A comparative study of coagulation effects on the cortex of the rat using Nd-YAG (1.32 μm), Nd-YAG (1.06 μm) and CO2 lasers

This paper represents a comparative study on brain tissue of three lasers: Nd-YAG (1.32m); Nd-YAG (1.06 m); and CO₂ laser. The experimental studies were performed on rats. They consisted of a comparison between the thermal effects and the consequent histological lesions produced. The surface temperature of the cortex induced by each laser shot was measured with an infrared camera. The results show that there exists an excellent correlation between surface temperature and the histology of the lesions produced. It appears that for equivalent surface temperatures the cortical lesions 8 days after irradiation were similar for Nd-YAG (1.32m) and for CO₂ lasers but significantly different for the Nd-YAG (1.06m) laser. For example the depth of coagulation necrosis varied between 20 to 250m with the CO₂ laser using the power of 3 to 10 W at an exposure of 0.05 s with a fluence of 5J/cm² and varied from 210 to 260m using the Nd-YAG (1.32m) with the power of 5 to 14 W with an exposure of 0.4 s with a fluence of 50–170 J/cm². With the Nd-YAG (1.06m) the depth of coagulation necrosis varied from 490m to 550m using a power of 12 to 19 W with an exposure of 0.4 s with a fluence of 150–250 J/cm². It would appear that the Nd-YAG laser at a wavelength of 1.32m should be valuable in neurosurgery as this wavelength is highly absorbed by brain parenchyma and is transmissible with a fibre optic delivery system.

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Résumé Les auteurs presentent une étude comparative de la coagulation du parenchyme cérébral au moyen de différents lasers. Les études expérimentales ont été effectuées sur le cortex du rat. Elles ont consisté à comparer les effets thermiques et histologiques de 3 longueurs d'onde: Nd-YAG (1.32m), Nd-YAG (1.06m) et CO₂ (10.6m). La température corticale de surface induite par le tir laser a été mesurée au moyen d'une caméra infrarouge. Les courbes du profil thermique de chaque tir et de son évolution au cours du temps ont ainsi été obtenues. Les résultats montrent qu'il existe une excellente corrélation entre les données thermiques et les données histologiques recueillies pour chaque tir. Il apparaît ainsi que pour des augmentations de température équivalentes, les lésions corticales 8 jours après le tir sont similaires pour les lasers Nd-YAG (1.32m) et CO₂, mais significativement différentes pour le laser Nd-YAG (1.06m).Par exemple, le profondeur de nécrose varie entre 200 et 250m pour le laser CO₂ utilisé avec une puissance de 3 à 10 W, un temps d'exposition de 0.05 s et une fluence de 5 J/cm². La profondeur de nécrose varie entre 210m et 260m lorsqu'on utilise le laser Nd-YAG (1.32m) avec une puissance de 5 à 14 W, un temps d'exposition de 0.4 s et une fluence de 50 à 170 J/cm². Avec le laser Nd-YAG (1.06m), la profondeur de nécrose est beaucoup plus importante. Elle varie entre 490m et 550m pour une puissance comprise entre 12 et 19 W, un temps d'exposition de 0.4 s et une fluence de 150 à 250 J/cm².Ces résultats expérimentaux montrent que la longueur d'onde 1.32m est bien adaptée à la neurochirurgie puisqu'elle est bien asbsorbée par le parenchyme cérébral et qu'elle est transmissible par une fibre optique.

     

381. Die operative Therapie beim Thoraxtrauma — eine retrospektive Studie

Zusammenfassung Nach multiplem Trauma sinken intracelluläre Aktivität und Konzentration der Elastase in polymorphkernigen Leukocyten (PMNL), die aus Blut ( = 67 U und 6154 g/10⁹ PMNL) und bronchoalveolärer Lavage (BAL)-Flüssigkeit ( = 44 U und 5957 g/10⁹ PMNL) isoliert wurden im Vergleich zu PMNL Gesunder ( = 106 U und 9962 g/10⁹ PMNL). Gleichzeitig wurde ein Anstieg der extracellulären Elastase-Konzentration in Plasma von = 84 g/1 auf = 399 g/1 und in BAL Flüssigkeit von = 8 g/1 auf = 561 g/1 beobachtet. Die durch Stimulation freigesetzte Elastase wird teilweise von einem spezifischen Receptor auf PMNL erneut gebunden. Die Ergebnisse unterstützen die PMNL-vermittelte ARDS-Pathogenese.     

Penetration of cefazolin,ceftriaxone, cefoperazone,and ceftazidime into human gallbladder tissue and bile

Forty patients underwent elective cholecystectomy following administration of a single intravenous dose of cefazolin, ceftriaxone, cefoperazone, or ceftazidime. Mean gallbladder bile concentrations of cefoperazone (398.8 g/ml and ceftriaxone (153.4 g/ml) were significantly higher than those of cefazolin (12.3 g/ml) and ceftazidime (3.08 g/ml) (p<0.008). Mean gallbladder tissue levels of cefazolin (30.1 g/g), ceftriaxone (50.5 g/g), and cefoperazone (91.0 g/g) exceeded that of ceftazidime (7.25 g/g) (p<0.001). When adjusted for known in vitro activity against biliary pathogens, these data suggest that cefoperazone and ceftriaxone are superior to ceftazidime and cefazolin for prophylaxis in elective biliary surgery.

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Resumen Las nuevas cefalosporinas de tercera generación poseen actividad contra una variedad de bacterias, incluso la mayoría de los patógenos biliares comunes. Hemos realizado un estudio prospectivo sobre el grado de penetración de la cefazolina, la ceftriaxona, la cefoperazona, y la ceftazidima en el tejido y la bilis de la vesícula biliar en pacientes sometidos a colecistectomía electiva.Cuarenta pacientes recibieron una dosis única de la cefalosporina dentro de la hora anterior a la colecistectomía. Las concentraciones medias en la bilis de la vesícula biliar fueron significativamente mayores para la cefoperazona (398.8g/ml) y la ceftriaxona (153.4g/ml) que para la cefazolina (12.3g/ml) y la ceftazidima (3.08g/ml) (p<0.008). Los niveles medios en el tejido de la vesícula biliar fueron superiores para la cefalozina (30.1g/g), la ceftriaxona (50.5g/g), y la cefoperazona (91.0g/g que para la ceftazidima (7.25g/g) (p<0.001). Al ajustar estos datos contra valores conocidos de actividad in vitro contra patógenos biliares, aparece que la cefoperazona y la ceftriaxona son superiores a la ceftazidima y la cefazolina en cuanto a profilaxis en cirugía biliar electiva.

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Résumé Quarante patients ont été cholécystectomisés après administration intraveineuse d'une dose unique de céfazoline, de ceftriaxone, de céfapérazone ou de ceftazidine. La concentration moyenne de la bile vésiculaire en céfopérazone (398.8g/ml) et en ceftriaxone (153.4g/ml) était significativement plus élevée que la concentration en céfazoline (12.3g/ml) et en ceftazidine (3.08g/ml) (p<0.008). Les concentrations tissulaires vésiculaires moyennes de céfazoline (30.1g/g), de ceftriaxone (50.5g/g), et de céfopérazone (91.0g/g) étaient plus importantes que la concentration de ceftazidine (7.25g/g) (p<0.001). Lorsque ces antibiotiques sont sensibles in vitro contre des germes pathogènes, nos résultats suggèrent que le céfopérazone et la ceftriaxone sont meilleurs que la ceftazidine et la céfazoline dans la prophylaxie antibiotique de la chirurgie biliaire élective.

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Presented at the Société Internationale de Chirurgie in Sydney, Australia, September, 1987.     

Taxol inhibits osteoclastic bone resorption

Summary We have examined the effect of the anti-tumor compound taxol, on osteoclastic bone resorption. In the bone slice assay, taxol (0.1–0.001 M) dose-dependently inhibited bone resorption with an IC₅₀ of 0.08 M. Osteoclast survival on bone slices was unaffected by 0.01–1 M taxol, but 10 M was cytotoxic. Taxol (1 M) also ihibited osteoclast spreading (45%) on fibronectin-coated slides. The antiproliterative effects of taxol are due to its unique ability to stabilize microtubules. Primary osteoclasts are nonproliferating end cells, so taxol probably inhibits bone resorption by intertering with other microtubule-dependent functions such as cell polarization, motility or vesicle exocytosis. Since these inhibitory effects on osteoclasts in vitro are seen with therapeutically relevant concentrations, taxol therapy may have beneficial side-effects e.g. inhibition of hyperealcemia and bone metastases.     

Sutureless anastomosis of blood vessels using cyanoacrylate adhesives

On the assumption that the remaining suture threads of the anastomotic line play an important role in the progression of anastomotic neointimal hyperplasia, we performed an experimental study on the sutureless anastomosis of blood vessels. An expanded polytetrafluoroethylene graft, 5 mm in diameter and 2 cm in length, was implanted on the abdominal aorta of mongrel adult using one of three methods of anastomosis, namely; a continuous suture, a stay suture, or sutureless anastomosis. Overall patency rates were 83.3 per cent, 91.7 per cent and 75.0 per cent respectively. The thickness of the pannus in the distal anastomotic line after 12 months was 107 m in one graft in the continuous suture group, 106 m and 222 m in 2 grafts each in the stay suture group, and 41 m and 117 m in 2 grafts each in the sutureless group. Because there were cases of patency even after 12 months with a very small pannus thickness, sutureless anastomosis is considered to be a useful method of preventing anastomotic neointimal hyperplasia.     

Pharmacokinetics of methylmethacrylate monomer during total hip replacement in man

Summary The concentration of methylmethacrylate monomer (MMA) in the blood stream after implantation of the components of 15 total hip prostheses using bone cement was determined in the pulmonary artery, the radial artery, and the superior vena cava after cement application, and correlated with the observed drop in blood pressure and the increase in the pulmonary arterial pressure. In all samples MMA was found. The values ranged from 0.02 g/ml to 59 gg/ml. The mean maximum value after implantation of the stem was measured to be 7.8g/ml in the pulmonary artery, 4.6 g/ml in the radial artery, and 1.75 g/ml in the superior vena cava. After implantation of the cup the values were clearly lower. The simultaneously recorded blood pressure decreased slightly during the first 3 min and then returned to previous values. The pulmonary arterial mean pressure increased from 18 to 20mmHg during the first 10 min. Although in some patients a drop in blood pressure started at the same time as MMA reached maximum values, high concentrations did not result in a greater effect on the circulatory parameters. Statistical analysis by the Spearman test revealed no correlation between MMA concentrations and the decrease in blood pressure or the increase in the pulmonary arterial pressure.

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Zusammenfassung Während der Implantation von fünfzehn Totalendoprothesen mit Knochenzement wurden die Konzentrationen von Methylmethacrylatmonomer (MMA) in der Arteria pulmonalis, der Arteria radialis and der Vena cava superior bestimmt und mit dem beobachteten Blutdruckabfall and dem Anstieg des pulmonalarteriellen Druckes korreliert. In den Proben konnten MMA-Konzentrationen zwischen 0,02 g/ml and 59 g/ml nachgewiesen werden. Die mittlere Maximalkonzentration betrug nach Implantation des Schaftes 7,8 g/ml in der Pulmonal-, 4,6 g/ml in der Radialarterie und 1,75 g/ml in der Vena cava superior. Die Konzentrationen nach Implantation der Pfanne waren deutlich geringer. Der gleichzeitig aufgezeichnete Blutdruck fiel geringgradig während der ersten drei Minuten and kehrte dann auf Ausgangswerte zuriick. Der pulmonalarterielle Mitteldruck stieg von 18 auf 20 mm Hg während der ersten zehn Minuten. Obwohl bei einigen Patienten der Blutdruckabfall mit dem Auftreten maximaler MMA-Konzentrationen zusammenfiel, hatten höhere MMA-Konzentrationen keinen größeren Effekt auf die zirkulatorischen Parameter. Bei der statistischen Analyse mit dem Spearman Test bestand keine statistische Korrelation zwischen den MMA-Konzentrationen und dem Abfall des Blutdruckes bzw. dem Anstieg des pulmonalarteriellen Druckes.

     

Metaphyseal aspects of stapling

Summary Blount stapling of the growth plate induced changes in the metaphyseal architecture, which progressed in correlation to the postoperative follow-up. The stereological investigations revealed a subtile reaction of the medial stapled tibial plate in a total of 37 domestic pigs (10 weeks old) during the postoperative follow-up (up to 17 weeks). Zone 1,380–1120 m distal to the plate representing bone modelling, and zone 2, 1180–2360 distally representing bone remodelling, were investigated separately. The findings in zone 2 were very similar to zone 1 but were less extensive. The parameter most sensitive to stapling was the surface density; the trabecular distance showed parallel but less impressive findings. The specific surface and trabecular diameter changed with some delay. The last parameter to change was the volume density.Supported by the Deutsche Forschungsgemeinschaft     

242. Korrelation klinischer und biochemischer Befunde mit dem Schweregrad einer bakteriellen Peritonitis

Zusammenfassung Anhand von Verlaufsdaten 66 chirurgischer Patienten mit einer bakteriologisch gesicherten Peritonitis sollten harte und weiche Kriterien zur Beurteilung des Schweregrades differenziert werden. Untersuchungskriterien: 1) regionale Ausbreitung, 2) Entwicklung eines Organod. Systemversagens, 3) Leukocytose/Thrombopenie, Körpertemperatur, 4) die Plasmamediatoren Endotoxin/Prostaglandin F₂ (PGF₂), 5) Anamnesedauer (Erstsymptom bis OP), 6) Anzahl erforderlicher Reoperationen und 7) Lebensalter. Zuzuordnende Schweregrade: Grad 1: überlebt, Grad 2: mit Komplikationen überlebt, Grad 3: nicht überlebt. Danach erweisen sich als harte Kriterien: 1) Lokalisation, 2) Anamnesedauer, 3) Leukocytose, 4) Endotoxin > 100 Eu/ml, PGF₂ > 500 pg/ml, 5) Körpertemperatur 38,5°C.     

The distribution of extracellular matrix vesicles in healing of rat tibial bone three days after intramedullary injury

Summary The distribution of extracellular matrix vesicles on the third day of bone healing was studied by morphometric analysis of transmission electron micrographs. Detection and grouping of the vesicles was performed according to type, diameter, and distance from the calcified front. The different types were selected as follows: vesicles with electron-lucent contents (empty), vesicles with amorphous electron-opaque contents (amorphic), vesicles containing crystalline depositions (crystal), and vesicles containing crystalline structures with ruptured membranes (rupture). The majority of vesicles were between 0.07 µm and 0.12 m in diameter and were located at less than 3 m from the calcified front. The distribution of the empty, amorphic, crystal, and rupture vesicles was 23.2%, 74%, 2.5%, and 0.3% respectively. Their sequence of arrangement according to diameter was as follows: empty, amorphic, crystal, and rupture, the empty vesicles constituting the smallest and the rupture the largest type. Distances from the calcified front were similar for the empty, amorphic, and crystal vesicles, while the rupture type was located nearest to the front. The present observations support the widely acknowledged hypothesis on the role of extracellular matrix vesicles in mineralization. It is thought that the secretion of empty vesicles from the cell is followed by intravscular accumulation of amorphous Ca and Pi to form a hydroxyapatite crystal that, in turn, ruptures the vesicle's membrane. The maturation process is accompanied by an increase of the vesicular diameter and its approximation to the calcifying front.     

Effects of vitamin D and retinoic acid on human glioblastoma cell lines

Summary The biological significance of vitamin D receptors expressed by glioblastoma and other glial tumours is still unclear. In an effort to clarify this issue we studied the effects of increasing concentrations of 25-dihydroxyvitamin D₃ and its metabolite 1 , 25-dihydroxyvitamin D₃ on two human glioblastoma cell lines. Both substances were capable of inducing a significant (> 50%) reduction in growth of the two glioblastoma cell lines at dosages over 5 M. When the HU 70 cell line was treated by increasing dilutions of 25-dihydroxyvitamin D₃ combined with 1 M all trans-retinoic acid, significant inhibition was apparent even after addition of 25-dihydroxyvitamin D³ in the nanomolar range. Reduction of growth index was mainly due to induced cell death.Our results providein vitro evidence that vitamin D metabolites alone or in combination with retinoids may be potentially useful agents in the differentiation therapy of human malignant gliomas.     

Secretory territories and rate of matrix production of osteoblasts

The secretory territories of rat osteoblasts on the parietal bone were measured directly using scanning electron microscopy. The mean territory of 4620 cells in 19 fields was 154 m² per osteoblast. The range for the fields was 136 to 177 m² per osteoblast. Four hundred cells were measured individually—for these the mean value per osteoblast was 143 m² with a standard deviation of 33. The daily rate of apposition over an 8 day period was 3.12 m (standard deviation 0.22) measured by tetracycline marking of the mineral front. This gave a daily matrix production rate of approximately 470 m³ per osteoblast.

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Zusammenfassung Die Ausscheidungsbereiche von Ratten-Osteoblasten des Scheitelbeines wurden mit dem Raster-Elektronenmikroskop direkt gemessen. Der durchschnittliche Bereich von 4620 Zellen in 19 Gesichtsfeldern war 154 m² per osteoblast. Der Streubereich lag in den verschiedenen Gesichtsfeldern zwischen 136 und 177 m² per Osteoblast. 400 Zellen wurden einzeln gemessen. Bei diesen war der Durchschnittswert per Osteoblast 143 m², mit einer Standard-Abweichung von 33. Die tägliche Anlagerungsrate während einer Periode von 8 Tagen war 3,12 m (Standard-Abweichung 0,22); sie wurde mittels Tetracyclinmarkierung der Mineralisierungsfront gemessen. Dies ergab eine tägliche Produktionsrate der Matrix von etwa 470 m³ per Osteoblast.

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Résumé Les territoires sécrétoires des ostéoblastes d'os pariétal de rats sont déterminées en utilisant la microscopie électronique à balayage. Le territoire moyen de 4.620 cellules, dans 19 territoires, est de 154 m² par ostéoblaste. Les valeurs extrêmes par champ varient de 136 à 177 m² par ostéoblaste. Quatre cent cellules sont mesurées individuellement; la valeur moyenne par ostéoblaste est de 143 m³ avec une déviation standard de 33. Le taux d'apposition journalier, mesuré par la tétracycline pendant 8 jours, est de 3.12 m (déviation standard 0.22). Ce qui correspond à une production matricielle journalière d'environ 470 m³ par ostéoblaste.

     

Renal tubular differentiation in mouse and mouse metanephric culture

Sodium-potassium adenosine triphosphatase (Na-K-ATPase) activity was measured by microassay, and the surface density of basolateral membranes was measured morphometrically in postglomerular segments of single tubules isolated from normally developing, intact mouse kidneys and from transfilter metanephric cultures. Proximal tubule Na-K-ATPase activity was 1092±480 pmol/mm per hour in newborn mice, increasing to 2462±258 in 1-week-old and 3470–578 pmol/mm per hour in adult mice. The Na-K-ATPase activity in newborn mice was approximately one-third of the activity in adult mice. Tubular Na-K-ATPase in transfilter metanephric culture was 972±536 pmol/mm per hour, a mean value almost identical to that in newborn mice. The surface density of basolateral cell membranes was 1.36±0.60 m²/m³ in newborn mice and 1.34±0.45 m²/m³ in 1-week-old mice, increasing to 2.70±0.98 m²/m³ in 4-week-old mice and 2.89±0.51 m²/m³ in adult mice. The surface density of tubular basolateral cell membranes in transfilter metanephric culture was 1.13±0.51 m²/m³, not significantly different from the surface density in newborn mice. The calculated mean surface area of basolateral membranes per unit tubular length was greater in cultures than in newborns, however, because total epithelial volume per unit length was significantly larger in the cultured tubules. Membrane surface area in intact mice increased with age, the surface area per unit length of tubule in adults being 4.6 times the area in newborn animals. The ratio of enzyme activity to membrane surface area more than doubled in the 1st week of life without any increase in the density or surface area of basolateral membranes. The ratio fell thereafter, as membrane area increased with maturation, to a value in the adult animal three-fourths of that in the newborn. The early postnatal increase in enzyme activity, beginning almost immediately after birth, possibly relates to an increased density of enzyme sites on the membrane. The postnatal spurt in enzyme activity, without a corresponding increase in membrane area, suggests that tubules have considerable functional reserve in generating a complement of sodium pumps. The studies of proximal tubules grown in metanephric culture show that the basolateral membranes and the sodium pump are initiated independently of renal blood flow and tubular fluid flow, presumably as inherent characteristics. The functional data confirm the similarity, already shown by morphometric studies, between natural tubules and those grown in culture.     

Effect of second messenger systems on oxalate uptake in renal epithelial cells

The oxalate transport system along with protein phosphorylation appears to be deranged in stone formers. This study was undertaken to characterize in LLC-PK₁ cells in culture the effect of altering specific intracellular second messenger systems on oxalate uptake. Cellular uptake experiments were performed at 37°C in buffer [265 mM mannitol, 5 mM NaOH, 5 mM KOH, 10 mM Ca-EGTA, 25 mM HEPES/TRIS, pH=7.4 or in Hank's balanced salt solution (HBSS)] containing 200 M labeled oxalate (1-¹⁴C, 0.3 Ci). Cells were preincubated with DAG (final concentration of 100 M), phorbol myristate acetate (10 M), forskolin (50 M), 8-bromo-cyclic AMP (50 M), trifluoroperazine (20 M) and low molecular weight heparin (1 mg/ml) for 10 min in the presence and absence of the anion transport inhibitor DIDS (100 M) and the effect(s) on oxalate uptake at 10, 25 and 45 min incubation were determined. Chemicals (DAG, forskolin, TPA and 8-bromo-cAMP) which stimulate protein kinase A or C activity resulted in an increased uptake of oxalate while inhibitors of these systems (trifluoroperazine and low molecular weight heparin) resulted in decreased oxalate uptake. The results dernonstrate that oxalate uptake in renal tubular cells is modulated by protein kinase C and A dependent mechanisms.     

Demonstration of calmodulin-sensitive calcium translocation by isolated osteoclast plasma membrane vesicles

Summary Plasma membrane vesicles were prepared from chicken osteoclasts, and active calcium transport was demonstrated in a spectrofluorimetric assay using the fluorescent calcium concentration indicator, fura-2. Transport activity was inhibited by quercetin (10 M), sodium vanadate (10 M), and the anticalmodulin agents, compound 48/80 (20 and 200 g/ml) and calmidazolium (10 and 20 M). The transport rate (V_max, 1.3 nmol/mg protein/min) was not altered in the presence of the protonophore, nigericin (1 M), indicating that proton transport was not driving calcium transport. Release of accumulated calcium in the vesicles occurred with the addition of bromo-A23187 (5 M) or ionomycin (5 M). Increasing calcium transport occurred with increasing calcium concentration. Finally, the calmodulin content of the vesicles was demonstrated to be 54–134 U/mg protein. These results demonstrate that a calmodulin-sensitive, ATP-dependent calcium transporter is present in the osteoclast plasma membrane.     

Effects of nerve stimulation on the spontaneous action potentials recorded in the proximal renal pelvis of the guinea-pig

The effects of nerve stimulation on the electrical and mechanical activity of the smooth muscle of the proximal renal pelvis of the guinea-pig were investigated using standard tension and microelectrode recording techniques. Spontaneous action potentials were deemed to have been recorded from three cell types. (1) pacemaker cells (9 of >120) had membrane potentials (MPs) of -42.1±2.9 mV and fired action potentials of a simple waveform; (2) driven cells (>100) had more stable MPs of -56.1±1.2 mV (n=36) and more complex ureter-like action potentials; (3) the remaining cells had MPs of -45.5±1.7 mV (n=15) and action potentials with a waveform intermediate to groups (1) and (2). Nifedipine (0.1–1 M) and Cd²⁺ (0.1–1 mM) blocked all spontaneous action potential discharge and depolarized the membrane to near -40 mV. Intramural nerve stimulation (10–50 Hz for 1–10 s) increased both the amplitude and frequency of the spontaneous contractile activity, this increase peaked in about 30 s and decayed slowly over several minutes Nerve stimulation depolarized pacemaker and driven cells 9.1±3.5 (n=3) and 1.6±0.7 (n=6) mV, respectively; the frequency of their action potential discharge increased from 7.6±2.7 and 9.9±1.1/min to 17.3±0.5 and 11.1±1.4/min, respectively. The duration of the action potentials in driven cells also increased significantly for several minutes. All these effects were blocked by tetrodotoxin (TTX) (1.6 M). It was concluded that the positive chronotropic and inotropic effects of nerve stimulation on renal pelvis contractility can be correlated with the changes in the frequency and duration of the action potentials recorded in driven cells.     

Tetracycline double-labeling of iliac trabecular bone in 41 normal adults

Summary A histomorphometric evaluation of the iliac crest trabecular bone remodeling was performed after tetracycline double-labeling in 41 normal Danes (12 males and 29 females) aged 19 to 56 years. The fraction of formative (osteoid covered) and resorptive surfaces was unrelated to age but higher in males than in females (P<0.02 andP<0.05, respectively). The appositional rate (0.65±0.12 m/day) was unrelated to age and sex, whereas the fractional labeled surfaces were higher (P<0.01) in the males (0.18±0.08 m²/m²) than in the females (0.12±0.05 m²/m²), and among the females inversely related to age (R=–0.38,P<0.05). The bone formation rate at BMU level (0.50±0.20 m³/m²/day) was unrelated to sex, but among the females inversely related to age R=–0.49,P<0.01). The bone formation rate at tissue level was higher (P<0.02) in the males (0.13±0.07 m³/m²/day) than in the females (0.07±0.03 m³/m²/day) and among the females inversely correlated to age (R=–0.43,P<0.05). The age- and sex-dependent variations in the dynamic parameters underline the importance of a more elaborated normal material.     

Diffusion theory of isotropic light dosimetry probe response

For the measurements of light energy fluence rate in tissues in vitro and in vivo we have developed an isotropic probe. The response of such a probe depends on the refractive index (n) of the medium. This has been measured in a collimated light beam with the probe in air, water (n=1.33), ehtylene glycol (n=1.43) and glycerin (n=1.46). The response as a function of n has also been calculated using diffusion theory, taking into account reflection at the boundaries. Simple formulas are proposed which very well approximate Fresnel reflection of unpolarized light, facilitating mathematical calculations. For a probe of 3.2 mm diameter with little light absorption the theoretical result depends only on n and differs from the experimental data by not more than 6 %. For a probe of 0.8 mm diameter with some light absorption excellent agreement between theory and experiment could be obtained by adjusting the (unknown) absorption and scattering coefficients ( _a, _s) of the probe material. However, a good fit was only possible within certain limits for _a, i.e. 0.35 mm^–1< _a<0.40 mm^–1, whereas _s (1-g) could be varied between at least 5 and 20 mm^–1 (g is the asymmetry parameter of the scattering function).     

In comparison: 1.064 μm-1.318 μm Nd-YAG continuous wave lasers. In vitro and in vivo experiments for endoscopic tumour therapy in the gastrointestinal tract

In in vitro and animal experiments the tissue effects of the 1.318m Nd-YAG laser were compared to those of the standard 1.064m Nd-YAG laser in order to evaluate the advantages of the new wavelength with a ten times higher absorption in water for gastroenterological tumour treatment. Under irradiation parameters related to clinical endoscopic practice, the laser of the wavelength 1.318m needs for both vaporization and coagulation significantly less energy than the 1.064m laser. Since vaporization at 1.318m is always accompanied by a higher coagulation effect compared to 1.064m the risk of late necrosis and resulting perforation appears to be increased.     

Zinc and magnesium in human seminal plasma

Several hundreds of specimens of human seminal plasma have been analyzed for zinc, magnesium, acid phosphatase activity, cholesterol and fructose. The semen was also analyzed for sperm density, motility, viability and morphology. The mean concentrations of zinc and magnesium were 129 and 106 g per ml, respectively. Zinc and magnesium concentrations were correlated (r=0.84) and both ions appear suitable for evaluation of the secretory activity of the prostate gland. Three out of four semen samples with less than 50 g Zn and/or Mg per ml had pathological spermiograms compared to 40 per cent among those with more than 100 g/ml.Presented at the VIth World Congress on Fertility and Sterility, Tel Aviv, 1968.