Fullerene quantum gyroscope

We report the observation of quantized rotational states of a diatomic C2 unit in solid endohedral fullerene C(2)Sc(2)@C(84). The rotational transitions induce a periodic line pattern in the low energy Raman spectrum. The rotational constant B and the C-C distance were found to be 1.73 cm(-1) and 0.127 nm, respectively. Density functional calculations revealed an intrinsic rotational barrier of the order of only a few meV for the C2 unit. The Schrödinger equation involving the potential barrier was solved and the Raman tensor matrix elements were calculated, yielding good quantitative agreement with the experiment. To our best knowledge this is the first intrinsic rotational spectrum of a diatomic plane molecular rotor.

Sympathetic and parasympathetic activation in heart rate variability in male hypertensive patients under mental stress

Disturbed sympathetic and also parasympathetic activity of the autonomic nervous system points to pathological alterations in the cardiovascular system. Untreated hypertensive subjects were examined with respect to the question of whether an increase in sympathetic activity necessarily goes along with a reduction in parasympathetic activity, and whether 'delayed' recovery behaviour after mental stress could be an indicator of a disturbed cardiovascular function. In 20 male hypertensive (HT) and 20 normotensive (NT) subjects (control group), heart rate variability (HRV) was compared during rest and under mental stress. The testing procedure consisted of the following phases: habituation, arithmetic tasks without and with interference, recovery. HRV was analysed using the trigonometric regressive spectral analysis (TRS). Proceeding from the total variance (ms2), the weighted averaged frequency (Hz) and the variance parts (ms2) in the frequency bands 'low frequency' (LF-band: 0.04-0.15 Hz) and 'high frequency' (HF-band: 0.15-0.40 Hz) were explored. The variance part modulated by spontaneous breathing within the HF-band was assessed additionally. The variance part in the LF-band under mental stress was significantly increased in the HT group (P<0.01). Activity in the HF-band (without the respiration-dependent part) under mental stress did not differ between both groups, whereas the breathing-modulated part of variance in the HF-band was reduced in the HT subjects. During the recovery period in the HT group, the weighted averaged frequency was still elevated compared to baseline, and the variance part in the LF-band was increased, which may point to delayed recovery behaviour. In addition, by using a discriminant analysis 85% of all subjects were reclassified to the original groups, all HT subjects being assigned 'correctly'. Spectral variance parameters enable early discovery of altered cardiovascular regulation. Respiration influences variance in the HF-band in hypertensive subjects and should therefore be paid attention to. The variance part in the LF-band, weighted averaged frequency and the respiration-modulated variance in the HF-band turned out to be the most valid parameters for the differentiation between NT and HT subjects.

Chronic Necrotizing Pulmonary Aspergillosis Complicated by Pneumothorax

A 61-year-old man presented with left-sided pneumothorax. On the chest computed tomograghy (CT), severe bilateral emphysema and left-sided pleural thickening were seen. His pneumothorax was drained with a chest tube. Because of a persistent air leakage, video-thoracoscopic wedge-resection of the suspected fistula and muscle-sparing minithoracotomy with extensive wedge resections of the left upper lobe were performed. Biopsy specimens showed micronodular mycetomas with septate hyphae highly suggestive of Aspergillus. The fungus destructed the lung tissue without vessel invasion. The patient had not been taking immunosuppressant drugs and had no prior opportunistic infections. Itraconazole was begun, the lung was expanded and the patient recovered. We propose that extensive resection of affected lung tissue in combination with long-term antifungal therapy with itraconazole is a valuable therapeutic option in patients with a complicated course of chronic necrotizing pulmonary aspergillosis (CNPA).

Adjuvant inhibition of the epidermal growth factor receptor after fractionated irradiation of FaDu human squamous cell carcinoma

BACKGROUND AND PURPOSE

Experiments performed by others have shown that inhibition of EGFR before and after single dose irradiation prolonged growth delay and improved local tumour control. This suggests that adjuvant EGFR inhibition can inactivate clonogens that survived irradiation. To test this hypothesis local tumour control was investigated after fractionated radiotherapy and adjuvant EGFR-TK inhibition.

MATERIALS AND METHODS

FaDu hSCC xenografts were irradiated with 30 fractions in 6 weeks with total doses of 30-100Gy. After the end of fractionated irradiation, BIBX1382BS was administered daily orally over a time period of 75 days. Tumour volumes were determined two times per week, the volume doubling time during adjuvant treatment was calculated for progressing and recurrent tumours. Local tumour control was investigated 120 days after end of irradiation.

RESULTS

Adjuvant BIBX1382BS significantly reduced the tumour growth rate but did not improve local tumour control. The TCD(50) values were 66.1Gy (95% C.I.: 59; 73Gy) after adjuvant BIBX1382BS treatment and 67.9Gy (61; 75Gy) for control tumours (P=0.9).

CONCLUSIONS

These data indicate that, although growth of recurrent tumour cells after irradiation is dependent on the EGFR pathway, tumour cells retain their clonogenic potential despite of EGFR inhibition. The results imply also that a decreased tumour growth rate does not necessarily allow conclusions on enhanced inactivation of clonogenic cells when antiproliferative drugs are combined with radiation.

4-(omega-(alkyloxy)alkyl)-1H-imidazole derivatives as histamine H(3) receptor antagonists/agonists

In an effort to develop new histamine H(3) receptor antagonists usable as pharmacological tools we present here novel unsymmetrical ether derivatives. Etherification of different omega-(1H-imidazol-4-yl)alkyl scaffolds led to compounds containing alkyl chains of increasing lengths either with or without unsaturated termini, cycloalkyl or arylalkyl moieties, or additional heteroatoms. When investigated in an in vitro assay on rat synaptosomes, the majority of compounds displayed potencies in the low nanomolar concentration range at the H(3) receptor, e.g., 4-(3-(3-cyclopentylpropyloxy)propyl)-1H-imidazole (27, K(i) = 7 nM). FUB 465, 4-(3-(ethoxy)propyl)-1H-imidazole (14), a useful tool for the characterization of constitutive activity of H(3) receptors in vivo in rodents, proved to be of high oral in vivo potency in mice (ED(50) = 0.26 mg/kg). Further, the influence of chosen compounds on specific [(35)S]GTPgammaS binding was assayed on HEK293 cell membranes expressing the human histamine H(3) receptor revealing partial agonism of the compounds in this particular model. These distinct responses are further hints for "protean agonism" in this class of compounds. Additionally, selected compounds were functionally investigated in vitro on isolated organs of the guinea-pig at H(3), H(1), and H(2) receptors.

Insulinoma-Associated Protein IA-2, a Vesicle Transmembrane Protein, Genetically Interacts with UNC-31/CAPS and Affects Neurosecretion in Caenorhabditis elegans

IA-2 (insulinoma-associated protein 2), a major autoantigen in type 1 diabetes, is a receptor-tyrosine phosphatase-like protein associated with the membrane of secretory granules of neural and endocrine-specific cells. Loss of IA-2 activity in the mouse results in reduced insulin release and additional phenotypes, consistent with a general effect on neurosecretion and hormone release. To gain further insight into the cellular mechanisms of IA-2 function, we have studied the Caenorhabditis elegans homolog, CeIA-2 encoded by the ida-1 gene. Using two independent putative null alleles of ida-1, we demonstrate that animals lacking CeIA-2 activity are viable and exhibit subtle defects. Genetic studies of mutants in ida-1 and several genes involved in neurosecretory vesicle cargo release and signaling highlight two roles for CeIA-2. First, CeIA-2 has a specific and novel genetic interaction with UNC-31/CAPS, a protein that has been shown in other systems to regulate dense-core vesicle cargo release. Second, loss of CeIA-2 activity enhances weak alleles in the insulin-like signaling pathway. These results suggest that CeIA-2 may be an important factor in dense-core vesicle cargo release with parallels to insulin signaling in mammals.

Facial expression recognition and subthalamic nucleus stimulation

BACKGROUND

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves motor signs in Parkinson's disease. However, clinical studies suggest that DBS of the STN may also affect cognitive and emotional functions.

OBJECTIVE

To study the impact of STN stimulation in Parkinson's disease on perception of facial expressions.

RESULTS

There was a selective reduction in recognition of angry faces, but not other expressions, during STN stimulation.

CONCLUSIONS

The findings may have important implications for social adjustment in these patients.

Repopulation of moderately well-differentiated and keratinizing GL human squamous cell carcinomas growing in nude mice

PURPOSE

It has been suggested that, reminiscent of the regulated proliferative response of normal squamous epithelium, squamous cell carcinomas that have preserved characteristics of differentiation have a greater repopulation capacity during fractionated irradiation than undifferentiated tumors. The aim of the present study was to investigate repopulation in moderately well-differentiated and keratinizing GL human squamous cell carcinomas in nude mice.

METHODS AND MATERIALS

GL human squamous cell carcinomas were transplanted s.c. into the right hind leg of NMRI nu/nu mice. Irradiation was performed with 5.4 Gy fractions under clamp hypoxia or with 2 Gy fractions under ambient conditions. Six, 12, or 18 fractions were given daily, every second day, or every third day. Graded top-up doses were applied under clamp hypoxia to determine the tumor control dose 50% (TCD(50)). A total of 20 TCD(50) assays were performed and analyzed using maximum-likelihood techniques.

RESULTS

With an increasing number of daily 5.4 Gy fractions under clamp hypoxia, the top-up TCD(50) values decreased significantly from 50.9 Gy (95% CI: 47, 54) after single doses to 0 Gy after 18 fractions. For the same number of fractions, the top-up TCD(50) increased with increasing overall treatment time. The results are consistent with a constant repopulation rate with a clonogenic doubling time (T(clon)) of 12.7 days (8.6, 16.8). Under ambient blood flow, the top-up TCD(50)s for daily 2 Gy fractions decreased significantly, but were less pronounced than for 5.4 Gy fractions under clamp hypoxia. For a given number of fractions under ambient conditions, the top-up TCD(50)s did not increase significantly with overall treatment time, except for irradiation with 12 fractions in 36 days compared to 12 and 24 days. The T(clon) value from these data was 24.0 days (11.6, 36.4).

CONCLUSION

Our data demonstrate a slow but significant rate of repopulation of clonogenic tumor cells during fractionated irradiation of GL human squamous cell carcinomas under clamp hypoxia without indication of a change of the repopulation rate during treatment. Less pronounced repopulation was observed for irradiation under ambient conditions, which might be explained by preferential survival of hypoxic and therefore nonproliferating cells. Taken together with our previous studies on poorly differentiated FaDu tumors (Petersen et al., IJROBP 2001;51:483-493), the results support important heterogeneity of kinetics and mechanisms of repopulation, in particular of the influence of the oxygenation status of surviving clonogenic cells on the repopulation rate during fractionated irradiation, in different experimental squamous cell carcinoma.

Viability of the myocardium after twenty-four-hour heart conservation--a preliminary study

BACKGROUND

Orthotopic heart transplantation following ischemic times beyond four hours is associated with increased risk of early graft failure. The use of modern myocardial preservation strategies could enable safe transplantation after long-term conservation. In this study, we tested a new myocardial protection regime in an experimental model of 24 h storage.

METHODS

Orthotopic heart transplantations (n=15) were performed in a pig model. Donor hearts were flushed with Bretschneider solution, excised, and stored for 24 hours at 4 degrees C. During implantation, controlled reperfusions with substrate-enriched leukocyte-depleted blood cardioplegia were performed after each anastomosis. Blood cardioplegia contained 1 mmol/l of the Na(+)-H(+)-exchange inhibitor HOE 642 and 100 mg/l of adenosine. Controlled reperfusion was continued with leukocyte-depleted blood for 20 min. A microaxial pump was inserted after heart transplantation and circulatory assistance was maintained for five hours to prevent right heart failure.

RESULTS

No initial graft failure could be observed. Thirteen hearts could be weaned from extracorporeal circulation. Due to bleeding problems, kidney and lung failure only five hearts could be included in the final analysis. Hemodynamics of these hearts remained stable with epinephrine at 0.1 micro g/kg/min. Myocardial oxygen consumption 20 min after start of reperfusion (5.3+/-2.0 ml/100 g/min) did not differ significantly versus baseline (6.8+/-2.0 ml/100 g/min). Oxygen extraction six hours after heart transplantation was also well preserved compared to baseline (58.0+/-10.2 versus 49.2+/-8.8 %). Histological examination six hours after transplantation using luxol fast blue staining revealed that only 1.0 % of the myocytes were irreversibly damaged.

CONCLUSIONS

The data indicate full viability of the myocardium after 24 h conservation. The preservation technique described could contribute to the extension of conservation times in heart transplantation and enable transplantation of marginal donor hearts.

Multipole induced splitting of metal-cage vibrations in crystalline endohedral D2d-M2@C84 dimetallofullerenes

Metal-carbon cage vibrations of crystalline endohedral D2d-M2@C84 (M=Sc,Y,Dy) dimetallofullerenes were analyzed by temperature dependent Raman scattering and a dynamical force field model. Three groups of metal-carbon cage modes were found at energies of 35-200 cm(-1) and assigned to metal-cage stretching and deformation vibrations. They exhibit a textbook example for the splitting of molecular vibrations in a crystal field. Induced dipole-dipole and quadrupole-quadrupole interactions account quantitatively for the observed mode splitting. Based on the metal-cage vibrational structure it is demonstrated that D2d-Y2@C84 dimetallofullerene retains a monoclinic crystal structure up to 550 K and undergoes a transition from a disordered to an ordered orientational state at a temperature of approximately 150 K.

[Mechanical circulatory assist devices in acute and chronic heart failure]

The clinical use of mechanical circulatory assist devices as bridge to transplantation has been proved as life-saving therapy in a large population of patients. Learning from the clinical experience the construction of the blood pumps has been markedly improved over the last years. The better outcome of the patients has enabled a broader use of ventricular assist devices. The novel axial pumps are designed for long-term circulatory support. After further reduction of device related complications (first of all thromboembolic events) these systems may provide a future alternative to heart transplantation.

Proliferation and micromilieu during fractionated irradiation of human FaDu squamous cell carcinoma in nude mice

PURPOSE

Previous functional radiobiological experiments demonstrated a significant acceleration of repopulation after 3 weeks and reoxygenation after 12 days of radiotherapy of FaDu tumours. Owing to the temporal coincidence between repopulation and reoxygenation, it was hypothesized that the improved oxygenation status during fractionated irradiation might be the preceding stimulus for increased proliferation. The study investigated whether these changes in repopulation and re-oxygenation are reflected by histological parameters of proliferation and the tumour micromilieu.

MATERIALS AND METHODS

Human FaDu squamous cell carcinomas in nude mice were irradiated with three to 18 fractions of 3 Gy daily or every second day under normal blood flow and clamp hypoxia. At different time points, tumours were excised and stained for Ki67, BrdUrd, epidermal growth factor receptor (EGFR) and markers of the micromilieu (HOECHST 33342, pimonidazole, ER-MP12).

RESULTS

On average, Ki67 and BrdUrd labelling indices decreased initially and increased again at later times during the course of fractionated radiotherapy. A similar kinetic pattern was found for the staining intensity of the EGFR. The vascular density in the viable tumour area remained constant during the whole course of irradiation, while the perfused fraction of vessels decreased within the first week of irradiation and returned to baseline values after 2 weeks. There was a corresponding increase in perfusion and a decrease in cellular hypoxia.

CONCLUSIONS

The histological results were in surprisingly good agreement with the kinetics of clonogen repopulation and re-oxygenation determined previously using functional assays. The results support that the kinetics of repopulation of FaDu squamous cell carcinoma in response to fractionated irradiation are determined not only by intracellular processes, but also by a complex interaction of proliferation parameters with a changing microenvironment.