Levels of adenosine and adenine nucleotides in slices of rat hippocampus

ATP, ADP, AMP, IMP, adenosine, inosine and cyclic AMP were measured in slices of the rat hippocampus maintained in vitro. Immediately following cutting ATP was low (3.5 +/- 0.6 nmol/mg protein) and AMP high (8.6 +/- 0.9 nmol/mg), giving an energy charge of only 0.34 +/- 0.02. Over the next 90 min the energy charge gradually normalized (to 0.92 +/- 0.01), partly due to conversion of AMP to ATP, but mainly to breakdown to adenosine and other purines which were recovered in the incubation medium. Total purine content decreased from approximately 18 to 10 nmol/mg protein in the first hour following cutting. In slices from old rats the energy charge was lower 60 min following preparation than in younger rats, while cyclic AMP and adenosine levels were higher. The adenosine antagonist 8-phenyl-theophylline tended to enhance the recovery of responsiveness after preparation of the slices. Stimulation of excitatory afferent fibers at a frequency of 10 Hz for 5 min did not significantly alter the purine levels in brain slices, while hypoxia decreased the energy charge significantly and tended to increase adenosine levels. These changes occurred somewhat later than the fall in electrophysiological responsiveness. 8-Phenyl-theophylline was able to delay somewhat the decline in the amplitude of synaptic responses under hypoxic conditions. It is concluded that the viable part of the hippocampal slice, which accounts for about half of the tissue, has levels of adenine nucleotides and adenosine which are similar to those found in the intact rat brain. The return of electrophysiological function following slice preparation is paralleled by a normalization of the energy charge, the adenosine level and the concentration of cyclic AMP. The absence of electrophysiological activity following cutting, and the decreases in such responses following either prolonged afferent stimulation or hypoxia may be related to changes in purine concentration in the slice. Although adenosine accumulating in the slice may contribute to the depression of electrophysiological responses it is probably not the major factor responsible for the reduction in synaptic responsiveness.

Sexual function in prostatic cancer patients treated with radiotherapy, orchiectomy or oestrogens

Sexual function in prostatic carcinoma patients was studied in 12 patients from each of three treatment groups: radiotherapy, orchiectomy and oestrogen treatment. Significant deterioration occurred in all groups. Although erectile potency was preserved in 9 of 12 patients treated with radiotherapy, 7 of these had a marked reduction in the frequency of sexual activity. Men subjected to orchiectomy or oestrogen treatment were seldom capable of having intercourse or of experiencing orgasm. However, oestrogen-treated men continued sexual activity with their partner more often than orchiectomised subjects. Patients receiving oestrogen treatment scored significantly higher for mental depression than those in the other two treatment groups.

Effects of external radiation therapy for cancer of the prostate on the serum concentrations of testosterone, follicle-stimulating hormone, luteinizing hormone and prolactin

Testosterone, luteinizing hormone, follicle-stimulating hormone and prolactin were analyzed in serum from 31 patients with carcinoma of the prostate treated primarily with megavoltage radiation therapy. The total tumor dose varied between 58 and 71 gray (mean 63.5 gray). Absorbed doses to the testes were measured at approximately 1 to more than 10 gray. We investigated retrospectively 17 patients 3 to 60 months (mean 20 months) after therapy and found significantly lower serum testosterone concentrations and significantly higher luteinizing and follicle-stimulating hormone concentrations than in age-matched controls. Of the patients 14 were followed before and after radiation treatment. Testosterone concentrations were reduced significantly 1 week as well as 3 months after treatment but pre-treatment values were found on analysis 6 and 12 months after treatment. The values for luteinizing and follicle-stimulating hormones were significantly higher 3, 6 and 12 months after radiation treatment compared to pre-treatment values. The follicle-stimulating hormone value already increased after 1 week. The greatest observed testosterone alteration occurred 1 week after treatment in patients who received more than 10 gray over the gonads. The use of lead shields protecting the testes reduced the dose absorbed to the gonads by approximately 50 per cent.

Release and uptake of cobalt from cobalt-chromium alloy implants

Cobalt-chromium alloy implants were placed subcutaneously in the neck region of mice, and the animals were killed after 8 weeks. The cobalt concentration was high in the connective tissue of the capsule formed around 5 out of 10 cobalt-chromium implants. In nine other tissues analyzed no statistically significant increases in the cobalt concentration were detected. The surgical procedure and the carrying of an implant did not influence the weight increase of the animals during the period of the experiment.

Effects of inorganic nitrogen on C2H 2 reduction and CO 2 exchange in the Peltigera praetextata-Nostoc and Peltigera aphthosa-Coccomyxa-Nostoc symbioses

Uptake of NH 4 (+) and NO 3 (-) by the N2-fixing lichens Peltigera praetextata (two-component lichen) and P. aphthosa (three-component lichen) was studied. In addition, the effects of these ions, separately and in combination, on C2H2 reduction and CO2 exchange were examined. Both NH 4 (+) and NO 3 (-) were utilized by the lichens. NH4NO3 caused an increased liberation of NO 3 (-) from the lichens as compared to the release observed in untreated lichen thalli. NH 4 (+) and NO 3 (-) led to reduced C2H2 reduction by P. praetextata, which, however, was less pronounced than when the two ions were given in combination. In P. aphthosa the C2H2 reduction was inhibited by NH 4 (+) and NH4NO3, but not by NO 3 (-) alone. NH 4 (+) and NO 3 (-) had no effect on the net photosynthesis of P. praetextata, while, in combination, they led to inhibition, although only at a concentration higher than that inhibitory to the C2H2 reduction of P. aphthosa. The photsynthesis was inhibited by all salts, but only initially, probably a "salt effect". Effects of NH 4 (+) on the membrane potential of the cyanobiont are suggested as an important factor causing the depression of net photosynthesis.

Effect of terbutaline on lung mechanics and morphology in the preterm rabbit neonate

Lung morphology, surface properties of fetal pulmonary fluid, and lung mechanics during spontaneous breathing were studied in preterm newborn rabbits after antenatal administration of terbutaline (0.1 mg). The histological evaluation of lung sections revealed increased amounts of granular eosinophilic and sudanophilic material in the terminal airspaces. The amount of fetal pulmonary fluid was decreased in terbutaline-treated animals; the fetal pulmonary fluid also showed improved surface properties, evaluated by the pulsating bubble technique. Increased dynamic lung compliance without altered air-way resistance was found in terbutaline-treated animals during the first 30 min after onset of breathing. This report demonstrates that terbutaline has an initial beneficial influence on the preterm neonatal lung, probably due to release of preformed surfactant into the alveolar spaces and to dehydration of the lung.

Binding capacity of testosterone-estradiol-binding globulin (TeBG), total and calculated unbound concentrations of testosterone in patients with carcinoma of the prostate treated with orchidectomy or estrogens

Testosterone-estradiol-binding globulin (TeBG) binding capacity, total estradiol-17 beta and total testosterone were measured in patients with carcinoma of the prostate treated with orchidectomy or estrogens. Comparisons were made with a control group. There was a significant increase in TeBG binding capacity in the group treated with estrogens. Both orchidectomy and estrogen-treatment decreased total testosterone significantly and to the same degree. The concentration of free testosterone was calculated using a new method, and was found to be lower in orchidectomized and estrogen treated patients when compared with the control group. When the two groups under treatment were compared, the calculated free testosterone concentration was significantly lower in the estrogen treated group.

Testicular endocrine function after withdrawal of oestrogen treatment in patients with carcinoma of the prostate

The serum concentration of testosterone, luteinising hormone (LH), follicle stimulating hormone (FSH) and prolactin were determined at different intervals after withdrawal of oestrogen treatment in patients with prostatic carcinoma. Oestrogen therapy had been stopped in all patients because of the side effects of oestrogens. There was a negative correlation (r = -0.64) between serum testosterone concentrations and the duration of oestrogen treatment in patients investigated for more than 6 months after withdrawal of hormones. However, the decrease in testosterone concentration seems to be time-dependent. Thus patients who were treated for less than 3 years had normal testosterone concentrations approximately 6 months after withdrawal of the oestrogen therapy. This group of patients had a positive correlation (r = 0.49) between serum testosterone concentration and time elapsed after cessation of therapy. In contrast, patients treated for more than 3 years retained low testosterone concentrations even after 6 months. The other hormones did not vary between the groups. It is concluded that patients with carcinoma of the prostate treated with oestrogens for more than 3 years have an impaired Leydig cell function which might be irreversible.

Effects of GABA and some GABA analogues on respiratory regulation in the preterm rabbit

Preterm neonatal rabbits (gestational age 29 days) were given GABA (750 mg/kg) or the GABA-like drugs muscimol (2 mg/kg) and GHBA (375 mg/kg) intraperitoneally. Basal respiration and the ventilatory response to 10% CO2 were studied, before and after drug administration, in a whole body plethysmograph during halothane anesthesia. The three drugs tested all caused a decrease in minute volume. The decrease in minute volume was mainly due to a decrease in tidal volume after GABA and muscimol, while GHBA reduced minute volume due to a decrease in respiratory frequency. A decrease in respiratory frequency was also seen after muscimol administration. Changes in the respiratory time intervals were seen after muscimol and GHBA both causing significant increases in expiratory and respiratory time. 'Inspiratory drive' and 'respiratory timing mechanisms' were evaluated by VT/TI and TI/TTOT, respectively. GABA and muscimol reduced both VT/TI and TI/TTOT while GHBA only reduced TI/TTOT. Addition of 10% CO2 to the inhalation gas caused an increase in tidal volume and minute volume during control conditions. This response to CO2 was abolished by GABA and GHBA treatment. Our findings demonstrate that GABA and GABA-like drugs cause respiratory depression in the preterm neonate. Central mechanisms are most likely involved in this response. These findings may be relevant to the irregular or apneic breathing sometimes seen in the preterm human infant.

Caries, periodontal and prosthetic findings in patients with removable partial dentures: a ten-year longitudinal study

A 10-year longitudinal study was carried out on 27 patients treated with RPDs. Before the prosthetic treatment all patients were given oral hygiene motivation and instruction as well as periodontal therapy where indicated. The aim was a high level of cooperation. The RPDs, most of which were lower bilateral distal-extension dentures, were carefully planned and designed. During the follow-up period the patients were examined at yearly intervals, at which time remotivation and reinstruction regarding oral hygiene was given, and scaling, operative restorations, and prosthetic and other treatment procedures were preformed as required. Patient cooperation was excellent, and no significant deterioration of the periodontal status of the remaining teeth was found. In addition, there was a low increase in the frequency of decayed and filled tooth surfaces during the decade. The dentures showed damage and several changes during the follow-up period, conditions that necessitated various corrective prosthetic procedures.

Nickel allergy and nickel-containing dental alloys

Test pieces from five cobalt-chromium casting alloys intended for use in removable partial dentures were attached to the skin of 10 women with known allergy to nickel. Patch tests were also performed with nickel and cobalt salts. Nine of the 10 women showed clear-cut or strong patch test reactions to the alloy with 7% nickel, one patient also to one of the other alloys (less than 1% nickel). In five patients with contact allergy reactions to both nickel and cobalt salts mild or marked responses to some of the other alloys were observed. Corresponding observations were made in three out of the five patients with contact allergy reactions to nickel salt but not cobalt salt.

Effects of total and subcapsular orchidectomy on serum concentrations of testosterone and pituitary hormones in patients with carcinoma of the prostate

22 men with carcinoma of the prostate were consecutively subjected to either total or subcapsular orchidectomy at random. Serum concentrations of testosterone, follicle-stimulating hormone, luteinizing hormone, prolactin, thyroid-stimulating hormone and testosterone-estrogen-binding globulin were followed. No differences were found between the two groups during the 6-month follow-up period. Orchidectomy reduced testosterone concentration in all cases and none responded to human chorionic gonadotrophin stimulation 6 months postoperatively. The concentrations of free and bound testosterone were calculated but did not vary between the two types of operation, which were considered equally efficient in reducing testosterone concentration. However, doubts about the completeness of the operation might possibly arise in cases with cancer progress and therefore we prefer total orchidectomy as the first choice, but perform subtotal orchidectomy on those men preferring this type of operation psychologically.

Masticatory efficiency of complete denture patients. A clinical examination of potential changes at the transition from old to new denture

The masticatory efficiency was studied among 19 complete denture wearers with their old and new dentures. The test chewing material was gelatin hardened by formalin. A standardized preparation of the test chewing material and the sieve-system is described. The patients were tested on seven different occasions from the period with the old dentures until about 1.5 years after the insertion of the new dentures. The test pieces were chewed for ten seconds--a practice test--20 seconds and until ready to be swallowed. The chewed material was strained in a sieve-system and masticatory efficiency indices were calculated. The results revealed no statistical significant differences in masticatory efficiency between any of the seven testing occasions with the method used. Thus no significant difference was noticed when patients changed from old to new dentures or during the first 18 months after insertion of new dentures.

Penile blood pressure in erectile impotence following cystectomy

Penile systolic blood pressure and systolic and diastolic brachial blood pressure were measured in 17 men who had undergone cystectomy and prostatectomy for cancer of the bladder. After the operation, 13 patients reported erectile impotence, while 4 retained sexual potency. Comparisons were made with 7 healthy, potent controls. The systolic penile blood pressure was significantly lower and the systolic pressure gradient between brachial and penile pressure was significantly higher in the men with erectile impotence than in the potent men. Reduced penile blood pressure after such operations may arise from vascular trauma. A surgical technique that protects penile blood vessels may conceivably reduce the risk of erectile impotence following cystectomy.

Terbutaline and pulmonary surfactant release in the rabbit fetus

The influence of terbutaline on content of phospholipids and their fatty acid composition in fetal lung wash and lung homogenates was studied in 28-day-old rabbit fetuses. To obtain both the fatty acid composition and the quantity of lecithin and sphingomyelin gas-liquid chromatography (GLC) was used, which gave a linear relationship when compared to standard solutions of the phospholipids. The amount of lecithin was significantly increased in the lung wash in terbutaline-treated fetuses compared to controls, while the sphingomyelin content was unchanged. In the lung homogenates no quantitative differences were noted between the two groups. The fatty acid composition of lecithin and sphingomyelin did not alter neither in lung wash nor in lung homogenate after terbutaline administration. The present results indicate that beta-mimetics mainly act by favouring the release of preformed surfactant and not by stimulating the synthetic capacity of type II cells in the alveolar lining layer.

Appearance of surfaces of dental amalgam in contact with gold. An in vivo study

90 combined gold-amalgam specimens of three dental gold alloys and two amalgams were placed subcutaneously, intraperitoneally and in the cheek pouches of 15 golden hamsters. The appearance of the amalgam surfaces after one week was evaluated using scanning electron microscopy and light microscopy. The results showed that among the implants there was an obvious difference between the conventional amalgam and the non-y2 amalgam specimens as regards accumulation of plaque, which was much more pronounced on the conventional amalgams. The cheek pouch specimens with conventional amalgams differed markedly from the corresponding implant specimens, showing very little plaque accumulation. Some possible explanations for these observations are discussed.

Glyoxylate decreases the oxygen sensitivity of nitrogenase activity and photosynthesis in the cyanobacterium Anabaena cylindrica

Raising the pO2 reduced nitrogenase activity (C2H2 reduction) of Anabaena cylindrica for both glyoxylate-treated (5 mM) and untreated cells. The stimulation caused by glyoxylate, however, increased with increases of pO2 from 2 to 99 kPa. As the pO2 increased the net CO2 fixation was lowered (Warburg effect) while the CO2 compensation point increased. Glyoxylate partly relieved this sensitivity of net photosynthesis to oxygen and reduced the compensation point considerably. The cells used were preincubated in the dark to exhaust photosynthetic pools. A more pronounced reduction in sensitivity of nitrogenase to oxygen for glyoxylate-treated cells was evident when a preincubation in air with reduced pCO2 (13 μl l(-1)) was used. This was, however, not evident until after a 10-h incubation in air. Before this point 2 kPa O2 sustained the highest nitrogenase activity. Addition of 0.5 and 5 mM of HCO 3 (-) to Anabaena cultures preincubated at low CO2 levels (29 μl l(-1)) abolished the stimulatory effect of glyoxylate on the nitrogenase. Thus, the results sustain the suggestion that glyoxylate may act as an inhibitor of photorespiratory activities in cyanobacteria and can be used as a means of increasing their nitrogen and CO2 fixation capacities.

Transient apnea after an enkephalin analogue in the preterm rabbit

FK 33-824, a potent enkephalin analogue was administered systemically, 0.5-5 mg/kg to preterm neonatal rabbits. A marked decrease in respiratory frequency as well as irregular breathing and apneic spells was recorded at 5 mg/kg. Tidal volume was not affected. The enkephalin-induced respiratory depression was restored immediately after naloxone (10 mg/kg). Bases on the results it may be speculated upon whether brain stem enkephalin neurons are involved in the pathogenesis of neonatal transient apnea and irregular breathing.