The continuous measurement of tubular volume changes in response to step changes in contraluminal osmolality

A new method to measure time dependent (t) volume (V) changes in proximal straight tubules (PST) is described.V is calculated from diameter (d) measurements for which a video camera and an integrating circuit are used. A tubular image of high optical contrast is recorded with the TV camera such that the scan lines run crosswise to the tubule. The video signal is analyzed by a special processor which adds 225 tubular diameters of each TV frame and feeds this analog signal to a pen recorder. The fractional error ind measurements is 10^–3. Diameter changes of less than 0.05 m can be detected, as compared to the usual error of a single measurement of about 0.4 m.P _os ^cb , the osmotic water permeability of the contraluminal cell membrane was measured by setting up osmotic steps across it in less than 0.1 s and following the ensuing d/t. the time delay between solution change and the linear part of the osmotic response was 0.51±0.05 s.P _os ^cb was found to be 50.4 (±8.7)×10^–4 cm³·cm^–2 of basement membrane area ·s^–1·osmolar^–1.     

Processing of binaural stimuli by cat superior olivary complex neurons

Summary A method was developed to record stereotactically from the cat Superior Olivary Complex (SOC) using glass micropipettes. Sound stimulation was given through a closed system that permitted independent variation of interaural time (time) and intensity (int) differences. The most common binaural units found (n = 34) were ipsilateral excitatory, contralateral inhibitory (EI¹), cells of the Lateral Superior Olive (LSO). Some Medial Superior Olive (MSO) cells and presumed MSO ascending afferents were found but, as noted by other authors, we found it difficult to obtain single unit recordings from this nucleus. The LSO EI cells were mostly sensitive to higher frequencies and showed Peristimulus Time Histograms (PSTHs) consisting of a sharp On response followed by a plateau when stimulated with Best Frequency (BF) tone bursts or noise bursts. This On response was sensitive to time and int such that ipsilateral time lead or intensity increase resulted in a stronger response. The response reached a minimum around zero time or int. No sharp peaks or dips were seen in the physiological range needed for localization, instead the response increased with increasing ipsilateral lead or intensity to the maximum values tested (2048 s time, 30 dB int). In the physiological range the time and int response were complementary (both increasing response as ipsilaterality was increased). Provided enough sound energy in the unit's sensitive region was present, the same time curves were produced when BF tone bursts, masked tone bursts, sharp onset tone bursts or noise bursts were used. Changing the time of the carrier of the tone burst alone had no effect (except for one cell with a BF of 560 Hz), only the relative time of arrival of the stimulus envelope seemed to be important. In contrast to these LSO EI cells MSO-type units showed EI or EE predominantly low frequency phase-locked responses. When stimulated with interaurally phase shifted (pha) BF tones the unit response was a cyclic function of pha. Some cells (all that were tested, n = 6 including the 560 Hz LSO EI cell) showed these cyclic responses when stimulated with noise bursts or non-BF tones. However, these characteristic delays were not necessarily in the physiological range, i.e. we could find no evidence that these units were responding to time/pha values corresponding to a particular sound source direction. In both LSO and MSO it seems that integration of information higher in the CNS from a population of these cells is necessary for unambiguous coding of sound source direction. The time intensity trading ratios measured in two MSO type cells (11 and 26 /dB) were clearly different to those measured in LSO EI cells (n = 6, 99–550 s/dB). These ratios correspond approximately to those of the psychophysical time and int images measured by Hafter and Jeffress (1968).Supported by the Deutsche Forschungsgemeinschaft (SFB 45)     

Bidirectional active transport of thiosulfate in the proximal convolution of the rat kidney

Using the standing droplet method in the late proximal convolution and simultaneous microperfusion of the peritubular capillaries, the zero net flux transtubular concentration difference of thiosulfate at 45 s was determined, the latter being taken as a measure of active thiosulfate transport. Under control conditions, in the presence of Na⁺, near zero c values were observed. When 1 mmol/l carinamide or paraaminohippurate (PAH) were added to the perfusates significant reabsorptive c arose. However, when 7.5 mmol/l sulfate was added to the Na⁺-free secretory c values were observed. Tested under Na⁺-free conditions, the secretory c was not influenced by simultaneously present 5 mmol/l of SO ₄ ^2– but was diminished by 50 mmol/l SO ₄ ^2– . PAH (1 mmol/l), carinamide (0.2 mmol/l) and probenecid (1 mmol/l) decreased the secretory c by 48, 65 and 48%, respectively. The PAH secretion was not influenced, when thiosulfate or sulfate up to 50 mmol/l was added to both perfusates. Under Na⁺-free conditions the c of thiosulfate in early loops of the proximal convolution is higher than in late loops, while for PAH this pattern is reversed. Taken together with the previously published inhibition of sulfate reabsorption by thiosulfate the data indicate 1. thiosulfate is reabsorved by the Na⁺-dependent sulfate transport system and 2. thiosulfate is simultaneously secreted by a carinamide-, probenecid-and PAH-sensitive secretory system. The secretory system might also be shared by sulfate. The thiosulfate net flux is the result of the difference in the activity of the counteracting transporters, located at the luminal and contraluminal cell side. Is is possible that the higher activity of the transporter at one cell side leads to a reversal of the flux through the transporter at the other cell side.     

Indices for the role played by regional flow resistance in blood pressure reflex

Summary An index, = (r/r)/(R/R), is proposed for assessment of the relative degree of participation of a regional flow resistance in a blood pressure reflex, wherer andR are regional and total peripheral resistances respectively and 's refer to their reflexive changes. For actual computation, =I (iP – Pi)/i(IP – PI), whereI=cardiac output,i=regional flow rate,P=mean arterial pressure. When the change in cardiac output is neglegible, the above equation is simplified as =1 – Pi/iP. Another index, = g/G = (Pi – iP)/(PI – IP), is introduced for the degree of contribution of a region to a reflex, whereg andG are regional and total conductances.i = 1. Some examples of application of the indices are presented.Supported in part by a grant from the Ministry of Education of Japan.     

Water absorption and swelling in the rat small intestine in vitro

Summary Net mucosal-to-serosal water transport and water retention within the tissue were simultaneously measured in the isolated, everted rat jejunum and ileum along with time.The swelling of the epithelium (w/DW-v/DW) precedes the absorption of fluid and then it remains constant throughout the experiment.The water uptake, determined as a weight increase, (w/DW) and the net water transport determined as a serosal volume increase (v/DW) were higher in Krebs-Ringer-bicarbonate than in a Krebs-Ringer-phosphate medium.In the jejunum glucose markedly stimulated both the tissue retention and net transport of water, but such effect was not seen in the ileum.Replacement of chloride with sulphate in the medium diminishes both water transport and retention, but both were markedly stimulated by the addition of glucose to such medium.As a conclusion it seems that during water transport the epithelial layer swells and the swelling increases when the amount of water transported is increased.     

Über zwei neue anabol wirksame Steroide

Zusammenfassung 1-Methyl- ¹-androsten-17-ol-3-on-17-acetat ist unter zahlreichen von uns geprüften das zur Zeit am stärksten wirksame anabole Steroid mit der relativ geringsten androgenen Nebenwirkung. Die Beeinflussung des Cyclus bei der normalen Ratte ist gering. Eine Überlegenheit gegenüber Testosteron-17-propionat tritt am chronisch dihydrotachysterin-vergifteten Tier deutlich hervor, die sich neben der Erhaltung des Körpergewichts in der Verhütung unphysiologischer Ca-Ablagerungen manifestiert. Die anti-ulcerogene Wirkung des 1-Methyl- ¹-androsten-17-ol-3-on-17-acctat ist gleich der des Testosteron-17-propionat; hier liegt die Überlegenheit des 1-Methyl- ¹-androsten-17-ol-3-on-17-acetats in seiner schwächeren androgenen Nebenwirkung.Das 1-Methyl- ¹-androsten-17-ol-3-on-17-önanthat zeigt besonders starke und langdauernde anabole Wirkung bei sehr geringer und wesentlich kürzerer androgener Wirksamkeit.     

Quantitative and sustained suppression of renal sympathetic nerve activity by left atrial distension in conscious dogs

In order to investigate the interrelations between left atrial pressure (Pla) and renal sympathetic nerve activity (RSNA) and heart rate (HR), Pla was increased by a balloon both in conscious sham-operated and cardiac-denervated dogs. RSNA was decreased and HR was increased with increasing Pla in sham-operated dogs. The reflex changes in RSNA and HR induced by the stimulation of atrial receptors persisted for at least 15 min. There was a consistent relationship between Pla and RSNA which could be described by a single exponential equation: % RSNA = 80.0(1–e^{–0.395 Pla}), or by a linear equation when Pla was less than 6 mmHg; %RSNA=-13.5Pla–2.25. The relationship between Pla and HR can be described by a single exponential equation: HR = 86.5(1–e^{–0.125 Pla}). A significant linear relationship between RSNA and HR was obtained during a graded left atrial distention (%RSNA=-1.08HR–17.7). In cardiac-denervated dogs, RSNA tended to increase and HR remained constant during the left atrial distention. These results indicate that left atrial receptors regulate RSNA and HR in both a quantitative and sustained manner in conscious sham-operated dogs.     

Klinische Wertigkeit der gleichzeitigen Bestimmung der Plasma-Konzentrationen des Beta-2-Mikroglobulin (β2m) und des Carzino-embryonalen Antigens (CEA) bei der Erstdiagnostik und der Beurteilung der Operationsradikalität von Adenokarzinomen des Verdauungstraktes

Zusammenfassung Zum einen wurde untersucht, ob durch gleichzeitige Bestimmung von ₂ m und CEA die diagnostischeSpezifität oderEmpfindlichkeit dieser Teste für die Erstdiagnose von gastrointestinalen Adeno-Karzinomen erhöht werden kann. Wegen der Erhöhung der Plasmakonzentrationen des ₂ m und des CEA auch bei entzündlichen gastrointestinalen Erkrankungen wurde eine klinische Relevanzgrenze von 3,0 mg/l für das ₂ m und von 5,0 µg/l für das CEA zur Unterscheidung maligne — nicht maligne festgesetzt. Bei Patienten mit Kolon-Rektum-Karzinom (n=42) waren die ₂ m- bzw. CEA-Plasmakonzentrationen in 17% bzw. 29% erhöht. Eine Erhöhung wenigstens eines der beiden Antigene brachte im Vergleich mit einer Erhöhung des CEA alleine keine wesentliche Verbesserung der diagnostischen Empfindlichkeit. Eine gleichzeitige Erhöhung beider Antigene, d.h. eine Verbesserung der diagnostischen Spezifität war beschränkt auf das Dukesstadium D. Bei Magen-Karzinomen (n=15) erbrachte die gleichzeitige Bestimmung keine zusätzliche Information verglichen mit der CEA-Bestimmung alleine.Zum anderen wurden in einer prospektiven Studie bei 41 Patienten mit Kolon-Rektum- (n=29) oder Magen-Adenokarzinom (n=12) sowohl präoperativ als auch während der ersten 4 postoperativen Monate die ₂ m- und CEA-Plasmakonzentrationen bestimmt. Von 29 potentiell kurativ resezierten Patienten waren die Konzentrationen des ₂ m bei 72% unmittelbar postoperativ zunächst stark angestiegen und nach 4 Monaten noch bei 40% erhöht, wogegen sich nach dieser Zeit die Plasmakonzentrationen des CEA mit Ausnahme von 4 Patienten normalisiert hatten. Bei 3 dieser 4 Patienten zeigte der weitere Verlauf, daß nicht kurativ reseziert worden war. Nur einer dieser Patienten hatte eine konstant ansteigende Verlaufstendenz der ₂ m-Plasmakonzentration.Wegen dieses starken Einflußes postoperativer Entzündungsprozeße auf die ₂ m-Plasmakonzentration ist die Bestimmung derselben — im Gegensatz zur CEA-Plasmakonzentration — zur Früherkennung der nicht kurativen Resektion gastrointestinaler Adenokarzinome nicht geeignet.     

Ca2+ can affectV max without changes in myosin light chain phosphorylation in smooth muscle

The effects of elevated [Ca²⁺]_o on crossbridge cycling rate, measured as maximum velocity of shortening (V _max) and high energy phosphate usage (P), and on the degree of phosphorylation of the 20,000-dalton light chain of myosin (MyLCP) during an isometric tetanus were determined in the rabbit taenia coli at 18°C. In an normal Krebs medium (1.9 mM Ca²⁺) the average rate of P during force development is 4xhigher than during force maintenance. In 4.5 mM Ca²⁺-Krebs, the average rate of P increases by 100% during force development and during force maintenance above that observed in normal Krebs medium, with no significant change in force output.V _max increased in the high Ca²⁺ medium, in good agreement with the corresponding rates of P, but without any significant change in the degree of MyLCP. Also, in both high and low calcium media,V _max decreased with tetanus duration as did the P; however, the degree of phosphorylation was not directly related to the average rate of energy usage during the two phases of the tetanus. Therefore, in intact smooth muscles Ca²⁺-dependent and time-dependent changes inV _max and average rate of P can occur without corresponding changes in MyLCP. Modulation of crossbridge cycling rate may be accomplished by a Ca²⁺-dependent process in addition to MyLCP.     

Increase of whole blood lactic acid concentration during exercise as predicted from pH andPCo 2 determinations

In 67 test subjects, an attempt was made to establish whether it is possible to predict the change in the lactic acid concentration of the arterial blood during excercise from the calculated metabolic change in the bicarbonate concentration of the arterial blood during exercise. The changes in the HCO ₃ ^– and the lactic acid concentration averaged —4.15 and 4.41 mEq./l, respectively.It was found possible to predict the measured change in lactic acid concentration from the change in HCO ₃ ^– concentration calculated from the pH and the P Co ₂. A respiratory correction in the calculation ensured the best correlation coefficient (0.81).The regression equation was lactic acid=0.29–0.99 HCO ₃ ^– metabolic.An equally good approximation was attained in calculating the change of lactic acid concentration from the total change in bicarbonate concentration, with application of a simplified respiratory correction: lactic acid=0.33–0.97 (HCO ₃ ^– total –0.18 P Co ₂).The correlation coefficient remained 0.81.With 1 Figure in the TextStudy supported by the European Coal and Steel Community and the Organization for Health Research T.N.O., Netherlands.With the technical assistance of Miss M. L. Hamelink, Mrs. G. de Leeuw-Van Zandwijk and Mr. K. A. Foest.Present address: Dept. of Cardiology.     

Ultrasonography gives directly but noninvasively elastic characteristic of human tendon in vivo

To obtain an insight into tendon elasticity during human movement, a real-time ultrasonography was applied to the contracting tibialis anterior muscle. The insertion point of fascicles onto the aponeurosis was clearly visualized, and its position relative to a fixed marker on the skin moved proximally (1) according to the increasing dorsiflexion force (F) with a fixed ankle joint. Notably, the 1 – F relationship in the tendon was found to be quadratic in nature (F = c1²; c=1.48 2.24, r=0.985 0.992, n=9) as has been reported in the isolated tendon, although the F – 1 curves were slightly underestimated in comparison with the stiffness constant estimated from tendon architecture. This underestimation might be caused by changes in the height of the foot arch with the application of force.     

Interactions of the RAD7 and RAD23 excision repair genes of Saccharomyces cerevisiae with DNA repair genes in different epistasis groups

Summary The RAD7 and RAD23 genes of S. cerevisiae affect the efficiency of excision repair of UV-damaged DNA. We have examined the UV survival of strains carrying the rad7 or rad23 deletion mutation in combination with deletion mutations in genes affecting different DNA repair pathways. As expected, the rad7 and rad23 mutations interact epistatically with the excision repair defective rad1 mutation, and synergistically with the rad6 and rad52 mutations that affect the postreplication repair and recombinational repair pathways, respectively. However, the rad7rad6 and the rad23rad6 mutants exhibit the same level of UV sensitivity as the radlrad6 mutant. This observation is of interest since, in contrast to the rad7 or the rad23 mutations, the rad1 mutant is very UV sensitive and highly excision defective. This observation suggests that RAD6 and RAD7 and RAD23 genes compete for the same substrate during DNA repair.     

Antiandrogentherapie der pathologisch gesteigerten und abartigen Sexualität des Mannes

Zusammenfassung Mit 100 mg Cyproteronacetat (1.2-Methylen-6-chlor-^4,6-pregnadien-17-ol-3.20-dion-17-acetat) pro Tag per os konnten innerhalb von 10–14 Tagen Libido und Potenz hypersexuell bzw. abartig sexuell erregter Männer unabhängig vom Lebensalter in bisher 17 behandelten Fällen ohne Therapieversager und ohne wesentliche Nebenwirkungen gehemmt werden.

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Summary With 100 mg Cyproteroneacetate (1.2-methylene-6-chloro-^4,6-pregnadiene-17-ole-3.20-dione-17-acetate) orally applied per day libido and potency of men suffering from hyper- or abnormal sexuality were inhibited within 10 to 14 days independent from the age of the patients in 17 cases up to this time without any failure in therapy and without fundamental side effects.

     

Influence of muscle fibre type and pedal rate on the V̇O2-work rate slope during ramp exercise

We hypothesised that the ratio between the increase in oxygen uptake and the increase in work rate (O₂/WR) during ramp cycle exercise would be significantly related to the percentage type II muscle fibres at work rates above the gas exchange threshold (GET) where type II fibres are presumed to be active. We further hypothesised that ramp exercise at higher pedal rates, which would be expected to increase the proportional contribution of type II fibres to the total power delivered, would increase the O₂/WR slope at work rates above the GET. Fourteen healthy subjects [four female; mean (SD): age 25 (3) years, body mass 74.3 (15.1) kg] performed a ramp exercise test to exhaustion (25 W min^–1) at a pedal rate of 75 rev min^–1, and consented to a muscle biopsy of the vastus lateralis. Eleven of the subjects also performed two further ramp tests at pedal rates of 35 and 115 rev min^–1. The O₂/WR slope for exercise <GET (S ₁) was significantly correlated with O₂ peak in ml kg^–1 min^–1 (r=0.60; P<0.05), whereas the O₂/WR slope for exercise >GET (S ₂) was significantly correlated to percentage type II fibres (r=0.54; P=0.05). The ratio between the O₂/WR slopes for exercise above and below the GET (S ₂/S ₁) was significantly greater at the pedal rate of 115 rev min^–1 [1.22 (0.09)] compared to pedal rates of 35 rev min^–1 [0.96 (0.02)] and 75 rev min^–1 [1.09 (0.05), (P<0.05)]. The greater increase in S ₂ relative to S ₁ in subjects (1) with a high percentage type II fibres, and (2) at a high pedal rate, suggests that a greater recruitment of type II fibres contributes in some manner to the xs O₂ observed during ramp exercise.     

Gap junctional conductance tunes phase difference of cholecystokinin evoked calcium oscillations in pairs of pancreatic acinar cells

Summary Using the double whole-cell recording technique we measured the gap junctional conductance (g_j), while simultaneously monitoring the cytoplasmic free calcium concentration ([Ca_i ²⁺]) in isolated acinar cell pairs from the pancreas of mouse. Physiological concentrations of the secretagogue cholecystokinin-octapeptide (CCK-OP) elicited [Ca_i ²⁺] oscillations and after a delay in the minute range reduced g_j. The results provide the first evidence suggesting that g_j regulates the phase difference () of [Ca_i ²⁺] oscillations between neighbouring cells not in an all or none process, but with decreasing absolute value of g_j monotonically increases. CCK-OP induced electrical uncoupling as well as the corresponding increase of could be blocked completely by the protein kinase C inhibitor polymyxin B. The data support the hypothesis that Ca²⁺ flow through gap junctions synchronizes [Ca_i ²⁺] oscillations between gap junctional coupled cells.     

Klinische,morphologische und biochemische Untersuchungen bei einem androgenbildenden Hodentumor

Zusammenfassung Bei einem Knaben mit einer Pseudopubertas praecox wurde ein androgenproduzierender Hodentumor entfernt. Präoperativ war die Harnausscheidung der gesamten 17-Ketosteroide, von Androsteron und Ätiocholanolon, der 11-Oxy-17-Ketosteroide, insbesondere von 11-Hydroxy-androsteron, von Pregnandiol, Pregnantriol sowie der Oestrogene abnorm erhöht und fiel nach der Operation auf Normwerte ab. Nach Inkubation von Glucose allein mit Tumorschnitten wurden 11-Hydroxy- ⁴-androstendion und ⁴-Androstendion gefunden, nach Inkubation von ⁴-Androstendion: 11-Hydroxy- ⁴-androstendion, Testoseron und Adrenosteron, jedoch keine Oestrogene, nach Inkubation von Desoxycorticosteron: Corticosteron und 17-Hydroxy-desoxy-corticosteron. Im V. spermatica-Blut wurden große Mengen ⁴-Androstendion, ferner 17-Hydroxy-progesteron, 11-Hydroxy- ⁴-androstendion und Testosteron nachgewiesen.Die biochemischen und morphologischen Gesichtspunkte sowie die klinischen Auswirkungen des Tumors werden diskutiert. Morphologisch hatte der Tumor den Aspekt eines Leydigzell-Adenoms. In Übereinstimmung hiermit wurde eine hohe Sekretion von Androgenen festgestellt. Durch den Nachweis einer 11-Hydroxylase-Aktivität zeigte der Tumor jedoch gleichzeitig eine Eigenschaft, die sonst nur NNR-Zellen zukommt. Der Tumor wird vermutungsweise von atypischen Leydigzellen abgeleitet.Diese Art von Leydigzell-Adenom wird der beidseitigen tumorartigen Hodenvergrößerung, die gelegentlich beim angeb. adrenogenitalen Syndrom beobachtet wird, gegenübergestellt. Die gemeinsamen und unterschiedlichen Eigenschaften der beiden Wucherungen werden besprochen.

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Summary An androgen producing tumour of the testis was removed from a boy with pseudopubertas praecox. Urinary excretion of total 17-oxosteroids, androsterone and aetiocholanolone, 11-oxy-17-oxosteroids (particularly 11-hydroxy-androsterone), pregnandiol, pregnantriol and oestrogens were abnormally high before operation, and had decreased to normal after operation. After incubation of tumour slices with glucose alone androst-4-en-3,17-dione and 11-hydroxyandrost-4-en-3,17-dione were found; after incubation with androst-4-en-3,17-dione: 11-hydroxyandrost-4-en-3,17-dione, testosterone and adrenosterone, but no oestrogens were found; after incubation with desoxycorticosterone: corticosterone and 17-hydroxycorticosterone. A large amount of androst-4-en-3,17-dione was found in Vena spermatica blood, as well as 17-hydroxyprogesterone, 11-hydroxyandrost-4-en-3,17-dione and testosterone.The biochemical and morphological aspects are discussed in relation to the clinical manifestations of the tumour. The tumour had the morphological appearance of a Leydig cell adenoma and also showed a high rate of androgen secretion. The finding of 11-hydroxylase activity in the tumour shows that it possessed a characteristic usually found only in adrenocortical cells. The tumour was conceivably derived from atypical Leydig cells.This type of Leydig cell adenoma is compared with the bilateral tumour-like enlargement of the testis, which is ocassionally observed in congenital adrenogenital syndrome. The common and contrasting characteristics of the two growths are discussed.

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Herrn Prof. Dr.E. Rehn zum 85. Geburtstag gewidmet.     

Effects of tone intensity and frequency on discrimination of the sound stimulus transition process

In our research, we determined the dependence of human detection of differences in the sound stimulus transition process, upon sound intensity and frequency. We established that the discrimination threshold for the stimulus rise time (_r) is approximately 1.5 msec at low and intermediate tone frequencies and increases to 5–6 msec during an increase in frequency from 10 to 15 kHz. It was shown that the ability of a human to discriminate a stepwise change in the stimulus envelope depends upon the duration of the steps. For steps of short duration (up to 7 msec), a linear decrease in the discrimination threshold value for detecting a drop in step amplitude (I) occurs with increasing duration of the step (t). For a step duration greater than 7 msec, the discrimination threshold for a drop in amplitude remains constant, equaling a value on the order of 3.5 dB. It was found that the values of _r and I rapidly decrease with an increasing level of stimulus intensity in the range of 10–40 dB and remain practically constant in the range of 40–80 dB.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 73, No. 8, pp. 1078–1083, August, 1987.     

Effect of menstrual cycle and gender on ventilatory and heart rate responses at the onset of exercise

To clarify the luteal-follicular and male–female differences in ventilatory and heart rate responses at the onset of exercise, seven women and seven men performed voluntary exercise and passive movement for 20 s (brief voluntary exercise and brief passive movement) and voluntary exercise for 3 min (long voluntary exercise) in a sitting position. Voluntary exercise consisted of alternate flexion-extensions of both lower legs with a weight corresponding to about 2.5% of the subjects' body mass attached to each ankle, at a frequency of about 60 times min^–1. Passive movement was carried out without weights by experimenters pulling ropes attached to both of the subjects' ankles, in the same way as voluntary exercise. During these exercises and movements, minute inspiratory ventilation (_I) and heart rate (HR) were continuously measured by breath-by-breath and beat-to-beat techniques. We calculated relative changes of _I and HR (_I and HR). Additionally, we averaged _I and HR obtained during the exercise and movement for each subject, and performed a correlation analysis between the averaged _I and HR. It was clarified that: (1) _I and HR in the follicular phase were almost equal to those in the luteal phase; (2) there were no significant male–female differences in these parameters; (3) significant positive correlations were found in both genders only during brief voluntary exercise. We conclude that ventilatory and HR responses at the onset of voluntary exercise and passive movement are not affected by the menstrual cycle or gender.     

Exogenous gene expression and growth regulation of hematopoietic cells via a novel human artificial chromosome

A number of gene delivery systems are currently being developed for potential use in gene therapy. Here, we demonstrate the feasibility of 21qHAC, a newly developed human artificial chromosome (HAC), as a gene delivery system. We first introduced a 21qHAC carrying an EGFP reporter gene and a geneticin-resistant gene (EGFP-21qHAC) into hematopoietic cells by microcell-mediated chromosome transfer. These HAC-containing hematopoietic cells showed resistance to geneticin, expressed EGFP and retained the ability to differentiate into various lineages, and the EGFP-21qHAC was successfully transduced into primary hematopoietic cells. Hematopoietic cells harboring the EGFP-21qHAC could still be detected at two weeks post-transplantation in immunodeficient mice. We also showed effective expansion of hematopoietic cells by introducing the 21qHAC containing ScFvg, a gp130-based chimeric receptor that transmits growth signals in response to specific-antigen of this receptor. All of these results demonstrate the usefulness of HAC in gene therapy.     

Ankoppelung und Entkoppelung während der Kaliumchloridkontraktur

Zusammenfassung Bei Herzpräparaten von Aplysia führen schnelle Entdehnungen während isometrischer Kontrakturen, die durch verschiedene KCl-Konzentrationen ausgelöst werden, im Anschluß an den elastischen Spannungsabfall zu einem nachfolgenden Spannungsanstieg () über das Niveau der elastischen Nachwirkung (in der Zeit t nach der Entdehnung). Die -Werte erreichen gewöhnlich vor dem Gipfel der Kontraktur ein Maximum und fallen früher auf Null ab als die absolute Extrakraft. Der Abfall flacht sich mit fallender Konzentration der KCl-Lösung ab. Die aus den -Werten in jedem Zeitpunkt berechneten Geschwindigkeiten der inneren Verkürzung fallen zwar vom ersten Beginn der Kontraktur ab, sind aber auch noch während der Erschlaffung aus der Kontraktur (Entkoppelung) positiv. Aus diesen Befunden kann man schließen, daß die Fähigkeit der Ankoppelung in der ersten Phase der Entkoppelung anhält, aber früher verschwindet als die Kontrakturspannung, sich also unabhängig vom zeitlichen Verlauf der Kontraktur ändert.

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In heart preparations of Aplysia, quick releases during isometric KCl-contractures, evoked by various concentrations of KCl, induce—after the elastic drop in tension—a subsequent rise () in tension (within the time t after the release) above the level of the elastic after effect. Usually the -values reach a maximum before the peak of contracture and decline to zero earlier than absolute extratension. The decline flattens with decreasing concentration of the applied KCl solution. The rate of internal shortening, calculated from the -values at any instant, fall from the very beginning of contracture, but is still positive during the relaxation phase of contracture. From these findings, it may be concluded that the capability of coupeling is still present during the first phase of uncoupeling, but disappears earlier than the tension of contracture, i.e. varies independently of the time-course of contracture.

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Mit 5 Textabbildungen

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Mit Mitteln der Deutschen Forschungsgemeinschaft und ONR.