Cardiac Safety of Kinase Inhibitors - Improving Understanding and Prediction of Liabilities in Drug Discovery Using Human Stem Cell-Derived Models

Many small molecule kinase inhibitors (SMKIs) used to fight cancer have been associated with cardiotoxicity in the clinic. Therefore, preventing their failure in clinical development is a priority for preclinical discovery. Our study focused on the integration and concurrent measurement of ATP, apoptosis dynamics and functional cardiac indexes in human stem cell-derived cardiomyocytes (hSC-CMs) to provide further insights into molecular determinants of compromised cardiac function. Ten out of the fourteen tested SMKIs resulted in a biologically relevant decrease in either beating rate or base impedance (cell number index), illustrating cardiotoxicity as one of the major safety liabilities of SMKIs, in particular of those involved in the PI3K–AKT pathway. Pearson's correlation analysis indicated a good correlation between the different read-outs of functional importance. Therefore, measurement of ATP concentrations and apoptosis in vitro could provide important insight into mechanisms of cardiotoxicity. Detailed investigation of the cellular signals facilitated multi-parameter evaluation allowing integrative assessment of cardiomyocyte behavior. The resulting correlation can be used as a tool to highlight changes in cardiac function and potentially to categorize drugs based on their mechanisms of action.

Using trend arrows in continuous glucose monitoring systems for insulin adjustment in clinical practice: Brazilian Diabetes Society Position Statement

This manuscript reports the Brazilian Diabetes Society Position Statement for insulin adjustments based on trend arrows observed in continuous glucose monitoring systems. The Brazilian Diabetes Society supports the utilization of trend arrows for insulin dose adjustments in patients with diabetes on basal-bolus insulin therapy, both with multiple daily insulin doses or insulin pumps without closed-loop features. For those on insulin pumps with predictive low-glucose suspend feature, we suggest that only upward trend arrows should be used for adjustments. In this paper, tables for insulin adjustment based on sensitivity factors are provided and strategies to optimize the use of trend arrows in clinical practice are discussed.

The "replication crisis" in the public eye: Germans' awareness and perceptions of the (ir)reproducibility of scientific research

Several meta-analytical attempts to reproduce results of empirical research have failed in recent years, prompting scholars and news media to diagnose a "replication crisis" and voice concerns about science losing public credibility. Others, in contrast, hoped replication efforts could improve public confidence in science. Yet nationally representative evidence backing these concerns or hopes is scarce. We provide such evidence, conducting a secondary analysis of the German "Science Barometer" ("Wissenschaftsbarometer") survey. We find that most Germans are not aware of the "replication crisis." In addition, most interpret replication efforts as indicative of scientific quality control and science's self-correcting nature. However, supporters of the populist right-wing party AfD tend to believe that the "crisis" shows one cannot trust science, perhaps using it as an argument to discredit science. But for the majority of Germans, hopes about reputational benefits of the "replication crisis" for science seem more justified than concerns about detrimental effects.

Elevated Thrombomodulin Plasma Levels as a Result of Endothelial Involvement in Plasmodium falciparum Malaria

We used thrombomodulin (TM) to assess the participation of the vascular endothelium in human Plasmodium falciparum (P. F.) malaria. Before therapy TM plasma levels were elevated in P. F. malaria and fell to normal values during therapy. Parasitemia, TNFα, elastase and TAT levels correlated directly with TM. Elevated TM levels can not be explained by increased synthesis, since incubating HUVEC with pretherapy serum of patients with P. F. malaria, but not reconvalescence serum, suppressed TM transcription. This was partially prevented by adding a TNFα neutralizing antibody to patient serum before incubation with HUVEC. However, TNFα does not release TM from cultured HUVEC in vitro. Coincubation of HUVEC with pretherapy serum together with neutrophils resulted in endothelial cell destruction, which could be partly prevented by a TNFα neutralizing antibody. Hence the increase of TM during P. F. malaria might reflect the concerted action of cytokines and neutrophils on HUVEC.

Antiparasitic Treatment of Patients with P. falciparum Malaria Reduces the Ability of Patient Serum to Induce Tissue Factor by Decreasing NF-κB Activation

Serum from patients with P. falciparum malaria at day 1 (pretherapy) induces tissue factor (TF) in cultured endothelial cells. TF induction depends on de novo transcription as shown in Nuclear Run On assays. Electrophoretic mobility shift assays demonstrated binding of AP-1 and NF- κB/Rel proteins to their recognition sites in the TF promotor. After therapy (day 28), stimulation of TF antigen by patient serum is reduced by 70%. When serum obtained before and after therapy was compared, a decrease of NF-κB activation was evident. Activation of NF-κB-like proteins was in part dependent on TNFα in patient serum, since a TNFα neutralizing antibody reduced induction of TF transcription and translation and induction of NF-κB-like proteins. Induction of TF activity was suppressed by pDTC, an inhibitor of NF-κB activation. When different promotor constructs of the TF gene were tested, induction was dependent upon the presence of the intact NF-κB-like binding site in the TF promotor. A mutant with deleted NF-κB, but intact AP-1 sites was not inducible. Mutation of the AP-1 sites did not prevent induction, but reduced inducibility by pretherapy serum. Therefore, NF-κB/Rel proteins are responsible for induction of TF transcription by pretherapy serum, but AP-1 is needed for highest inducibility. The effect of antiparasitic therapy on the induction of TF by serum from patients with complicated P. falciparum malaria is dependent on a therapy-mediated loss of activation of NF-κB-like proteins in post-treatment patient serum.

Einfluß prätherapeutischer Variablen auf die Wirkung einer standardisierten 131J-Therapie mit 150 Gray beim Morbus Basedow

Ziel: Bei 61 Patienten mit einem Morbus Basedow haben wir den Einfluß prätherapeutischer Variablen auf die Funktion und das Volumen der Schilddrüse ein Jahr nach einer 131J-Therapie mit 150 Gray untersucht. Methoden: FT3, FT4, und TSH wurden vor Therapie und eineinhalb, 3, 6 und 12 Monate nach Therapie gemessen. Das Schilddrüsenvolumen wurde vor Therapie und ein Jahr nach Therapie sonographisch und szin-tigraphisch bestimmt. Ergebnisse: Ein Jahr nach Therapie waren 30% der Patienten latent oder manifest hyperthyreot, 24% euthyreot, und 46% latent oder manifest hypothyreot. Lebensalter und Ausgangsvolumen der Schilddrüse waren die Hauptprädiktoren der posttherapeutischen Schilddrüsenfunktion. Der Anteil an persistierenden Hyperthyreosen war bei älteren Patienten mit einem Schilddrüsenvolumen größer 50 ml mit über 70% besonders hoch. Bei fast allen Patienten kam es zu einer deutlichen Verkleinerung der Schilddrüse. Ausgangsvolumen und Lebensalter waren auch hier die Hauptprädiktoren der posttherapeutischen Schilddrüsengröße. Bei allen Patienten jünger als 50 Jahre kam es sogar unabhängig von der Ausgangsgröße zu einer Normalisierung des Schilddrüsenvolumens. Schlußfolgerung: Eine Radiojodtherapie mit 150 Gray führt bei den meisten Patienten mit einem Morbus Basedow zu einer deutlichen Verkleinerung der Schilddrüse. Alter und initiales Volumen haben einen wesentlichen Einfluß auf die Funktion und Größe der Schilddrüse nach Therapie und sollten bei der Dosisfestlegung berücksichtigt werden.

GLI1+ progenitor cells in the adrenal capsule of the adult mouse give rise to heterotopic gonadal-like tissue

As certain strains of mice age, hyperplastic lesions resembling gonadal tissue accumulate beneath the adrenal capsule. Gonadectomy (GDX) accelerates this heterotopic differentiation, resulting in the formation of wedge-shaped adrenocortical neoplasms that produce sex steroids. Stem/progenitor cells that reside in the adrenal capsule and retain properties of the adrenogonadal primordium are thought to be the source of this heterotopic tissue. Here, we demonstrate that GLI1⁺ progenitors in the adrenal capsule give rise to gonadal-like cells that accumulate in the subcapsular region. A tamoxifen-inducible Cre driver (Gli1-creER^T2) and two reporters (R26R-lacZ, R26R-confetti) were used to track the fate of GLI1⁺ cells in the adrenal glands of B6D2F2 mice, a strain that develops both GDX-induced adrenocortical neoplasms and age-dependent subcapsular cell hyperplasia. In gonadectomized B6D2F2 mice GLI1⁺ progenitors contributed to long-lived adrenal capsule cells and to adrenocortical neoplasms that expressed Gata4 and Foxl2, two prototypical gonadal markers. Pdgfra, a gene expressed in adrenocortical stromal cells, was upregulated in the GDX-induced neoplasms. In aged non-gonadectomized B6D2F2 mice GLI1⁺ progenitors gave rise to patches of subcapsular cell hyperplasia. Treatment with GANT61, a small-molecule GLI antagonist, attenuated the upregulation of gonadal-like markers (Gata4, Amhr2, Foxl2) in response to GDX. These findings support the premise that GLI1⁺ progenitor cells in the adrenal capsule of the adult mouse give rise to heterotopic tissue.

A case of pharyngeal diphtheria in Germany, June 2015

BACKGROUND

In June 2015, a 45-year-old man suffering from acute necrotic tonsillitis and throat phlegmon was hospitalized in Nuremberg, Germany. After emergency surgery the patient was initially treated with antibiotics.

RESULTS

A throat swab grew a toxigenic Corynebacterium diphtheriae biovar mitis strain. The patient's vaccination status was not documented and the patient was tested serologically for anti-diphtheria antibodies showing no protective immunity. Extensive control investigations were performed by the local health department showing no likely source of his infection.

CONCLUSION

No secondary cases were found and the patient completely recovered.

[Structural changes in the lateral tibiofemoral compartment after high tibial osteotomy]

BACKGROUND

Valgus high tibial osteotomy (HTO) increases the pressure in the lateral tibiofemoral compartment.

OBJECTIVE

The purpose of this work is to provide an overview about current knowledge on the effect of HTO on the lateral tibiofemoral osteochondral unit and lateral meniscus.

MATERIALS AND METHODS

Studies in translational models on the effect of medial opening wedge HTO on the lateral tibiofemoral osteochondral unit and lateral meniscus are reviewed and placed in the clinical perspective. Emphasis is placed on specific correlations between topographical alterations of the cartilage, subchondral bone, and meniscus in the lateral tibiofemoral compartment.

DISCUSSION

Specific topographical relationships exist in the central region between the articular cartilage and subchondral bone plate thickness, and in the submeniscal periphery between the articular cartilage and lateral meniscus, emphasizing the important protective role of the lateral meniscus. Following standard correction, the pressure increase in the lateral compartment following valgus HTO does not induce significant structural changes in the lateral tibiofemoral compartment. A higher increase in pressure following valgus overcorrection induces adaptive changes in the lateral compartment, reflected by an increased specific bone surface (BS/BV) in the subarticular spongiosa compared with unloading by varisation. Valgus overcorrection also leads to a decrease in the number of cells in the red-red (peripheral) zone of the middle third of the lateral menisci, without structural changes.

RESULTS

In conjunction with the clinical data these results show that opening wedge HTO is a safe procedure for the lateral tibial osteochondral unit and the lateral meniscus.

Toying with fate: Redirecting the differentiation of adrenocortical progenitor cells into gonadal-like tissue

Cell fate decisions are integral to zonation and remodeling of the adrenal cortex. Animal models exhibiting ectopic differentiation of gonadal-like cells in the adrenal cortex can shed light on the molecular mechanisms regulating steroidogenic cell fate. In one such model, prepubertal gonadectomy (GDX) of mice triggers the formation of adrenocortical neoplasms that resemble luteinized ovarian stroma. Transcriptomic analysis and genome-wide DNA methylation mapping have identified genetic and epigenetic markers of GDX-induced adrenocortical neoplasia. Members of the GATA transcription factor family have emerged as key regulators of cell fate in this model. Expression of Gata4 is pivotal for the accumulation of gonadal-like cells in the adrenal glands of gonadectomized mice, whereas expression of Gata6 limits the spontaneous and GDX-induced differentiation of gonadal-like cells in the adrenal cortex. Additionally, Gata6 is essential for proper development of the adrenal X-zone, a layer analogous to the fetal zone of the human adrenal cortex. The relevance of these observations to developmental signaling pathways in the adrenal cortex, to other animal models of altered adrenocortical cell fate, and to human diseases is discussed.

Kaleidoscope model of diabetes care: time for a rethink?

National Audit Data highlight persistent sub-optimum control among increasing numbers of people living with diabetes, with severe consequences for the individual and the NHS. The aim of the present review was to introduce a new cohesive, holistic model of care, tailored to individual needs to support optimum diabetes outcomes. This model of diabetes is necessary in order to understand the driving forces behind behaviour and their impact on diabetes management. Feelings (an emotional state or reaction) and beliefs (an acceptance that something is true or real) are fundamental behavioural drivers and influence diabetes self-management choices. Individually, these explain some of the complexities of behaviour and, collectively, they impact on personal motivation (rationale/desire to act) to achieve a specific outcome. Inevitably, they independently affect diabetes self-management and the environment in which individuals live. A model of care that proposes the encompassing of environment, intrinsic thought and therapy regimens to provide tailored, personalized healthcare should support enhanced diabetes self-management and outcomes from diagnosis. The Kaleidoscope model of care could be deliverable in routine care, incorporating each of the influences on diabetes self-management, and should benefit both individuals with diabetes and healthcare professionals.

[Tuberculosis infection control - recommendations of the DZK]

The epidemiological situation of tuberculosis (TB) in Germany has improved considerably during the past few years. However, those in unprotected contact with infectious tuberculosis patients frequently and/or over longer periods of time and/or intensively continue to have a higher risk for TB infection. Rapid diagnosis, prompt initiation of effective treatment, and adequate infection control measures are of particular importance to prevent infection. The present recommendations depict the essentials of infection control as well as specific measures in the hospital (isolation, criteria for its duration and technical requirements, types of respiratory protection, disinfection measures, waste disposal). The specific requirements for outpatients (medical practice), at home, for ambulance services, and in congregate settings, including prisons, are also addressed. Compared with the previous recommendations the pattern of respiratory protection measures has been simplified. As a rule, hospital staff and those visiting infectious tuberculosis patients are advised to wear respiratory protection that satisfies the criteria of FFP2-masks (DIN EN 149), while patients should wear mouth-nose protectors (surgical masks) in the presence of others and outside the isolation room. A detailed depiction of criteria for isolation and its duration in smear positive and only culturally confirmed pulmonary tuberculosis has been added.

[Tuberculosis infection control--recommendations of the DZK]

The epidemiological situation of tuberculosis (TB) in Germany has improved considerably during the past few years. However, those in unprotected contact with infectious tuberculosis patients frequently and/or over longer periods of time and/or intensively continue to have a higher risk for TB infection. Rapid diagnosis, prompt initiation of effective treatment, and adequate infection control measures are of particular importance to prevent infection. The present recommendations depict the essentials of infection control as well as specific measures in the hospital (isolation, criteria for its duration and technical requirements, types of respiratory protection, disinfection measures, waste disposal). The specific requirements for outpatients (medical practice), at home, for ambulance services, and in congregate settings, including prisons, are also addressed. Compared with the previous recommendations the pattern of respiratory protection measures has been simplified. As a rule, hospital staff and those visiting infectious tuberculosis patients are advised to wear respiratory protection that satisfies the criteria of FFP2-masks (DIN EN 149), while patients should wear mouth-nose protectors (surgical masks) in the presence of others and outside the isolation room. A detailed depiction of criteria for isolation and its duration in smear positive and only culturally confirmed pulmonary tuberculosis has been added.

Increase of patients co-colonised or co-infected with methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium or extended-spectrum β-lactamase-producing Enterobacteriaceae

PURPOSE

To determine the incidence of patients co-colonised or co-infected with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium or extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in four German tertiary care hospitals.

METHODS

This study was conducted at four tertiary care hospitals (all with >1,000 beds) in different geographic regions in Germany (Berlin in the east, Luebeck in the north, Freiburg in the southwest and Nuernberg in the southeast). Routine surveillance data on MRSA, vancomycin-resistant enterococci (VRE) and ESBL-producing bacteria were analysed from 2007 to 2009. Co-colonisation or co-infection was defined as a patient having positive cultures for at least two of the following resistant pathogens: MRSA, VRE faecium or different species of ESBL-producing Enterobacteriaceae within one calendar year.

RESULTS

A total of 896,822 patients were analysed, of which 10,066 patients harboured MRSA, VRE faecium and/or ESBL-producing Enterobacteriaceae, and 542 patients co-harboured at least two of those resistant pathogens. In 2009, 7.6% of the MRSA patients, 13.7% of the VRE faecium patients and even 16.1% of the ESBL-producing Enterobacteriaceae patients were co-colonised or co-infected. The incidence of patients with co-infection or co-colonisation increased steadily from 5 (2007) to 7 per 10,000 patients (2009).

CONCLUSIONS

Patients harbouring ESBL-producing Enterobacteriaceae or VRE faecium had a higher risk of being co-colonised or co-infected compared to what was to be extrapolated from their overall incidence. This might be linked to their gastrointestinal reservoir and impracticality to decolonise the gut of resistant VRE and ESBL-producing Enterobacteriaceae.

Comprehensive analysis of hormone and genetic variation in 36 genes related to steroid hormone metabolism in pre- and postmenopausal women from the breast and prostate cancer cohort consortium (BPC3)

CONTEXT

Sex steroids play a central role in breast cancer development.

OBJECTIVE

This study aimed to relate polymorphic variants in 36 candidate genes in the sex steroid pathway to serum concentrations of sex steroid hormones and SHBG.

DESIGN

Data on 700 genetic polymorphisms were combined with existing hormone assays and data on breast cancer incidence, within the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Nurses' Health Study (NHS) cohorts; significant findings were reanalyzed in the Multiethnic Cohort (MEC).

SETTING AND PARTICIPANTS

We analyzed data from a pooled sample of 3852 pre- and postmenopausal Caucasian women from EPIC and NHS and 454 postmenopausal women from MEC.

MAIN OUTCOME MEASURES

Outcome measures were SHBG, testosterone, dehydroepiandrosterone (DHEAS), androstenedione, estrone (E1), and estradiol (E2) as well as breast cancer risk.

RESULTS

Globally significant associations were found among pre- and postmenopausal women combined between levels of SHBG and the SHBG gene and between DHEAS and the FSHR and AKR1C3 genes. Among postmenopausal women, serum E1 and E2 were significantly associated with the genes CYP19 and FSHR, and E1 was associated with ESR1. None of the variants related to serum hormone levels showed any significant association with breast cancer risk.

CONCLUSIONS

We confirmed associations between serum levels of SHBG and the SHBG gene and of E1 and E2 and the CYP19 and ESR1 genes. Novel associations were observed between FSHR and DHEAS, E1, and E2 and between AKR1C3 and DHEAS.

The putative AKH receptor of the tobacco hornworm, Manduca sexta, and its expression

Adipokinetic hormones are peptide hormones that mobilize lipids and/or carbohydrates for flight in adult insects and activate glycogen Phosphorylase in larvae during starvation and during molt. We previously examined the functional roles of adipokinetic hormone in Manduca sexta L. (Lepidoptera: Sphingidae). Here we report the cloning of the full-length cDNA encoding the putative adipokinetic hormone receptor from the fat body of M. sexta. The sequence analysis shows that the deduced amino acid sequence shares common motifs of G protein-coupled receptors, by having seven hydrophobic transmembrane segments. We examined the mRNA expression pattern of the adipokinetic hormone receptor by quantitative Real-Time PCR in fat body during development and in different tissues and found the strongest expression in fat body of larvae two days after molt to the fifth instar. We discuss these results in relation to some of our earlier results. We also compare the M. sexta adipokinetic hormone receptor with the known adipokinetic hormone receptors of other insects and with gonadotropin releasing hormone-like receptors of invertebrates.

In Asian-American Women, Westernization Influences Estrogen Metabolism, but Not Total Endogenous Estrogen Production

Background: Historically, breast cancer incidence rates were 4-7 times higher in the United States than in China and Japan. When Asian women migrate to the U.S., their risk rises over several generations and approaches that in U.S. Whites. Endogenous estrogen has been postulated to explain these international differences. Methods: In a population-based case-control study in Chinese, Japanese, and Filipino women living in San Francisco-Oakland, CA; Los Angeles, CA; or Oahu, HI, we documented a six-fold gradient in breast cancer risk with Westernization. Using 12-h, overnight urines from 263 premenopausal mid-luteal and 168 postmenopausal control subjects, we investigated associations of estrogens and estrogen metabolites (EM) with Westernization, particularly birthplace in the East or West. Fifteen EM were measured concurrently by liquid chromatography-tandem mass spectrometry with high accuracy, precision, and sensitivity. Log-transformed EM measures, adjusted for age and ethnicity, were compared by robust linear regression. Results: Total urinary EM (pmol/mg creatinine) was not associated with birthplace in premenopausal or postmenopausal women. When the three estrogen hydroxylation pathways were expressed as percent of total EM, the relative difference by birthplace, West compared to East, was 15% lower for 2-pathway EM (p=0.009), 7% lower for 4-pathway EM (p=0.37), and 10% higher for 16-pathway EM (p=0.008). Similar results were observed for individual EM in each pathway, premenopausal and postmenopausal women, and the three ethnicities. In both menopausal groups, 2-pathway EM concentration decreased steadily with increasing risk across six categories of Westernization. Conclusions: Our results do not indicate that total estrogen production explains the increased breast cancer risk in Western societies. However, estrogen metabolism patterns, especially reduced 2-hydroxylation, may contribute to the elevated risk; and underlying mechanisms merit further exploration.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3063.

Effect of glucocorticoid-, parathyroid- and thyroid hormones excess on human iliac crest bone matrix insulin-like growth factor (IGF)-I in patients with osteoporosis

Insulin-like growth factor-I (IGF-I) is a well documented bone-active growth factor. Clinical studies reported that circulating hormones may affect serum IGF-I levels, with potential consequences on bone remodeling. However, no data on bone matrix concentrations of IGF-I in subjects with endocrine dysfunction is available in humans. Bone mineral density and cancellous bone matrix IGF-I levels were assessed in iliac crest biopsies from 38 patients with low bone mass related to glucocorticoid- (n=10), parathyroid- (n=14) or thyroid (n=14) hormones excess. Results were compared to those of sex- and age-matched patients with primary osteoporosis. Bone matrix extraction was performed based on a guanidine-chlorhidric acid/ethylendiamine-tetraacetic acid method. Long-term glucocorticoid therapy (> or =24 months) led to significantly lower cancellous bone matrix IGF-I levels in comparison to age-matched controls (p=0.03). Although higher trabecular bone IGF-I levels were seen in hyperparathyroid subjects, the difference was not significant in comparison to controls (p=0.24). Likewise, no difference was noticed in cancellous bone matrix IGF-I concentrations between subjects with low bone mass and sub-clinical or overt thyrotoxicosis and euthyroid controls. Neither parathyroid hormone (PTH) nor thyroxin (T (4)) concentrations were associated with bone matrix IGF-I levels. To conclude, our study documented that in vivo long-term corticotherapy is associated with low trabecular human bone matrix IGF-I. In contrast, no influence of increased circulating parathyroid- or thyroid hormones levels on human iliac crest skeletal IGF-I concentrations was observed.

Cyclic AMP formation in rat bone and kidney cells is stimulated equally by parathyroid hormone-related protein (PTHrP) 1-34 and PTH 1-34

Parathyroid hormone-related protein (PTHrP) plays a major role in the pathogenesis of humoral hypercalcemia of malignancy. It interacts with the PTH receptor and has therefore a nearly identical effect on bone cells as PTH. However, PTHrP is thought to be less potent than PTH in stimulating adenylate cyclase in canine renal membranes, leading to the hypothesis of a differential efficiency in signal transduction by PTHrP with respect to bone vs kidney. In a homologous model with intact osteoblast-like cells (UMR 106) and primary kidney cells, both from the rat, we have tested N-terminal peptide fragments, based on the rat amino acid sequence 1-34, of PTH and PTHrP. Compared with PTHrP(1-34), rat PTH(1-34) had a similar relative potency in bone cells (85%) and in kidney cells (140%) in its ability to stimulate adenylate cyclase. Human PTH(1-34) was 5.6- to 6.5-fold less potent than rat PTH(1-34) in both cell types. In human osteoblast-like cells (SaOS-2), rat and human PTH were essentially equally potent compared to PTHrP(1-34) (identical sequence in rat and human) in stimulating cAMP accumulation. In conclusion, our study revealed the equipotency of rat PTH(1-34) and PTHrP(1-34) in stimulating intracellular cAMP formation in a homologous system of rat bone and kidney cells. There seemed to be no unique signal transduction mechanism of PTHrP to the adenylate cyclase in rat kidney cells compared with bone cells.

Clinical significance of antibodies against calcitonin

Calcitonin (CT) inhibits osteoclast-mediated bone resorption and is being used to treat Paget's disease of bone, hypercalcemia of malignancy and postmenopausal osteoporosis. The formation of antibodies against heterologuous calcitonins like salmon calcitonin (sCT) is common and occurs in 40-70% of the patients treated for more than 4 months. Not all of these patients, however, develop a secondary resistance to sCT, therefore the clinical significance of sCT antibodies is discussed controversially. In vivo and in vitro approaches demonstrate a neutralizing effect in 35 to 60% of the patient sera with antibodies against sCT. These neutralizing antibodies appear to explain most cases of clinically relevant secondary resistance to sCT treatment, which occurs in 25-45% of the patients after treatment periods of 6 months and longer. A positive treatment response to human CT after development of secondary resistance to sCT proves the diagnosis of antibody related resistance. Few cases develop secondary resistance in the absence of sCT binding antibodies, the mechanism of this phenomenon is unclear. Antibody related resistance is a significant problem in long term treatment with sCT. Especially in conditions like postmenopausal osteoporosis, where no readily accessable marker of treatment response is available, the development of sCT antibodies and their possible neutralizing effect has to be considered.

Bone mineral density and calcium regulating hormones in patients with inflammatory bowel disease (Crohn's disease and ulcerative colitis)

Inflammatory bowel disease (Crohn's disease and ulcerative colitis) is associated with decreased bone mineral density and increased risk of osteoporosis. However, the pathogenesis of this bone loss is not yet fully understood. In the present study we measured lumbar bone mineral density (by dual photon absorptiometry), serum levels of parathyroid hormone (PTH) and vitamin D metabolites, and serum markers of bone turnover (alkaline phosphatase and osteocalcin) in 15 patients with Crohn's disease and in 4 patients with ulcerative colitis. The median duration of the disease was 4 years and the median lifetime steroid dose was 10g of prednisone. We compared our results to a control group of 19 normal persons, who were matched for age and sex to the patients. We found that lumbar bone density was reduced by 11% in patients compared with control persons (Z-score -0.6 +/- 0.6 versus -0.1 +/- 0.8; p < 0.05). In patients, the serum levels of PTH, 25-hydroxyvitamin D3, and calcitriol (1,25(OH)2D3) were significantly reduced compared with control persons. Serum alkaline phosphatase activity (AP) was significantly higher in the patients and was inversely related to lumbar bone density. Osteocalcin values were not different between patients and control persons. There was also no difference in serum levels of calcium between the two groups, whereas phosphorus levels were higher in patients. We conclude that malabsorption of calcium was not a primary cause of bone loss in our patients, because we did not find secondary hyperparathyroidism. Accordingly, we did not find a severe vitamin D deficiency, since 25-hydroxyvitamin D3 levels were within the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)