Nondestructive measurements of implant-bone interface shear modulus and effects of implant geometry in pull-out tests

Push-out and pull-out tests are used for destructive evaluation of implant-bone interface strength. Because nondestructive mechanical tests would allow maintenance of an intact interface for subsequent morphological study, we developed such a test to determine the shear modulus of the interface by measuring the shear deformation of a thin layer adjacent to the implant. A polyurethane foam model was used to test the experimental setup on a group of nine cylindrical implants with three different lengths (15-48 mm) and three different diameters (5-9.7 mm). The shear modulus of the interface, as calculated from the pull-out test, was validated against the shear modulus of the foam derived from tensile tests. The two values of shear modulus were well correlated (R2 = 0.8, p < 0.001), thus encouraging further application of the setup for tests of implant-bone interface mechanics. In addition, we also examined the effects of implant length and diameter. The length of the implants had a significant influence on the interface shear modulus (p < 0.05), indicating that comparisons of the variable should only be made of implants with the same length. The length and diameter of the implants were not critical parameters for the ultimate fixation strength.

Learning about pain in preterm newborns

The first goal of the study was to explore whether preterm newborns can learn to predict painful stimulation. The second goal was to provide a description of physiological and behavioral responses to repeated heel-sticks over days. Preterm newborns, born between 28 and 32 weeks gestational age, were observed five times over a period of 2 weeks while undergoing heel-sticks. Infants' facial expressions, cardiac reactions, and movement durations were recorded before, during, and after the heel-stick procedure. On Tests 1, 3, and 5, the phlebotomist picked up the baby's leg and held it for 10 seconds before proceeding to the heel-stick. Infants showed significantly greater increase in heart rate during the leg pickup on Test 5 compared with Test 1. This increase in heart rate after 2 weeks of experience suggests that newborn infants learned to anticipate the painful stimulus. Infants also demonstrated reliable behavioral and cardiac reactions to the invasive part of the heel-stick, but no change was observed in reactivity over days. However, greater post-conceptional age (PCA) was associated with increased behavioral reactivity during heel-stick on Tests 4 and 5. The anticipatory heart rate increase during leg pickup highlights the preterm infant's early capacity to learn and react to experience in the neonatal intensive care unit. The lack of global change in reactivity to the invasive procedure over days illustrates the need to take into account specific factors such as PCA when investigating sensitivity to repeated pain experiences.

Mutational analysis of PHEX gene in X-linked hypophosphatemia

Hypophosphatemic rickets is commonly an X-linked dominant disorder (XLH or HYP) associated with a renal tubular defect in phosphate transport and bone deformities. The XLH gene, referred to as PHEX, or formerly as PEX (phosphate regulating gene with homologies to endopeptidases on the X-chromosome), encodes a 749-amino acid protein that putatively consists of an intracellular, transmembrane, and extracellular domain. PHEX mutations have been observed in XLH patients, and we have undertaken studies to characterize such mutations in 46 unrelated XLH kindreds and 22 unrelated patients with nonfamilial XLH by single stranded conformational polymorphism and DNA sequence analysis. We identified 31 mutations (7 nonsense, 6 deletions, 2 deletional insertions, 1 duplication, 2 insertions, 4 splice site, 8 missense, and 1 within the 5' untranslated region), of which 30 were scattered throughout the putative extracellular domain, together with 6 polymorphisms that had heterozygosity frequencies ranging from less than 1% to 43%. Single stranded conformational polymorphism was found to detect more than 60% of these mutations. Over 20% of the mutations were observed in nonfamilial XLH patients, who represented de novo occurrences of PHEX mutations. The unique point mutation (a-->g) of the 5'untranslated region together with the other mutations indicates that the dominant XLH phenotype is unlikely to be explained by haplo-insufficiency or a dominant negative effect.

Comparison of N-linked oligosaccharides of recombinant human tissue kallikrein produced by Chinese hamster ovary cells on microcarrier beads and in serum-free suspension culture

Glycosylation heterogeneity in recombinant human tissue kallikrein (r-HuTK) produced by Chinese hamster ovary (CHO) cells from microcarrier culture and from a serum-free suspension cell recycle process has been compared. Significant differences in the degree of sialylation were observed in glycoform distribution and oligosaccharide heterogeneity. High-performance liquid chromatography with a pellicular anion-exchange column under low pH eluant conditions was used to characterize the number and types of N-linked complex type oligosaccharides present. The oligosaccharides were released by N-glycanase and, after reduction, were resolved into a number of peaks containing one, two, three, and four sialic acids with an additional subfractionation based on the nature of the antennary structure. The microcarrier process resulted in a reduced amount of sialylated oligosaccharide species as compared to the suspension cell process. Removal of sialic acid followed by chromatography of the asialooligosaccharides under high pH anion-exchange conditions indicated that the same antennary structures were present but in slightly different relative amounts. The oligosaccharide profiles are indicative of a highly complex array of microheterogeneity present, encompassing mono-, di-, tri-, and tetrasialylated complex type oligosaccharides.

Ultrasound screening for hips at risk in developmental dysplasia. Is it worth it?

Between May 1992 and April 1997, there were 20,452 births in the Blackburn District. In the same period 1107 infants with hip 'at-risk' factors were screened prospectively by ultrasound. We recorded the presence of dislocation and dysplasia detected under the age of six months using Graf's alpha angle. Early dislocation was present in 36 hips (34 dislocatable and 2 irreducible). Of the 36 unstable hips, 30 (83%) were referred as being Ortolani-positive or unstable; 25 (69%) of these had at least one of the risk factors. Only 11 (31%) were identified from the 'at-risk' screening programme alone (0.54 per 1000 live births). Eight cases of 'late' dislocation presented after the age of six months (0.39 per 1000 live births). The overall rate of dislocation was 2.2 per 1000 live births. Only 31% of the dislocated hips belonged to a major 'at-risk' group. Statistical analysis confirmed that the risk factors had a relatively poor predictive value if used as a screening test for dislocation. In infants referred for doubtful clinical instability, one dislocation was detected for every 11 infants screened (95% confidence interval (CI) 8 to 17) whereas in infants referred because of the presence of any of the major 'at-risk' factors the rate was one in 75 (95% CI 42 to 149). Routine ultrasound screening of the 'at-risk' groups on their own is of little value in significantly reducing the rate of 'late' dislocation in DDH, but screening clinically unstable hips alone or associated with 'at-risk' factors has a high rate of detection.

Adrenal function in premature infants during inhaled beclomethasone therapy

OBJECTIVE

We tested the hypothesis that inhaled beclomethasone therapy for prevention of bronchopulmonary dysplasia does not cause adrenal suppression.

STUDY DESIGN

Infants receiving ventilatory support with birth weights </=1250 g and born at <33 weeks' gestation, age 3 to 14 days, were enrolled in a multicenter randomized trial to study the efficacy and safety of beclomethasone therapy versus placebo for prevention of bronchopulmonary dysplasia. Adrenal function was assessed on study day 21 (+/- 2 days) by determination of basal and stimulated plasma cortisol levels. Initially, cortisol response was assessed with insulin-induced hypoglycemia test (IIHT) (n = 63) until an interim analysis revealed insignificant cortisol response in both study groups. Thereafter, cosyntropin stimulation was used (n = 85).

RESULTS

Beclomethasone therapy was associated with lower median basal cortisol levels (5 microg/dL beclomethasone, 6 microg/dL placebo, P =.04). IIHT revealed insignificant change in cortisol response within each group. Cortisol response to cosyntropin stimulation was similar for each group (17 microg/dL beclomethasone, 18 microg/dL placebo, P =.86).

CONCLUSION

Beclomethasone therapy was associated with a small decrease in basal cortisol levels. There was no evidence of adrenal suppression in response to cosyntropin stimulation during beclomethasone therapy. Lack of cortisol response to hypoglycemia may reflect missed timing and/or decreased response of the premature infants' hypothalamic-pituitary-adrenal axis to hypoglycemia.

Positive effects of methylphenidate on hyperactivity are moderated by monoaminergic gene variants in children with autism spectrum disorders

Methylphenidate (MPH) reduces hyperactive-impulsive symptoms common in children with autism spectrum disorders (ASDs), however, response and tolerability varies widely. We hypothesized monoaminergic gene variants may moderate MPH effects in ASD, as in typically developing children with attention-deficit/hyperactivity disorder. Genotype data were available for 64 children with ASD and hyperactivity who were exposed to MPH during a 1-week safety/tolerability lead-in phase and 58 who went on to be randomized to placebo and three doses of MPH during a 4-week blinded, crossover study. Outcome measures included the Clinical Global Impression-Improvement (CGI-I) scale and the Aberrant Behavior Checklist (ABC-hyperactivity index). A total of 14 subjects discontinued the study because of MPH side effects. Subjects were genotyped for variants in DRD1-DRD5, ADRA2A, SLC6A3, SLC6A4, MAOA and MAOB, and COMT. Forty-nine percent of the sample met positive responder criteria. In this modest but relatively homogeneous sample, significant differences by DRD1 (P=0.006), ADRA2A (P<0.02), COMT (P<0.04), DRD3 (P<0.05), DRD4 (P<0.05), SLC6A3 (P<0.05) and SLC6A4 (P<0.05) genotypes were found for responders versus non-responders. Variants in DRD2 (P<0.001) and DRD3 (P<0.04) were associated with tolerability in the 14 subjects who discontinued the trial. For this first MPH pharmacogenetic study in children with ASD, multiple monoaminergic gene variants may help explain individual differences in MPH's efficacy and tolerability.

A systematic model improves hepatitis C virus birth cohort screening in hospital-based primary care

Despite national and local governing board recommendations in the United States of America to perform an HCV screening test in baby boomers, screening rates remain low. Our goal was to study the impact of an HCV screening and link-to-care programme with patient navigation in two New York City primary care practices. This was a 2-year prospective study of patients born between 1945-1965 ("baby boomers") with encounters at two primary care practices at the Mount Sinai Hospital between November 1, 2013 and November 30, 2015. Baseline HCV screening rates were collected for four months. A multifaceted intervention was sequentially implemented involving electronic alerts, housestaff education, data feedback and patient navigation. HCV screening rates and link to care, defined as attending an appointment with a viral hepatitis specialist, were compared before and after these interventions. There were 14 642 primary care baby boomer patients of which 4419 (30.2%) were newly screened during the study. There was a significant increase in HCV screening rates from 55% to 75% (P<.01) with an HCV seropositive rate of 3.3%. Factors associated with being HCV seropositive included older age (P<.01), male sex (P<.01), African American race (P<.01) and receiving care in the housestaff practice (P<.01). With patient navigation, 78 of 84 (93%) newly diagnosed HCV-infected persons were referred to a specialist and 60 (77%) attended their first appointment. A structured, multifaceted HCV screening programme using well-studied principles identifies a large number of undiagnosed baby boomers within hospital-based primary care and improves access to specialty providers in a timely manner.

Study of levosimendan during off-pump coronary artery bypass grafting in patients with LV dysfunction: a double-blind randomized study

Objectives:

Levosimendan is a calcium sensitizer drug which has been used in cardiac surgery for the prevention of postoperative low cardiac output syndrome (LCOS) and in difficult weaning from cardiopulmonary bypass (CPB). This study aims to evaluate perioperative hemodynamic effects of levosimendan pretreatment in patients for off-pump coronary artery bypass graft (OPCABG) surgery with low left ventricular ejection fractions (LVEF < 30%).

Materials and Methods:

Fifty patients undergoing OPCABG surgery with low LVEF (<30%) were enrolled in the study. Patients were randomly divided in two groups: Levosimendan pretreatment (Group L) and placebo pretreatment (Group C) of 25 each. Group L, patients received levosimendan infusion 200 μg/kg over 24 h and in Group C Patients received placebo. The clinical parameters measured before and after the drug administration up to 48 h were heart rate (HR; for the hour after drug infusion), cardiac index (CI), and pulmonary capillary wedge pressure (PCWP). The requirement of inotropes, intraaortic balloon pump (IABP), CPB, intensive care unit (ICU) stay, and hospital stay were also measured.

Results:

The patients in group L exhibited higher CI and PCWP during operative in early postoperative period as compared to control group C. Group L also had a less requirement for inotropes, CPB support and IABP with shorter ICU stay as well as hospital stay.

Conclusion:

Levosimendan pretreatment (24 h infusion) in patient for OPCABG with poor LVEF shows better outcomes and hemodynamics in terms of inotropes, CPB and IABP requirements. It also reduces ICU stay.

Serratia marcescens outbreak associated with extrinsic contamination of 1% chlorxylenol soap

OBJECTIVES

To determine risk factors for Serratia marcescens infection or colonization, and to identify the source of the pathogen and factors facilitating its persistence in a neonatal intensive-care unit (NICU) during an outbreak.

DESIGN

Retrospective case-control study; review of NICU infection control policies, soap use, and handwashing practices among healthcare workers (HCWs); and selected environmental cultures.

SETTING

A university-affiliated tertiary-care hospital NICU.

PATIENTS

All NICU infants with at least one positive culture for S marcescens during August 1994 to October 1995. Infants who did not develop S marcescens infection or colonization were selected randomly as controls.

RESULTS

Thirty-two patients met the case definition. On multivariate analysis, independent risk factors for S marcescens infection or colonization were having very low birth weight (< 1,500 g), a patent ductus arteriosus, a mother with chorioamnionitis, or exposure to a single HCW. During January to July 1995, NICU HCWs carried their own bottles of 1% chlorxylenol soap, which often were left standing inverted in the NICU sink and work areas. Cultures of 16 (31%) of 52 samples of soap and 1 (8%) of 13 sinks yielded S marcescens. The 16 samples of soap all came from opened 4-oz bottles carried by HCWs. DNA banding patterns of case infant, HCW soap bottle, and sink isolates were identical.

CONCLUSIONS

Extrinsically contaminated soap contributed to an outbreak of S marcescens infection. Very-low-birth-weight infants with multiple invasive procedures and exposures to certain HCWs were at greatest risk of S marcescens infection or colonization.

Alport's syndrome: risk of glomerulonephritis induced by anti-glomerular-basement-membrane antibody after renal transplantation

Two patients with Alport's syndrome developed glomerulonephritis induced by anti-glomerular-basement-membrane (anti-GBM) antibody after renal transplantation. One patient presented at 5 months after transplantation the second patient 18 months after transplantation. Both grafts failed and the patients returned to dialysis. Our observations suggest that the patients with Alport's syndrome are at risk of developing anti-GBM antibody type glomerulonephritis in the transplanted kidney. This does not occur in the early period after transplantation, probably because of heavy immunosuppression.

Ultrasound screening for hips at risk in developmental dysplasia

Between May 1992 and April 1997, there were 20 452 births in the Blackburn District. In the same period 1107 infants with hip ‘at-risk’ factors were screened prospectively by ultrasound. We recorded the presence of dislocation and dysplasia detected under the age of six months using Graf’s alpha angle. Early dislocation was present in 36 hips (34 dislocatable and 2 irreducible). Of the 36 unstable hips, 30 (83%) were referred as being Ortolani-positive or unstable; 25 (69%) of these had at least one of the risk factors. Only 11 (31%) were identified from the ‘at-risk’ screening programme alone (0.54 per 1000 live births). Eight cases of ‘late’ dislocation presented after the age of six months (0.39 per 1000 live births). The overall rate of dislocation was 2.2 per 1000 live births.

Only 31% of the dislocated hips belonged to a major ‘at-risk’ group. Statistical analysis confirmed that the risk factors had a relatively poor predictive value if used as a screening test for dislocation. In infants referred for doubtful clinical instability, one dislocation was detected for every 11 infants screened (95% confidence interval (CI) 8 to 17) whereas in infants referred because of the presence of any of the major ‘at-risk’ factors the rate was one in 75 (95% CI 42 to 149).

Routine ultrasound screening of the ‘at-risk’ groups on their own is of little value in significantly reducing the rate of ‘late’ dislocation in DDH, but screening clinically unstable hips alone or associated with ‘at-risk’ factors has a high rate of detection.

Tubulin stimulates adenylyl cyclase activity in C6 glioma cells by bypassing the beta-adrenergic receptor: a potential mechanism of G protein activation

While the cytoskeleton is known to play several roles in the biology of the cell, one role, which has been revealed only recently, is that of a participant in the signal transduction process. Tubulin binds specifically to the alpha subunits of Gs (stimulatory GTP-binding regulatory protein of adenylyl cyclase), Gi1 (inhibitory protein of adenylyl cyclase), and Gq and transactivates those molecules through direct transfer of GTP. The relevance of this transactivation process to G proteins which are normally activated by a neurotransmitter-occupied receptor is the subject of this study. C6 glioma cells, made permeable with saponin, retained tight coupling between Gs and the beta-adrenergic receptor. Although 5-guanylylimidodiphosphate (GppNHp) was incapable of activating Gs (and subsequently, adenylyl cyclase) in the absence of agonist, tubulin with GppNHp bound (tubulin-GppNHp) activated adenylyl cyclase with an EC(50) of 30 nM. Desensitization of beta-adrenergic receptors by isoproterenol exposure had no effect on the ability of tubulin-GppNHp to activate Gs and adenylyl cyclase. When the photoaffinity GTP analog, azidoanilido GTP (AAGTP; P3(4-azidoanilido)-P1-5'-GTP), was added to C6 membranes or permeable C6 cells, it was only weakly incorporated by G alpha s in the absence of isoproterenol. When the same concentration of dimeric tubulin with AAGTP bound was introduced, AAGTP was transferred from tubulin to G alpha s, activating the latter species. Similar 'preferential' activation of G alpha s by tubulin-AAGTP versus the free nucleotide was seen using purified components. Thus, membrane-associated tubulin may serve to activate G alpha s, independent of signals not normally coupled to that protein. Tubulin may act as an agent to link a variety of membrane-associated signalling systems.

Oral submucous fibrosis in a 11-year-old Bangladeshi girl living in the United Kingdom

A case of oral submucous fibrosis occurring in a 11-year-old Bangladeshi girl is presented. This paper reviews the aetiology, clinical presentation and treatment modalities of oral submucous fibrosis. This case highlights the link between oral submucous fibrosis and the regular use of areca-nut (paan) and the newer transcultural oral tobacco products. This association has been reported among children resident in the Indian sub-continent but is unrecorded for United Kingdom residents. The case report underlines the danger that children face with products which are clearly targeted at them by the tobacco industry.

Ferromagnetic high-permeability alloy alone can provide sufficient low-frequency and eddy-current shieldings for biomagnetic measurements

A low cost, two-shell ferromagnetic shielded room large enough for a person to enter and prepare experiments was constructed for biomagnetic measurements. No aluminium or copper shell was used for eddy-current shielding. A high-permeability nickel-iron-molybdenum alloy (1.57 mm thick) was used for both ferromagnetic and eddy-current shieldings. The shielding factor was 60 dB at dc and 40 dB between 0.1 Hz and about 3 Hz. The eddy-current shielding due to the alloy alone provided a shielding factor of 55 dB at 30 Hz and 66 dB at 60 Hz. The shielding factor was sufficiently high in all the frequency range for biomagnetic measurements with a first-order superconducting gradiometer.

Physician estimate of antiretroviral adherence in India: poor correlation with patient self-report and viral load

Adherence to antiretroviral therapy (ART) is critical in maintaining viral suppression and minimizing resistance in HIV-infected patients. We compared physician estimates of their patients' ART adherence with participant's self-reported adherence to determine patient-provider agreement and identify correlates of discordance in three private clinics in Mumbai, India. Between December 2004 and April 2005, 277 persons receiving ART at three private clinics in Mumbai, India, were interviewed regarding adherence to ART using the Adult AIDS Clinical Trials Group questionnaire. Physicians were also asked to assess their patients' adherence. Quantitative HIV-1 RNA level was determined for 200 participants. Agreement between provider estimate of adherence and participant self-report was low, kappa = 0.058 (95% confidence interval [CI] 0.011-0126). Of 200 participants whose viral load was obtained, viral suppression was associated with participant self-reported adherence (odds ratio [OR] 3.08; 95% CI 1.65-5.74; p < 0.05), but not with provider estimated adherence (OR 1.2; 95% CI 0.67-2.14; p = 0.54). Cost of ART was positively associated with physician underestimation of participant adherence and older age was negatively associated. No independent correlates of physician overestimation of participant adherence were found. There was poor agreement between physician estimate of adherence and patient self-report. Providers should avoid using their own assessment of patient ART adherence. Instead, providers should rely on effective and validated measures, especially when viral load or drug level monitoring are not readily available.

A pharmacokinetic study to evaluate the absolute bioavailability of triamcinolone acetonide following inhalation administration

Triamcinolone acetonide is a glucocorticoid administered by oral inhalation in the management of asthma. With oral inhalation of glucocorticoids, systemic absorption can come from oropharyngeal, gastrointestinal, or airway deposition of the drug. The objectives of this study were to determine the absolute bioavailability of triamcinolone acetonide following inhalation administration and to delineate the airway contribution of triamcinolone acetonide absorption relative to the absolute bioavailability. All subjects received a 5-minute 400 mcg intravenous infusion of triamcinolone acetonide and a single 800 mcg dose of inhaled triamcinolone acetonide with and without oral charcoal administration in a randomized three-way crossover fashion. The oral charcoal allowed for isolating the pulmonary component of absorption by adsorbing the oropharyngeal and gastrointestinal deposited drug. The mean (+/- SD) absolute bioavailability value for inhaled triamcinolone acetonide was 25% (8.75%). Delineation of the airway contribution of triamcinolone acetonide absorption showed that 10.4% of an inhaled dose is absorbed as triamcinolone acetonide from the lungs. Mean (+/- SD) total body clearance was rapid at 0.57 (0.12) L/hr/kg. The mean (+/- SD) apparent volume of distribution following the intravenous dose was a low 1.96 (0.31) L/kg. No significant differences were noted in the apparent terminal elimination half-life of triamcinolone acetonide (approximately 2.4 hr) between treatments.

A rural population based case-control study of senile cataract in India

PURPOSE

Senile cataract contributes to 75% of blindness in India and there is a growing backlog of cataract cases needing surgery. The present study seeks clues to the etiology of senile cataract, so that strategies to prevent or even delay cataract formation could be planned.

METHODS

Using a community based case-control design, 258 cases & 308 controls from one centre and 301 cases & 591 controls from another were studied. The subjects were from rural areas and were aged 40-60 years. Logistic regression analysis technique was employed to study the associations between senile cataract and various variables.

RESULTS

Systolic blood pressure, duration of exposure to sunlight per day were associated with senile cataract in both the centres (OR = 1.4 & 1.5 for systolic BP and 1.6 & 1.4 for exposure to sunlight). Utilization of rice gruel (OR = 0.5), duration of exposure to fire & dust per day (OR = 1.8), family history of cataract (OR = 5.0), use of cheap cooking fuels (OR = 1.8), increased height (OR = 0.7) and increased number of hours of work per day (OR = 0.7) were other variables that showed significant association in either of the centres.

CONCLUSION

Senile cataract appears to have a multi factorial etiology. Though the study provided some clues to the etiology of senile cataract, further studies are needed to know the specific role of these factors in the causation of cataract, so that any preventive or control measures could be initiated in the community. Till such time, we have to fall back on the available surgical approach in control of senile cataract.

Current experience with renal transplantation in older patients

Older patients (greater than 50 years old) are generally considered to be at high risk in renal transplantation, particularly those receiving cadaveric kidneys. The outcome in 53 older patients (mean age, 54 years; range, 50 to 64 years) receiving transplants between January 1, 1980 and December 31, 1986 and followed through June 30, 1987 were analyzed. Before 1984, immunosuppression consisted of azathioprine and prednisone (AP); thereafter, triple therapy (TT)--low-dose cyclosporine, azathioprine, and prednisone--was used. The overall 1-, 3-, and 5-year actuarial patient survival was 87%, 84%, and 84%, respectively. Survival for living related donor (LRD) transplant recipients was 100%, 92%, and 92%; survival for cadaveric (CAD) transplant recipients was 81%, 81%, and 81%. The overall graft survival was 74%, 66%, and 66% at 1, 3, and 5 years, respectively; graft survival was 88%, 81%, and 81% for LRD transplant recipients and 68%, 58%, and 58%, for CAD recipients. The patient and graft survival rates were better in the TT group than in the AP group. Eight patients died after transplantation; six within the first year. The causes of patient death were infection (50%), cardiac (25%), and malignancy (25%). Rejection (56%) and patient death (38%) accounted for most of the grafts lost. Patient and graft survival rates in diabetic patients were not significantly different from survival rates in nondiabetic patients. Results in recipients of ten secondary and one tertiary transplant were poor, with only four of 11 grafts functioning at 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)