[Development and study of structure-activity relationship of drugs against Mycobacterium tuberculosis]

Tuberculosis is considered to be one of the major health problem not only in the less developed countries but in the economically developed countries as well. Roughly one third of the world's population are infected with Mycobacterium tuberculosis and a significant part of them are carriers of latent tuberculosis. From ten percent of these latent infections are developing the active TB disease and fifty percent of them die from the illness without appropriate treatment. The drug-resistant Mycobacterium tuberculosis (MDR-TB, XDR-TB) and TB-HIV co-infection attracted attention to the most serious infectious disease. Inhibition of alternative signaling pathways were an important part of the research strategies for cancer and inflammatory diseases in recent years. In case of Mycobacterium tuberculosis such pathways were also identified, for example, three serine-threonine kinases (PknA, PknB, PknG) which are necessary and essential for bacterial growth. In this paper we summarize our best anti-TB active compounds, their biological effects and structure-activity relationships using in silico modeling, biochemical measurements and tests on active bacteria.

[Developing FGFR inhibitors as potential anti-cancer agents]

Fibroblast Growth Factor Receptor (FGFR) family is a sequentially highly related subgroup of membrane proteins consisting of four tyrosine kinase type enzyme: FGFR1, FGFR2, FGFR3 and FGFR4. These are kinases of great interest in a wide spectrum of physiological processes such as tissue repair via controlling cell proliferation. As initiatiors of cell proliferation, in some cases they have leading roles in several types of cancer, eg. breast cancer, pancreas cancer, gastric tumors and multiple myeloma via overexpression and/or mutation. This phenomenon makes them promising targets for drug development in order to develop signal transduction therapies based on small molecule FGFR inhibitors. We have developed two main groups of lead molecules: compounds with benzotiophene and oxindole cores utilizing numerous methods from in silico modelling via in vitro biochemichal assays and testing on relevant cell lines to cytotoxicity assays.

Novel, selective CDK9 inhibitors for the treatment of HIV infection

Cyclin Dependent Kinases (CDKs) are important regulators of cell cycle and gene expression. Since an up-to-date review about the pharmacological inhibitors of CDK family (CDK1-10) is not available; therefore in the present paper we briefly summarize the most relevant inhibitors and point out the low number of selective inhibitors. Among CDKs, CDK9 is a validated pathological target in HIV infection, inflammation and cardiac hypertrophy; however selective CDK9 inhibitors are still not available. We present a selective inhibitor family of CDK9 based on the 4-phenylamino-6- phenylpyrimidine nucleus. We show a convenient synthetic method to prepare a useful intermediate and its derivatisation resulting in novel compounds. The CDK9 inhibitory activity of the derivatives was measured in specific kinase assay and the CDK inhibitory profile of the best ones (IC(50) < 100 nM) was determined. The most selective compounds had high selectivity over CDK1, 2, 3, 5, 6, 7 and showed at least one order of magnitude higher inhibitory activity over CDK4 inhibition. The most selective molecules were examined in cytotoxicity assays and their ability to inhibit HIV-1 replication was determined in cellular assays.

Comparison of anterior chamber depth measurements conducted with Pentacam HR® and IOLMaster®

BACKGROUND AND OBJECTIVE

Anterior chamber depth (ACD) is an important anterior segment parameter. This study compared ACD measurements conducted with two optical devices in phakic, emmetropic eyes.

PATIENTS AND METHODS

Eighty-three phakic eyes of 44 patients with a mean axial length of 23.06 ± 0.94 mm were enrolled in the study. ACD was measured three times with the Scheimpflug-based Pentacam HR (Oculus, Wetzlar, Germany), then three times with IOLMaster (Carl Zeiss Meditec, Dublin, CA), and data were statistically analyzed.

RESULTS

The measurements resulted in a mean ACD of 3.01 ± 0.34 mm with Pentacam HR and 2.95 ± 0.32 mm with IOLMaster. Distribution of data was normal, and no significant difference in ACD values was detected (P = .29) between the two devices. Correlation between ACD measurements was highly significant (r = 0.85; P < .0001).

CONCLUSION

In phakic eyes, ACD measured with Pentacam HR and with IOLMaster showed similar values, and high correlation was observed between these two devices.

Spectroscopic study of explanted opacified hydrophilic acrylic intraocular lenses

PURPOSE

To report a detailed spectroscopic analysis of explanted hydrophilic acrylic intraocular lenses (IOLs) that were removed because of postoperative opacification of the lens optic.

METHODS

Thirteen Hydroview H60M (Bausch & Lomb Surgical) IOLs were explanted from 13 different patients on average 56 months after phacoemulsification and IOL implantation. All patients had decreased visual acuity because of a fine granularity of the optical surface of the IOLs. The surface was investigated by gross, microscopic, histochemical and scanning electron microscopic analysis, and the elemental composition of the opacified IOLs was determined by X-ray fluorescence spectroscopy (XRF). The spectrograms were compared to three different originally packed and never-implanted hydrophilic acrylic IOLs.

RESULTS

Light and scanning electron microscopy of the optical surface of explanted IOLs revealed multiple fine granular deposits varying in size and shape that were positive for alizarin red. XRF confirmed that the explanted IOLs contained not only the previously reported calcium and phosphorous (calcium apatite), chlorine, silicone, sodium, aluminum and magnesium but also iron, sulfur, potassium as well as lesser amounts of iodine, zinc, strontium and yttrium.

CONCLUSION

This is the first spectroscopic analysis determining the content of more than 10 elements of explanted and originally packed never-implanted hydrophilic acrylic IOLs. The possible origin of the different elements obtained from the spectrograms and their implications are discussed.

Evaluation of a recently developed noncontact specular microscope in comparison with conventional pachymetry devices

PURPOSE

The study was conducted to assess the central corneal thickness (CCT) of the healthy cornea with a recently developed noncontact specular microscope (EM-3000; Tomey) and compare the results with those measured with a contact specular microscope and an ultrasound pachymeter. Agreement between measurements taken by 2 investigators was also studied.

METHODS

The right eyes of 41 healthy individuals who had negative history of contact lens wear, ophthalmic disease, or ocular surgery were examined. The CCT was determined sequentially with a noncontact specular microscope, a contact specular microscope (EM-1000; Tomey), and an ultrasound pachymeter (AL-2000; Tomey). Each evaluation with the specular microscopes was performed by 2 independent operators.

RESULTS

A significant difference was detected in pachymetry measurements among the 3 instruments (p=0.01; analysis of variance). The mean CCT values were lower measured with the ultrasound pachymeter (537+/-30 microm) than the contact endothelial microscope (543+/-37 microm, p=0.17, Student t-test) and the noncontact microscope (549+/-33 microm, p<0.0001) (operator 1). There was no statistically significant difference in CCT measurements between the 2 endothelial microscopes (p=0.19). We found significant correlations (p<0.0001) in thickness measurements between each pair of instruments (r=0.91, noncontact microscopy and ultrasound pachymetry; r=0.74, noncontact and contact microscopy; r=0.72, contact microscopy and ultrasound pachymetry; Spearman rank correlation).

CONCLUSIONS

The strong correlations among the 3 pachymetry devices suggest that the tested instruments provide reliable measurements; however, they cannot be used interchangeably.

[Synthesis of 4-Chloro-6-(substituted-phenyl)-pyrimidines]

4-Phenylamino-6-phenyl-pyrimidine is a common core structure of several, important enzyme inhibitors. The common key intermediate of these compounds, 4-chloro-6-substituted phenyl pyrimidine, was synthesised by conventional methods without the application of special catalysts in contrary to the published methods. Here we present two different synthetic procedures for the preparation of the title compound. The results of these processes depend on the substituent of the 6-phenyl ring as it is demonstrated on the presented examples. The reactions can be performed via traditional heating either with microwave assistance.

Detection of hydrogen peroxide by lactoperoxidase-mediated dityrosine formation

The aim of this work was to study the dityrosine-forming activity of lactoperoxidase (LPO) and its potential application for measuring hydrogen peroxide (H2O2). It was observed that LPO was able to form dityrosine at low H2O2 concentrations. Since dityrosine concentration could be measured in a simple fluorimetric reaction, this activity of the enzyme was utilized for the measurement of H2O2 production in different systems. These experiments successfully measured the activity of NADPH oxidase 4 (Nox4) by this method. It was concluded that LPO-mediated dityrosine formation offers a simple way for H2O2 measurement.

[Examination of accommodation in pseudophakic eyes]

Some patient with monofocal intraocular lens can achieve good near visual acuity with distance correction after cataract surgery. Understanding and measuring this phenomenon also called pseudoaccommodation can help to develop new technology to substitute or restore accommodation in pseudophakic eyes.

AIM

I. To measure accommodation after cataract surgery. II. To measure anterior chamber depth with Scheimpflug imaging and comparing results with standard, ultrasonic data. III. To compare anterior chamber depth data, repeatability, reproducibility and reliability with a new optical device, the anterior segment optical coherent tomography (Visante OCT) and immersion ultrasound method in phakic eyes.

METHODS

I. We observed accommodation with defocusing technique, partial coherent interferometry method and measuring anterior chamber depth changing during ciliary muscle blocking. II. We measured anterior chamber depth with Pentacam and data were compared to standard ultrasonic method in phakic and pseudophakic eyes. III. We analyzed anterior chamber depth data, repeatability, reproducibility and reliability obtained by two observers using Visante OCT.

RESULTS

I. A total accommodation amplitude of 0,83 D was observed with defocusing technique. Intraocular lens movement were negligible measured by partial coherent interferometry method using physiological accommodation stimulus. Mean movement of intraocular lens was 0.18 mm during blocking of the ciliary muscle. II. Pentacam and ultrasonic device measure the same anterior chamber depth in phakic eyes, but in pseudophakic eyes optical method measures significantly shallower anterior chamber depth. III. Anterior segment optical coherent tomography measures deeper anterior chamber depth than immersion ultrasonic device in phakic eyes.

CONCLUSIONS

Accomodation and pseudoaccommodation observed in pseudophakic eyes is hard to measure and only parts of this process can be measured with each technique. Anterior chamber depth data varies by the measuring technique. Repeatability, reproducibility and reliability of anterior chamber depth data were better with optical technique.

Health-related quality of life (EQ-5D) before and one year after surgery for lumbar spinal stenosis

We investigated the pre-operative and one-year post-operative health-related quality of life (HRQoL) outcome by using a Euroqol (EQ-5D) questionnaire in 230 patients who underwent surgery for lumbar spinal stenosis. Data were obtained from the National Swedish Registry for operations on the lumbar spine between 2001 and 2002. We analysed the pre- and postoperative quality of life data, age, gender, smoking habits, pain and walking ability. The relative differences were compared to a Swedish EQ-5D population survey. The mean age of the patients was 66 years, and there were 123 females (53%). Before the operation 62 (27%) of the patients could walk more than 500 m. One year after the operation 150 (65%) were able to walk 500 m or more. The mean EQ-5D score improved from 0.36 to 0.64, and the HRQoL improved in 184 (80%) of the patients. However, they did not reach the level reported by a matched population sample (mean difference 0.18). Women had lower pre- and post-operative EQ-5D scores than men. Severe low back pain was a predictor for a poor outcome.

A novel drug discovery concept for tuberculosis: inhibition of bacterial and host cell signalling

The Mycobacterium tuberculosis genome encodes for eleven eukaryotic-like Ser/Thr protein kinases. At least three of these (PknA, PknB and PknG) are essential for bacterial growth and survival. PknG is secreted by pathogenic mycobacteria, in macrophages to intervene with host cell signalling pathways and to block the fusion of the lysosomes with the phagosome by a still unknown mechanism. Based on our previously published results, we have initiated a drug discovery program, aiming to improve the potency against PknG and the physiochemical properties of the initially identified hit compound, AX20017, from the class of the tetrahydrobenzothiophenes. We have established a radioactive biochemical PknG kinase assay to test the novel analogues around AX20017. We have developed lead molecules with IC50 values in nanomolar range, and demonstrated their antituberculotic effects on human macrophages. Selected leads might ultimately serve the purpose of inducing phagosomal-lysosomal fusion and therefore destroy the residence of the intracellular mycobacteria. It is unclear at this time if these "homeless" mycobacteria are getting killed by the host, but they will be at least vulnerable to the activity of antimycobacterial agents. Released mycobacteria rely on the essential function of PknB for survival, which is our second molecular kinase target. PknB is a transmembrane protein, responsible for the cell growth and morphology. We have screened our library and synthesized novel compounds for the inhibition of PknB. A pharmacophore model was built and 70,000 molecules from our synthesizable virtual library have been screened to identify novel inhibitor scaffolds for the generation of templated compound libraries. Currently, we are using a radioactive kinase assay employing GarA as the putative, physiological substrate of PknB kinase. We have identified hits and generated optimised hit compounds with IC50 values for the inhibition of PknB in the nanomolar range. Yet those promising hits are not potent enough to yield meaningful "minimum inhibitory concentrations" in mycobacterial growth assays. In the course of our future work, we will increase the potency of the next generation of PknB inhibitors in order to improve their antibacterial activity.

Anterior segment changes with age and during accommodation measured with partial coherence interferometry

PURPOSE

To evaluate anterior segment alterations with age and during accommodation in different age groups.

SETTING

Department of Ophthalmology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary.

METHODS

Fifty-three subjects (101 normal eyes) were enrolled in this study and divided into 3 age groups: younger than 30 years (Group 1), between 31 years and 44 years (Group 2), and older than 45 years (Group 3). The total amplitude of accommodation was determined with a defocusing technique, and anterior segment measurements were performed by partial coherence interferometry.

RESULTS

Group 1 comprised 32 eyes; Group 2, 37 eyes; and Group 3, 32 eyes. The total amplitude of accommodation decreased with age (P<.0001). With the target position at infinity, the lens thickness (LT) and anterior segment length (ASL) increased and the anterior chamber depth (ACD) decreased significantly with age (P<.0001). During accommodation in the youngest group, the mean change in LT was 36.3 mum/diopter (D) and in ACD, -26.7 mum/D. The mean accommodation-induced ACD change was -0.08 mm +/- 0.06 (SD) in Group 1, -0.064 +/- 0.087 mm in Group 2, and -0.03 +/- 0.06 mm in Group 3 (P = .0004). The mean LT change during near fixation was 0.109 +/- 0.063 mm in Group 1, 0.103 +/- 0.136 mm in Group 2, and 0.006 +/- 0.05 mm in Group 3 (P<.0001). The mean ASL change during accommodation was 0.029 +/- 0.037 mm, 0.039 +/- 0.114 mm, and -0.023 +/- 0.051, respectively (P<.0001).

CONCLUSIONS

In addition to forward movement of the anterior lens surface with age, the posterior surface moved backward. Alterations in LT and ACD sufficient for a unit of refractive power change during accommodation might be smaller than previously thought. Anterior shifting of the lens may also participate in the accommodative response.

Pseudophakic accommodation and pseudoaccommodation under physiological conditions measured with partial coherence interferometry

PURPOSE

To distinguish pseudophakic accommodation from pseudoaccommodation by measuring the physiologically and pharmacologically induced anterior chamber depth (ACD) shifts.

SETTING

Department of Ophthalmology, University of Debrecen, Debrecen, Hungary.

METHODS

This study comprised 100 pseudophakic eyes of 79 patients. Forty patients (Group 1) received the AcrySof MA60AC intraocular lens (IOL) (Alcon Laboratories), 50 patients (Group 2) received the SA60AT IOL (Alcon Laboratories), and 10 patients (Group 3) received the apodized diffractive SA60D3 ReSTOR IOL. Visual function was evaluated a mean of 10.2 months +/- 9.2 (SD) postoperatively, and the total pseudoaccommodative amplitude was determined with a defocusing technique. To distinguish pseudophakic accommodation from pseudoaccommodation, ACD measurements were performed using partial coherence interferometry during distance fixation and physiologic accommodation after pharmacologic relaxation of the ciliary muscle.

RESULTS

Best corrected distance and near visual acuities were similar in the 3 groups (P = .75 and P = .08, respectively). Distance corrected near visual acuity was significantly better in Group 3 (P < .001), with all eyes achieving J1 or better. Three percent in Group 1 and 8% in Group 2 achieved J1 or better. Subjective accommodation was similar in Groups 1 and 2 (-0.82 +/- 0.18 diopter [D] and -1.00 +/- 0.35 D, respectively; P = .3). Group 3 had an accommodation curve with 2 peaks. Intraocular lens movement differences between the groups were not significant (physiologic stimulus: P = .07; cyclopentolate: P = .46), and significant ACD shifts from baseline were not detected (physiologic stimulus: P = .14; cyclopentolate: P = .10).

CONCLUSIONS

Pseudoaccommodative amplitude of the investigated monofocal IOLs was independent of IOL movement. Anterior shift did not affect good near visual acuity with the AcrySof ReSTOR IOL.

An illustrative case and a review on the dosing of recombinant factor VIIa in congenital factor XI deficiency

Recombinant activated factor VII (rFVIIa) has been used in a very limited number of patients with severe factor XI (FXI) deficiency. The dose and duration of treatment has varied greatly between these case reports. In a few of these cases there was also evidence of thrombotic complications. We present here a report on one additional patient with congenital FXI deficiency. For two major orthopaedic procedures in this patient we used rFVIIa as a single bolus dose followed by continuous infusion at a low rate. The data from these treatment episodes, together with those from a review of the published cases, lend support to the concept of using much lower doses than in haemophilia with inhibitors. A bolus dose of 20 microg kg(-1) and thereafter maintenance of the FVII activity at approximately 3 IU mL(-1) appears effective and safe.

Corneal endothelial function after phacoemulsification using the fluid-based system compared to conventional ultrasound technique

AIM

To quantitatively assess corneal endothelial changes after phacoemulsification with the fluid-based system compared to conventional ultrasound technique.

METHODS

This prospective, randomized clinical study included patients with cataract who were randomly assigned either to have phacoemulsification with the fluid-based system (30 eyes of 30 patients--Group 1) or with traditional ultrasound (30 eyes of 30 patients--Group 2). Patients who were available at each follow-up visit (25 eyes in both groups) were enrolled in the statistical analysis. Endothelial function was evaluated by measuring central corneal thickness, central endothelial cell density (ECD), mean cell size, and coefficient of variation in cell size preoperatively, 10 days, 1 and 3 months, and 1 year after surgery. Statistical analyses were performed using two-way repeated measure ANOVA.

RESULTS

An acute, reversible increase of central corneal thickness (CCT) was found 10 days after surgery, which was similar in both groups (P=0.35). ECD decreased, whereas mean cell size increased significantly immediately after surgery. However, the impairments were finished after 1 month. The alterations were similar in both groups (ECD: P=0.99; mean cell size: P=0.85). The coefficient of variation in cell size remained stable after surgery (P=0.08), and significant difference was not found between groups (P=0.99). The endothelial cell loss (ECL) was 6.5+/-8.4% in Group 1 and 6.5+/-11.7% in Group 2 (P=0.69).

CONCLUSIONS

Corneal endothelial changes were similar using the fluid-based system compared to the traditional ultrasound technique. The fluid-based method proved to be as safe as conventional ultrasound in cataract surgery.

Health-related quality of life in patients before and after surgery for a herniated lumbar disc

We investigated the pre-operative and one-year post-operative health-related quality of life (HRQOL) outcome by using a Euroqol (EQ-5D) questionnaire in 263 patients who had undergone surgery for herniation of a lumbar disc. Data from the National Swedish Register for lumbar spinal surgery between 2001 and 2002 were used and, in addition, a comparison between our cohort and a Swedish EQ-5D population survey was performed. We analysed the pre- and post-operative quality of life data, age, gender, smoking habits, pain and walking capacity. The mean age of the patients was 42 years (20 to 66); 155 (59%) were men and 69 (26%) smoked. Pre-operatively, 72 (17%) could walk at least 1 km compared with 200 (76%) postoperatively. The mean EQ-5D score improved from 0.29 to 0.70, and the HRQOL improved in 195 (74%) of the patients. The pre-operative score did not influence the post-operative score. In most patients, all five EQ-5D dimensions improved, but did not reach the level reported by an age- and gender-matched population sample (mean difference 0.17). Predictors for poor outcome were smoking, a short pre-operative walking distance, and a long history of back pain.

Surgery for herniation of a lumbar disc in Sweden between 1987 and 1999. An analysis of 27,576 operations

The National Inpatient Register and the Swedish Death Register were linked to determine the incidence of surgical intervention, the trends and characteristics of the patients, the death rate and the pre- and post-operative admissions for herniation of a lumbar disc based on comprehensive national data between 1987 and 1999. There were 27,576 operations which were followed cumulatively for 155,249 years, with a median of 6.0 years. The mean annual rate of operation was 24 per 100,000 inhabitants, the median age of the patients was 42 years. The 30-day death rate was 0.5 per 1000 operations. The rates of re-operation at one and ten years were 5% and 10%, respectively, decreasing significantly (40%) with time. The mean length of stay decreased from nine to five days. Patients who had been in hospital because of a previous spinal disorder had a significantly higher risk of readmission.

The time-course of metastases from breast cancer after mastectomy and breast-conserving surgery with and without isolated local-regional recurrence

We have examined time intervals between events in 390 metastatic breast cancer (MBC) patients whose distant failure developed within 10 years from initial surgery of Stage I/II disease. All of the patients underwent axillary dissection and mastectomy (n=295) or breast-conserving surgery (BCS, n=95), between 1983 and 1987. Distinctions have been made between distant failure with (n=79) and without (n=311) isolated local-regional recurrence (LRR). The median survival time after first relapse was significantly longer with intrabreast (30 months) and chest wall (24 months) than with distant relapse (15 months), but with axillary (17 months) or with supraclavicular (17 months) relapse survival was similar. The delay between LRR and distant metastasis was shorter with axillary (7 months) and supraclavicular (9 months) than with breast (20 months) and chest wall (12 months) recurrences. The median postmetastatic survival time by site of first relapse was significantly shorter with supraclavicular (6 months) and axillary (9 months) than with distant site relapse (15 months) but with intrabreast (12 months) or with chest wall (11 months) recurrence survival was similar. In MBC, regional recurrences are associated with a shorter interval between events than with local recurrences. The shortened intervals for patients with regional recurrence suggest that metastases existed at the time of initial surgery. The question of whether prevention of local or regional recurrence or both improves cause-specific survival after mastectomy or BCS needs to be answered in randomized studies.

Spinal stenosis surgery in Sweden 1987-1999

Despite being recognised for many years as a clinical diagnosis, no exact definition of spinal stenosis has yet been agreed, leading to difficulties in interpreting and comparing studies of the incidence, prevalence and treatment. This study presents the first analysis of national data to be reported. It is a retrospective population-based national register study, aimed at analyzing surgical interventions in patients with lumbar spinal stenosis, patient characteristics, subsequent development, and case fatality rate, based on Swedish national data for 1987-1999. Complete follow-up data were obtained of incidence and type of spinal stenosis surgery, rate of multiple operations, mortality, underlying causes of death, length of hospital stay, and case fatality rate by linkage of the National Inpatient Register and Swedish Death Register. The study cohort consisted of 10,494 patients. Laminectomy was performed in 89%, and additional fusion in 11%. The mean annual rate of operations was 9.7 per 100,000 inhabitants, the annual number of operations performed increased from 4.7 to 13.2 per 100,000 inhabitants per year. The case fatality rate within 30 days after surgery was 3.5 per 1000 operations. Cardiovascular disease was the most common cause of death (46%). Relative risk of dying within 30 days of admission was doubled in men, and for fusion surgery, and increased four fold in patients older than 80 years. The relative risk of dying decreased during the study period. The results show that spinal stenosis surgery in Sweden has increased, and is associated with a low risk. Within an ageing group of patients, mortality has declined.

Methodological concerns using intra-cortical pins to measure tibiofemoral kinematics

The complexity of human tibiofemoral joint motion is now better understood with the advancement of new methodologies to measure tibiofemoral kinematics in vivo. Marker clusters anchored to stainless steel bone pins inserted directly into the femur and tibia provide the most sensitive and accurate means for directly measuring skeletal tibiofemoral joint motion. Despite its invasiveness, this technique has been successful, although complications have been reported with the femoral pin and its insertion site. The purpose of this technical report is twofold: to review the difficulties with the femoral pin and its insertion site from a historical perspective, and to identify the load force required from biological tissue to permanently deform the pin. In addition, proposals in the advancement of this method are discussed in the context of reducing impingement with the femoral pin and the Iliotibial band. Because stainless steel exhibits plastic behaviour with no sharp yield point, Apex self-drilling/self-tapping bone pins underwent incremental loading on an Instron materials testing machine. Loads were transmitted perpendicular to the pin with the threads partially exposed and fully secured in vice. Since the accuracy of our combined stereophotogrammetry and Optoelectric motion analysis was less than 0.4 mm, it was decided that plastic deformation occurred after deflections of 0.4 mm. With exposed threads, deflections larger than 0.4 mm were observed at 150 N and 100 N when loads were applied at 15 mm and 20 mm from the vice (representative of where the tissue came in contact with the pin). Loads greater than 200 N produced deflections less than 0.2 mm when threads were fully inserted. The 90 Hz resonant frequency for the marker cluster-bone pin complex is beyond the spectrum of human movement and can be lowpass filtered. To reduce impingement and pin bending, one solution may be to implant pins with a shorter threaded section. By completely penetrating the bone, only the smooth surface of the pin is exposed which is more resistant to bending. Otherwise pins with larger diameters and longer longitudinal incisions about the femoral insertion site are an alternative. Lengthening the longitudinal incisions about the insertion site, and correctly aligning and inserting the femoral pin between the Iliotibial band and quadriceps tendon may diminish impingement. Performing dynamic open chain flexion and extension movements while on the operating table may aid in aligning the pin at the incision site. This may stretch the IT band and quadriceps tendon and may guide the femoral pin into a more optimal position prior to it being inserted into the cortex of the bone.

Giant clusters in random ad hoc networks

The present paper introduces ad hoc communication networks as examples of large scale real networks that can be prospected by statistical means. A description of giant cluster formation based on a single parameter of node neighbor numbers is given along with the discussion of some asymptotic aspects of giant cluster sizes.

CT densitometry of the brain: a novel method for early detection and assessment of irradiation induced brain edema

The purpose of the study was to examine if the CT densitometric analysis during radiotherapy (RT) of brain tumors is suitable for the early detection of RT induced brain edema (BE), predicting related neurological progress, and assessing the effects of different edema therapies. Planimetric CT-densitograms were constructed by modifying the "High-Lighting" method. Three theoretical density regions were defined and color-coded on the images of the brain. These were defined as edema (10-20 HU), mild edema, and normal brain (29-38 HU). Corresponding axial CT slices were created at the mid-level of the lesion and that of the periventricular white matter to verify the changes in perifocal and diffuse BE. The monitoring was performed on 50 solitary brain tumor patients treated with RT. During RT courses weekly CT-densitometric examinations were carried out. We experienced that changes in densitograms coincided with clinical symptoms, furthermore, preceded the latter. With the use of preventive edema medication based on diuretics and along with adjunctive edema medication adopted to densitograms, the 5-7 week irradiation was completed without ultimate worsening in performance state in 49 of 50 cases and besides we succeeded in avoiding the routine usage of steroids. Based on our findings the CT-densitometry is suitable for early detection and continuous assessment of BE and preventing patient distress during RT. This simple, reproducible and non-invasive procedure could provide an additional clinical tool for new treatment strategies.

[Birth control in antiquity]

Challenges of the overpopulation has been handled by two different ways by ancient Greeks: on the level of the individual and on that of the community respectively. Regarding the so-called micro-social strategies various preventive methods (getting married late, contraception, homosexuality, prostitution, zoophily and the one-child system) but also those of correctional methods were used as well: abortion, killing the new-born or selling him or her as a slave. The author, who is a well-known researcher of the polis system, gives an overview of all these methods. He focuses-by the help of contemporary texts-on the problem of putting out the child, single-child system, late marriage, contraception and abortion.

The role of boost irradiation in the conservative treatment of stage I-II breast cancer

In this article, we review the current status, indication, technical aspects, controversies, and future prospects of boost irradiation after breast conserving surgery (BCS). BCS and radiotherapy (RT) of the conserved breast became widely accepted in the last decades for the treatment of early invasive breast cancer. The standard technique of RT after breast conservation is to treat the whole breast up to a total dose of 45 to 50 Gy. However, there is no consensus among radiation oncologists about the necessity of boost dose to the tumor bed. Generally accepted criteria for identification of high risk subgroups, in which boost is recommended, have not been established yet. Further controversy exists regarding the optimal boost technique (electron vs. brachytherapy), and their impact on local tumor control and cosmesis. Based on the results of numerous retrospective and recently published prospective trials, the European brachytherapy society (GEC-ESTRO), as well as the American Brachytherapy Society has issued their guidelines in these topics. These guidelines will help clinicians in their medical decisions. Some aspects of boost irradiation still remain somewhat controversial. The final results of prospective boost trials with longer follow-up, involving analyses based on pathologically defined subgroups, will clarify these controversies. Preliminary results with recently developed boost techniques (intraoperative RT, CT-image based 3D conformal brachytherapy, and 3D virtual brachytherapy) are promising. However, more experience and longer follow-up are required to define whether these methods might improve local tumor control for breast cancer patients treated with conservative surgery and RT.