Observation of coherence and partial decoherence of quantized spin waves in nanoscaled magnetic ring structures

Experiments and simulations are reported, which demonstrate the influence of partial decoherence of spin-wave modes on the dynamics in small magnetic structures. Microfocus Brillouin light scattering spectroscopy was performed on 15 nm thick Ni81Fe19 rings with diameters from 1 to 3 microm. For the so-called "onion" magnetization state several effects were identified. First, in the pole regions of the rings spin-wave wells are created due to the inhomogeneous internal field leading to spin-wave confinement. Second, in the regions in between, modes are observed which show a well pronounced quantization in radial direction but a transition from partial to full coherency in azimuthal direction as a function of decreasing ring size. In particular for larger rings a continuous frequency variation with position is observed which is well reproduced by spin-wave calculations and micromagnetic simulations.

Lifestyle intervention in individuals with normal versus impaired glucose tolerance

BACKGROUND

Lifestyle intervention is effective in the prevention of type 2 diabetes in individuals with impaired glucose tolerance (IGT). It is currently unknown whether it has beneficial effects on metabolism to a similar extent, in individuals with normal glucose tolerance (NGT) compared to individuals with IGT.

MATERIALS AND METHODS

Data from 181 subjects (133 with NGT and at risk for type 2 diabetes and 48 with IGT) who participated in the Tuebingen Lifestyle Intervention Program with increase in physical activity and decrease in caloric intake were included into this study. Body fat distribution was quantified by whole-body magnetic resonance (MR) tomography and liver fat and intramyocellular fat by (1)H-MR spectroscopy. Insulin sensitivity was estimated from an oral glucose tolerance test (OGTT).

RESULTS

After 9 +/- 2 months of follow-up, the diagnosis of IGT was reversed in 24 out of 48 individuals. Only 14 out of 133 participants with NGT developed IGT. Body weight decreased in both groups by 3% (both P < 0.0001). Two-hour glucose concentrations during an OGTT decreased in individuals with IGT (-14%, P < 0.0001) but not with NGT (+2%, P = 0.66). Insulin sensitivity increased both in individuals with IGT (+9%, P = 0.04) and NGT (+17%, P < 0.0001). Visceral fat (-8%, P = 0.006), liver fat (-28%, P < 0.0001) and intramyocellular fat (-15%, P = 0.006) decreased in participants with IGT. In participants with NGT these changes were significant for visceral fat (-16%, P < 0.0001) and liver fat (-35%, P < 0.0001).

CONCLUSIONS

Moderate weight loss under a lifestyle intervention with reduction in total, visceral and ectopic fat and increase in insulin sensitivity improves glucose tolerance in individuals with IGT but not with NGT. In individuals with NGT, the beneficial effects of a lifestyle intervention on fat distribution and insulin sensitivity possibly prevent future deterioration in glucose tolerance.

Antiferromagnetic interactions in single crystalline Zn1-xCoxO thin films

In a rather contradictory situation regarding magnetic data on Co-doped ZnO, we have succeeded in fabricating high-quality single crystalline Zn(1-x)Co(x)O (x=0.003-0.07) thin films. This gives us the possibility, for the first time, to examine the intrinsic magnetic properties of ZnO:Co at a quantitative level and therefore to address several unsolved problems, the major one being the nature of the Co-Co interaction in the ZnO structure.

Functional anatomy of visuo-spatial working memory during mental rotation is influenced by sex, menstrual cycle, and sex steroid hormones

Recent observations indicate that sex and level of steroid hormones may influence cortical networks associated with specific cognitive functions, in particular visuo-spatial abilities. The present study probed the influence of sex, menstrual cycle, and sex steroid hormones on 3D mental rotation and brain function using 3-T fMRI. Twelve healthy women and 12 men were investigated. Menstrual cycle and hormone levels were assessed. The early follicular and midluteal phase of the menstrual cycle were chosen to examine short-term cyclical changes. Parietal and frontal areas were activated during mental rotation in both sexes. Significant differences between men and women were revealed in both phases of menstrual cycle. In men we observed a significant correlation of activation levels with testosterone levels in the left parietal lobe (BA 40). In women, a cycle-dependent correlation pattern was observed for testosterone: brain activation correlated with this male hormone only during the early follicular phase. In both cycle phases females' brain activation was significantly correlated with estradiol in frontal and parietal areas. Our study provides evidence that fMRI-related activity during performance of cognitive tasks varies across sex and phases of the menstrual cycle. The variation might be partly explained by better task performance in men, but our results indicate that further explanations like basic neuronal or neurovascular effects modulated by steroid hormones must be considered. Both estradiol and testosterone levels may influence fMRI signals of cognitive tasks, which should affect selection of subjects for future fMRI studies.

Gender dependent APP processing in a transgenic mouse model of Alzheimer's disease

Epidemiological studies have reported a higher prevalence and incidence of Alzheimer's disease (AD) in women. The biochemical basis for this gender-disparate susceptibility is unknown. A gender effect on AD-typical plaque pathology has been shown in APP transgenic mouse models of AD. Female mice elicit higher plaque load than male mice. In an effort to analyze gender-dependent APP processing during postnatal development, we examined APP transgenic mice at time points prior to plaque deposition. At 14 weeks of age there was a significant elevation of C99 and Abeta in female mice compared to males. Furthermore we observed a slight decrease of BACE-activity in male mice as well as higher cerebral manganese levels in females. Although the decline in estrogen levels due to menopause in female patients is still discussed to be a risk factor for AD our results implicates that additional factors like modified BACE-activity or metal levels may contribute to the higher prevalence and incidence of AD in females.

A vicious circle: role of oxidative stress, intraneuronal Abeta and Cu in Alzheimer's disease

Recent evidence indicates that both intraneuronal Abeta and Cu are involved in the pathological processes in Alzheimer's disease (AD). This perspective shows a possible interrelation of these factors. AbetaPP, the precursor of Abeta which represents the main constituent of amyloid plaques, is involved in Cu homeostasis in mammals. In vitro observations and in vivo data obtained from AbetaPP mouse models provide strong evidence that AbetaPP and the resulting Abeta overproduction facilitate intracellular Cu to leave the cell. An increased Cu efflux seems to lead to Cu deficiency and, subsequently, reduced SOD-1 activity. The Cu-dependent SOD-1 activity is the main enzyme involved in detoxifying free radicals. Several reports have shown that oxidative stress is an invariable age-dependent feature in the brain of AD patients. Increased oxidative stress leads to an increase in intraneuronal Abeta accumulation, which has been shown to be the main trigger for neuronal loss in transgenic mouse models. Thus, we conclude that bioavailability of Cu is a crucial point for the pathogenesis of AD.

Magnetic anisotropy of Co2+ as signature of intrinsic ferromagnetism in ZnO:Co

We report on the magnetic properties of thoroughly characterized Zn(1-x)Co(x)O epitaxial thin films, with low Co concentration, x = 0.003-0.005. Magnetic and EPR measurements, combined with crystal field theory, reveal that isolated Co2+ ions in ZnO possess a strong single ion anisotropy which leads to an "easy plane" ferromagnetic state when the ferromagnetic Co-Co interaction is considered. We suggest that the peculiarities of the magnetization process of this state can be viewed as a signature of intrinsic ferromagnetism in ZnO:Co materials.

Factors influencing emergency intubation in the pre-hospital setting—a multicentre study in the German Helicopter Emergency Medical Service

BACKGROUND

Definitive airway control by endotracheal intubation (ETI) is standard of care in pre-hospital airway management. However, there are specific factors that may influence and complicate ETI.

METHODS

Prospective, descriptive study at three German Helicopter Emergency Medical Services (HEMS) over a 1-yr period. We examined the success and complication rate for field intubation performed by trauma anaesthetists.

RESULTS

In 342 patients (9.3%) ETI was performed. The overall success rate was 100%; in 87.4% the first attempt was successful, whereas in 11.1% a second and in 1.5% a third ETI attempt was necessary. No patient required a surgical intervention. Limited access to the patient was found upon arrival at the scene in 20.2% of the patients and in 9.6% of the patients at the time of ETI attempt. An orotracheal ETI technique was used in all patients. In the patients in whom only one ETI attempt was necessary for successful intubation, the assessment of ETI conditions was rated 'very good' or 'good' in 94.7%, but in those requiring a second or third ETI attempt this was reduced to 68.6 and 20.0%, respectively. Difficulties encountered during ETI included blood (19.9%), vomit/debris (15.8%) and secretions (13.8%) in the upper airway; anatomical reasons (11.7%), patient position (9.6%) and surrounding conditions (9.1%), making laryngoscopy more difficult.

CONCLUSIONS

Despite various factors increasing the difficulties in managing the airway in the field, definitive airway control by ETI seems to be safe practice.

Insulin-Sensitizing and Cardiovascular Effects of the Sodium-Hydrogen Exchange Inhibitor, Cariporide, in the JCR

The effects of the sodium-hydrogen (Na/H) exchange inhibitor cariporide (HOE642), on insulin sensitivity and vascular function were studied in the JCR:LA-cp rat and the db/db mouse. In the insulin-resistant rat, cariporide reduced fasting insulin levels (42%, P < 0.02) and insulin response in a meal tolerance test (50%, P < 0.01), indicating increased insulin sensitivity. The ACE inhibitor, ramipril, used as a reference agent, reduced the insulin response to the meal, but not fasting levels. The EC50 for acetylcholine-mediated relaxation of phenylephrine-precontracted aortic rings was significantly lower in cariporide-treated rats (P < 0.002), but not in ramipril-treated rats. Flow response of the coronary circulation to bradykinin was significantly greater in both cariporide- and ramipril-treated rats, (3-fold decrease in the EC50, P < 0.05). Cariporide-treated hearts were smaller, slower beating, with greater developed LVP. In the obese db/db mouse, chronic treatment with cariporide obviated vascular hypercontractility and improved endothelial function. Thus, cariporide had beneficial effects on the abnormal insulin metabolism and associated vascular dysfunction in the JCR:LA-cp insulin-resistant rat, which develops advanced cardiovascular disease and ischemic myocardial lesions. It also improved vascular function in a similar mouse model of insulin resistance. These effects were markedly greater than those of ramipril.

[In-vitro comparison of morphology of current microkeratomes for LASIK]

BACKGROUND

We have performed an in-vitro examination of the morphology of flap thickness and stromal bed after LASIK in porcine eyes.

MATERIALS AND METHODS

Freshly enucleated porcine eyes and synthetic eye models were used for cutting flaps with the microkeratomes Hansatome-Excellus (Bausch&Lomb), M2 single use (Moria), Amadeus (AMO), MK-2000 (Nidek) and Carriazo-Pendular (Schwind). The flap thickness of porcine eyes was determined using a non-contact, confocal optical distance measuring device (CHR 150N, Jurca), in the eye models a mechanical thickness measuring device (Käfler) was used. The morphology of the stromal bed was examined by photography, histology, scanning electron microscopy and confocal optical distance measurements.

RESULTS

The optical/mechanical flap thickness measurements showed an average difference compared to the adjusted thickness of - 3/+ 90 microm (Hansatome-Excellus), + 7/+ 100 microm (M2 single use), - 35/+ 40 microm (Amadeus), - 4/+ 80 microm (MK-2000) and + 11/+ 0 microm (Carriazo-Pendular). Histology showed no mechanical damage and smooth, slightly undulating surfaces with all microkeratomes. In the scanning electron microscopic examination, the stromal surface was found to be homogeneous and smooth for all of the microkeratomes. Average roughness of the ablation surface was 0.27 microm (Hansatome-Excellus), 0.23 microm (M2 single use), 0.21 microm (Amadeus), 0.23 microm (MK-2000) and 0.29 microm (Carriazo-Pendular).

CONCLUSION

The stromal bed showed in all cases only a slightly roughness, which seems to be acceptable for the clinical outcome. However, the more critical point is the large variations in flap thickness compared to the intended thickness.

Renal accumulation and clearance of advanced glycation end-products in type 2 diabetic nephropathy: effect of angiotensin-converting enzyme and vasopeptidase inhibition

AIMS/HYPOTHESIS

Renal accumulation of AGEs may contribute to the progression of diabetic nephropathy. We evaluated the effect of ramipril (a pure ACE inhibitor) and AVE7688 (a dual inhibitor of ACE and neutral endopeptidase) on renal accumulation of the advanced glycation end-product (AGE) 3-deoxyglucosone-imidazolone, carboxymethyllysine (CML) and pentosidine, and on clearance of CML in type 2 diabetes.

METHODS

Male Zucker diabetic fatty rats (ZDF, Gmi-fa/fa) rats were treated from age 10 to 37 weeks with ramipril (1 mg.kg(-1).day(-1)), AVE7688 (45 mg.kg(-1).day(-1)) or without drug. Ramipril and AVE7688 reduced albuminuria by 30 and 90%, respectively.

RESULTS

ZDF rats showed increased renal accumulation of the AGE subtypes 3-deoxyglucosone-imidazolone, pentosidine and CML by about 40, 55 and 55%, respectively compared with heterozygous, non-diabetic control animals at the age of 37 weeks. AVE7688 but not ramipril attenuated the renal accumulation of 3-deoxyglucosone-imidazolone, pentosidine and CML and improved CML clearance in ZDF rats. During glycation reactions in vitro, AVE7688 also demonstrated potent chelating activity and inhibited metal-catalysed formation of pentosidine and CML.

CONCLUSIONS/INTERPRETATION

Improved AGE clearance and direct inhibition of AGE formation by chelation may contribute to reduced accumulation of renal AGEs and to the nephroprotective effects of vasopeptidase inhibition in type 2 diabetes.

[Comparative results of keratometry with three different keratometers after LASIK]

BACKGROUND

Postoperative hyperopia is a frequent result of cataract surgery in eyes after previous myopic kerato-refractive surgery. One reason for the underestimation of intraocular lens (IOL) power is the wrong corneal refractive power measurement obtained by keratometers and corneal topography systems after LASIK. The aim of this study was to compare the precision of measurements of three different keratometers after LASIK.

METHOD

We studied 58 eyes of 34 refractive patients aged between 20 and 51 years. The preoperative measurements and the measurements one month after LASIK were performed with the Keratometer (Zeiss), the corneal topograph (EyeSys Technologies) and the IOL-Master (Zeiss). We compared our postoperative measurement results obtained with the three keratometers with the results obtained by using the clinical history method (chm).

RESULTS

The smallest mean deviation was achieved with the IOL-Master (measured mean +/- SD: 38.94 +/- 1.88 D, vs. chm: 38.35 +/- 2.13 D). The Keratometer (Zeiss) showed a larger deviation (measured: 39.12 +/- 1.76 D, chm 38.34 +/- 2.07 D) and the largest deviation was shown with the corneal topograph (measured: 39.84 +/- 1.85 D, chm: 38.86 +/- 2.10 D), which measured in mean one diopter higher than what was obtained utilizing the chm. A positive correlation between corrected myopia and the postoperative difference between the measured and calculated value for each keratometer was found.

CONCLUSION

This study demonstrates that with common keratometers central corneal power is measured too high after LASIK. For IOL calculation in patients after LASIK, the wrongly positive deviation from measured central corneal power has to be taken into account.

Rubeosis iridis als Komplikation bei Zentralarterienverschluss

BACKGROUND

Iris neovascularization (IN) with a secondary angle closure glaucoma is a complication of central retinal artery occlusion (CRAO). Its incidence is greatly underestimated.

MATERIALS AND METHODS

In a retrospective study we analyzed all patients with CRAO seen within 2 years who were treated in our department. We looked especially for the frequency of the occurrence of IN.

RESULTS

In 27 patients with CRAO, 5 developed an IN with a secondary neovascular glaucoma with high intraocular pressure. Thus, the frequency of IN was 18 % in our patients. The IN occurred 2 months to 2 years after the occlusion. Visual acuity in three eyes was between 1/20 and light perception and two eyes had no light perception. In all cases a panretinal laser treatment was performed. Three eyes were additionally treated with a peripheral retinal cryocoagulation and cyclophotocoagulation. In the histories of these patients, diabetes mellitus and arterial hypertension were found.

CONCLUSIONS

In previous studies it has been shown, that ischemia/reperfusion injuries of the retina after CRAO predispose to IN (incidence 3 - 18 %). Although it has been shown that the majority of IN occurs within three months, our data show that IN may occur as a severe complication of CRAO even later. Patients should be followed-up closely (including gonioscopy), to diagnose the occurrence of IN early. Recommended treatment is panretinal laser coagulation or -- in the case of a secondary angle closure glaucoma -- cyclophotocoagulation, respectively.

Role-playing for more realistic technical skills training

Clinical skills are an important and necessary part of clinical competence. Simulation plays an important role in many fields of medical education. Although role-playing is common in communication training, there are no reports about the use of student role-plays in the training of technical clinical skills. This article describes an educational intervention with analysis of pre- and post-intervention self-selected student survey evaluations. After one term of skills training, a thorough evaluation showed that the skills-lab training did not seem very realistic nor was it very demanding for trainees. To create a more realistic training situation and to enhance students' involvement, case studies and role-plays with defined roles for students (i.e. intern, senior consultant) were introduced into half of the sessions. Results of the evaluation in the second term showed that sessions with role-playing were rated significantly higher than sessions without role-playing.

The vasopeptidase inhibitor AVE7688 ameliorates Type 2 diabetic nephropathy

AIM/HYPOTHESIS

Pharmacological inhibition of the renin angiotensin system has proven clinical efficacy in nephropathies of various origins, including diabetic nephropathy. We tested the effects of the dual inhibition of both angiotensin converting enzyme and neutral endopeptidase by the vasopeptidase inhibitor AVE7688 in an animal model of Type 2 diabetic nephropathy.

METHODS

We treated 56 obese Zucker diabetic fatty (ZDF, Gmi-fa/fa) rats aged 34-weeks with either placebo ( n=9) or the vasopeptidase inhibitor AVE7688 in four different doses (each n=9; 3, 10, 30, or 60 mg/kg/d in chow). We used 11 heterozygous (+/fa) rats which received placebo and served as non-diabetic, lean controls. Urinary albumin/creatinine ratio was assessed as a marker of nephropathy at baseline (age 34-weeks) and after 10 weeks of chronic treatment.

RESULTS

All obese animals had established diabetes mellitus that was not influenced by AVE7688 (HbA(1c) >12%, stable in all dose groups). There was massive albuminuria in the homozygous ZDF rats (albumine/creatinine ratio >20 mg/mg vs minimal albuminuria in lean controls) that was decreased by AVE7688 in a dose dependent manner (Placebo 2.0+/-4.4 vs 11.9+/-1.8, 13.4+/-0.7, 13.6+/-2.8, and 19.8+/-2.8 mg/mg in the 3, 10, 30, and 60 mg/kg/d groups, respectively; all treatment groups p<0.05 vs Placebo).

CONCLUSION/INTERPRETATION

AVE7688 ameliorates proteinuria in Zucker diabetic fatty rats with established diabetes mellitus. Vasopeptidase inhibition represents an effective novel therapeutic principle for intervention in Type 2 diabetic nephropathy independent of metabolic control.

Regulation of the human thromboxane A2 receptor gene in human megakaryoblastic MEG-01 cells

Thromboxane A(2) (TXA(2)) is an important mediator for platelet aggregation and blood vessel constriction. TXA(2) receptor (TP receptor) is expressed in different cell types including smooth muscle cells, endothelial cells and platelets. Expression level of TP receptor may modulate the action of TXA(2) on target cells. In megakaryoblastic MEG-01 cells, a cell line representing a model for platelet precursor cells, addition of phorbolester 12-O-tetradecanoylphorbol-13-acetate (TPA) caused an increase in transcriptional activity of TP receptor gene promoter. Within 20 h a rise in expression of TP receptor mRNA and protein was observed. The effect of TPA was concentration-dependent and was blocked by specific inhibitors of protein kinase C. Flow cytometry analysis indicated that the increase in TP receptor expression appeared to be one of the earliest events in the course of TPA-induced maturation of MEG-01 cells. Stimulation of the protein kinase A pathway by incubation with forskolin or IBMX caused a decrease in transcriptional activity. Promoter deletion experiments indicated that the responsive elements for protein kinase A and C are located upstream and downstream, respectively, of -700 bp of the TP receptor gene. These experiments indicate that the expression of the human thromboxane receptor is differently regulated in platelet precursor cells by the protein kinase A and C pathway.

[Diagnosis of colorectal tumors]

With the introduction of multislice CT extensive volumetric data sets can be quickly acquired in high spatial resolution. The high spatial resolution reduces partial volume effects and enables multiplanar reconstructions. Regarding the colorectum this means that the colon can be assessed if the colon is sufficiently cleaned and distended, and that transmural infiltration of colorectal carcinoma and liver metastases can be better detected. T-staging of colon cancer is less important than T-staging of rectal cancer. Based on the higher contrast MRI is superior to CT in T-staging of rectal cancer and in the differentiation between scarring tissue and recurrence of carcinoma.

Pre-nitrification by encapsulated nitrifiers--a possibility for self-sufficient energy operation of domestic WWTPs

The overall energy consumption of domestic wastewater treatment plants (WWTPs) increases with treatment efficiency. Approximately 30 to 45 kWh per people equivalent and year is mostly necessary for advanced nitrogen and phosphorus removal, while the aeration contains the main part of approximately 60%. A new process using encapsulated nitrifiers on gel lens beads is introduced to overcome the high energy consumption of aeration. A more selective nitrification process was found at a nitrification rate of between 50 and 60 mg nitrogen per hour and litre reaction volume corresponding to a hydraulic retention time (HRT) of about 30 to 60 minutes while the soluble Chemical Oxygen Demand (COD) removal could be less than 30% depending on operational conditions of the bio-reactor. The latter enables internal use of wastewater's COD for a post denitrification. For the new process the energy consumption as well as total volume of bio-reactor are much less (approximately 30 to 50% for both) than conventional processes due to the low sludge age for COD and nitrate removal and the avoidance of internal wastewater recycle. Therefore, self-sufficient energy operation of domestic WWTPs operating with advanced treatment efficiency could become possible, if energy recovery by anaerobic sludge digestion is included.

Advanced nitrogen elimination by encapsulated nitrifiers

By introducing a mixed population of nitrifiers encapsulated in gel lens beads a more selective nitrification process was found in treatment of settled sewage in lab scale at a hydraulic retention time (HRT) of about 30 to 60 minutes. The reaction rates for oxidation of soluble chemical oxygen demand (SCOD) were found to vary between 25 to 150 mg/L x h while nitrification takes place around 50 mg nitrogen per hour and litre reaction volume. However, based on this SCOD removal in the nitrification step, a consequent post-denitrification process without nitrate recycle and dosage of external carbon sources has been proven to reach substantial nitrate elimination of up to 20 mg nitrogen per litre at COD/N-ratios of approx. 6 in settled sewage. At such COD/N-ratios, suitable nitrogen elimination seems to be possible, because the bioflocs of settled sewage, produced so far by SCOD oxidation and entrapment of particulate COD, are passing through the nitrification process having a substantial contribution to the denitrification rate additionally to the remaining SCOD.

Zufütterung von Getreide an männliche Kälber aus der Mutterkuhhaltung während der Weideperiode

Abstract. Title of the paper: Supplementation of grain to suckling beef calves during the grazing period A study on 65 beef cow-calf pairs was conducted to investigate the intake of a feed supplementation with grain and its interrelations to performance and behaviourial characteristics of suckling calves, as well as the development of body condition and milk yield of the dam. The intake of grain in the group receiving the supplementation (group B) was on average 2.7 kg/ calf/day during the grazing period. A substantial individual variation of feed intake from 1.8 kg to 7.7 kg grain/calf/day was determined. In this period, the daily gains and the weaning weights of the calves in group B were higher (15.4% resp. 7.4%). The advantage of the calves of the group B could be proven only in the second half of the grazing period. The supplementation of grain caused significantly lower suckling activities and grazing periods per day. Effects of a grain supplementation in the feeding of suckling calves on pasture could not be determined on both the body condition and the milk yield of the cows.

Depletion of mitochondrial DNA in the liver of an infant with neonatal giant cell hepatitis

A boy presented with lactic acidosis, hepatomegaly, hypoglycemia, generalised icterus, and muscle hypotonia in the first weeks of life. At the age of 2 months, neonatal giant cell hepatitis was diagnosed by light microscopy. Electron microscopy of the liver revealed an accumulation of abnormal mitochondria and steatosis. Skeletal muscle was normal on both light and electron microscopy. At the age of 5 months, the patient died of liver failure. Biochemical studies of the respiratory chain enzymes in muscle showed that cytochrome-c oxidase (complex IV) and succinate-cytochrome-c oxidoreductase (complex II + III) activities were (just) below the control range. When related to citrate synthase activity, however, complex IV and complex II + III activities were normal. Complex I activity was within the control range. The content of mitochondrial DNA (mtDNA) was severely reduced in the liver (17% to 18% of control values). Ultracytochemistry and immunocytochemistry of cytochrome-c oxidase demonstrated a mosaic pattern of normal and defective liver cells. In defective cells, a reduced amount of the mtDNA-encoded subunits II-III and the nuclear DNA-encoded subunits Vab was found. Cells of the biliary system were spared. Immunohistochemistry of mtDNA replication factors revealed normal expression of DNA polymerase gamma. The mitochondrial single-stranded binding protein (mtSSB) was absent in some abnormal hepatocytes, whereas the mitochondrial transcription factor A (mtTFA) was deficient in all abnormal hepatocytes. In conclusion, depletion of mtDNA may present as giant cell hepatitis. mtTFA and to a lesser degree mtSSB are reduced in mtDNA depletion of the liver and may, therefore, be of pathogenetic importance. The primary defect, however, is still unknown.

Immunocytochemical localization of mitochondrial single-stranded DNA-binding protein in mitochondria-rich cells of normal and neoplastic human tissue

Mitochondrial single-stranded DNA-binding protein (mtSSB) is necessary for mtDNA replication. So far the protein has been studied mainly in Escherichia coli and in cell cultures of lower mammals. In this investigation, the authors studied the expression of mtSSB in normal and neoplastic human tissue by light and electron immunocytochemistry. mtSSB has been detected in various tissues and particularly in mitochondria-rich tissues such as external eye muscles and parietal cells of the stomach and in mitochondria-rich tumors (oncocytomas) of various origins. Ultraimmunocytochemistry disclosed the specific distribution of immunoreactive mtSSB over the mitochondria. The staining intensity was heterogeneous. Forty-five percent had a labeling index (silver grains/microm2) greater than 1 and less than 3, approximately 20% had an index of 3 or greater, and 15% of mitochondria remained unstained. The mean labeling index was 1.83. Immunolabeling showed a linear correlation with the mitochondrial profile area (r = 0.82). In conclusion, mtSSB is regularly expressed in normal and neoplastic human tissue of different origin, function, and differentiation. The heterogeneous staining pattern most probably reflects the functional heterogeneity of mitochondria.

Nemaline cardiomyopathy in a young adult: an ultraimmunohistochemical study and review of the literature

Heart transplantation was performed in a 26-year-old man who suffered from severe dilatative cardiomyopathy. A nemaline myopathy characterized by the accumulation of Z-line material and the formation of rod-like structures had been diagnosed in the skeletal muscle. Routine light microscopy of the heart disclosed only nonspecific findings. On electron microscopy scattered cardiomyocytes showed formations of rod-like structures and a structural desintegration of contractile filaments near the intercalated disks. Immunocytochemistry at the light and electron microscopical level exhibited an accumulation of alpha-actinin, desmin, and occasionally vinculin in abnormal cardiomyocytes. The rods were specifically stained with alpha-actinin and were less immunoreactive for desmin. No mutations were revealed in the skeletal muscle alpha-actin gene. The results illustrate a complex derangement of the cytoskeletal apparatus in nemaline cardiomyopathy. Nemaline cardiomyopathy may be difficult to diagnose in routine diagnostic procedures. A close correlation between the severity of cardiac dysfunction and the morphological expression of the disease in the heart may not be found. Nemaline cardiomyopathy should be included in the differential diagnosis of dilatative cardiomyopathy and may be diagnosed with certainty by ultrastructural-immunhistochemical investigations.

Correlation between tapping and inserting of pegs in Parkinson's disease

BACKGROUND

Various investigators have developed complex quantitative instrumental procedures for objective assessment of parkinsonian motor impairment, since drawbacks of rating scales are interrater variability, subjective impression, and insensitivity to subtle modifications.

OBJECTIVES

To determine whether performance of inserting of pegs and tapping (i) correlates with each other (ii) differentiates between parkinsonian subjects and healthy controls and (iii) reflects severity of Parkinson's disease (PD).

SUBJECTS AND METHODS

In 157 previously untreated idiopathic parkinsonian patients and healthy controls, we measured (i) the total time taken to insert 25 pegs from a rack into a series of appropriate holes in a Purdue pegboard-like apparatus and (ii) the number of taps on a contact board with a contact pencil for a period of 32 seconds for assessment of fine motor skills.

RESULTS

Results of both tests correlated with each other, differed between parkinsonian subjects and controls and reflected scored severity of PD. Better correlation with intensity of PD was noted with the Purdue pegboard-like task.

CONCLUSION

Both tapping and inserting of pegs represent useful tools for objective evaluation of severity of PD. Peg insertion correlated better with disease severity. Both approaches may be useful in future clinical studies.

[Psychiatric complications of pharmacotherapy--a review]

Various commonly used drugs with somatic indications may give rise to a host of partially serious psychiatric side-effects. This overview details important prescribed drugs of daily use and their psychiatric complications. The problems of elderly patients are particularly considered. Also, polypharmacy will be given special attention.

Reference electrodes based on conducting polymers

Several attempts to produce conducting polymer based all-solid-state reference electrodes are presented. Open circuit potential of conducting polymers is redox sensitive and Donan equilibrium dependent. Therefore, more sophisticated constructions are necessary. Most promising were bilayers composed of conducting polymers with different ion-exchanger properties.

The use of transmigration and spermac stain to evaluate epididymal cat spermatozoa

Epididymal spermatozoa of domestic cats were diluted with TEST medium and frozen. The parameters - estimated percentage of motile spermatozoa, concentration of spermatozoa, cell morphology and transmigration rate (TMR) - were evaluated before freezing and after thawing. Transmigration is a new method to measure the percentage of spermatozoa that consistently move forward, and has not been investigated with cat spermatozoa until now. Estimated percentage of motile spermatozoa averaged 65%, TMR was 76%, concentration of spermatozoa was 30,000 microl(-1) and the incidence of morphologically abnormal spermatozoa averaged 58% before freezing. After thawing, the estimated number of motile spermatozoa declined by 22%, but TMR remained at 76%. The TMR did not correlate with estimated motility but mostly was higher than the latter, which is postulated to be caused by the mobilizing effect of the countercurrent in the transmigration apparature. The estimated percentage of motile cells in the target chamber of the transmigration apparature was improved by using phosphate-buffered saline (PBS) as transmigration medium. Morphology was assessed both after fixation of spermatozoa in Hancock solution and after staining of smears with Spermac. Spermac did not stain all protoplasmic droplets but proved to be more suitable for the routine examination of acrosomal morphology after thawing.