Functional performance of a bi-layered chitosan-nano-hydroxyapatite osteochondral scaffold: a pre-clinical in vitro tribological study

Osteochondral grafts are used for repair of focal osteochondral lesions. Autologous grafts are the gold standard treatment; however, limited graft availability and donor site morbidity restrict use. Therefore, there is a clinical need for different graft sources/materials which replicate natural cartilage function. Chitosan has been proposed for this application. The aim of this study was to assess the biomechanics and biotribology of a bioresorbable chitosan/chitosan-nano-hydroxyapatite osteochondral construct (OCC), implanted in an in vitro porcine knee experimental simulation model. The OCC implanted in different surgical positions (flush, proud and inverted) was compared to predicate grafts in current clinical use and a positive control consisting of a stainless steel graft implanted proud of the cartilage surface. After 3 h (10 800 cycles) wear simulation under a walking gait, subsidence occurred in all OCC samples irrespective of surgical positioning, but with no apparent loss of material and low meniscus wear. Half the predicate grafts exhibited delamination and scratching of the cartilage surfaces. No graft subsidence occurred in the positive controls but wear and deformation of the meniscus were apparent. Implanting a new chitosan-based OCC either optimally (flush), inverted or proud of the cartilage surface resulted in minimal wear, damage and deformation of the meniscus.

Development and in vitro assessment of a bi-layered chitosan-nano-hydroxyapatite osteochondral scaffold

An innovative approach was developed to engineer a multi-layered chitosan scaffold for osteochondral defect repair. A combination of freeze drying and porogen-leaching out methods produced a porous, bioresorbable scaffold with a distinct gradient of pore size (mean = 160-275 μm). Incorporation of 70 wt% nano-hydroxyapatite (nHA) provided additional strength to the bone-like layer. The scaffold showed instantaneous mechanical recovery under compressive loading and did not delaminate under tensile loading. The scaffold supported the attachment and proliferation of human mesenchymal stem cells (MSCs), with typical adherent cell morphology found on the bone layer compared to a rounded cell morphology on the chondrogenic layer. Osteogenic and chondrogenic differentiation of MSCs preferentially occurred in selected layers of the scaffold in vitro, driven by the distinct pore gradient and material composition. This scaffold is a suitable candidate for minimally invasive arthroscopic delivery in the clinic with potential to regenerate damaged cartilage and bone.

Diazepam induced sleep spindle increase correlates with cognitive recovery in a child with epileptic encephalopathy

BACKGROUND

Continuous spike and wave of sleep with encephalopathy (CSWS) is a rare and severe developmental electroclinical epileptic encephalopathy characterized by seizures, abundant sleep activated interictal epileptiform discharges, and cognitive regression or deceleration of expected cognitive growth. The cause of the cognitive symptoms is unknown, and efforts to link epileptiform activity to cognitive function have been unrevealing. Converging lines of evidence implicate thalamocortical circuits in these disorders. Sleep spindles are generated and propagated by the same thalamocortical circuits that can generate spikes and, in healthy sleep, support memory consolidation. As such, sleep spindle deficits may provide a physiologically relevant mechanistic biomarker for cognitive dysfunction in epileptic encephalopathies.

CASE PRESENTATION

We describe the longitudinal course of a child with CSWS with initial cognitive regression followed by dramatic cognitive improvement after treatment. Using validated automated detection algorithms, we analyzed electroencephalograms for epileptiform discharges and sleep spindles alongside contemporaneous neuropsychological evaluations over the course of the patient's disease. We found that sleep spindles increased dramatically with high-dose diazepam treatment, corresponding with marked improvements in cognitive performance. We also found that the sleep spindle rate was anticorrelated to spike rate, consistent with a competitively shared underlying thalamocortical circuitry.

CONCLUSIONS

Epileptic encephalopathies are challenging electroclinical syndromes characterized by combined seizures and a deceleration or regression in cognitive skills over childhood. This report identifies thalamocortical circuit dysfunction in a case of epileptic encephalopathy and motivates future investigations of sleep spindles as a biomarker of cognitive function and a potential therapeutic target in this challenging disease.

Investigating the feasibility of spatially offset Raman spectroscopy for in-vivo monitoring of bone healing in rat calvarial defect models

A wide range of biomaterials and tissue-engineered scaffolds are being investigated to support and stimulate bone healing in animal models. Using phantoms and rat cadavers, we investigated the feasibility of using spatially offset Raman spectroscopy (SORS) to monitor changes in collagen concentration at levels similar to those expected to occur in vivo during bone regeneration (0-0.84 g/cm³ ). A partial least squares (PLS) regression model was developed to quantify collagen concentration in plugs consisting of mixtures or collagen and hydroxyapatite (predictive power of ±0.16 g/cm³ ). The PLS model was then applied on SORS spectra acquired from rat cadavers after implanting the collagen: hydroxyapatite plugs in drilled skull defects. The PLS model successfully predicting the profile of collagen concentration, but with an increased predictive error of ±0.30 g/cm³ . These results demonstrate the potential of SORS to quantify collagen concentrations, in the range relevant to those occurring during new bone formation.

Spatially-offset Raman spectroscopy for monitoring mineralization of bone tissue engineering scaffolds: feasibility study based on phantom samples

Using phantom samples, we investigated the feasibility of spatially-offset Raman spectroscopy (SORS) as a tool for monitoring non-invasively the mineralization of bone tissue engineering scaffold in-vivo. The phantom samples consisted of 3D-printed scaffolds of poly-caprolactone (PCL) and hydroxyapatite (HA) blends, with varying concentrations of HA, to mimic the mineralisation process. The scaffolds were covered by a 4 mm layer of skin to simulate the real in-vivo measurement conditions. At a concentration of HA approximately 1/3 that of bone (~0.6 g/cm³), the characteristic Raman band of HA (960 cm^-1) was detectable when the PCL:HA layer was located at 4 mm depth within the scaffold (i.e. 8 mm below the skin surface). For the layers of the PCL:HA immediately under the skin (i.e. top of the scaffold), the detection limit of HA was 0.18 g/cm³, which is approximately one order of magnitude lower than that of bone. Similar results were also found for the phantoms simulating uniform and inward gradual mineralisation of the scaffold, indicating the suitability of SORS to detect early stages of mineralisation. Nevertheless, the results also show that the contribution of the materials surrounding the scaffold can be significant and methods for subtraction need to be investigated in the future. In conclusion, these results indicate that spatially-offset Raman spectroscopy is a promising technique for in-vivo longitudinal monitoring scaffold mineralization and bone re-growth.

Management of thyroid eye disease in the United Kingdom: A multi-centre thyroid eye disease audit

This article aims to provide baseline data and highlight any major deficiencies in the current level of care provided for adult patients with thyroid eye disease (TED). We undertook a prospective, nonrandomized cross-sectional multicenter observational study. During a 3-month period June-August 2014, consecutive adult patients with TED who presented to nominated specialist eye clinics in the United Kingdom, completed a standardized questionnaire. Main outcome measures were: demographics, time from diagnosis to referral to tertiary centre, time from referral to review in specialist eye clinic, management of thyroid dysfunction, radioiodine and provision of steroid prophylaxis, smoking, and TED classification. 91 patients (mean age 47.88 years) were included. Female-to-male ratio was 6:1. Mean time since first symptoms of TED = 27.92 (73.71) months; from first visit to any doctor with symptoms to diagnosis = 9.37 (26.03) months; from hyperthyroidism diagnosis to euthyroidism 12.45 (16.81) months. First, 13% had received radioiodine. All those with active TED received prophylactic steroids. Seven patients who received radioiodine and did not have TED at the time went on to develop it. Then, 60% patients were current or ex-smokers. 63% current smokers had been offered smoking cessation advice. 65% patients had active TED; 4% had sight-threatening TED. A large proportion of patients (54%) were unaware of their thyroid status. Not enough patients are being provided with smoking cessation advice and information on the impact of smoking on TED and control of thyroid function.

The impact of communicating information about air pollution events on public health

Short-term exposure to air pollution has been associated with exacerbation of asthma and chronic obstructive pulmonary disease (COPD). This study investigated the relationship between emergency hospital admissions for asthma, COPD and episodes of poor air quality in an English city (Southampton) from 2008-2013. The city's council provides a forecasting service for poor air quality to individuals with respiratory disease to reduce preventable admissions to hospital and this has been evaluated. Trends in nitrogen dioxide, ozone and particulate matter concentrations were related to hospital admissions data using regression analysis. The impacts of air quality on emergency admissions were quantified using the relative risks associated with each pollutant. Seasonal and weekly trends were apparent for both air pollution and hospital admissions, although there was a weak relationship between the two. The air quality forecasting service proved ineffective at reducing hospital admissions. Improvements to the health forecasting service are necessary to protect the health of susceptible individuals, as there is likely to be an increasing need for such services in the future.

Is Clostridium difficile associated with the '4C' antibiotics? A retrospective observational study in diabetic foot ulcer patients

AIMS

Clostridium difficile is an anaerobic cytotoxin-producing bacterium that can cause infectious diarrhoea, pseudomembranous colitis and toxic megacolon. The major risk factors for developing C. difficile infection include recent or current antimicrobial use, diabetes, age over 65, proton pump inhibitor use, immunosuppression and previous infection with C. difficile. Most diabetic foot ulcers are polymicrobial.

METHODS

As a result guidelines advise treatment with broad spectrum antibiotics which include the '4C's' (clindamycin, cephalosporins, co-amoxiclav and ciprofloxacin) which are associated with a higher risk of C. difficile infection. Retrospective observational data (June 2008 to January 2012) for the diabetes foot ulcers were gathered from the Diabetes/Podiatry Clinic database in NHS Ayrshire and Arran and cross-matched with the NHS Ayrshire and Arran Microbiology database. There were 111 patients with mean age 59 years (range 24-94 years), 33 type 1 patients, 78 type 2 patients, mean duration of diabetes 16 years (6 months-37 years) and mean HbA1c 67 mmol/mol (54-108 mmol/mol) [8.3% (7.1-12%)].

RESULTS

The total number of days antimicrobials prescribed for all patients was 7938 (mean number of antimicrobial days per patient = 71.5 days). There was one case of C. difficile infection of 111 patients giving an incidence of 1.25 cases per 10,000 patient-days of antibiotics/1 case per 209 foot ulcers.

CONCLUSIONS

Large doses, numbers and greater duration of antibiotic therapy all result in a greater degree of normal gut flora depletion. It is possible that the alterations in gut flora in diabetic foot ulcer patients protect them from antibiotic-induced C. difficile overgrowth.

The Intercostal NMJ Assay: a new alternative to the conventional LD50 assay for the determination of the therapeutic potency of botulinum toxin preparations

Therapeutic botulinum neurotoxin type A preparations have found an increasing number of clinical uses for a large variety of neuromuscular disorders and dermatological conditions. The accurate determination of potency in the clinical application of botulinum toxins is critical to ensuring clinical efficacy and safety, and is currently achieved by using a lethal dose (LD50) assay in mice. Ethical concerns and operational constraints associated with this assay have prompted the development of alternative assay systems that could potentially lead to its replacement. As one such alternative, we describe the development and evaluation of a novel ex vivo assay (the Intercostal Neuromuscular Junction [NMJ] Assay), which uses substantially fewer animals and addresses ethical concerns associated with the LD50 assay. The assay records the decay of force from electrically-stimulated muscle tissue sections in response to the toxin, and thus combines the important mechanisms of receptor binding, translocation, and the enzymatic action of the toxin molecule. Toxin application leads to a time-related and dose-related reduction in contractile force. A regression model describing the relationship between the applied dose and force decay was determined statistically, and was successfully tested as able to correctly predict the potency of an unknown sample. The tissue sections used were found to be highly reproducible, as determined through the innervation pattern and the localisation of NMJs in situ. Furthermore, the efficacy of the assay protocol to successfully deliver the test sample to the cellular target sites, was critically assessed by using molecular tracer molecules.

Grain sorghum is a viable feedstock for ethanol production

Sorghum is a major cereal crop in the USA. However, sorghum has been underutilized as a renewable feedstock for bioenergy. The goal of this research was to improve the bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus was to understand the relationship among "genetics-structure-function-conversion" and the key factors impacting ethanol production, as well as to develop an energy life cycle analysis model (ELCAM) to quantify and prioritize the saving potential from factors identified in this research. Genetic lines with extremely high and low ethanol fermentation efficiency and some specific attributes that may be manipulated to improve the bioconversion rate of sorghum were identified. In general, ethanol yield increased as starch content increased. However, no linear relationship between starch content and fermentation efficiency was found. Key factors affecting the ethanol fermentation efficiency of sorghum include protein digestibility, level of extractable proteins, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylose to amylopectin, and formation of amylose-lipid complexes in the mash. A platform ELCAM with a base case showed a positive net energy value (NEV) = 25,500 Btu/gal EtOH. ELCAM cases were used to identify factors that most impact sorghum use. For example, a yield increase of 40 bu/ac resulted in NEV increasing from 7 million to 12 million Btu/ac. An 8% increase in starch provided an incremental 1.2 million Btu/ac.

Regulation of cyclin D2 and the cyclin D2 promoter by protein kinase A and CREB in lymphocytes

Lymphocyte proliferation is key to the regulation of the immune system. Cyclin D2 is the first cell cycle protein induced following stimulation through the T-cell receptor, the B-cell receptor or cytokines. The promoter of this cyclin integrates a diverse range of signals. Through investigating the regulation of this promoter by interleukin-2 and phosphatidylinositol 3-kinase, we have identified a role for the transcription factor CREB, cAMP response element-binding protein. Mutation of the CREB-binding site reduced cyclin D2 promoter activity 5-10-fold. CREB-1 is phosphorylated at serine 133, a critical site for activity, in both T cells and Epstein-Barr virus immortalized B cells. The introduction of an S133A mutant of CREB-1 reduces IL-2 induction of cyclin D2 promoter activity, demonstrating a role for this phosphorylation site in promoter activity. Two inhibitors of protein kinase A reduce lymphocyte proliferation and CREB-1 phosphorylation. This study demonstrates that the cyclin D2 promoter is capable of being regulated by PI3K and CREB and identifies CREB-1 and protein kinase A as potential targets for altering lymphocyte proliferation.

Matrix metalloproteinases 2 and 9 (gelatinases A and B) expression in malignant mesothelioma and benign pleura

Matrix metalloproteinases (MMPs), in particular the gelatinases (MMP-2 and -9), play a significant role in tumour invasion and angiogenesis. The expression and activities of MMPs have not been characterised in malignant mesothelioma (MM) tumour samples. In a prospective study, gelatinase activity was evaluated in homogenised supernatants of snap frozen MM (n=35), inflamed pleura (IP, n=12) and uninflammed pleura (UP, n=14) tissue specimens by semiquantitative gelatin zymography. Matrix metalloproteinases were correlated with clinicopathological factors and with survival using Kaplan-Meier and Cox proportional hazard models. In MM, pro- and active MMP-2 levels were significantly greater than for MMP-9 (P=0.006, P<0.001). Active MMP-2 was significantly greater in MM than in UP (P=0.04). MMP-2 activity was equivalent between IP and MM, but both pro- and active MMP-9 activities were greater in IP (P=0.02, P=0.009). While there were trends towards poor survival with increasing total and pro-MMP-2 activity (P=0.08) in univariate analysis, they were both independent poor prognostic factors in multivariate analysis in conjunction with weight loss (pro-MMP-2 P=0.03, total MMP-2 P=0.04). Total and pro-MMP-2 also contributed to the Cancer and Leukemia Group B prognostic groups. MMP-9 activities were not prognostic. Matrix metalloproteinases, and in particular MMP-2, the most abundant gelatinase, may play an important role in MM tumour growth and metastasis. Agents that reduce MMP synthesis and/or activity may have a role to play in the management of MM.

Normal human keratocyte density and corneal thickness measurement by using confocal microscopy in vivo

PURPOSE

To quantify keratocyte density according to stromal region and subject age and to measure the thickness of the normal human cornea and its layers in vivo.

METHODS

Seventy normal corneas of 70 subjects were examined by confocal microscopy (contact lens wearers were excluded). Ages of subjects ranged from 12 to 80 years, with 10 subjects per decade. Images were recorded by continuously focusing the optical section through the full-thickness central cornea. Two independent human observers manually identified bright objects (keratocyte nuclei) against a dark background to quantify keratocyte density. This method was validated histologically in three human corneas. Thickness measurements were obtained by plotting mean reflected light intensity in images against corneal depth, and calculating distances between intensity peaks that corresponded to corneal layers.

RESULTS

Full-thickness central keratocyte density was 20,522 +/- 2,981 cells/mm(3) (mean +/- SD, n = 69). The number of keratocytes in a full-thickness column of central stroma, which had a cross-sectional area of 1 mm(2), was 9624 +/- 1385 cells. Keratocyte density was highest in the anterior 10% of the stroma. Full-thickness keratocyte density was correlated with age (r = -0.62, P < 0.001), decreasing 0.45% per year. Central corneal thickness was 563.0 +/- 31.1 microm (mean +/- SD) and central epithelial thickness was 48.6 +/- 5.1 microm.

CONCLUSIONS

This is the first study to quantify regional keratocyte density comprehensively in vivo across a broad age range of normal human subjects. The method was acceptable to both subject and observer, and may prove useful for quantifying keratocyte density in patients with corneal disorders or after corneal surgery.

Prostaglandin E(2)-dependent production of latent matrix metalloproteinase-9 in cultures of human fetal membranes

Studies in our laboratory have shown that structural changes in cervical biopsied fetal membranes, prior to labour, coincide with differences in the expression of the gelatinase enzyme, latent matrix metalloproteinase-9 (MMP-9). Concurrently, in vivo, there is an increase in the expression of prostaglandins, notably prostaglandin E(2) (PGE(2)), which has been shown to regulate the expression of MMPs in other systems. The aim of this study was to test the hypothesis (using an in-vitro culture model) that endogenously produced PGE(2) has a role in the elevation of MMP-9 described in vivo. Non-infected fetal membranes sampled from women undergoing elective Caesarean section were stimulated with 10% (v/v) fetal bovine serum (FBS), a known inducer of prostaglandins. This activation resulted in a time-dependent increase in the secretion of PGE(2) into the media, as determined by enzyme-linked immunosorbent assay (day 1: 19 +/- 9 pg/ml/24 h to 358 +/- 54 pg/ml/24 h by day 4). A similar pattern of secretion of latent MMP-9 was observed in parallel with the increase in PGE(2) in the same culture media (day 1: 1.63 +/- 0.17 ng/ml/24 h to 4.2 +/- 1.4 ng/ml/24 h by day 4). When both molecules were compared, a significant (P: < 0.01) positive correlation (r = 0.623) was observed. Secretion of the tissue inhibitor of MMPs-9 (TIMP-1) was not significantly different between untreated (3.07 +/- 0.266 microg/ml/24 h) and FBS-treated (3. 85 +/- 0.24 microg/ml/24 h) cultures during the first 4 days in culture. Prostaglandin synthesis inhibition studies using indomethacin (100 micromol/l) resulted in a 70-80% reduction in the activated secretion of latent MMP-9. Direct PGE(2) stimulation of cultures resulted in the bell shaped dose-response curve with concentrations of 1-100 nmol/l (which are within the range secreted in culture in response to FBS), stimulating significant latent MMP-9 secretion. These results suggest a link between endogenous PGE(2) and latent MMP-9 production in human fetal membranes, raising the possibility that PGE(2) has a role in the mechanism of fetal membrane structural changes and, hence, in parturition-associated membrane rupture.

Menstruation, the oral contraceptive pill, and acute appendicitis

OBJECTIVE

To find out if there was any association between histologically confirmed acute appendicitis, menstruation, and the use of the oral contraceptive pill.

DESIGN

Retrospective study.

SETTING

District general hospital, Scotland.

SUBJECTS

366 consecutive patients (median age 21, range 10-51) with histologically confirmed acute appendicitis during the period 1981-1990 were studied, 314 of whom were having menstrual cycles. 208 patients with physiological menstrual cycle were included in the study, and 82 patients were taking the oral contraceptive pill.

INTERVENTIONS

Prospectively collected standardised data using computer assisted diagnosis of acute abdominal pain was used to review patients with histologically confirmed acute appendicitis.

RESULTS

Acute appendicitis was confirmed in 17/208 of patients (8%) who were menstruating, which is significantly less than might be expected (p < 0.003). 5/82 (6%) of those taking oral contraception had withdrawal bleeding and acute appendicitis (p = 0.2).

CONCLUSIONS

Acute appendicitis is less common among women during physiological menstruation, but no differences are noted during the withdrawal bleeding phase when taking oral contraception.

Increased concentration of pro-matrix metalloproteinase 9 in term fetal membranes overlying the cervix before labor: implications for membrane remodeling and rupture

OBJECTIVES

Regional structural alterations that develop before labor are important in the mechanisms of both physiologic and pathologic membrane rupture, because they are also detected in preterm prelabor rupture of the fetal membranes, the most common cause of preterm birth (as great as 60%). Matrix metalloproteinases are located in the fetal membranes and are the main mediators of extracellular matrix degradation. The objective of this study was to examine whether gelatinases (matrix metalloproteinases 2 and 9) could be involved in the development of these regional structural changes seen at term before labor.

STUDY DESIGN

Fetal membranes from patients undergoing elective cesarean delivery were regionally sampled from over the cervix (cervical membranes) and midway between this area and the placental edge (midzone). Fetal membranes obtained after spontaneous labor and delivery at term were also regionally sampled. Matrix metalloproteinase 2 and 9 activities were assessed by gelatin zymography, whereas total matrix metalloproteinase 9 protein was determined by enzyme-linked immunosorbent assay.

RESULTS

Zymography only detected activity corresponding to the pro-matrix metalloproteinase 2 (72 kd) and 9 (92 kd) forms in prelabor fetal membranes. Although the levels of pro-matrix metalloproteinase 2 showed no regional differences, the pro-matrix metalloproteinase 9 level was higher in the cervical area than in the midzone (2.5 +/- 0.98 vs 0.76 +/- 0.28 optical density units/20 microg protein; P <.01). The concentration of pro-matrix metalloproteinase 9 protein in the cervical area was also significantly higher than that in the midzone (6.69 +/- 4.8 vs 1.58 +/- 1.14 ng/mg protein; P <.01). After delivery both pro-matrix metalloproteinase 2 and 9 activities were elevated, whereas pro-matrix metalloproteinase 9 protein activity showed no regional difference between the rupture site and midzone (23.47 +/- 4.5 vs 25. 3 +/- 6.2 ng/mg protein). Active bands of matrix metalloproteinases 2 (66 kd) and 9 (83 kd) were also detected after delivery.

CONCLUSION

This study suggests that a specific regional induction of pro-matrix metalloproteinase 9 occurs in the cervical area before labor and may play a role in "programming" this area for subsequent rupture after activation during labor.

Vascular endothelial growth factor and endometriotic angiogenesis

Peritoneal endometriosis is a significant debilitating gynaecological problem of widespread prevalence. It is now generally accepted that the pathogenesis of peritoneal endometriosis involves the implantation of exfoliated endometrium. Essential for its survival is the generation and maintenance of an extensive blood supply both within and surrounding the ectopic tissue. The vascular endothelial growth factor (VEGF) family of angiogenic molecules is involved in both physiological angiogenesis, and a number of pathological conditions that are characterized by excessive angiogenesis. Increasing evidence suggests that the VEGF family may also be involved with both the aetiology and maintenance of peritoneal endometriosis. Sources of this factor include the eutopic endometrium, ectopic endometriotic tissue and peritoneal fluid macrophages. Important to its aetiology is the correct peritoneal environment in which the exfoliated endometrium is seeded and implants. Established ectopic tissue is then dependent on the peritoneal environment for its survival, an environment that supports angiogenesis. Our increasing knowledge of the involvement of the VEGF family in endometriotic angiogenesis raises the possibility of novel approaches to its medical management, with particular focus on the anti-angiogenic control of the action of VEGF.

Increased incidence of apoptosis in non-labour-affected cytotrophoblast cells in term fetal membranes overlying the cervix

A regional reduction in the cellularity of the cytotrophoblastic and decidual layers occurs in the fetal membranes overlying the cervix in the lower uterine segment prior to labour. Although the mechanism(s) involved are not known it could result from regionally increased apoptosis, the histological manifestation of programmed cell death, or decreased proliferation. Apoptosis was assessed in regionally sampled fetal membranes from women undergoing elective Caesarean section (n = 14) by the presence of apoptotic bodies by light and electron microscopy. Cell proliferation was assessed by immunocytochemical detection of the protein Ki-67. Apoptotic bodies were identified in all regions of the fetal membrane with the highest incidence found within the cytotrophoblast layer. However, this layer in fetal membranes biopsied over the cervix contained significantly more apoptotic bodies (mean +/- SD 0.085 +/- 0.020%) compared to the layer in fetal membranes obtained from the mid-zone (0.020 +/- 0.008%) apoptotic bodies. Isolated Ki-67 positive cells were detected in the cytotrophoblast layer, but no regional differences in their incidence were seen. Fetal membranes also failed to exhibit significant immunoreactivity for BCL-2 but exhibited strong BAX immunoreactivity within the decidual layer. We conclude that the regionally increased incidence of apoptosis in the cytotrophoblastic layer in the membrane overlying the cervix may account for the reduction in its cellularity but not the relative decrease in the decidual layer. Given the consequence of the loss of local function in degrading uterotonins and stabilizing the fetal membrane, the study of the regulation of apoptosis in these cells may have important implications for fetal membrane rupture and parturition.

Synthetic [5,5] trans-fused indane lactones as inhibitors of thrombin

Synthesis of trans-fused lactones containing the indane nucleus has resulted in a series of potent acylating inhibitors of thrombin. As an example compound 11e has an apparent second order rate constant of 11 x 10(6) M(-1)sec(-1) for the inhibition of thrombin. The anticoagulant activity of these compounds is discussed.

Structural characteristics of term human fetal membranes prior to labour: identification of an area of altered morphology overlying the cervix

Premature rupture of fetal membranes can have serious clinical implications, especially for the initiation of preterm labour and its consequences. To account for this phenomenon many studies have attempted to identify membrane features that may be uniquely associated with the site of rupture. Our previous work has identified an area of the fetal membrane, following spontaneous term birth which exhibits alterations consistent with structural weakness. The aim of this study was to determine if these changes existed prior to labour. In formalin-fixed paraffin-embedded tissue sections an area of the fetal membrane overlying the cervix, termed the 'cervical membranes', was characterized by an increased thickness of the connective tissue layer (215% increase, P < 0.01) and decreased thickness of both the cytotrophoblast (36% reduction, P < 0.01) and decidual layers (64% reduction, P < 0.01) compared to the rest of the membrane. This resulted in the cervical membranes being significantly thinner (P < 0.05) than the rest of the membrane. Similar changes were also detected in frozen sections of fetal membranes. These regional differences have two important implications in that: (i) the cervical membrane may represent a region of structural weakness susceptible to rupture during labour, and (ii) the paracrine relationships between fetal membranes and the myometrium may be qualitatively affected within different regions of the uterus.

5,5-trans lactone-containing inhibitors of serine proteases: identification of a novel, acylating thrombin inhibitor

Synthesis of a variety of 5,5-trans fused lactones, related to compounds found in extracts of Lantana camara, has provided a series of novel acylating inhibitors of human thrombin, trypsin, chymotrypsin and human leucocyte elastase. The most effective thrombin inhibitor is 7 with an IC50 of 130 nM and a Kobs/[1] of 4,000 M-1 s-1.

Intraocular pressure in rabbits by telemetry II: effects of animal handling and drugs

PURPOSE

To measure under carefully controlled conditions the effects in the rabbit eye of commonly used therapeutic agents for glaucoma.

METHODS

Rabbits were outfitted in one eye with an implantable telemetric pressure transducer and monitored for several months under controlled conditions of light/ dark and handling. Effects of tonometry, handling, water drinking, and instillation of topical ophthalmic medications on intraocular pressure were recorded during each 24-hour day/night cycle.

RESULTS

Pneumatonometry, animal handling, and water drinking all had an effect on intraocular pressure that in many instances was of the same magnitude as the effects of pharmacologic agents. Dorzolamide and timolol caused a sustained reduction of intraocular pressure during the nocturnal period. Epinephrine had a biphasic effect, causing an immediate pressure elevation followed by a prolonged depression. Apraclonidine, latanoprost, and pilocarpine had no measurable effect.

CONCLUSIONS

Continuous telemetric measurement of intraocular pressure in rabbits permits the measurement of uncontrollable artifacts that occur with tonometric measurements and animal handling. If environmental conditions are rigidly controlled, this method is very sensitive for detecting therapeutic effects of candidates for ocular hypotensive drugs. When healthy animals are used, the method appears to be more sensitive for drugs that affect aqueous humor formation than for drugs that affect aqueous humor outflow resistance.

Glutathione-dependent antioxidant systems in the mammalian inner ear: effects of aging, ototoxic drugs and noise

Glutathione and glutathione-related enzymes protect against oxidative (free radical) cell injury. This study presents basic information on this antioxidant system in inner ear tissues and preliminary results of the influence of age, ototoxic drugs and noise. These conditions affect inner ear function, possibly through free radicals, and are therefore expected to affect cellular defense mechanisms. In 24-month old Fischer 344 rats, a standard model for aging, glutathione levels were significantly decreased in the auditory nerve by 86% as compared to 3-month old rats but remained unchanged in other cochlear tissues. In guinea pig, the common model for drug- and noise-induced trauma, glutathione levels in the cochlear sensory epithelium were about 8-fold higher (223 +/- 35 nmol glutathione/mg protein) than in the rat. Cochlear glutathione S-transferase and glutathione reductase activities were similar between the two species, whereas selenium-independent glutathione peroxidase was strikingly lower in guinea pig than in rat (9 +/- 3 nmol vs. 161 +/- 84 nmol glutathione converted/mg protein/min). Cisplatin treatment of guinea pigs (56 dB threshold shift at 18 kHz) significantly lowered cochlear glutathione levels by 65% and glutathione S-transferase activity by 44%. Gentamicin treatment (80 dB threshold shift at 18 kHz) and noise exposure (43 dB threshold shift at 18 kHz) did not affect glutathione at the tissue level. These results demonstrate species differences in cochlear glutathione and glutathione-related enzymes. The antioxidant system is sensitive towards environmental influences as seen for age and cisplatin. For gentamicin and noise trauma, whole tissue glutathione and enzyme levels do not correlate with functional damage. This indicates that glutathione homeostasis is largely maintained in the cochlea and that biochemical changes, if they occur under these conditions, may be limited to specific cells.

Sialyl Lewis(x) analog improves liver function by decreasing neutrophil migration after hemorrhagic shock

BACKGROUND

Little is known about the changes in the hepatic microcirculation and the leukocyte-endothelial adhesion processes during the early reperfusion period after resuscitation in hemorrhagic shock. P-selectin and its natural ligand Sialyl Lewis(x) (SLe(x)) are involved in the early stages of reperfusion events leading to neutrophil migration. Therefore, the aim of this study was to investigate the effect of the administration of CY-1503 [corrected], a synthetic SLe(x) analog, in the liver inflammatory response and neutrophil migration after hemorrhagic shock.

MATERIALS AND METHODS

Rats, each weighing 275 to 300 grams, were subjected to 60 minutes of pressure controlled hemorrhagic shock. After this period, animals were resuscitated according to the following protocol: shed blood was reinfused to equal 50% of the total volume bled, and the other 50% was replaced with 3x volume of Ringer's lactated solution. Animals were divided into sham and two study groups to receive vehicle (controls) and CY-1503 [corrected] (10 mg/kg intravenously) diluted in 1 mL of normal saline 45 minutes after initiating hemorrhagic shock. The following parameters were analyzed: 7-day survival, liver injury tests, liver tissue myeloperoxidase as an index of neutrophil infiltration, and liver histology.

RESULTS

Survival was significantly increased from 48% in the controls to 90% in the CY-1503 [corrected] treated group. Animals treated with the SLe(x) analog showed significantly better mean arterial blood pressure after 15 minutes after resuscitation. Also, the treated group showed a marked decrease in liver enzymes levels at 5 minutes and 4 hours after reperfusion. Neutrophil migration was significantly ameliorated as reflected by decreased myeloperoxidase levels in the SLe(x) analog treated group. Furthermore, we observed improved histologic damage scores in the treated group when compared with controls.

CONCLUSIONS

The SLe(x) analog, CY-1503 [corrected], had a protective effect in ischemic livers by decreasing neutrophil migration after hemorrhagic shock and resuscitation. This protective effect also resulted in improved survival and mean arterial blood pressure after resuscitation.

Decreased levels of the potent regulator of monocyte/macrophage activation, interleukin-13, in the peritoneal fluid of patients with endometriosis

Endometriosis is characterized by an increase in the number, activation and secretory activity of peritoneal fluid macrophages. Factors regulating the activation of these cells may be important in the pathophysiology of this disease. In this study we measured by enzyme-linked immunosorbent assay the concentrations of the macrophage inhibitory factor interleukin (IL)-13 in the peritoneal fluid of women with and without endometriosis. It was found that women with endometriosis had significantly lower amounts of IL-13 (95 +/- 9.8 pg/ml) in peritoneal fluid, compared with women without endometriosis (115 +/- 30 pg/ml) (P < 0.01). No cycle-specific variation was evident for either group. Another macrophage inhibitory interleukin (IL-10) was also measured, but no differences between women with (16.1 +/- 13.2 pg/ml) or without (10.3 +/- 5.6 pg/ml) endometriosis were seen. The immunolocalization of IL-13 was assessed in eutopic and ectopic endometrium and in isolated peritoneal fluid cells. Glandular epithelial cells and stromal cells in both eutopic and ectopic endometrium were immunopositive for IL-13. No cycle-specific differences in the immunolocalization of IL-13 were seen. In conclusion, the reduced amounts of IL-13 in the peritoneal fluid of women with endometriosis may lead to a lack of suppression of macrophage activation, thereby contributing to the overall pathogenesis of this disease.

Selective antagonism of the AT1 receptor inhibits the effect of angiotensin II on DNA and protein synthesis of rat proximal tubular cells

The proliferation and hypertrophy of renal tubular cells are primary features in the progression of both acute and chronic renal disease often indicating a poor prognosis. Angiotensin II (ANG II), acting alone or in combination with other growth factors, has been implicated in this process. The aims of this study were to identify the importance of both ANG II and serum-derived factors upon cellular DNA synthesis and protein synthesis in renal proximal tubular cells and to identify the roles of the ANG II receptor subtypes in these processes together with the underlying intracellular signalling mechanisms involved. Primary cultures of renal proximal tubular cells were prepared from freshly isolated rat kidney cortex. Cells were cultured in either serum-replete Dulbecco's modified Eagle's/Ham's F12 or serum-deplete defined medium containing insulin, hydrocortisone, sodium selenite, transferrin, and tri-iodothyronine. Cells were incubated with ANG II (10(-10), 10(-8), 10(-6) M) for 24-120 h either alone or in combination with losartan, PD123319, or pertussis toxin. Incubation of proximal tubular cells in the presence of serum and ANG II (10(-8) M) induced a significant early (24 h) increase in DNA synthesis, together with a significant late (96 h) increase in protein content. [3H]thymidine uptake increased by 56% (p < 0.001) and total protein content by 23% (p < 0.05). In defined media, ANG II (10(-8) M) stimulated protein synthesis only. [3H]uridine uptake, [3H]leucine uptake, and total protein content increased by 25, 57, and 17% (p < 0.05), respectively. In both serum-replete and serum-deplete media, the effects upon protein synthesis of ANG II were inhibited by pertussis toxin and losartan, but not by PD123319. ANG II is clearly a potent stimulator of renal tubular cell DNA and protein synthesis-a response mediated via the AT1 receptor coupled to a pertussis toxin sensitive Gi protein.

Recurrent appendicitis

BACKGROUND

The existence of appendiceal inflammation which resolves spontaneously without surgical intervention has long been controversial. This study was undertaken, therefore, to determine the existence and incidence of recurrent appendicitis.

METHODS

The existence of a large database of patients with abdominal pain enabled a retrospective study of the casenotes of the 1084 patients who had an inflammed appendix removed between January 1982 and December 1991 in a Scottish District General Hospital. Sixty consecutive patients who had a normal appendix removed during this period were also studied.

RESULTS

Seventy-one patients (6.5 per cent) attended the accident and emergency department 89 times with symptoms and signs compatible with appendicitis which resolved spontaneously between 3 weeks and 12 years before an attendance during which an inflamed appendix was removed. There were significant differences in clinical signs and symptoms (using the Alvarado scoring system) between patients whose symptoms resolved, those with a normal and those with an inflamed appendix. Those who had a normal appendix removed were more likely to be female than those with resolving symptoms (67 versus 42 per cent, P < 0.01).

CONCLUSION

Recurrent appendicitis exists and affects at least 6.5 per cent of those who ultimately have an inflamed appendix removed.

Immunolocalization of the apoptosis regulating proteins Bcl-2 and Bax in human endometrium and isolated peritoneal fluid macrophages in endometriosis

Endometriosis, a debilitating disease associated with infertility, is characterized by the prolonged presence of ectopic endometrial tissue and the involvement of activated peritoneal fluid macrophages. Apoptosis, which occurs in both endometrium and peritoneal fluid macrophages, is controlled in part by members of the Bcl-2/Bax family of proteins. Here, through immunohistochemical staining, we investigated the Bcl-2/Bax status in endometrium and peritoneal fluid macrophages in endometriosis. Bcl-2/Bax immunoreactivity was found predominantly in the glandular epithelial cells, mainly during the proliferative phase of the menstrual cycle for Bcl-2 but throughout the entire menstrual cycle for Bax. Ectopic endometrium contained a population of Bcl-2 positive. Bax negative tissue macrophages. Fluorescence-activated cell sorting of isolated peritoneal fluid macrophages showed that women with endometriosis had a significantly higher proportion of Bcl-2 positive macrophages than the non-endometriotic group. The proportion of Bax positive peritoneal fluid macrophages was significantly elevated in women without endometriosis. The increased proportion of Bcl-2 positive macrophages found in women with endometriosis may predispose these cells to resist apoptosis. The continued survival of these active cells could have important consequences for the survival and proliferation of the ectopic endometrial tissue.

Maternal plasma levels of vascular endothelial growth factor in normotensive pregnancies and in pregnancies complicated by pre-eclampsia

We have measured the level of vascular endothelial growth factor (VEGF) in maternal plasma during normotensive pregnancy and in pregnancies complicated by pre-eclampsia. VEGF was measured using a competitive enzyme immunoassay. Plasma VEGF was significantly elevated (P < 0.0001) in the pre-eclamptic group (median value 32.7 ng mL-1, range 10.3-64.0), compared with the normotensive group (median value 11.7 ng mL-1, range 6.3-24.3). VEGF is a potent regulator of endothelial cell function. The increased level found in women with pre-eclampsia indicates that VEGF may be involved in the maternal endothelial cell dysfunction associated with this condition. An increase in VEGF, a potent regulator of microvascular permeability, may also contribute to the extravasation of plasma proteins and the subsequent development of proteinuria, both characteristic features of pre-eclampsia.

Vascular endothelial growth factor is produced by peritoneal fluid macrophages in endometriosis and is regulated by ovarian steroids

Angiogenesis is important in the pathophysiology of endometriosis, a condition characterized by implantation of ectopic endometrium in the peritoneal cavity. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor involved in physiological and pathological angiogenesis, and elevated levels of VEGF are found in peritoneal fluid of patients with endometriosis. Our aim was to investigate the site of expression and regulation of VEGF in endometriosis. VEGF immunoreactivity was found in tissue macrophages present in ectopic endometrium and in activated peritoneal fluid macrophages. Macrophage activation was highest in women with endometriosis, and media conditioned by peritoneal fluid macrophages from these women caused a VEGF-dependent increase in endothelial cell proliferation above that seen from normal women. Peritoneal fluid macrophages secreted VEGF in response to ovarian steroids, and this secretion was enhanced after activation with lipopolysaccharide. Peritoneal fluid macrophages expressed receptors for steroid hormones. VEGF receptors flt and KDR (kinase domain receptor) were also detected, suggesting autocrine regulation. During the menstrual cycle, expression of flt was constant but that of KDR was increased in the luteal phase, at which time the cells migrated in response to VEGF. KDR expression and the migratory response were significantly higher in patients with endometriosis. This study demonstrates that activated macrophages are a major source of VEGF in endometriosis and that this expression is regulated directly by ovarian steroids.