Imaging tumors with peptide-based radioligands

Regulatory peptides are small, readily diffusable and potent natural substances with a wide spectrum of receptor-mediated actions in humans. High affinity receptors for these peptides are (over-) expressed in many neoplasms, and these receptors may represent, therefore, new molecular targets for cancer diagnosis and therapy. This review aims to give an overview of the peptide-based radiopharmaceuticals which are presently already commercially available or which are in advanced stages of their clinical testing so that their broader availability is anticipated soon. Physiologically, these peptides bind to and act through G protein-coupled receptors in the cell membrane. Historically, somatostatin analogs are the first class of receptor binding peptides having gained clinical application. 111In-DTPA-[D-Phe1]-octreotide is the first and only radiopeptide which has obtained regulatory approval in Europe and the United States to date. Extensive clinical studies involving several thousands of patients have shown that the major clinical application of somatostatin receptor scintigraphy is the detection and the staging of gastroenteropancreatic neuroendocrine tumors (carcinoids). In these tumors, octreotide scintigraphy is superior to any other staging method. However, its sensitivity and accuracy in other, more frequent neoplasms is limited. Radiolabeled vasoactive intestinal peptide (VIP) has been shown to visualize the majority of gastrointestinal adenocarcinomas, as well as some neuroendocrine tumors, including insulinomas (the latter being often missed by somatostatin receptor scintigraphy). Due to the outstanding diagnostic accuracy of the pentagastrin test in detecting the presence, persistence, or recurrence of medullary thyroid cancer (MTC), we postulated the expression of the corresponding (ie. cholecystokinin [CCK-] -B) receptor type in human MTC. This receptor is also widely expressed on human small-cell lung cancer. Indeed, 111In-labeled DTPA derivatives of gastrin showed excellent targeting of CCK-B receptor expressing tissues in animals and patients. A variety of further peptide-based radioligands, e.g. among many others, gastrin-releasing peptide/bombesin, neurotensin, substance-P, pan-somatostatin (somatostatin derivatives which bind to all five receptor subtypes) or glucagon-like peptide-1 (glp-1) analogs (the latter for the specific detection of insulinomas), is currently under development. Summarizing, radiolabeled regulatory peptides have opened new horizons in nuclear oncology for diagnosis (and potential internal radionuclide therapy). Future work will probably reveal a multitude of novel potentially clinically useful peptide-based radioligands.

The infrared absorption of amino acid side chains

Amino acid side chains play fundamental roles in stabilising protein structures and in catalysing enzymatic reactions. These fields are increasingly investigated by infrared spectroscopy at the molecular level. To help the interpretation of the spectra, a review of the infrared absorption of amino acid side chains in H(2)O and 2H(2)O is given. The spectral region of 2600-900cm(-1) is covered.

Clinical prevalence, antimicrobial susceptibility, and geographic resistance patterns of enterococci: results from the SENTRY Antimicrobial Surveillance Program, 1997-1999

As part of the SENTRY Antimicrobial Resistance Surveillance Program, a total of 4998 strains of enterococci isolated from 1997 to 1999 were processed. The occurrence of enterococcal infections by species and site of infection was analyzed, as were the occurrence of vancomycin-resistant enterococci (VRE) and their resistance phenotypes and genotypes. Trends in antimicrobial susceptibility to a variety of agents (including experimental compounds) were also reported. Enterococci accounted for >9% of isolates from all bloodstream infections (BSIs) in North America. Ampicillin was active against strains from Latin America and Europe but not against those from the United States and Canada. US isolates were considerably more resistant to vancomycin (17% resistant strains in 1999) than were those from patients in the rest of the world. The highest proportion of VRE was observed among BSI isolates (81.7%). Quinupristin-dalfopristin, chloramphenicol, and doxycycline were the most active agents tested against VRE. The results of this study confirm the worldwide trend in increasing occurrence of enterococci and the emerging pattern of antimicrobial resistance among such isolates.

[Chronic anemia and abdominal pain as a sequela of lead poisoning]

HISTORY AND ADMISSION FINDINGS

3 years ago, a 63-year-old man underwent laparotomia due to clinical signs of acute abdominal pain. The anemia was treated with erythrocyte concentrates. Several weeks before the current admission to our outpatient department, the patient was again hospitalized because of acute abdominal pain and anemia. The patient was then transferred to the University clinic for further medical tests.

INVESTIGATIONS

In addition to a normocytic anemia, a secondary porphyria was found. Further medical tests demonstrated lead poisoning.

DIAGNOSIS, TREATMENT AND COURSE

Initially, the cause of the lead poisoning remained unclear because the patient had reported neither an occuppational nor an environmental exposure to lead. Finally, a prescription-prepared ointment was evaluated, which the patient had applied to his feet and lips over the past 3 years.

CONCLUSION

Lead poisoning can be found outside the realm of occupational exposure; therefore, the knowledge of lead poisoning is still important.

Reaction-induced infrared difference spectroscopy for the study of protein reaction mechanisms

This paper reviews state-of-the-art reaction-induced infrared difference spectroscopy of proteins. This technique enables detailed characterization of enzyme function on the level of single bonds of proteins, cofactors, or substrates. The following methods to initiate a reaction in the infrared sample are discussed: (i) light-induced difference spectroscopy, (ii) attenuated total reflection with buffer exchange, (iii) the infrared variant of stopped and continuous flow, (iv) temperature and pressure jump, (v) photolytical release of effector substances from caged compounds, (vi) equilibrium electrochemistry, and (vii) photoreduction. Illustrating applications are given including hot topics from the fields of bioenergetics, protein folding, and molecule--protein interaction.

Cytochrome P450 (P450) isoforms expression, P450 concentration, monooxygenase activities, reactive oxygen species formation, lipid peroxidation, and glutathione content in wild catch carp and tench liver--influence of a two weeks exposure to phenobarbital

Carps, both sexes, 3 years old, weighing about 1 kg, and tenches of both sexes, 6 years old, weight about 250 g, were caught from a Thuringian lake without industrial pollution in November 1995 (fish without food uptake, water temperature at about 10 degrees C) and kept for 2 weeks in basins with clean water and addition of 0, 0.1, 1.0 or 10.0 mg/l phenobarbital-Na (PB). The concentration of PB was controlled during and at the end of the exposure period. The animals were fed pellets, but no food uptake was observed. After 24-48 h in fresh water the fish were sacrificed and the following hepatic parameters were immediately determined biochemically: monooxygenase functions: cytochrome P450 (P450) content, ethylmorphine N-demethylation (EN), ethoxycoumarin O-deethylation (ECOD), ethoxyresorufin O-deethylation (EROD), 7-benzyloxy-4-methyl-coumarin O-debenzylation (BCDB); oxidase function indicators: microsomal Fe2+/NADPH dependent hydrogen peroxide formation (H2O2), microsomal Fe2+/NADPH dependent luminol and lucigenin amplified chemiluminescence (LMCL, LCCL), microsomal Fe2+/NADPH dependent lipid peroxide formation (LPO); oxidative state: lipid peroxidation products (TBARS) and GSH and GSSG. Additionally, the expression of three P450 isoforms, 1A1, 2B and 3A, was assessed immunohistochemically in tissue samples from brain, gill, heart, spleen, liver, gut and ovary of both fish species and in kidney of tenches. PB did not influence body or liver weights, but increased liver P450 concentration in both species by 50-100%, though not significantly. Carp: PB increased both EN and EROD significantly, but not ECOD and BCDB; H2O2 and TBARS were enhanced significantly. LPO, LMCL and LCCL were not significantly influenced. Tench: PB increased all monooxygenase reactions (EN, ECOD, BCDB and EROD), though only significantly ECOD; H2O2 was elevated only after treatment with 0.1 mg/l PB, whereas LPO was decreased (!) after treatment by all three concentrations, though significantly only after 1.0 mg/l PB. LMCL was depressed (not significantly), but LCCL increased 5fold. TBARS were significantly enhanced. P450 1A1 subtype expression was concentration dependently elevated by PB in gill and liver of both fish and in the heart and kidney of tenches, P450 2B and 3A isoforms expression was induced in brain, gill, heart, liver and gut of both fish and in the kidney of tenches. In summary, the increased activities of the monooxygenase reactions tested and the elevated expression of all three P450 isoforms investigated in certain tissues indicate an induction of the P450 families 1, 2 and 3 by PB in fish.

CT and MRI in acute hemorrhagic stroke

We report the case of a woman presenting with an acute onset of hemiplegia. MRI was performed and showed a hyperintense mass on diffusion-weighted imaging, with areas of high signal intensity on T2* imaging and T2/PD imaging. T1-weighted imaging showed a more inhomogeneous lesion with a central isointense part corresponding to the acute clot, as well as a peripheral crescent of hypointense plasma; since another mass lesion could not be acutely excluded, computed tomography was performed immediately afterwards, showing a hyperdense hematoma. The patient was taken to the neurosurgical operating theater, where she underwent decompressive craniotomy and evacuation of the hematoma.

P(3)-[2-(4-hydroxyphenyl)-2-oxo]ethyl ATP for the rapid activation of the Na(+),K(+)-ATPase

P(3)-[2-(4-hydroxyphenyl)-2-oxo]ethyl ATP (pHP-caged ATP) has been investigated for its application as a phototrigger for the rapid activation of electrogenic ion pumps. The yield of ATP after irradiation with a XeCl excimer laser (lambda = 308 nm) was determined at pH 6.0-7.5. For comparison, the photolytic yields of P(3)-[1-(2-nitrophenyl)]ethyl ATP (NPE-caged ATP) and P(3)-[1, 2-diphenyl-2-oxo]ethyl ATP (desyl-caged ATP) were also measured. It was shown that at lambda = 308 nm pHP-caged ATP is superior to the other caged ATP derivatives investigated in terms of yield of ATP after irradiation. Using time-resolved single-wavelength IR spectroscopy, we determined a lower limit of 10(6) s(-1) for the rate constant of release of ATP from pHP-caged ATP at pH 7.0. Like NPE-caged ATP, pHP-caged ATP and desyl-caged ATP bind to the Na(+), K(+)-ATPase and act as competitive inhibitors of ATPase function. Using pHP-caged ATP, we investigated the charge translocation kinetics of the Na(+),K(+)-ATPase at pH 6.2-7.4. The kinetic parameters obtained from the electrical measurements are compared to those obtained with a technique that does not require caged ATP, namely parallel stopped-flow experiments using the voltage-sensitive dye RH421. It is shown that the two techniques yield identical results, provided the inhibitory properties of the caged compound are taken into account. Our results demonstrate that under physiological (pH 7.0) and slightly basic (pH 7.5) or acidic (pH 6. 0) conditions, pHP-caged ATP is a rapid, effective, and biocompatible phototrigger for ATP-driven biological systems.

Influence of subchronic administration of oestrone-3-O-sulphamate on oestrone sulphatase activity in liver, spleen and white blood cells of ovariectomized rats

Inhibition of oestrone sulphatase followed by oestrogen removal from tumour cells may be a new form of endocrine therapy of breast cancer in women. We investigated the inhibitory effect of the subchronic administration of oestrone-3-O-sulphamate (EMATE), a steroid sulphatase inhibitor, to ovariectomized rats, to evaluate this method for testing new nonsteroidal inhibitors. EMATE in DMSO was administered both orally and subcutaneously (s.c.) for 7 days at doses of 0.5 and 2.5 mg/kg. In addition the rats were injected s.c. with 0.5 mg oestrone sulphate/kg 26 and 2 h before decapitation under ether anaesthesia. Oestrone sulphatase activity (ESA) was measured radiometrically using [3H]oestrone sulphate as substrate for desulphuration in white blood cells, liver homogenate, microsomes and spleen homogenate. ESA in liver microsomes was found to be nearly 40 times higher than in white blood cells while in spleen ESA was nearly half of that found in liver homogenates and white blood cells. ESA can be inhibited by EMATE down to 50-1.5% of control activity depending on the dose and administration route. The inhibition was in the order, liver homogenate < spleen < liver microsomes < white blood cells, and was more pronounced after s.c. administration of the inhibitor than after oral administration. Ovariectomy was found to be not necessary for oestrone sulphatase-inhibiting studies. Two sequential s.c. injections of oestrone sulphate enhanced the enzyme activities significantly in liver and white blood cells, but not in spleen. In conclusion, white blood cells and liver microsomes of intact female rats can be used for ESA-inhibiting studies. Sulphate-conjugated oestrone can induce oestrone sulphatase in vivo in liver and white blood cells thereby enhancing oestrogen supply in the peripheral organs.

Silent cerebral ischemia detected by diffusion-weighted MRI after carotid endarterectomy

BACKGROUND AND PURPOSE

Small emboli arising from a friable plaque during carotid endarterectomy (CEA) constitute an important risk of perioperative ischemic complications. To evaluate the incidence and significance of silent cerebral ischemic lesions of embolic origin after CEA, we prospectively examined a series of surgical patients with high-grade carotid stenosis by using diffusion-weighted MRI (DWI). We also tried to correlate postoperative ischemic lesions with the occurrence of sonographic cerebral embolic signals, the presence of plaque ulcerations, and the use of intraoperative shunting.

METHODS

Of a consecutive series of 53 patients undergoing elective CEA for high-grade carotid stenosis, 48 patients with unchanged postoperative neurological status were prospectively studied with DWI of the brain the day before and the day after the operation. The magnetic resonance images were analyzed by 2 neuroradiologists blinded to the clinical result of the operation. Any new hyperintense signal was interpreted as a postoperative ischemic lesion.

RESULTS

Forty-six (95.8%) of 48 patients had unchanged postoperative brain DWI. In 2 patients (4.2%), a new single asymptomatic hyperintense signal was observed on the side of the operation. Both lesions were small and presumably of embolic origin. They were not related to sonographic embolic signals, plaque ulcerations, or intraoperative shunting.

CONCLUSIONS

These results suggest that the incidence of silent ischemic brain lesions of embolic origin after CEA is low and does not correlate with the occurrence of intraoperative sonographic microemboli. They confirm that CEA is a safe procedure that carries a low risk of postoperative cerebral events.

Influence of subchronic administration of catechol estrogens on the formation of reactive oxygen species in rat liver microsomes

Metabolic pathways of estrogens are the formation of catechol estrogens (CE; 2- and 4-hydroxy-estrogens), redox cycling of CE and free radical generation, mediated through cytochrome P450 (P450) oxidase/reductase activity. In previous investigations subchronic administration of estrogens showed prooxidative and antioxidative activities in rat liver microsomes (BARTH et al. 1999). To find out whether or not catechol metabolites are responsible for prooxidative activity, we checked 2- and 4-hydroxy-estradiol (2OH-E2 and 4OH-E2) and the non-catechol metabolite 6alpha-hydroxy-estradiol (6alpha-OH-E2) for formation of reactive oxygen species in liver microsomes of 30-day-old male Wistar rats after 5 days treatment (1, 10 mg/kg b. wt. orally, once a day). The results were compared with those after treatment of the rats with estradiol (E2), estradiol valerate (E2V) and ethinylestradiol (EE2). In liver homogenates glutathione and lipid peroxides were determined, in microsomes NADPH-Fe++-stimulated lipid peroxidation (LPO), H2O2 generation and lucigenin (LUC) and luminol (LUM) amplified chemiluminescence (CL) were investigated. In liver 9000 x g supernatants monooxygenase activities were measured. The two catechol estrogens did not show any antioxidative activity, whereas 6alpha-OH-E2 significantly diminished lipid peroxides in the liver as well as LPO and LUM-CL in liver microsomes. Among estrogens, only EE2 showed antioxidative activity. Both CE inhibited ethoxycoumarin O-deethylation. Peroxidative activity as enhanced LUC-CL was found after 2OH-E2 (1 mg/kg b.wt.) and E2, but 10 times higher doses of both CE did not change LUC-CL. Microsomal H2O2 generation was enhanced by E2, E2V and both CE, not by 6alpha-OH-E2. The lower level of H2O2 enhancement caused by CE in comparison to E2 and E2V together with unchanged LUC-CL after high CE doses did not unequivocally prove the CE to be mainly responsible for the prooxidative activities of E2 and E2V in liver microsomes, at least in 30-day-old male rats. Unchanged GSH in the liver after CE administration supports this hypothesis.

[Results and role of carotid endarterectomy]

BACKGROUND

The indications for carotid endarterectomy have been defined on the basis of several large prospective randomised trials. Today this operation is widely performed as primary and secondary stroke prevention in patients with high grade carotid artery stenosis. Permanent quality control of the surgical results is mandatory to ensure optimal stroke prevention and further reduce perioperative complications.

METHODS

In this retrospective study we analyse the surgical results of 272 consecutive carotid endarterectomies performed in 260 patients with special emphasis on the prevention of intraoperative brain ischaemia. Patients were operated on in general anaesthesia and moderate hypothermia. Before clamping the arteries at the neck, a fast-acting barbiturate or propofol was administered intravenously to obtain burst suppression on the EEG. Transcranial Doppler sonography allowed continuous intraoperative monitoring of brain perfusion and detection of emboli. Intraoperative shunting was performed only when the collateral circulation was insufficient.

RESULTS

The postoperative course was uneventful in 249 endarterectomies (91.5%). The internal carotid artery was sonographically recanalised at hospital discharge and at 6-week follow-up in all 249 cases. Ischaemic cerebral complications were observed in 7 patients (2.6%): minor reversible brain ischaemia in 4 (1.5%), and major brain ischaemia with infarction in 3 (1.1%). Three patients died in the perioperative period, representing a mortality rate of 1.1% in this series. The overall combined stroke and death rate was 3.7%. The combined major stroke and death rate was 2.2%. Various non cerebral complications occurred in 13 patients (4.8%).

CONCLUSIONS

These results confirm that endarterectomy is a safe and efficient treatment for atherosclerotic carotid stenosis at the neck. Very low complication rates can be attained by non-invasive diagnostic methods combined with intraoperative monitoring of cerebral blood flow velocity. New upcoming endovascular therapies such as percutaneous angioplasty and stenting need to be compared with these current surgical results with regard not only to perioperative morbidity and mortality but also patency rate, restenosis, and intracerebral blood flow restoration.

Substrate binding and enzyme function investigated by infrared spectroscopy

Protein conformational changes triggered by molecule binding are increasingly investigated by infrared spectroscopy often using caged compounds. Several examples of molecule-protein recognition studies are given, which focus on nucleotide binding to proteins. The investigation of enzyme mechanisms is illustrated in detail using the Ca(2+)-ATPase of the sarcoplasmic reticulum membrane as an example. It is shown that infrared spectroscopy provides valuable information on general aspects of enzyme function as well as on molecular details of molecule-protein interactions and the mechanism of catalysis.

[Pseudostenocardia due to exposure to "electrosmog"]

HISTORY AND REASON FOR ADMISSION

A 44-year-old man had anginal-like complaints. He was convinced that cardiac problems had been caused by electromagnetic fields.

INVESTIGATIONS

Apart from hypertension and hyperlipidaemia there were no other significant findings. ECG, ergometry Holter-ECG were normal.

EXPERIMENT

We tried to verify with a double-blind provocation test if the patient's complaints had been caused by electromagnetic fields. The patient was exposed to an electric instrument without being aware whether it was switched on or off. He was questioned about his perception of the presence of an electric current.

CONCLUSION

The results of the test showed that there was no causal relation between the patient's angina-like-symptoms and electromagnetic fields. The phenomenon of electrosensitivity was probably caused by psychological mechanisms.

Ace/Fgf8 is required for forebrain commissure formation and patterning of the telencephalon

Fibroblast growth factors (Fgfs) form a large family of secreted signalling proteins that have a wide variety of roles during embryonic development. Within the central nervous system (CNS) Fgf8 is implicated in patterning neural tissue adjacent to the midbrain-hindbrain boundary. However, the roles of Fgfs in CNS tissue rostral to the midbrain are less clear. Here we examine the patterning of the forebrain in zebrafish embryos that lack functional Fgf8/Ace. We find that Ace is required for the development of midline structures in the forebrain. In the absence of Ace activity, midline cells fail to adopt their normal morphology and exhibit altered patterns of gene expression. This disruption to midline tissue leads to severe commissural axon pathway defects, including misprojections from the eye to ectopic ipsilateral and contralateral targets. Ace is also required for the differentiation of the basal telencephalon and several populations of putative telencephalic neurons but not for overall regional patterning of forebrain derivatives. Finally, we show that ace expression co-localises with anterior neural plate cells that have previously been shown to have forebrain patterning activity. Removal of these cells leads to a failure in induction of ace expression indicating that loss of Ace activity may contribute to the phenotypes observed when anterior neural plate cells are ablated. However, as ace mutant neural plate cells still retain at least some inductive activity, then other signals must also be produced by the anterior margin of the neural plate.

Iatrogenic Rupture of a Cerebral Aneurysm on the Feeding Artery of an Arteriovenous Malformation

We present the case of a patient with acute onset of headache who showed a flow-related acutely ruptured aneurysm on the feeding artery of an AVM in the angiogram. Rerupture of the aneurysm occurred during angiography after endovascular treatment with a Guglielmi detachable coil. The possible mechanisms leading to rupture of the aneurysm are discussed.

Fine-structure enhancement--assessment of a simple method to resolve overlapping bands in spectra

A simple mathematical procedure--fine-structure enhancement--has been assessed on its ability to resolve overlapping bands in spectra. Its advantages and limitations have been explored using synthetic and experimental spectra. Fine-structure enhancement involves smoothing the original spectrum, multiplying the smoothed spectrum with a weighting factor and subtracting this spectrum from the original spectrum. As a result, the fine-structure of the original spectrum is enhanced in the processed spectrum and bands that overlap in the original spectrum appear as distinct bands in the processed spectrum. To be resolved by fine-structure enhancement, Lorentzian lines have to be separated by more than their quarter width at half maximum, Gaussian lines by more than their half width at half maximum. A comparison of fine-structure enhancement and Fourier self-deconvolution shows that Fourier self-deconvolution has in theory a higher potential to resolve overlapping bands. However, this depends crucially on the correct choice of the parameters. In practice, when parameters commonly used are chosen for Fourier self-deconvolution, fine-structure enhancement leads to similar results. This is demonstrated at the example of the infrared absorbance spectrum of the protein papain, where the amide I band components could be resolved similarly with both methods. Thus, fine-structure enhancement seems to be a simple alternative to Fourier self-deconvolution that does not require specialised software.

Structural changes of the sarcoplasmic reticulum Ca(2+)-ATPase upon nucleotide binding studied by fourier transform infrared spectroscopy

Changes in the vibrational spectrum of the sarcoplasmic reticulum Ca(2+)-ATPase upon nucleotide binding were recorded in H(2)O and (2)H(2)O at -7 degrees C and pH 7.0. The reaction cycle was triggered by the photochemical release of nucleotides (ATP, ADP, and AMP-PNP) from a biologically inactive precursor (caged ATP, P(3)-1-(2-nitrophenyl) adenosine 5'-triphosphate, and related caged compounds). Infrared absorbance changes due to ATP release and two steps of the Ca(2+)-ATPase reaction cycle, ATP binding and phosphorylation, were followed in real time. Under the conditions used in our experiments, the rate of ATP binding was limited by the rate of ATP release (k(app) congruent with 3 s(-1) in H(2)O and k(app) congruent with 7 s(-1) in (2)H(2)O). Bands in the amide I and II regions of the infrared spectrum show that the conformation of the Ca(2+)-ATPase changes upon nucleotide binding. The observation of bands in the amide I region can be assigned to perturbations of alpha-helical and beta-sheet structures. According to similar band profiles in the nucleotide binding spectra, ATP, AMP-PNP, and ADP induce similar conformational changes. However, subtle differences between ATP and AMP-PNP are observed; these are most likely due to the protonation state of the gamma-phosphate group. Differences between the ATP and ADP binding spectra indicate the significance of the gamma-phosphate group in the interactions between the Ca(2+)-ATPase and the nucleotide. Nucleotide binding affects Asp or Glu residues, and bands characteristic of their protonated side chains are observed at 1716 cm(-1) (H(2)O) and 1706 cm(-1) ((2)H(2)O) and seem to depend on the charge of the phosphate groups. Bands at 1516 cm(-1) (H(2)O) and 1514 cm(-1) ((2)H(2)O) are tentatively assigned to a protonated Tyr residue affected by nucleotide binding. Possible changes in Arg, Trp, and Lys absorption and in the nucleoside are discussed. The spectra are compared with those of nucleotide binding to arginine kinase, creatine kinase, and H-ras P21.

Diffusion-weighted MRI for monitoring neurovascular interventions

Carotid stenting is increasingly considered as treatment for carotid artery disease. A reliable noninvasive method is desirable for assessing the safety of the procedure. Diffusion-weighted MRI (DWI) is sensitive to early brain ischaemia which becoming widely available and might therefore serve this purpose. We prospectively studied 19 patients referred for investigation of carotid artery disease by echo-planar whole-brain DWI before and within 24 h of stenting. The images obtained at a high b value were examined by two independent blinded reviewers for new high-signal areas consistent with ischaemia. We found that 15 patients had no new changes after stenting. One patient showed enlargement of a posterior watershed lesion after the procedure, which correlated with an increase in neurological deficit. Three other patients had presumed small embolic infarcts on DWI; two were asymptomatic and one had weakness at the hand that corresponded to an embolic infarct with a lesion on DWI in the hand notch. There were no false- positive or -negative results on DWI, when compared to clinical findings. DWI is thus a new method that can demonstrate neurologically silent or asymptomatic infants. It can be used to help to assess the safety and efficacy of neurovascular intervention.

Phosphoenzyme conversion of the sarcoplasmic reticulum Ca(2+)-ATPase. Molecular interpretation of infrared difference spectra

Time-resolved Fourier transform infrared difference spectra of the phosphoenzyme conversion and Ca(2+) release reaction (Ca(2)E(1)-P --> E(2)-P) of the sarcoplasmic reticulum Ca(2+)-ATPase were recorded at pH 7 and 1 degrees C in H(2)O and (2)H(2)O. In the amide I spectral region, the spectra indicate backbone conformational changes preserving conformational changes of the preceding phosphorylation step. beta-sheet or turn structures (band at 1685 cm(-1)) and alpha-helical structures (band at 1653 cm(-1)) seem to be involved. Spectra of the model compound EDTA for Ca(2+) chelation indicate the assignment of bands at 1570, 1554, 1411 and 1399 cm(-1) to Ca(2+) chelating Asp and Glu carboxylate groups partially shielded from the aqueous environment. In addition, an E(2)-P band at 1638 cm(-1) has been tentatively assigned to a carboxylate group in a special environment. A Tyr residue seems to be involved in the reaction (band at 1517 cm(-1) in H(2)O and 1515 cm(-1) in (2)H(2)O). A band at 1192 cm(-1) was shown by isotopic replacement in the gamma-phosphate of ATP to originate from the E(2)-P phosphate group. This is a clear indication that the immediate environment of the phosphoenzyme phosphate group changes in the conversion reaction, altering phosphate geometry and/or electron distribution.

Influence of oestrogens on formation of reactive oxygen species in liver microsomes of differently aged male Wistar rats

Metabolic pathways of oestrogens are the formation of catechol oestrogens (CE; 2- and 4-hydroxy-oestrogens), redox cycling of CE and free radical generation, mediated through cytochrome P450 (P450) oxidase/reductase activity. We checked the oestrogens oestradiol (E2), oestradiol valerate (E2V) and ethinyloestradiol (EE2) for formation of reactive oxygen species in vitro and ex vivo in male Wistar rats in dependence on age. In liver microsomes of 10-, 30-, 60- and 270-day-old rats the influence of E2, E2V and EE2 (10(-7)-10(-3) M) on NADPH-Fe(++)-stimulated lipid peroxidation (LPO), H2O2 generation and lucigenin (LUC) and luminol (LUM) amplified chemiluminescence (CL) was investigated. The same parameters, additionally P450 content and monooxygenase activities were measured in liver 9000 x g supernatants after subchronic administration of the oestrogens (1, 10 mg/kg b. wt. orally). The most important results are the strong inhibitory capacities of the oestrogens in vitro on LPO in the order of E2V < E2 < EE2, most pronounced in 10-, 60- and 270-day-old animals. In microsomes of 30-day-old rats with the highest control LPO the antioxidative effect of the oestrogens was lower. Whereas the H2O2 generation was not changed by E2, enhanced by E2V, but diminished by EE2 in all age groups, CL(LUC) and CL(LUM) were inhibited in the order of E2 < E2V < EE2. Also after subchronical treatment of the rats the antioxidative action of the oestrogens was evident, microsomal LPO was inhibited in the order of E2 < E2V < EE2. All oestrogens inhibited ethylmorphine N-demethylation. But enhanced H2O2 generation and increased CL(LUC) also indicate a formation of reactive oxygen species by these oestrogens. Obviously in vitro the antioxidative phenolic structure of the oestrogens dominates, whereas after in vivo administration the dose- and age-dependent biotransformation produces prooxidative in addition to antioxidative structures.

Two males with childhood disintegrative disorder: a prospective 14-year outcome study

A prospective 14-year outcome study of two children meeting DSM-IV criteria for childhood disintegrative disorder is presented. Their ages at first evaluation were 4 years 7 months and 6 years 3 months. Both are now adults and continue to have a severe pervasive developmental disorder, mental retardation, seizure disorder, and are non-verbal. Both require residential care.