0744 Cardiac Safety Profile of Pitolisant in Patients with Narcolepsy

Introduction

Cardiovascular diseases are comorbid in patients with narcolepsy. Cardiovascular adverse effects are of concern with narcolepsy medications because of this comorbidity and most patients require lifelong pharmacotherapy. Pitolisant, a selective histamine 3 (H3)-receptor antagonist/inverse agonist, increases histamine transmission in the brain. In a QT study of healthy volunteers, pitolisant (35.6 mg/day) led to a mean increase of 4.2 msec in QTc interval. This analysis further characterized the cardiac safety of pitolisant (maximum dose, 35.6 mg/day) in adults with narcolepsy.

Methods

Data were obtained from a pooled analysis of 2 randomized, placebo-controlled, 7- or 8-week studies and from a 12-month, open-label study.

Results

Pooled analysis included 166 patients (pitolisant, n=85; placebo, n=81). Mean change in heart rate from baseline to end-of-treatment was -0.5 beats/min with pitolisant and -0.2 beats/min with placebo (LS mean difference, -0.4; P=0.744). Mean change was also similar for pitolisant versus placebo in systolic (LS mean difference, 0.0; P=0.983) and diastolic (LS mean difference, -0.6; P=0.552) blood pressure, as was mean change in QTc interval (LS mean difference, 0.4; P=0.911). Cardiac adverse events with pitolisant included heart rate increase (n=4), right bundle branch block (n=1), sinus tachycardia (n=1), and palpitations (n=1), and with placebo included blood pressure increase (n=1). In the long-term study, mean change from baseline in QTc interval was 3.1 msec at Month 6 (n=70) and 6.1 msec at Month 12 (n=67); 3 patients had a postbaseline increase >60 msec but none had QTc >500 msec.

Conclusion

In this analysis, no cardiac safety signals were observed during treatment with pitolisant administered up to the maximum recommended dose. Because concomitant use of pitolisant with other drugs known to increase the QT interval may add to the QT effects of pitolisant, avoid use of pitolisant in combination with these medications.

Support

Bioprojet Pharma and Harmony Biosciences, LLC.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Zur Struktur des Enols von Benzoylaceton / On the Structure of the Enol of Benzoylacetone

A low temperature X-ray study of the enol of benzoylacetone indicates fixed positions of the C and O atoms within the enolic ring system and an extensive bond delocalisation over these atoms. The distribution of electron density between the two oxygen atoms shows that the enolic hydrogen is spread over a wide range. This is in accordance with a structural model proposed by de la Vega, whereupon the C and O atoms are kept fixed in their average positions during a tunneling process of the hydrogen between the two oxygen atoms. With this conception, the chemical shifts in the 17O and 13C NMR spectra, the 13C13C spin coupling constants and the temperature independance of these values can be explained.

Abstract P2-11-16: Cardiac Morbidity After Adjuvant Chemotherapy (CT) for Early Breast Cancer in the Community Setting

Cardiac morbidity after exposure to CT is a known and previously described risk. Anthracycline exposure can be complicated by acute or chronic cardiac toxicity. Trastuzumab exposure is largely associated with acute and reversible cardiac morbidity.

Methods: We retrospectively queried the electronic health record (EHR) from our network of community oncology practices, iKnowMed, for patients (pts) diagnosed with Stage I-III breast cancer (BC) from 2007–2010 with at least 5 visits and follow-up (f/u) through 2012. We stratified this group by CT utilization (yes/no), regimen type, age, and characterized the incidence of cardiac disease or initiation of cardiac medication through the f/u period to determine the association of cardiac disease or treatment with CT utilization. Cardiac diseases analyzed included congestive heart failure, valvular and ischemic heart disease, arrythmias, and hypertension. Cardiac medications included beta blockers, angiotensin-converting-enzyme inhibitors, angiotensin receptor II blockers, loop and thiazide diuretics. Hazard ratios by prespecified risk parameters were then analyzed by multivariate analysis for all pts who did not have cardiac disease preceding their diagnosis of BC.

Results: We identified 20,900 pts with a median f/u of 3.2 yrs (1.4–5.4). 11,295 (54%) pts received adjuvant CT and 9,605 (46%) did not. Median age at diagnosis in the CT-treated arm and non CT-treated arm was 54 and 64 yrs, respectively (p &lt; 0.0001). Among both the non-CT and CT-treated group, the baseline prevalence of cardiac disease was 14%. Among the CT-treated group, 3475 pts or 31% (95% CI, 30 %−32%) had or developed cardiac disease within the study period. In the non-CT group, 3790 pts or 39% (95% CI, 38%−40%) had or developed cardiac disease with the study period (p &lt; 0.01). Receiving CT conveyed a lower risk of cardiac morbidity overall, HR 0.86 (p &lt; 0.01). Incidence of cardiac disease was higher among pts who were in the non-CT treated arm (39%) than among the various CT-treated arms: anthracycline and trastuzumab (30%), anthracycline without trastuzumab (26%), non-anthracycline with trastuzumab (33%), and non-anthracycline without trastuzumab (34%). Incidence of cardiac disease increased proportionally over time in all age groups as expected in both cohorts.

Different bone loading patterns due to fixation of three-unit and five-unit implant prostheses

BACKGROUND

It has been considered that implant prostheses ought to display passive fit. The objective of this finite element analysis (FEA) was to simulate the bone loading resulting from the fixation of implant-supported three and five-unit fixed partial dentures (FPDs).

METHODS

Based on a patient case, six different FPD-groups were fabricated using either two or three implants for support. Strain gauges on the pontics of the prostheses were used for in vivo measurements. Based on the values obtained, bone loading models were simulated using three-dimensional finite element analysis and the results obtained were represented as von Mises equivalent stress.

RESULTS

The mean strain (epsilon) values ranged from 15 micro epsilon to 170 micro epsilon for the three-unit FPDs and from 32 micro epsilon to 302 micro epsilon for the five-unit FPDs. FEA revealed von Mises stresses up to 30 MPa in the cortical area, while in trabecular bone values up to 5 MPa were observed. Static implant loading of similar magnitude can be provoked through 200 N axial load.

CONCLUSIONS

Although the in vivo measured strain levels (epsilon) were of higher magnitude for the five-unit prostheses, FEA revealed bone loading of comparable magnitude for both three- and five-unit FPDs. Multi-unit prostheses may demonstrate greater inaccuracies compared with single implant restorations, but due to the absence of moment loading the multi-implant configuration appears to compensate for the higher strain development.

A time-dependent healing function for immediate loaded implants

Current interest in immediate dental implant loading has grown due to a number of clinical advantages this treatment modality offers. To obtain a deeper insight into the changing mechanical properties during the healing phase, results from removal torque tests are used in a biomechanical model. The ultimate removal torques, which depend on healing time, are described by a time-dependent healing function. The bone behavior is modeled using an elastic law with damage. The evolution of damage is represented with an incremental equation with an initial damage value and two material parameters. The nonlinear relationship between the torque and the angle of rotation up to the ultimate torque can be calculated. By changing the elastic parameter in the elastic damage law, the remodeling process can be characterized. In a further step, the elastic parameters and the limits for shear stress from the biomechanical model for the removal torque will be used in an FE analysis in order to obtain information on the axial loading limits of a dental implant at different healing times.

[A rare cause of subacute parotitis. The pathogenetic role of crystals from an infarcted Whartin's tumour?]

The etiology of a subacute inflammatory swelling in the area of the right parotid gland in a 62-years old man could not be resolved clinically. The histomorphological examination of the surgical specimen showed an intraglandular area of predominantly chronic histiocytic inflammation with foreign body reaction in the intimate neighbourhood of a small, subtotally infarcted Warthin's tumour. Not birefringent spindle-shaped crystals could be demonstrated both within the parotitis or intraluminally in vital parts of the Warthin's tumour. In terms of the possible causes of the severe intraglandular inflammation, all arguments favour a primary infarction of the Warthin's tumour with the release of intraluminal preformed crystals which secondarily induce a massive inflammation with foreign body reaction, corresponding to the clinical presentation of a subacute parotitis.

Use of subatmospheric pressure therapy to prevent burn wound progression in human: first experiences

Thermal trauma causes two different types of injuries within the burn wound. First, an immediate and irreversible injury, and, second, a delayed and partly reversible injury. It is a very common observation in burned patients that areas that initially seemed to be partial thickness burns have to be regarded as full thickness within the next day or days. The impairment of blood flow within the zone of stasis is due to the impairment of the vascular patency at the microvascular level. This progression is closely correlated to the degree of oedema formation. The aim of the study was to demonstrate that applied, controlled subatmospheric pressure is useful to prevent the progression of partial thickness burn injuries. Therefore, seven patients (mean age, 44.2 years; S.D., 22.4 years) with bilateral partial thickness hand burns were included into this treatment protocol. The more intense injured hand was treated with controlled applied subatmospheric pressure (V.A.C. (ATS)), the other and less injured hand conservatively by use of silver sulphadiazine creme. In the V.A.C.-treated hand a massive hyperperfusion was observed, being a possible reason for the prevention of burn progression. Moreover, a noteworthy amount of fluid was removed from the burn wound and a clinically obvious oedema reduction was observed in comparison to the contralateral side. In summary, we are of the opinion, that patients with partial thickness or mixed thickness burn may benefit from the application of subatmospheric pressure by reducing oedema formation and increasing perfusion.

The influence of dressings and ointments on the qualitative and quantitative evaluation of burn wounds by ICG video-angiography: an experimental setup

Burn wound depth is difficult to determine. Even for experienced investigators the exact differentiation between superficial and deep dermal burns is not always possible. Therefore, methods for objective and reproducible measurements estimating the depth of burn wounds are of great clinical interest. One technique that appears to be able to differentiate between superficial and deep dermal burn wounds is ICG video-angiography. Since burn wounds are often covered with dressings and ointments or soiled with blood, it is necessary to evaluate the influence of these substances on ICG video-angiography and its performance as a measurement method. The most commonly used ointments and dressings were tested. All studied substances had a massive influence on ICG video-angiography and its measurements. They caused decreases by absorption of up to 63 +/- 36% and thereby falsely reported deeper burn wounds. The results of this study, suggest that in clinical practice, all dressings, ointments and blood should be completely removed at least 10 min prior to measurement by ICG video-angiography to gain exact and reproducible results.

Indocyanine green video angiographies help to identify burns requiring operation

The key decision in the treatment of thermal injuries is the determination of the depth of the burn wound and the resultant decision on treatment options. The trend in the treatment of deep dermal and full thickness burns is toward very early excision and grafting to reduce the risk of infection, decrease scar formation, shorten hospital stay, and thereby reducing costs. Traditionally, this has involved serial clinical examinations, which involves primarily subjective judgment. Various objective examination techniques, supplementing the clinical diagnosis, have been suggested, but none has yet achieved widespread clinical acceptance. It has frequently been postulated that the blood flow in injured tissue indicates the extent of tissue damage. In this study, the clinical and scientific impact of indocyanine green (ICG) video angiography was tested in 20 patients. A wide range of depth of injury and etiology was included and analyzed. In all cases considered, video angiography was possible. The measurements and observations correlated well with the actual burn depth, which was assessed clinically (pre- and intraoperative assessment) and histologically (biopsies). In conclusion, ICG video angiography seems to be a practical method to describe vascular patency in a burn wound. The results indicate that ICG fluorescence angiography is a practical, accurate, and effective adjunct to clinical methods for estimating burn wound depth and thereby to assist in the rational assessment of treatment options. Furthermore, it allows an objective, qualitative and quantitative observation of the dynamic changes in burn wound depth, which are observed during the acute post-burn period, thereby indicating optimal timing of the first operation.

Hydrocortisone improved haemodynamics and fluid requirement in surviving but not non-surviving of severely burned patients

Recent studies have shown that administration of hydrocortisone may lead to a reduction of catecholamines and to an improved outcome in septic patients. However, there are no data on the use of hydrocortisone in burn patients although in these patients reduction of vasopressors might be even more crucial for outcome due to improvement of skin perfusion. This study presents the first results on the impact of hydrocortisone administration in norepinephrine dependent severely burned patients. In a prospective cohort study fourteen consecutive severely burned patients received, 12h after norepinephrine dependency, a hydrocortisone bolus of 100mg followed by 0.18mg/(kgh) hydrocortisone. The course of the necessary norepinephrine dose, as well as the fluid balance was documented 12h prior and after the first dosage of hydrocortisone. Statistical analysis showed an unexpected increase of the required norepinephrine dosage. A statistical post hoc evaluation of surviving and non-surviving patients revealed a significant increase of norepinephrine in non-survivors whereas in survivors it was possible to reduce norepinephrine significantly. Furthermore, the median fluid requirement of surviving patients could be significantly reduced whereas in the group of non-survivors there was no change of volume needed. Our data suggests that hydrocortisone might be useful in selected patients with severe burn injuries. However, patients not responding to hydrocortisone administrations seem to have a poor prognosis. Our findings are in contrast to previously published data on septic patients, in whom hydrocortisone administration resulted in a reduction of norepinephrine. In burned patients the severity of trauma seems to have more profound influence on the pathophysiological mechanism of sepsis. Due to the high number of non-responders, the potential immune suppression and impaired wound healing caused by the side effects of hydrocortisone, further selection criteria seem to be necessary. A short ACTH-test might be considered prior to hydrocortisone administration to select patients who might benefit from this therapy. In summary, further prospective controlled studies will be necessary to establish hydrocortisone in the routine therapy of severely burned patients.

A comparison of propofol and sevoflurane anaesthesia: effects on aortic blood flow velocity and middle cerebral artery blood flow velocity

We compared systemic (aortic) blood flow and cerebral blood flow velocity in 30 patients randomly allocated to receive either propofol or sevoflurane anaesthesia. Cerebral blood flow velocity (CBFv) was measured in the middle cerebral artery using transcranial Doppler. Systemic blood flow velocity (SBFv) was measured in the aorta using transthoracic Doppler sonography at the level of the aortic valve. Bispectral index (BIS) was used to measure the depth of anaesthesia. Measurements were made in the awake patient and repeated during propofol or sevoflurane anaesthesia, with BIS measurements of 40-50. The effects of SBFv on CBFv were estimated by calculating the cerebral/systemic blood flow velocity-index (CsvI). A CsvI value of 100 indicating a 1 : 1 relationship between CBFv and SBFv. The results demonstrated that propofol anaesthesia produced a significantly greater reduction in CsvI than did sevoflurane anaesthesia [propofol: 60 (19); sevoflurane: 83 (16), p = 0.009, t-test]. This suggests a direct reduction in CBFv independent of SBFv during propofol anaesthesia. The greater reduction of CBFv occurring during propofol anaesthesia may be due to lower cerebral metabolic demand compared with sevoflurane anaesthesia at comparable depths of anaesthesia.

Overdenture attachment selection and the loading of implant and denture-bearing area. Part 1: In vivo verification of stereolithographic model

Preliminary to a study investigating the force transfer from osseointegrated dental implants to the surrounding bone via various types of overdenture attachment, a stereolithographic model (SL-model) was constructed and compared to an in vivo situation in order to confirm the validity of the modeling technique for the planned measurements of implant strain and denture-bearing area loading. The SL-model was generated using the patient's computer tomographic data and duplicated in a material of known elastic properties. The model was fitted with sensors to measure strains in the peri-implant bone and loading forces within the posterior mandibular bone, i.e. the denture-bearing area of the mandible. Special telescopic copings were constructed to measure implant strain in this model as well as in vivo. Using these copings under identical overdenture loading conditions, the strains measured at the implants in vivo and in vitro were the same and never exceeded a tolerance of two standard deviations or a mean difference of -8.5% of the in vitro value. This indicates that the model was reliable for the measurement of implant strain. Denture-bearing area loading within the alveolar ridge cannot be measured in vivo. Instead, a method of extrapolating in vivo denture-bearing area loading figures from implant strain readings was developed and tested (better than 90% accuracy). These in vivo extrapolated figures were then compared to in vitro readings under otherwise identical loading conditions. The result indicated that the SL-model is reliable for measurements of denture-bearing area loading with an error of 10 to 20%.

Overdenture attachment selection and the loading of implant and denture-bearing area. Part 2: A methodical study using five types of attachment

In general, an implant is loaded via axial and horizontal forces. Besides this, moment loading can also occur. The aim of this study was to investigate how different prosthetic connectors with overdentures develop force transfer to implant and bone as well as to the denture-bearing alveolar ridge. Five connectors were investigated on a stereolithographic model fabricated according to a real patient situation. The model was fitted with strain gauges on the "bone" distal and medial to the implants and with vertical force transducers in the alveolar "bone" under the denture-bearing area. The parallel-sided rigid telescopic connector developed the highest moment loading of the implant (P<0.001), which would suggest restraint in the use of this connector. The bar construction also showed somewhat high moments but these may have been at least partly exaggerated by the individual patient situation. Loading results through the non-rigid telescopic copings, single spherical attachments and magnet overdentures demonstrated a low level of implant moment loading which would in part result from horizontal forces caused by denture forward shift during force application. The denture-bearing area loading was different with all attachments (P<0.001) and was related to the rigidity of the connector and reached the highest values with the non-rigid telescopic coping. The clinical implications of the various findings are discussed.

Renal tolerability of four different once-daily dose regimen of netilmicin in critical care patients

A prospective, randomized trial was conducted in a medical intensive care unit to assess safety and tolerability of four different dose regimens of intravenous netilmicin given once daily in the treatment of febrile episodes in critically ill patients. Eighty patients with febrile episodes during their stay in the intensive care unit were included in the study. The patients were randomized into four groups: Group 1 received a single daily dose of netilmicin based upon weight, age and renal function according to a dosage nomogram [13] (mean dose 298 +/- 29 mg, median 300 mg, range 250-350 mg), group 2 received 150% of this standard dose (mean 418 +/- 45 mg, median 400 mg, range 350-500 mg), group 3 200% (mean 525 +/- 41 mg, median 500 mg, range 400-550 mg) and group 4 250% (mean 710 +/- 39 mg, median 650 mg, range 600-750 mg). Duration of treatment was six days. Positive cultures were obtained in 29 patients. Serum creatinine and creatinine clearance, as well as netilmicin trough levels and levels of alpha 1-microglobulin showed no significant difference between the groups before, during, and after therapy. Our results indicate that with once daily dosing even high doses of netilmicin are well tolerated in patients with a creatinine clearance of > 70 ml/min before therapy. Necessary precautions include monitoring of drug trough levels (< 1 mg/L) and maintenance of adequate volume status.

Levels of stem cell factor and interleukin-3 in serum in acute Plasmodium falciparum malaria

The purpose of the present study was to measure serum concentrations of stem cell factor (SCF) and interleukin-3 (IL-3) in patients with acute Plasmodium falciparum malaria. Serum samples from 15 patients were taken on day of admission and days 7, 14, 21, and 28. Anemia developed in 80% of patients. A transient increase in IL-3 could be observed at the beginning of the disease. It remains controversial whether the measured concentrations of IL-3 and SCF correlate with the grade of anemia. The possibly suppressed IL-3 and SCF production may contribute to the prolonged anemia in P. falciparum malaria, as has been shown for erythropoietin.

[Bone tensile strength and hydrostatic stress]

A model making use of an elastic-plastic material law and continuous damage mechanics has been developed to define the strength of trabecular bone. With the aid of this model, the differences in the behaviour of bone under tensile and compressive stresses can be simulated numerically. It is also possible to calculate the loss of strength of bone via a damage variable. The calculated results are in good agreement with stress-strain curves determined experimentally.

Enantioselective inhibition of TNF-alpha release by thalidomide and thalidomide-analogues

The question whether the immunomodulating activity of rac-thalidomide resides in either the (-)-(S)- or the (+)-(R)-enantiomer was addressed by synthesis and separation of pure enantiomers of thalidomide analogues which carry a methyl-group at the asymmetric carbon atom and are thus prevented from racemization. The effect of the pure enantiomers of the thalidomide-analogues and also of the enantiomers of thalidomide on release of TNF-alpha was tested in vitro by using stimulated peripheral mononuclear blood cells. Both enantiomers of thalidomide inhibited the release of TNF-alpha equally well at low concentrations (5 and 12.5 micrograms/ml) but at higher concentrations (25 and 50 micrograms 50 micrograms/ml) there was a weak but statistically significant selectivity towards the (-)-(S)-enantiomer. In the case of the configuration-stable thalidomide-analogues there was a very pronounced and statistically significant enantioselectivity towards the (S)-form even at lower concentrations (> or = 5 micrograms/ml). The (S)-enantiomers of the thalidomide-analogues differed in their inhibitory potency from (-)-(S)-thalidomide suggesting that the introduction of the methyl-group increases the TNF-alpha-inhibitory activity while the reduction of one of the carbonyl-functions in the glutarimide-moiety to a methylene-group decreases activity. The effect of these small molecular alterations on activity and the enantioselectivity towards the (S)-enantiomers may indicate that thalidomide and its analogues directly interact with one or several cellular target-proteins.

Recent advances in the immunopathogenesis of insulin-dependent diabetes mellitus

Insulin-dependent diabetes mellitus places a major burden on both affected individuals and society because of its high morbidity and mortality rates and financial costs. That the disease occurs in genetically susceptible individuals as a result of an immunologically mediated process thought to be triggered by environmental factors probably operating in early childhood is well established. Enhanced knowledge of the immunopathogenesis, genetics, and natural history of insulin-dependent diabetes mellitus in nonobese diabetic mice and humans has enabled investigators to better predict disease onset and design therapies aimed at its prevention. Major national and international multicenter trials are currently in progress, engendering cautious optimism that the disease may safely be prevented.

Islet cell antibodies predict insulin-dependent diabetes in United States school age children as powerfully as in unaffected relatives

Islet cell antibodies (ICA) in the sera of nondiabetic relatives of patients with insulin-dependent diabetes (IDD) are predictive of the disease, a finding that permits the design of intervention strategies to prevent it. However, 85% or more of patients with new onset IDD have no affected relative. We therefore screened 9,696 schoolchildren between the ages of 5 and 18 yr (mean age 10.7 yr) in Pasco County, Florida for ICA in three surveys during 1984/5, 1987/8, and 1990/1 and have followed them prospectively. Approximately 4,000 of these children have been followed for nearly 8 yr. ICA titers > or = 10 Juvenile Diabetes Foundation units on replicate tests were detected in 57 of the children (0.59%). 10 children have developed diabetes so far, and all had ICA detected beforehand. The likelihood of developing IDD among the ICA-positive children was compared with 2,959 age-matched nondiabetic first degree relatives of IDD probands who were screened for ICA by our laboratory during the same time period and also followed prospectively. Of 103 (3.5%) ICA-positive relatives, 31 have developed IDD. Life table analysis reveals no statistically significant differences in the probability of developing IDD between the ICA-positive schoolchildren and ICA-positive first degree relatives (P = 0.3). The estimated risk of developing IDD by 7 yr in the ICA-positive schoolchildren was 45% (95% confidence interval 15-74%) compared with 43% (confidence interval 22-63%) in the relatives. We conclude that ICA appear to be as predictive of IDD in low-risk schoolchildren as they are in high-risk relatives. These data suggest that it is feasible to predict IDD by screening a general population of schoolchildren for ICA and that those found to be positive could be considered, in addition to relatives, for intervention protocols to prevent the disease.

[Mechanics of damage and biomechanical tensile strength of the femur]

The properties of the femur are represented by the micromechanics of composites and the mechanics of damage. A consideration of the femur as a composite the Young's modul is dependent on the density. The biomechanical behavior of the femur can be simulated by a one-dimensional model of the mechanics of damage. It is shown that the maximal tolerable stress and the yield stress are not direct material properties. Material behavior is determined by a damage variable that is dependent on the current strain. The results of this investigation are in good agreement with experimental results.

[Mechanical aspects of the development of artificial heart valves]

The development of an antithrombogenic coating permits a hybrid design for artificial heart valves. A substrate material optimized for its application is coated to meet the electrochemical requirements of improved hemocompatibility. But future progress in artificial heart valves requires an improvement in design as well as of the material. The basis of both aspects is the determination of such fundamental mechanical properties as the elasticity and plasticity of the valve ring and the deformation and fraction behaviour of the occluder. Analytical and numerical calculations of various different models result in different requirements for the substrate of ring and occluder. A combination of high elastic temper and low resistance to flow requires a ring material with a Young's modulus of 40 GPa or more, and a 0.2% proof stress to (Young's modulus)2/3 ratio of 0.3 MPa1/3. The best occluder materials should have a Young's modulus of more than 50 GPa and a flexural strength of at least 800 MPa. On the basis of these criteria, a heart valve consisting of a TiA15Fe2,5 ring and occluders made partially stabilized zirconia is introduced.

Rheumatoid nodules of the spine: case report and review of the literature

We present the case of a patient who had rheumatoid nodules of the vertebrae, which had resulted in bony destruction of the spine at 3 levels. Although there have been only 3 previous reports of such findings with confirmation by histologic analysis, we believe the condition is more common than has been thought. From a review of the literature, we found that similar clinical and radiographic features, as well as descriptions of rheumatoid granulation tissue invading the disc spaces, have been described in several subjects.

Molecular genetics of insulin-dependent diabetes mellitus

Insulin-dependent diabetes mellitus is an autoimmune disease the development of which is influenced by genetic factors (Cahill & McDevitt, 1981). As concordance for IDD is less than 50% in identical twins, environmental factors are also required for the development of IDD. Although viral agents have been implicated in the past, the specific environmental components leading to IDD remain unknown. This paper reviews current research focused on the genetic factors that influence susceptibility to IDD.