Unexpected low oxygen tension of intravaginal culture

The goal of this study was to assess whether the metabolic activityof gametes or the local environment had a greater influenceon the pH, pO₂ and pCO₂ of the culture medium in the intravaginalculture (IVC) technique. The pH, pO₂ and pCO₂ of the culturemedium in four groups of intravaginal cryotubes with or withoutspermatozoa and oocytes, together with the pO₂ and pCO₂ of vaginalepithelium, were measured before and 48 h after IVC. Hermeticallyclosed cryotubes sealed in a cryoflex envelope were used throughoutSimilar results were obtained from all four groups. The pH andpCO₂ were unchanged but pO₂ significantly decreased during IVC,presumably because of equilibration with the low pO₂ (5 mmHg)and pCO₂ (49 mmHg) present in the vaginal epithelium. A secondseries of experiments was then performed with standard cultureconditions using culture medium with or without motile spermatozoain cryotubes covered with cryoflex maintained in air supplementedwith 5% CO₂. The pH, pO₂ and pCO₂ were all unchanged in allsamples. When the samples were maintained in air only, the pHincreased, pO₂ remained unchanged and pCO₂ decreased, presumablybecause of equilibration with the low pCO₂ (0.3 mmHg) presentin the air. However, when the samples were cultured under venousblood, the pH and pO2 decreased and pCO₂ increased, presumablybecause of the high pCO₂ and low pH of venous blood. Thus thepO₂ and pCO₂ of the culture medium were able to equilibratewith the local environmental gas milieu owing to the permeabilityof O₂ and CO₂ through the plastic material. IVC results in aconstant pH due to an identical pCO₂ in the vaginal epitheliumbut in a reduced pO₂ concentration due to the lower pO₂ in thevaginal epithelium.     

Prevention of post-surgical adhesion formation using aspirin in a rodent model: a preliminary report

Pelvic adhesions are one of the major factors which significantlyand adversely affect surgery outcome due to intra-and postoperativemorbidity and reduce future female fertility. Using a rodentmodel, we evaluated the efficacy of aspirin, a non-steroidalanti-inflammatory drug, in the prevention of adhesion formation.A total of 72 female Wistar rats received a standardized primarytraumatic lesion to the right uterine horn. They were randomlydivided into eight groups: group I (control) had no treatmentand group II received a single pre-operative 0.70 mg aspirin.All the succeeding groups (III-VIII) received aspirin in dosesof 0.35, 0.70, or 1.40 mg every 6 h for either 48 or 96 h inaddition to the pre-operative aspirin (0.70 mg). All animalswere killed 4 weeks later and adhesions were assessed usinga modified adhesion scoring scale. The lowest adhesion scorewas found in the group treated with 0.35 mg of aspirin for 96h, and the highest was found among the groups treated with either0.70 or 1.40 mg for 48–96 h respectively (P < 0.05).These results are in line with the hypothesis that administrationof a low dose of aspirin selectively inhibits the productionof thromboxane A₂, whereas basal prostacyclin biosynthesis ispreserved. This phenomenon might contribute to reducing postoperativeadhesion formation in a rat model. Thus, future studies intothe prevention of adhesion formation may require the additionaluse of a non-steroidal anti-inflammatory drug, for which aspirindeserves further attention, before extrapolation into humantherapy.     

Pneumoperitoneum induced pH changes in follicular and Douglas fluids during laparoscopic oocyte retrieval in humans

The effects of different insufflation media gases for pneumoperitoneumon the acidity of follicular fluid and blood acid-base balancewere studied in two groups of patients during laparoscopic oocyteretrieval. Insufflation with 100% CO₂ was compared with insufflationwith 5% CO₂ in air. End-tidal CO₂ and the acid-base status ofarterial blood, follicular and Douglas fluids were evaluated.When using 5% CO₂ in air as Insufflatlon gas, pH values andpCO₂ levels observed in the aspirated follicular (pH: 7.35 ±0.06, pCO₂: 38.8 ± 4.5 mmHg) and Douglas fluid (pH: 7.40± 0.07, pCO₂: 38.5 ± 6.2 mmHg) remained normal.With 100% CO₂ insufflation, the follicular fluid pH (7.22 ±0.07) and pCO₂ (53.1 ± 10.9 mmHg) and the Douglas fluidpH (6.99 ± 0.12) and pCO₂ (90.3 ± 18.4 mmHg) weregrossly disturbed and outside the physiological range. No differencesoccurred in pO₂ or HCO₃ levels. These data suggest that pneumoperitoneumwith 5% CO₂ in air provides more optimal environmental conditionsfor oocytes used for in-vitro fertilization. However, furtherinvestigations on large patient groups are required to demonstratewhether such environmental conditions influence the successrate of in-vitro fertilization in humans.     

Pregnancy: Oxygen promotes contraction by endothelin-1 in human umbilical artery

The influence of oxygen on the contractile response to endothelin-1in the human umbilical artery was investigated in vitro. Segmentsof human umbilical artery were suspended in organ baths to recordthe circular motor activity induced by endothelin-1 at a pO₂of 12 kPascal (kPa) or 45 kPa. Endothelin-1 induced a concentration-dependentcontraction which was significantly larger at 45 kPa O₂ comparedwith the contractile response at 12 kPa O₂.     

Hypothermic preservation of lung allograft inhibits cytokine-induced chemoattractant-1, endothelial leucocyte adhesion molecule, vascular cell adhesion molecule-1 and intracellular adhesion molecule-1 expression

Organ dysfunction is a major clinical problem after lung transplantation. Prolonged cold ischaemia and reperfusion injury are believed to play a central role in this complication. The influence of cold preservation on subsequent warm reperfusion was studied in an isolated, ventilated and perfused rat lung. Rat lungs were flushed with cold Perfadex-solution and stored at 4 degrees C for different time periods. Thereafter lungs were perfused and ventilated for up to 3 h. Physiological parameters, production of inflammatory mediators and leucocyte infiltration were measured before and after perfusion. Lungs subjected to a cold ischaemia time of up to 6 h showed stable physiological conditions when perfused for 3 h. However, cold-ischaemia time beyond 6 h resulted in profound tissue oedema, thereby impairing ventilation and perfusion. Warm reperfusion and ventilation per se induced a strong inflammatory response, as demonstrated by a significant up-regulation of chemokines and adhesion molecules (cytokine-induced chemoattractant-1, intracellular adhesion molecule and endothelial leucocyte adhesion molecule), accompanied by enhanced leucocyte infiltration. Although the up-regulation of inflammatory mediators was blunted in lungs that were subjected to cold ischaemia, this did not influence leucocyte infiltration. In fact, cold ischaemia time correlated with leucocyte sequestration. Although cold preservation inhibits the expression of inflammatory mediators it does not affect leucocyte sequestration during warm reperfusion. Cold preservation might cause impairment of the endothelial barrier function, as evidenced by tissue oedema and profound leucocyte infiltration.     

Immunology: Distribution of cell adhesion molecules on CD56++, CD3-, CD16- large granular lymphocytes and endothelial cells in first-trimester human decidua

Human decidua exhibits a unique infiltrate of large granularlymphocytes (LGL) with a natural killer (NK) cell phenotype(CD56++, CD16–, CD3–). The mechanisms underlyingthe binding of circulating LGL to vascular endothelium in thedecidua and their migration into the decidual stroma were investigatedimmunohistochemically in first-trimester decidua with antibodiesagainst endothelial adhesion molecules and their counter-receptorson leukocytes. Decidual and peripheral blood LGL were also investigatedby flow cytometry. In the immunohistochemical investigations,moderate to large numbers of lymphoid cells in the decidua werefound to express the ₄ and _L integrin subunits, platelet endothelialcell adhesion molecule (PECAM) and intercellular adhesion molecule-1(ICAM-1). PECAM and ICAM-1 were found on the endothelium oflarge numbers of decidual blood vessels of all types. Vascularcell adhesion molecule (VCAM), however, was found on the endotheliumof only small to moderate numbers of arterioles and venulesand a few capillaries, the latter being the main site of migrationof leukocytes into the stroma. Weak staining for endothelialleukocyte adhesion molecule (ELAM) was seen only in a moderatenumber of blood vessels. Flow cytometry revealed expressionof the _L integrin subunit by 72 ± 10% and 97 ±3% of decidual and peripheral blood CD56+ LGL, respectively,of the 4 integrin subunit by 85 ± 7% and 90 ±5%, of PECAM by 40 ± 12% and 30 ± 15%, and ofICAM-1 by 22 ± 10% and 1 ± 1%. These findingssuggest that interaction between the integrin _2L and ICAM-1is the more important mechanism of binding to endothelium inthe migration of CD56+ LGL out of the peripheral blood intothe decidua.     

Surgery: Experimental model for neoangiogenesis in adhesion formation

This study presents an animal model for the observation of adhesionformation, from a vascular viewpoint. In 60 Wistar rats, a 4cm midline incision was made and a 0.5 cm square piece of silastic0.2 mm thick was fixed on the right side of the peritoneum withtwo separate angular stitches of nylon 9/0. The rats were randomizedin six groups of 10 animals and were operated on again on days2, 4, 6, 8, 10 and 12 respectively. Biopsies for scanning electronmicroscopy were obtained by resecting a 2x2 cm square of parietalperitoneum around and covering the silastic patch. Foreign bodyreaction induced by the silastic patch and ischaemia causedby stitching are the stimuli for adhesion formation. The resultsshowed a gradual progression in the type and tenacity of adhesionformation. The maximal degree of peritoneal reactive angiogenesiswas noted between days 8 and 12, together with a decrease anda redistribution in the extent of adhesions. In the early stages,vascularization is part of the organization of adhesions whiletheir extent is limited. Two parallel mechanisms take part intrauma healing: while omentoparietal adhesions are vascularized,new peritoneal tissue with its vascular network develops andcovers the silastic surface and the traumatized area. This theoryis supported by the presence of fibroblasts differentiatinginto mesothelial cells on day 8. Theoretically, a valid treatmentin preventing adhesion formation should increase the peritonealneoangiogenesis and the repair of peritoneal lesions, but atthe same time prevent the vascularization of adhesions. Thepresent model offers the possibility of testing the effect ofany treatment or device for preventing postoperative adhesionsin a relatively short time.     

Effect of temperature upon adhesion formation in a laparoscopic mouse model

BACKGROUND: Pneumoperitoneum can be a cofactor in adhesion formation. Pneumoperitoneum with non-humidified gas causes desiccation in the peritoneal cavity which decreases temperature. The effect of desiccation upon adhesion formation is widely accepted. The specific effect of the associated cooling upon adhesion formation remains unexplored, and was addressed specifically in our laparoscopic mouse model. METHODS: Adhesions were induced during laparoscopy and scored after 7 days during laparotomy. Pneumoperitoneum was performed using CO2 or CO2 with oxygen with or without humidification. Animals were placed at different environmental temperatures to modulate body and intraperitoneal temperature. RESULTS: Anaesthesia, environment with a lower temperature and pneumoperitoneum all independently decrease body temperature. A decrease in body temperature decreases adhesion formation (P=0.004). Therefore, at 37 degrees C, pneumoperitoneum-enhanced adhesion formation is more important than at room temperature (P=0.04). As was observed at room temperature, adhesion formation at 37 degrees C increases with the duration (P=0.01) of pneumoperitoneum and decreases with the addition of 3% of oxygen (P=0.03). CONCLUSIONS: Hypothermia reduces pneumoperitoneum-enhanced adhesion formation, which supports hypoxia as a driving mechanism, since hypothermia decreases the toxic effects of hypoxia and of the ischaemia-reperfusion process. These data could open up new possibilities for adhesion prevention in laparoscopic surgery.     

Hypoxaemia induced by CO(2) or helium pneumoperitoneum is a co-factor in adhesion formation in rabbits

A prospective randomized trial in a rabbit model was performed to test the hypothesis that the increase in adhesion formation following prolonged pneumoperitoneum is mediated by peritoneal hypoxaemia. Laparoscopic standardized opposing lesions were performed in uterine horns and pelvic sidewalls by bipolar coagulation and CO(2) laser in six groups of eight animals. Pure CO(2) or helium pneumoperitoneum was used for 10 (groups I and IV) or 45 min (groups II and V) to confirm the effect of duration of pneumoperitoneum and 96% of CO(2) or helium with 4% of oxygen (group III and VI) for 45 min to assess the effect of the addition of oxygen. After 7 days, adhesion formation was scored by laparoscopy. By two-way analysis of variance, total, extent, type and tenacity of adhesion scores increased (P = 0.0003, P = 0.0004, P = 0.0004 and P = 0.004) with increasing duration of pneumoperitoneum and decreased (P = 0.02, P = 0.03, P = 0.01 and P = 0.05) with the addition of oxygen. No differences were found between CO(2) and helium. In conclusion these data confirm the effect of pneumoperitoneum upon adhesions and demonstrate its reduction by oxygen, strongly suggesting that the main cause of adhesion formation is the relatively superficial hypoxaemia produced by the pneumoperitoneum.     

Reduction of postoperative adhesion formation after laparoscopic ovarian cystectomy

The purpose of this randomized, open-label study was to assessthe efficacy of the product Interceed absorbable adhesion barrierin the prevention of adhesion formation on the ovary after laparoscopicovarian cystectomy. A total of 25 patients requiring laparoscopicbilateral ovarian cystectomy were enrolled into this study.After removal of ovarian cysts, peri-adnexal adhesions, andperitoneal irrigants, and the attainment of meticulous haemostasis,the random assignment of one ovary for wrapping with Interceedwas revealed to the surgeon. The other ovary served as the untreatedcontrol. A follow-up laparoscopy was performed 8–30 weeksafter the initial procedure in 17 patients. Significantly feweradhesions formed at the Interceed treated ovaries compared withthe control (untreated) ovaries (P < 0.05). In terms of adhesion-freeoutcome, 76% (13/17) of Interceed treated ovaries and 35% (6/17)of control ovaries were free of adhesions. A significant reductionwas observed in the area of the sutured ovaries involved withadhesions when Interceed (6%) was used, compared with controls(20%). The reduction of adhesion formation was not related tothe size of the cysts at the initial procedure. No adverse eventswere reported by any patient during the study. In conclusion,Interceed was found to be safe and effective in reducing theincidence of postoperative adhesion formation in patients undergoinglaparoscopic ovarian cystectomy.     

The effect of intra-abdominal pressure on the generation of 8-iso prostaglandin F2alpha during laparoscopy in rabbits

BACKGROUND: Carbon dioxide pneumoperitoneum induces peritoneal oxidative stress. The aim of this study was to verify the effect of intra-abdominal pressure on oxidative stress in the peritoneum and on post-operative adhesion formation. METHODS: Forty-one rabbits underwent laparoscopic surgery: either gasless, or with CO(2)-pneumoperitoneum at pressures of 5, 10 or 15 mmHg. Serial parietal peritoneal biopsies were taken at various time-points: immediately after reaching the abdominal cavity, 30, 60, 90 and 120 min afterwards, and 15 min after abdominal desufflation. 8-iso prostaglandin F(2alpha) (8-iso PGF(2alpha)), a marker of oxidative stresss, was assayed by enzyme immunoassay and adhesion formation was scored by second-look laparoscopy on day 14. RESULTS: The gasless group showed no significant changes in 8-iso PGF(2alpha). Conversely, significant changes occurred in CO(2)-pneumoperitoneum in a time- and pressure-dependent manner. Adhesions developed only in the CO(2)-pneumoperitoneum groups, and total adhesion score was correlated with the amount of CO(2) insufflated and intra-abdominal pressure, but not with 8-iso PGF(2alpha), which was correlated with intra-abdominal pressure. CONCLUSION: Intra-abdominal pressure increased 8-iso PGF(2alpha) in the parietal peritoneum in a graded fashion, whilst gasless laparoscopy had no impact. It also influenced the frequency and severity of adhesion formation, but no causal link was found between 8-iso PGF(2alpha) and post-operative adhesion formation.     

Evaluation of a sprayable polyethylene glycol adhesion barrier in a porcine efficacy model.

BACKGROUND: The formation of adhesions following pelvic surgery remains one of the leading causes of infertility, small bowel obstruction and re-operation for pelvic pain. A novel hydrophilic polyethylene glycol based adhesion barrier (SprayGel) is formed by simultaneously spraying two liquid precursors onto surgical sites. The liquids polymerize to form a gel that effectively coats and adheres to tissue. After about 5 days, the hydrogel layer is absorbed and subsequently undergoes renal clearance. It is believed that the presence of such a barrier would inhibit the formation of adhesions following surgical insult. METHODS: A porcine adhesion model was developed wherein bilateral uterine horn transection and re-anastomosis, along with peritoneal side wall excision was performed via laparotomy. In each animal (n = 10, including the pilot study) one pelvic side wall was treated with adhesion barrier, while the contralateral side remained untreated. RESULTS: At second look laparoscopy, 90% of the untreated sites had adhesions, compared with 30% of the treated sites (P = 0.006). Also observed were statistically significant reductions in the adhesion extent (P = 0.029) and adhesion severity scores (P = 0.023) at the treated sites. However, if the pilot study was excluded (n = 8) the differences obtained were no longer significant. CONCLUSIONS: Polyethylene glycol (SprayGel) merits further investigation as an effective barrier to the formation of post-operative adhesions in this porcine model.     

Adhesion formation in intubated rabbits increases with high insufflation pressure during endoscopic surgery

The aim of the study was to test the hypothesis that the increase in adhesion formation by CO(2) pneumoperitoneum is caused by mesothelial hypoxaemia. Therefore the effect of the intra-abdominal pressure together with the flow rate upon adhesion formation was evaluated in rabbits following laser and bipolar lesions during endoscopic surgery using humidified CO(2) at 35 +/- 1 degrees C. The intra-abdominal pressure and flow rate were 5 mmHg and 1 l/min in group 1 (n = 5), 5 mmHg and 10 l/min in group 2 (n = 4), 20 mmHg and 1 l/min in group 3 (n = 5) and 20 mmHg and 10 l/min in group 4 (n = 4) respectively. A rapid and reliable intubation method for rabbits was developed to permit high insufflation pressure. By two-way analysis of variance, total adhesion scores following a laser lesion increased with flow rate (P = 0.0003) and insufflation pressure (P = 0.002). Total adhesion scores of bipolar lesions increased with pressure (P = 0.02) but not with flow rate (P = 0.1). The total adhesion scores of laser and bipolar lesions together increased with flow rate (P = 0.005) and with insufflation pressure (P = 0.004). There was no statistical interaction between flow rate and insufflation pressure. In conclusion, the insufflation pressure in endoscopic surgery with CO(2) pneumoperitoneum is a co-factor in adhesion formation, together with desiccation.     

Cerebellum pO2 and the sleep-waking cycle in cats.

Cats were chronically implanted with oxygen cathodes in cerebellar nuclei and cortex. Eye movements, neck muscles activity, electrocorticogram and ponto-geniculo-occipital spikes were recorded to monitor the animal behavior. In every experimental session the oxygen dependence of the cathode was tested by changing the oxygen concentration of the inhaled gases. During paradoxical sleep a sudden increase in the amplitude of the pO₂ oscillations was observed in cortical and subcortical cerebellar loci. No relationship could be established with any movement or other phasic paradoxical sleep phenomena. This pO₂ oscillating response made of the cerebellum a part of a larger pO₂ sleep system that runs rostrally in the basal brain. In waking and slow sleep conditions no such response was demonstrated but an oscillatory pO₂ pattern was described. It is postulated that these variations are due to a local increase of neuronal activity. During very active wakefulness a similar, but diffusely distributed response, was detected.     

The impact of peritoneal trauma on intra-abdominal fibrinolytic activity, adhesion formation and early embryonic development in a rabbit longitudinal model

Intra-abdominal adhesions may interfere with fertility following gynaecological surgery and injury to the peritoneum plays a central role in the pathogenesis. Tissue plasminogen activator and its antagonists play a pivotal role in the intra-abdominal balance between fibrinolysis and adhesion formation. This process may be cycle-dependent in women. In order to establish the impact of the fibrinolytic activity on adhesion formation after a standardized trauma, a rabbit longitudinal model was developed, which allowed the study of possible differences between the periods before and after ovulation. The influence of extra-genital adhesions on early embryonic development was investigated. No cycle-dependent changes in fibrinolytic activity of the peritoneal fluid (PF) or of the serum could be demonstrated. No correlation was found between post-operative adhesion formation and the fibrinolytic activity during surgery. Three weeks after surgery, a significant increase in fibrinolytic activity of the PF was observed. The rank order of sampling is suggested to account for these differences. Extra-genital adhesions did not markedly influence ovulation, ovum pick-up and fertilization in this hormonally controlled rabbit model.     

The effect of RU486 administered during the proliferative and secretory phase of the cycle on the bleeding pattern, hormonal parameters and the endometrium

Seventeen healthy women aged 24–45 years with regularmenstrual periods, proven fertility and not using steroidalcontraceptives or IUD were recruited for the study. The volunteerswere followed during one control, one treatment and one follow-upcycle. Daily morning urine samples were obtained during thecontrol and the treatment cycle. The samples were analysed withregard to pregnanediol glucuronide (P₂-G), oestrone glucuronide(E₁-G), oestradiol (E₂), progesterone (P₄), LH and creatinine.During the entire 3-month study the subjects kept a record ofuterine bleeding and side effects. The subjects received 50mg RU486 daily either on cycle days 7–10 (n = 7) or oncycle days 20–23 (n = 10). An endometrial biopsy was takenon cycle day 10 in the first group and on cycle days 21–28in the second group of patients. Treatment during the proliferativephase caused significant prolongation of the cycle length dueto a delay of the oestrogen and LH surge. However, once theoestrogen concentration started to increase, the remaining partof the cycle was normal. The length of the follow-up cycle wassimilar to that of the control cycle. The morphology of theendometrium did not differ from control samples taken from untreatedwomen at the same time of the cycle. All ovulating women (n= 9) treated in the mid-luteal phase started to bleed on the3rd to 4th day of the treatment. In four of these women thebleeding was scanty and followed by a menstrual-like bleedingat expected time, while in the remaining five volunteers thetreatment bleeding was heavier and not followed by a new bleedinguntil a month later. The duration of the secretory phase was16.5 ± 1.3 days in women with two bleeding episodes and11.8 ± 1.9 days in women with one bleeding episode (P< 0.05). The hormonal parameters were similar in both groupsup to the start of the treatment. In the patients with one bleedingepisode, the treatment was associated with a reduction in progesteroneconcentration, while in the patients with two bleeding episodesthe progesterone concentration remained elevated until the secondbleeding episode. Light microscopic examination of the endometriumrevealed unique changes in the endometrial morphology. The resultsindicate that RU486 acts mainly on the endometrium but a director indirect effect on the corpus luteum cannot be excluded.The age of the corpus luteum may be of importance for its susceptibilityto RU486 treatment.     

The effect of prostaglandins and aspirin--an inhibitor of prostaglandin synthesis--on adhesion formation in rats

The effect of intraperitoneal application of prostaglandins E2 and F2 alpha and of aspirin, a non-steroidal anti-inflammatory drug, on the formation of intraperitoneal adhesions was investigated in rats, in view of the main role of the body's reaction in adhesion formation. Intraperitoneal adhesions were induced by inflicting uniform trauma to the uterine serosa. It was demonstrated that prostaglandin E2 may increase adhesion formation and that intraperitoneal aspirin is able to inhibit its formation.     

Sperm motility and kinetics of dynein ATPase in astheno- and normozoospermic samples after stimulation with adenosine and its analogues

We tested the effects of adenosine and 2-deoxyadenosine on theactivation of human spermatozoa. In the asthenozoospermic groupof patients adenosine produces an increase in sperm motilityfrom 33.3 ± 2.1% to 42.1 ± 3.4%, progressive motilityfrom 22.5 ± 1.3% to 28.6 ± 1.7% and forward progressionrating from 2.1 ± 0.2% to 2.8 ± 0.1%. 2-Deoxyadenosinestimulated asthenozoospermic samples to a greater degree thanadenosine. Sperm motility rose to 48.9 ± 3.4%, progressivemotility to 32.1± 3.4% and forward progression ratingto 3.0 ± 0.1% following stimulation with 2-deoxy-adenosine.The kinetic parameters and basic characteristics of dynein ATPasewere determined. The maximum activity of dynein ATPase, V_max,was significantly different (P < 0.001) for asthenozoospermicand normozoospermic samples: 6.46 ± 2.1 nmol P_i/mg/minand 16.99 ± 3.7 nmol P_i/mg/min respectively. However,the enzyme affinity for ATP was not different. Stimulation ofasthenozoospermic samples with adenosine and 2-deoxyadenosinecaused an increase of V_max (70–90% and 90–110% respectively)and no significant change in K_M was observed. In order to blockthe nucleoside transporter and to eliminate the action of adenosineinside the cell, dipyridamole was used but the effects of adenosinewere not neutralized. 5’-(N-ethylcarboxy-amido)-adenosineshowed effects similar to those of adenosine, even when appliedin 1µM concentration. These results indicate that adenosineand its analogues stimulate sperm motility and activity of dyneinATPase, most probably via A₂ receptors.     

The expression of {alpha}v and {beta}3 integrin subunits in the normal human Fallopian tube epithelium suggests the occurrence of a tubal implantation window

The co-expression of ₁ß₁, ₄ß₁ and _vß₃integrins in the human endometrium coincides with the implantationwindow. The _vß₃ integrin is expressed in the apicalsurface of the luminal epithelium and may serve to anchor trophoblastcells in the adhesion phase of implantation. Using immunohistochemistry,we compared the expression of _v, ₁, ₄ and ß₃ integrinsubunits in samples of normal human Fallopian tube and endometriumobtained from five women in the non-receptive period (lutealphase days 2–4) and from another five women in the receptiveperiod (luteal phase days 6–8). The staining was quantifiedvisually on a scale of 0 to ++, according to the intensity anddensity of stained cells. The _v subunit is expressed in theFallopian tube epithelium during both periods in a pericellulardistribution. The ß₃ subunit is also expressed inthe same location, but it is up-regulated during the periodof endometrial receptivity. The other subunits are expressedin localizations which are not relevant to trophoblast adhesionand exhibit little or no difference in the level of expressionbetween the non-receptive and receptive periods. Based on theseresults we postulate that the expression of the ß₃subunit in the human tubal epithelium is under the same systemiccontrolling signals as in the endometrium and that the normaltubal epithelium may have an implantation window, at about thesame time as the endometrium, that affords the opportunity fortrophoblast attachment should a 5–7 day embryo be undulyretained in the tube.     

Role of focal adhesion kinase (FAK) in renal ischaemia and reperfusion

Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, plays important roles in cell migration, cell proliferation and cell survival. Because these processes participate in the restoration of tubular integrity in renal ischaemia and reperfusion, FAK expression and phosphorylation at Tyr-397, the latter indicative of its activity, were examined in the different kidney zones by Western blot analysis and immunohistochemistry. Expression and phosphorylation of FAK were also studied in Madin-Darby canine kidney (MDCK) and medullary thick ascending limb (mTAL) cells after ATP depletion and repletion. In control rat kidneys, FAK expression in outer and inner medulla exceeded that in cortex, and phosphorylation of FAK at Tyr-397 was most pronounced in the inner medulla. Although this expression pattern was not affected by 20 (40, 60)-min ischaemia and 20 (40, 60)-min ischaemia followed by 60-min or 24-h reperfusion, FAK phosphorylation was significantly reduced in all kidney zones immediately after ischaemia, but increased during reperfusion, exceeding control values in the outer and inner medulla. ATP depletion and repletion of MDCK and mTAL cells were associated with a decrease in FAK phosphorylation during ATP depletion, followed by an increase during repletion. Rephosphorylation of FAK after ATP repletion was enhanced by N-acetylcysteine, a reactive oxygen species scavenger. ATP depletion disrupted focal adhesions in MDCK cells. Their reformation after ATP repletion paralleled the increase in FAK phosphorylation. These findings suggest an essential role for FAK-signalling during renal ischaemia and early reperfusion.