Synergistic activation of DNA synthesis in astrocytes by fibroblast growth factors and extracellular ATP

The effects of extracellular ATP and polypeptide growth factors on DNA synthesis in primary cultures of rat astrocytes have been examined. It was found that ATP acts synergistically with either acidic or basic fibroblast growth factor to stimulate DNA synthesis. The specificity of this effect was demonstrated by the inability of ATP to potentiate DNA synthesis induced by platelet-derived growth factor or epidermal growth factor. ATP appears to act via P2 purinergic receptors, because (a) it was more effective than adenosine and (b) the synergistic effect was observed with the hydrolysis-resistant P2 agonists, ADP beta S and ATP gamma S. The evidence suggests that extracellular ATP may be an important factor in regulating the extent of gliosis and, as such, may be involved in mechanisms of neural injury and repair.

Enhanced functional preservation of cold-stored rat heart by a nucleoside transport inhibitor

This study investigates the hypothesis that inhibition of nucleoside transport during hypothermic storage elevates tissue adenosine (ADO) content and improves the function of the isolated rat heart. The hearts, flushed with a cardioplegic solution containing varying concentrations (0-100 nM) of a nucleoside transport inhibitor, S-(4-nitrobenzyl)-6-thioinosine (NBTI), were immersion-stored at 0 degrees C for 9 hr. Function was assessed after 30 min of working reperfusion. Function of unstored fresh hearts served as controls and poststorage recovery is reported as percentage of control function. Poststorage heart rate in all groups returned to control level after reperfusion. Recovery of other functional parameters in the no-NBTI group was as follows: aortic flow (AF), 56.2 +/- 4.6%; coronary flow (CF), 53.9 +/- 3.2%; cardiac output (CO), 55.5 +/- 4.0%; systolic pressure, 81.6 +/- 2.5%; work, 47.0 +/- 4.2%; and coronary vascular resistance (CVR), 157.1 +/- 7.8% of control. NBTI improved functional recovery in a dose-dependent fashion; the maximal improvement was seen at a dose of 5 nM, in which the recovery was: AF, 78.1 +/- 3.4%; CF, 73.5 +/- 4.4%; CO, 76.7 +/- 3.6%; work, 70.7 +/- 5.0%; and CVR, 127.5 +/- 4.5% of control (P < 0.05 vs. no-NBTI). The ADO A1-receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (0.1 microM) blocked the effects of 5 nM NBTI; the recovery of AF, CF, CO, work, and CVR decreased to 62.8 +/- 8.0%, 58.3 +/- 5.0%, 61.5 +/- 3.9%, 54.4 +/- 4.5%, and 163.8 +/- 12.7% of control, respectively (P < 0.05 vs. 5 nM NBTI). Tissue ADO content in 5 nM NBTI hearts at the end of storage was 0.075 +/- 0.025 mumol/g dry wt, which was significantly elevated from 0.016 +/- 0.004 mumol/g dry wt in no-NBTI hearts. Purine release during initial reperfusion was delayed in 5 nM NBTI hearts, indicating the inhibition of nucleoside transport by NBTI. But NBTI treatment did not improve end-storage or end-reperfusion myocardial ATP. In conclusion, the addition of NBTI to cardioplegic solution enhanced tissue ADO and improved poststorage function of the hypothermically stored rat heart. The effect is ADO A1-receptor mediated without invoking energy conservation.

Wavefront amplitude distribution in the female breast

Ultrasound measurements of a large population of wavefronts transmitted through female breasts at 3 and 4 MHz show that the wavefront amplitude distribution is close to Rayleigh. This finding is consistent with a fully developed scatter field, implying that the scatter energy removed from the coherent incident beam dominates the wavefront. The wavefront received from an inhomogeneous medium is the superposition of an incident wave plus a scattered wave. If the scattered field is weak, the received field is dominated by the incident field and the wavefront amplitude distribution is Rician. If the scattered field is strong, the received field is primarily the scattered field and the wavefront amplitude distribution is Rayleigh. If, in addition to scattering, refraction between bodies of different refractive indexes occurs, the total net effect on the wavefront amplitude distribution is the same as for strong scattering. This is what we have observed in the highly refractive female breast. This result has implications for the design of high lateral-resolution echo scanners that will incorporate adaptive phase deaberration algorithms. The published algorithms were developed for weak scattering and therefore may not be powerful enough. Alternatives have to be found to deaberrate the severe wavefront distortion in the breast.

Isolation of a monocot 3-hydroxy-3-methylglutaryl coenzyme A reductase gene that is elicitor-inducible

The rice (Oryza sativa) phytoalexins, momilactones and oryzalexins, are synthesized by the isoprenoid pathway. An early step in this pathway, one that is rate-limiting in mammalian systems, is catalyzed by the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). A gene that encodes this enzyme has been isolated from rice, and found to contain an open reading frame of 1527 bases. The encoded protein sequence of the rice HMGR appears to be conserved with respect to other HMGR proteins, and 1 or 2 membrane-spanning domains characteristic of plant HMGRs are predicted by a hydropathy plot of the amino acid sequence. The protein is truncated at its 5' end, and shows reduced sequence conservation in this region as compared to other plant sequences. The rice genome contains a small family of HMGR genes. The isolated gene, HMGR I, is expressed at low levels in both vegetative and floral organs of rice plants. It is not induced in plants by wounding, but is strongly and rapidly induced in suspension cells by a fungal cell wall elicitor from the pathogen Magnaporthe grisea, causal agent of rice blast disease. This suggests that HMGR I may be important in the induction of rice phytoalexin biosynthesis in response to pathogen attack, and therefore may play a key role as a component of the inducible defense mechanism in rice.

Transcutaneous ultrasound of the cervical esophagus in patients with esophageal carcinoma

Transcutaneous ultrasound of the cervical esophagus was performed in 46 patients with esophageal carcinoma and in 35 controls. The former had 24 upper segmental lesions and 22 lower segmental lesions. The level of the sternoclavicular joint was used to divide the esophagus into the upper segmental (USE) and lower segmental esophagus (LSE). The anterior esophageal wall thickness and luminal dimensions were measured before and immediately after phonation. The mean wall thickness in the controls was 1.8 mm before phonation and 2.1 mm after phonation, with a significant difference (t test, P < 0.05). The mean wall thickness in the USE carcinoma group was 4.3 mm and 4.4 mm before and after phonation respectively. There was a significant difference between the controls and USE carcinoma groups (t test, P < 0.05). The cross sectional area, which was calculated as the product of anterio-posterior and lateral diameters, averaged 28 mm2 before phonation in the controls and increased to 44 mm2 after phonation (t test, P < 0.05). The mean cross sectional area in the USE carcinoma group was significantly smaller before phonation than that in the controls (t test, P < 0.05) and showed little change after phonation. No significant difference was found between LSE carcinoma and control groups. Transcutaneous ultrasound appears to be a promising non-invasive method of investigation for cervical esophageal carcinoma.

Experimental studies of the inhibitory effects of green tea catechin on mice large intestinal cancers induced by 1,2-dimethylhydrazine

Three hundred Kunming mice were randomly divided into six groups (half males and half females in each group). Group 1 was the positive control group, Groups 2, 3, 4 and 5 were experimental groups and Group 6 was used as the solvent control group. Mice in Groups 1-4 were injected with 1,2-dimethylhydrazine (1,2-DMH) (20 mg/kg body wt.) solution subcutaneously once a week from the 2nd week to the 20th week. From the 1st week to the 23rd week, mice in Groups 2, 3 and 4 were given catechin (1 mg/mouse), catechin (2 mg/mouse) and EGCG (2 mg/mouse), respectively, five times a week. Mice in Group 5 received only catechin (3 mg/mouse) five times a week from the 1st to the 23rd week. Mice in Group 6 were injected with an equal volume of 1 mmol EDTA solution subcutaneously once a week from the 2nd to the 20th week. At the end of the 27th week, all the mice were killed by cervical dislocation (Zhu, Q.H. and Zhu, Q.F. (1991) Laboratory Animal Science, 1st edition. The Junior Educational Publisher, Guangdong). Pathological examinations indicated that the incidence of large intestinal cancers occurring in Group 1 was 80%, significantly higher than that in Groups 2, 3 and 4 (p < 0.001). No tumors were found in Groups 5 and 6. This might suggest that green tea has preventive effects on large intestinal cancer induction in spite of the different doses of catechin. Immunohistochemistry studies showed that green tea catechins could enhance the activity of superoxide dismutase (SOD) in tissues.

Measurement by confocal laser scanning microscopy of the volume of epidermal nuclei in thick skin sections

The mean volume and shape of nuclei assessed in standard tissue sections by means of stereologic and morphometric methods are associated with prognosis in tumors of different sites. Thus, accurate quantification of the volume and shape of cell nuclei can be important for cancer patients and also may be useful for a better understanding of basic cellular events, such as growth and differentiation. Confocal laser scan microscopy (CLSM) makes it possible to obtain image sets consisting of very thin serial optical slices from thick tissue sections. These images can be used with digital image processing to construct a three-dimensional (3-D) model of individual nuclei. We used CLSM to study a 50-micron-thick paraffin section of a skin biopsy. Image processing was applied to the CLSM images to precisely segment epidermal nuclei from the background, and serial two-dimensional (2-D) binary images were created. Alignment of the 2-D images that form the 3-D model of the original nuclei was carefully controlled. The series of 2-D binary images was connected with an algorithm to form the 3-D model of each complete nucleus and organized for the 3-D visualization and analysis using a 3-D volume rendering method. In this way we measured the volume and surface area of 22 intact epidermal nuclei. The mean nuclear volume was 174.7 micron3, the standard deviation of the volume 26.47 micron3, the mean surface area 168.0 micron2 and the standard deviation of the surface area 22.00 micron2.(ABSTRACT TRUNCATED AT 250 WORDS)

Antifreeze glycoproteins from antarctic notothenioid fishes fail to protect the rat cardiac explant during hypothermic and freezing preservation

The antarctic notothenioid fishes avoid freezing through the action of circulating antifreeze glycoproteins (AFGPs). This study investigated whether AFGPs could serve as cryoprotectants for the isolated rat heart under three different storage conditions. (1) Hearts were flushed with 15 mg AFGP/ml cardioplegic solution (CP) and stored for 9 h at 0 degrees C. This AFGP concentration has been reported to protect pig oocytes during hypothermic storage. (2) Hearts were flushed with 10 mg AFGP/ml CP-14 and stored frozen at -1.4 degrees C for 3 h. At this concentration the AFGPs significantly reduce the solution freezing point and also change the crystal morphology from dendritic to spicular. (3) Hearts were flushed with 10 micrograms AFGP/ml CP-15 and stored frozen at -1.4 degrees C for 5 h. At this low concentration the AFGPs have a strong inhibitory effect on ice recrystallization, but have little effect on the freezing point and less apparent effect on the crystal habit. After hypothermic or freezing storage, the functional viability was assessed by determining cardiac output (CO) during working reperfusion. No difference in CO was found between AFGP-treated and untreated hearts after 9 h of 0 degree C storage. CO in hearts frozen in CP-14 without AFGPs recovered to 50% of the freshly perfused control hearts. Hearts frozen in the presence of high concentrations of AFGPs (10 mg/ml CP-14) failed to beat upon thawing and reperfusion, although their tissue ice content was less than that found in hearts without AFGP treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of cefazolin in promoting ovine tracheal epithelial repair

Inhalation of toxic materials has been shown injurious to the upper airways. Because secondary infection can slow the repair process, we undertook this study to determine the efficacy of antibiotic therapy in promoting the healing process of acute tracheal wounds. In 18 anesthetized sheep, a portion of the cervical trachea was exposed to smoke from smoldering cotton cooled to 38 degrees C. Nine received the broad-spectrum antibiotic, cefazolin, while none received saline placebo. At 13 days after injury, nonciliated and ciliated cell counts were 75% and 33% respectively of noninjured trachea receiving placebo, while in those receiving cefazolin, nonciliated and ciliated cell counts increased to 93% and 114% of paired noninjured trachea, respectively. We suggest that cefazolin therapy allows cell proliferation and differentiation to proceed more rapidly than observed with placebo therapy and thus may be a helpful augmentor to the healing of an acute airway injury.

Adenosine deaminase inhibitor in cardioplegia enhanced function preservation of the hypothermically stored rat heart

Adenosine (ADO) has been shown to be protective to the ischemic-reperfused myocardium. This study tested the hypothesis that inhibition of myocardial adenosine deaminase during cold storage will elevate tissue ADO content, improve the cardiac function, and preserve ATP. The isolated rat hearts (6-9 hearts/group) were flushed with a cardioplegic solution containing 0-75 microM erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and immersion-stored at 0 degree C for 9 hr. Function was assessed after 30 min working reperfusion. Function of the unstored hearts (n = 11, mean +/- SE) including heart rate (293 +/- 13 bpm), aortic flow (AF; 52.5 +/- 1.1 ml/min), coronary flow (CF; 23.5 +/- 1.3 ml/min), cardiac output (CO; 76.0 +/- 2.1 ml/min), systolic pressure (SP; 136 +/- 2 mmHg), diastolic pressure (DP; 63 +/- 1 mm Hg), work (90.5 +/- 3.4 g-m/min), and coronary vascular resistance (CVR; 2.77 +/- 0.14 mmHg-min/ml) served as controls. Heart rate in all stored hearts returned to normal after reperfusion. Recovery of other function in no-EHNA group was: AF, 52 +/- 7; CF, 55 +/- 5; CO, 53 +/- 6; SP, 79 +/- 4; DP, 93 +/- 3; work, 47 +/- 7; and CVR, 171 +/- 15% of control. EHNA improved functional recovery in a dose-dependent fashion. At the optimal concentration of 25 microM, the recovery was: AF, 83 +/- 6; CF, 68 +/- 4; CO, 78 +/- 5; SP, 90 +/- 3; DP, 105 +/- 5; work, 77 +/- 8; and CVR 151 +/- 9% of control. ADO A1 receptor antagonists, 8-phenyltheophylline (1 microM) and 1,3-dipropyl-8-cyclopentylxanthine (0.1 microM) blocked the effects of 25 microM EHNA; the recovery of CO was reduced to 65 +/- 3 and 50 +/- 2% of the control, respectively. Tissue ADO content in 25 microM EHNA hearts at the end of storage was 95 +/- 19 nmol/g dry wt, which was significantly elevated from 15 +/- 3 nmol/g dry wt in no-EHNA hearts. EHNA also caused a 45-fold increase in the release of ADO over no-EHNA group during the first 10 min of reperfusion. But EHNA treatment did not cause any change in either end-storage or end-reperfusion myocardial ATP levels. Thus EHNA in cardioplegic solution inhibited cardiac ADO catabolism during long-term hypothermic storage and improved function preservation partially via an ADO A1 receptor-mediated mechanism without invoking ATP conservation.

[Studies on anti-inflammatory protein from the extraction of the larva of Parasa sinica Moore]

As a kind of anti-inflammatory protein fractionated and purified from the larva of parasa sinica, CCP (ip) has a significant anti-inflammatory effect on ear odema induced by croton oil in mice. Its ID50 is 1.6mg/kg, but a dose of 2.5mg/kg can also significantly inhibit the rat ankle odema induced by carrageenan and egg white.

In situ preparation of rat tracheal basal cells

The primary function of basal cells is to attach columnar epithelium to the basal lamina. They may also have limited stem cell potential, but very little is known of other biological functions. Basal cells lie on the basal lamina beneath the ciliated and secretory cells and do not reach the surface of the epithelium. The position of the cell beneath the ciliated and secretory cell epithelium makes their in situ study difficult. In order to further aid in the study of basal cells, we have developed an in situ preparation technique in which ciliated and secretory cells are removed. Treatment of rat tracheas with a 20 mM Na2 EDTA solution, pH 7.4, results in partial removal of columnar epithelium from the basal lamina. The percent of denuded columnar epithelial cells per mm of basal lamina is 43.9 +/- 7.8% at 60 min, 47.6 +/- 8.4% at 90 min, and 52.6 +/- 2.7% at 120 min. The viability of the exposed basal cells was the same at both 60 and 90 min of treatment (79.4 +/- 7.8 and 78.0 +/- 8.5, respectively). Morphologically, the exposed basal cells are attached to the basal lamina by hemidesmosomes and are similar to those in the intact animal.

[Diagnosis of subclinical hepatic encephalopathy: a parallel and comparative study between the evoked potentials and the performance psychometric tests]

The authors report the results of a parallel study between the three kinds of evoked potentials (EP) i.e. visual, brainstem auditory and somatosensory evoked potentials (VEP, BAEP and SEP) and psychometric tests in 30 posthepatitic cirrhotic patients. The results were compared with those from 20 peptic ulcer patients in healing stage. Psychometric tests were abnormal in 65.5% of the cirrhotic and in none of the peptic ulcer patients. The three kinds of evoked potentials were abnormal in 58.6% of the cirrhotic patients and in 5% of the peptic ulcer patients. The VEP, BAEP and SEP was abnormal in 13.3%, 10% and 50% of the cirrhotics respectively. The results of this study showed: of the three kinds of evoked potentials, SEP is the most sensitive one. The evoked potentials and the performance psychometric tests are complementary in the diagnosis of subclinical hepatic encephalopathy.

[Preoperative examination of patients with thyroid nodules by high-resolution real-time ultrasonography]

Fifty patients with thyroid nodules were examined by high-resolution real-time ultrasonography (US) before surgery. Of this series, the sonographic features of 54 nodules in 41 cases were classified according to internal echogenicity, cystic components, margin, sound transmission, anterior extra-thyroid extension, and peripheral "halo" sign. Except for the last, the differences between benign and malignant nodules were statistically significant (P < 0.05, P < 0.01 or P < 0.001). The comparisons of US and palpation examination (PE) with postoperative pathological findings were undertaken in these 50 cases, respectively. The sensitivity and accuracy for US were much higher than those for PE (sensitivity, 97% vs. 77%; accuracy, 97% vs. 76%). Our results show that by analyzing some sonographic characteristics, it may be possible to differentiate benign from malignant lesions and owing to its higher sensitivity and accuracy, ultrasonography is a better choice of the scrutiny into thyroidal gland.

Subzero nonfreezing storage of the mammalian cardiac explant. I. Methanol, ethanol, ethylene glycol, and propylene glycol as colligative cryoprotectants

We employed hyperosmotic concentrations of penetrating cryoprotective agents (CPA) to store the isolated rat hearts unfrozen at subzero temperatures. The effect of acute exposure to CPA was assessed by flushing the hearts with CP-14, a cardioplegic solution, containing methanol (MeOH), ethanol (EtOH), ethylene glycol (EG), or propylene glycol (PG) for 2 min and reperfusing immediately with Krebs-Henseleit buffer in a working-heart model. The maximal doses that did not cause irreversible suppression of heart function were: MeOH, 1.78 M; EtOH, 1.27 M; EG, 0.84 M; and PG, 0.87 M. For nonfreezing storage, the hearts were flushed with CP-14 containing the highest tolerable concentrations of MeOH, EtOH, EG, or PG, stored for 6 h at -3.7, -2.8, and -1.4 degrees C, respectively, and then reperfused. Control cardiac output (CO) was 76.2 +/- 1.8 ml/min. Post-reperfusional recovery of CO was 86% in MeOH hearts, 82% in EtOH hearts, 76% in EG hearts, and 79% in PG hearts. Thus MeOH offered not only the least cardiac-suppressing effect but the lowest nonfreezing storage temperature. When storage time was extended, recovery and myocardial ATP level decreased with time in hearts flushed with CP-14 + 1.78 M MeOH and stored at -3.7 degrees C. The decay of function was faster than the decay of ATP level, suggesting energy was better preserved than function. The low return of function, however, may be related to CPA toxicity, osmotic stress, and ischemia/reperfusion injury. Nonfreezing storage at subzero temperatures using these CPAs may provide a novel approach to long-term cardiac preservation.

A rabbit model for human cytomegalovirus-induced chorioretinal disease

AD169, a well-characterized laboratory strain of human cytomegalovirus (HCMV), was used to establish an animal model of progressive HCMV chorioretinal disease by injection of 10(5) pfu into the rabbit vitreous. Chorioretinal, vitreous, and pulmonary disease were monitored by HCMV recovery, clinical observation, antigen localization, and histopathology. Vitritis and focal areas of immune cellular infiltrates were seen in inner retinal layers on days 2-4 after inoculation. Disease progressed with more severe vitritis and to involve the outer retinal layers in areas of mixed monocytic cellular infiltrates, retinal destruction, choroidal edema, and congestion. HCMV was recovered from chorioretinal cell sonicate cultures in titers ranging from 10(4) to 10(5) pfu during peak disease, and HCMV antigens were detected focally by immunofluorescence in retinal layers on days 2 and 4 after inoculation. A rabbit model of HCMV chorioretinitis similar to human CMV disease allows investigation of HCMV pathogenesis and new antiviral therapies and evaluation of immune system modulation of the HCMV ocular infection.

Dual-wavelength frequency-stabilized CO(2) laser with four operating frequencies

A dual-wavelength frequency-stabilized CO(2) laser with a wideband dispersion cavity is described. A sequence of four operating frequencies can be composed on only one P-P line pair. The signature in this multifrequency CO(2) laser is unvaried and permanent. The frequency stabilities of simultaneous oscillations are approximately several parts in 10(10) (sample time 10 s).

Proton pumps populate the contractile vacuoles of Dictyostelium amoebae

Amoebae of the eukaryotic microorganism Dictyostelium discoideum were found to contain an interconnected array of tubules and cisternae whose membranes were studded with 15-nm-diameter "pegs." Comparison of the ultrastructure and freeze-fracture behavior of these pegs with similar structures found in other cells and tissues indicated that they were the head domains of vacuolar-type proton pumps. Supporting this identification, the pegs were observed to decorate and clump when broken amoebae were exposed to an antiserum against the B subunit of mammalian vacuolar H(+)-ATPase. The appearance of the peg-rich cisternae in quick-frozen amoebae depended on their osmotic environment: under hyperosmotic conditions, the cisternae were flat with many narrow tubular extensions, while under hypo-osmotic conditions the cisternae ranged from bulbous to spherical. In all cases, however, their contents deep etched like pure water. These properties indicated that the interconnected tubules and cisternae comprise the contractile vacuole system of Dictyostelium. Earlier studies had demonstrated that contractile vacuole membranes in Dictyostelium are extremely rich in calmodulin (Zhu, Q., and M. Clarke, 1992, J. Cell Biol. 118: 347-358). Light microscopic immunofluorescence confirmed that antibodies against the vacuolar proton pump colocalized with anti-calmodulin antibodies on these organelles. Time-lapse video recording of living amoebae imaged by interference-reflection microscopy, or by fluorescence microscopy after staining contractile vacuole membranes with potential-sensitive styryl dyes, revealed the extent and dynamic interrelationship of the cisternal and tubular elements in Dictyostelium's contractile vacuole system. The high density of proton pumps throughout its membranes suggests that the generation of a proton gradient is likely to be an important factor in the mechanism of fluid accumulation by contractile vacuoles.

Regulation of antibody responses: the role of complement and adhesion molecules

To analyze the importance of cell surface-associated molecules in modulating the immune response by facilitating T/B cell interaction, we used the T cell-dependent antigen, bacteriophage phi X174. Taking advantage of "experiments of nature", we studied specific antibody synthesis in patients with deficiencies of complement components or of the adhesion molecule CD11/CD18 (leukocyte adhesion defect, LAD) and guinea pigs and dogs with early complement component deficiency. Following intravenous injection of bacteriophage phi X174 into normal subjects or animals, a primary response consisting of IgM, a secondary response consisting of IgM and IgG, and a tertiary, predominantly IgG response can be distinguished. Patients and guinea pigs deficient of early complement component and LAD patients responded to repeated phage immunization with depressed antibody titers, lack of or inadequate amplification, and failure to switch from IgM to IgG, suggesting a defect in generating antigen-specific memory cells. Several mechanisms have to be considered: (i) The complement portion of the antigen-antibody complement complex facilitates the accumulation and trapping of antigen in lymphoid organs, thus improving the response to Ag at low concentrations. (ii) Immune complexes preferentially bind to antigen-specific B cells, cells expressing Fc receptors, or CR2 and CR3, the receptors for C3bi. (iii) The weak binding established between the MHC-II/Ag complex and the TCR complex is strengthened through the binding of several adhesion molecule pairs. (iv) Receptor-ligand binding initiates activation signals. The concept of binding/signaling via interacting molecules is further supported by the observation that mAb 60.3, recognizing the beta chain of CD11/CD18, blocks in vitro synthesis of antibody to bacteriophage by primed PBMC.