HCN2 overexpression in newborn and adult ventricular myocytes: distinct effects on gating and excitability

Ventricular pacemaker current (I(f)) shows distinct voltage dependence as a function of age, activating outside the physiological range in normal adult ventricle, but less negatively in neonatal ventricle. However, heterologously expressed HCN2 and HCN4, the putative molecular correlates of ventricular I(f), exhibit only a modest difference in activation voltage. We therefore prepared an adenoviral construct (AdHCN2) of HCN2, the dominant ventricular isoform at either age, and used it to infect neonatal and adult rat ventricular myocytes to investigate the role of maturation on current gating. The expressed current exhibited an 18-mV difference in activation (V(1/2) -95.9+/-1.9 in adult; -77.6+/-1.6 mV in neonate), comparable to the 22-mV difference between native I(f) in adult and neonatal cultures (V(1/2) -98.7 versus -77.0 mV). This did not result from developmental differences in basal cAMP, because saturating cAMP in the pipette caused an equivalent positive shift in both preparations. In the neonate, AdHCN2 caused a significant increase in spontaneous rate compared with control (88+/-5 versus 48+/-4 bpm). In adult, where HCN2 activates more negatively, the effect was evident only during anodal excitation, requiring significantly less stimulus energy than control (2149+/-266 versus 3140+/-279 mV. ms). Thus, ventricular maturational state influences the voltage dependence of expressed HCN2, resulting in distinct physiological impact of expressed channels in neonate and adult myocytes. The full text of this article is available at http://www.circresaha.org.

Determination of scutellarin in Erigeron breviscapus extract by liquid chromatography-tandem mass spectrometry

A quantitative assay for scutellarin by LC-MS-MS (negative ion mode) was developed. The scutellarin was extracted from dry Erigeron breviscapus. Significant ion suppression was observed, which could be eliminated by increasing the turboionspray interface temperature to 350 degrees C and by 1000-fold dilution of the extract with solvent. The calibration curve of scutellarin showed excellent linearity over a wide concentration range (0.01-100 microg/ml) (r=0.998), and the limit of detection was 15 pg/ml using a 10-microl injection volume. The analysis time was 4 min/sample.

Comparison of blood counts in venous, fingertip and arterial blood and their measurement variation

We compared routine blood pictures in venous, fingertip and arterial blood and their measurement variation. A pair of venous and fingertip blood samples were simultaneously collected from 24 volunteers, and another pair of venous and arterial samples from another 12 volunteers. The volunteers were healthy adults, aged 20-22 years, with males and females in equal numbers. Three aliquots of blood were taken from each person for three measurements of blood counts, including haemoglobin concentration and haematocrit, using an automatic haematology analyser. Compared to arterial blood, there was a significant increase of erythrocyte count (2.7%) and haematocrit (3.1%) in the venous blood. The total and large leucocyte counts were significantly higher (9.2% and 12.6%, respectively) in the fingertip blood than in the venous blood. There were a decreasing number of leucocytes in the fingertip blood with repeated sampling. The intermeasurement variation for total leucocyte or haemoglobin measurement was significantly larger as measured with the fingertip blood or arterial blood than with the venous blood. The intermeasurement coefficients of variation of haemoglobin (1.3%) and small leucocyte ratio or platelet (approximately 4.0%) measurements with venous and arterial blood were the smallest and largest, respectively. Volume of arterial plasma was diminished by 2-3% after microcirculation. Elevation of total leucocyte count in the fingertip blood was mainly due to the increase of granulocytes. Measurement with venous blood was of better precision than with fingertip or arterial blood.

Activated PAK4 regulates cell adhesion and anchorage-independent growth

The serine/threonine kinase PAK4 is an effector molecule for the Rho GTPase Cdc42. PAK4 differs from other members of the PAK family in both sequence and function. Previously we have shown that an important function of this kinase is to mediate the induction of filopodia in response to activated Cdc42. Since previous characterization of PAK4 was carried out only with the wild-type kinase, we have generated a constitutively active mutant of the kinase to determine whether it has other functions. Expression of activated PAK4 in fibroblasts led to a transient induction of filopodia, which is consistent with its role as an effector for Cdc42. In addition, use of the activated mutant revealed a number of other important functions of this kinase that were not revealed by studying the wild-type kinase. For example, activated PAK4 led to the dissolution of stress fibers and loss of focal adhesions. Consequently, cells expressing activated PAK4 had a defect in cell spreading onto fibronectin-coated surfaces. Most importantly, fibroblasts expressing activated PAK4 had a morphology that was characteristic of oncogenic transformation. These cells were anchorage independent and formed colonies in soft agar, similar to what has been observed previously in cells expressing activated Cdc42. Consistent with this, dominant-negative PAK4 mutants inhibited focus formation by oncogenic Dbl, an exchange factor for Rho family GTPases. These results provide the first demonstration that a PAK family member can transform cells and indicate that PAK4 may play an essential role in oncogenic transformation by the GTPases. We propose that the morphological changes and changes in cell adhesion induced by PAK4 may play a direct role in oncogenic transformation by Rho family GTPases and their exchange factors.

Time-frequency representations of Lamb waves

The objective of this study is to establish the effectiveness of four different time-frequency representations (TFRs)--the reassigned spectrogram, the reassigned scalogram, the smoothed Wigner-Ville distribution, and the Hilbert spectrum--by comparing their ability to resolve the dispersion relationships for Lamb waves generated and detected with optical techniques. This paper illustrates the utility of using TFRs to quantitatively resolve changes in the frequency content of these nonstationary signals, as a function of time. While each technique has certain strengths and weaknesses, the reassigned spectrogram appears to be the best choice to characterize multimode Lamb waves.

The serine/threonine kinase PAK4 prevents caspase activation and protects cells from apoptosis

The serine/threonine kinase PAK4 was identified first as an effector molecule for the Rho GTPase Cdc42. PAK4 differs from other members of the PAK family both in sequence and function. Previously we have shown that an important function of this kinase is to mediate the induction of filopodia in response to activated Cdc42. Studies with a constitutively active PAK4 mutant have shown that it also has a role in promoting anchorage-independent growth, an important hallmark of oncogenic transformation. Here we show that another function of PAK4 is to protect cells against apoptotic cell death. Expression of wild-type or constitutively active PAK4 delays the onset of apoptosis in response to tumor necrosis factor alpha stimulation, UV irradiation, and serum starvation. Consistent with an antiapoptotic function, expression of PAK4 leads to an increase in phosphorylation of the proapoptotic protein Bad and an inhibition of caspase activation.

[Alterations of pulmonary surfactant during Pseudomonas aeruginosa pneumonia of immunocompromised rats]

OBJECTIVE

To analyze the alterations of pulmonary surfactant in immunocompromised host with Pseudomonas aeruginosa (PA) pneumonia.

METHODS

50 rats were randomly divided into two groups, one immunosuppressed with cyclophosphamide and cortisone acetate as ICH group, another as control group (CON), their lung tissue and bronchoalveolar lavage fluid (BALF) were collected before PA challenging and 3 h, 6 h, 9 h, 24 h after PA challenging intratracheally, wet/dry ratio (W/D) of lung tissue were measured, concentrations of total protein (TP), total phospholipids (TPL), disaturated phosphatidylcholine (DSPC) and surfactant protein A (SP-A) in BALF were analyzed.

RESULTS

The ratios of DSPC/TPL and DSPC/TP decreased significantly in both ICH and CON groups after PA infection, there were not significant differences between the two groups, no change in the concentrations of TPL and DSPC. Concentration of SP-A and SP-A/TP in ICH group decreased remarkably 6 h after PA pulmonary infection than before [(1.8 +/- 1.1) microgram/ml vs (4.2 +/- 1.5) microgram/ml, (1.4 +/- 0.7) microgram/mg vs (11.7 +/- 8.1) microgram/mg, P < 0.05], meanwhile there were no significant alterations in CON group. W/D and TP concentrations increased in both groups after PA challenging, however the alterations were much greater in ICH group (P < 0.05). Alterations of SP-A appeared a negative correlation with alterations of TP and W/D (r = -0.793, P < 0.01, r = -0.769, P < 0.01). The ratios of SP-A/TPL and SP-A/DSPC decreased significantly 6 h after PA challenging than before, the ratios were much lower in ICH group than in CON group during 6 h-9 h after PA inoculation.

CONCLUSION

After PA pulmonary infection, alterations of phospholipids could initially appear a relative decrement of DSPC during acute phase of infection, much remarkable decrease of SP-A in ICH group could be associated with the more severe lung injury, alterations of SP-A were more obvious than surfactant lipids in ICH.

[The efficiency of algae removal from drinking water by ferrate]

This paper studied the efficiency of algae removal by ferrate from two kinds of raw water which were collected from Donghu and Tiegang reservoir respectively. The experimental results showed that the removal efficiency of algae reached about 95% only through PAC coagulation when the raw water was extracted from Donghu reservoir in which most of algae was Chlorella. But dealing with Tiegang raw water in which the majority of algae were Oscillatoria, terrate was used as pre-oxidant coupling with PAC coagulation not only using PAC to flocculate and the efficiency of algae removal could be up to 97.85%. However this treatment method using ferrate as pre-oxidant overmatched the traditional method prechlorination for algae removal.

Relationship between the burden of Pneumocystis carinii, the inflammatory reaction and lung injury in Pneumocystis carinii pneumonia

OBJECTIVE

To study the relationship between the burden of Pneumocystis carinii (P. carinii) and the inflammatory reaction and biochemical markers in bronchoalveolar lavage fluids (BALF) in a rat model of P. carinii pneumonia (PCP).

METHODS

Clean grade 50 male Sprague-Dawley rats were immunosuppressed by a subcutaneous injection of 25 mg cortisone acetate twice a week for 8-12 weeks; the PCP model was successfully induced in 14 rats. The inflammatory reaction and biochemical markers of the activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and type IV collagenase (matrix metalloproteinases, MMP-2, MMP-9) as well as the values of total protein (TP) and albumin (ALB) in BALF between the mild burden group of P. carinii (involved alveoli < 25% per 100 alveoli, Group A) and the moderate to severe burden group (involved alveoli > or = 25% per 100 alveoli, Group B) were measured. The other six clean grade SD rats served as normal control group (Group C).

RESULTS

The total white cell count in BALF was higher in Group B [(6.8 +/- 1.7) x 10(6)/L] than in Group A [(3.8 +/- 1.2) x 10(6)/L] (P < 0.01); however, there were no differences in white cell differentiation. Assays of biochemical markers showed that ALB in BALF in Group B (0.893 +/- 0.469 g/L) was increased in comparison with Group A (0.262 +/- 0.169 g/L); it was only 0.026 +/- 0.021 g/L in Group C. The contents of TP and activities of LDH were higher in Group B (TP 1.756 +/- 0.706 g/L, LDH 2580 +/- 550 U/L) than in Group A (TP 0.784 +/- 0.553 g/L, LDH 1410 +/- 620 U/L); the values of TP and LDH were 0.063 +/- 0.020 g/L and 370 +/- 250 U/L respectively in Group C. The activity of Type IV collagenase, including MMP-2 and MMP-9, was higher in Group B than in Group A (P < 0.01) (MMP-2: 1102 +/- 169 grey value vs 459 +/- 274 grey value; MMP-9: 1218 +/- 257 grey value vs 449 +/- 225 grey value). There was no activity of Type IV collagenase in BALF of Group C. No statistically significant difference was observed in ALP between the groups B and A.

CONCLUSIONS

These results indicate that there is a significant correlation between the burden of P. carinii in lung tissues and the inflammatory reaction as well as biochemical markers of the resultant activity of lung injury.

Inactivation of monomeric sarcosine oxidase by reaction with N-(cyclopropyl)glycine

Monomeric sarcosine oxidase (MSOX) catalyzes the oxidative demethylation of sarcosine (N-methylglycine) and contains covalently bound flavin adenine dinucleotide (FAD). The present study demonstrates that N-(cyclopropyl)glycine (CPG) is a mechanism-based inhibitor. CPG forms a charge transfer complex with MSOX that reacts under aerobic conditions to yield a covalently modified, reduced flavin (lambda(max) = 422 nm, epsilon(422) = 3.9 mM(-1) cm(-1)), accompanied by a loss of enzyme activity. The CPG-modified flavin is converted at an 8-fold slower rate to 1,5-dihydro-FAD (EFADH(2)), which reacts rapidly with oxygen to regenerate unmodified, oxidized enzyme. As a result, CPG-modified MSOX reaches a CPG-dependent steady-state concentration under aerobic conditions and reverts back to unmodified enzyme upon removal of excess reagent. No loss of activity is observed under anaerobic conditions where EFADH(2) is formed in a reaction that goes to completion at low CPG concentrations. Aerobic denaturation of CPG-modified enzyme yields unmodified, oxidized flavin at a rate similar to the anaerobic denaturation reaction, which yields 1,5-dihydro-FAD. The CPG-modified flavin can be reduced with borohydride, a reaction that blocks conversion to unmodified flavin upon removal of excess CPG or enzyme denaturation. The possible chemical mechanism of inactivation and structure of the CPG-modified flavin are discussed.

[Influence of the subglottic secretion drainage on the morbidity of ventilator associated pneumonia in mechanically ventilated patients]

OBJECTIVE

To assess the influence of the subglottic secretion drainage on the morbidity of ventilator associated pneumonia in mechanically ventilated patients.

METHODS

All cases requiring intubation in SICU were intubated with a special type endotracheal tube which has a small-bore cannula in its wall for subglottic secretion drainage. They were randomly divided into two groups received subglottic secretion drainage(SSD) and usual care(NON-SSD) respectively. Bacterial culture of samples from the oropharynx, subglottic secretions and lower respiratory tract were obtained periodically. The amount of subglottic secretion aspirated daily, ventilated days and the number of cases with VAP were recorded. Etiologic diagnosis of VAP was based on the quantitative bacterial culture of secretions obtained by protected specimen brush(PSB).

RESULTS

The morbidity of VAP in the SSD group (n = 35) (23%) was lower than that in the NON-SSD group (n = 33) (45%) (P < 0.05). The difference was due to the significant reduction of VAP caused by gram-positive cocci and Haemophilus influenzae organisms. However, no difference was observed in the incidence of VAP caused by non-fermental bacteria. After intubation the onset of VAP was delayed in SSD group (14 +/- 8 day) as compared with the NON-SSD group (6 +/- 4 day) (P < 0.05). The same organisms were isolated by PSB among 61% (14/23) patients with VAP as what were previously isolated from the subglottic secretions.

CONCLUSIONS

The presence of subglottic secretion may be an origin of the pathogenetic organisms of VAP. The morbidity of VAP in mechanically ventilated patients can be reduced by SSD, especially for VAP caused by gram-positive cocci and Haemophilus influenzae organisms. SSD may be a simple and effective method for prevention of VAP.

[G-protein modulates the inhibition of angiotensin II on BKCa in ECV304]

OBJECTIVE

To investigate the effect of angiotensin II (A II) on maxi-conductance calcium-activated potassium channel(BKCa) activity in ECV304 cell membrane, and the possible involvement of G-protein.

METHODS

Cell-attached configuration of patch clamp technique was employed to record the current of BKCa in ECV304.

RESULTS

10(-7) mol/L angiotensin II inhibited the BKCa activity. Current amplitude and open probability were decreased, open time was shortened and close time was increased. G-protein activation could eliminate the inhibition of A II.

CONCLUSIONS

A II significantly decreased the activity of BKCa in ECV304, which might depolarize the membrane, and the stability of membrane might change. Thus endothelial cell dysfunction might be induced. G-protein activation was involved in the regulation of the above A II inhibition process.

Sympathetic innervation alters activation of pacemaker current (If) in rat ventricle

Pacemaker current (If) exists in both neonatal and adult ventricles, but activates at more negative voltages in the adult. This study uses whole-cell patch clamp to investigate the factors that may contribute to the maturational shift of If, comparing neonatal rat ventricular myocytes that were cultured for 4-6 days either alone, in co-culture with sympathetic nerves, or with neurotransmitters chronically present in culture. If recorded from nerve-muscle co-cultures had a significantly more negative and shallower activation-voltage relation than that from control muscle cultures, which was reflected in the midpoint potential (V50) and slope factor (K) of activation. This effect of innervation was prevented by the sustained presence in the culture of the alpha1-adrenergic antagonist prazosin (Pz) at 10(-7) M. In parallel experiments, myocytes treated with noradrenaline (NA) at 10(-7) M or neuropeptide Y (NPY) at 10(-7) M during culture had the same If activation as control cells, but cells treated with NA and NPY together had a significantly more negative and shallower activation curve. Maximum conductance and reversal potential were unchanged. The effect of chronic exposure to NA + NPY was prevented by the sustained presence of either Pz or the NPY Y2 selective antagonist T4-[NPY(33-36)]4 (3.5 x 10(-7) M) in the culture, indicating a requirement for both alpha1-adrenergic and NPY Y2 activation. Substituting NA with the alpha1A-adrenergic selective agonist A61603 (5(-10) x 10(-9) M), in the presence of NPY, did not alter If, suggesting the involvement of alpha1B- rather than alpha1A-adrenoceptors. Further, sequential exposure to NPY followed by NA was effective in reproducing the action of chronic simultaneous exposure to these agonists, but sequential exposure to NA followed by NPY was ineffective. The results are consistent with past studies indicating that NPY affects the functional expression of the alpha1B-adrenergic cascade and suggest that sympathetic innervation induces a negative shift of If in ventricle via a combined action at alpha1B-adrenergic and NPY Y2 receptors. This effect of innervation probably contributes to the developmental maturation of If activation.

Investigation of the SERS behaviour of porphyrins with different surface concentrations on electrochemically prepared Ag-surface

Surface-enhanced Raman scattering (SERS) spectra, taken with 632.8 nm excitation are reported for the water-soluble tetrakis(3-N-methylpyridyl)porphyrin chloride (TMPyP(3)), tetrakis(4-N-methylpyridyl)porphyrin chloride (TMPyP(4)) and Sn(IV)tetrakis(4-N-methylpyridyl)porphyrin chloride (Sn(IV)TMPyP(4)) using an electrochemically prepared Ag surface with an area ca. 12.56 mm2. It was found that the spectra vary as increasing amounts of the compounds are placed on the surface, with surface concentrations in the approximate range 1000-5 pmol/12.56 mm2. We suggest that the reasons for the changes be that the reaction means between porphyrin molecules and Ag surface is different and the porphyrin macrocyclic molecules adopt different orientation as the surface concentrations decrease.

[Early arthroscopic reconstruction in treatment of acute complete rupture of anterior cruciate ligament]

OBJECTIVE

To early reconstruct acute and complete rupture of anterior cruciate ligament (ACL) and treat combined injuries for the recovery of knee joint stability.

METHODS

Ten cases of acute complete rupture of anterior cruciate ligament and medial collateral ligament were treated arthroscopically by anterior cruciate ligament reconstruction using patellar tendon autograft fixed with interference screw from February 1998 to March 1999.

RESULTS

Follow-up ranged from 5 months to 1 year and 3 months (average 10 months). Clinical results showed that the stability of knee joint was satisfactory in the early stage.

CONCLUSIONS

Acute the ACL rupture can be reconstructed arthroscopically in the early stage and the injuries were moderate, combined injuries could be treated at the same time, and the stability of knee joint could recover in the early stage after operation.

Expression of transforming growth factor-alpha, epidermal growth factor, and epidermal growth factor receptor in follicles of human ovarian tissue before and after cryopreservation

OBJECTIVE

To study the expression of transforming growth factor-alpha (TGF-alpha), epidermal growth factor (EGF), and EGF receptor in follicles of human ovarian tissue.

DESIGN

A retrospective, controlled comparative study.

SETTING

In vitro fertilization laboratory of a university hospital.

PATIENT(S)

Fifteen women with regular menstrual cycles who underwent laparoscopy and the biopsy of ovarian tissue.

INTERVENTION(S)

Paraffin sections were prepared from ovarian tissues, followed by immunohistochemical staining of TGF-alpha, EGF, and EGF receptor.

MAIN OUTCOME MEASURE(S)

Immunostaining for TGF-alpha, EGF, and EGF receptor in follicles of fresh and frozen ovarian tissues.

RESULT(S)

Immunoreactivities for TGF-alpha and EGF receptor were observed simultaneously in the oocytes of primordial, primary, preantral, and antral follicles. Strong staining for TGF-alpha and EGF receptor was present in thecal cells. The TGF-alpha and EGF receptor was also expressed in some granulosa cells of primary to antral follicles. The EGF only stained weakly in the oocytes of primordial and primary follicles and in thecal cells. There was no difference in staining patterns for TGF-alpha, EGF, and EGF receptor between fresh and frozen ovarian tissues.

CONCLUSION(S)

The TGF-alpha and EGF receptor was expressed in primordial to antral follicles, indicating a role of TGF-alpha in regulating follicular development through binding to the EGF receptor. Freeze-thawing did not substantially alter immunoreactivites for TGF-alpha, EGF, and EGF receptor in frozen ovarian tissue.

Histologic and ultrastructural evaluation of fresh and frozen-thawed human ovarian xenografts in nude mice

OBJECTIVE

To compare histologic and ultrastructural characteristics of fresh and frozen-thawed human ovarian cortical tissue grafted into nude mice.

DESIGN

Experimental prospective study.

SETTING

An academic research environment.

PATIENT(S)

Ovarian biopsy specimens were obtained from 13 women undergoing laparoscopy for tubal ligation or infertility.

ANIMAL(S)

Forty nude mice.

INTERVENTION(S)

A minilaparotomy was performed to place fresh and frozen-thawed ovarian grafts subcutaneously (sc) or intraperitoneally (ip). Removal of the ovarian grafts was performed at 24 days.

MAIN OUTCOME MEASURE(S)

[1] the follicular population, [2] fibrosis, [3] vascularization of the grafted tissue, and [4] ultrastructural evaluation.

RESULT(S)

A greater fibrosis relative surface area was noted in frozen-thawed transplanted tissue than in fresh transplants. Regardless of this fibrosis, a similar follicular density was observed in fresh and frozen-thawed ovarian tissue 24 days after transplantation. Active angiogenesis was proved by both immunohistochemical study of the vascular endothelial growth factor and morphometric study of the vascular network. Normal ultrastructural characteristics were noted in frozen-thawed ovarian biopsies.

CONCLUSION(S)

Angiogenesis allows implantation of the graft even if it has been cryopreserved and thawed similarly to implantation of fresh tissue. The greater fibrosis observed in grafts after cryopreservation and implantation does not seem to affect the primordial and primary ovocyte population and their ultrastructural characteristics, but further studies must be conducted to prove that after cryopreservation and transplantation, ovocytes may achieve full maturation and fertilization.

Phosphatidylserine-dependent adhesion of T cells to endothelial cells

Phosphatidylserine (PS) was exposed at the surface of human umbilical vein endothelial cells (HUVECs) and cultured cell lines by agonists that increase cytosolic Ca(2+), and factors governing the adhesion of T cells to the treated cells were investigated. Thrombin, ionophore A23187 and the Ca(2+)-ATPase inhibitor 2, 5-di-tert-butyl-1,4-benzohydroquinone each induced a PS-dependent adhesion of Jurkat T cells. A23187, which was the most effective agonist in releasing PS-bearing microvesicles, was the least effective in inducing the PS-dependent adhesion of Jurkat cells. Treatment of ECV304 and EA.hy926 cells with EGTA, followed by a return to normal medium, resulted in an influx of Ca(2+) and an increase in adhering Jurkat cells. Oxidised low-density lipoprotein induced a procoagulant response in cultured ECV304 cells and increased the number of adhering Jurkat cells, but adhesion was not inhibited by pretreating ECV304 cells with annexin V. PS was not significantly exposed on untreated Jurkat cells, as determined by flow cytometry with annexin V-FITC. However, after adhesion to thrombin-treated ECV304 cells for 10 min followed by detachment in 1 mM EDTA, there was a marked exposure of PS on the Jurkat cells. Binding of annexin V-FITC to the detached cells was inhibited by pretreating them with unlabelled annexin V. Contact with thrombin-treated ECV304 cells thus induced the exposure of PS on Jurkat cells and, as Jurkat cells were unable to adhere to thrombin-treated ECV304 cells in the presence of EGTA, the adhesion of the two cell types may involve a Ca(2+) bridge between PS on both cell surfaces. The number of T cells from normal, human peripheral blood that adhered to ECV304 cells was not increased by treating the latter with thrombin. However, findings made with several T cell lines were generally, but not completely, consistent with the possibility that adhesion to surface PS on endothelial cells may be a feature of T cells that express both CD4(+) and CD8(+) antigens. Possible implications for PS-dependent adhesion of T cells to endothelial cells in metastasis, and early in atherogenesis, are discussed.

[G-protein potentiates the activation of TNF-alpha on calcium-activated potassium channel in ECV304]

OBJECTIVE

Observe the effect of tumor necrosis factor-alpha (TNF-alpha) on calcium-activated potassium channel in ECV304 and the possible involvement of G-protein mediation in the action of TNF-alpha.

METHOD

Using the cell-attached configuration of patch clamp technique.

RESULTS

(1) the activity of high-conductance calcium-activated potassium channel (BKca) was recorded. Its conductance is (202.54 +/- 16.62) pS; (2) the activity of BKca was potentiated by 200 U/ml TNF-alpha; (3) G-protein would intensify this TNF-alpha activation.

CONCLUSIONS

TNF-alpha acted on vascular endothelial cell ECV304 could rapidly activate the activity of BKca. Opening of BKca resulted in membrane hyper-polarization which could increase electro-chemical gradient for the resting Ca2+ influx and open leakage calcium channel, thus resting cytoplasmic free Ca2+ concentration could be elevated. G-protein may exert an important regulation in this process.

[The effect of temperature on the behavior of aminobenzoic acid on silver surface]

SERS spectra of p-Aminobenzoic Acid (PABA) and o-Aminobenzoic Acid (OABA) absorbed on a silver surface, roughened by nitric acid, have been measured with a Renishaw Raman microprobe spectrometer(lambda = 632.8 nm) at different temperature, which ranged from 30 degrees C to -190 degrees C and from -190 degrees C to 30 degrees C. Some reversible changes in some band positions have been observed. The results indicated that if the adsorbates were enhanced by chemical mechanism and the molecules lie flat on surface, e.g. p-Aminobenzoic Acid molecule, temperature had no effect on their orientation. However, the vibrational frequencies enhanced by electromagnetic mechanism shifted as temperature changed, e.g. the vibration of NH2 in o-Aminobenzoic. The fact was that temperature had effect on the orientation of the molecules.

[Observation of biofilms inside tracheal tubes by electron microscopy and the relationship between biofilms and VAP]

OBJECTIVE

To observe the formation of biofilms inside tracheal tubes and to evaluate the effect of biofilm on the development of ventilator associated pneumonia (VAP).

METHODS

Biofilms inside tracheal tubes from intubated patients were observed by scanning electron microscopy and transmission electron microscopy, meanwhile bacteria were detected in the specimens from the lower respiratory tract and the inside of tracheal tubes.

RESULTS

76% (19/25) of inner surface of tracheal tubes was coated with a confluent amorphous matrix by scanning electron microscopy. The average duration of trach-intubation in this group [(10.7 +/- 7.9) days] was longer than that in the other group [(2.1 +/- 0.8) days] in which tracheal tubes were not coated with the confluent amorphous matrix (P < 0.05). The presence of many bacteria(14/18) within these amorphous matrix was confirmed by transmission electron microscopy. Of the sixteen tracheal tubes, eleven tubes grew the same organisms that had been isolated from the secretions of the lower respiratory tract before extubation. In some VAP patients (7/8), organisms isolated from tracheal tubes were the same organisms which were pathogenic organisms of VAP.

CONCLUSIONS

There was a close connection between the formation of bacterial BF and the long-term indwelling tracheal tubes. The presence of bacterial BF in the inner of tracheal tubes might be associated with the pathogenic organisms of VAP.

Gonadal cryopreservation in the young patient with gynaecological malignancy

For patients who are planning to have chemotherapy, radiotherapy or to undergo bilateral oophorectomy, the loss of ovarian function will result in premature ovarian menopause and loss of fertility. Embryo preservation is not an option for single women or married women because delaying treatment for at least 2 months of in-vitro fertilization cycles is inappropriate and may be life-threatening. This study reports on the indications for ovarian tissue cryobanking and the state of the art of this method in preserving fertility in women with iatrogenic premature menopause.

Distribution and epidermal growth factor receptor expression of primordial follicles in human ovarian tissue before and after cryopreservation

The freezing of ovarian tissue and the growth of immature oocytes from primordial follicles is an interesting concept in ovarian tissue transplantation and in-vitro fertilization. In this study, the morphology and distribution of primordial follicles were studied in ovarian tissue from 24 women before and after cryopreservation. Cryopreservation did not significantly change either the morphology or number per unit volume of morphologically normal follicles in frozen ovarian tissue. Primordial follicles were predominant, accounting for 78.6% and 82.6% of total follicles in fresh and frozen ovarian tissues respectively. The distribution of follicles was extremely uneven in ovarian tissue. A large variation in follicle numbers was observed in ovarian tissue samples from patient to patient, and even in the same patient, indicating that the number of follicles counted in one sample of ovarian tissue may not represent the number of follicles in other tissue samples. Ovarian tissue could be frozen in the form of strips instead of fragments for fast processing and better viability of ovarian tissue in cryopreservation. The number of follicles in ovarian tissue declined with the increasing age of the patients. An immunohistochemical study showed that immunoreactivity for the epidermal growth factor (EGF) receptor was detected in primordial follicles of adult ovarian tissue. EGF receptor staining was most intense in the oocytes of primordial follicles. Weak staining for EGF receptor was observed in some surrounding pregranulosa cells. Immunohistochemical staining for EGF receptor was also present in the stromal cells of ovarian tissue, but to a much lesser degree. There was no significant difference in the immunohistochemical staining for EGF receptor in ovarian tissue before and after cryopreservation.