Proliferation and programmed cell death of neuronal precursors in the mushroom bodies of the honeybee

We have studied proliferation and programmed cell death in the brain of the honeybee during metamorphosis. DNA fragmentation detection using the TUNEL method combined with 5-bromodeoxyuridine incorporation experiments reveal that in the mushroom bodies neurogenesis is terminated by extensive apoptosis. Proliferation of mushroom body neuroblasts is active until the fourth day of pupal development, ceasing abruptly within 1 day after the onset of apoptosis in the mushroom body proliferative clusters. Inside the mushroom bodies, apoptosis spreads from the apical ends of proliferative clusters, beneath the brain's surface, toward the basal ones. The distributions of apoptotic cells and those in the S phase of the cell cycle overlap significantly. Electron microscopic analysis gives further evidence that mushroom body neuroblasts themselves undergo programmed cell death. We suggest that programmed cell death may be the main factor controlling the final number of Kenyon cells produced during metamorphosis. The overlap in time and space between proliferation and apoptosis raises the question of whether the neuronal precursors switch to programmed cell death during the progression of the cell cycle, or afterwards.

[Photorefractive keratectomy. Free-running vs. q-switched Er:YAG laser (scanning mode)]

BACKGROUND

Examination of morphology in plane corneal ablation (in vitro) induced by an Er:YAG-laser (2.94 microns) in two modes: free-running (50 microseconds) and q-switched (200 ns).

METHODS

Sequences of different fluences in each mode were applied to freshly enucleated swine eyes. Parameters of free-running mode: fluences 1.21-4.77 J/cm2, frequency 80 Hz, spot size 500 microns FWHM, hexagonal spot shape. Parameters of q-switched mode: fluences 0.79-2.33 J/cm2, frequency 20 Hz, spot size 500 microns FWHM, round spot shape.

RESULTS

Histology showed thermal damage of 10-25 microns in depth caused by the free-running mode compared with 4.5-7.5 microns by the q-switched mode. In both gross photography and scanning electron microscopic examination, the surface was found to be more homogeneous and smoother in the q-switched mode.

CONCLUSIONS

Depending on the different application modes, both laser systems could be used for a defined corneal ablation in photorefractive keratectomy. However, at the moment, results using the Er:YAG laser are not as favorable as with the excimer laser.

[Temporal bone fracture after head trauma causing rhinoliquorrhea and meningitis]

We report our experience in managing a temporal bone fracture after head trauma that had no apparent clinical signs. Recurrent CSF rhinorrhea and meningitis lead to extensive diagnostic procedures. Operative exploration of the temporal bone demonstrated a fracture line along the horizontal part of the carotid artery. The location of the fracture did not cause such typical symptoms as hearing impairment, facial paralysis, vertigo or tinnitus. Only CSF liquorrhea through the Eustachian tube indicated a fracture at the lateral skull base.

Comparison of free-running vs. Q-switched Er:YAG laser photorefractive keratectomy (scanning mode) in swine eyes

PURPOSE

To examine morphology in plane and incisional corneal ablation (in vitro) induced by an Er:YAG laser (2.94 microm) in two modes: free-running and q-switched.

METHODS

Sequences of different fluences in each mode were applied to freshly enucleated pig eyes. Parameters of free-running mode were: pulse length 50 micros, fluences 1.21 to 4.77 J/cm2, frequency 80 Hz, spot size 500 microm FWHM, hexagonal spot shape. Parameters of q-switched mode were: pulse length 200 ns, fluences 0.79 to 2.33 J/cm2, frequency 20 Hz, spot size 500 microm FWHM, round spot shape.

RESULTS

Histology showed thermal damage of 10 to 25 microm in depth caused by the free-running mode compared with 4.5 to 7.5 microm by the q-switched mode. In both gross photography and scanning electron microscopic examination, the surface was more homogeneous and smoother in the q-switched mode.

CONCLUSIONS

Depending on the different application modes, both laser systems could be used for a defined corneal ablation in photorefractive keratectomy. At present, results using the Er:YAG laser are not as favorable as with the excimer laser.

Exhaled nitric oxide in patients with Wegener's granulomatosis

In Wegener's granulomatosis (WG), a pathogenic role of infections, in particular of a chronic colonization of the nasal mucosa with Staphylococcus aureus, has been postulated. Nitric oxide (NO), which is thought to play a role in primary host defence and inflammation, is produced endogenously within the respiratory tract, mainly from the paranasal sinuses. In order to further characterize its role in WG, nasal and pulmonary NO excretion in WG patients in comparison to healthy volunteers was measured. Seventeen patients with WG were included in the study. Five patients had active disease (bloody rhinitis with ulceration and crusting) and immunosuppressive therapy (IST), and 12 were in remission (six with, and six without, IST). S. aureus was found in the swabs of all patients with active WG and in three patients in remission. NO was measured in exhaled gas using a chemiluminescence analyser. The NO excretion rate in nasally sampled gas was significantly reduced (p<0.05) in patients with active WG ((mean+/-SD)102+/-100 nL x min(-1)) compared to healthy controls (299+/-13 nL x min(-1)), and patients in remission (281+/-86 nL x min(-1) with IST, 280+/-133 nL x min(-1) without IST). Pulmonary NO excretion in active or nonactive WG patients did not significantly differ from that of healthy volunteers (48+/-21 nL x min(-1)). These results demonstrate a reduced nasal NO excretion in active Wegener's granulomatosis. This may be caused by destruction and/or functional impairment of sinus epithelium. The reduced NO concentration may well compromise host defence in the upper airways, thus contributing to colonization with Staphylococcus aureus and further promoting Wegener's granulomatosis.

Diversity of desmosomal proteins in regenerating epidermis: immunohistochemical study using a human skin organ culture model

We recently established a skin organ culture model for epithelial healing by creating a central defect in freshly excised human skin specimens and keeping them in culture for up to 7 days, either untreated or with transplantation of allogenic or autologous keratinocytes. In this study the molecular diversity of cell-cell junction proteins in the regenerating epidermis was analysed immunohistochemically using a broad spectrum of monoclonal antibodies against glycoproteins (cadherins) and plaque proteins of desmosomes. At all stages studied the entire set of desmosomal cadherins [desmogleins (Dsg) 1-3 and desmocollins (Dsc) 1-3] was detected, with Dsg3, Dsc2 and Dsc3 being the most prominent. In the disordered neoepithelium at day 3 (after transplantation) some desmosomal cadherins appeared in their respective stratum compartments. In regenerating epidermis on day 7, which exhibited a more ordered stratification and a compact horny layer, stratification-related patterns of desmosomal cadherins were more pronounced. However, some immaturity of the day-7 neoepidermis was reflected by relatively low levels of the maturation-associated Dsgl and Dsc1 and a strong basal layer expression of Dsg2 which is sparse in normal epidermis. Desmosomal plaque proteins showed expression patterns similar to those in normal healthy epidermis. The adherens junction-related E-cadherin was also detected. Dendritic cells (melanocytes, Langerhans cells) were mainly present at the wound margins. In conclusion, this study demonstrated partial but not complete epidermal maturation and junction development during regeneration up to day 7. This model should also be useful in future studies to evaluate the effects of growth hormones to be used in therapeutic trials on chronic leg ulcers.

Quantification of extracellular and intracellular adenosine production: understanding the transmembranous concentration gradient

BACKGROUND

Inhibitors of adenosine membrane transport cause vasodilation and enhance the plasma adenosine concentration. However, it is unclear why the plasma adenosine concentration rises rather than falls when membrane transport is inhibited. We tested the hypothesis that the cytosolic adenosine concentration exceeds the interstitial concentration under well-oxygenated conditions.

METHODS AND RESULTS

In isolated, isovolumically working guinea pig hearts (n=50), the release rate of adenosine and accumulation of S-adenosylhomocysteine (after 20 minutes of 200 micromol/L homocysteine), a measure of the free cytosolic adenosine concentration, were determined in the absence and presence of specific and powerful blockers of adenosine membrane transport (nitrobenzylthioinosine 1 micromol/L), adenosine deaminase (erythro-9-hydroxy-nonyl-adenine 5 micromol/L), and adenosine kinase (iodotubericidine 10 micromol/L). Data analysis with a distributed multicompartment model revealed a total cardiac adenosine production rate of 2294 pmol. min-1. g-1, of which 8% was produced in the extracellular region. Because of a high rate of intracellular metabolism, however, 70.3% of extracellularly produced adenosine was taken up into cellular regions, an effect that was effectively eliminated by membrane transport block. The resulting approximately 2.8-fold increase of the interstitial adenosine concentration evoked near-maximal coronary dilation.

CONCLUSIONS

We rejected the hypothesis that the cytosolic adenosine concentration exceeds the interstitial. Rather, there is significant extracellular production, and the parenchymal cell represents a sink, not a source, for adenosine under well-oxygenated conditions.

Coordination of tRNA nuclear export with processing of tRNA

Eukaryotic tRNAs are synthesized in the nucleus and need to be exported to the cytoplasm where they function in translation. tRNA export is mediated by exportin-t, which binds tRNA directly and with high affinity. tRNAs are initially synthesized as precursor molecules. Maturation to functional tRNA takes place in the nucleus, precedes export, and includes trimming of the 5' and 3' ends, posttranscriptional addition of the 3' CCA end, nucleoside modifications, and in some cases splicing. Here we address the question of how tRNA maturation is coordinated with export and thus how cytoplasmic accumulation of inactive maturation intermediates is avoided. This could, in principle, be achieved by nuclear retention of immature tRNA or by selective export of the fully mature form. We show that exportin-t has a strong preference for tRNA with correctly processed 5' and 3' ends and nucleoside modification. tRNA recognition by exportin-t can thus be considered as a quality control mechanism for these maturation steps prior to tRNA export. Surprisingly however, exportin-t can efficiently bind unspliced tRNA and intron-containing tRNA is exported when the rate of splicing is slow. During characterization of the exportin-t/tRNA interaction we found that exportin-t recognizes features in the tRNA that are conserved between prokaryotic and eukaryotic tRNAs. Our data suggest that correct tRNA shape, the 5' and 3' terminal ends, and the TpsiC loop are critical for exportin-t binding.

Immunohistochemical detection of human mtDNA polymerase gamma and of human mitochondrial transcription factor A in cytochrome-c-oxidase-deficient oxyphil cells of hyperfunctional parathyroids

Immunohistochemical studies were performed in 18 hyperfunctional parathyroids with oxyphil cell aggregates for the detection of cytochrome-c-oxidase (complex IV of the respiratory chain), mitochondrial DNA polymerase gamma and human mitochondrial transcription factor A (h-mtTFA). Seventy-three oxyphil areas exhibiting a defect of cytochrome-c-oxidase were found. The defect involved both the mitochondrially coded subunits II/III and the nuclear derived subunits Vab. There was no loss of mtDNA polymerase gamma or of h-mtTFA in these foci, corresponding to a high content of mtDNA revealed by in situ hybridization. Isolated defects of h-mtTFA were also not found. In contrast, isolated defects of mtDNA polymerase gamma were present in 22 oxyphil foci. These results show that defects of cytochrome-c-oxidase in oxyphil cells are not due to altered expression of h-mtTFA or DNA polymerase gamma, indicating that other nuclear factors involved in the generation of the respiratory chain may be impaired. The low incidence of defects of mtDNA polymerase gamma and the absence of alterations of h-mtTFA and cytochrome-c-oxidase in these foci suggest that defects of mtDNA polymerase gamma are of minor pathogenetic significance.

[Neonatal hearing screening with the Echosensor automated device for otoacoustic emissions. A comparative study]

Following the recommendations of the United States National Institutes of Health Consensus Conference in 1993, otoacoustic emissions (OAE) are now used internationally for hearing screening. The use of recording systems as well as the interpretation of results requires specially trained personnel although measurements are easier to perform than other recording methods available. To date, no objective method for general hearing screening, has been introduced in Germany, for neonates or children at risk, even though it would be desirable to detect and rehabilitate children with congenital hearing loss as early as possible (incidence, 1-6 per 1000). The Echosensor provides the means for carrying out OAE recordings within a short period of time and includes an automatic evaluation of results. Recordings can also be made by trained personnel. As a comparison test, audiologically trained staff recorded otoacoustic emissions in 111 new-born children in order to compare the results of the Echosensor with the results of a conventional OAE measurements device (the ILO88). The aim of this pilot study was to determine the reliability and validity of the recordings in comparison with available standards in brainstem audiometry. Our study showed that the results of the Echosensor corresponded well with the ILO88 results. Consequently, an OAE measuring method is now available is also provides high sensitivity and specificity and is easy to use. Our findings show that the Echosensor can meet the demands of systematic hearing screening in Germany.

Compositionally different desmosomes in the various compartments of the human hair follicle

Hair follicles are complex organs of the skin, in morphological and ontogenic continuity with the epidermis. We have examined the location of desmosomal cadherins and desmosomal plaque proteins in the hair follicle of adult and fetal human scalp skin by immunohistochemistry and have established a localization "map" of the hair follicle. Using antibodies against the plaque proteins desmoplakin I and II, plakoglobin, and plakophilin 1, we have found that these occur in most, if not all hair follicle desmosomes, whereas plakophilin 2 was absent, except in the basal cells of the outer root sheath, where a weak reactivity was found. By contrast, the desmosomal cadherins were mostly differentially synthesized, displaying a complicated map. While desmocollin Dsc3 was detected in all cell types examined, Dsc1 was detected only in the outer root sheath companion cell layer and the inner root sheath, and Dsc2 showed practically a mutually exclusive presence. Desmoglein Dsg2 was observed in basal cells of the outer root sheath as well as in the central cell layers of the subinfundibular outer rood sheath, matrix cells and trichocytes, in partial overlap with the otherwise different immunopositive reactions of Dsg1 and Dsg3. We have also determined when these proteins are synthesized during fetal hair follicle development. The differential molecular composition of desmosomes is discussed in relation to possible functional differences between the individual cell types.

Adenosine is worth trying in patients with paroxysmal supraventricular tachycardia on chronic theophylline medication

Adenosine is widely used to terminate paroxysmal supraventricular tachycardia. However, it is usually considered of no value in patients on theophylline, for methylxanthines completely antagonize the A(1) -receptor mediated negative dromotropic adenosine effect. We report a case of a 69 year old man who had chronic obstructive lung disease and spontaneous pneumothorax. Supraventricular tachycardia with a heart rate of 200 bpm persisted even after a pleural drain was inserted and the lung became fully inflated. Although the patient was on theophylline medication with effective serum plasma levels, adenosine terminated the supraventricular tachycardia after three repeated doses of 3, 6 and 9 mg, respectively. This observation further nourishes previous hypotheses that chronic administration of an A1-receptor antagonist leads to up-regulation of the adenosine receptor number.

[Immunoglobulin transfer in the viable, newborn calf]

Parturitions of 26 dairy-cows were observed and the viability of the newborn calves assessed. Immediately after birth as well as after the first and forth colostrum intake a blood probe was taken from the neonates and investigated for the following parameters: blood gas, blood picture, total-IG, concentrations of IGG1, IGM and IGE, total proteins and albumin. Before each feeding a colostrum sample was assayed for the same parameters with the exception of blood gas, blood picture and albumin. A transferindex (KLOBASA et al., 1994) was calculated to investigate the absorption of TP, IG, IGG1, IGM and IGE. In some of the blood samples there was no IGE detectable, even after colostrum intake. High individual differences were striking and blood concentrations were not related to the milk contents or the time until first feeding. The total proteins were strongly correlated to the serum concentrations of IGG1, but only in samples taken after first colostrum feeding. Vital calves showed the following tendency: colostrum intake of less than 1 l within the first 15 hours after birth and/or colostrum intake with TP-concentrations of 80 I.U./l was partly compensated by increased absorption of TP. 24 hours after birth serum-immunoglobulinconcentrations were 6-12 mg/ml; weight gain was normal and no calf became ill. In 60% of cases the transferindex for IGM was higher than for IGG1 or IGE.

Electrophysiological considerations regarding electrical stimulation of motor cortex and brain stem in humans

OBJECTIVE

To provide information about activation of descending motor pathways in humans, motor evoked potentials were obtained from 16 patients without any sensorimotor deficit, after both cortical and brain stem stimulation.

METHOD

Total anesthesia was achieved in all patients through intravenous administration. Short trains of one to five electrical pulses were delivered separately to the motor cortex and the brain stem. Compound muscle action potentials were recorded from the contralateral upper extremity. Threshold intensity, stimulus polarity, latencies, and effect of increased stimulus intensity on latencies were analyzed.

RESULTS

The threshold intensity was significantly lower when stimulating the brain stem than when stimulating the cortex. A monophasic anodal stimulus was better for cortical stimulation than for brain stem stimulation. Conversely, a monophasic cathodal stimulus was more effective for brain stem stimulation. The rate of unsuccessful stimulations was higher with brain stem stimulation and with increased stimulation intensity. The variability of latencies was so high that a calculation of the conduction velocity of the motor pathways was not possible.

CONCLUSION

The results indicate that cortical surface and brain stem stimulation act on different nervous elements. Because of the condensation of motor pathway fibers at the brain stem level, much less stimulus intensity for eliciting compound muscle action potentials was necessary. On the other hand, the higher rate of unsuccessful brain stem stimulations may be caused by a block of conduction at either the anterior horn cell pool or the neuromuscular junction. Thus, for cortical and for brain stem stimulation, different stimulating parameters seemed to be necessary with the patient under general anesthesia.

The application of a biotin-anti-biotin gold technique providing a significant signal intensification in electron microscopic immunocytochemistry: a comparison with the ultrasmall immunogold silver staining procedure

A three-step biotin-anti-biotin gold-detection system (method A) has been applied for ultraimmunocytochemistry using ultrasmall colloidal gold (0.8 nm) linked to anti-biotin antibodies which were visualized and enhanced by silver reduction. The reactivity for glucagon in human pancreatic islets and for cytochrome-c oxidase in heart mitochondria has been compared to a two-step ultrasmall immunogold technique (method B). For both antigens, method A provided significantly higher labelling indices (P<0.001): the labelling density for cytochrome-c oxidase was 223/microm2 using method A and 78/microm2 using method B. For glucagon, the labelling density was 1455/microm2 with method A and 322/microm2 with method B. The results demonstrate that the silver-intensified biotin-anti-biotin gold-detection system is a valuable immunocytochemical method for signal enhancement. The method utilizes biotinylated antibodies from different species, allowing its broad application at the electron microscopic level.

Nitric oxide induced contractile dysfunction is related to a reduction in myocardial energy generation

OBJECTIVE

It has been suggested that nitric oxide (NO) is involved in the regulation of myocardial function in a variety of diseases such as dilated cardiomyopathy, myocarditis, heart transplant rejection, and septic shock. However, the underlying mechanism of NO mediated reduction of cardiac contractility has not been clearly established so far. Therefore, we studied the effects of authentic NO on left ventricular function and myocardial energy status in the isolated heart.

METHODS

In 43 isolated perfused guinea pig hearts quantitative and kinetic changes in coronary flow (CF), left ventricular developed pressure (LVDP), the cardiac release of adenosine, lactate, cyclic GMP, and norepinephrine were measured during infusion of authentic NO. In parallel, myocardial phosphocreatine (PCr), ATP and the free energy change of ATP-hydrolysis (delta GATP) were measured using 31P nuclear magnetic resonance spectroscopy.

RESULTS

At low concentrations (0.01 to 1.0 mumol/L) NO increased CF only; at higher concentrations (1 to 100 mumols/L) CF remained elevated and LVDP was significantly reduced. Onset and offset of changes in LVDP occurred always within 2 to 5 s after start and cessation of NO infusion. Contractile dysfunction was significantly correlated to a pronounced increase in adenosine formation (> 70-fold), a significant decrease in myocardial PCr (-78%), ATP (-25%) and a decrease in delta G(ATP) from -61.76 kJ/mol to -50.75 kJ/mol. This was paralleled by a significant decrease in myocardial oxygen consumption (-65%) and a tenfold increase in lactate production. Coronary vasodilation (NO: 0.001 to 1.0 mumol/L) significantly correlated with the increase in cGMP release, whereas at negative inotropic concentrations (NO: 10 to 100 mumols/L) a clear quantitative and kinetic dissociation between NO-induced changes in cGMP and LVDP was observed. Contractile dysfunction was not related to cardiac release of norepinephrine.

CONCLUSIONS

In the isolated heart NO can potently depress myocardial energy generation thus being an effective modulator of cardiac contractility. This effect of NO may be of pathophysiological significance in cardiac muscle disorders in vivo.

Diclofenac concentrations in defined tissue layers after topical administration

INTRODUCTION

To date it is unclear whether therapeutic concentrations are attained in target tissues after topical administration of nonsteroidal anti-inflammatory drugs. Therefore this study in healthy volunteers was undertaken to measure diclofenac concentrations attained in defined tissue layers directly underlying the site of topical diclofenac application by in vivo microdialysis.

METHODS

In each experiment two microdialysis probes were inserted, one into a superficial (3.9 +/- 0.3 mm) and one into a deep (9.3 +/- 0.5 mm) tissue layer, in 20 healthy volunteers and calibrated in vivo. The distance between the surface of the skin and the tips of the microdialysis probes was measured by 7.5 MHz ultrasound. Diclofenac was administered topically as a single dose of approximately 300 mg/100 cm2. Concentration versus time profiles in tissue layers were monitored for 5 hours.

RESULTS

Concentration versus time profiles were obtained in 11 of 20 experiments. However, there was no correlation between area under the concentration-time curve (AUC) in a defined layer and the depth of probe insertion. In those experiments where concentration versus time profiles were obtained for both probes mean AUC was 532 +/- 197 microg x min x ml(-1) for superficial layers, and 438 +/- 249 microg x min x ml(-1) for deep layers.

CONCLUSION

We conclude that transdermal penetration of diclofenac, at least after single doses, is not predictable and may strongly be influenced by individual skin properties.

Quantitative signal analysis in pulsed resonant photoacoustics

The pulsed excitation of acoustic resonances was studied by means of a high-Q photoacoustic resonator with different types of microphone. The signal strength of the first radial mode was calculated by the basic theory as well as by a modeling program, which takes into account the acoustic impedances of the resonator, the acoustic filter system, and the influence of the microphone coupling on the photoacoustic cavity. When the calculated signal strength is used, the high-Q system can be calibrated for trace-gas analysis without a certified gas mixture. The theoretical results were compared with measurements and show good agreement for different microphone configurations. From the measured pressure signal (in pascals per joule), the absorption coefficient of ethylene was calculated; it agreed within 10% with literature values. In addition, a Helmholtz configuration with a highly sensitive 1-in. (2.54-cm) microphone was realized. Although the Q factor was reduced, the sensitivity could be increased by the Helmholtz resonator in the case of pulsed experiments. A maximum sensitivity of the coupled system of 341 mV/Pa was achieved.

Impairment of adenosine-induced dilation of forearm resistance arteries in patients with arterial hypertension

BACKGROUND

Adenosine is a potent mediator of arteriolar tone in particular during ischemia, hypoxia, and exercise. Functional disturbance of this dilatory pathway may be highly significant for the pathophysiology and pathogenesis of arterial hypertension.

PATIENTS AND METHODS

Forearm blood flow (FBF) was quantified by venous occlusion plethysmography following intra-arterial infusion of adenosine at increasing doses in 13 patients with arterial hypertension (HT) and 12 age-matched normotensive controls (NT). Hyperemic peak flow was measured following 3 minutes of non-flow ischemia.

RESULTS

FBF at rest was comparable in both groups and was dose-dependently increased by adenosine in both groups. In patients with HT adenosine-induced vasodilation was significantly impaired over the entire dose-response curve compared with NT (6.0 mumol/min: 14.5 +/- 1.0 versus 8.6 +/- 0.9 ml.min-1.100 ml-1 of tissue, p < 0.01). Maximum forearm blood flow during reactive hyperemia was also profoundly impaired in the hypertensive patients (-38%, p < 0.01). In the overall group of normotensive and hypertensive subjects, flow responses to adenosine were i) significantly correlated with peak flow (adenosine 2.0 mumol/min: r = 0.79, p < 0.001), and total flow during reactive hyperemia and ii) inversely related to the magnitude of arterial blood pressure.

CONCLUSIONS

The study reported presents first evidence that adenosine-dependent dilation of forearm resistance arteries is impaired in patients with arterial hypertension. This vascular dysfunction is associated with the impairment of ischemia-induced reactive hyperemia which in turn may contribute to progressive end-organ damage in arterial hypertension.

Mammalian tRNA(Lys)3 and pre-tRNA(Lys)3 variants as primers and inhibitors of viral cDNA synthesis by HIV reverse transcriptase in vitro

We constructed a set of mammalian tRNA(Lys)3-pseudogenes, whose pre-tRNAs are processing-deficient in HeLa extract. The 3'-flanking region was designed partially or completely complementary to the PBS-flanking nucleotides of the U5-region of HIV-1 genomic RNA. We show that only the pre-tRNA with completely hybridized 3'-flanking region is efficiently extended by the HIV-1 reverse transcriptase, whereas the partially complementary pre-tRNA(Lys)3, the 3'-terminal 10 nucleotides of which are not hybridized to the viral template, is unable to prime the cDNA-synthesis.

[Effect of quality markers of ejaculates of beagle dogs after frequent semen collection]

Semen was collected from 4 adult beagle-dogs twice weekly during six months. The libido did not alter and frequent semen collection did not deteriorate the investigated parameters. Because of a bad constitution, the semen quality of one male was not sufficient. The mean volume of the second fraction of the remainder slightly decreased from January until June from 1.2 to 0.5 ml. On the contrary the mean volume of the first and third fraction increased, mainly from April until May from 0.3 to 1.0 (first fraction) and from 1.0 ml to 5.0 ml (third fraction), resp. The average of the sperm number/microliter augmented from month to month from 71.3 to 324.4 x 10(3)/microliter. The transmigration rate reached its maximum in April (52.2%). The monthly average number of the percentage of morphologically abnormal spermatozoa correlated with the corresponding transmigration rate. There were negative, linear relationships between specific morphological abnormalities of spermatozoa and both estimated motility and transmigration rate.

[Coronary vasomotion in coronary heart disease--significance of epicardial and microcirculatory vessels for myocardial perfusion]

The most important function of the coronary vasculature is the effective regulation of coronary blood flow according to the metabolic needs of the myocardium. Under physiological conditions, coronary blood flow is regulated by a balance of vasoconstricting and -dilating components which can be differentiated with regard to the site (macro- vs. microcirculation), compartment (endothelium vs. vascular smooth muscle), and mechanism of action (receptor dependent vs. independent). This balance includes on the one hand the ability of the coronary circulation to maintain a relatively constant blood flow at any given oxygen demand irrespective of perfusion pressure (coronary autoregulation). On the other hand, coronary blood flow can be increased rapidly and effectively several-fold when myocardial oxygen demand increases. Previous investigations have demonstrated that the coronary endothelium plays a key role in the development of arteriosclerotic vascular lesions. In the time course of arteriosclerosis, functional alterations in endothelium dependent vasodilatation alterations are already present before angiographically demonstrable morphologic lesions. In the present manuscript, the diagnostic methods used to assess clinically the coronary macro- and microcirculation with regard to endothelium and smooth muscle dependent vasomotion are reviewed. In addition, present pharmacotherapeutic strategies to improve myocardial perfusion in coronary artery disease are discussed.

Morphological-cytochemical and molecular genetic analyses of mitochondria in isolated human oocytes in the reproductive age

Molecular genetic, cytochemical and morphometric analyses have been performed on isolated oocytes from 41 women (27-39 years of age) in order to detect mutations of mitochondrial DNA (mtDNA), defects of the respiratory chain (ubiquinone-cytochrome-c-oxidoreductase = complex III; cytochrome-c-oxidase = complex IV) and alterations of mitochondrial volume during cellular ageing. Morphometric analyses showed an increase in mitochondrial numerical density with age from the mean values of 7.36 per micron2 and 6.97 per micron3 up to 30 years to 10.74 per micron2 and 11.66 per micron3 in the age group 31-40 years (P < 0.001). Similarly, an increase in the mitochondrial profile area from 0.074 per micron2 in the age group < 30 years to 0.101 per micron2 was noted in the fourth decade. The mitochondrial volume fraction was also significantly increased in the elder age group. Neither point mutations of mtDNA (nucleotide pairs 3243, 8344) nor the common deletion (4977 bp, nucleotide pairs 8482-13460) could be detected. In parallel, ultra- and immunocytochemical studies of the complexes III-IV failed to reveal functional defects. In conclusion there is an age-related increase in the volume fraction of the mitochondria which might reflect subtle changes in the oxidative phosphorylation capacity, but is not linked to mutations of mtDNA or functional defects of the respiratory chain enzymes in mature human oocytes from women of reproductive age.

Left ventricular mass is linked to cardiac noradrenaline in normotensive and hypertensive patients

BACKGROUND

Left ventricular hypertrophy constitutes a powerful independent risk factor for heart failure, sudden death and ventricular dysrhythmia. Experimental data suggest that, apart from increased cardiac work load, noradrenaline may be one of the factors triggering myocardial hypertrophy.

OBJECTIVE

To test the hypothesis that the extent of left ventricular hypertrophy is coupled to cardiac noradrenaline independently from the magnitude of arterial blood pressure.

PATIENTS AND METHODS

Following exclusion of coronary artery disease by cardiac catheterization, cardiac noradrenaline release was measured in relation to left ventricular mass in 25 patients with arterial hypertension (HT), of whom five had left ventricular hypertrophy (HT + LVH) and 20 had normal left ventricular mass (HT - LVH), seven normotensive patients with hypertrophic cardiomyopathy (HCM) and a normotensive control group (n = 7). Noradrenaline was measured in arterial and coronary venous plasma using high-performance liquid chromatography. Coronary blood flow was quantified using the gas chromatographic argon method. Indices of left ventricular mass were calculated from the end-diastolic thicknesses of the interventricular septum and the posterior wall determined by echocardiography.

RESULTS

The coronary venous plasma concentration of noradrenaline was significantly higher in HT - LVH, HT + LVH and HCM than it was in normotensives. Whereas in normotensives there was a net uptake of noradrenaline (17 +/- 10 pmol/min) across the coronary circulation, a net release of noradrenaline was observed in HT - LVH (69 +/- 26 pmol/min), in HT + LVH (121 +/- 55 pmol/min) and in HCM (341 +/- 96 pmol/min). In a multivariate linear regression analysis model, left ventricular mass correlated significantly with the net noradrenaline release rate (r = 0.64, P < 0.001), whereas arterial blood pressure as an additional independent variable did not correlate with left ventricular mass.

CONCLUSION

The present data demonstrate that an increased left ventricular mass in normotensive and in hypertensive patients is closely coupled to an increased cardiac sympathetic activity, supporting the need for additional studies to determine whether adjunctive sympatholytic therapy is beneficial in patients with left ventricular hypertrophy and increased cardiac noradrenaline release.

Patterns of desmocollin synthesis in human epithelia: immunolocalization of desmocollins 1 and 3 in special epithelia and in cultured cells

Murine monoclonal antibodies (mAbs) which specifically react, in immunoblot and immunolocalization experiments, with the human desmosomal cadherins, desmocollins Dsc1 (mAb Dsc1-U100) and Dsc3 (mAb Dsc3-U114), have allowed to study systematically the synthesis of these proteins in tissues and cultured cells. Application of these mAbs in immunofluorescence microscopy on human skin has shown the presence of Dsc1 in the suprabasal layers of interfollicular epidermis and a specific cell layer of the hair follicle root sheath, whereas Dsc3 has been identified in all living epidermal layers as well as in glandular ducts and in basal matrix cells and the outer root sheath of hair follicles. Dsc3, but not Dsc1, it also present in desmosomes of the basal as well as suprabasal cell layers of other stratified epithelia such as vagina, tongue and esophagus as well as in cells of the basal layer of bladder urothelium and the complex epithelium of trachea. All the diverse one-layered ("simple") epithelia examined were as negative for both, Dsc1 and Dsc3, as were the non-epithelial desmosomes of the intercalated disks of the myocardium. A special situation has been discovered in the thymus. Here the usually single-layered cells of the thymic reticular epithelium are connected by Dsc3-possessing desmosomes, as they also contain typical (type I) hemidesmosomes, whereas Dsc1 is only detected in the "Hassall bodies", spheroidal formations of densely packed reticulum-derived cells which also produce cytokeratins 1 and 10, indicative of suprabasal epidermal differentiation. In cell cultures most, probably all, desmosomes of diverse cell lines derived from stratified squamous epithelia or squamous cell carcinomas, including primary keratinocytes, HaCaT keratinocytes and A-431 carcinoma cells, contain Dsc3. By contrast, Dsc1 has only been detected in local piles of keratinocytes that appear to be in the process of suprabasal differentiation. The antibodies have also allowed to demonstrate that desmosomes of cell lines can contain more than one desmocollin isoform. The observations made by immunofluorescence microscopy are compared with results obtained by in situ hybridization of mRNAs, and the potential value of these mAbs in histology and pathology is discussed.

Symplekin, a novel type of tight junction plaque protein

Using a monoclonal antibody we have identified and cDNA-cloned a novel type of protein localized, by light and electron microscopy, to the plaque associated with the cytoplasmic face of the tight junction-containing zone (zonula occludens) of polar epithelial cells and of Sertoli cells of testis, but absent from the junctions of vascular endothelia. The approximately 3.7-kb mRNA encodes a polypeptide of 1142 amino acids (calculated molecular weight 126.5 kD, pI 6.25), for which the name "symplekin" (from Greek sigma upsilon mu pi lambda epsilon kappa epsilon iota, nu, to tie together, to weave, to be intertwined) is proposed. However, both the mRNA and the protein can also be detected in a wide range of cell types that do not form tight junctions or are even completely devoid of any stable cell contacts. Careful analyses have revealed that the protein occurs in all these diverse cells in the nucleoplasm, and only in those cells forming tight junctions is it recruited, partly but specifically, to the plaque structure of the zonula occludens. We discuss symplekin as a representative of a group of dual residence proteins which occur and probably function in the nucleus as well as in the plaques exclusive for either tight junctions, adherens junctions, or desmosomes.

[Modification of the quality indicators of the ejaculate of beagle dogs due to frequent collections over time]

Ejaculates from five adult beagle dogs were investigated for changes of spermatologic parameters. Semen was collected daily during 12 weeks. The parameters volume, sperm count, and transmigration rate (TMR) increased during the first three to five weeks and decreased in the middle of the experiment. The percentage of morphologically abnormal spermatozoa just exceeded 20% from the fifth to the seventh week and in the tenth week, respectively. Either the results remained on a low level (volume), or they returned to normal from the tenth week on (morphology, TMR, sperm count). Semen quality diminished after five weeks. It is concluded, that daily semen collections during more than five weeks can cause decreased libido, aspermia, and impairment of the conception rates.

Somatosensory evoked potential phase reversal and direct motor cortex stimulation during surgery in and around the central region

In 99 patients with mass lesions in and around the central region, the central sulcus was intraoperatively localized with the use of somatosensory evoked potential (SEP) phase reversal. In 33 of these patients, the motor cortex was directly stimulated and electromyographic responses were recorded from the forearm flexor, thenar, and hypothenar muscles. An additional 25 patients, with subcortical lesions or lesions directly located at the pyramidal tract, were continuously monitored during surgery by motor evoked potentials (MEPs). An exact determination of the central sulcus and tumor localization was possible in all patients; a phase reversal was obtained in 90.8% of the patients, and localization was possible as a result of anatomic structures and the loss of N20 or P20 of SEPs in the other 9.2%. MEPs were obtained in 32 of 33 patients and also in all 25 patients who underwent MEP monitoring at the beginning of tumor removal. From this study, it can be concluded that the combination of SEP phase reversal and modified electrical cortex stimulation is compatible with general anesthesia, although anesthesia was not systematically controlled according to a protocol. Although this study demonstrates that the combined SEP/MEP technique was feasible, it is not yet possible to demonstrate benefit in improving the outcome of patients. Concerning the safety of stimulation, the exact localization of the central sulcus by the noninvasive SEP method, compared with direct electrical stimulation, offered more safety for the patient. The modified technique of direct motor cortex stimulation needed much less charge density than did the common technique. The recording of electromyographic responses instead of movements made objective documentation possible, and the analysis of amplitudes and latencies will supply quantitative information about the motor system.

Immunological identification and characterization of the desmosomal cadherin Dsg2 in coupled and uncoupled epithelial cells and in human tissues

Cells of epithelia, but also of certain other tissues such as myocardium and the dendritic reticulum of lymph node follicles, are interconnected by numerous intercellular junctions termed desmosomes. These are characterized by a set of transmembrane glycoproteins, i.e. the desmosomal cadherins, desmoglein(s) and desmocollin(s). Using cDNA-derived hybridization probes, we have previously shown that different desmogleins exist (Dsg1-3) and that only one Dsg isoform, Dsg2, is found in diverse kinds of tissues, tumors and cultured cell lines whereas the synthesis of Dsg1 and Dsg3 is much more restricted, primarily to stratified epithelia [51]. We now report immunocytochemical results obtained with a series of monoclonal and polyclonal antibodies specific for either the aminoterminal extracellular portion or the carboxyterminal cytoplasmic segment of Dsg2. These antibodies detect Dsg2 in all tissues possessing desmosomes, including human stratified and single-layered polar epithelia, as well as non-epithelial tissues such as myocardium and lymph node follices. They also react with the desmosomes of carcinomas and of diverse cultured epithelium-derived cell lines. Moreover, antibodies specific for extracellular domain regions of Dsg2 react with the "half-desmosomes" present on the surfaces of uncoupled intact epithelial cells. Remarkably, in stratified squamous epithelia the Dsg2-reaction is not homogeneous, as this glycoprotein is detected only in the basal cell layer and appears to be absent from suprabasal strata. The potential value of Dsg2-specific antibodies in histology and in tumor diagnosis as well as in studies of the mechanisms desmosomal cell coupling is discussed.

Defects of the respiratory chain in various tissues of old monkeys: a cytochemical-immunocytochemical study

The aim of the present study was to evaluate if defects of the respiratory chain known to occur in humans, also exist in lower primates. Cytochemical-immunocytochemical studies of the respiratory chain enzymes in five monkeys (10-25 years of age) showed defects of ubiquinone cytochrome-c-oxidoreductase (complex III), of cytochrome-c-oxidase (complex IV) and of ATP-synthase (complex V) in the limb muscles, diaphragm, heart muscle and extraocular muscles of three old animals (about 25 years) and also in the heart muscle of two younger animals (10 and 15 years). Characteristically, the defects were randomly distributed and there was no loss of succinate-dehydrogenase (complex II) in the fibres. Ultracytochemistry-immunocytochemistry of complex IV disclosed that in an involved fibre segment all the mitochondria exhibited the defect. The highest number of defects was observed in the extraocular muscle (up to 340/cm2) while the lowest defect density was present in the limb muscles (2-5/cm2). Defects of complex IV occurred two to three times more often than defects of complex III and besides isolated defects of complex III and IV, combined defects of both complexes were also observed. Defects of complex V occurred exclusively in combination and were rarely seen. Using subunit specific antisera against complex IV, it could be demonstrated at light and electron microscopic level that loss of activity of cytochrome-c-oxidase was associated with a loss both of mitochondrially and nuclearly coded subunits of the enzyme. In summary, aging in lower primates and humans is characterised by a highly similar defect expression of the respiratory chain enzymes, with intercellular and interorgan differences of the aging process, underlining the universal nature of the involved pathogenetic mechanisms.

Characterisation of left ventricular relaxation in the isolated guinea pig heart

The time constant of left ventricular pressure fall, tau, has frequently been used as a measure of myocardial relaxation in the blood-perfused, ejecting heart. The aim of the present study was to characterise tau in relation to beta-adrenergic activation, coronary perfusion pressure and flow as well as cardiac oxygen supply and demand in the isolated, isovolumically beating heart. Therefore, tau was analysed from digitised left ventricular pressure data in a total of 23 guinea pig hearts perfused with saline at constant pressure (60 cmH2O). The coronary venous adenosine concentration ([ADO]) served as an index of myocardial oxygenation. Isoprenaline (0.4-3.2 nmol l-1) decreased and propranolol (3-9 mumol l-1) increased tau dose-dependently (linear regression tau vs lg([isoprenaline]), r = 0.74; tau vs. lg([propranolol]), r = 0.66, both P < 0.05). During graded reductions in cardiac oxygen supply from 96.1 +/- 12.6 (SEM) to 44.4 +/- 4.4 microliters min-1 g-1, tau was prolonged from 61.5 +/- 12.7 to 109.9 +/- 22.6 ms while left ventricular developed pressure (LVDP) decreased from 90.7 +/- 7.2 to 40.7 +/- 5.1 mmHg. In parallel, [ADO] increased from 23.7 +/- 9.1 to 58.0 +/- 19.1 pmol ml-1 (P < 0.05). Increasing oxygen supply to 165.4 +/- 32.4 microliters min-1 g-1 augmented LVDP to 102.7 +/- 7.3 mmHg but did not change tau or [ADO]. There was a dual response of tau to changes in cardiac oxygen supply or demand. As long as oxygen supply and demand matched, tau remained constant. However, when the oxygen supply was less than 100 microliters min-1 g-1, left ventricular relaxation was prolonged in parallel to the reduction in oxygen supply. In addition, a close relationship was observed between [ADO] as an indicator of myocardial oxygenation and tau (Spearman correlation, r = 0.99, P < 0.005). We conclude that the time constant of left ventricular pressure fall, tau, sensitively reflects myocardial relaxation in the isolated, isovolumically beating guinea pig heart. Moreover, in this model left ventricular relaxation is not influenced by alterations in coronary perfusion pressure or flow as long as cardiac oxygen demand is matched by an adequate supply. Rather relaxation is strictly coupled to myocardial oxygenation as reflected by coronary venous adenosine concentrations.

Continual assembly of half-desmosomal structures in the absence of cell contacts and their frustrated endocytosis: a coordinated Sisyphus cycle

It is widely assumed that the coordinate assembly of desmosomal cadherins and plaque proteins into desmosome-typical plaque-coated membrane domains, capable of anchoring intermediate-sized filaments (IF), requires cell-to-cell contacts and a critical extracellular Ca2+ concentration. To test this hypothesis we studied several cell lines grown for years in media with less than 0.1 mM Ca2+ to steady-state low Ca2+ medium (LCM) conditions, particularly the human keratinocyte line HaCaT devoid of any junctional cell contact (HaCaT-L cells). Using immunolocalization and vesicle fractionation techniques, we found that the transmembrane glycoprotein, desmoglein (Dsg), colocalized with the plaque proteins, desmoplakin and plakoglobin. The sites of coassembly of desmosomal molecules in HaCaT-L cells as well as in HaCaT cells directly brought into LCM were identified as asymmetric plaque-coated plasma membrane domains (half-desmosomes) or as special plaque-associated cytoplasmic vesicles, most of which had formed endocytotically. The surface exposure of Dsg in these half-desmosomes was demonstrated by the binding, in vivo, of antibodies specific for an extracellular Dsg segment which also could cross-bridge them into symmetric quasi-desmosomes. Otherwise, these half-desmosomes were shown in LCM to be taken up endocytotically. Half-desmosomal assemblies were also seen in uncoupled cells in normal Ca2+ medium. We conclude that, in the absence of intercellular contacts, assembly of desmosomal proteins at the cell surface takes place, resulting in transient half-desmosomes which then, in LCM and without a stable partner connection to the adjacent cell, can be endocytotically resumed. This frustrated cycle of synthesis and assembly maintains an ensemble of molecules characteristic of epithelial differentiation and the potential to form desmosomes, even when the final junctional structure cannot be formed. We propose that these half-desmosomal structures are general cell structures of epithelial and other desmosome-forming cells.

Staurosporine inhibits the effects of leukotrienes C4 and D4 in isolated guinea pig heart and trachea

Isolated hearts from guinea pigs were perfused at 37 degrees C with Tyrode's solution according to the technique of Langendorff. Coronary flow, left ventricular pressure amplitude and heart rate were measured. Bolus injection of 30 ng leukotriene C4 caused a long-lasting decrease in coronary flow and left ventricular pressure amplitude while heart rate was not affected. A similar but shorter lasting effect was induced by 100 ng leukotriene D4. The effects of the leukotrienes were completely blocked by 1 microM staurosporine. Staurosporine at concentrations of 100 and 10 nM, in contrast to 1 microM, influenced basic cardiac function slightly or not at all, but antagonized the effects of 30 ng leukotriene C4. In isolated tracheal muscle preparations, leukotriene C4 and D4 induced concentration-dependent contractures. Staurosporine at concentrations of 25-100 nM antagonized the effects of leukotriene C4 and D4 in a noncompetitive manner with inhibitor constants of 47.6 and 75.9 nM, respectively. The results indicate that staurosporine is a potent noncompetitive antagonist of the effects of leukotriene C4 and D4 in smooth muscle.

Intracoronary magnesium is not protective against acute reperfusion injury in the regional ischaemic-reperfused dog heart

Intravenous magnesium lowers mortality in patients with suspected myocardial infarction. We tested the hypothesis that the protective effect may be due to a direct, local influence of magnesium on myocardial reperfusion injury in a dog model of ischaemia/reperfusion. Ten anaesthetized open chest dogs underwent 1 h of left anterior descending artery (LAD) occlusion and 6 h of reperfusion. The animals received intracoronary (i.c.) magnesium aspartate (Mg, n = 5) or vehicle infusion (n = 5) for the first hour of reperfusion. Mg infusion was adapted to actual LAD flow (ultrasonic flow probe) to increase regional plasma concentration by 4 mmol L-1. Regional myocardial function was measured as percent systolic wall thickening (sWTh, sonomicrometry). Intracoronary Mg increased LAD flow during application (at 15 min reperfusion; Mg, 194 +/- 44 (mean +/- SD); control, 116 +/- 41 mL min-1 100 g-1, P < 0.01). sWTh decreased during coronary occlusion from 14.3 +/- 7.1% to -4.7 +/- 2.7% in the control group and from 14.8 +/- 2.5% to -4.1 +/- 3.1% in the Mg group. Throughout the reperfusion period wall function remained depressed in both groups to a similar degree (control, -3.5 +/- 1.8%; Mg, -3.0 +/- 1.9% at 6 h reperfusion). Global haemodynamics were not different. Infarct size after 6 h reperfusion (TTC staining) was similar in both groups (Mg, 20.6 +/- 5.0; control, 24.4 +/- 8.7% of area at risk). Regional magnesium application (i.c.) to post-ischaemic reperfused myocardium had no influence on infarct size or post-ischaemic regional wall function in this model.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensory neuron development revealed by taurine immunocytochemistry in the honeybee

The formation of ommatidia in the compound eyes and sensilla on the antennae of the honeybee was followed and the development of their sensory neurons was traced using an antiserum against taurine as a marker. Taurine-like immunoreactivity (Tau-IR) is expressed in sensory neurons of several modalities, namely visual, olfactory, gustatory, and mechanosensory. Staining intensity is very high in the larva and in the first half of the pupal stage and gradually decreases towards the end of metamorphosis. In the photoreceptor cells of the compound eyes, Tau-IR can be detected from the fifth larval instar onwards, prior to differentiation of other components of the ommatidium. Already in the midstage larvae, when the antennal primordia of the adult still lie within the peripodial cavity, a few presumably mechanosensory neurons are labelled in the pedicellus of the developing antenna. The majority of the antennal sensory neurons which are located on the flagellum start to exhibit Tau-IR upon pupation, long before any cuticular specializations such as sensory hairs or plates are detectable. All known types of antennal sensilla were identified and it could be shown that all of them are innervated by Tau-IR sensory neurons. Thus, taurine immunocytochemistry can be applied as a useful label for developing sensory neurons. Functional implications of taurine during development are discussed.

The widespread human desmocollin Dsc2 and tissue-specific patterns of synthesis of various desmocollin subtypes

By comparison of the cDNA-derived amino acid sequences and the cell type-specific patterns of synthesis we have identified desmocollin Dsc2 as the most widespread, perhaps ubiquitous desmocollin subtype. Using Northern blot analyses and ribonuclease protection assays we have found an approximately 5.6 kb mRNA encoding Dsc2 in all the diverse human tissues, tumors and cell lines examined that are known to possess desmosomes, i.e. not only epithelial cells but also myocardiac cells and lymph nodes. By contrast, desmocollin subtypes Dsc1 and Dsc3 have been detected only in certain stratified squamous epithelia, with the most conspicuous restriction of Dsc1 to epidermis and--remarkably, but unexplained--lymph nodes, and in certain carcinomas and cell lines derived therefrom. We have also determined that both Dsc2 mRNA splice forms, the one encoding the larger polypeptide a and the one coding for the shorter Dsc2b, occur in all the diverse tissues and cell lines examined. We also show that certain cells such as the epidermal keratinocyte line HaCaT and the vulvar carcinoma-derived line A-431 continually synthesize more than one Dsc subtype. The cell type-specific patterns of synthesis of the various Dsg and Dsc subtypes are discussed in relation to tissue development during embryogenesis and to malignant transformations, and the utilization of reagents for the specific Dsg and Dsc subtypes in tumor diagnosis is proposed.

Desmosomes and cytoskeletal architecture in epithelial differentiation: cell type-specific plaque components and intermediate filament anchorage

Among the diverse kinds of intercellular, plaque-bearing, cadherin-containing junctions, desmosomes (maculae adhaerentes) represent a major type characterized by the presence of specific transmembrane glycoproteins, i.e. desmosomal cadherins of the desmoglein and desmocollin categories, and the cytoplasmic plaque proteins, desmoplakin I and plakoglobin. Recent studies, however, have shown that the composition of desmosomes is not identical in the various normal and tumorous desmosome-forming tissues and cell cultures, including diverse forms of epithelia and carcinomas, meningothelia and meningiomas, myocardium and the lymph node follicle reticulum. Desmosomes can differ in their specific complement of desmogleins, Dsg1-3, and desmocollins, Dsc1a-3b, as well as in the additional presence and in their relative amounts of certain accessory plaque proteins such as desmoplakin II and plakophilin 1, a basic member of the larger plakoglobin family of proteins ("band 6 protein"). Assembly and function of desmosomes are effected by the interaction of the specific complement of desmosomal cadherins with certain cytoplasmic proteins. In particular, the cytoplasmic portions ("tails") of the desmosomal cadherins contain certain domains and amino acid sequence motifs, identified by mutagenesis and transfection assays, that are essential elements in desmosome formation, notably the assembly of plaque proteins, and in the site-specific anchorage of intermediate-sized filaments (IFs) of the cytoskeleton, thereby contributing to the specific intracellular as well as supracellular, i.e. tissue, architecture.

Cell type-specific desmosomal plaque proteins of the plakoglobin family: plakophilin 1 (band 6 protein)

Desmosomes represent a special type of the plaque-bearing adhering junctions, characteristic of certain pathways of cell differentiation, which compositionally are not identical in the various kinds of desmosome-forming cells. While all desmosomes contain the cytoplasmic plaque proteins desmoplakin I and plakoglobin, they can vary in their specific complement of desmosomal cadherins and by the presence of additional plaque proteins. We have raised monoclonal antibodies recognizing one such 'accessory' plaque protein, the cytokeratin-binding, basic protein plakophilin 1, originally introduced as 'band 6 protein' or 'polypeptide D6', which is an abundant desmosomal component in certain epithelia. Using such antibodies, we have isolated cDNA clones encoding the bovine and the human protein and determined their complete amino acid sequences. The mRNAs, which on Northern blot tests appear as two bands corresponding to approximately 4 and 2.4 kb (bovine) or 5 and 2.6 kb (human), code for 727 amino acids (calculated mol. wt. 80,180; IEP 9.25) in bovine and 726 amino acids (mol. wt. 80,496; IEP 9.34) in human plakophilin. Sequence analyses have revealed the presence of 9.2 repeated units of the arm-motif sequence, confirming our previous conclusion that this protein is a member of a larger family of proteins including, inter alia, several membrane-associated plaque proteins such as vertebrate plakoglobin and beta-catenin as well as the product of the armadillo gene of Drosophila. The plakophilin antibodies and cDNA probes have also allowed us to examine its synthesis in various tissues and cell cultures. While we confirm the occurrence of the protein in cytoskeletal fractions from various stratified squamous, complex, glandular duct and bladder epithelia, where it can be localized to desmosomes, we have, surprisingly, also identified the protein, although at lower amounts, in cytoskeletal fractions from several cultured cell lines in which the protein has not been consistently localized to desmosomes by immunofluorescence microscopy. Examples include cultured cells derived from certain simple epithelia such as the kidney-derived line MDBK and cultured calf lens cells. We have also found that, in all plakophilin 1-positive cells examined, a pool of diffusible ('soluble') cytoplasmic plakophilin exists, including cell lines such as human mammary carcinoma MCF-7 cells in which this soluble plakophilin seems to be the only detectable form. In addition, we have identified some soluble proteins conspicuously cross-reacting with plakophilin 1. Possible functions of plakophilin and its potential value as a marker for specific states of cell differentiation are discussed, particularly with respect to tumor diagnosis.

Left stellate ganglion block impairs left ventricular function

Stellate ganglion block (SGB) is an established procedure for the diagnosis and treatment of chronic pain. SGB results in an acute sympathetic denervation of a part of the left ventricular (LV) wall innervated by the blocked ganglion, which may impair regional contractility. The resulting imbalance of myocardial contractility in different LV regions may affect LV function adversely by increasing LV asynchrony. Seven anesthetized open chest dogs were instrumented for measurement of aortic and LV pressure (tip manometers), cardiac output (CO, thermodilution), and regional LV wall thickness (WT, sonomicrometry) in the anteroapical (predominantly innervated by the right stellate ganglion) and posterobasal wall (left stellate ganglion). The contractility of both regions was assessed using the relationship between preload recruitable stroke work and end-diastolic WT relationship (MW). The timing of regional myocardial wall motion was evaluated by means of the phase of the first harmonic of the Fourier transform of the WT signals, LV asynchrony by the phase difference (PD) between both regions, and LV diastolic function by the time constant of isovolumic relaxation (tau). Measurements were performed before and after left SGB (LSGB). Mean arterial pressure was 105 +/- 25 (mean +/- SD) before and 97 +/- 10 mm Hg after LSGB (not significant). CO remained unchanged (3.09 +/- 1.03 vs 2.93 +/- 1.07 L/min). LSGB significantly reduced contractility in the posterobasal myocardium (MW -162 +/- 26 vs -80 +/- 7 mm Hg; P < 0.01), accompanied by a delay of regional wall motion within the cardiac cycle (phase 202 +/- 18 vs 223 +/- 17 degrees; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Regional contractile blockade at the onset of reperfusion reduces infarct size in the dog heart

An important mechanism of lethal myocardial reperfusion injury is the development of cellular hypercontracture at the onset of reperfusion. Hypercontracture can lead to cytolysis by mutual mechanical disruption of myocardial cells. 2,3-Butanedione monoxime (BDM) inhibits myofibrillar cross-bridge cycling and may therefore reduce infarct size in ischaemic reperfused myocardium. This study investigated whether a temporary presence of BDM protects against myocardial reperfusion injury in an intact-animal preparation. Anaesthetized open-chest dogs (n = 10) underwent 1 h of left anterior descendent artery (LAD) occlusion and received intracoronary BDM (25 mM, n = 5) or vehicle (n = 5) for 65 min starting with an anoxic local infusion 5 min before reperfusion. Infarct size was assessed by triphenyltetrazolium staining after 6 h reperfusion. The infusion of BDM was accompanied by a transient reduction of left ventricular systolic pressure from 84.3 +/- 11.2 mm Hg during occlusion to 66.4 +/- 9.9 mm Hg at 30 min reperfusion (mean +/- SD, P < 0.01 vs. control). LAD-flow and regional wall motion in the area at risk showed no difference between groups. Infarct size (% of area at risk) was reduced from 24.4 +/- 8.7 (control) to 6.6 +/- 2.0% (BDM) (P < 0.01). The results demonstrate that development of necrosis in reperfused myocardium can be greatly reduced by temporary presence of the contractile inhibitor BDM at the onset of reperfusion.

Ionic currents of Kenyon cells from the mushroom body of the honeybee

The mushroom bodies have been suggested to be essentially involved in learning and memory in insects. In the honeybee Apis mellifera they are composed of about 340,000 intrinsic elements, called Kenyon cells, which can be easily separated from all other neurons of the brain. Here we describe a preparation in which we studied ionic currents in the isolated Kenyon cell somata, using tight-seal whole-cell recording. Several outward and inward currents were identified and investigated by the use of pharmacological agents and in ion substitution experiments: a rapidly inactivating A-type potassium current that is completely blocked with 5 mM 4-aminopyridine; a calcium-activated potassium current that is blocked by 1-100 nM charybdotoxin; a delayed rectifier-type potassium current that is only weakly sensitive to tetraethylammonium but is blocked by 100 microM quinidine; a rapidly activating and inactivating, TTX-sensitive sodium current; a persistent sodium current that is both TTX and cadmium sensitive; and a calcium current that is completely blocked at 50 microM cadmium and is affected by verapamil and nifedipine only at high concentrations (100 microM). The currents described here are very similar to currents found in other insect neurons or muscle cells. This preparation will not only facilitate studies concerning the action of transmitters and neuromodulators that are contained within neurons converging onto the Kenyon cells, but will also allow a study of the role of the adenylyl cyclase pathway, elements of which are expressed in Kenyon cells, and are known to be essential for learning in invertebrates.

Staurosporine inhibits the anaphylactic reaction of the isolated guinea-pig heart

Isolated hearts from ovalbumin sensitized guinea-pigs were perfused according to Langendorff. Ovalbumin injection decreased coronary flow. Left ventricular pressure amplitude and heart rate increased initially and decreased thereafter. Concomitantly, the liberation of histamine, prostaglandin F2 alpha, as well as the sum of leukotrienes C4/D4/E4/F4, measured in the perfusate by radioimmunoassay, was augmented. Staurosporine (1 microM), an inhibitor of protein kinases, did not influence the liberation of mediators in response to antigen challenge, but inhibited all mechanical responses. Infusion of phorbol myristate acetate, an activator of protein kinase C, into non-sensitized hearts decreased coronary flow and left ventricular pressure amplitude, but did not liberate mediators. Staurosporine (1 microM) abolished these mechanical responses. The results indicate that staurosporine suppresses cardiac anaphylaxis by blockage of mediator effects rather than by inhibition of liberation or formation of mediators.