NIBR-LTSi is a selective LATS kinase inhibitor activating YAP signaling and expanding tissue stem cells in vitro and in vivo

The YAP/Hippo pathway is an organ growth and size regulation rheostat safeguarding multiple tissue stem cell compartments. LATS kinases phosphorylate and thereby inactivate YAP, thus representing a potential direct drug target for promoting tissue regeneration. Here, we report the identification and characterization of the selective small-molecule LATS kinase inhibitor NIBR-LTSi. NIBR-LTSi activates YAP signaling, shows good oral bioavailability, and expands organoids derived from several mouse and human tissues. In tissue stem cells, NIBR-LTSi promotes proliferation, maintains stemness, and blocks differentiation in vitro and in vivo. NIBR-LTSi accelerates liver regeneration following extended hepatectomy in mice. However, increased proliferation and cell dedifferentiation in multiple organs prevent prolonged systemic LATS inhibition, thus limiting potential therapeutic benefit. Together, we report a selective LATS kinase inhibitor agonizing YAP signaling and promoting tissue regeneration in vitro and in vivo, enabling future research on the regenerative potential of the YAP/Hippo pathway.

Generalized onset seizures with focal evolution (GOFE) - a largely unknown ictal variation in genetic generalized epilepsies

PURPOSE

At onset of generalized seizures, focal electroclinical features are commonly seen, while generalized onset seizures with focal evolution (GOFE) are largely unknown bearing the risk of misclassification.

METHODS

In two German epilepsy-centers, patients with GOFE documented by video-EEG monitoring (VEM) between 2017 and 2022 were identified retrospectively. In addition to analysis of ictal electroclinical features, detailed epilepsy and family history, response to antiseizure medication (ASM), and findings from neuroimaging were considered.

RESULTS

We identified five patients with GOFE, three females, age 14 to 22 years. All patients developed genetic generalized epilepsy in childhood or adolescence, each presenting with two or three generalized seizure types. In each of the five patients, one GOFE was recorded by VEM. At onset, EEG seizure patterns were characterized by generalized spike-wave discharges at 2.5 to 3.5/sec for 9 to 16 s followed by focal evolution of the discharges. Interictally, all patients presented with generalized spike-wave discharges without focal abnormalities. Semiology at onset was behavioral arrest in two patients and generalized increase in tone in one, while two onsets were clinically inapparent. Semiological signs during focal evolution were variable, comprising head and body version, figure 4 sign, unilateral arm clonic activity, and staring with oral automatisms. In one case, focality involved both hemispheres successively.

CONCLUSION

Prominent focal semiological features in GOFE carry a high risk of misclassification as focal seizures and epilepsy and thus wrong choice of ASM. This calls for low-threshold VEM if any doubts of focal genesis of seizures exist.

Screening for mitochondrial function before use-routine liver assessment during hypothermic oxygenated perfusion impacts liver utilization

BACKGROUND

To report on a concept of liver assessment during ex situ hypothermic oxygenated perfusion (HOPE) and its significant impact on liver utilization.

METHODS

An analysis of prospectively collected data on donation after circulatory death (DCD) livers, treated by HOPE at our institution, during a 11-year period between January 2012 and December 2022.

FINDINGS

Four hundred and fifteen DCD Maastricht III livers were offered during the study period in Switzerland, resulting in 249 liver transplants. Of those, we performed 158 DCD III liver transplants at our institution, with 1-year patient survival and death censored graft survival (death with functioning graft) of 87 and 89%, respectively, thus comparable to benchmark graft survivals of ideal DBD and DCD liver transplants (89% and 86%). Correspondingly, graft loss for primary non-function or cholangiopathy was overall low, i.e., 7/158 (4.4%) and 11/158 (6.9%), despite more than 82% of DCD liver grafts ranked high (6-10 points) or futile risk (>10 points) according to the UK-DCD score. Consistently, death censored graft survival was not different between low-, high-risk or futile DCD III livers. The key behind these achievements was the careful development and implementation of a routine perfusate assessment of mitochondrial biomarkers for injury and function, i.e., release of flavin mononucleotide from complex I, perfusate NADH, and mitochondrial CO2 production during HOPE, allowing a more objective interpretation of liver quality on a subcellular level, compared to donor derived data.

INTERPRETATION

HOPE after cold storage is a highly suitable and easy to perform perfusion approach, which allows reliable liver graft assessment, enabling surgeons to make a fact based decision on whether or not to implant the organ. HOPE-treatment should be combined with viability assessment particularly when used for high-risk organs, including DCD livers or organs with relevant steatosis.

FUNDING

This study was supported by the Swiss National Foundation (SNF) grant 320030_189055/1 to PD.

Novel Benchmark Values for Open Major Anatomic Liver Resection in Non-cirrhotic Patients: A Multicentric Study of 44 International Expert Centers

OBJECTIVE

This study aims at establishing benchmark values for best achievable outcomes following open major anatomic hepatectomy for liver tumors of all dignities.

BACKGROUND

Outcomes after open major hepatectomies vary widely lacking reference values for comparisons among centers, indications, types of resections, and minimally invasive procedures.

METHODS

A standard benchmark methodology was used covering consecutive patients, who underwent open major anatomic hepatectomy from 44 high-volume liver centers from 5 continents over a 5-year period (2016-2020). Benchmark cases were low-risk non-cirrhotic patients without significant comorbidities treated in high-volume centers (≥30 major liver resections/year). Benchmark values were set at the 75th percentile of median values of all centers. Minimum follow-up period was 1 year in each patient.

RESULTS

Of 8044 patients, 2908 (36%) qualified as benchmark (low-risk) cases. Benchmark cutoffs for all indications include R0 resection ≥78%; liver failure (grade B/C) ≤10%; bile leak (grade B/C) ≤18%; complications ≥grade 3 and CCI ® ≤46% and ≤9 at 3 months, respectively. Benchmark values differed significantly between malignant and benign conditions so that reference values must be adjusted accordingly. Extended right hepatectomy (H1, 4-8 or H4-8) disclosed a higher cutoff for liver failure, while extended left (H1-5,8 or H2-5,8) were associated with higher cutoffs for bile leaks, but had superior oncologic outcomes, when compared to formal left hepatectomy (H1-4 or H2-4). The minimal follow-up for a conclusive outcome evaluation following open anatomic major resection must be 3 months.

CONCLUSION

These new benchmark cutoffs for open major hepatectomy provide a powerful tool to convincingly evaluate other approaches including parenchymal-sparing procedures, laparoscopic/robotic approaches, and alternative treatments, such as ablation therapy, irradiation, or novel chemotherapy regimens.

Defatting of Human Livers During Long-Term e x situ Normothermic Perfusion: Novel Strategy to Rescue Discarded Organs for Transplantation

OBJECTIVE

To develop a protocol for the defatting of steatotic liver grafts during long-term ex situ normothermic machine perfusion.

BACKGROUND

Despite the alarming increase in donor organ shortage, the highly prevalent fatty liver grafts are often discarded due to the risk of primary nonfunction. Effective strategies preventing such outcomes are currently lacking. An exciting new avenue is the introduction of ex situ normothermic machine perfusion (NMP), enabling a liver to remain fully functional for up to 2 weeks and providing a unique window of opportunity for defatting before transplantation.

METHODS

Over a 5-year period, 23 discarded liver grafts and 28 partial livers from our resection program were tested during ex situ normothermic machine perfusion. The steatosis degree was determined on serial biopsies by expert pathologists, and triglyceride contents were measured simultaneously.

RESULTS

Of 51 liver grafts, 20 were steatotic, with up to 85% macrovesicular steatosis, and were perfused for up to 12 days. Ten livers displayed marked (5 of which almost complete) loss of fat, while the other 10 did not respond to long-term perfusion. Successful defatting was related to prolonged perfusion, automated glucose control, circadian nutrition, and L-carnitine/fenofibrate supplementation. Pseudopeliotic steatosis and the associated activation of Kupffer/stellate cells were unexpected processes that might contribute to defatting. Synthetic and metabolic functions remained preserved for most grafts until perfusion ended.

CONCLUSION

Ex situ long-term perfusion effectively reduces steatosis while preserving organ viability and may in the future allow transplantation of primarily unusable high-risk grafts, significantly increasing the number of organs available for transplantation.

Normalization of lipid oxidation defects arising from hypoxia early posthepatectomy prevents liver failure in mouse

Surgical liver failure (SLF) develops when a marginal amount of hepatic mass is left after surgery, such as following excessive resection. SLF is the commonest cause of death due to liver surgery; however, its etiology remains obscure. Using mouse models of standard hepatectomy (sHx) (68%, resulting in full regeneration) or extended hepatectomy (eHx) (86%/91%, causing SLF), we explored the causes of early SLF related to portal hyperafflux. Assessing the levels of HIF2A with or without oxygenating agent inositol trispyrophosphate (ITPP) indicated hypoxia early after eHx. Subsequently, lipid oxidation (PPARA/PGC1α) was downregulated and associated with persisting steatosis. Mild oxidation with low-dose ITPP reduced the levels of HIF2A, restored downstream PPARA/PGC1α expression along with lipid oxidation activities (LOAs), and normalized steatosis and other metabolic or regenerative SLF deficiencies. Promotion of LOA with L-carnitine likewise normalized the SLF phenotype, and both ITPP and L-carnitine markedly raised survival in lethal SLF. In patients who underwent hepatectomy, pronounced increases in serum carnitine levels (reflecting LOA) were associated with better recovery. Lipid oxidation thus provides a link between the hyperafflux of O₂-poor portal blood, the metabolic/regenerative deficits, and the increased mortality typifying SLF. Stimulation of lipid oxidation-the prime regenerative energy source-particularly through L-carnitine may offer a safe and feasible way to reduce SLF risks in the clinic.

Robotic Distal Pancreatectomy, a Novel Standard of Care? Benchmark Values for Surgical Outcomes from 16 International Expert Centers

BACKGROUND AND OBJECTIVE

Robotic distal pancreatectomy (DP) is an emerging attractive approach, but its role compared to laparoscopic or open surgery remains unclear. Benchmark values are novel and objective tools for such comparisons. The aim of this study was to identify benchmark cutoffs for many outcome parameters for DP with or without splenectomy beyond the learning curve.

METHODS

This study analyzed outcomes from international expert centers from patients undergoing robotic DP for malignant or benign lesions. After excluding the first 10 cases in each center to reduce the effect of the learning curve, consecutive patients were included from the start of robotic DP up to June 2020. Benchmark patients had no significant comorbidities. Benchmark cutoff values were derived from the 75th or the 25th percentile of the median values of all benchmark centers. Benchmark values were compared to a laparoscopic control group from four high-volume centers and published open DP landmark series.

RESULTS

Sixteen centers contributed 755 cases, whereof 345 benchmark patients (46%) were included the analysis. Benchmark cut-offs included: operation time ≤300min, conversion rate ≤3%, clinically relevant POPF ≤32%, 3 months major complication rate ≤26.7% and lymph node retrieval ≥9. The CCI® at 3 months was ≤8.7 without deterioration thereafter. Compared to robotic DP, laparoscopy had significantly higher conversion rates (5x) and overall complications, while open DP was associated with more blood loss and longer hospital stay.

CONCLUSION

This first benchmark study demonstrates that robotic DP provides superior postoperative outcomes compared to laparoscopic and open DP. Robotic DP may be expected to become the approach of choice in minimally invasive DP.

Real-World Experience Treating Pediatric Epilepsy Patients With Cenobamate

Introduction

In one third of all patients with epilepsy, seizure freedom is not achieved through anti-seizure medication (ASM). These patients have an increased risk of earlier death, poorer cognitive development, and reduced quality of life. Cenobamate (CNB) has recently been approved as a promising novel ASM drug for the treatment of adults with focal-onset epilepsy. However, there is little experience for its application in pediatric patients.

Methods

In a multicenter study we evaluated retrospectively the outcome of 16 pediatric patients treated “off label” with CNB.

Results

In 16 patients with a mean age of 15.38 years, CNB was started at an age of 15.05 years due to DRE. Prior to initiation of therapy, an average of 10.56 (range 3–20) ASM were prescribed. At initiation, patients were taking 2.63 (range 1–4) ASM. CNB was increased by 0.47 ± 0.27mg/kg/d every 2 weeks with a mean maximum dosage of 3.1 mg/kg/d (range 0.89–7) and total daily dose of 182.81 mg (range 50–400 mg). Seizure freedom was achieved in 31.3% and a significant seizure reduction of >50% in 37.5%. Adverse events occurred in 10 patients with fatigue/somnolence as the most common. CNB is taken with high adherence in all but three patients with a median follow-up of 168.5 days

Conclusion

Cenobamate is an effective ASM for pediatric patients suffering from drug-resistant epilepsy. In addition to excellent seizure reduction or freedom, it is well-tolerated. Cenobamate should be considered as a novel treatment for DRE in pediatric patients.

Robotic distal pancreatectomy, a novel standard of care? First benchmark values for surgical outcomes from 14 international expert centers

Objective

Robotic distal pancreatectomy (DP) is emerging as the preferred treatment for body and tail tumors of the pancreas. To enable conclusive comparisons with the standard open or laparoscopic approaches and robotic surgery among centers, novel benchmark outcome values are urgently needed. Therefore, the aim of this study was to identify benchmark values from expert centers beyond the learning curve.

Methods

This multicenter study analyzed outcomes from consecutive patients undergoing robotic DP for resectable malignant or benign lesions from 14 international expert centers. After the learning curve, defined as the first 10 cases of robotic DP, all consecutive patients were included from the start of the program up to June 2020 with a minimum follow-up of 1 year. Benchmark patients were those without significant comorbidities including obesity (BMI >35 kg/m2) cardiac disease, chronic pulmonary disease.

Benchmark cutoff values were derived from the 75th or the 25th percentile of the median values of all benchmark centers.

Results

After reaching the learning curve, 289 (47%) of a total of 614 consecutive patients qualified as benchmark cases. The proportion of benchmark patients varied between 24%-64% per center. Benchmark cut-offs showed a low 6 month- postoperative mortality (<0.6%), but high overall morbidity (<58.3%). Benchmark cutoffs for operative time (<300 min), conversion rate (<3%), clinically relevant pancreatic fistulas (<26.9%), CCI at 90-days (<14.8), hospital stay (<7 days) and readmission rate (<22.9%). Benchmark cut-offs for complications remained unchanged after 3 months follow-up. For ductal adenocarcinoma benchmark cutoffs for number of lymph nodes were > 19 with an R0 resection rate of > 85%, and an overall survival of >86% and >52% after 1- and 5-years, respectively. Centers with a low cohort of benchmark patients (more difficult cases) had less clinically relevant pancreatic fistula (9% vs. 23%) and less overall complications (32% vs. 48%).

Conclusion

This benchmark analysis sets novel reference values for robotic DP, indicating favorable outcomes as compared to laparoscopic and open DP. These references values may serve for quality control of surgery in centers embarking in robotic DP, and include the procedure in the standard of care.

Long-term outcomes of transplant kidneys donated after circulatory death

BACKGROUND

Donation after circulatory determination of death (DCD) represents up to 40% of used kidney grafts. While studies have shown similar outcome compared to donation after brain death (DBD) on the short- and mid-term, no data on long-term outcomes exist.

METHODS

We retrospectively analyzed patients transplanted at our institution between January 1985 and March 2000. All DCD recipients were matched one-to-one with patients transplanted with DBD grafts during this period according to sex, age, and year of transplantation, and followed-up until December 2020. During this period, 1133 kidney transplantations were performed, 122 of which with a DCD graft.

RESULTS

Median graft survival after 35-years follow-up was 23 years (277 months; CI 182 -372) in DBD, and 24.5 years (289 months; CI 245 - 333) in DCD (P = 0.65; HR = 0.91). Delayed graft function occurred in 47 patients in the DCD group compared to 23 in the DBD group (P < 0.001), albeit without significant long-term outcome difference in graft or patient survival. We could not show any difference in graft function, in terms of creatinine levels (133 µmol/l vs. 119 µmol/l), proteinuria (370 mg/24h vs. 240 mg/24h), nor GFR slope (-0.6 ml/min/year vs. -0.3 ml/min/year) between the two groups for grafts surviving more than 20 years.

CONCLUSIONS

This is the first study to show similar graft survival and function in DCD kidneys compared to DBD after 35 years follow-up. DCD grafts are a valuable resource and can be utilized in the same way as DBD grafts.

CD26 as a target against fibrous formation in chronic airway rejection lesions

AIMS

Chronic lung allograft dysfunction (CLAD) after lung transplantation (Tx) is the clinical result of chronic airway rejection lesions (CARL), histomorphologically described as either obliterative remodeling of small airways or alveolar fibroelastosis, or as a combination of both. We here investigated the CD26-inhibitory effect on CD26-expressing CARL.

MAIN METHODS

CARL were induced by BALB/c → C57BL/6 mouse Tx under mild immunosuppression. CARL-related pro-fibrotic mediators were determined by RT-qPCR and western blotting (WB), EMT and ERK markers by WB. CD26 co-expression by immunofluorescence. CD26 was inhibited by Vildagliptin, gene depleted by CD26^-/- mice. Primary lung fibroblasts were employed for ex vivo analyses. Samples from lung transplant patients with CLAD were analyzed by immunohistochemistry.

KEY FINDINGS

CARL revealed a significantly higher expression of profibrotic proteins vs. normal lungs (p < 0.05). CD26 and EMT co-expressed in CARL with significantly higher Vimentin, Slug, Hif-1α, α-SMA expression vs. normal lungs (p < 0.05). Vildagliptin decreased the expression of α-SMA and N-cadherin in wild type (WT) lung fibroblasts (p < 0.05). Primary lung fibroblasts from WT and CD26^-/- mice treated with TGF-β1, IFN-γ, and FGF showed a reduction of EMT protein expression, proliferation, and reduced activation of ERK in CD26^-/- mice vs. WT mice. CD26-positive cells were found in patient samples with CLAD in areas of loose fibrosis, but not in areas of dense fibrosis.

SIGNIFICANCE

CD26 is expressed in CARL-developing lung transplants and CD26-inhibition downregulates fibrosis-forming mediators and fibroblast proliferation. CD26 thus qualifies as a target to attenuate the development of CARL mainly via modulation of ERK and the EMT pathway.

Site of Recurrence and Survival After Surgery for Colorectal Peritoneal Metastasis

BACKGROUND

Multimodal treatment, including systemic treatment and surgery, improved the prognosis of peritoneal metastasis (PM). Despite all efforts, recurrence rates remain high, and little data are available about clinical behavior or molecular patterns of PM in comparison to hematogenous metastasis. Here, we aimed to analyze recurrence patterns after multimodal treatment for PM from colorectal cancer.

METHODS

Patients with colorectal PM undergoing multimodal treatment including systemic chemotherapy and cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) between 2005 and 2017 at 4 centers were analyzed retrospectively.

RESULTS

A total of 505 patients undergoing CRS/HIPEC were analyzed. Of the patients, 82.1% received preoperative chemotherapy. Median peritoneal cancer index was 6 (interquartile range = 3-11). Median disease-free and overall survival was 12 (95% confidence interval [CI] = 11 to 14) months and 51 (95% CI = 43 to 62) months, respectively. Disease recurred in 361 (71.5%) patients, presenting as isolated peritoneal recurrence in 24.6%, isolated hematogenous recurrence in 28.3%, and mixed recurrence in 13.9% of patients. Recurrence to the peritoneum was associated with an impaired time from recurrence to death of 21 (95% CI = 18 to 31) months for isolated peritoneal and 22 (95% CI = 16 to 30) months for mixed recurrence, compared with 43 (95% CI = 31 to >121) months for hematogenous recurrence (hazard ratio [HR] = 1.79, 95% CI = 1.27 to 2.53; P = .001; and HR = 2.44, 95% CI = 1.61 to 3.79; P < .001). On multiple logistic regression analysis, RAS mutational status (odds ratio [OR] = 2.42, 95% CI = 1.11 to 5.47; P = .03) and positive nodal stage of the primary (OR = 3.88, 95% CI = 1.40 to 11.86; P = .01) were identified as predictive factors for peritoneal recurrence.

CONCLUSIONS

This study highlights the heterogeneity of peritoneal metastasis in patients with colorectal cancer. Recurrent peritoneal metastasis after radical treatment represents a more aggressive subset of metastatic colorectal cancer.

Sleep-Disordered Breathing in REM Sleep Behavior Disorder with or without Parkinson's Disease

REM sleep behavior disorder (RBD) might render patients with Parkinson's disease prone to sleep-disordered breathing. This retrospective polysomonographic study assessed the prevalence of sleep-disordered breathing in 108 consecutive patients with either both Parkinson's disease and RBD (n = 37), Parkinson's disease without RBD (n = 21), or isolated RBD (n = 50). Across all patients, 25% had at least moderate sleep-related breathing disorder, without significant differences between groups. Following multivariable analysis, RBD influenced sleep-related breathing parameters modestly but not significantly, whereas body mass index had a prominent impact. Further studies with larger patient cohorts are needed, and confounders like body mass index must adequately be controlled for.

How to achieve the desired outcomes of advance care planning in nursing homes: a theory of change

BACKGROUND

Advance care planning (ACP) has been identified as particularly relevant for nursing home residents, but it remains unclear how or under what circumstances ACP works and can best be implemented in such settings. We aimed to develop a theory that outlines the hypothetical causal pathway of ACP in nursing homes, i.e. what changes are expected, by means of which processes and under what circumstances.

METHODS

The Theory of Change approach is a participatory method of programme design and evaluation whose underlying intention is to improve understanding of how and why a programme works. It results in a Theory of Change map that visually represents how, why and under what circumstances ACP is expected to work in nursing home settings in Belgium. Using this approach, we integrated the results of two workshops with stakeholders (n = 27) with the results of a contextual analysis and a systematic literature review.

RESULTS

We identified two long-term outcomes that ACP can achieve: to improve the correspondence between residents’ wishes and the care/treatment they receive and to make sure residents and their family feel involved in planning their future care and are confident their care will be according to their wishes. Besides willingness on the part of nursing home management to implement ACP and act accordingly, other necessary preconditions are identified and put in chronological order. These preconditions serve as precursors to, or requirements for, accomplishing successful ACP. Nine original key intervention components with specific rationales are identified at several levels (resident/family, staff or nursing home) to target the preconditions: selection of a trainer, ensuring engagement by management, training ACP reference persons, in-service education for healthcare staff, information for staff, general practitioners, residents and their family, ACP conversations and documentation, regular reflection sessions, multidisciplinary meetings, and formal monitoring.

ONCLUSIONS

The Theory of Change map presented here illustrates a theory of how ACP is expected to work in order to achieve its desired long-term outcomes while highlighting organisational factors that potentially facilitate the implementation and sustainability of ACP. We provide the first comprehensive rationale of how ACP is expected to work in nursing homes, something that has been called for repeatedly.

A syndrome of the dentate nucleus mimicking psychogenic ataxia

To date, cerebellar involvement in control of non-motor functions like cognition and emotion is increasingly well established. Current models suggest that motor and non-motor networks connecting the cerebellum with cortical areas operate independently in closed and segregated loops. Here, we report a 59-year-old female patient with a small cerebellar lesion that shows that cognitive activation can significantly influence cerebellar motor control. Surprisingly, this led to a clinical picture mimicking a psychogenic disorder. Similar to non-human primates, this case suggests that the human dentate nucleus consists of distinct cognitive and motor domains with additional somatotopical arrangement of the latter. Extending current models of cerebro-cerebellar interaction, this case further illustrates that there can be significant functional cross-talk between motor and cognitive cerebellar networks.

The extracellular matrix protein ITIH5 is a novel prognostic marker in invasive node-negative breast cancer and its aberrant expression is caused by promoter hypermethylation

Inter-alpha-trypsin inhibitors (ITIs) are protease inhibitors stabilizing the extracellular matrix. ITIs consist of one light (bikunin) and two heavy chains (ITIHs). We have recently characterized ITIH5, a novel member of the ITIH gene family, and showed that its messenger RNA is lost in a high proportion of breast tumours. In the present study, an ITIH5-specific polyclonal antibody was generated, validated with western blot and used for immunohistochemical analysis on a tissue microarray; ITIH5 was strongly expressed in epithelial cells of normal breast (n=11/15), while it was lost or strongly reduced in 42% (92/217) of invasive breast cancers. ITIH5 expression in invasive carcinomas was associated with positive expression of oestrogen receptor (P=0.008) and histological grade (P=0.024). Correlation of ITIH5 expression with clinical outcome revealed that patients with primary tumours retaining abundant ITIH5 expression had longer recurrence-free survival (RFS; P=0.037) and overall survival (OS; P=0.044), compared to those with reduced expression (mean RFS: 102 vs 78 months; mean OS: 120 vs 105 months). Methylation-specific PCR analysis frequently showed strong methylation of the ITIH5 promoter in primary breast tumours (41%, n=109) and breast cancer cell lines (n=6). Methylation was significantly associated with mRNA loss (P<0.001; n=39), and ITIH5 expression was induced after treatment of tumour cell lines with the demethylating agent 5-aza-2'-deoxycytidine. Moreover, ITIH5 promoter methylation was significantly associated with reduced OS (P=0.008). The cellular function of ITIH5 was evaluated by forced expression of a full-length ITIH5 complementary DNA in the breast cancer cell line MDA-MB-231, which does not endogenously express ITIH5. ITIH5-expressing clones showed a 40% reduced proliferation rate compared to mock-transfected cells. Overall, these data show that promoter methylation-mediated loss of ITIH5 expression is associated with unfavourable outcome in breast cancer patients, and thus ITIH5 could be used as a prognostic marker, although this marker is not multivariate independent due to its close association with ER expression. Our data indicate that ITIH5 is a candidate class II tumour suppressor gene and could be involved in tumour progression, invasion and metastasis, as its absence is associated with increased proliferation rates and a prognostic value indicating poor clinical outcome.

Antibacterial substances of low molecular weight isolated from the blowfly, Lucilia sericata

Low molecular weight compounds were isolated by high-performance liquid chromatography from the maggot or haemolymph extracts of Lucilia sericata (Meigen) (Diptera: Calliphoridae). Using gas chromatography-mass spectrometry analysis, three compounds were obtained: p-hydroxybenzoic acid (molecular weight 138 Da), p-hydroxyphenylacetic acid (molecular weight 152 Da) and octahydro-dipyrrolo[1,2-a;1',2'-d] pyrazine-5,10-dione (molecular weight 194 Da), also known as the cyclic dimer of proline (or proline diketopiperazine or cyclo[Pro,Pro]). All three molecules revealed antibacterial activity when tested against Micrococcus luteus and/or Pseudomonas aeruginosa, and the effect was even more pronounced when these molecules were tested in combination and caused lysis of these bacteria.

Supercontinuum generation system for optical coherence tomography based on tapered photonic crystal fibre

We report smooth and broad continuum generation using a compact femtosecond Ti:Sapphire laser as a pump source and a tapered photonic crystal fibre as a nonlinear element. Spectral output is optimized for use in optical coherence tomography, providing a maximum longitudinal resolution of 1.5 microm in free space at 809 nm centre wavelength without use of additional spectral filtering.

Drill cutting accumulations in the Northern and Central North Sea: a review of environmental interactions and chemical fate

The exploration and production of North Sea oil and gas reserves has resulted in the accumulation of large quantities of drill cuttings on the seabed surrounding drill sites. This complex mixture of man-made and natural substances contains higher concentrations of certain metals (Ba, Cr, Cu, Ni, Pb, and Zn) and hydrocarbons than are observed in background sediments. With decommissioning of older platforms underway, an evaluation of the environmental interactions and chemical fate of the drill cuttings accumulations is required. This review concentrates on contaminants within drill cutting accumulations in the Northern and Central North Sea (56 degrees N-62 degrees N). Present literature reviewed reveals that hydrocarbons within the cuttings piles remain relatively unchanged with time. A considerable proportion of the associated contaminants are likely to remain within the cuttings pile unless they are disturbed which will then increase exchanges of porewater and solids back to the seabed surface resulting in pathways of exposure for organisms.

Primary breast cancer therapy in six regions of Germany

Studies from six regions of Germany (Aachen (W1), Dresden (E1), Jena (E2), Marburg (W2), Munich (W3), and Stuttgart (C1)) have been compared to verify and assess the quality of healthcare using breast cancer as an example. All of the data collection was carried out in comprehensive cancer centres and is population-based, with the exception of C1. Classic prognostic factors and the initial treatment of 8661 women with breast cancer, diagnosed between 1996 and 1998, were examined. Primary therapy, breast conserving therapy (BCT), and the use of subsequent local radiation and/or systemic therapy (chemotherapy or hormonal therapy) were analysed. BCT was performed on 39.3-57.7% of patients. By pT-category, the proportion of BCT in the six regions were as follows: for pTis between 37.8 and 64.3%, for pT1 between 51.7 and 71.5%, for pT2 between 25.9 and 51.1%, for pT3 between 0 and 13.1% and for pT4 between 0 and 15.2%. Multivariate analyses, adjusted for age and biological factors, showed a significant influence of the treating hospital on the mastectomy rate. The use of radiotherapy after BCT (80%) was quite homogeneous in the six regions. The application of radiotherapy after mastectomy, however, varied between 10.4 and 32.2%. In all regions, for premenopausal patients, the use of adjuvant systemic therapy almost reflected the St. Gallen-Consensus recommendations. In contrast, post-menopausal women with positive lymph nodes were not always treated according to these standards. In all regions, age had an influence on the administration of treatment: elderly breast cancer patients received less BCT, less radiotherapy and less adjuvant therapy than recommended in the St. Gallen-Consensus. Feedback of the results was made available to each hospital, providing a comparative summary of patient care that could be used by the participating hospitals for self-assessment and quality-control.

High reactivity of alkyl sulfides towards epoxides under conditions of collagen fixation--a convenient approach to 2-amino-4-butyrolactones

Epoxy crosslinking agents have been investigated for use in the fabrication of bioprosthetic devices, such as heterograft heart valve prostheses. It has been generally assumed that epoxy crosslinking takes place via amino-epoxy reactions. The present study investigated the hypothesis that the reactions of methionine residues with epoxides also can occur in biomaterial crosslinking. A series of model reactions were studied in which a mono-epoxide was combined with individual alkyl sulfides. In the present studies epoxides rapidly alkylate aliphatic sulfides, including methionine derivatives, in buffered aqueous solutions at room temperature and pH close to neutral, forming sulfonium compounds, which are stable at pH 5-7 at temperatures up to 50 degrees C, except for cases in which methionine derivatives with non-protected carboxy groups are used. The rate of reaction remains practically unchanged within the range of pH from 5 to 12, whereas in strongly alkaline media the reverse reaction occurs. This discovery can provide a better understanding of processes occurring in the fixation of bioprosthetic tissues with polyepoxides. It can also develop into a site-specific method to label methionine residues in proteins. The carboxy group-containing sulfonium betaines derived from N-protected methionines undergo cyclization in unexpectedly mild conditions, which can be used as an efficient method for preparation of N-protected 2-amino-4-butyrolactones with sensitive protective groups.

Different usage of the glycosaminoglycan attachment sites of biglycan

Biglycan is a member of the small leucine-rich proteoglycan family. Its core protein comprises two chondroitin/dermatan sulfate attachment sites on serine 42 and serine 47, respectively, which are the fifth and tenth amino acid residues, respectively, after removal of the prepro peptide. Because the regulation of glycosaminoglycan chain assembly is not fully understood and because of the in vivo existence of monoglycanated biglycan, mutant core proteins were stably expressed in human 293 and Chinese hamster ovary cells in which i) either one or both serine residues were converted into alanine or threonine residues, ii) the number of acidic amino acids N-terminal of the respective serine residues was altered, and iii) a hexapeptide was inserted between the mutated site 1 and the unaltered site 2. Labeling experiments with [(35)S]sulfate and [(35)S]methionine indicated that serine 42 was almost fully used as the glycosaminoglycan attachment site regardless of whether site 2 was available or not for chain assembly. In contrast, substitution of site 2 was greatly influenced by the presence or absence of serine 42, although additional mutations demonstrated a direct influence of the amino acid sequence between the two sites. When site 2 was not substituted with a glycosaminoglycan chain, there was also no assembly of the linkage region. These results indicate that xylosyltransferase is the rate-limiting enzyme in glycosaminoglycan chain assembly and implicate a cooperative effect on the xylosyl transfer to site 2 by xylosylation of site 1, which probably becomes manifest before the removal of the propeptide. It is shown additionally that biglycan expressed in 293 cells may still contain the propeptide sequence and may carry heparan sulfate chains as well as sulfated N-linked oligosaccharides.

[Solitary fibrous thoracic wall tumor. Progression with percutaneous radiotherapy]

HISTORY AND CLINICAL FINDINGS

A 81-year-old patient free of pain was referred to the university hospital for further evaluation and therapy of tumour masses in the right thorax. Clinical examination revealed dullness to percussion and reduced breathing in the right lower lung.

INVESTIGATIONS

Computed tomography showed an enlarged solid tumour mass attached to the thoracic cavity and pleural effusion on the right side. Quantification of pulmonary perfusion presented significant defects in the right upper and middle lobe.

DIAGNOSIS, TREATMENT AND COURSE

The pulmonary masses were biopsied under CT-guidance. Biopsy and immunohistochemical findings proved a malignant solitary fibrous tumour of the chest wall, a mesenchymal tumour of its own entity. Because of pain in the right arm and because of missing other reliable therapeutic options a palliative irradiation was performed. The tumour did increase in size due to radiotherapy and a severe right ventricular heart failure occurred. The patient died 5 months after diagnosis has been made. Autopsy revealed a transition of tumour cells to sarcomatic growth.

CONCLUSION

In our case we conclude an accelerated progression of the solitary fibrous chest wall tumour in the course of irradiation. Whether the development of sarcomatic growth occurred as a result of radiotherapy remains speculative.

A peptide prodrug approach for improving bisphosphonate oral absorption

This work was aimed at improving the absorption of bisphosphonates by targeting carrier systems in the intestine and the intestinal peptide carrier system (hPEPT1), in particular. (14)C-Labeled pamidronate and alendronate as well as radiolabeled and "cold" peptidyl-bisphosphonates, Pro-[(3)H]Phe-[(14)C]pamidronate, and Pro-[(3)H]Phe-[(14)C]alendronate were synthesized. In situ single-pass perfusion studies revealed competitive inhibition of transport by Pro-Phe, suggesting peptide carrier-mediated transport. Prodrug transport in the Caco-2 cell line was significantly better than that of the parent drugs, and the prodrugs exhibited high affinity to the intestinal tissue. Oral administration of the dipeptidyl prodrugs resulted in a 3-fold increase in drug absorption following oral administration in rats, and the bioavailability of Pro-Phe-alendronate was 3.3 (F(TIBIA)) and 1.9 (F(URINE)) times higher than that of the parent drug. The results indicate that the oral absorption of bisphosphonates can be improved by peptidyl prodrugs via the hPEPT1; however, other transporters may also be involved.

The effect of topical delivery of novel bisacylphosphonates in reducing alveolar bone loss in the rat model

BACKGROUND

Periodontal surgery stimulates osteoclast activity, leading to varying amounts of alveolar crest loss. We have established that topical application of 20 mg/ml of alendronate placed at the surgical mucoperiosteal site produced a striking reduction of alveolar bone loss in the rat model. The aim of this investigation was to examine the antiresorptive efficacy of 3 novel bisacylphosphonates topically delivered at the surgical site, in comparison to alendronate and etidronate which are in clinical use.

METHODS

Mucoperiosteal flap (MF) surgery was performed on the buccal and lingual aspects next to molars on both sides of the rat mandible. A gelatin sponge soaked in the bisphosphonate solution prepared by dissolving 20 mg of the bisphosphonate (alendronate, etidronate, VS-5, VS-6, ISA-13, SuBP) in 1 ml of saline was applied to exposed bone on the right side of the mandible (experimental, MF + BPs ) and the left side was treated with saline only (control, MF + S). Sections were evaluated for bone loss using microradiography pattern and amount.

RESULTS

The 3 novel bisacylphosphonates, VS-5 VS-6, and ISA-13 were more effective than etidronate, and less effective than alendronate. The most effective among this group was ISA-13 followed by VS-5 and VS-6.

CONCLUSION

We conclude that ISA-13-like alendronate is effective in reducing alveolar bone loss when delivered at surgical sites. Since ISA-13 is well absorbed through mucose tissues, we suggest that ISA-13 efficacy on reducing bone loss should be tested by its application on the mucosal tissue.

Synthesis and preclinical pharmacology of 2-(2-aminopyrimidinio) ethylidene-1,1-bisphosphonic acid betaine (ISA-13-1)-a novel bisphosphonate

PURPOSE

To validate our hypothesis that a bisphosphonate (BP) having a nitrogen-containing heterocyclic ring on the side chain, and with no hydroxyl on the geminal carbon would possess increased activity, and better oral bioavailability due to enhanced solubility of its calcium complexes/salts and weaker Ca chelating properties.

METHODS

A novel BP, 2-(2-aminopyrimidinio)ethylidene-1, 1-bisphosphonic acid betaine (ISA-13-1) was synthesized. The physicochemical properties and permeability were studied in vitro. The effects on macrophages, bone resorption (young growing rat model), and tumor-induced osteolysis (Walker carcinosarcoma) were studied in comparison to clinically used BPs.

RESULTS

The solubility of the Ca salt of ISA-13-1 was higher, and the log beta(Ca:BP) stability constant and the affinity to hydroxyapatite were lower than those of alendronate and pamidronate. ISA-13-1 exhibited effects similar to those of alendronate on bone volume, on bone osteolysis, and on macrophages, following delivery by liposomes. ISA-13-1 was shown to have 1.5-1.7 times better oral absorption than the other BPs with no deleterious effects on the tight junctions of intestinal tissue.

CONCLUSIONS

The similar potency to clinically used BPs, the increased oral absorption as well as the lack of effect on tissue tight junction of ISA-13-1 warrant its further consideration as a potential drug for bone diseases.

Transplacental effects of bisphosphonates on fetal skeletal ossification and mineralization in rats

Bisphosphonates are clinically used mainly to reduce bone resorption. We studied the transplacental effects of two bisphosphonates on the fetal skeleton in rats. Pregnant rats were treated during days 11-20 of pregnancy with daily subcutaneous injections of 0.1 mg/kg of alendronate or a newly synthesized bisphosphonate, VS-b6. This period of pregnancy was chosen because the active development of bones from mesenchyme through cartilaginous models occurs during that time. Histological examination of midlongitudinal sections of the 21-day-old fetuses showed an increase in the amount of diaphyseal bone trabeculae with slight shortening of the diaphysis in the experimental fetuses, in comparison to controls. Computerized histomorphometric studies similarly showed an increase in the amount of diaphyseal bone trabeculae with a concomitant decrease in bone marrow volume, but no change in cartilage volume. In addition, chemical analysis of the fetal bones showed an increase in calcium content in the treated fetuses. 14C-alendronate was shown to pass through the rat placenta and accumulate in the fetuses, most probably in their bones. This is presumed because bisphosphonates are known to accumulate in bone, being stored there for long periods of time. It is important, in light of our results, to give careful consideration to the treatment of women with bisphosphonates at childbearing age, whenever this is needed.

Disposition of alendronate following local delivery in a rat jaw

BACKGROUND

Recently, we have shown that local delivery of alendronate reduced significantly bone resorption activated by surgical separation of periosteum from bone. These results advocate the use of local application of alendronate in bone surgeries to prevent regional bone resorption at the surgery site. Here we investigated the efficacy of absorbtion of alendronate by the bone from a gelatin sponge soaked with radiolabeled alendronate applied topically at the surgical site.

METHODS

Following elevation of the mucoperiosteal flap next to premolars and molars of the rat mandible, a gelatin sponge soaked with 10 microl of radiolabled alendronate (1 microCi/mg) was applied to exposed bone on one side. The local absorbtion of alendronate and its disposition in the contralateral side of the mandible as well as in the tibia bone were analyzed.

RESULTS

The results show that 10% of total alendronate content of the gelatin sponge was absorbed in the bone locally (in the surgical site), while 0.2% was disposed in the tibia. Of interest is the fact that the surgical wound in the contralateral side increased the disposition of alendronate up to 2%. This finding is most likely the result of extravasation and diffusion of alendronate due to surgical wounding.

CONCLUSION

This study strongly supports our notion that local delivery of alendronate and its affinity to bone may become a very important treatment modality to prevent resorption of bone during dental and orthopedic procedures.

Bisphosphonates and tetracycline: experimental models for their evaluation in calcium-related disorders

PURPOSE

This work was aimed at synthesizing novel bisphosphonates (BPs) and examining them in comparison to clinically used BPs such as pamidronate and alendronate, and to tetracycline, in order to evaluate their potential as anticalcification and antiresorption agents. The correlation between the various models was examined in order to establish facile experimental models for pre-screening of potential compounds.

METHODS

Nitrogen-containing heterocyclic, novel BPs such as 2-(3-methylimidazolio) ethylidene-1,1-bisphosphonic acid betaine (VS-5b), 2-(2-dimethylamino-4-pyrazinio)ethylidene-1,1-bisphosphonic acid betaine (VS-6b), and 2-(2-alpha-pyridylethylthio) ethylidene-1,1-bisphosphonic acid (ISA-225), were synthesized and evaluated in comparison to clinically used BPs, in various experimental models of resorption and calcification.

RESULTS

The physicochemical properties of the novel compounds are slightly different than the BPs in clinical use: the pKa values are lower, the affinity for hydroxyapatite is lower and the solubilities of the calcium salts are higher. The anticalcification potencies of the novel compounds were high and ranked as follows: alendronate = pamidronate > VS-6b = VS-5b = ISA-225 > tetracycline. The in vivo antiresorption activity of VS-5b and VS-6b in comparison to that of the clinically employed, pamidronate, was shown to be similar and higher, respectively.

CONCLUSIONS

The anticalcification activity of the novel compounds as well as that of tetracycline was lower than that of alendronate. The antiresorption activity of VS-6b was similar to that of pamidronate. A good correlation between the different models was found, enabling the facile screening of novel compounds. The activities of tetracycline and EDTA highlight the distinct behavior of BPs as "crystal poison." In addition, tetracycline was found to be a potent anticalcification agent in the ectopic calcification model.

Structurally different bisphosphonates exert opposing effects on alkaline phosphatase and mineralization in marrow osteoprogenitors

Bisphosphonates (BPs) are inhibitors of bone resorption and soft tissue calcification. The biological effects of the BPs in calcium-related disorders are attributed mainly to their incorporation in bone, enabling direct interaction with osteoclasts and/or osteoblasts through a variety of biochemical pathways. Structural differences account for the considerable differences in the pharmacological activity of BPs. We compared the effects of two structurally different compounds, alendronate and 2-(3'-dimethylaminopyrazinio)ethylidene-1,1-bisphosphonic acid betaine (VS-6), in an osteoprogenitor differentiation system. The BPs were examined in a bone marrow stromal-cell culture system, which normally results in osteoprogenitor differentiation. The drugs were present in the cultures from days 2 to 11 of osteogenic stimulation, a period estimated as being comparable to the end of proliferation and the matrix-maturation stages. We found that the two different BPs have opposing effects on specific alkaline phosphatase (ALP) activity, on stromal-cell proliferation, and on cell-mediated mineralization. These BPs differentially interact with cell-associated phosphohydrolysis, particularly at a concentration of 10(-2) of ALP Km, in which alendronate inhibits whereas VS-6 did not inhibit phosphatase activity. VS-6 treatment resulted in similar and significantly increased mineralization at 10 and 1 microM drug concentrations, respectively. In contrast, mineralization was similar to control, and significantly decreased at 10 and 1 microM drug concentrations, respectively, under alendronate treatment.

In vitro and in vivo effects of tetrakisphosphonates on bone resorption, tumor osteolysis, ectopic calcification, and macrophages

The biological effects of bisphosphonates in calcium-related disorders are attributed to the incorporation of the bisphosphonates in bone, enabling direct interaction with osteoclasts and/or osteoblasts. The high accumulation of bisphosphonates in bone, due to their high affinity to hydroxyapatite (HAP), is essential for mediating in vitro and in vivo activity. In this study we examined the activity of tetrakisphosphonates, molecules containing two P-C-P type bisphosphonate moieties connected by a carbon chain. The novel compounds were examined in a battery of in vitro and in vivo models including HAP formation and dissolution, ectopic calcification, bone resorption, tumor osteolysis, and of macrophage-like cells (anti- or pro-inflammatory properties). The inhibition of ectopic calcification was ranked as follows: geminal bisphosphonates > bisacylphosphonates > tetrakisphosphonates. Pamidronate, but not the tetrakisphosphonates, was an effective antiosteolytic agent. Neither DNTP (tetrasodium 1,9-dihydroxynonane 1,1,9,9-tetrakisphosphonate) nor the bisacylphosphonate, PiBP (pimeloylbisphosphonate) seem to possess strong macrophage suppressive or inductive effects and can be considered to be relatively inactive in terms of anti- or pro-inflammatory action. A significant anticalcification effect was caused by various phosphonates, such as the tetrakisphosphonates, but DNTP, a tetrakisphosphonate, was found toxic as it impeded somatic growth and bone development.

In vitro inhibition of membrane-mediated calcification by novel phosphonates

The effects of a series of novel phosphonates on the kinetics of mineral development in an ionophore-primed 7:2:1 phosphatidylcholine (PC): dicetylphosphate (DCP): cholesterol (Chol) liposomal model system are reported. When present at 2.5 micromol/liter or 25 micromol/liter concentrations in the solution surrounding the liposomes, the investigated phosphonates did not significantly delay the initial formation of hydroxyapatite-like calcium phosphate salts (HAP) within the liposomes or the penetration of HAP crystals through the enclosing membranes. However, the phosphonates variably retarded the subsequent growth and proliferation of the HAP crystals once they became directly exposed to the phosphonate-containing solution. The effectiveness of phosphonates in inhibiting extraliposomal precipitation strongly depended on their structure. The inhibitory action on active surface growth sites of released intraliposomal crystals was found to be the most effective if the phosphonate molecule contained two phosphonic groups linked to the same C atom. At a phosphonate concentration of 25 micromol/liter, the following general order of effectiveness was established: geminal bisphosphonate >/= geminal tetrakisphosphonate > bisacylphosphonates > monoacylphosphonate > bisalkylphosphonate. Within the bisacylphosphonate family, the highest inhibitory action was observed when four or five -CH2- groups separated the ketophosphonic groups.

Anticalcification and antiresorption effects of bisacylphosphonates

Some geminal bisphosphonates are used clinically in a number of important bone and calcium-related diseases. This work reports the anticalcification and antiresorption effects of a series of bisacylphosphonates, nongeminal compounds with varying chain lengths having oxo groups in alpha positions relative to the phosphonic functions. We compared the activity of the novel compounds to clinically used geminal bisphosphonates, and to a bisphosphonate devoid of the oxo groups. The interaction of the compounds with calcium was studied by various in vitro and in vivo models. We found that keto groups in alpha positions to the phosphonic functions render activity. The bisacylphosphonates with a shorter chain [(CH2)n, = 4, 6] were found significantly to inhibit hydroxyapatite formation and dissolution in vitro, the calcification of bioprosthetic tissue implanted subdermally in rats, and bone resorption in the intact young animal model. The various in vitro results were found to be in good correlation with the in vivo results. Structure-activity relationship studies indicate that both bisacylphosphonates and geminal bisphosphonates are active only when at least three ionizable groups are present in the molecule. The role of the keto groups is related to their contribution to chelating calcium and/or to their electron-withdrawing influence on acidity.

Synthesis of some acylphosphonate thiosemicarbazones and evaluation of their antiviral activity

Reaction of dimethyl acylphosphonates (1) with thiosemicarbazide afforded the corresponding dimethyl acylphosphonate thiosemicarbazones (4). Lithium methyl acylphosphonate thiosemicarbazones (5) could be prepared either by monodealkylating compounds 4 by lithium bromide or by reacting lithium methyl acylphosphonates with thiosemicarbazide. Dihydrogen acylphosphonate thiosemicarbazones (6) could be obtained by reacting acylphosphonic acids (3) with thiosemicarbazide. The alternative approach to 6 by di-dealkylating compounds 4 using bromotrimethylsilane was limited by the solubility properties of esters 4. Compounds of types 5 and 6 did not show antiviral activity against herpes simplex type 1 and 2, or toward vaccinia virus.

In vitro and in vivo anticalcification effects of novel bishydroxyiminophosphonates

Some geminal bisphosphonates are used clinically for a number of important bone- and/or calcium-related diseases; however, side effects and lack of selectivity impede their wide use. This work reports the synthesis and evaluation of bishydroxyiminophosphonates (e.g., adipoyl- and suberoylbisphosphonate dioximes). These compounds significantly inhibited hydroxyapatite formation and dissolution in vitro and the calcification of bioprosthetic tissue implanted subdermally in rats. The compounds reported in this paper are less active than the structurally related bisacylphosphonates. The results of this work indicate that the introduction of oxime groups adjacent to the phosphonic function in long-chain bisphosphonates confers calcium interaction capabilities and that complete ionizability of a bisphosphonate may enhance its biological activity.

Bisacylphosphonates inhibit hydroxyapatite formation and dissolution in vitro and dystrophic calcification in vivo

Some geminal bisphosphonates are used clinically for a number of important bone/calcium related diseases; however, side effects and lack of selectivity impede their wide use. This work reports the synthesis and evaluation of bisacylphosphonates (e.g., adipoyl- and suberoylbisphosphonate). These compounds were found to inhibit significantly hydroxyapatite formation and dissolution in vitro and the calcification of bioprosthetic tissue implanted subdermally in rats. These are the first instances of nongeminal bisphosphonates [P-(C)n-P, n greater than or equal to 2] that have been reported to be active in calcium-related disorders. The reported bisacylphosphonates possess apparent lower toxicity, and their calcium complexes/salts have improved solubility properties. Therefore, they are of potential importance for clinical applications.

Distance geometry of alpha-substituted 2,2-diphenylpropionate antimuscarinics

Quantitative structure-activity relationships between pharmacological activities and physical properties of a series of 2,2-diphenylpropionate compounds were used to define the topography of the antagonist binding site of muscarinic receptors. XICAMM, a computer molecular modeling program, was used to calculate geometrical and topological values of the compounds. The compounds were tested for their antimuscarinic activities by: (a) inhibition of [N-methyl-3H]scopolamine binding to the muscarinic receptors of N4TG1 neuroblastoma cells, (b) inhibition of carbachol-induced alpha-amylase release from rat pancreas acini, and (c) blocking of acetylcholine-induced contraction of guinea pig ileum. To evaluate as clearly as possible only the effect of the bond distance on the potency of the synthesized antimuscarinics, the compounds contained as many constant features as possible. Neither the hydrophobic nor the ester moieties of the compounds were changed, and the rings containing the protonated nitrogen were saturated and restricted. The antimuscarinic activities obtained from the three assays were significantly correlated with each other, with the exception of two compounds, 9 and 13. The latter two compounds demonstrated specificity for the m3 muscarinic receptor subtype expressed in the pancreas. Furthermore, it was demonstrated that the antimuscarinic activities were significantly related to the bond distances between the carbonyl oxygen (constant electronegative locus) and the protonated nitrogen (center of cationic charge) of the 2,2-diphenylpropionate compounds. Parabolic relationships between the pharmacological activities and bond distances were empirically established. The shortest calculated bond distance of these compounds was approximately 4.4 A, whereas the longest was about 5.9 A. The maximum antimuscarinic potency was observed with a calculated bond distance of about 5.2 A in all three assays.