[A pilot project with clowns in psychiatric clinics]

BACKGROUND

This project examines whether visits of specially trained clinic clowns, as established in pediatrics, would also be useful in psychiatry.

METHODS

We describe the effects of a 6-week phase with one clown visit per week in a ward for acutely ill geriatric patients. The patients and medical team were also questioned about their attitudes towards the clowns.

RESULTS

We found more positive attitudes in patients after this phase.

CONCLUSIONS

We interpret this result as an indication of positive effects and sufficient reason to initiate similar projects in the future.

Bone morphogenetic protein-7 expression and activity in the human adult normal kidney is predominantly localized to the distal nephron

Bone morphogenetic protein-7 (BMP)-7 plays an important role during fetal kidney development. In the adult, BMP-7 is most strongly expressed in the kidney compared to other organs, but the exact expression pattern as well as the function of BMP-7 is unclear. The major aim of the present study was to define which parts of the human kidney do physiologically express BMP-7 and which cells appear to be targets of BMP activity by showing phosphorylated BMP-receptor-associated Smads 1, 5, or 8 and inhibitor of differentiation factor 1 (ID1) expression. BMP-7 expression was localized by immunohistology to the epithelia of the distal tubule as well as the collecting ducts (CDs). Phospho-Smads 1/5/8 and ID1 expression largely colocalized with BMP-7 and was also localized in the epithelia of the distal tubule and the CDs. This was confirmed by polymerase chain reaction-based mRNA expression analysis. In vitro, proximal tubular cells (PTCs) expressed BMP receptors and BMP-receptor-associated Smads and were reactive to BMP-7. Our data indicate that BMP-7 expression in the adult human kidney appears to be more restricted than in the fetal situation and predominantly found in the distal nephron. Also, evidence of in vivo BMP signalling (i.e. phospho-Smads and ID1 expression) was found there. These findings suggest that BMP-7 plays a physiological role mostly in this part of the kidney. Still, as reported previously, PTCs are responsive to BMP-7, but presumably not in an autocrine or paracrine mode in normal adult kidneys.

Extracellular carbonic anhydrase activity facilitates lactic acid transport in rat skeletal muscle fibres

1. In skeletal muscle an extracellular sarcolemmal carbonic anhydrase (CA) has been demonstrated. We speculate that this CA accelerates the interstitial CO2/HCO3- buffer system so that H+ ions can be rapidly delivered or buffered in the interstitial fluid. Because > 80 % of the lactate which crosses the sarcolemmal membrane is transported by the H+-lactate cotransporter, we examined the contributions of extracellular and intracellular CA to lactic acid transport, using ion-selective microelectrodes for measurements of intracellular pH (pHi) and fibre surface pH (pHs) in rat extensor digitorum longus (EDL) and soleus fibres. 2. Muscle fibres were exposed to 20 mM sodium lactate in the absence and presence of the CA inhibitors benzolamide (BZ), acetazolamide (AZ), chlorzolamide (CZ) and ethoxzolamide (EZ). The initial slopes (dpHs/dt, dpHi/dt) and the amplitudes (DeltapHs, DeltapHi) of pH changes were quantified. From dpHi/dt, DeltapHi and the total buffer factor (BFtot) the lactate fluxes (mM min-1) and intracellular lactate concentrations ([lactate]i) were estimated. 3. BFtot was obtained as the sum of the non-HCO3- buffer factor (BFnon-HCO3) and the HCO3- buffer factor (BFHCO3). BFnon-HCO3 was 35 +/- 4 mM pH-1 for the EDL (n = 14) and 86 /- 16 mM pH-1 for the soleus (n = 14). 4. In soleus, 10 mM cinnamate inhibited lactate influx by 44 % and efflux by 30 %; in EDL, it inhibited lactate influx by 37 % and efflux by 20 %. Cinnamate decreased [lactate]i, in soleus by 36 % and in EDL by 45 %. In soleus, 1 mM DIDS reduced lactate influx by 18 % and efflux by 16 %. In EDL, DIDS lowered the influx by 27 % but had almost no effect on efflux. DIDS reduced [lactate]i by 20 % in soleus and by 26 % in EDL. 5. BZ (0.01 mM) and AZ (0.1 mM), which inhibit only the extracellular sarcolemmal CA, led to a significant increase in dpHs/dt and pHs by about 40 %-150 % in soleus and EDL. BZ and AZ inhibited the influx and efflux of lactate by 25 %-50 % and reduced [lactate]i by about 40 %. The membrane-permeable CA inhibitors CZ (0.5 mM) and EZ (0.1 mM), which inhibit the extracellular as well as the intracellular CAs, exerted no greater effects than the poorly permeable inhibitors BZ and AZ did. 6. In soleus, 10 mM cinnamate inhibited the lactate influx by 47 %. Addition of 0.01 mM BZ led to a further inhibition by only 10 %. BZ alone reduced the influx by 37 %. 7. BZ (0.01 mM) had no influence on the Km value of the lactate transport, but led to a decrease in maximal transport rate (Vmax). In EDL, BZ reduced Vmax by 50 % and in soleus by about 25 %. 8. We conclude that the extracellular sarcolemmal CA plays an important role in lactic acid transport, while internal CA has no effect, a difference most likely attributable to the high internal vs. low extracellular BF(non-HCO3). The fact that the effects of cinnamate and BZ are not additive indicates that the two inhibitors act at distinct sites on the same transport pathway for lactic acid.

Contraction parameters, myosin composition and metabolic enzymes of the skeletal muscles of the etruscan shrew Suncus etruscus and of the common European white-toothed shrew Crocidura russula (Insectivora: soricidae)

In the Etruscan shrew, the isometric twitch contraction times of extensor digitorum longus (EDL) and soleus muscles are shorter than in any other mammal, allowing these muscles to contract at outstandingly high contraction frequencies. This species has the highest mass-specific metabolic rate of all mammals and requires fast skeletal muscles not only for locomotion but also for effective heat production and for an extremely high ventilation rate. No differences could be detected in the fibre type pattern, the myosin heavy and light chain composition, or in the activity of the metabolic enzymes lactate dehydrogenase and citrate synthase of the two limb muscles, the EDL and the soleus, which in larger mammalian species exhibit distinct differences in contractile proteins and metabolic enzymes. All properties determined in EDL and soleus muscles of Suncus etruscus, as well as in the larger Crocidura russula, are typical for fast-oxidative fibres, and the same holds for several other skeletal muscles including the diaphragm muscle of S. etruscus. Nevertheless, the EDL and soleus muscles showed different mechanical properties in the two shrew species. Relaxation times and, in C. russula, time to peak force are shorter in the EDL than in the soleus muscle. This is in accordance with the time course of the Ca(2+) transients in these muscles. Such a result could be due to different parvalbumin concentrations, to a different volume fraction of the sarcoplasmic reticulum in the two muscles or to different Ca(2+)-ATPase activities. Alternatively, the lower content of cytosolic creatine kinase (CK) in the soleus compared with the EDL muscle could indicate that the observed difference in contraction times between these shrew muscles is due to the CK-controlled activity of their sarcoplasmic reticulum Ca(2+)-ATPase.

Inhibition and kinetic properties of membrane-bound carbonic anhydrases in rabbit skeletal muscles

It was the aim of this study to investigate whether the carbonic anhydrases associated with the sarcoplasmic reticulum (SR) and sarcolemmal membranes differ in their kinetic and inhibitory properties. To this end, sarcolemmal and SR membrane vesicle fractions were prepared from rabbit white and red skeletal muscles, the white muscle sarcolemmal fraction (WSL), the red muscle sarcolemmal fraction (RSL), the white muscle SR fraction (WSR), and the red muscle SR fraction (RSR). WSL displayed a specific carbonic anhydrase activity of 22.1 U . ml/mg and RSL of 7.5 U . ml/mg, whereas the SR fractions showed a much lower activity of 0.5 U . ml/mg for WSR and of 2.4 U . ml/mg for RSR. In both SR fractions phase separation experiments with Triton X-114 demonstrated that the carbonic anhydrase activity is due to a membrane-bound enzyme and not due to a cytosolic isozyme. The kinetic properties of carbonic anhydrase from the four distinct membane fractions were evaluated by determination of the Michaelis constant, Km, and of the catalytic centre activity kcat. Km appears to be somewhat lower for SR than for SL. Inhibition constants of SR and SL carbonic anhydrases were determined applying six carbonic anhydrase inhibitors: chlorzolamide, ethoxzolamide, methazolamide, benzolamide, and acetazolamide, and also cyanate. The inhibition constants of the SR fractions were significantly different from those of the corresponding sarcolemmal fractions, indicating that the carbonic anhydrase measured in the SR fractions does not originate from contaminating sarcolemmal membrane vesicles, but appears to represent a distinct carbonic anhydrase associated with the SR membrane.

Decay of Ca2+ and force transients in fast- and slow-twitch skeletal muscles from the rat, mouse and Etruscan shrew

Isometric single-twitch force and intracellular Ca2+ transients were recorded simultaneously, using fura-2, from slow- and fast-twitch muscle fibres of the rat, mouse and Etruscan shrew Suncus etruscus. In the slow-twitch rat soleus, force half-relaxation time was three times longer than the 50 % decay time of the fura-2 signal. In contrast, in the fast-twitch extensor digitorum longus muscles of all three animals, muscle relaxation preceded Ca2+ decay. It is proposed that this surprising property of fast-twitch muscles is due to their pCa­tension curve, which is shifted to the right compared with that of slow-twitch muscle.

Decay of Ca2+ and force transients in fast- and slow-twitch skeletal muscles from the rat, mouse and Etruscan shrew

Isometric single-twitch force and intracellular Ca2+ transients were recorded simultaneously, using fura-2, from slow- and fast-twitch muscle fibres of the rat, mouse and Etruscan shrew Suncus etruscus. In the slow-twitch rat soleus, force half-relaxation time was three times longer than the 50% decay time of the fura-2 signal. In contrast, in the fast-twitch extensor digitorum longus muscles of all three animals, muscle relaxation preceded Ca2+ decay. It is proposed that this surprising property of fast-twitch muscles is due to their pCa-tension curve, which is shifted to the right compared with that of slow-twitch muscle.

Adult fast myosin pattern and Ca2+-induced slow myosin pattern in primary skeletal muscle culture

A primary muscle cell culture derived from newborn rabbit muscle and growing on microcarriers in suspension was established. When cultured for several weeks, the myotubes in this model develop the completely adult pattern of fast myosin light and heavy chains. When Ca2+ ionophore is added to the culture medium on day 11, raising intracellular [Ca2+] about 10-fold, the myotubes develop to exhibit properties of an adult slow muscle by day 30, expressing slow myosin light as well as heavy chains, elevated citrate synthase, and reduced lactate dehydrogenase. The remarkable plasticity of these myotubes becomes apparent, when 8 days after withdrawal of the ionophore a marked slow-to-fast transition, as judged from the expression of isomyosins and metabolic enzymes, occurs.

Rat skeletal muscle membrane associated carbonic anhydrase is 39-kDa, glycosylated, GPI-anchored CA IV

Sarcolemmal membrane vesicle preparations from white and red muscles of rat were found to contain a carbonic anhydrase which was indistinguishable from carbonic anhydrase IV from rat lung. This isozyme appears to account for all of the carbonic anhydrase activity in the sarcolemmal vesicle preparations. Digestion of 39-kDa CA IV with endoglycosidase F reduced the Mr to 36 kDa, suggesting that it contains one N-linked oligosaccharide. Treatment of sarcolemmal vesicles with phosphatidylinositol-specific phospholipase C released all of the activity, indicating that the enzyme is anchored to membranes by a phosphatidylinositol-glycan linkage. White muscle sarcoplasmic reticulum vesicles also contain a small amount of 39-kDa CA IV-type enzyme. A 52-kDa polypeptide in sarcoplasmic reticulum membranes cross-reacts with anti-human CA II and anti-rat CA II antisera, but does not bind to the sulfonamide affinity column. This cross-reacting polypeptide has no detectable CA activity.

Is Carbonic anhydrase Required for Contraction of Skeletal Muscle?

An important step in excitation-contraction doupling is release and reuptake of Ca2+ at the sarcoplasmic reticulum membrane, which requires simultaneous transfer of counterions, probably H+. Evidence is provided that a carbonic anhydrase associated with the sarcoplasmic reticulum membrane rapidly generates the H+ necessary for this exchange.

Carbonic anhydrase inhibition and calcium transients in soleus fibers

We simultaneously measured cytoplasmic Ca2+ transients using Fura-2 and isometric force in rat soleus fiber bundles. In the presence of the carbonic anhydrase inhibitor, chlorzolamide, we observed a decreased amplitude and retarded decay of the Ca2+ signal. This corresponded with a decreased isometric force and a retarded muscle relaxation. We conclude that muscle carbonic anhydrase participates in excitation-contraction coupling, possibly by rapidly providing protons that are exchanged for Ca2+ across the sarcoplasmic reticulum membrane.

Sarcolemmal carbonic anhydrase in red and white rabbit skeletal muscle

Sarcolemmal vesicles of white and red skeletal muscles of the rabbit were prepared by consecutive density gradient centrifugations in sucrose and dextran according to Seiler and Fleischer (1982, J. Biol. Chem. 257, 13,862-13,871). White and red muscle membrane fractions enriched in sarcolemma were characterized by high ouabain-sensitive Na+, K(+)-ATPase, by high Mg2(+)-ATPase activity, and by a high cholesterol content. Ca2(+)-ATPase activity, a marker enzyme for sarcoplasmic reticulum, was not detectable in the highly purified white and red muscle sarcolemmal fractions. White and red muscle sarcolemmal fractions exhibited no significant differences with regard to Na+, K(+)-ATPase, Mg2(+)-ATPase, and cholesterol. Specific activity of carbonic anhydrase in white muscle sarcolemmal fractions was 38 U.ml/mg and was 17.6 U.ml/mg in red muscle sarcolemma. Inhibition properties of sarcolemmal carbonic anhydrase were analyzed for acetazolamide, chlorzolamide, and cyanate. White muscle sarcolemmal carbonic anhydrase is characterized by inhibition constants, KI, toward acetazolamide of 4.6 X 10(-8) M, toward chlorzolamide of 0.75 X 10(-8) M, and toward cyanate of 1.3 X 10(-4) M. Red muscle sarcolemmal carbonic anhydrase is characterized by KI values toward acetazolamide of 8.1 X 10(-8) M, toward chlorzolamide of 6.3 X 10(-8) M, and toward cyanate of 0.81 X 10(-4) M. In contrast to the high specific carbonic anhydrase activities in sarcolemma, carbonic anhydrase activity in sarcoplasmic reticulum from white muscle varied between values of only 0.7 and 3.3 U.ml/mg. Carbonic anhydrase of red muscle sarcoplasmic reticulum ranged from 2.4 to 3.7 U.ml/mg.

Dynamic contributions of the components of binocular vergence

Experimental results from step stimulation of the two major dynamic components in ocular vergence showed that while fusional covergence dominated a coordinated binocular vergence movement, accomodative convergence always contributes to the dynamic response. A quantitative analysis of component dynamics, both in isolation and during coordinated movements, indicates that these components are additive at least through a portion of the movement. Two alternative hypotheses are presented for the role of accommodative convergence during the period immediately following a binocular vergence movement.