Ubiquitin-dependent pathway is up-regulated in differentiating lens cells

The mammalian eye lens is composed of two distinct types of cells, epithelial cells and fiber cells. The fiber cells are generated throughout life via continuous differentiation of epithelial cells. Differentiation of lens cells involves dramatic changes in cellular components including altered activity of the ubiquitin dependent pathway. The concentration of high mass ubiquitin conjugates in the mitotically active-, differentiating-equatorial epithelial cells was 5-10 fold higher than that observed in mitotically quiescent, non-differentiated, central epithelial cells, even though there was a significant dilution of non-crystallin proteins due to an increase in level of crystallins in the differentiating cells. Similar observations were made when differentiation was modeled by exposure of lens epithelial explants to bFGF in culture. Activities of ubiquitin-activating enzyme (E1) and ubiquitin-conjugating enzymes (E2s) in the differentiating equatorial epithelial cells were also up to 100% higher than those noted in non-differentiated central epithelial cells and E1 appears to be rate controlling for ubiquitinylation. Consistent with the higher concentrations of high mass ubiquitin conjugates, there was a trend of enhanced ability to execute ATP-dependent protein degradation in the differentiating equatorial epithelial cells as compared with degradation in the non-differentiated central epithelial cells. These data indicate that the ubiquitin dependent pathway is up-regulated during differentiation of lens cells. In the differentiated fibers, the concentration of high mass ubiquitin conjugates and relative activities of E1 and E2s were 50% lower than in the non-differentiated central epithelial cells. In comparison, the concentration of the 110 kDa E1 was unchanged in differentiated fibers. However, if the factor of dilution by the significant increase in the level of crystallins was taken into account, the level or activities of the components of ubiquitin pathway in the differentiated cells was higher than the level noted in non-differentiated cells. These data indicate that, as compared with other non-crystallin proteins, there is differential stabilization and/or synthesis of the 110 kDa E1 and some other components of the ubiquitin dependent pathway in differentiated fibers.

Genetic factors influence cataract formation in alpha 3 connexin knockout mice

Connexin alpha 3 (Cx46 or Gja3) gene targeted null mice developed lens nuclear cataracts shortly after birth. A large variance in the cataracts was observed in alpha 3 null sibs on a mixed 129SvJae X C57BL/6J F3 background. This suggested that the genetic background might influence the cataract phenotype. Therefore, we placed the alpha 3 null mutation into a 129SvJae background, and also backcrossed the mutation for six generations into 129SvJ and C57BL/6J backgrounds. While alpha 3 nulls on the two 129 backgrounds contained severe cataracts associated with gamma crystallin cleavage, alpha 3 nulls on the C57B16 background had far milder cataracts with no detectable gamma crystallin cleavage. These findings suggest that a genetic modifier exists that influences gamma crystallin stability, and that gamma crystallin breakdown is associated with severe nuclear cataracts.

Gap junctional coupling in lenses lacking alpha3 connexin

Fiber cells of the lens are interconnected by an extensive network of gap junctions containing alpha3 (Cx46) and alpha8 (Cx50) connexins. A specific role for these connexins in lens homeostasis is not known. To determine the contribution of these connexins to lens function, we used impedance techniques to study cell-to-cell coupling in lenses from homozygous alpha3 knockout (-/-), heterozygous (+/-), and wild-type (+/+) mice. Western blots and immunofluorescence data indicated that alpha8 remained at similar levels in the three classes of lenses, whereas alpha3 was approximately 50% of the normal level in the +/- lenses, and it was absent from the -/- lenses. Moreover, the data from +/+ lenses suggest that a cleavage of connexins occurs abruptly between the peripheral shell of differentiating fibers (DF) and the inner core of mature fibers (MF). The appearance of the cleaved connexins was correlated to a change in the coupling conductance. In -/- lenses the coupling conductance of MF was zero, and these fibers were depolarized by about 30 mV from normal (approximately -65 mV). The DF remained coupled, but the conductance was reduced to 30-35% of normal. However, the gap junctions in the DF of alpha3 -/- lenses remained sensitive to pH. We conclude that alpha3 connexin is necessary for the coupling of central fibers to peripheral cells, and that this coupling is essential for fiber cell homeostasis because uncoupled MF depolarize and subsequently become opaque.

Calorie restriction, stress and the ubiquitin-dependent pathway in mouse livers

Calorie restriction (R) is the only known method to delay the aging process and extend mean and maximal lifespan in rodents. R has been shown to delay the age-related accumulation of damaged proteins and to protect organisms from various stresses which can produce damaged proteins. Such stresses include irradiation, heat shock, and oxidative stress. The ubiquitin- and ATP-dependent proteolytic pathway (UPP) has been associated with the degradation of abnormal and/or damaged proteins. We examined the effect of diet and oxidative stress on activities of the UPP in supernatants from livers taken from 23-month-old Emory mice which had been exposed to an in-vivo injection of paraquat. Paraquat induces oxidative stress by generating superoxide radicals. In livers from non-stressed animals, steady-state levels of endogenous ubiquitin conjugates, de novo conjugate formation, and E1 and E2 activities were significantly lower in R animals than in control (C) animals. However, after exposure to paraquat, levels of endogenous ubiquitin conjugates were significantly higher in R versus C animals, and de novo conjugate formation and E1 and E2 activities in R animals rose to levels which were indistinguishable from levels of these activities noted in C animals. R was associated with an increased ability to degrade beta-lactoglobulin by the UPP after an oxidative stress was imposed. Ability to degrade beta-lactoglobulin by the C or R livers in non-stressed animals was not significantly different. Taken together, these data indicate that oxidative stress in R animals is associated with enhanced levels of ubiquitin conjugates and that this enhancement may be due to an increase in UPP activity. These data also indicate that the ability to form ubiquitin conjugates and the UPP system does not change with oxidative stress in C animals. The latter is consistent with prior reports that suggests that older C animals may already be in a state of enhanced oxidative stress and that activities of the UPP provide a sensitive indicator of levels of cellular redox status.

[An analysis of curative effect of activator in treating Class II division 1 malocclusion]

OBJECTIVE

To analyze the results of class II division 1 malocclusion treated by activator.

METHODS

Sixteen growing patients, who were diagnosed as class II division 1 malocclusion, were evaluated by McNamara analysis.

RESULTS

The activator affects the growth of mandible positively and inhibits the growth of the maxilla.

CONCLUSION

The activator can treat class II division 1 malocclusion effectively, which can be perceived by McNamara analysis directly.

[An ideal imaging quality can be obtained from the evenly scattering x-ray density]

Since X-ray image quality was evaluated by the self-delivering function, the limitations in the application of fixative focus X-ray tube seem more outstanding. How to improve the quality of the x-ray image has been one of the focus problems in the field of the x-ray diagnosis. If we use the x-ray tube of the evenly scattering x-ray density as the radio source, we can get the ideal images.

HIV-1 envelope gp120 inhibits the monocyte response to chemokines through CD4 signal-dependent chemokine receptor down-regulation

Since HIV-1 infection results in severe immunosuppression, and the envelope protein gp120 has been reported to interact with some of the chemokine receptors on human T lymphocytes, we postulated that gp120 may also affect monocyte activation by a variety of chemokines. This study shows that human peripheral blood monocytes when preincubated with gp120 either purified from laboratory-adapted strains or as recombinant proteins exhibited markedly reduced binding, calcium mobilization, and chemotactic response to chemokines. The gp-120-pretreated monocytes also showed a decreased response to FMLP. This broad inhibition of monocyte activation by chemoattractants required interaction of gp120 with CD4, since the effect of gp120 was only observed in CD4+ monocytes and in HEK 293 cells only if cotransfected with both chemokine receptors and an intact CD4, but not a CD4 lacking its cytoplasmic domain. Anti-CD4 mAbs mimicked the effect of gp120, and both anti-CD4 Ab and gp120 caused internalization of CXCR4 in HEK 293 cells provided they also expressed CD4. Staurosporine blocked the inhibitory effect of gp120 on monocytes, suggesting that cellular signaling was required for gp120 to inhibit the response of CD4+ cells to chemoattractants. Our study demonstrates a broad suppressive effect of gp120 on monocyte activation by chemoattractants through the down-regulation of cell surface receptors. Thus, gp120 may be used by HIV-1 to disarm the monocyte response to inflammatory stimulation.

[Epidemiological features of sexually transmitted diseases among children below age 15 at the National STD Surveillance sites]

In order to understand the trends and epidemiological characteristics of sexually transmitted diseases among children below the age of 15 at national STD surveillance sites which will lead to the development of strategies on prevention and control, STD surveillance at selected national sites had been consecutively monitored during the period of 1987-1996 with data collected and analyzed. The epidemiological characteristics of STD among children below age 15 were found as follows: (1) Incidence rates of STD in children appeared to be ascending yearly, from 0.51/100,000 in 1987 to 8.62/100,000 in 1996. (2) Gonorrhea was the most frequently seen sexually transmitted disease among children, constituting 85.58% of the kinds of STDs on average. However, the proportion of gonorrhea cases in children is declining with the increase of NGU and syphilis. (3) Incidence rates among girls were consistently higher than the rates for boys, with a sex ratio of 2.35:1. (4) Incidence rate in group--0 was 44.68 per 100,000 population in 1996, much higher than the rates in other groups of children. (5) Incidence rates among children in both urban and minority areas were higher than the rates in rural area. The STD situation in children at the national STD surveillance sites has become crucial which calls for more attention.

The effects of aging and calorie restriction on plasma nutrient levels in male and female Emory mice

We examined the effect of diet, age (4.5, 13 and 23 months), and sex on plasma levels of retinol, tocopherol, ascorbate, cholesterol, glucose and glycohemoglobin in male and female Emory mice which were fed control (C) and 50% calorie restricted (R) diets. Results showed that C fed animals tended to have higher levels of plasma ascorbate (50-71%), cholesterol (23-71%), glucose (38-81%) and glycohemoglobin (50%). However, these diet differences varied with the age and sex of the animals. Plasma retinol levels were lower only in R males vs. C males (50%). Novel sex-related differences in levels of plasma retinol (2-fold higher in C male mice than in C or R female mice) are described. Aging was associated with trends towards lower levels of plasma ascorbate (14-25%), glucose (34-36%) and glycohemoglobin (47-57%) from 4.5 to 23 months of age. However, these age differences depended upon the diet and sex of the animals. These data suggest that lower plasma levels of glucose, glycosylated hemoglobin and cholesterol may be causally related to the life extension noted in R animals since elevated levels of these moieties have been related to aging. Since oxidative stress is thought to be causally related to aging it appears unlikely that retinol, tocopherol and ascorbate are causally related to R-induced life-extension.

[A methodological study of frequency domain analysis on heart rate variability and RT interval variability]

Recently, heart rate variability (HRV) as a non-invasive measure for assessing the balance of autonomic nervous system has drawn more attentions and HRV analysis has become a focus of the ECG signal processing. QT interval represents the ventricular repolarization duration. QTV might reflect the balance of autonomic nervous system in other way. QTV analysis might complement HRV analysis. Because of the difficulty in detecting QT interval, RT interval is often used instead of QT interval. HRV and QTV detecting methods have been presented in this paper. After recording 24 h ECG signals, R fiducial marks are detected correctly and ectopic beats are removed. T peaks are detected on the basis of templet matching and correlation. The analysis in frequency domain consists of 24 h 3-dimensional frequency chart, as well as trends of HF/LF and HF, with fast Fourier transform and autoregressive techniques. We acquired ECG signals from subjects under controlled respiration in different frequencies. The results of HRV and RTV spectral analysis have shown that HF peak is modulated at the frequency of controlled respiration, which proves that HF peak is dependent on the vagal activity and our method is correct. The establishment of these methods has provided a basis for further research, and the development of HRV and QTV analysis techniques will be more helpful for early diagnosis, monitoring and prognostic assessment of some diseases.

A study of clinical characteristics and treatment of Mooren's ulcer

OBJECTIVE

To investigate the clinical characteristics and to compare the effects of several therapies of Mooren's corneal ulcer.

METHODS

550 consecutive cases of Mooren's corneal ulcer inpatients were analysed, including the age, sex, laterality of the eye, ulcer location, perforative rate, cure rate of surgeries, recurrent rate, and the effects of conjunctiva excision, lamellar keratoplasty (LKP), LKP and plus cyclosporin A eye drop.

RESULTS

The average age of onset of the corneal ulcer was 48.4 years old, the ratio of the male to the female patients was 1:0.74, the bilateral disease was 30% of the total cases, 31.5% of the bilateral disease occurred in the younger group, and 68.5% of the bilateral ulcer occurred in the older group, ulcers located at the limbus of the palpebral fissure were 70% of the total cases, perforative rate was 13.3%, 43.2% of the perforation occurred in the younger group, and 56.8% of the perforation occurred in the older group, recurrent rate of the post-operation was 25.6%, the cure rate of the first procedure of LKP and plus cyclosporin A eye drop was 73.7%, the final cure rate was 95.6%, and the preservative rate of the corneal anatomical structure of the surgeries was 99.7%.

CONCLUSION

The study primarily provided the clinical characteristics of Mooren's corneal ulcer patients of China. The available data do not support the present concept of the classification of the two clinical types. The bilateral ulcer may be the malignant type of Mooren's ulcer. LKP and plus cyclosporin A eye drop was an effective treatment of Mooren's corneal ulcer.

In vivo radioprotective effects of angiogenic growth factors on the small bowel of C3H mice

This study was undertaken to determine if acidic or basic fibroblast growth factor (FGF1 or FGF2) or vascular endothelial growth factor (VEGF) alters the radiation response of small bowel after total-body irradiation (TBI). Female C3H mice were treated with various doses of angiogenic growth factor administered intravenously 24 h before or 1 h after TBI. Radiation doses ranged from 7 to 18 Gy. End points measured were the number of crypts in three portions of the small bowel, the frequency of apoptosis of crypt cells at various times after TBI, and the LD50/30 (bone marrow syndrome) and LD50/6 (GI syndrome). Fibroblast growth factors alone, without TBI, decreased the number of crypts per circumference significantly. Among the factors tested, FGF2 caused the greatest decline in baseline crypt number. Despite this decrease in the baseline crypt number, after irradiation the number of surviving crypts was greater in animals treated with growth factor. The greatest radioprotection occurred at intermediate doses of growth factor (6 to 18 pg/mouse). Mice treated with FGF1 and FGF2 had crypt survival curves with a slope that was more shallow than that for saline-treated animals, indicating radiation resistance of crypt stem cells in FGF-treated mice. The LD50/6 was increased by approximately 10% for all treatments with angiogenic growth factors, whether given before or after TBI. Apoptosis of crypt cells was maximum at 4 to 8 h after TBI. The cumulative apoptosis was decreased significantly in animals treated with angiogenic growth factors, and the greatest protection against apoptosis was seen in animals treated with FGF2 prior to TBI. All three angiogenic growth factors tested were radioprotective in small bowel whether given 24 h before or 1 h after irradiation. The mechanism of protection is unlikely to involve proliferation of crypt stem cells, but probably does involve prevention of radiation-induced apoptosis or enhanced repair of DNA damage of crypt cells.

[Immunohistochemical studies on wholemounts of the cornea and iris-ciliary body after corneal transplantation]

OBJECTIVE

To study the phenotype of the cells involved in the pathogenesis of allograft rejection after corneal transplantation.

METHODS

Wholemounts of the cornea and iris-ciliary body were isolated and prepared from normal rats and those after penetrating corneal transplantation. Immunohistochemical stainings were carried out on these wholemounts using monoclonal antibodies to CD3 (T cell), CD4 [T-helper (Th) cell], CD8 [T-suppressor (Ts) cell], macrophages, dendritic cells, B lymphocytes, major histocompatibility complex (MHC) class II antigen and transforming growth factor-beta (TGF-beta).

RESULTS

All the cells mentioned above except B lymphocytes were positive and present in a small number in the peripheral cornea and limbus of normal rats. A massive influx of CD3, CD4, CD8 positive cells, macrophages, dendritic cells, MHC class II and TGF-beta positive cells not only into cornea but also into the iris was observed 7 days after allograft corneal transplantation. Whereas no B cell was found in the allograft. Such a cellular response was not found in the rats in which corneal transplantation with autologous cornea was performed.

CONCLUSION

T cells, Th cells, Ts cells, macrophages, dendritic cells, MHC class II positive cells and TGF-beta positive cells are involved in the pathogenesis of corneal allograft transplantation. The involvement of the iris and ciliary body may promote or aggravate the allograft rejection.

Requirements for the adaptor protein role of dihydrolipoyl acetyltransferase in the up-regulated function of the pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase

The dihydrolipoyl acetyltransferase (E2 component) is a 60-mer assembled via its COOH-terminal domain with exterior E1-binding domain and two lipoyl domains (L2 then L1) sequentially connected by mobile linker regions. E2 facilitates markedly enhanced function of the pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase phosphatase (PDP). Human E2 structures were prepared with only one lipoyl domain (L1 or L2) or with alanines substituted at the sites of lipoylation (Lys-46 in L1 or Lys-173 in L2). The L2 domain and its lipoyl group were shown to be essential for markedly enhanced PDP function and were required for greatly up-regulated PDK function. The complete absence of the L1 domain reduced the enhancements of both of these activities but not the maximal effector-stimulated PDK activity through acetylation of L2. With nonlipoylated L2 present, lipoylated L1 supported a lesser enhancement in PDK function with significant stimulation upon acetylation of L1. Prevention of L1 lipoylation in K46AE2 removed this competitive L1 role and enhanced L2-facilitated PDK activity beyond that of native E2 when PDK activity was measured in the absence or in the presence of stimulatory effectors. Thus, the E2-L2 domain has a paramount role in facilitating enhanced PDK and PDP function but inclusion of E2-L1 domain, even in a noninteracting (nonlipoylated) form, contributes to the marked elevation of these activities.

Redox regulation of ubiquitin-conjugating enzymes: mechanistic insights using the thiol-specific oxidant diamide

The ubiquitin-proteasome pathway (UPP) regulates critical cell processes, including the cell cycle, cytokine-induced gene expression, differentiation, and cell death. Recently we demonstrated that this pathway responds to oxidative stress in mammalian cells and proposed that activities of ubiquitin-activating enzyme (E1) and ubiquitin-conjugating enzymes (E2s) are regulated by cellular redox status (i.e., GSSG:GSH ratio). To test this hypothesis, we altered the GSSG:GSH ratio in retinal pigment epithelial cells with the thiol-specific oxidant, diamide, and assessed activities of the UPP. Treatment of cells with diamide resulted in a dose-dependent increase in the GSSG:GSH ratio resulting from loss of GSH and a coincident increase in GSSG. Increases in the GSSG:GSH ratio from 0.02 in untreated cells to > or = 0.5 in diamide-treated cells were accompanied by dose-dependent reductions in the levels of endogenous Ub-protein conjugates, endogenous E1-ubiquitin thiol esters, and de novo ubiquitin-conjugating activity. As determined by the ability to form E1-ubiquitin and E2s-ubiquitin thiol esters, E1 and E2s were both inhibited by elevated GSSG:GSH ratios. Inhibition of E1 was associated with the formation of E1-protein mixed disulfides. Activities of E1 and E2s gradually recovered to preoxidation levels, coincident with gradual recovery of the GSSG:GSH ratio. These data support S-thiolation/dethiolation as a mechanism regulating E1 and E2 activities in response to oxidant insult. Ubiquitin-dependent proteolytic capacity was regulated by the GSSG:GSH ratio in a manner consistent with altered ubiquitin-conjugating activity. However, ubiquitin-independent proteolysis was unaffected by changes in the GSSG:GSH ratio. Potential adaptive and pathological consequences of redox regulation of UPP activities are discussed.

[Clinical diagnosis of Colles fracture combined with dorsal subluxation of radial carpal joints]

OBJECTIVE

To study the criteria for evaluating Colles fracture combined with dorsal radiocarpal subluxation (DRS).

METHOD

Fifty cases of Colles fracture combined with DRS, 100 cases of simple Colles fracture without DRS, and 100 normal wrist joint controls were included. We analysed central point displacement and perpendicular line ratio on the lateral view X-ray. For comminuted and severely displaced fracture, central point displacement (CPD) was not adopted because of difficulties in identifying the central point of the articular surface. Perpendicular line ratio (PLR) was suggested.

RESULT

Prominent difference was seen in the CPDs and the PLRs between the Colles fracture combined with DRS group and the simple Colles fracture and the normal control group (P < 0.01). Prominent relevance between the CPD and the PLR was also found (P < 0.05).

CONCLUSION

Central point displacement and perpendicular line ratio can be regarded as the diagnostic criteria for Colles fracture combined with DRS. PLR is especially valuable when the central point is hard to be identified in very comminuted and severely displaced fractures. DRS is suggested when CPD is more than 2.5 mm and PLR is less than 0.76.

Aging, calorie restriction and ubiquitin-dependent proteolysis in the livers of Emory mice

Calorie restriction (R), the only known method to delay the aging process and extend mean and maximal lifespan, has been shown to delay the age-related decline in protein degradation. There are several proteolytic pathways. The ubiquitin- and ATP-dependent proteolytic pathway (UPP) is frequently associated with degradation of damaged abnormal and/or regulatory proteins. We examined the effect of aging and R on supernatants of livers taken from young (4.5 months) and old (23 months) Emory mice. Aging was associated with increased levels of endogenous ubiquitin conjugates, enhanced ability to form high molecular weight conjugates and ubiquitin activating (E1) and ubiquitin conjugating (E2) activity in the control (C) liver supernatants. The age-related increase in levels of endogenous ubiquitin conjugates in liver appears to be primarily due to increased E1 and E2 activities. R prevented the age-related increase in E1 and E2 activity, and thus prevented the age-related increase in levels of ubiquitin conjugates. In spite of the age-related increase in ubiquitin conjugates, no age-related changes in ubiquitin-dependent proteolytic pathway were observed in the C animals. R was associated with an enhanced ability (130%) to degrade beta-lactoglobulin by the ubiquitin-dependent proteolytic pathway in livers from 4.5-month-old animals relative to age-matched C livers. However, rates of the ubiquitin-dependent degradation of beta-lactoglobulin in the 23-month-old C and R animals were indistinguishable. There were no age- or diet-related differences in the ability to degrade another substrate, oxidized ribonuclease (RNase).

Cytotoxicity of contact lens care solution to human corneal epithelium in vitro

PURPOSE

To investigate the cytotoxicity of soft contact lens multi-purpose care solutions which are now in common use in China.

METHODS

The cell culture method was used. Cytotoxicity was indicated by significant increases in the number of dead cells relative to controls.

RESULTS

Cells were exposed to soft contact lens care solutions for 15 min. They were irregular in shape and variable in size. The intercellular space increased and variable in size. The intercellular space increased and the cells became scrunken. With the time of exposure elongated, damage of cells became more severe.

CONCLUSIONS

Four kinds of soft contact lens multi-purpose care solutions may have harmful effects on the culture of human corneal epithelial cells. Soaked lenses should be rinsed with saline before being placed in the eyes in order to reduce the potential toxicity of contact lens care solutions.

[Effect of keratinocyte growth factor on corneal epithelial wound healing]

OBJECTIVE

To select effective methods for accelerating corneal epithelial wound healing and treating persistent corneal epithelial defect.

METHODS

Exogenous keratinocyte growth factor (KGF, 0.1 ng/ml - 100 ng/ml) was added to cultures of human corneal epithelial cells and DNA synthesis in corneal epithelial cells was measured with [(3)H]-thymidine incorporation and liquid scintillation techniques. The effective concentration of topical application of KGF was calculated and 1 microg/ml KGF was then applied topically to rabbit eyes. Corneal epithelial defect was measured by a digital computer at different times.

RESULTS

KGF at a dosage ranging from 1 ng/ml to 100 ng/ml enhanced cellular proliferation effectively (the rate of cell proliferation 27.66% - 76.73%) and in a dose-dependent manner (r = 0.9233, P < 0.001). Topical application of KGF significantly accelerated corneal wound healing in rabbits (Epithelial healing rate in the KGF-treated group was 1.77 +/- 0.23 mm(2)/h, while in the PBS-treated group it was 1.49 +/- 0.24 mm(2)/h; P < 0.05).

CONCLUSION

The results suggest that exogenous KGF stimulate proliferation of human corneal epithelial cells and accelerate corneal epithelial wound healing in vivo.

Antioxidant enzyme activities in lens, liver and kidney of calorie restricted Emory mice

Dietary calorie restriction extends both mean and maximum life span and retards age-related diseases, including eye lens cataract in Emory mice. The beneficial effects of calorie restriction have been hypothesized to reflect enhanced tissue antioxidant capacity. As a test of this hypothesis, we reared male and female Emory mice on control (C) or 40% calorie-restricted (R) diets. We then determined activities of total superoxide dismutase (T-SOD), Cu/Zn-SOD, Mn-SOD, glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT) in eye lens, liver and kidney of young (4.5 or 6 months), mature (11 or 12 months) and old (22 months) animals. Effects of diet, age and sex were evaluated by multi-factor ANOVA. Only kidney GR activities (mean +/- S.E.M.) were significantly enhanced with the R diet (R, 61 +/- 2 vs. C, 54 +/- 3 U/mg protein; P = 0.03). More frequently, we noted reduced antioxidant enzyme activity in R as compared with C animals, including reduced activities of T-SOD in lens, liver and kidney, Cu/Zn-SOD in liver and kidney, liver Mn-SOD and liver CAT (P < 0.05). Effects of age on antioxidant enzyme activity in C mice included age-dependent decreases in lens and kidney CAT and in liver Mn-SOD. There was also an age-dependent increases in liver and kidney Cu/Zn-SOD and liver GR. None of these age-dependent alterations in antioxidant enzyme function were attenuated in tissues of mice fed the R diet. Values for liver CAT were significantly lower in females than in males (P = 0.05). These results indicate that antioxidant enzyme activities in Emory mouse tissues are influenced by diet, age and sex. However, it is unlikely that increased lifespan and attenuation of cataract (and perhaps other age-dependent debilities), which are associated with the R diet in the Emory mouse, are due to enhanced antioxidant enzyme capabilities.

Disruption of alpha3 connexin gene leads to proteolysis and cataractogenesis in mice

Gap junction channels formed by alpha3 (Cx46) and alpha8 (Cx50) connexin provide pathways for communication between the fiber cells in the normal transparent lens. To determine the specific role of alpha3 connexin in vivo, the alpha3 connexin gene was disrupted in mice. Although the absence of alpha3 connexin had no obvious influence on the early stages of lens formation and the differentiation of lens fibers, mice homozygous for the disrupted alpha3 gene developed nuclear cataracts that were associated with the proteolysis of crystallins. This study establishes the importance of gap junctions in maintaining normal lens transparency by providing a cell-cell signaling pathway or structural component for the proper organization of lens membrane and cytoplasmic proteins.

[The combined procedure of limbal transplantation (LT) and penetrating keratoplasty (PK) for severe ocular obsolete chemical or thermal burns]

PURPOSE

To improve the prognosis of grafts for obsolete ocular chemical or thermal burns.

METHODS

LT + PK or PK were performed in 28 eyes with severe chemical or thermal burns. The effects of the two groups were compared.

RESULTS

In LT + PK group(12 eyes), during 5 to 28 months of follow-up, the results showed improved visual acuity in 9 eyes (75%), maintained stable epithelial adhesion without recurrent erosion or persistent epithelial defect in 11 eyes (91.67%), graft transparent in 9 eyes (75%). Nine eyes (75%) showed prevented neovascularization and conjunctival tissue from growing into graft. Allograft rejection were identified in 4 eyes (33.33%). In routine PK group (16 eyes), during 3 to 22 months of follow-up, the results showed improved visual acuity in 4 eyes (25%), maintained stable epithelial adhesion without recurrent erosion or PCED in 8 eyes (50%), graft transparent in 4 eyes (25%). Four eyes (25%) showed prevented neovascularization and conjunctival tissue from growing into cornea.

CONCLUSIONS

Combined procedure of LT and PK is an effective treatment for severe ocular chemical or thermal burns. It can reduce persistent corneal epithelial defect and prevent neovascularization and conjunctival epithelial from growing into cornea thus maintaining graft transparent and improving visual acuity.

Regulation of ubiquitin-conjugating enzymes by glutathione following oxidative stress

Upon oxidative stress cells show an increase in the oxidized glutathione (GSSG) to reduced glutathione (GSH) ratio with a concomitant decrease in activity of the ubiquitinylation pathway. Because most of the enzymes involved in the attachment of ubiquitin to substrate proteins contain active site sulfhydryls that might be covalently modified (thiolated) upon enhancement of GSSG levels (glutathiolation), it appeared plausible that glutathiolation might alter ubiquitinylation rates upon cellular oxidative stress. This hypothesis was explored using intact retina and retinal pigment epithelial (RPE) cell models. Exposure of intact bovine retina and RPE cells to H2O2 (0.1-1.7 micromol/mg) resulted in a dose-dependent increase in the GSSG:GSH ratio and coincident dose-dependent reductions in the levels of endogenous ubiquitin-activating enzyme (E1)-ubiquitin thiol esters and endogenous protein-ubiquitin conjugates and in the ability to form de novo retinal protein-125I-labeled ubiquitin conjugates. Oxidant-induced decrements in ubiquitin conjugates were associated with 60-80% reductions in E1 and ubiquitin-conjugating enzyme (E2) activities as measured by formation of ubiquitin thiol esters. When GSH levels in RPE cells recovered to preoxidation levels following H2O2 removal, endogenous E1 activity and protein-ubiquitin conjugates were restored. Evidence that S thiolation of E1 and E2 enzymes is the biochemical link between cellular redox state and E1/E2 activities includes: (i) 5-fold increases in levels of immunoprecipitable, dithiothreitol-labile 35S-E1 adducts in metabolically labeled, H2O2-treated, RPE cells; (ii) diminished formation of E1- and E2-125I-labeled ubiquitin thiol esters, oligomerization of E225K, and coincident reductions in protein-125I-labeled ubiquitin conjugates in supernatants from nonstressed retinas upon addition of levels of GSSG equivalent to levels measured in oxidatively stressed retinas; and (iii) partial restoration of E1 and E2 activities and levels of protein-125I-labeled ubiquitin conjugates in supernatants from H2O2-treated retinas when GSSG:GSH ratios were restored to preoxidation levels by the addition of physiological levels of GSH. These data suggest that the cellular redox status modulates protein ubiquitinylation via reversible S thiolation of E1 and E2 enzymes, presumably by glutathione.

[Report of four cases of 22 channel cochlear implantations]

22 channel cochlear implants were implanted in 3 postlinguistical deafened adults and a prelinguistical deafened adolescent. All 4 patients including one with total cochlear ossification and another with congenital cochlear malformation showed significant auditory performance and demonstrated satisfactorily improved speech perception test scores postoperatively.

Activity of ubiquitin-dependent pathway in response to oxidative stress. Ubiquitin-activating enzyme is transiently up-regulated

Relations between the ubiquitin pathway and cellular stress have been noted, but data regarding responses of the ubiquitin pathway to oxidative stress are scanty. This paper documents the response of this pathway to oxidative stress in lens cells. A brief exposure of lens epithelial cells to physiologically relevant levels of H2O2 induces a transient increase in activity of the ubiquitin-dependent pathway. Ubiquitin conjugation activity was maximal and increased 3. 5-9.2-fold over the activity noted in untreated cells by 4 h after removal of H2O2. By 24 h after removal of H2O2, ubiquitin conjugation activity returned to the level noted in untreated cells. In parallel to the changes in ubiquitin conjugation activity, the activity of ubiquitin-activating enzyme (E1), as determined by thiol ester formation, increased 2-6.7-fold during recovery from oxidation. Addition of exogenous E1 resulted in an increase in ubiquitin conjugation activity and in the levels of ubiquitin carrier protein (E2)-ubiquitin thiol esters in both the untreated cells and the H2O2-treated cells. These data suggest that E1 is the rate-limiting enzyme in the ubiquitin conjugation process and that the increases in ubiquitin conjugation activity which are induced upon recovery from oxidation are primarily due to increased E1 activity. The oxidation- and recovery-induced up-regulation of E1 activity is primarily due to post-synthetic events. Substrate availability and up-regulation of E2 activities also appear to be related to the enhancement in ubiquitinylation upon recovery from oxidative stress. The oxidation-induced increases in ubiquitin conjugation activity were associated with an increase in intracellular proteolysis, suggesting that the transient increase in ubiquitinylation noted upon recovery from oxidative stress may play a role in removal of damaged proteins from the cells.

[Unambiguous turbulence measurement method and system using transverse Doppler techniques]

This paper introduces the principle of Doppler ambiguity process and the ambiguity reduction techniques using dual-sample volume. An unambiguous fluid turbulence measurement method using transverse Doppler and dual-sample volume cross-correlation techniques is described. An experimental turbulence detection system is designed. Theoretical and experimental results show that this method can eliminate the Doppler ambiguity spectra produced by transit-time effect, turbulence and velocity gradient in sample volume.

[Carotid cavernous fistula (report of 14 cases)]

Fourteen cases of carotid cavernous fistula (CCF), including 9 cases of traumatic CCF and 5 cases of spontaneous CCF, were treated respectively or in combination with the ligation of the carotid, the isolation of the fistula, following clipping of its upper and lower reaches of the carotid, and endovascular treatment of balloons, steel coils, dry frozen dural pieces or Ivalon grains. It is considered that the detachable balloon endovascular embolization is a choice treatment for CCF.

[Culture of human corneal epithelial cells]

PURPOSE

To select culture technique of human epithelial cells for grafts.

METHODS

Epithelial cells of limbus were collected by improved enzymatic disaggregation or explant technique growth curves and to calculate doubling time. DNA synthesis of cells were measured with 3H-thymidine incorporation and liquid scintillation techniques.

RESULTS

Doubling time of cells which were collected by enzymatic disaggregation and by explant technique were 54.15 +/- 4.28 h and 67.88 +/- 1.96 h (P < 0.01). Cellular DNA synthesis of the former was more active (P < 0.01).

CONCLUSIONS

Epithelial cells which were collected by improved enzymatic disaggregation from limbus include stem cells of corneal epithelium. These cells show more active cellulde proliferation and are fitter for use as grafts.

[Causes and influential factors of spectral broadening in Doppler flow signal]

Signals received are the resultant of the blood flow phasors in CW Doppler system and there are spectral broadening phenomena in it, in other words, frequency of signals corresponding to a moving RBC is not single. A model is presented that enables the detailed effects of spectral broadening to be calculated for a CW Doppler system by using geometric boundary argument. Results are given for the circular geometry.

Monocyte chemotactic protein-2 (MCP-2) uses CCR1 and CCR2B as its functional receptors

Monocyte chemotactic protein (MCP)-2 is a member of the C-C chemokine subfamily, which shares more than 60% sequence homology with MCP-1 and MCP-3 and about 30% homology with macrophage inflammatory protein (MIP)-1alpha, regulated on activation of normal T cell expressed (RANTES), and MIP-1beta. Despite this considerable sequence homology to other C-C chemokines, MCP-2 appears to have unique functional properties in comparison with other C-C chemokines such as MCP-1 and MCP-3. Although evidence obtained from studies on leukocytes suggested that MCP-2 may share the receptors with these C-C chemokines, the actual functional receptors for MCP-2 have not yet been identified. In this study, by using radioiodinated MCP-2, we identified high affinity binding sites for MCP-2 on human peripheral blood monocytes. The MCP-2 binding was competed for by MCP-1 and MCP-3, but less well by MIP-1alpha or RANTES. In experiments using cells transfected with C-C chemokine receptors, 125I-MCP-2 bound to human embryonic kidney 293 cells transfected with CCR1 or CCR2B, known to also bind MIP-1alpha/RANTES and MCP-1, respectively, but both shared by MCP-3. The binding of 125I-MCP-2 to these receptor-transfected cells was displaced completely by chemokines that bind to these receptors. Both CCR1- and CCR2B-transfected 293 cells showed significant migration in response to MCP-2, in addition to responding to other specific chemokines. These results clearly demonstrate that MCP-2, unlike MCP-1, uses both CCR1 as well as CCR2B as its functional receptors, and this accounts for the unique activities of MCP-2.

[Penetrating keratoplasty combined with pupilloplasty]

OBJECTIVE

To investigate the effect of penetrating keratoplasty combined with pupilloplasty.

METHOD

The penetrating keratoplasty combined with pupilloplasty was performed on 48 eyes. They had been followed-up for 6-89 months postoperatively.

RESULTS

The rate of clarity was 79.2%, and the visual acuity of 0.1 or better was restored in 64.6% after an average follow-up of 19.4 months. The pupil was repaired to approximately normal in 89.6%, and the incidence of postoperative complications, anterior synechia and glaucoma, was lowered.

CONCLUSION

The results show that the combined operation can reduce the postoperative complications, improve the prognosis of grafts and vision, and is valuable for the patients with corneal opacity and gappy iris.

Developmental regulation of Zbu1, a DNA-binding member of the SWI2/SNF2 family

The SWI2/SNF2 gene family has been implicated in a wide variety of processes, involving regulation of DNA structure and chromatin configuration, mitotic chromosome segregation, and DNA repair. Here we report the characterization of the Zbu1 gene, also known as HIP116, located on human chromosome band 3q25, which encodes a DNA-binding member of this superfamily. Zbu1 was isolated in this study by its affinity for a site in the myosin light chain 1/3 enhancer. The protein has single-stranded DNA-dependent ATPase activity, includes seven helicase motifs, and a RING finger motif that is shared exclusively by the RAD5, spRAD8, and RAD16 family members. During mouse embryogenesis, Zbu1 transcripts are detected relatively late in fetal development and increase in neonatal stages, whereas the protein accumulates asynchronously in heart, skeletal muscle, and brain. In adult human tissues, alternatively spliced Zbu1 transcripts are ubiquitous with highest expression in these tissues. Gene expression is also dramatically induced in human tumor lines and in Li-Fraumeni fibroblast cultures, suggesting that it is aberrantly regulated in malignant cells. The developmental profile of Zbu1 gene expression and the association of the protein with a tissue-specific transcriptional regulatory element distinguish it from other members of the SWI2/SNF2 family and suggest novel roles for the Zbu1 gene product.

[Effects of a high-pass filter on the Doppler blood flow signal]

A high-pass filter is used to remove the large signals scattered or reflected from stationary and slow moving objects in many clinical CW Doppler units. theoretical results are presented that such a filter will lead to overestimate of the mean velocity of Doppler blood flow. As for different frequency signals, high-pass filter have different amplitudes and phase responses, consequently, nonlinear phase shift is produced. It is proved by computer experiment that nonlinear phase shift caused by high-pass filter hardly has any effects on Doppler flow power spectrum if the high-pass filter does not affect the amplitudes of signals.

[Simultaneous determination of carotenoids and chlorophylls in algae by high performance liquid chromatography]

An isocratic reversed-phase HPLC method for the simultaneous determination of carotenoids and chlorophylls in algae is presented. Both carotenoids and chlorophylls were separated by using a C18 column and a mobile phase consisting of dichloromethane/acetonitrile/methanol/water (22.5:9.5:67.5:0.5). The flow rate was 1.0mL/min. These pigments were detected by a UV-VIS absorbance detector set at 450nm. The average recoveries of these pigments by standard addition method were 99.1% for lutein, 98.5% for alpha-carotene, 99.4% for beta-carotene, 100.6% for chlorophyll a and 99.9% for chlorophyll b. The relative standard deviations of these pigments were 2.4% for lutein, 5.6% for alpha-carotene, 6.0% for beta-carotene, 4.1% for chlorophyll a and 4.0% for chlorophyll b. The calibration curves for these pigments gave good linearity over a wide range of 0-50mg/L (r = 0.9992-0.9999). The retention times were 3.0 min for lutein, 4.7 min for chlorophyll b, 6.3 min for chlorophyll a, 14.1 min for alpha-carotene, and 14.7 min for beta-carotene. Using this method, carotenoids and chlorophylls were determined in Spirulina platensis, Chlorella vulgaris and Haematococcus lacustris. Chlorella vulgaris and Haematococcus lacustris samples were ground in a B. Braun homogenizer. Spirulina platensis sample was smashed by supersonic wave. Acetone was used as extractant.

Identification of previously unrecognized common elements in eukaryotic promoters. A ribosomal RNA gene initiator element for RNA polymerase I

A new ribosomal RNA promoter element with a functional role similar to the RNA polymerase II initiator (Inr) was identified. This sequence, which we dub the ribosomal Inr (rInr) is unusually conserved, even in normally divergent RNA polymerase I promoters. It functions in the recruitment of the fundamental, TATA-binding protein (TBP)-containing transcription factor, TIF-IB. All upstream elements of the exceptionally strong Acanthamoeba castellanii ribosomal RNA core promoter, to within 6 base pairs of the transcription initiation site (tis), can be deleted without loss of specific transcription initiation. Thus, the A. castellanii promoter can function in a manner similar to RNA polymerase II TATA-less promoters. Sequence-specific photo-cross-linking localizes a 96-kDa subunit of TIF-IB and the second largest RNA polymerase I subunit (A133) to the rInr sequence. A185 also photo-cross-links when polymerase is stalled at +7.

Age-related decline in ubiquitin conjugation in response to oxidative stress in the lens

Accumulation of damaged proteins is a major age-related change in lenses of virtually all species and is associated with lens opacification. Proteolytic removal of the damaged proteins may play an important role in maintaining the transparency of the lens. In many tissues, selective removal of abnormal or damaged proteins occurs via a ubiquitin-dependent proteolytic pathway. Ubiquitin, an 8.5 kDa polypeptide, selectively binds to proteins to form ubiquitin-protein conjugates. This ubiquitin-protein conjugate is, in most cases, a signal for protein degradation. In this work, age-related changes in rat lens in the following aspects were detected: (a) levels of the ubiquitin-protein conjugates, (b) some of the enzymes involved in ubiquitin conjugation in rat lenses, and (c) ability to respond to oxidative damage. Endogenous ubiquitin-protein conjugates were detected in epithelium, cortex and nucleus of lenses from young and old rats. The levels of endogenous high molecular weight (HMW) ubiquitin-protein conjugates in each developmental zone of the lenses from young rats were higher than that in the counterparts of lenses from old animals. Peroxide-treatment generally resulted in elevated levels of endogenous HMW ubiquitin-protein conjugates although masses of bulk proteins remain unchanged. The increases in ubiquitin-protein conjugates in the epithelial sections of young and old lenses upon oxidative stress were comparable. In the cortex of young lenses, there was a significant oxidation-related increase in ubiquitin-protein conjugates. There was a similar trend but diminished response in the cortex of old lenses. Nuclear fibers from young lenses also showed an oxidation-induced increase in the level of ubiquitin-protein conjugates. This response was not observed in nuclear fibers of old lenses. The ability to form HMW-ubiquitin conjugates with exogenous 125I-labeled ubiquitin in the lens also increased upon oxidative stress. The extent of the increase in the de-novo ubiquitin conjugating activity upon exposure to oxidation in old lens was much smaller than in young lens. Ubiquitin-activating enzyme (E1), and ubiquitin conjugating enzymes (E2(17k), E2(20k) and E2(25k) were detected by thiol ester assays or Western blot analysis. No significant age-related changes in the levels of E1, E2(17k), E2(20k) and E2(25k) were detected. The activity of E1 and E2(17k) increased upon exposure to H2O2. These data indicate that lens has the ability to increase ubiquitin conjugation activity in response to oxidative stress and this ability is attenuated upon aging. The age-related decrease in the ability to mount a ubiquitin-dependent response upon oxidation may contribute to the accumulation of damaged proteins in the old lenses.

Effects of calorie restriction and aging on the expression of antioxidant enzymes and ubiquitin in the liver of Emory mice

We studied the effect of age and calorie restriction on the expression of genes involved in antioxidant defenses in livers of young (4.5-6 months) and old (22 months) Emory mice fed a control (C) or restricted (R) diet. Specifically examined were catalase (CAT), glutathione peroxidase (Gpx), Cu/Zn and Mn superoxide dismutase (Cu/ZnSOD and MnSOD). As an indicator of oxidative damage to the tissues we measured lipid peroxidation. As indicators of oxidative stress we determined ubiquitin mRNA levels and endogenous high molecular weight (HMW) ubiquitin conjugates. Lower mRNA levels of ubiquitin (P < 0.05), CAT (P < 0.01) and Gpx (P < 0.01) were observed in tissues from young R versus C animals. The old C group had a lower CAT mRNA level (P < 0.0001) compared with young C. In the R group, age did not affect the CAT mRNA levels or Gpx mRNA levels; however, ubiquitin mRNA levels were higher (P < 0.05). No significant changes in Cu/Zn or MnSOD mRNA were observed with age or diet. Cu/ZnSOD protein levels were lower in the young R at 4.5 months (P < 0.05) than young C, and higher in the old R group versus old C (P < 0.05). CAT protein levels were higher in the old C versus old R (P < 0.05). Changes of HMW ubiquitin conjugates with age r diet were not significant. Of the four groups, the old R group showed the highest levels of lipid peroxidation.

A library of organic landscapes on filamentous phage

A billion-clone library of filamentous phage with different surface structures ("landscapes') was generated by fusing random octapeptides to the N-terminus of all 4000 copies of the major coat protein. Such a "landscape library' might include clones exhibiting emergent properties that inhere in the entire surface architecture, not in the peptides by themselves. Because the diverse surface landscapes are displayed on viable phage, they can be surveyed for exceedingly rare functions using microbiological selection methods. Clones with several emergent properties of the sort envisioned were successfully selected, suggesting that landscape libraries have promise as a novel source of nanomaterials with exploitable surface properties.

[Effect of combining EGF with KGF on proliferation of human corneal epithelial cells]

OBJECTIVE

To select effective drugs for enhancing corneal epithelial wound healing and treating persistent corneal epithelial defect.

METHODS

Epidermal growth factor (EGF) and keratinocyte growth factor (KGF) were added to cultures of human corneal epithelial cells and DNA synthesis in corneal epithelial cells were measured with [3H]-thymidine incorporation and liquid scintillation techniques. The cells were counted in a hemocytometer to determine the doubling time.

RESULTS

10 ng/ml EGF, 10 ng/ml KGF enhanced cellular proliferation effectively (P < 0.01). EGF in combination with KGF, the enhancement was more effective (P < 0.05) and reduced the doubling time.

CONCLUSIONS

Our results suggest that exogenous EGF with KGF can stimulate proliferation of human corneal epithelial cells and it may be of potential use clinically for treatment of persistent corneal epithelial

Probing the basis of antibody reactivity with a panel of constrained peptide libraries displayed by filamentous phage

The structural requirements for peptide binding to an antibody may be elucidated by probing it with a variety of peptides having different constraints. To this end, we have constructed and screened a panel of peptide libraries displayed by filamentous bacteriophage. The peptides in most of the libraries have the potential for constraint by fixed Cys residues, which have been placed at different sites within a randomized amino acid sequence of varying length. When taken together, the binding data obtained from screening the panel with a given antibody allow one to determine the types of constraints that promote binding, as well as the residues that are critical for binding. We describe the construction of 11, pVIII-displayed, peptide libraries, whose sizes range from 150 million to 10 billion clones. The libraries were screened with a number of polyclonal and monoclonal antibodies against peptides, proteins and carbohydrates. Cross-reactivity with peptides was always found for antibodies produced against peptides, linear epitopes on folded proteins and, surprisingly, carbohydrates, whereas antibodies against discontinuous epitopes on proteins were found less frequently. The implications of these results are discussed in terms of the structural basis for cross-reactivity with peptides.

Acoustic nonlinearity parameter tomography for biological specimens via measurements of the second harmonics

The acoustic nonlinearity parameter B/A is a new parameter in ultrasound tissue characterization. In this paper, on the basis of a theoretical analysis of finite amplitude ultrasonic wave propagation in fluidlike media, an experimental system for nonlinearity parameter tomography is developed. Using this system, the amplitude of the second harmonic wave cumulated in the propagation path of the primary wave is measured and the finite amplitude insert-substitution method is used in the conventional computer tomography (CT) technique. The filtered convolution algorithm is implemented using the amplitude of the second harmonic as the projection data, then the B/A tomography can be reconstructed. The B/A images for several biological samples are obtained. Besides, the image of porcine pathological liver tissue is studied and is compared with that of porcine normal liver tissue. These results show the potential applications of the nonlinearity parameter B/A in medical diagnosis.

Red-band holographic storage in azo dye sensitized by noncoherent light

Biphoton holographic storage recorded with 633-nm He-Ne beams has been investigated in Methyl Yellowdoped polystyrene film sensitized by weak noncoherent light from a low-pressure Hg lamp. It is demonstrated that the holography in the sample is erasable without fading. The dynamic behavior of the hologram is dependent on the cis-trans isomerization by noncoherent light and 633-nm beams and photoinduced heat.

[Experimental study of Colles' fracture combined with dorsal radio-carpal subluxation]

By cutting different ligaments and the distal end of radius of 20 fresh specimens with radiophotographic records, the author explored the mechanism of formation and traumatic anatomy of Colles' fracture with dorsal radio-carpal subluxation (DRSA). The results of experimental studies indicate that under normal condition, the change of radiolunate angle has some influence on the displacement of central point of lunate (CPL) but does not lead to DRS. The first is the rupture of the dorsal and palmar ligaments of radiocarpal joint and the second is the fracture of distal end of radius with a reversed palmar tilting angle of articular surface of distal radius. To treat the patients of Colles' fracture with DRS the previous palmar tilting angle should be restored to the full, as well as the anatomic reduction. The fixatiion in neutral or light dorsal extension position should be recommended.

Activation of a G protein complex by aggregation of beta-1,4-galactosyltransferase on the surface of sperm

Fertilization is initiated by the species-specific binding of sperm to the extracellular coat of the egg. One sperm receptor for the mouse egg is beta-1,4-galactosyltransferase (GalTase), which binds O-linked oligosaccharides on the egg coat glycoprotein ZP3. ZP3 binding induces acrosomal exocytosis through the activation of a pertussis toxin-sensitive heterotrimeric guanine nucleotide-binding protein (G protein). The cytoplasmic domain of sperm surface GalTase bound to and activated a heterotrimeric G protein complex that contained the Gi alpha subunit. Aggregation of GalTase by multivalent ligands elicited G protein activation. Sperm from transgenic mice that overexpressed GalTase had higher rates of G protein activation than did wild-type sperm, which rendered transgenic sperm hypersensitive to their ZP3 ligand. Thus, the cytoplasmic domain of cell surface GalTase appears to enable it to function as a signal-transducing receptor for extracellular oligosaccharide ligands.

Site-directed photo-cross-linking of rRNA transcription initiation complexes

Site-specific photo-cross-linking of the rRNA committed transcription complex was carried out by using 5-[N-(p-azidobenzoyl)-3-aminoallyl]-dUMP-derivatized promoter DNA. Putative TAFIs of 145, 99, 96, and 91 kDa, as well as TATA-binding protein (TBP), were found to specifically photo-cross-link to different positions along the promoter. These had been identified as potential subunits of the fundamental transcription initiation factor TIF-IB (also known as SL1, factor D, and TFID) from Acanthamoeba castellanii by purification to apparent homogeneity. No other polypeptides attributable to the rRNA architectural transcription factor UBF were identified, suggesting that this protein is not part of the committed complex. Scanning transmission electron microscopy of the complexes was used to estimate the mass of the complex and the contour length of the DNA in the complex. This showed that a single molecule of TIF-IB is in each committed complex and that the DNA is not looped around the protein, as would be expected if UBF were in the complex. A circular permutation analysis of DNA bending resulting from TIF-IB binding revealed a 45 +/- 3.1 degrees (n = 14) bend centered 23 bp upstream of the transcription initiation site. This degree of bending and the position of the bend relative to the site of TBP photo-cross-linking are consistent with earlier data showing that the TBP TATA box-binding domain is not utilized in the assembly of the rRNA committed complex (C. A. Radebaugh, J. L. Mathews, G. K. Geiss, F. Liu, J. Wong, E. Bateman, S. Camier, A. Sentenac, and M. R. Paule, Mol. Cell. Biol. 14:597-605, 1994).

[Cardial myxoma: analysis of cardiopulmonary bypass perfusion in 95 cases]

From 1980 to 1993, 95 patients with cardial myxoma (male 32 and female 63) were treated surgically. The myxoma located on left-atrium in 88 patients, right-atrium in 5, left-ventricle in 1, and pulmonary in 1. All the operations were carried out under cardiopulmonary bypass. After operations, 12 patients had dyspnea and 8 died of pulmonary infection and heart or respiratory failure. The hemoglobin level was 118.02 +/- 16.7 g/L, 72.33 +/- 8.82 g/L, and 105.75 +/- 5.91 g/L respectively for pre-dilution, post-dilution, and post-operation. The patients with cardial myxoma often complicated with anemia (56), hepatic enlargement (36), and history of heart failure (64), and embolism (12). Combined with clinical characteristics mentioned above, the preparation of prime solution and the management of perfusion were discussed.

[The effects of glucocorticoid on rabbit polymorphonuclears during inflammation]

The CD18 expression on rabbit polymorphonuclears (PMNs) and adhesion rate of rabbit PMNs to ICAM-1 coated magnetic beads were determined, and the correlationship was analysed between CD18 expression and adhesion rate. The results showed that glucocorticoid inhibited the rise of CD18 expression on rabbit PMNs caused by tumor necrosis factor (TNF) and that the inhibitory effect reversed when glucocorticoid receptor (GR) was blocked by RU 38486. There was a positive correlationship (r = 0.966) after PMNs were cultured with a range concentration of dexamethasone (Dex). The data indicate that GC inhibits the rise of CD18 expression on rabbit PMNs caused by TNF which is mediated by GR, and plays an important role in inhibition of PMNs adhesion.

[Effects of glucocorticoid on PMN adhesion induced by TNF]

TNF was used as a stimulating factor to study the effects of glucocorticoid (GC) on polymorphonuclear leucocyte (PMN) adhesion. The results showed that tumor necrosis factor (TNF) could increase the PMN adhesion markedly, and Dex could not inhibit the PMN adhesion induced by TNF, but it had a certain effect of prevention. PMN adhesion was increased prominently when Dex and RU 38486 were given after TNF pretreatment.