Qualification of a 17β-estradiol (E2) Assay in Sprague Dawley Rat Serum

Introduction/Objective

Significant technical issues are associated with methods used for the measurement of estradiol.The objective of this study was to qualify an electrochemiluminescent (ECL) assay for the quantification of 17β-estradiol (E2) in rat serum. Hemolysis has been identified as a factor that interferes with accurate measurement.The impact of hemolysis was also assessed.

Methods

Approximately 1.0 mL of whole blood was collected from male and female rats into separate red top tubes and processed to serum.

The LoQ for E2 was evaluated by analyzing the low calibrator or at least 6 serum samples diluted to produce a value at the low end of the reportable range 8 times in the same run.The mean, standard deviation, and %CV were calculated for each sample.The data set was analyzed by plotting the data and determining the concentration at the intersection of the precision profile curve.

Linearity of dilution was performed using commercially available calibration verification material and E2 stripped rat serum.The correlation coefficient, the slope, and the % Nominal were calculated.

Intra assay precision was evaluated by analyzing 8 consecutive times in a single run one rat serum sample that was not diluted or spiked. This analysis was performed during the evaluation of the LoQ.The mean, SD and %CV were calculated.

The interference of hemolysis with the E2 assay was tested by analyzing at least 5 rat serum samples/pools spiked with hemolyzed rat serum at different hemoglobin concentrations.The %RE was calculated.

Results

The LoQ assays were acceptable. For all samples tested, the % CV was less than or equal to 25%.The LoQ was verified to be 8.50 pg/mL. The %CV was 15.6%. For samples with estradiol concentrations below the LoQ, a value of 4.25 pg/ml was reported.

Linearity of dilution for E2 was acceptable.The correlation coefficients were greater than or equal to 0.9000, the slopes were between 0.7500 and 1.2500, and the % nominals for each level were between 75-125%.

The intra-assay precision was considered acceptable with a %CV of 8.6%.

There was no hemolysis interference in the assay when samples were spiked with hemoglobin concentrations of up to 70 mg/dL, based on the %RE of less than or equal to 25% of non-hemolyzed samples.

Conclusion

Qualification of the ECL method, demonstrates the assay is suitable for the determination of E2 in serum samples from rats and absence of hemolysis interference up to 70 mg/dL of hemoglobin concentration.

Blebbistatin-Loaded Poly(d,l-lactide-co-glycolide) Particles For Treating Arthrofibrosis

Joint immobility is a debilitating complication of articular trauma that is characterized by thickening and stiffening of the joint capsule and the formation of fibrotic lesions inside joints. Capsule release surgery can temporarily restore mobility, but contraction often recurs due to the contractile activities of fibroblasts, which exert tension on the capsule ECM via nonmuscle myosin II. Based on these findings we hypothesized that blebbistatin, a drug that reversibly inhibits the activity of this protein, would relax ECM tension imposed by fibroblasts and reduce fibrosis. In this study, we characterized the effectiveness of blebbistatin as an anticontractile treatment. Given that sustained suppression of contractile activity may be required to achieve capsule release and reduce fibrosis, we compared the effects on fibroblast-mediated collagen ECM displacement of blebbistatin-loaded poly(lactide-co-gylcolide) (PLGA) particles versus bolus blebbistatin dosing. Time-lapse imaging of fluorescent microspheres embedded in collagen gels confirmed that PLGA/blebbistatin inhibited force generation and reduced both gel displacement and rate of displacement. In addition, collagen production at 10 days was significantly reduced. Taken together, these data indicate that blebbistatin-loaded PLGA particles can be used to inhibit fibroblast force-generation and reduce collagen production and lay the foundation for optimization of drug delivery technology for treating arthrofibrosis.

Undetectable pregnancy-associated plasma protein-A in antenatal serum Down's syndrome screening: a case of assay interference

Serum pregnancy-associated plasma protein-A (PAPP-A) is measured in Down's syndrome screening, routinely offered to women in pregnancy. We present the case of an undetectable pregnancy-associated plasma protein-A concentration on the PerkinElmer AutoDELFIA system where immunoassay interference was suspected. Investigations performed, including dilution and recovery studies and antibody-blocking tube incubations, all yielded serum pregnancy-associated plasma protein-A concentrations of <25 mU/L. Pregnancy-associated plasma protein-A was also undetectable on two alternative pregnancy-associated plasma protein-A assays. An experimental manual Delfia procedure suggested the site of interference was between the secondary antibody and the pregnancy-associated plasma protein-A molecule. This case of negative interference in the PerkinElmer pregnancy-associated plasma protein-A assay produced a falsely high Down's syndrome risk that might have led to an unnecessary invasive procedure with the potential for fetal loss. This highlights the need for Down's syndrome screening laboratories to be vigilant to immunoassay interference due to the significant impact of the results on patient decision outcome.

Buprenorphine/naloxone and methadone maintenance treatment outcomes for opioid analgesic, heroin, and combined users: findings from starting treatment with agonist replacement therapies (START)

OBJECTIVE

The objective of this secondary analysis was to explore differences in baseline clinical characteristics and opioid replacement therapy treatment outcomes by type (heroin, opioid analgesic [OA], or combined [heroin and OA]) and route (injector or non-injector) of opioid use.

METHOD

A total of 1,269 participants (32.2% female) were randomized to receive one of two study medications (methadone or buprenorphine/naloxone [BUP]). Of these, 731 participants completed the 24-week active medication phase. Treatment outcomes were opioid use during the final 30 days of treatment (among treatment completers) and treatment attrition.

RESULTS

Non-opioid substance dependence diagnoses and injecting differentiated heroin and combined users from OA users. Non-opioid substance dependence diagnoses and greater heroin use differentiated injectors from non-injectors. Further, injectors were more likely to be using at end of treatment compared with non-injectors. OA users were more likely to complete treatment compared with heroin users and combined users. Non-injectors were more likely than injectors to complete treatment. There were no interactions between type of opioid used or injection status and treatment assignment (methadone or BUP) on either opioid use or treatment attrition.

CONCLUSIONS

Findings indicate that substance use severity differentiates heroin users from OA users and injectors from non-injectors. Irrespective of medication, heroin use and injecting are associated with treatment attrition and opioid misuse during treatment. These results have particular clinical interest, as there is no evidence of superiority of BUP over methadone for treating OA users versus heroin users.

Phenotypic heterogeneity of genomic disorders and rare copy-number variants

BACKGROUND

Some copy-number variants are associated with genomic disorders with extreme phenotypic heterogeneity. The cause of this variation is unknown, which presents challenges in genetic diagnosis, counseling, and management.

METHODS

We analyzed the genomes of 2312 children known to carry a copy-number variant associated with intellectual disability and congenital abnormalities, using array comparative genomic hybridization.

RESULTS

Among the affected children, 10.1% carried a second large copy-number variant in addition to the primary genetic lesion. We identified seven genomic disorders, each defined by a specific copy-number variant, in which the affected children were more likely to carry multiple copy-number variants than were controls. We found that syndromic disorders could be distinguished from those with extreme phenotypic heterogeneity on the basis of the total number of copy-number variants and whether the variants are inherited or de novo. Children who carried two large copy-number variants of unknown clinical significance were eight times as likely to have developmental delay as were controls (odds ratio, 8.16; 95% confidence interval, 5.33 to 13.07; P=2.11×10(-38)). Among affected children, inherited copy-number variants tended to co-occur with a second-site large copy-number variant (Spearman correlation coefficient, 0.66; P<0.001). Boys were more likely than girls to have disorders of phenotypic heterogeneity (P<0.001), and mothers were more likely than fathers to transmit second-site copy-number variants to their offspring (P=0.02).

CONCLUSIONS

Multiple, large copy-number variants, including those of unknown pathogenic significance, compound to result in a severe clinical presentation, and secondary copy-number variants are preferentially transmitted from maternal carriers. (Funded by the Simons Foundation Autism Research Initiative and the National Institutes of Health.).

Genotype-phenotype analysis of 4q deletion syndrome: proposal of a critical region

Chromosome 4q deletion syndrome (4q- syndrome) is a rare condition, with an estimated incidence of 1 in 100,000. Although variable, the clinical spectrum commonly includes craniofacial, developmental, digital, skeletal, and cardiac involvement. Data on the genotype-phenotype correlation within the 4q arm are limited. We present detailed clinical and genetic information by array CGH on 20 patients with 4q deletions. We identified a patient who has a ∼465 kb deletion (186,770,069-187,234,800, hg18 coordinates) in 4q35.1 with all clinical features for 4q deletion syndrome except for developmental delay, suggesting that this is a critical region for this condition and a specific gene responsible for orofacial clefts and congenital heart defects resides in this region. Since the patients with terminal deletions all had cleft palate, our results provide further evidence that a gene associated with clefts is located on the terminal segment of 4q. By comparing and contrasting our patients' genetic information and clinical features, we found significant genotype-phenotype correlations at a single gene level linking specific phenotypes to individual genes. Based on these data, we constructed a hypothetical partial phenotype-genotype map for chromosome 4q which includes BMP3, SEC31A, MAPK10, SPARCL1, DMP1, IBSP, PKD2, GRID2, PITX2, NEUROG2, ANK2, FGF2, HAND2, and DUX4 genes.

Assessment of Bradykinesia in Parkinson's disease patients through a multi-parametric system

The aim of this paper is to describe and present the results of the automatic detection and assessment of bradykinesia in motor disease patients using wireless, wearable accelerometers. The current work is related to a module of the PERFORM system, a FP7 project from the European Commission, that aims at providing an innovative and reliable tool, able to evaluate, monitor and manage patients suffering from Parkinson's disease. The assessment procedure was carried out through a developed C# library that detects the activities of the patient using an activity recognition algorithm and classifies the data using a Support Vector Machine trained with data coming from previous test phases. The accuracy between the output of the automatic detection and the evaluation of the clinician both expressed with the Unified Parkinson's disease Rating Scale, presents an average value of [68.3 ± 8.9]%. A meta-analysis algorithm is used in order to improve the accuracy to an average value of [74.4 ± 14.9]%. Future work will include a personalized training of the classifiers in order to achieve a higher level of accuracy.

Cytoskeletal dissolution blocks oxidant release and cell death in injured cartilage

The mechanisms by which articular surface impact causes post-traumatic osteoarthritis are not well understood, but studies of cartilage explants implicate the mitochondrial electron transport chain as a source of oxidants that cause chondrocyte death from mechanical injury. The linkage of mitochondria to the cytoskeleton suggests that they might release oxidants in response to mechanical strain, an effect that disrupting the cytoskeleton would prevent. To test this we investigated the effects of agents that promote the dissolution of microfilaments (cytochalasin B) or microtubules (nocodazole) on oxidant production and chondrocyte death following impact injury. Osteochondral explants treated with cytochalasin B or nocodazole for 4 h were impacted (7 J/cm(2)) and stained for oxidant production directly after impact and for cell viability 24 h after impact. Surfaces within and outside impact sites were then imaged by confocal microscopy. Both agents significantly reduced impact-induced oxidant release (p < 0.05); however, cytochalasin B was more effective than nocodazole (>60% reduction vs. 40% reduction, respectively). Both agents also prevented impact induced cell death. Dissolution of the cytoskeleton by both drugs was confirmed by phalloidin staining and confocal microscopy. These findings show that chondrocyte mortality from impact injury depends substantially on mitochondrial-cytoskeletal linkage, suggesting new approaches to stem mechanically induced cartilage degeneration.

Repeated measurement of mechanical properties in viable osteochondral explants following a single blunt impact injury

The objective of this work was to develop a method for repeated same-site measurement of mechanical properties suitable for the detection of degenerative changes in a biologically active explant model after a single blunt impact injury. Focal blunt impact injuries to articular surfaces lead to local cartilage degeneration and loss of mechanical properties. We employed a repeated measurement methodology to determine variations in mechanical same-site properties before and after injury in living cartilage, with the hypothesis that normalization with initial mechanical properties may provide a clearer evaluation of impact effects and improve our understanding of the biologic responses to impact injury. Bovine osteochondral explants were cultured for up to 14 days after impact injury. Indentation tests were performed before and after impact injury to assess relative changes in mechanical properties. Creep strain increased significantly in impacted explants after 7 days and in both impacted and control explants after 14 days. Further analysis at 14 days revealed decreases in stretch factor beta, creep time constant and local compressive modulus. A repeated measures methodology reliably detected changes in the mechanical behaviour of viable osteochondral explants after a single impact injury.

Biomechanical disc culture system: feasibility study using rat intervertebral discs

A small-scale biomechanical disc culture system was designed to stimulate intervertebral disc (IVD) 'motion segment' in culture environment with load-controlled compression and combined load (compression+shear). After 7 days of diurnal mechanical loading, cell viability of discs stimulated with static compression load (0.25 MPa) and static combined load (compression (0.25 MPa)+shear (1.5N)) were similar (>90 per cent) to unloaded controls. Mechanically stimulated discs showed decrease in static/dynamic moduli, early stress relaxation, and loss of disc height after 7 days of diurnal loading. Histological data of discs indicated load-induced transformations that were not apparent in controls. The feasibility of studying the mechanobiology of intact IVD as a motion segment was demonstrated. Media conditioning (improve tissue stability in long-term culture) and application of biochemical gene expression assays (differential tissue response to types of mechanical stimulation) are proposed as future improvements. The study suggests that the limitations in studying mechanobiology of IVD pathology in vitro can be overcome and it is possible to understand the physiologically relevant mechanism of IVD pathology.

QT interval screening in methadone maintenance treatment: report of a SAMHSA expert panel

In an effort to enhance patient safety in opioid treatment programs, the Substance Abuse and Mental Health Saervices Administration convened a multi-disciplinary Expert Panel on the Cardiac Effects of Methadone. Panel members (Appendix A) reviewed the literature, regulatory actions, professional guidances, and opioid treatment program experiences regarding adverse cardiac events associated with methadone. The Panel concluded that, to the extent possible, every opioid treatment program should have a universal Cardiac Risk Management Plan (incorporating clinical assessment, electrocardiogram assessment, risk stratification, and prevention of drug interactions) for all patients and should strongly consider patient-specific risk minimization strategies (such as careful patient monitoring, obtaining electrocardiograms as indicated by a particular patient's risk profile, and adjusting the methadone dose as needed) for patients with identified risk factors for adverse cardiac events. The Panel also suggested specific modifications to informed consent documents, patient education, staff education, and methadone protocols.

Rotenone prevents impact-induced chondrocyte death

Mechanical insult to articular cartilage kills chondrocytes, an event that may increase the risk of posttraumatic osteoarthritis. Recent reports indicate that antioxidants decrease impact-induced chondrocyte death, but the source(s) of oxidants, the time course of oxidant release, and the identity of the oxidative species generated in response to injury are unknown. A better understanding of these processes could lead to new treatments of acute joint injuries. To that end, we studied the kinetics and distribution of oxidant production in osteochondral explants subjected to a single, blunt-impact injury. We followed superoxide production by measuring the time-dependent accumulation of chondrocyte nuclei stained with the superoxide-sensitive probe dihydroethidium. The percentage of chondrocytes that were dihydroethidium-positive was 35% above baseline 10 min after impact, and 65% above baseline 60 min after impact. Most positive cells were found within and near areas contacted directly by the impact platen. Rotenone, an electron transport chain inhibitor, was used to test the hypothesis that mitochondria contribute to superoxide release. Rotenone treatment significantly reduced dihydroethidium staining, which remained steady at 15% above baseline for up to 60 min postimpact. Moreover, rotenone reduced chondrocyte death in impact sites by more than 40%, even when administered 2 h after injury (p < 0.001). These data show that much of the acute chondrocyte mortality caused by in vitro impact injuries results from superoxide release from mitochondria, and suggest that brief exposure to free radical scavengers could significantly improve chondrocyte viability following joint injury.

The effect of incongruent instructions and consequences on imitation in retarded children

Three retarded boys served as subjects in a 13-phase experiment. In eight of these phases, the instructions administered by the experimenter before demonstrating a behavior and the consequences for imitative behavior were incongruent (the consequences were not those indicated by the instructions). Consequences rather than instructions controlled imitative behavior when (a) subjects were instructed not to imitate but received reinforcers if they imitated; (b) subjects were instructed to imitate but were differentially reinforced for other behavior; (c) subjects were instructed to imitate but were verbally reprimanded for imitation. Although subjects were highly imitative at the beginning of the study, when there was no reinforcement for imitation subjects gradually stopped imitating when instructed not to imitate. Instructions seemed to control imitative behavior when there was no reinforcement for imitation and subjects were instructed to imitate. These results indicated a need for further investigation of antecedent and consequent variables in imitation experiments and pointed out that certain techniques may be more efficient than others in eliminating well-established responses.

Holoprosencephaly and ectrodactyly: Report of three new patients and review of the literature

Holoprosencephaly (HPE) and ectrodactyly represent congenital malformations of the developing forebrain and developing digits, respectively. The combination of these conditions is rare, with only 15 cases known to date (12 previously reported, and 3 new cases described here). While the findings in these patients overlap with previously described genetic conditions, the similarity in phenotypes among these patients has led to the establishment of a at least one distinct syndrome: HPE, ectrodactyly, and bilateral cleft lip-palate syndrome (OMIM 300571). There has been great interest in identifying a genetic cause for the findings in patients with HPE and ectrodactyly; however the cause(s) of this rare association still remain unknown.

[Five years of renal trauma in a paediatric trauma center: new tools in the diagnostic and therapeutic process]

INTRODUCTION

There is general agreement in the conservative management of most renal traumas, but questions like the role of angiography are still controversial. Our objective is to review the paediatric renal trauma characteristics, propose a therapeutic protocol and suggest new therapeutic tools.

MATERIAL AND METHODS

Retrospective review of clinical records (epidemiology, diagnostic methods, renal injury grade according to the AAST Organ Injury Scale, treatment and follow up) of the paediatric renal injuries at Vail d'Hebron Hospital in the last 5 years. Outline of a diagnostic-therapeutic protocol consistent with the literature.

RESULTS

Since 2001, 18 cases of paediatric renal trauma have been diagnosed. Median of age was 10 years (range 2-17). Renal injury grade was: I (4), II (5), III (4), IV (4), V (1). Main mechanisms of injury were car and motorcicle accidents (4), fall (3), bicycle (3) and sports (3). There were different severity associated injuries in 10 patients. Abdominal exploration was normal in 6 cases, and in 5 (including the grade V injury) hematuria was absent or was microscopic. Mean hematocrit and hemoglobine were 34.5% y 11.8 g/dl. Abdominal CT was performed in all cases, detecting injuries that were unnoticed with ultrasound exploration. Complications were: renal artery pseudoaneurism (1), urinoma (1), uretero-pelvic joint disruption (1), arterial hypertension (3), renal colic (1). Management was: conservative in 13 cases, angiography in 4 (2 embolizations of bleeding vessels, 1 pseudoaneurism embolization, 1 placement of endovascular stents in an injury of the arterial intima), delayed surgery in 2 (1 nefrectomy, 1 uretero-pyeloplasty). All of them received prophylactic antibiotics; 10 had self-limited fever with negative cultures. Only in 2 cases DMSA at 6 months was inferior to 20%. There were no deaths.

CONCLUSIONS

In paediatric patients, there can be severe renal injuries despite absence of hematuria and a normal physical exam and hemogram. Abdominal CT with endovenous contrast is the keystone of diagnosis, and identifies vascular injuries that might need immediate treatment, like renal ischemia. Angiography is an important tool to consider in case of persistent bleeding or renal infarctation.

Rate of acute adverse events for narrow-band UVB and Psoralen-UVA phototherapy

BACKGROUND

Ultraviolet (UV) radiation therapies are commonly used to treat a wide range of dermatological conditions. However, no published data exist regarding the rate of acute adverse events occurring within the different UV therapy modalities.

AIM

The aim of this study was to determine the rate of acute adverse events experienced by patients receiving narrow-band UVB or photochemotherapy in 3 neighboring dermatology units.

METHOD

Standardized adverse event forms from all 3 units were retrospectively analysed over a 12-month period between October 2003 and September 2004. The treatments included were narrow-band UVB and systemic, bath and hand/foot PUVA.

RESULTS

A total of 8784 treatments were given over the study period. The total number of acute adverse events recorded for all phototherapy treatments was 70 (0.8%). The rates of acute adverse events for each treatment modality were 0.6% for narrow-band UVB, 1.3% for systemic PUVA, 1.3% for bath PUVA and 0.8% for hand/foot PUVA. Adverse events were due to patient non-compliance with standard operating procedures in 15 cases (21%) and operator error in 2 (3%). Only 4 of the acute adverse events were considered to be severe, accounting for 0.05% of all treatments.

CONCLUSIONS

The rates of acute adverse events with phototherapy in this analysis were low, in particular the rate of severe adverse events. The highest rate was seen with both systemic and bath PUVA. The number of adverse events resulting from operator error was low. These published rates for adverse events associated with narrow-band UVB and PUVA may help other units when analyzing their own rate of adverse events.

Antioxidants block cyclic loading induced chondrocyte death

Articular cartilage in congruous joints benefits from the moderate stresses and strains associated with normal cyclic loading. However, loading of joints with surface incongruities can lead to local stress and strain elevation at "step-off' sites where cartilage is not fully buttressed b ysurrounding matrix. Excessive stresses and strains predicted to occur at such sites may induce apoptosis, a process thought to promote cartilage degeneration and osteoarthritis (OA) through chondrocyte attrition. We hypothesized that the induction of apoptosis is mediated by oxidants, and that antioxidants can reduce elevated stress-induced chondrocyte attrition. To test this we exposed cylindrical cartilage explants from human articular cartilage to radially unconfined cyclic axial compression (3600 cycles, 1 Hz, 50% duty cycle) using two different physiologic loads (2MPa and 5 MPa). We found that 30% of chondrocytes in the superficial zone died within 24 hours of exposure to loading with 5 MPa axial compression, whereas mortality was limited to less than 15% with 2 MPa axial compression. Similarly, lactate accumulation in the medium was suppressed by compression with 5 MPa, but not 2 MPa. Approximately 80% of cell death induced by 5 MPa compression was blocked by pre-incubation of the explants in a variety of anti-oxidants including vitamin E, n-acetyl cysteine (NAC), and a superoxide dismutase mimetic (SOD). SOD and NAC also prevented the suppression of lactate secretion after 5 MPa compression. These observations support the hypothesis that the harmful effects of abnormal cyclic loading are mediated by oxidants and suggest that treatments to prevent OA may include methods of minimizing oxidative damage to chondrocytes.

Post-traumatic osteoarthritis: the role of stress induced chondrocyte damage

Post-traumatic osteoarthritis is the form of osteoarthritis (OA) that develops following joint injury. Although its end-stage is indistinguishable from idiopathic OA, many patients with post-traumatic OA are younger than those with idiopathic OA, and they have a well-defined precipitating insult. Clinical and experimental studies suggest that excessive acute impact energy or chronic mechanical overload cause the degeneration of the articular surface responsible for post-traumatic OA. Yet, the mechanisms by which excessive mechanical force causes OA remain unknown. For these reasons it has not been possible to develop effective methods of preventing or decreasing the risk of post-traumatic OA. We hypothesized that mechanical loading that exceeds the tolerance of the articular surface causes chondrocyte damage due to oxidative stress. Our in vitro tests of human articular cartilage samples showed that shear stress causes chondrocyte death and that anti-oxidants decrease the shear stress induced cell death. These observations suggest that specific patterns of loading are particularly damaging to articular surfaces and that improved treatments of joint injuries may include mechanical methods of minimizing shear stresses and biologic methods of minimizing oxidative damage.

Purification and physico-chemical characterisation of genetically modified phytases expressed in Aspergillus awamori

Two heterologous phytases from Aspergillus awamori and Aspergillus fumigatus obtained from submerged cultures of genetically modified fungal strains in addition to two commercially available phytase preparations (Allzyme and Natuphos phytases) were purified to homogeneity using a combination of ultrafiltration, gel filtration and ion exchange. The purified preparations were used in subsequent characterisation studies, in which Western Immunoblot analysis, pH and temperature optima, thermal stability and substrate specificity were assessed. A. fumigatus phyA phytase expressed in A. awamori exhibited activity over a broad pH range together with an increased temperature optimum, and slightly enhanced thermal stability compared to the other phytases tested, and is thus a promising candidate for animal feed applications. This particular phytase retains activity over a wide range of pH values characteristic of the digestive tract and could conceivably be more suited to the increasingly higher feed processing temperatures being utilised today, than the corresponding phytases from Aspergillus niger.

What can adaptive optics do for a scanning laser ophthalmoscope ?

By compensating for the aberrations in the eye that cause blur, the adaptive optics scanning laser ophthalmoscope (AOSLO) yields high-magnification, high-resolution, real-time images of the living human retina. Features as small as single cone photoreceptors can be resolved, single leukocytes are recorded in real time as they pass through the smallest retinal capillaries, and the optical sectioning capability can be used to visualize independent layers of the retinal tissue ranging from the nerve fiber layer, through the blood vessels to the photoreceptors. The use of AO technology not only enhances the breadth of applications of conventional SLOs, but it facilitates a host of new applications. Here we provide an overview of AOSLO performance and its applications, including two clinical examples. Finally, we preview two novel applications; one where the AOSLO is used to present AO-corrected stimuli directly onto the retina while simultaneously recording their exact retinal position, and a second application where AOSLO videos are used to provide very precise, high-frequency measures of eye movements.

Percutaneous Ultrasound-Guided Pancreas Allograft Biopsy: A Single-Center Experience

Percutaneous ultrasound-guided pancreas allograft biopsy is the preferred technique for evaluating pancreas allograft rejection. Experience from large centers has shown it to be safe and effective. We report our experience with 120 percutaneous allograft biopsies performed at a single center. Biopsy tissue was obtained in 54 patients. Thirty-three patients received simultaneous pancreas and kidney transplants, 14 received isolated pancreas transplants, and 7 received a pancreas transplant after kidney transplantation. Biopsies were performed by pancreas transplantation surgeons with the assistance of radiologists under ultrasound guidance using an Acuson XP 128/10 ultrasound machine. One hundred twenty allograft biopsies were performed in 54 patients. Twenty-seven (50%) patients underwent multiple biopsies. In 102 (85%) biopsies the specimens were adequate for examination. Eighteen (15%) biopsy samples had no pancreatic tissue and showed surrounding fat and small bowel. 1 (1.8%) patient bleeding developed that required transfusion of 3 units of packed red blood cells, but no surgical intervention was necessary. One (1.8%) patient had a pancreatic fistula, which healed with nonoperative management. Biochemical evidence of pancreatitis was noted in 5 (9.2%) patients, but none of these patients had clinical signs of pancreatitis. Percutaneous ultrasound-guided pancreas allograft biopsy is a safe procedure with a low complication rate and a high tissue yield for histopathologic examination.

Peristomal allergic contact dermatitis - case report and review of the literature

Allergic contact dermatitis (ACD) is a rare cause of peristomal skin problems. Only 23 cases have previously been reported in the literature. We report the case of a colostomy patient with a severe disabling blistering peristomal dermatitis. Patch testing to a British Contact Dermatitis Society standard series, medicaments and a plastics and glues series was negative. Patch testing to the patient's own products gave a positive reaction (+) at D2 and D4 to Dansac soft paste and Stomahesive paste. Further patch testing to the components of Dansac soft paste showed a positive (+) reaction at D2 and D4 to ester of polymethyl vinyl/maleic acid copolymer (Gantrez-ES) only. This is the first reported case of ACD due to Dansac soft paste. ACD to Gantrez has previously been reported but in different products. We also review the other previously reported cases of ACD causing peristomal dermatitis and stress the importance of patch testing in these cases, in particular to the patient's own products, as avoidance of identified allergens can have a large impact on the quality of life.

'Black henna' tattoos: an occult source of natural rubber latex allergy?

Temporary 'black henna' tattoos are an increasingly popular body decoration with a growing incidence of associated adverse events. We report the case of a 14 year old girl presenting with an acute allergic contact dermatitis to hair dyes. Some years previously she had a 'black henna' tattoo with prior application of a tacky transfer to the skin to outline the design followed some days later by an acute localised blistering reaction. Patch testing to an extended British Contact Dermatitis Society standard series showed relevant positive reactions to paraphenlyenediamine (PPD) and thiuram mix, as well as to several of the azo disperse dyes. We went on to perform prick testing to natural rubber latex (NRL), showing a positive reaction to the commercial HEP 100 concentration. We propose that through the initial acute reaction caused by PPD in the 'black henna' our patient was not only sensitized to PPD, but also to thiuram and natural rubber latex which may have been present in the tacky transfer applied prior to 'tattooing.' We would add that temporary 'black henna' tattoos may have more important consequences than previously thought on patients' future health by sensitization to NRL.

HIV infection presenting with duodenal tuberculosis

Extrapulmonary tuberculosis is a protean and often difficult to recognise infection. Gastrointestinal tuberculosis is a rare condition that mainly occurs in immunodeficient people. We report a case of duodenal tuberculosis, which presented with gastrointestinal symptoms, anaemia and hyponatraemia, in a patient with previously undiagnosed HIV infection.

Seventeen-year survivorship analysis of silastic metacarpophalangeal joint replacement

We reviewed the records and radiographs of 381 patients with rheumatoid arthritis who had undergone silastic metacarpophalangeal joint replacement during the past 17 years. The number of implants was 1336 in the course of 404 operations. Implant failure was defined as either revision or fracture of the implant as seen on radiography. At 17 years, the survivorship was 63%, although on radiographs two-thirds of the implants were seen to be broken. Factors which improved survival included soft-tissue balancing, crossed intrinsic transfer and realignment of the wrist. Surgery to the thumb and proximal interphalangeal joint had a deleterious effect and the use of grommets did not protect the implant from fracture.

Rheumatoid papules treated with dapsone

A patient with a long history of seropositive rheumatoid arthritis presented with a progressive papular eruption on the trunk. A skin biopsy showed a neutrophilic and palisaded granulomatous dermatitis compatible with rheumatoid papules. The eruption failed to respond to topical and systemic corticosteroids and the patient was treated with dapsone with complete resolution of the rash. Rheumatoid papules are a rare disorder seen in a variety of collagen vascular diseases. The literature concerning the treatment of rheumatoid papules is scanty. In this patient, dapsone was an effective treatment.

Cloning and expression of fungal phytases in genetically modified strains of Aspergillus awamori

In an effort to produce phytases cost-effectively, and to determine the efficiency of a novel expression system, the genes for Aspergillus awamori ( phyA) phytase and Aspergillus fumigatus ( phyA) phytase (a putative thermostable enzyme) were cloned and overexpressed in A. awamori. Regulation of phytase expression was achieved by separately placing the genes under the transcriptional control of the glucoamylase A ( glaA) promoter of A. awamori. A gene fusion strategy was employed that involved the insertion of a hexapeptide Kex-2 protease cleavage site between the native glucoamylase and heterologous proteins and allowed for the efficient secretion and processing of the resultant chimeric proteins produced in this system by an endogenous Kex-2 protease. The genes for both of the above-mentioned phytases have already been cloned; however, this is the first report of either of the two phytases being fused with the glucoamylase gene, placed under the transcriptional control of the glaA promoter and overexpressed in A. awamori. Following transformation of A. awamori with separate expression vectors (one for each phytase), induction of phytase expression in submerged culture was effected by utilisation of a starch-containing medium. Optimisation of heterologous protein production in small shake-flask cultures involved changes in medium constituents. Maximum phytase expression levels of 200 phytase units (PU) ml(-1) and 62 PU ml(-1) for recombinantly expressed phytases from A. awamori and A. fumigatus, respectively, were obtained in crude fermentation extracts. Subsequent process scale-up to 4 l batch fermentation yielded phytase production levels comparable to those obtained on small scale. The enzyme yields herein reported demonstrate that the expression system developed and the host strain utilised were capable of expressing phytase at levels comparable to, or exceeding, previously reported data.

The role of tenascin-C in adaptation of tendons to compressive loading

Although most tendon regions are subjected primarily to high tensile loads, selected regions, primarily those that directly contact bones that change the direction of the tendon, must withstand high compressive loads as well. Compressed tendon regions differ from regions subjected to primarily tensile loads: they have a fibrocartilaginous structure with spherical cells surrounded by a matrix containing aggrecan and collagen types I and II, in contrast regions not exposed to compression have a fibrous structure with spindle shaped fibroblasts surrounded by a matrix of dense, longitudinally oriented type I collagen fibrils. The spherical shape of cells in fibrocartilagenous regions indicates these cells are more loosely attached to the matrix than their spindle-shaped counterparts in fibrous regions, a feature that may help to minimize cell deformation during tendon compression. We hypothesized that expression of tenascin-C, an anti-adhesive protein, is part of the adaptation of tendon cells to compression that helps establish and maintain fibrocartilaginous regions. To test this hypothesis we compared tenascin-C content and expression in compressed (distal) versus uncompressed (proximal) segments of bovine flexor tendons. Immunohistochemistry and immunoblot analyses showed that tenascin-C content was increased in the distal tendon where it co-distributed with type II collagen and aggrecan. Tendon cells from the distal segments expressed more tenascin-C than did cells from the proximal segments for up to four days in cell culture, indicating that increased tenascin-C expression is a relatively stable feature of the distal cells. These observations support the hypothesis that tenascin-C expression is a cellular adaptation to compression that helps establish and maintain fibrocartilagenous regions of tendons.

Osteochondral repair of primate knee femoral and patellar articular surfaces: implications for preventing post-traumatic osteoarthritis

The risk of post-traumatic osteoarthritis following an intra-articular fracture is determined to large extent by the success or failure of osteochondral repair. To measure the efficacy of osteochondral repair in a primate and determine if osteochondral repair differs in the patella (PA) and the medial femoral condyle (FC) and if passive motion treatment affects osteochondral repair, we created 3.2 mm diameter 4.0 mm deep osteochondral defects of the articular surfaces of the PA and FC in both knees of twelve skeletally mature cynomolgus monkeys. Defects were treated with intermittent passive motion (IPM) or cast-immobilization (CI) for two weeks, followed by six weeks of ad libitum cage activity. We measured restoration of the articular surface, and the volume, composition, type II collagen concentration and in situ material properties of the repair tissue. The osteochondral repair response restored a mean of 56% of the FC and 34% of the PA articular surfaces and filled a mean of 68% of the chondral and 92% of the osseous defect volumes respectively. FC defect repair produced higher concentrations of hyaline cartilage (FC 83% vs. PA 52% in chondral defects and FC 26% vs. PA 14% in osseous defects) and type II collagen (FC 84% vs. PA 71% in chondral defects and FC 37% vs. PA 9% in osseous defects) than PA repair. IPM did not increase the volume of chondral or osseous repair tissue in PA or FC defects. In both PA and FC defects, IPM stimulated slightly greater expression of type II collagen in chondral repair tissue (IPM 81% vs. CI 74%); and, produced a higher concentration of hyaline repair tissue (IPM 62% vs. CI 42%), but IPM produced poorer restoration of PA articular surfaces (IPM 23% vs. CI 45%). Normal articular cartilage was stiffer, and had a larger Poisson's ratio and less permeability than repair cartilage. Overall Cl treated repair tissue was stiffer and less permeable than IPM treated repair tissue. The stiffness, Poisson's ratio and permeability of femoral condyle cast immobilized (FC CI) treated repair tissue most closely approached the normal values. The differences in osteochondral repair between FC and PA articular surfaces suggest that the mechanical environment strongly influences the quality of articular surface repair. Decreasing the risk of post-traumatic osteoarthritis following intra-articular fractures will depend on finding methods of promoting the osteochondral repair response including modifying the intra-articular biological and mechanical environments.

Co-localization of insulin-like growth factor binding protein 3 and fibronectin in human articular cartilage

OBJECTIVE

The anabolic cytokine insulin-like growth factor I (IGF-I) stimulates chondrocyte synthesis of matrix macromolecules and several lines of evidence suggest that it has a major role in maintaining articular cartilage and possibly in cartilage repair. Despite the apparent importance of IGF-I in articular cartilage metabolism and its potential importance in joint diseases, little is known about the regulation of IGF-I activity within the tissue. Insulin-like growth factor binding proteins (IGFBPs) bind IGF-I and can modify its activity. At least three IGFBPs are expressed by chondrocytes: IGFBP-3, -4 and -5. Localization of IGFPBs in the articular cartilage extracellular matrix (ECM) could create reservoirs of IGF-I within the articular cartilage ECM and thereby regulate local IGF-I levels. We hypothesized that ECM molecules bind and concentrate IGFPBs in the pericellular/territorial matrix.

DESIGN

Semi-quantitative immunohistological measures of co-localization were used to compare the spatial distribution of IGFBP-3, -4, and -5 with the distributions of three peri-cellularly-enriched matrix molecules fibronectin, tenascin-C, and type VI collagen in osteoarthritic and non-osteoarthritic human articular cartilage. Purified proteins were used in an agarose diffusion assay to compare IGFBP-3 binding to the same three matrix proteins.

RESULTS

IGFBP-3 associated with fibronectin in the pericellular/territorial matrix (approximately 40% co-localization) but not with tenascin-C, or type VI collagen (approximately 6% and approximately 15% co-localization respectively, P< 0.05). Neither IGFBP-4, nor IGFBP-5 were associated with any of the three ECM proteins (P< 0.05). In agarose diffusion assays IGFBP-3 interacted with fibronectin and heparan sulfate proteoglycan but not with type VI collagen or tenascin-C.

CONCLUSIONS

Direct binding between purified IGFBP-3 and fibronectin and the strong co-localization the two proteins in the cartilage matrix support the hypothesis that IGFPB-3 and fibronectin help regulate local IGF-I levels.

Cluster ions derived from sodium and potassium tetrafluoroborate and their collision induced dissociation in an ion trap mass spectrometer

Electrospray ionization was used to produce distributions of gas-phase cluster ions from solutions of sodium and potassium tetrafluoroborate. The majority of the cluster species followed the trend (MBF(4))(n)M(+), where M=Na and K. The values of n, for both salts, ranged from 1-15. Collision induced dissociation (MS/MS and MS(n)) in an ion trap mass spectrometer was used to determine the dissociation pathways for the cluster ions. The (NaBF(4))(n)Na(+) cluster ions fragmented via two pathways: (a) the loss of one or multiple neutral BF(3) molecules and (b) the loss of one or more NaBF(4) units. Of the two, the product ions corresponding to the loss of BF(3) units were more prominent. Unlike the Na salt, the (KBF(4))(n)K(+) cluster ions decomposed primarily by the loss of one or multiple KBF(4) units. Similar differences in dissociation behavior were observed when the heated transfer capillary, normally used to desolvate ions, was used to investigate cluster ion stability to thermal degradation and dissociation. The dissociation profiles (decrease in ion abundance with increasing activation amplitude) for several (NaF)(n)Na(+) and (KF)(n)K(+) cluster ions were measured and compared to probe the influence of the relative stability of the alkali fluorides (NaF and KF) on the dissociation behavior exhibited by the tetrafluoroborate cluster distributions. We found that the (NaF)(n)Na(+) cluster ions required higher activation amplitudes to induce fragmentation than the corresponding (KF)(n)K(+) species, indicative of stronger ionic bonding and higher gas-phase stability for the former. This in turn indicates that the reaction pathway involving only the loss of one or multiple units of BF(3), favored for the (NaBF(4))(n)Na(+) cluster series, but not for the analogous (KBF(4))(n)K(+) series, may be due to the high gas-phase stability of NaF, and relatively lower stability of KF, towards dissociation.

Training general practitioners in flexible sigmoidoscopy to screen for colorectal cancer

BACKGROUND

A screening programme to detect polyps or early carcinoma would significantly reduce the mortality and morbidity of colorectal cancer (CRC). The aims of the present study were to evaluate: (i) the feasibility of training general practitioners in flexible sigmoidoscopy (FS) for CRC screening; (ii) the acceptability of screening by faecal occult blood testing (FOBT) and FS in asymptomatic standard risk Australians aged over 50 years; and (iii) the yield of such screening.

METHODS

Subjects were recruited by general practitioner (GP) referral, newspaper advertisement or by a direct approach to retirement villages. Participants were mailed a FOBT kit and a prescreening questionnaire. Flexible sigmoidoscopy was performed by a GP supervised by an experienced endoscopist. Subjects then completed a second questionnaire. General practitioners were assessed after 50 unassisted procedures.

RESULTS

A total of 264 individuals contacted the study coordinator; 169 were screened. Screening was accepted well by the participants. Fifteen per cent of subjects had polyps and 4% had a positive FOBT. Training in FS was adversely affected by the availability of resources. Three GPs completed 50 unassisted procedures over a 15-month period, but none were able to reliably assess the distal bowel.

CONCLUSIONS

Although the three trainees and their supervisors did not consider that the GPs were adequately trained after 50 unassisted procedures, training was adversely affected by limited resources within the Victorian public hospital system. Screening by FOBT and FS was considered to be acceptable by the patients undergoing these procedures. Existing facilities are not adequate if GPs are to be trained in FS as part of a national CRC screening program.

Incidence rates for complete cusp fracture

OBJECTIVES

Although complete cusp fracture is acknowledged to occur frequently, incidence rates have been reported rarely. This study determined incidence rates for complete coronal cusp fracture per person and per tooth type.

METHODS

All fractures presenting among enrollees in a dental health maintenance organization using two geographically isolated clinics were noted for 105 days. For a sample of these enrollees, likelihood of attending the clinic in the event of a fracture was assessed through a telephone survey, and the at-risk status of all teeth was determined through a record survey. Incidence rates were calculated for persons, and for individual tooth types for all complete fractures and for non-carious complete fractures. In addition, for posterior teeth the distribution of fractured cusps, and the severity of fractures were examined.

RESULTS

Per-person incidence rates for complete coronal fractures for all teeth were 89.0 and 72.7 per 1000 person years, respectively, for all fractures and for non-carious fractures. The rates for all anterior and all posterior teeth were 10.2 and 69.9, respectively, for all non-carious fractures. In mandibular posterior teeth, lingual cusps fractured twice as frequently as facial cusps, while the opposite was true for maxillary premolars. Among maxillary molars, the mesiofacial and distolingual cusps fractured most frequently. The large majority of fractures exposed dentin (95%), while pulpal exposure occurred infrequently (3%). A minority of fractures extended below the gingival crest (24%) or the DEJ (25%).

CONCLUSIONS

This is the first report of fracture incidence rates for enumerated persons and teeth at risk and as such helps define the magnitude of the problem for dentists and their patients.

Social cognition and subclinical paranoid ideation

OBJECTIVE

A number of cognitive biases have been identified relevant to persecutory thought (e.g. exaggerated self-serving bias). Moreover, findings of increased depressed mood in conjunction with high levels of self-esteem have contributed to theories of persecutory ideation (e.g. Bentall, Kinderman, Kaney, 1994). Using a nonclinical sample, the present study sought to expand upon previous research by examining the linear relationship between persecutory ideation and multiple clinical and social cognitive variables.

DESIGN

A cross-sectional design was used. Correlational and multiple regression analyses were conducted.

METHOD

One hundred and ninety-three undergraduate students were administered a battery of questionnaires which assessed the following domains: Paranoid ideation, depression, social anxiety, self-monitoring, attributional style and self-esteem.

RESULTS

Higher levels of paranoid ideation were significantly associated with greater depressed mood, social anxiety and avoidance, evaluation apprehension, self-monitoring and lower self-esteem. There were no significant associations between paranoid ideation and attributional biases.

CONCLUSIONS

These findings suggest that mood, anxiety and perceptions of the self are related to paranoid ideation in a nonclinical sample. These findings are tempered, however, by studying a nonclinical sample and the self-report measures of paranoid ideation that might be assessing multiple aspects of paranoid thought (e.g. ideas of reference).

Births: preliminary data for 2000

OBJECTIVES

This report presents preliminary data for 2000 on births in the United States. U.S. data on births are shown by age, race, and Hispanic origin of mother. Data on marital status, prenatal care, cesarean delivery, and low birthweight are also presented.

METHODS

Data in this report are based on more than 96 percent of births for 2000. The records are weighted to independent control counts of births received in State vital statistics offices in 2000. Comparisons are made with 1999 final data.

RESULTS

The number of births rose 3 percent between 1999 and 2000. The crude birth rate increased to 14.8 per 1,000 population in 2000, 2 percent higher than the 1999 rate. The fertility rate rose 3 percent to 67.6 per 1,000 women aged 15-44 years between 1999 and 2000. The birth rate for teenagers, which has been falling since 1991, declined 2 percent in 2000 to 48.7 births per 1,000 females aged 15-19 years, another historic low. The rate for teenagers 15-17 years fell 4 percent, and the rate for 18-19 year olds was down 1 percent. Since 1991, rates have fallen 29 percent for teenagers 15-17 years and 16 percent for teenagers 18-19 years. Birth rates for all of the older age groups increased for 1999-2000: 1 percent among women aged 20-24 years, 3 percent for women aged 25-29 years, and 5 percent for women in their thirties. Rates for women aged 40-54 years were also up for 2000. The birth rate for unmarried women increased 2 percent to 45.2 births per 1,000 unmarried women aged 15-44 years in 2000, but was still lower than the peak reached in 1994. The number of births to unmarried women was up 3 percent, the highest number ever reported in the United States. However, the number of births to unmarried teenagers declined. The proportion of women who began prenatal care in the first trimester of pregnancy (83.2 percent) did not improve for 2000, nor did the rate of low birthweight (7.6 percent). The total cesarean rate rose for the fourth consecutive year to 22.9 percent, the result of both a rise in the rate of primary cesarean deliveries and a decline in the rate of vaginal births after previous cesarean delivery.

Nucleoside analogues as highly potent and selective inhibitors of herpes simplex virus thymidine kinase

A series of carboxamide derivatives of 5'-amino-2',5'-dideoxy-5-ethyluridine has been prepared as inhibitors of HSV-TK (herpes simplex virus thymidine kinase). The most potent compounds were derived from xanthene, thioxanthene and dihydroanthracene carboxylic acids. The lead compounds show subnanomolar IC(50) values against HSV TKs.

A sensitive, single-tube assay to measure the enzymatic activities of influenza RNA polymerase and other poly(A) polymerases: application to kinetic and inhibitor analysis

We describe a fast and robust new assay format to measure poly(A) polymerase (PAP) activity in a microtiter plate format. The new assay principle uses only natural nucleotide triphosphates and avoids a labour-intensive filtration step. A coupled enzymatic system combining PAP and reverse transcriptase forms the basis of the assay. The PAP generates a poly(A) tail on a RNA substrate and the reverse transcriptase is used to quantify the polyadenylated RNA by extension of a biotinylated oligo-dT primer. We demonstrate the principle of the assay using influenza virus RNA polymerase and yeast PAP as examples. A specific increase in the K(m) value for ATP and the observation of burst kinetics in the polyadenylation dependent, but not in the polyadenylation independent, assay suggest that a rate limiting step of influenza polymerase activity occurs after transcription elongation. Yeast PAP was used to validate the assay as an example of a template independent PAP. The new yeast PAP assay was approximately 100-fold more sensitive than the conventional TCA precipitation assay for yeast PAP, but the kinetic analysis of the PAP reaction gave similar results in both assays. The two enzymes show important differences with respect to inhibition by 3'-deoxy-ATP. Whereas the K(i) value for 3'-deoxy-ATP (105-117 microM) is similar to the K(m) value for ATP (186 microM) in the case of influenza RNA polymerase, the K(i) value for 3'-deoxy-ATP (0.4-0.6 microM) is approximately 100-fold lower than the K(m) value for ATP (50 microM) in the case of yeast PAP.

On the duration of spatial fluency measures

Various measures of spatial fluency have been developed and have been shown to be sensitive to right frontal lobe dysfunction. Patients with diffuse cerebral injuries (traumatic brain injury) also show impaired performance. Administration times for these tests range from three to five minutes. It is well known that longer tests provide more reliable data. In the present study, the base rates of unique designs and perseverative errors on the Five-Point Test were examined minute-by-minute for ten minutes, in a sample of healthy young adults (n=80). Contrasts between each minute showed significant decreases in number of unique designs to the ninth minute (significant at p<.001). Contrasts between each minute revealed significant increases (significant at p<.00l) in percentage of perseverative errors to the eighth minute. Data demonstrating the progressive decrease of unique designs and progressive increase of perseverative errors as a function of time have important implications for clinical practice. Optimal administration time is considered in the context of clinicians' objectives.

Births: final data for 1999

OBJECTIVES

This report presents 1999 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal characteristics (medical risk factors, weight gain, tobacco and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.

METHODS

Descriptive tabulations of data reported on the birth certificates of the 3.96 million births that occurred in 1999 are presented.

RESULTS

Overall birth and fertility rates changed less than 1 percent in 1999. Teenage birth rates fell 2 to 6 percent. The rate for women aged 20-24 years declined slightly, while rates for women in their late twenties and their thirties rose 2 to 3 percent each. The number of births to unmarried women, the birth rate, and the percent of births that were to unmarried women each rose 1 percent or less. Smoking by pregnant women overall dropped again, but rose among women aged 18-24 years. Improvements in prenatal care utilization continued. The cesarean delivery rate increased for the third year after declining for 7 consecutive years. The proportion of multiple births continued to rise; however, higher order multiple births (e.g., triplets, quadruplets) declined for the first time in over a decade, following increases of 13 percent per year during 1990-98. The percent low birthweight remained at 7.6 percent, while preterm births rose to 11.8 percent. These trends are in large part the result of increases in multiple births.

Telomere erosion and senescence in human articular cartilage chondrocytes

Aging and the degeneration of articular cartilage in osteoarthritis are distinct processes, but a strong association exists between age and the incidence and prevalence of osteoarthritis. We hypothesized that this association is due to in vivo replicative senescence, which causes age-related declines in the ability of chondrocytes to maintain articular cartilage. For this hypothesis to be tested, senescence-associated markers were measured in human articular chondrocytes from donors ranging in age from 1 to 87 years. These measures included in situ staining for senescence-associated beta-galactosidase activity, (3)H-thymidine incorporation assays for mitotic activity, and Southern blots for telomere length determinations. We found that senescence-associated beta-galactosidase activity increased with age, whereas both mitotic activity and mean telomere length declined. These findings indicate that chondrocyte replicative senescence occurs in vivo and support the hypothesis that the association between osteoarthritis and aging is due in part to replicative senescence. The data also imply that transplantation procedures performed to restore damaged articular surfaces could be limited by the inability of older chondrocytes to form new cartilage after transplantation.