Integration of quantitative methods and mathematical approaches for the modeling of cancer cell proliferation dynamics

Physiological processes rely on the control of cell proliferation, and the dysregulation of these processes underlies various pathological conditions, including cancer. Mathematical modeling can provide new insights into the complex regulation of cell proliferation dynamics. In this review, we first examine quantitative experimental approaches for measuring cell proliferation dynamics in vitro and compare the various types of data that can be obtained in these settings. We then explore the toolbox of common mathematical modeling frameworks that can describe cell behavior, dynamics, and interactions of proliferation. We discuss how these wet-laboratory studies may be integrated with different mathematical modeling approaches to aid the interpretation of the results and to enable the prediction of cell behaviors, specifically in the context of cancer.

Generation of a zinc and rhodium containing metallomacrocycle by rearrangement of a six-coordinate precursor complex

Two pentadentate N3,P2 ligands coordinate zinc(ii) by their N3 pocket. Four free phosphine donors allow the coordination of four AuCl moieties leading to a pentanuclear ZnAu4 complex. In contrast, the attempt to use the phosphines for chelating coordination of two Rh(CO)Cl units results in a well-organized rearrangement that ends up with the formation of a metallomacrocycle in high yields.

Endovascular Cooling Catheter for Selective Brain Hypothermia: An Animal Feasibility Study of Cooling Performance

BACKGROUND AND PURPOSE

Therapeutic hypothermia represents a promising neuroprotective treatment in acute ischemic stroke. Selective cerebral hypothermia applied early, prior to and during endovascular mechanical recanalization therapy, may be beneficial in the critical phase of reperfusion. We aimed to assess the feasibility of a new intracarotid cooling catheter in an animal model.

MATERIALS AND METHODS

Nine adult sheep were included. Temperature probes were introduced into the frontal and temporal brain cortices bilaterally. The cooling catheter system was introduced into a common carotid artery. Selective blood cooling was applied for 180 minutes. Systemic and local brain temperatures were measured during cooling and rewarming. Common carotid artery diameters and flow were measured angiographically and by Doppler sonography.

RESULTS

The common carotid artery diameter was between 6.7 and 7.3 mm. Common carotid artery blood flow velocities increased moderately during cooling and after catheter removal. Maximum cerebral cooling in the ipsilateral temporal cortex was -4.7°C (95% CI, -5.1 to -4.0°C). Ipsilateral brain temperatures dropped significantly faster and became lower compared with the contralateral cortex with maximum temperature difference of -1.3°C (95% CI, -1.5 to -1.0°C; P < .0001) and compared with systemic temperature (-1.4°C; 95% CI, -1.7 to -1.0°C; P < .0001).

CONCLUSIONS

Sheep proved a feasible animal model for the intracarotid cooling catheter. Fast induction of selective mild hypothermia was achieved within the cooled cerebral hemisphere, with stable temperature gradients in the contralateral brain and systemic blood. Further studies are required to demonstrate any therapeutic benefit of selective cerebral cooling in a stroke model.

Combined Selective Cerebral Hypothermia and Mechanical Artery Recanalization in Acute Ischemic Stroke: In Vitro Study of Cooling Performance

BACKGROUND AND PURPOSE

Therapeutic hypothermia represents a promising neuroprotective treatment for patients with ischemic stroke. Selective, intracarotid blood cooling may initiate rapid and early brain hypothermia, reduce systemic effects, and allow combined endovascular mechanical thrombectomy. For this approach, a balloon cooling catheter system was designed and studied in vitro to optimize its cooling performance.

MATERIALS AND METHODS

Computational fluid dynamics of blood cooling was performed within the common carotid artery lumen by using 3 different catheter designs (1-, 2-, and 4-balloon array). On the basis of these results, a first catheter prototype was manufactured, and its heat-exchange performance was tested in an artificial in vitro circulation simulating the common carotid artery lumen at different flow rates (inflow temperature of 37°C).

RESULTS

In the computational fluid dynamics model, the catheter with the 4-balloon array achieved the highest cooling rate of -1.6°C, which may be attributed to disruption of the thermal boundary layers. In the in vitro study, cooling of the blood substitute at flow rates of 400 mL/min (normal common carotid artery flow) and 250 mL/min (reduced common carotid artery flow due to distal MCA occlusion) achieved a temperature drop inside the blood substitute along the cooling balloons of -1.6°C and -2.2°C, respectively.

CONCLUSIONS

The feasibility of intracarotid blood cooling using a new catheter system was demonstrated in vitro. A serial 4-balloon array led to an optimized cooling capacity approaching optimum target temperatures of mild therapeutic hypothermia. To determine the therapeutic efficacy of combined selective therapeutic hypothermia and mechanical thrombectomy, further in vivo studies by using a model of temporary ischemia with large-vessel occlusion and recanalization are required.

Internal Field Distribution in Organic Light Emitting Diodes with Double Layer Structure

Double layer organic light emitting devices (OLED) are constructed by evaporating tris(8 -hydroxy) quinoline aluminum (Alq3) on a spin cast thin film of a methyl substituted ladder type poly -para -phenylene (m -LPPP). A thick layer of Mg:Ag is used as the cathode material. These organic materials are very suitable for application in OLEDs both, as transporting materials as well as active layers. Alq3 predominantly transports electrons while m - LPPP is a conjugated polymer having higher hole mobilities. Due to these transport properties the formation and radiative recombination of the excitons in ITO/m -LPPP/Alq3/Mg:Ag devices occur close to the m -LPPP/Alq3 interface. We compare the device performance of OLEDs with varying Alq3 layer thickness (0, 50, 150, 300, 500Å) and constant m -LPPP layer thickness (900Å). A difference in the device parameters and performance as a function of the Alq3 layer thickness is observed. We analyze these results with respect to the internal electric field distribution of the double layer devices derived from electroabsorption measurements.

The Dielectric Response Of 8-Hydroxyquinoline Aluminum used in Multilayer Organic Devices

We present optical measurements of 8-hydroxyquinoline aluminum (Alq3) a metal-chelate complex which is an important material used for multilayer light emitting diodes. Thin films of Alq3 produced by vacuum deposition were investigated by transmission and reflectance spectroscopy, and the dielectric coefficients in the near IR to UV-Vis energy range were calculated. Kramers-Kronig analysis was used to determine the real and imaginary dielectric spectral dependence of the thin films. Values obtained by internal field distribution measurements in organic double layer LED's are compared to those determined from optical data. A near-IR value of epsilon (real component) close to 3 was obtained from optical measurements.

Protein multiplex sandwich immunoassay: A reliable and objective method for complete molecular characterization of breast cancer from core needle biopsies

20025

Background: Within the last years, protein microarrays have been developed to quantify a large number of parameters present in a given sample simultaneously. Such miniaturised and parallelised sandwich immunoassays are of general interest for all proteomic and diagnostic approaches in which several parameters have to be determined from small samples. We describe the development of a bead-based flow cytometry that represents a convenient approach for rapid multiplex detection of functional target molecules from breast cancer biopsies. Methods: Briefly, sonographically guided core needle biopsies (CNB) were performed from 120 breast cancer masses from different patients. All biopsies were carried out with an automated core biopsy device fitted with 14-gauge (22 mm excursion) needles. Tumor samples were frozen on at −70 Celsius and pulverized. Proteins were extracted, allowing the simultaneous quantification of more than hundred proteins by a bead-based multiplex sandwich immunoassay. Results: The total amount of extracted protein from tumor tissues (mean weight of 20 mg) ranged from 300 to 1000 μg. We demonstrate appropriate sensitivity, reproducibility, and robustness for this protein microarray technology to characterize clinical samples and generate reliable data sets. A set of multiplexed sandwich immunoassays based on Luminex beads were developed that identify marker proteins indicative of prognosis or response to therapeutic options. Up to almost hundred parameters were identified and quantified simultaneously of which estrogen, progesterone and HER2 status in the multiplex assay was highly significant correlated to results obtained by immunohistochemistry (IHC) (p < 0.01). Conclusions: Our results demonstrate that this new bead-based protein microarray technology rapidly and reliably characterizes tissue samples to generate data sets of molecular marker. Therefore, this technology may once replace traditional IHC in determining marker proteins indicative of prognosis or response to therapeutic options.

No significant financial relationships to disclose.

Influence of median sternotomy on the psychosomatic outcome in coronary artery single-vessel bypass grafting

OBJECTIVES

New less invasive surgical techniques for the treatment of coronary artery single-vessel disease have been developed by either avoiding median sternotomy or cardiopulmonary bypass or both, however, until now no prospective randomized trial has been carried out to compare these techniques to the conventional approach with special respect to the psychosomatical effects.

METHODS

In a prospective randomized trial four different surgical techniques were compared. Group 1: conventional technique (median sternotomy, cardiopulmonary bypass) in ten patients (eight male, two female, age 59.6 +/- 11.0 years); Group 2: off-pump coronary artery bypass with median sternotomy in nine patients (six male, three female, age 65.7 +/- 11.1 years); Group 3: lateral minithoracotomy and cardiopulmonary bypass in eight patients (five male, three female, age 62.3 +/- 9.9 years). Group 4: off-pump procedure and lateral minithoracotomy in nine patients (eight male, one female, age 63.8 +/- 11.3 years). All patients due to coronary artery single-vessel disease. The tests used for psychosomatic situation were post-traumatic stress disorders scale, pain behavior rating scale, pain visual analog scale, and 6' walking-distance. For detection of false results due to surgical technical failures 3-month follow-up was undertaken including echocardiography and coronary angiogram.

RESULTS

There were no deaths or major complications. Operative time was longer in lateral minithoracotomy procedures, but intensive care unit stay and hospitalization were equal in all groups. Pain visual analog scale and pain behavior rating scale showed a peak on post-operative day 4 in median sternotomy procedures. Post-traumatic stress disorder scale revealed higher values on post-operative day 4 and equalizing with lateral minithoracotomy procedures 1 month post-operatively. Six-minutes walking distance on post-operative day 4 was longer in the group with lateral minithoracotomy. Three-month follow-up revealed patency of all grafts.

CONCLUSIONS

Even if surgery is successful in all procedures, operative time is longer in lateral minithoracotomy procedures without compromising intensive care unit stay and hospital stay. More pain with multiple post-traumatic stress disorders is related to median sternotomy, and post-operative convalescence is superior for lateral minithoracotomy procedures.

[Minimal invasive surgical treatment of coronary multi-vessel disease]

To reduce surgical trauma and median sternotomy related complications in cardiac surgery, a new minimally invasive surgical technique has been developed for the treatment of coronary artery multivessel disease using a small left lateral chest incision in the 3rd intercostal space. This technique enables direct LIMA harvesting and performance of bypass surgery upon all coronary vessels with cardiopulmonary bypass and cardioplegic arrest. So far, 123 patients have been treated with this procedure and survived with fewer complications, and we believe that routine application of this procedure will lead to reduced morbidity in patients receiving coronary artery bypass surgery, short hospital stay and early convalescence, combined with good cosmetic results.

Minimally invasive surgical treatment of coronary artery multivessel disease

BACKGROUND

If coronary artery multivessel disease is the target of a minimally invasive procedure, either median sternotomy or cardiopulmonary bypass can be avoided.

METHODS

We used an alternate technique instead of minithoracotomy and cardiopulmonary bypass to treat 102 patients (82 men, 20 women; age range, 39 to 82 years; median, 61.0 +/- 8.9 years) for coronary artery single-vessel, double-vessel, or multivessel disease between November 1996 and January 1998. Twenty-nine patients (22 men, 7 women; age range, 46 to 78 years; median, 69.0 +/- 8.4 years), who were in a high-risk group for the development of perioperative complications because of the use of cardiopulmonary bypass, received median sternotomy and a beating heart procedure using the Octopus stabilizing technique. The left anterior descending coronary artery was the target vessel in all patients except for 1, in whom the left internal mammary artery was used.

RESULTS

There was no intraoperative death in either series. In the beating heart group (Octopus) 2 patients died on postoperative day 31 and 35, respectively, of postoperative pneumonia.

CONCLUSIONS

Both techniques present safe alternative procedures to conventional coronary artery bypass grafting in patients with coronary artery multivessel disease.

German health care reform: the next steps

From the U.S. perspective, the German health care system offers much to be desired: universal access, moderate costs, and freedom of choice. The Germans consider their health care system to be in crisis, however, because the mechanisms on which they currently rely for financing and paying for health care, as well as the structures through which medical care is delivered, seem increasingly less viable. Germany has recently adopted modest reforms to partially address these problems. For longer term solutions, however, some in Germany are looking to U.S. managed care models, for better or for worse.

Contact allergy to Manilla resin. Nomenclature and physico-chemistry of Manilla, kauri, damar and copal resins

16 cases of allergic eczema from a resin used in a surgical adhesive (Alphacopal) are described. Because of the extreme confusion regarding the nomenclature and origin of the resins called copals and damars, this report attempts to give a terminological, botanical, physico-chemical and allergological restatement of this problem. Copals and damars are produced by trees belonging to the Araucariaceae, Caesalpiniaceae, Dipterocarpaceae and Burseraceae families. We suggest that the word "copal" be reserved for the resins of the Caesalpiniaceae and that of "damar" for the resins of the Dipterocarpaceae. The resins of the Araucariaceae are special products that may be called Manilla resin and kauri resin, which are relatively different from each other. As far as the soft resins of the Burseraceae are concerned, it would be appropriate to use the word "elemi". The component resin of the surgical adhesive implicated (Alphacopal) is a Manilla resin, produced by a variety of Agathis dammara (Lamb.) Rich., native to the Philippines. We suggest 3 allergen screening series. Finally 2 pseudo-cross-sensitivities are mentioned.

Production and characterization of monoclonal antibodies against recombinant human tumor necrosis factor/cachectin

Tumor necrosis factor is a monokine, which causes cytolysis of many transformed cells. In this study we have found that in addition to cytotoxicity recombinant Escherichia coli-derived human tumor necrosis factor, like cachectin, inhibited the lipoprotein lipase of 3T3-L1 preadipocytes. Both effects were inhibited by monoclonal anti-tumor necrosis factor antibodies. Monoclonal antibodies against recombinant human tumor necrosis factor were produced by fusing splenocytes of immune mice with P3X63Ag8 653 myeloma cells. The monoclonal antibodies, namely BG 2-4, were of IgG2a, IgG, and IgG2a subclasses. These monoclonal antibodies neutralized the cytotoxicity of natural and recombinant human tumor necrosis factor but not that of rabbit or mouse tumor necrosis factor. They also neutralized the cachectin activity of human tumor necrosis factor in the 3T3-L1 embryonic cell assay. These results indicate that the functional structure(s) of human tumor necrosis factor responsible for the cytotoxicity and cachectin activities are likely to be closely related.

Study of antigenic epitopes recognized by monoclonal antibodies to recombinant interferon-gamma

Seven hybridomas (BG 1-7) which secreted monoclonal antibodies against recombinant interferon-gamma were produced. The ascites fluids containing four of the seven monoclonal antibodies (BG 1-4) neutralized the antiviral activity of both natural and recombinant interferon-gamma. Competition between labeled and unlabeled monoclonal antibodies for interferon-gamma in a solid phase immunoassay showed that BG 1 was competed by both BG 3 and BG 4 but not by BG 2; BG 2 was competed by BG 3 but not by BG 1 nor by BG 4. These results suggest that human interferon-gamma has at least two antigenic epitopes; one of the epitopes reacted with BG 1 & BG 4 while the other reacted with BG 2; BG 3 either binds to a region overlapping with the other two epitopes or reacts with both epitopes. The antigenic epitopes recognized by these four neutralizing monoclonal antibodies are likely at or closely related to the active sites of interferon-gamma.

Bone grafts with surface decalcified allogeneic and particulate autologous bone: report of cases

A method for mandibular bone grafting that uses a combination of SDAB and particulate autologous cancellous bone and marrow is presented. The results of this treatment in four patients are described. Two additional maxillary bone grafts that use only SDAB are also reported. Grafts that are a combination of SDAB and cancellous autologous bone and marrow are biocompatible, anatomically contoured, easily adapted at surgery, and the allogeneic component is biodegradable. They do not require elaborate internal metallic devices for structural support.