctions of different proportions were orally administered to three different rat models with adjuvant arthritis to observe the preventing and curing actions on the primary and secondary adjuvant arthritis in rats.

RESULT

The curing action on the primary adjuvant arthritis appeared the same whether the two ingredients were used separately or in combination, while on the secondary adjuvant arthritis the combination, produced significant preventing effect. Chuanwu was proved weaker in action when used alone Chuanwu and Baishao were very efficacious in curing adjuvant arthritics when used in combination other than separately.

CONCLUSION

In preventing and curing the secondary adjuvant arthritis in rats Chuanwu and Baishao work better in combination.

A histomorphometric observation of flows in cortical bone under dynamic loading

Ferritin was used as a histological marker for interstitial fluid flows in four goats. Two transcortical pins were inserted into each tibia mediolaterally-one at the proximal side and one at the distal side of the diaphysis. For the experimental limb, dynamic loading was applied to the pins on the lateral side. The contralateral limb was used as control. Ferritin was injected into the nutrient arteries feeding the two tibiae. The goat was then euthanized immediately. Undecalcified slides of the tibial cortical bone from both the experimental and the control limbs were studied histologically. Percentages of Haversian systems marked with ferritin halos and the average radial distance of ferritin transudation away from the Haversian canals were assessed. Results for the medial and lateral sides of both the experimental and control tibiae were reported. Significant differences in the ferritin transudation distance were found between the experimental and the control tibia (P < 0.005) and between the medial and the lateral sectors (P < 0.05). The approach documented in this paper could be used to address systematically how external loading might affect the transport phenomena in cortical bone.

[Experimental study of analgesic effect of combined Radix Aconiti and Radix Stephaniae Tetrandrae]

OBJECTIVE

To explore the changes of analgesic effect of combined Radix Aconiti (RA) and Radix Stephaniae Tetrandrae (RST).

METHODS

Randomly divide the rabbits and mice into following groups: the blank control group, the positive control group, the RA group, the RST group, the combined RA:RST(1:1) group, the combined RA:RST(1:2) group. Then, using chemical, heat and electrical stimuli, four kinds of pain models were produced, which were to observe the changes of pain threshold of mice before and after using combined RA and RST therapy.

RESULTS

Remarkable analgesic effect was obtained in the positive control group and all the groups treated with these two herbs within 3 hours (P < 0.01), and the effect was more obvious in the combined RA-RST groups and the RA group. The analgesic effect of the positive control group, the RST and the RA group weakened gradually 3 hours later, and at the 24th hour, the effect disappeared in the positive control group and the RST group but it is still remarkable in the combined RA-RST group, which has a significant difference from the positive control group and the groups treated with one single herb (RA or RST).

CONCLUSION

The analgesic effect of the combined RA-RST is superior to the RA and the RST used alone.

Effects of spaceflight and thyroid deficiency on rat hindlimb development. II. Expression of MHC isoforms

Both slow-twitch and fast-twitch muscles are undifferentiated after birth as to their contractile protein phenotype. Thus we examined the separate and combined effects of spaceflight (SF) and thyroid deficiency (TD) on myosin heavy chain (MHC) gene expression (protein and mRNA) in muscles of neonatal rats (7 and 14 days of age at launch) exposed to SF for 16 days. Spaceflight markedly reduced expression of the slow, type I MHC gene by approximately 55%, whereas it augmented expression of the fast IIx and IIb MHCs in antigravity skeletal muscles. In fast muscles, SF caused subtle increases in the fast IIb MHC relative to the other adult MHCs. In contrast, TD prevented the normal expression of the fast MHC phenotype, particularly the IIb MHC, whereas TD maintained expression of the embryonic/neonatal MHC isoforms; this response occurred independently of gravity. Collectively, these results suggest that normal expression of the type I MHC gene requires signals associated with weight-bearing activity, whereas normal expression of the IIb MHC requires an intact thyroid state acting independently of the weight-bearing activities typically encountered during neonatal development of laboratory rodents. Finally, MHC expression in developing muscles is chiefly regulated by pretranslational processes based on the tight relationship between the MHC protein and mRNA data.

Variation in bone mineral density of the sacrum in young adults and its significance for sacral fixation

STUDY DESIGN

Bone mineral density variations throughout the sacrum were measured and correlated with sacral screw insertion torque.

OBJECTIVE

To quantify bone mineral density variations within the S1 body and ala of young human specimens, especially along the pathways of sacral screws, and to examine the relation between sacral screw fixation and bone mineral density.

SUMMARY OF BACKGROUND DATA

Vertebral bone quality is an essential factor in anterior or posterior screw fixation of the spine. Several studies have been conducted regarding bone mineral density variations in the cervical and thoracolumbar spine. However, such variations in bone mineral density in the sacrum have not been well documented.

METHODS

The bone mineral density of 13 sacral specimens from young male cadavers (mean age, 31 years) was measured using highly accurate quantitative computed tomography. Variations in bone mineral density were measured in five transverse layers and seven vertical columns within the S1 body, and in four transverse layers and six vertical columns within the ala. The sacral screw insertion torque was measured (unicortical and bicortical), and the correlation with bone mineral density was calculated.

RESULTS

The mean bone mineral density of the S1 body was 381.9 +/- 59 mg/cm3, which was 31.9% higher than that of the sacral ala (mean, 296.9 +/- 86 mg/cm3) (P < 0.05). Bone mineral density of the superior sacral endplate was higher than that of any other transverse layer. Columns near the lateral posterior and lateral anterior of the S1 body had the highest bone mineral density. In the ala, bone mineral density values of the internal columns (pedicle) were the highest. Screw insertion torque for bicortical purchase along the S1 pedicle correlated well with the bone mineral density of the S1 body (r = 0.67, P < 0.05).

CONCLUSION

This study quantified the volumetric bone mineral density variations within the S1 body and ala, and a significant linear correlation between the screw insertion torque and bone mineral density was found. Optimal sacral screw insertion pathways were also outlined based on bone mineral density values.