Electrocardiographic changes in thyrotoxic periodic paralysis.

The electrocardiograms (ECGs) of 30 patients with hypokalaemic thyrotoxic periodic paralysis during and after paralysis were studied. During paralysis, typical features of hypokalaemia were seen in all patients with serum potassium levels of 2.8 mmol/l or less; above this level, the ECGs varied from non-diagnostic to those showing typical features of hypokalaemia. It was not possible to accurately predict the serum potassium level from the ECG except when either sinus arrest or heart block was present. Although extrasystoles have been reported to be common in hypokalaemia, none of the patients in this study had extrasystoles. Sinus arrest occurred in two patients and second degree atrio-ventricular block occurred in three patients, a finding which has not been reported in hypokalaemia.


The effect of pregnancy on the frontal plane QRS axis.

The electrical axis of the heart is an important parameter in electrocardiographic assessment. Slight degrees of left axis deviation have been attributed to a horizontal heart position resulting from the mechanical effects of abdominal distension, such as the physiological event of pregnancy. This study was undertaken to establish the validity of this concept.


Cardiac electrophysiologic effects of etafenone hydrochloride (Dialicor), a new antiarrhythmic agent.

The electrophysiologic effects of etafenone hydrochloride (Dialicor) were studied in isolated rabbit hearts and canine or rabbit cardiac tissues with intracellular microelectrode techniques. The concentration range used was 0.25-10 mg/L, except in experiments with direct addition of etafenone into the tissue bath. Etafenone depressed automaticity in the sinus node, atrioventricular junction and Purkinje fibers at concentrations not affecting the action potential contour. In both atrial and ventricular fibers, etafenone prolonged the action potential duration and total refractory period. The action potential upstroke was slowed and conduction time increased. Higher concentrations reduced the resting potential, causing incomplete depolarization. Atrial action potentials were affected at lower concentrations than ventricular and Purkinje action potentials. Occasi-nally, etafenone produced localized conduction block within the atria, usually sparing internodal conduction. In electrically driven hearts, direct recording of His bundle potential as well as surface electrograms revealed marked prolongation of intraatrial and intranodal conduction times, with some increase in His-Purkinje and ventricular conduction times. Depression of atrioventricular conduction was insignificant under sinus rhythm. Possible therapeutic implications of these electrophysiologic effects are discussed.


Increasing pre-excitation during exercise and isoproterenol infusion. Evidence for a catecholamine sensitive bypass tract.

A patient with atypical chest pain developed pre-excitation during exercise and isoproterenol infusion, with "ischemic" ST depression only during the pre-excited beats. Coronary angiography and myocardial lactate extraction showed no evidence of abnormal coronary vessels. Electrophysiologic study and pacing-induced tachycardia did not induce pre-excitation, whereas exercise induced progressive increase in pre-excitation. The data are consistent with an unusual form of pre-excitation, perhaps related to responsiveness of an accessory bypass tract to catecholamine stimulation. The data also show that the false positive exercise test in this syndrome is due to progressively increasing pre-excitation and therefore more abnormal repolarization.


Treatment of heart block due to sarcoid heart disease.

The role of glucocorticosteroid therapy for myocardial sarcoidosis is not well defined. This report shows the effect of prednisone therapy on atrioventricular (AV) conduction in a patient with myocardial sarcoidosis and AV block. On three separate occasions AV block was documented prior to prednisone therapy. On the first two occasions the patient had first and second degree AV block which by His bundle electrogram initially was shown to be in the AV node. On the third occasion the patient developed complete heart block. On each occasion treatment with prednisone resulted in improved AV conduction. The results indicate that prednisone therapy can be beneficial in the treatment of AV block due to myocardial sarcoidosis.


Congenital complete heart block and long Q-T syndrome requiring ventricular pacing for control of refractory ventricular tachycardia and fibrillation.

A three-year-old girl with congenital complete heart block presented with repeated bouts of ventricular tachycardia and ventricular fibrillation. The ECG was remarkable for both complete heart block and a long Q-T interval, when corrected for rate. The Q-T interval was longer than the Q-T interval of children with congenital complete heart block and of children without heart disease. Overdrive ventricular pacing was necessary to control the arrhythmias. A prolonged Q-T interval in patients with complete heart block, even in the presence of a normal QRS duration, may predispose the patient to sudden death. Permanent pacing can suppress these arrhythmias by overdriving.


Comparison of prolactin levels in human semen and seminal plasma.

Semen samples were collected from 35 men and the levels of prolactin in semen and seminal plasma were measured. There was no significant difference in prolactin concentrations between the two fluids (t = 0.333, P greater than 0.7). There was also no correlation between the prolactin concentration and the kinematic viscosity of the semen (r = 0.065, P greater than 0.7).


Ultradian and circadian rhythms in the plasma concentration of cortisol in sheep.

Three Merino ewes, adapted for about 3 weeks to their environment, were bled at 10 min intervals through a jugular venous cannula. Radioimmunoassay of plasma samples for cortisol revealed marked diurnal variations with peak levels just after midnight and lowest values in the afternoon. This rhythm appeared to result from a changing amplitude associated with a distinct ultradian rhythm (frequency 0.8-1.2 cycles/h) in the plasma level of cortisol. Calculation of the daily rate of secretion of cortisol from the hormone profiles gave a mean value of 8.49 mg. Arguments are put forward in favour of this method for obtaining the true rate of secretion of cortisol.


Effect of storage on the bioactivity of two international reference preparations of human pituitary luteinizing hormone in vitro.

There was no loss of biological activity in vitro when the 1st International Reference Preparation (IRP) for human pituitary gonadotrophins [FSH and LH/interstitial cell stimulating hormone (ICSH) for bioassay] code no. 69/104 and the 1st IRP for human pituitary LH/ICSH [for immunoassay] code no. 68/40 were stored for 1 year at -70 degrees C in a buffered 0.8% saline solution containing 1% bovine plasma albumin (BPA). However, storage of the 69/104 preparation at -20 degrees C in either 0.1 or 1% BPA, or at -70 degrees C in the presence of 0.1% BPA showed a small but significant decrease (approximately 10%) in activity over the same period. It is, therefore, advantageous to store these reference preparations at -70 degrees C in the presence of 1% BPA.


Functional luteolysis in the pseudopregnant rat: effects of prostaglandin F2 alpha and 16-aryloxy prostaglandin F2 alpha in vitro.

The present work concerns the luteolytic effects of prostaglandin (PG) F2 alpha and its analogue, 16-aryloxy PGF2 alpha, upon isolated luteal cells. Varying doses of these two prostaglandins were incubated with cells in the presence or absence of an optimum stimulatory dose of LH (1 microgram/ml). The total contents of progesterone and 20 alpha-dihydroprogesterone in flasks were determined after the incubation periods by radioimmunoassay. Both prostaglandins inhibited basal synthesis of progesterone and 20 alpha-dihydroprogesterone, maximum inhibition occurring at concentrations of either PG of between 250 and 500 ng/ml. In this dose range both prostaglandins were found to abolish LH-stimulated progestogen synthesis completely. These effects were discernible within 5 min of incubation. The studies demonstrated that the onset of PG-induced luteolysis in vitro is characterized by an inhibition of the biosynthesis of both progesterone and its weakly progestogenic metabolite, 20 alpha-dihydroprogesterone; induction of 20 alpha-hydroxysteroid dehydrogenase activity by either PG was not found in incubations extending up to 60 min. In contrast to their relative potencies in vivo, PGF2 alpha and 16-aryloxy PGF2 alpha were essentially equipotent in this in-vitro system.


Androgen receptors in the rat brain, anterior pituitary gland and ventral prostate gland: effects of orchidectomy and ageing.

Available high-affinity binding sites for 5 alpha-dihydrotestosterone (DHT) were measured in cytosols obtained from the amygdala, hypothalamus, anterior pituitary gland and ventral prostate gland of 12-week-old rats at various times after orchidectomy, and in the corresponding tissues of 18-month-old male rats. It is suggested that the lower affinity of the DHT binding reaction in brain and ventral prostatic cytosols after orchidectomy or ageing respectively, may explain, at least in part, the changes in the responsiveness of the tissues to androgens.


Testosterone 5 alpha-reductase activity as related to proliferative status in mouse accessory sex glands.

Testosterone 5 alpha-reductase activity has been measured during the proliferative response of the seminal vesicle and coagulating gland of the castrated mouse after continuous treatment with tesotsterone. Daily subcutaneous injections were begun either 3 or 14 days after castration. At 3 days after castration, a pre-replicative period of 50-60 h occurred before the onset of DNA synthesis, and a continuous [3H]thymidine labelling procedure revealed that only a minority of epithelial cells were subsequently involved in the transitory proliferative response. At 14 days after castration, cells were able to prepare more quickly for DNA synthesis (20-30 h), and the subsequent proliferative response involved a higher proportion of the epithelial cells present. At 14 days after castration, testosterone treatment resulted in the activity of the enzyme/mg homogenate increasing fourfold in the seminal vesicle and tenfold in the coagulating gland, to values almost double those of control (intact animals. At 3 days after castration, testosterone treatment resulted in much slower increases in enzyme activity, and at the completion of day 5 of treatment, levels were close to control values. It is concluded that a relationship may exist between the initial increase in 5 alpha-reductase activity and the duration of the pre-replicative period before DNA synthesis begins. Although testosterone and its resultant effects upon 5 alpha-reductase activity are clearly implicated in the genesis of the proliferative response, the ultimate control of cell proliferation must be independent of androgenic hormones. When cell division was effectively curtailed at the completion of day 4 of testosterone treatment, abnormally high levels of enzyme activity were still present.


Retention of plasma somatomedin activity in the foetal rabbit following decapitation in utero.

One rabbit foetus within each litter was decapitated in utero on day 24 of gestation. Plasma somatomedin activity and costal cartilage metabolism were studied 5 days later in the experimental foetuses and control litter-mates. Somatomedin was assayed by the uptake of [35S]sulphate in vitro into costal cartilage from intact foetuses. Uptake was proportional to logarithmic increases in the concentration of both foetal and maternal rabbit plasma. The mean (+/- 1 S.D.) somatomedin activity of four plasma pools, each pool being derived from the intact foetuses within each of four litters, was 1.3 +/- 0.3 compared with a potency of unity for the reference pool of maternal plasma. The plasma somatomedin activity of decapitated foetuses did not differ significantly from that of control litter-mates when analysed by rank test, but the costal cartilage of decapitated foetuses took up less [35S]-sulphate in basal medium when compared with that of intact litter-mates. The headless body weight of the decapitated foetueses did not rank in a position significantly different from the one expected. The concentration of plasma growth hormone in the decapitated foetuses was less than 5 ng/ml and that of the intact foetuses was more than 157 ng/ml. It is concluded that plasma somatomedin in the rabbit foetus is not dependent on foetal growth hormone.


Specificity of radioimmunoassays for relaxin.

The specificities of two radioimmunoassays (RIA) for relaxin, based upon crude porcine relaxin (NIH-R-P1; RIA I) and a highly purified porcine relaxin (RIA II) have been studied concurrently using purified hormones and plasma samples. A labelled fraction, selected from radio-iodinated NIH-R-P1 and used in that RIA, was also bound to antiserum raised to the highly purified relaxin. Hence a third RIA was possible in which both the crude and the purified relaxins inhibited in the ng/ml range. Porcine insulin and the connecting peptide of porcine proinsulin did not inhibit any of the assay systems whereas porcine proinsulin did inhibit in each assay at the microgram/ml range. Concurrent measurements by assays I and II have been made in sheep plasma obtained during both delivery of the lamb and suckling. The peak values obtained by assays I and II are 3 and 6 min out of phase during suckling and delivery respectively; the NIH-R-P1 relaxin immunoactivity appearing first. The plasma inhibition curves of both appear to be the sum of individual contributions from relaxin and relaxin-like peptides, such as prorelaxin and its fragments, as seen by different antisera. Both assays, however, give qualitatively similar indices of relaxin immunoactivity. The RIA developed for the more purified peptide would be expected to yield a better quantitative estimate of relaxin secretion but this, like specificity, cannot be shown absolutely.


Metabolism of prolactin in mice with a high incidence of mammary tumours: evidence for greater conversion into a non-immunoassayable form.

Monomeric mouse prolactin containing small amounts of 125I-labelled prolactin was administered to adult female mice of a high (C3H/St) and low (C57BL/St) mammary tumour strain. Their endogenous prolactin had been suppressed with 2-bromo-alpha-ergocryptine. The chromatographic profile, on Sephadex G-100, of prolactin in the serum of mice injected with mouse prolactin was compared by direct measurement (radioactivity count) and by radioimmunoassay (RIA) at several intervals after injection. With both methods, the injected hormone was found in the serum in predominantly two molecular sizes, the so-called 'big' and 'little' forms. Although 'little' prolactin in both strains constituted a constant 80% of the total hormone at most intervals by direct measurement, it comprised a comparatively smaller proportion by RIA. In addition, the RIA-determined 'little' prolactin, after reaching maximum levels at 15 min, progressively decreased with time, the decrease being greater in the C3H/St than in the C57BL/St strain. Similar experiments with mouse growth hormone revealed no such discrepancies between the radioactivity counts and the RIA measurements. A fraction of both 'big' and 'little' forms in the C3H/St strain failed to precipitate completely after the material had been incubated with an antiserum to mouse prolactin. These results demonstrate that the prolactin injected into mice is metabolized in serum into two non-immunoreactive forms, one that elutes with the same elution volume on Sephadex G-100 column as the monomer and the other that elutes as the 'big' form. Furthermore, the loss of immunoreactivity of monomeric mouse prolactin is greater in the high-tumour C3H/St strain than in the low-tumour C57BL/St strain. Endogenous immunoreactive prolactin, on the other hand, was found mainly in the 'big' form in the serum of female mice of the C3H/St strain under basal conditions, whereas it was present only in the 'little' form in comparable mice of the C57BL/St strain, even though pituitary extracts of both strains contained mainly the 'little' form. These results support the concept that monomeric prolactin in the systemic circulation of the tumour-prone C3H/St strain is largely in a non-immunoreactive form.


Non-selective inhibition of basal glucagon release by [D-Cys14]-analogues of somatostatin in the rat.

The effects of two [D-Cys14]-analogues of somatostatin on basal plasma levels of glucagon, insulin and glucose were determined in unanaesthetized rats to re-examine a glucagon-selective action of these peptides which has been claimed by others. Somatostatin, [D-Cys14]-somatostatin and [D-Trp8, D-Cys14]-somatostatin caused a short-lasting, dose-dependent decrease of plasma glucagon and insulin but they had no significant influence on plasma glucose. Glucagon and insulin reached the nadir 2 min after intravenous injection of the peptides (dose range 1--10 micrograms/kg) or 5 min after subcutaneous administration (30 and 300 micrograms/kg). At the nadir, insulin was decreased to a greater extent than glucagon and the effecer the nadir and at high doses, the time-course of some effects of the analogues on either glucagon or insulin differed from that of somatostatin. Thus, these [D-Cys14]-analogues may show partial kinetic dissociation of effects on glucagon and insulin but they are not truly selective inhibitors of glucagon release.


Serum levels of the acid-ethanol soluble component of non-suppressible insulin-like activity in untreated and treated streptozotocin-diabetic rats.

Streptozotocin-diabetic rats suffered growth failure and had reduced serum levels of the acid--ethanol soluble component of non-suppressible insulin-like activity (NSILA-S) compared with normal rats. Chronic insulin substitution (6 weeks) resulted in a normalization of serum levels of NSILA-S; this was accompanied by a normal increase in weight. Insulin therapy for 3 days resulted in a partial recovery of serum levels of NSILA-S and a slight but significant accompanying gain in weight. Short-term administration of GH also resulted in a partial recovery of the serum level of NSILA-S, in spite of continued uncontrolled diabetes. These results demonstrate that, in the rat, insulin as well as GH contributes to the regulation of serum levels of NSILA-S.


Conditional discrimination after errorless and trial-and-error training.

Children were trained on a visual discrimination by stimulus shaping, stimulus fading, or trial-and-error. Those who did not acquire the conditional discrimination received a second, different training. More children initially trained by stimulus shaping acquired the conditional discrimination than did those initially trained with stimulus fading or trial-and-error. After a history of fading or trial-and-error training, children were less likely to acquire the conditional discrimination even after the more successful procedure of shaping was later used.


Attention in the pigeon: testing for excitatory and inhibitory control by the weak elements.

In two experiments, pigeons were trained on a successive discrimination between a color and either a compound S+ or a compound S- consisting of a form superimposed on a second color. Two stimulus control tests followed discrimination training: an attention test in which the form and colors used in training were presented singly and in combination, and then a resistance-to-reinforcement test using the form element of S+ or S- and a novel form. In the attention test, the birds trained with a compound S+ responded most to the S+ compound, less to the S+ color alone, and still less to the S+ form on a dark key. Few responses were made to the negative stimulus, either alone or with the S+ form added. The birds trained with a compound S- pecked most at the S+ color and to a compound of the S+ color with the S- form added. The resistance-to-reinforcement test showed that the birds trained with a compound S+ responded more to the S+ form than to a novel form. However, the birds trained with a compound S- did not reliably respond more to a novel form than to the S- form. These findings suggested that the form element of a compound S+ gains some excitatory control, but the form element of a compound S- does not acquire inhibitory control. The possibility existed that low levels of responding to the S+ form on a dark background in the first experiment were due to use of a darkened key to separate S+ and S- periods during discrimination training. However, the essential findings were the same in a second experiment in which darkening of the chamber separated S+ and S- periods.


Reference materials and reference methods in clinical chemistry.

In clinical chemistry today there are often several different methods and instruments in use for the analysis of a particular constituent. When these different methods and instruments are used for careful analysis of the same control specimen, as in assigned value determinations, the assigned values obtained may be significantly different, and these differences may be of clinical importance. In order to determine the reasons for such differences, reference systems or reference points are needed. The reference systems for calibration (calibration materials, standard reference materials) and control (control materials), where the matrices of these different materials must have quite different characteristics, are referred to jointly as reference materials. In order to compare methods, reference methods are needed with known, high reliability. Because of the amount of specimen material needed, the time needed for analysis and the facilities required, reference methods are not suitable for routine analysis. IDeally, standard reference materials are developed first, followed by a definitive method, which is then used to evaluate a candidate reference method. This is currently the case for only a small number of the constituents analyzed in the clinical chemistry laboratory. In this paper the characteristics of the different kinds of reference materials and of reference methods are described. The differences in terminological usage found in the literature are discussed. Limitations of knowledge and technique may necessitate certain compromises, with respect to the ideal characteristics of reference materials and reference methods. Possible compromises are discussed, and the various sources of error associated with them are pointed out. However, these compromises can also lead to improvement in the reliability and comparability of analytical results from different laboratories. As an example of such improvement, the results are presented for assigned value determinations by highly qualified reference laboratories on control specimens for interlaboratory surveys; the decision limits are included and the results are compared with those of the survey participants. Thus various ways are indicated for the use of reference materials and reference methods to improve the reliability and comparability of analytical results, suited to the current state of the art.


A spectrometric version of the total bilirubin determination with the Du Pont ACA with respect to neonatal sera.

A spectrometric modification of the determination of total bilirubin with the Du Pont ACA is described. Accuracy, precision and standardization problems are discussed in comparison with the earlier published diazo modification, as well as other techniques well known in the field of neonatal chemistry.


Determination of oxalate in urine using oxalate oxidase: comparison with oxalate decarboxylase.

The oxalate content of urine is determined by means of oxalate oxidase and simple pH measurement. The enzyme specifically decarboxylates oxalate, producing two moles CO2 per mole oxalate. The CO2 diffuses into an alkaline buffer solution (Hallson, P. C. & Rose, G. A. (1974), Clin. Chim. Acta 55, 29--39) in the closed reaction vessel, and reduces the pH value, which is measured with an electrode. Only 125 microliter native urine is required to measure oxalate concentrations in the range of 80 mumol/l to 1.6 mmol/l (corresponding to 7 to 144 mg anhydrous oxalic acid per liter). The limit of detection is 10 nmol oxalate, and the accuracy is 101% with a coefficient of variation of 6%. The method described is insensitive to various interfering factors, such as reducing and oxidizing substances, cloudy or colored samples. It is therefore also suitable for oxalate determination in food technology and plant breeding.


Esterolytic activity of blood serum in infants with hypertrophic pyloric stenosis.

Esterolytic activity of blood serum was determined in infants with hypertrophic pyloric stenosis and in healthy control children. The substrates hydrolyzed mainly by arylesterase (EC. 3.1.1.2), i.e. p-nitrophenyl esters of acetic, propionic and butyric acid were used. It was found that in infants with hypertrophic pyloric stenosis the rate of p-nitrophenyl propionate hydrolysis was significantly higher than that of the acetate or butyrate. In control group children all three substrates were hydrolysed at similar rates, and these were significantly lower than in infants with hypertrophic pyloric stenosis.


Glucose-6-phosphate dehydrogenase deficiency: biochemical and histochemical studies on hair roots for carrier detection.

Kinetic properties of human hair root glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were studied in order to optimize the assay of these enzymes in lysates from single hair roots. In contrast to previously reported methods, an excess of purified 6-phosphogluconate dehydrogenase was added to the glucose-6-phosphate dehydrogenase reaction mixtures, thus allowing a more exact quantification of glucose-6-phosphate dehydrogenase activity. Although enzyme histochemical techniques suggest a similar distribution of hair root glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, enzyme assays on hair root segments after microdissection nevertheless indicate differences in the distribution of these enzymes. Upon storage a gradual drop in the activity of both hair root enzymes was found, but the rate of decrease in enzyme activity was about equal: the enzyme activity ratio was, therefore, not affected. This opens interesting possibilities for mailing hair roots for screening purposes without any special precautions.


Reduction of sample volume in the SMA 12/60.

A modification of the flow system of the Technicon SMA 12/60 Continuous Flow Analyzer is described. This modification results in a 60% reduction of the sample volume. The sample size required for the analysis of twelve constituents in serum is thereby reduced to only 0.7 ml. This modification is simple and does not require complex hardware. The reduction in sample size also leads to a considerable cost reduction (25%).


Aldehyde dehydrogenase of the Mongolian gerbil, Meriones unguiculatus.

The aldehyde dehydrogenase (Aldehyde:NAD(P) oxidoreductase E.C. 1.2.1.3. and 1.2.1.5) phenotype in several tissues of the Mongolian gerbil, Meriones unguiculatus, has been established. The tissue distribution of gerbil aldehyde dehydrogenase is similar to that of the rat, with liver possessing the majority of the aldehyde dehydrognease activity. Male kidney and testis possess significantly more activity than female kidney and ovary. The substrate and co-enzyme specificity of gerbil liver aldehyde dehydrogenase is also similar to that of rat and mouse liver. Gel isoelectric focusing resolves one major gerbil liver aldehyde dehydrogenase isozyme at pI 5.3. Mouse liver is resolved into two major isozymes at pIs 5.3 and 5.6 and rat liver aldehyde dehydrogenase into one major isozyme at pI 5.4. Gerbil liver aldehyde dehydrogenase is functional over a broad pH range with an optima at pH 9.0. Rat and mouse liver aldehyde dehydrogenase possess sharp pH optima at pH 8.5.


Developmental changes in the pyruvate kinase isozymes of coho salmon.

Pyruvate kinase exists as two major isozymes in coho salmon. As in mammals and birds, one form is present in the early embryo and maintains a wide tissue distribution in adults. This salmonid type K shows anodal migration during electrophoresis at pH 7.5. The appearence of functional musculature in the developing embryos. In adult animals this second form is the only pyruvate kinase in muscle. Brain, kidney, liver and gill contain primarily the type K pyruvate kinase while heart contains both major forms along with three intermediate forms which presumably constitute a hybrid set. Since there is no additional isozyme restricted to gluconeogenic tissues, we conclude that a type L isozyme has not developed in these animals. The two major isozymes are immunologically distincy. Both forms are dubject to fructose 1,6-bisphosphate activation of phosphoenolpyruvate binding, but the magnitude of the effect is small. The affinities for phosphoenolpyruvate are similar, but salmon type K has hyperbolic saturation curves with this substrate and type M has sigmoidal saturation curves. While the immunological data indicates considerable divergence in structure, the kinetic parameters of the two forms have remained relatively similar.


Stomatogenesis during sexual and asexual reproduction in an amicronucleate strain of Paramecium caudatum.

Amicronucleate cells of Paramecium caudatum, whose micronuclei have been artifically removed by micropipetting, are characterized by the appearance of a deciliated area at the posterior part of the buccal opening. These cells form food vacuoles at a slightly lower rate than micronucleate cells. Their mean interfission time is longer than that in micronucleates. The exconjugants of amicronucleate cells can not form food vacuoles and eventually die witout fission, though conjugation proceeds normally in them as well as in their micronucleate mate. The oral apparatus of amicronucleate exconjugants seems to be shallower than that of micronucleates. The membranellar cilia, therefore, can be seen through the buccal overture by scanning electron microscope. The results obtained from the cross of micronucleate and amicronucleate strains and from the induction of autogamy in amicronucleate strains suggest that the micronucleus has a primary role in developing the normal oral apparatus after nuclear reorganization.


HCO3-stimulated Cl efflux in the gulf toadfish acclimated to sea water.

Unidirectional efflux of Cl was examined in the Gulf toadfish, Opsanus beta, in artificial seawater solutions with modified concentrations of Cl and HCO3. Removal of Cl HCO3 reduced Cl efflux. Addition of HCO3 at typical seawater concentrations stimulated Cl efflux, independent of changes in the transepithelial potential. This active, HCO3-stimulated Cl efflux is saturable, with a Km of 2.4 mM, typical of the concentration of HCO3 found in sea water, and independent of external pH. Active extrusion of Cl offsets the net diffusional and oral gain of Cl faced by O. beta in sea water.


In vitro development of core cells of the inner cell mass of the mouse blastocyst: effects of conditioned medium.

Blastocysts submitted to two rounds of immunosurgery give rise to cores of presumptive ectoderm cells, many of which do not survive for more than 48 hours when cultured individually. Precoating of the culture plates with conditioned medium (CM) from PYS-2 cells increases the incidence with which cores regenerate an outer layer. This procedure also improves the survival frequency of the cores, but only for a limited period of time. The small number of cores which survive for two weeks or more, either in uncoated or CM-coated plates, give rise to any array of cell types, including giant cells resembling trophoblast.


In vitro synthesis of RNA by Xenopus spermatogenic cells I. Evidence for polyadenylated and non-polyadenylated RNA synthesis in different cell populations.

Premeiotic and postmeiotic (haploid) gene expression during spermatogenesis in the anuran, Xenopus laevis, was studied by analyzing the accumulation of radioactively labelled cytoplasmic polyadenylated [poly (A +)] and non-polyadenylated [poly (A -)] RNAs. Dissociated spermatogenic cells were labelled and maintained in an in vitro system capable of supporting cell differentiation. Labelled cells were separated by density gradient centrifugation into subpopulations enriched for individual spermatogenic stages. RNA was extracted and purified from each cell fraction, and separated into poly (A +) and poly (A -) species. Comparison of poly (A +) to non-poly (A) radioactivity in cells labelled with tritiated uridine or adenosine demonstrated that (1) all cell fractions produced significant quantities of polyadenylated RNA relative to total RNA synthesis; and (2) that a cell fraction enriched for pachytene spermatocyte RNA contained up to 15% of total cytoplasmic and 35% of total polysomal RNA labelled as poly (A +) containing species. RNA was also characterized by sucrose density gradient centrifugation and polyacrylamide gel electrophoresis. All cell types showed typical poly (A -) peaks of 4S, 18S and 28S, corresponding to tRNA (4S) and rRNAs (18, 28S) respectively. Spermatids and spermatozoa had additional absorbance peaks at 13 and 21S which cosedimented with Xenopus oocyte mitochondrial rRNA. Patterns of incorporation of uridine and adenosine into poly (A +) RNA in all germ cell fractions tested were complex. In all cases, major areas of radioactivity were found in a broad band sedimenting between 6-17S. Spermatid fractions showed a prominent peak of incorporation at 6-8S, while pachytene cells also showed heavier poly (A +) peaks in the 17-25S region. A non-polyadenylated RNA species sedimenting at 6-8S with a relatively rapid rate of turnover was also observed in spermatids. From these results it is concluded that synthesis of transfer, ribosomal, and putative messenger RNA species continues in spermatogenic cells throughout all but the very last stages of spermatogenesis in Xenopus.


Solute compatibility with enzyme function and structure: rationales for the selection of osmotic agents and end-products of anaerobic metabolism in marine invertebrates.

The major nitrogenous osmolytes present in the cells of marine invertebrates, notably the free amino acids glycine, alanine and proline, and trimethylamine oxide and betaine, are highly compatible with proper enzyme function and structure. These nitrogenous osmolytes display either non-perturbing or, in some cases, favorable effects on enzyme-substrate and enzyme-cofactor complex formation, catalytic velocity and protein structural stability. In contrast, inorganic salts (KCl and NaCl) and certain of the free amino acids which play only a minor osmotic role, e.g., arginine and lysine, have strongly perturbing effects on one or more of these enzymic parameters. The compatible nitrogenous solutes therefore are suitable for use at high (several tenths molar) concentrations and at widely varying concentrations in osmo-conforming species. Certain nitrogenous solutes, especially trimethylamine oxide, betaine and glutamate, offset some of the perturbing effects of inorganic ions on enzyme function. The selective accumulation of osmolytes thus involves not only the concentration of non-perturbing solutes, but also a balanced accumulation of solutes with opposing effects on enzymes. The selection of end-products of anaerobic metabolism also appears to be based, in part, on considerations of solute compatibility with enzyme function. Octopine is a non-perturbing solute, whereas arginine, which is condensed with pyruvate to form octopine, is very strongly perturbing. Succinate has marked stabilizing effects on protein structure. We conclude that the composition of the intracellular fluids of marine invertebrates reflects selection for osmolytes and end-products whose net effects create a cellular microenvironment which is conducive to optimal enzyme function and structure. The accumulation of compatible solutes may preclude the necessity for widespread changes in protein structure in adapting to concentrated or highly variable osmotic environments.


Distribution of phenylalanine hydroxylase (EC 1.14.3.1) in liver and kidney of vertebrates.

The range of phenylalanine hydroxylase activity was determined by measuring the conversion of radioactive phenylalanine to tyrosine in liver and kidney of various vertebrates. Rodents (rats, mouse, gerbil, hamster and guinea pig) were found to have the highest liver phenylalanine hydroxylase activity among all animals studied. They are also the only species that possessed a significant kidney phenylalanine hydroxylase activity which was about 25% of that found in the liver of the same animal. The synthetic dimethyl-tetrahydro-pteridine, used as a cofactor for the enzyme assay in most studies, catalyzed non-enzymatic hydroxylation of phenylalanine to tyrosine. Inclusion of boiled-blank and strict control of timing between incubation and product measurement were essential precautions to minimize erroneous results from substrate contamination and non-enzymatic hydroxylation.


Autoradiographic and electron microscopic studies of minced cardiac muscle regeneration in the adult newt, notophthalmus viridescens.

The regenerative response of minced cardiac muscle grafts in the adult newt was studied using autoradiography and electron microscopy. One-sixteenth to one-eighth of the newt ventricle was amputated, minced, and returned to the wounded ventricle. At five days after grafting, no reorganization of graft msucle pieces was apparent and there was degeneration of much of the muscle graft. Another, smaller population of 5-day myocytes had euchromatic nuclei and intact sarcolemmae. In 10- and 16-day grafts, continuity between ventricular and graft lumina was established and coalescence of graft pieces was apparent. Ultrastructurally, 10- and 16-day graft myocytes appeared to have fewer myofibrillae and increased amounts of rough endoplasmic reticulum, polyribosomes, Golig complexes, and dense bodies when compared to uninjured ventricular myocytes. The peak of proliferative activity of graft cells was observed at 16 days. Electron microscopic autoradiography revealed breadkdown of myofibrillar structure in labeled myocytes, whereas in myocytes in the later stages of mitosis only scattered myofilaments and no Z bands were present. By 30 days, grafts appeared as an integrated structure composed primarily of cardiac muscle. Myocytes of 30-day grafts were observed in various stages of myofibrillogenesis and contained numberous 10-nm filaments. Seventy-day graft mycoytes had numberous well organized myofibrillae and intercellular junctions similar to those seen in uninjured ventricular myocytes.


Abnormal scale morphogenesis: relationship of polypeptide patterns to action of the scaleless gene.

The polyacrylamide gradient gel electrophoresis (PAGGE) pattern of polypeptides isolated from normal scuttate scale epidermis of 1-week-old chicks was different from that of the anterior shank epidermis from 1-week-old scaleless mutant chicks. The PAGGE patterns of polypeptides isolated from normal and scaleless reticulate scale epidermis (from 1-week-old chicks) differed by only one band, whereas comparison of mutant's scuttate and reticulate patterns showed three band differences. These data are discussed in relation to the action of the scaleless gene on early morphogenesis of the two types of scales.


Effects of accelerating stimulation on different indices of development in Japanese quail embryos.

Effects of continuous accelerating stimulation on the timing, duration and rate of occurrence of different indices of development in Japanese quail embryos were examined. Indices used were: the onset of breathing and hatching, also pipping, clicking, vocalisation, membrane penetration, yolk sac withdrawal and lung aeration. Results showed that embryos stimulated by clicks began breathing about nine hours in advance of unstimulated controls and hatched about 23 hours in advance. All other indices occurred early in comparison with controls but not all occurred at the same accelerated rate and some having begun early, proceeded at the same rate as controls then were completed rapidly just before hatching. Developmental problems are discussed in the light of these results and it is suggested that continuous accelerating stimulation affects development in two main stages.


Epidermal-dermal recombinations with embryonic naked and normal back skin of Gallus domesticus.

Birds exhibiting a varying featherless condition resulting from the recessive sex-linked gene naked (n) were used to investigate whether the gene altered the dermis or the epidermis. By splitting 7-day normal and naked skin into its dermal and epidermal components, and heterotypically recombining and growing it in chambers on the chorio-allantoic membrane (CAM), it was found that the epidermis of the naked birds is the site of mutant gene action. A histological study of developing normal and naked skin was done and the structure of the naked feather is elucidated.


Intermediate filaments connect z-discs in adult chicken muscle.

When adult chicken skeletal myofibrils are treated with a myosin-extracting solution, the Z-discs with attached actin filaments retain their linear connections with one another in the extracted myofibril. The sarcomere length increases in the extracted myofibrils from a control lenght of 2.5 micrometer up to 6 micrometer. In a sarcomere, eight to fifty 10 nm filaments can be seen in parallel array in the H-zone. The 10 nm-wide filaments do not bind heavy meromyosin and are two to four micrometers in length. These intermediate filaments are postulated to be an integral part of the sarcomere, connecting Z-bands along the length of the myofibril.


Relationships among different stages of Piagetian tasks and spatial relations in adolescents.

High school students aged 15 through 19 years (N = 116) were administered three Piagetian type tasks (conservation of weight, paper and pencil tests of concrete-operational reasoning and formal-operational reasoning) and a measure of spatial relations (the Revised Minnesota Paper Form Board Test). While a path analysis showed there were logically expected relationships among the tasks, neither sex differences nor age differences were found on any of the measures.


Memorizing and copying visual patterns: a Piagetian interpretation.

Six-, 8-, 10-, and 12-year-old children (10 boys and 10 girls) reconstructed two visual patterns from immediate memory, while other 5- and 6-year-old children (10 boys and 10 girls) reconstructed the identical patterns by direct copying. Patterns were simple and composed entirely of circles or squares as component items. Four results were emphasized: (a) Numerous errors mady by the copying groups led to the conclusion that memory loss is often overestimated in young children. Since an independent estimate of perceptual encoding errors is rarely carried out, encoding mistakes are often included among forgetting errors. (b) One pattern was both copied and remembered more poorly than the other in accord with a Piagetian interpretation of a conceptual conflict inherent in the pattern design between spatial and numerical correspondence of component pattern items. (c) A memory strategy emphasizing configuration preservation was suggested for the 6-year-olds who made slightly fewer memory than copying errors for two configural scoring categories. (d) Performance in an unrelated planning-for-memory task significantly differentiated between better and worse performers on the visual pattern memory task.


Geometric problem solving related to differences in sex and mathematical interests.

Sex differences in Einstellung Effects were confounded by attitudinal factors. Hypothesizing that this was the case for spatial visualization and restructurization, we compared male and female college students' solutions of three elementary geometric problems. Used by Max Wertheimer to study productive thinking, they call for a Gestalt, spatial approach. In group administration to 86 calculus students, males did somewhat better than females, but the reverse held in classes where most women majored in mathematics. Individual administration to 200 Ss, balanced for sex and major, showed that female mathematics majors had more solutions than other females: e.g., 51 percent more compared to 26 percent sex differences. Four hints were available for restructuring each problem. The percentage needing all four hints was highest for male nonmathematics major and next highest for female mathematics majors (e.g., 75 and 23 percent, respectively). Embarrassment at needing hints in such "easy problems" and ego-involvement were factors. Thus, sex differences were less pronounced than differences related to mathematical abilities and interests and to task-and ego-concerns.


Sex differences in the association of cerebral hemispheric specialization of spatial function with conservation task performance.

The association of locus of cerebral hemispheric specialization of spatial function with identity and equivalence conservation judgments was tested in a group of 4- to 6-year-old right-handed children (N = 31). Separate multiple regression analyses for males and females revealed that locus of specialization of spatial function was irrelevant for performance on the equivalence conservation task but was a significant factor in male identity conservation performance. Whereas right hemisphere specialization was advantageous for males, it was of no significant import for females. Results are discussed in the light of previous research on the use of differing cognitive stratergies by males and females in problem-solving situations.


Neurobiology, culture, and behavior disturbances. An integrative review.

The study of the influence of culture on behavior disturbances has a long history in psychiatry. Attention has principally focused on etiological questions and on how psychiatric illness is handled socially, although there is a tradition which deals with the manifestations of so-called functional psychiatric illnesses. In all of these instances, the methods and rationale of the social sciences have been employed and underlying neurobiological factors neglected. However, since a people's culture is learned, it is obviously internalized in some way in the individual. A basic question is how cultural influences may possibly affect the organization and functioning of the nervous system and, by extension, behavior and its disturbances. The relevance of this topic for psychiatry and the social sciences is illustrated by analysis of four prototypical organic psychiatric illnesses.


Why should dialysis benefit schizophrenia?

If dialysis is successful for the treatment of schizophrenia, the artificial kidney must be removing something which the human kidney cannot, unless other nonspecific factors are involved. Either there is an abnormal compound present which is retained by normal renal tubular transport processes, or the kidney of a schizophrenic must be abnormal in that it fails to excrete a normally present compound. Since the latter explanation is less probable, biochemical research should focus on classes of compounds which are known to be handled differently by the artificial kidney than by the human kidney. A dialyzable "schizophrenic toxin" might be a nonprotein, nonprotein-bound of molecular weight below 500 daltons such as an organic acid or base. Proteins, peptides, amino acids, and trace elements are less likely possibilities.


Premorbid social competence and outcome among schizophrenic and nonschizophrenic patients.

The relation between premorbid social competence and outcome was examined with 381 male state hospital patients in four diagnostic categories: schizophrenia, affective reaction, psychoneurotic disorder, and personality disorder. Outcome was assessed using the measures of length of initial hospitalization, total length of rehospitalization, and number of readmissions. The follow-up period was 3 years after discharge from the first hospitalization. On all outcome measures, higher social competence was significantly related to favorable outcome. The four diagnostic groups differed significantly in social competence level, but no evidence was found to indicate that the social competence-outcome relation was influenced by diagnosis. Results were interpreted as consistent with a developmental formulation and as indicating that the relation between premorbid social competence and outcome is not unique to schizophrenia but obtains over a broad range of diagnoses.


A study of schizophrenics' ability to localize the source of a sound.

Twelve process, nonparanoid schizophrenics, 12 nonschizophrenic psychiatric controls, and 12 normal controls were given an auditory localization task. Performance was measured by the number of correct localizations and was studied as a function of three variables: diagnosis, position of the apparatus in relation to the subject's median plane (right or left), and the degree of displacement of the auditory stimulus from a fixation point (4.5 degrees, 3.0 degrees, and 1.5 degrees). A three-way analysis of variance with two repeated measures resulted in a significant main effect for each of the three independent variables. Orthogonal comparisons indicated no difference in performance between normal and psychiatric controls but a significant difference between schizophrenics and the combined controls. The degree of displacement of the auditory stimulus resulted in a significant linear trend in performance. There were no significant interactions. The present findings strongly suggest that process, nonparanoid schizophrenics suffer from a specific deficit in auditory localization.


The elicitation of visual hallucinations via brief instructions in a normal sample.

College students tested in groups were given brief suggestions either to "see" or to "imagine" a kitten. Subjects responded twice, once with eyes open and once with eyes closed. They rated the duration, transparency, and vividness of their imagery, and also their involvement in and belief in the reality of their imaginings under both eye closure conditions. "Imagine" suggestions elicited imagery of longer duration than "see" suggestions. Although subjects reported longer, more vivid, and less transparent imagery with their eyes closed, this effect was dependent on the order of eye closure (i.e., whether the eyes closed instruction preceded or followed the eyes open instruction). The three dimensions of imagery intercorrelated, and each dimension also correlated with subjects' degree of involvement in and belief in their imaginings. A minority of subjects given both the "see" and "imagine" suggestions reported believing that their imaginings were real events during the suggestion period. Furthermore, belief in imaginings was the only variable that correlated with hypnotic susceptibility. These data indicate that hallucinations (i.e., believed-in imaginings) can be elicited from a minority of "norman" subjects with brief instructions.


Mood changes and flooding outcome in obsessive-compulsive patients. Report of a 2-year follow-up.

Twenty-five chronic obsessive-compulsive patients treated with flooding were investiaged retrospectively after 2 years by an independent assessor for the presence of depressive mood fluctuations during their life histories using a five-point rating scale. Patients themselves also completed rating scales for obsessional phenomena during the pre-, post-treatment, and follow-up assessment. Fifteen patients were characterized as not having exhibited mood changes and 10 as having such changes. Patients without changes responded promptly to flooding treatment and showed further improvement during follow-up. Patients with mood changes, although responding well to initially delivered flooding sessions, showed significant relapse at follow-up.


Sleep induced by L-tryptophan. Effect of dosages within the normal dietary intake.

Previous results have demonstrated sleep-inducing effects of L-tryptophan in doses of 1 to 15 g at bedtime. The present laboratory study extends the dose-response curve downward, comparing doses of 1/4 g, 1/2 g, and 1 g of L-tryptophan with placebo, in 15 mild insomniacs (subjects who reported sleep latencies of over 30 minutes). One gram of L-tryptophan significantly reduced sleep latency: the lower doses produced a trend in the same direction. Stage IV sleep was significantly increased by 1/4 g of L-tryptophan. These results at low doses have interesting implications since the normal dietary intake of L-tryptophan is 1/2 g to 2 g per day.


Recurrent pathological jealousy.

A 36-year-old man suffered from pathological jealousy during three marriages. The episodes involving delusions of infidelity were usually preceded by premonitory symptoms. At first, the patient responded by discontinuing his medication (a phenothiazine) so that he might remain vigilant. Later he came to recognize the premonitory symptoms as signals indicating a need for help, and he would request hospitalization. In the periods between his marriages he was never troubled by feelings of jealousy. The chief determinant of delusions of infidelity in this instance, as in three reported by Docherty and Ellis, seemed to be exposure to the mother's extramarital sexual relations. This case, in which three different wives were subjected to the same pattern of behavior, would seem to be an exception to the rule that if marital problems occur both partners are responsible for creating them.


Hysterical sleep episodes as a manifestation of masked depression.

A 55-year-old man suffered from compulsive sleep episodes as a manifestation of masked depression. Although the overt symptoms were conversive in nature, the treatment which finally focused on the depression was followed by disappearance of the patient's recurring sleeping spells for the first time in 4 years. Three methods were used: a) supportive psychotherapy, b) behavior therapy, and c) antidepressive medication. We conclude that the behavior treatment indirectly revealed the masked depression previously concealed by rigid defense mechanisms.


An anticholinergic toxicity reaction to chlorpromazine activated by psychological stress.

A 42-year-old woman with a long-standing diagnosis of schizophrenia experienced two toxic reactions to 1200 mg of chlorpromazine while awaiting surgery for a locally metastatic carcinoma of the cervix. These reactions, which involved fever, increased pulse and respirations, and acute onset of obtundation, and which cleared after several hours, were produced by a medication and dose which had been well tolerated prior to the preoperative period. These reactions, typical of an acute anticholinergic syndrome, were precipitated by an interaction of the drug and a stress-induced change in her psychological state, due to anxiety about her cancer and impending surgery. This type of reaction has not been reported previously in a clinical setting.


Conformational influences on brain tryptophan hydroxylase by submicromolar calcium: opposite effects of equimolar lithium.

Tryptophan hydroxylase from rat midbrain, EGTA-pretreated and dialyzed, manifested allosteric properties with respect to its substrate tryptophan, cofactor tetrahydrobiopterin, and the calcium ion. Kinetic studies suggest two preferred enzyme conformations in the presence of low concentrations of the cosubstrates: a higher affinity form manifesting hyperbolic substrate kinetics, induced by submicromolar (0.4--0.8 microM) calcium in vitro and cocaine in vivo, and a lower affinity form exaggerating cooperativity with respect to substrate, induced by submicromolar (0.4 to 0.8 microM) lithium in vitro and lithium in vivo. Lithium's effect on serotonin biosynthesis may be due to its antagonism of the positive effector influence of calcium on tryptophan hydroxylase, either as a negative effector or by blocking the calcium site.


Secretory activity and histoenzymological characteristics in the subcommissural organ of hormone-injected ducks, Anas platyrhynchos.

Gonadotrophin and gonadal hormone injections performed on male ducks induce some changes in the activity of the subcommissural organ (SCO). Particularly LH, FSH and testosterone propionate injections are followed by a depletion of secretory material accompanied by increased activities of investigated dehydrogenases and acid phosphatase in SCO cells.


Location by paper chromatography of compensatory ovarian hypertrophy (COH) inhibiting activity in isobutanol extracts of bovine pineals.

Bovine pineal glands were extracted according to the methods reported by Bensinger et al. (1973) and Cheesman and Fariss (1970). Isobutanol soluble COH-inhibiting activity was further separated by chromatography on Sephadex G-15 and paper chromatography. With the Bensinger method, different active pineal fractions were obtained from Sephadex G-15 columns. Certain of those fractions were further separated by paper chromatography in butanol : acetic acid : water (4 : 1 : 1) and the COH-inhibitor was localized. The pineal COH-inhibitor could also be localized by high pressure, reverse phase liquid chromatography. More COH-inhibiting activity was extracted with the Bensinger method than with aqueous and acetic acid extraction methods used earlier by us. The Cheesman extraction method for arginine vasotocin gave less regular results in our hands than the Bensinger extraction method.


Dietary management of nystagmus.

Two case reports illustrate the therapeutic response of congenital nystagmus to a diet eliminating synthetic food colors, synthetic food flavors, the antioxidant preservatives butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), and a small group of foods thought to contain a natural salicylate radical. A brief discussion of the hyperkinetic syndrome is offered with the proposal that a variety of neurologic and neuromuscular disturbances (grand mal, petit mal, psychomotor seizures; La Tourette syndrome; autism; retardation; the behevioral component of Down's syndrome; and oculomotor disturbances) may be induced by identical chemicals, depending upon the individual's genetic profile and the interaction with other environmental factors. It is perhaps the failure to integrate all the signs presented by the various clinical patterns with hyperkinesis or Minimal Brain Dysfunction (MBD) under a single heading that eye muscle involvement manifested as either nystagmus or strabismus has not been emphasized as part of the hyperkinetic syndrome.


Effects of intranigral administration of dopamine agonists and antagonists and baclofen on concentrations of dopac and dopamine in the striatum and substantia nigra of the rat.

Systemic administration of haloperidol to rats failed to alter the concentration of dopamine but increased the concentration of 3,4-dihydroxy-phenylacetic acid (DOPAC), the major metabolite of dopamine, in both the striatum and substantia nigra. These haloperidol-induced changes in DOPAC were prevented by an intranigral microinjection of baclofen, a drug which reduces nigrostriatal dopaminergic neuronal activity. It has been proposed that nigrostriatal neurons are regulated, in part, by the activation of autoreceptors in substantia nigra. However, intranigral microinjections of high concentrations of several dopaminergic antagonists failed to mimic the biochemical effects resulting from systemic administration of these drugs; instead, they slightly increased the concentrations of both dopamine and DOPAC in the striatum and decreased dopamine in substantia nigra. Intranigral microinjections of the dopamine agonist, apomorphine, failed to alter the concentration of DOPAC in the striatum, but reduced both dopamine and DOPAC in the nigra. If DOPAC concentrations reflect nigrostriatal dopaminergic neuronal activity, the present results suggest that dopaminergic agonists and antagonists acting in substantia nigra do not exert a major influence on the activity of these neurons.


Effect of quipazine on brain stem monoamine neurons histofluorescence studies.

Using two fluorescence histochemical methods, formaldehyde-induced fluorescence and sucrose-potassiumphosphate-glyoxylic acid fluorescence (SPG), we studied the effect of 5-hydroxytryptamine receptor stimulation by quipazine (2-[-piperazinyl]quinoline maleate) on monoamine fluorescence in the brain stem of rats. It was found that quipazine in a dose of 5 mg/kg i.p., after 60 min, decreased noradrenaline fluorescence intensity in noradrenergic neurons of the subcoeruleus area and diminished th density of catecholamine terminals visualized in the central part of the dorsal raphé nucleus. In the principal locus coeruleus, the intensity of fluorescence in nerve cells was not changed using either method, but with the SPG procedure, diffuse fluorescence outside cell bodies was observed after quipazine. In dorsal raphé neurons, a slight increase in 5-hydroxytryptamine fluorescence intensity was observed. The results obtained indicate that quipazine, apart from its effect on 5-hydroxytryptamine neurons, may also affect certain noradrenergic neurons.


The synaptic ribbons of the guinea pig pineal gland in sterile, pregnant and fertile but non-pregnant females and in reproductively active males.

Pinealocyte ultrastructure has been studied in four sterile, four pregnant and three fertile but non-pregnant females, and also in three reproductively active male pigmented Duncan Hartley guinea pigs. Synaptic ribbons are dense, rod-like structures with a linear arrangement of clear vesicles periodically spaced on both sides of the rodlet. Although these structures were observed in the pinealocytes of all of the animals studied, they were scarce and difficult to locate in tissue from the fertile, non-pregnant females and from the reproductively active males. They were numerous in the pineal glands of the pregnant and sterile females. Typically they lie perpendicular to the cell membrane of the pinealocyte polar process and in close proximity to a polar process of a neighboring cell. The increased incidence of synaptic ribbons in pinealocytes which appear to be in a heightened state of activity strongly suggests a function for this structure. Synaptic ribbons are also present in sensory systems such as rods and cones of the retina, hair cells of the organ of Corti and hair cells of the vestibular apparatus. This fact, plus the photoreceptor function of pinealocytes in lower vertebrates, lends credence to the possibility that this structure may serve a sensory or receptor function in the guinea pig gland.


Effects of L-proline and some of its analogs on retinal spreading of depression.

L-Proline inhibits glutamate-based spreading depressions (SDs) at low concentrations (2--2.5 mM) and promotes K+-based SDs at higher concentrations (5 mM). The inhibition of glutamate-based SDs was postulated to be due to competition of L-glutamate and L-proline for glutamate receptors on somatic and dendritic plasma membranes. The binding of proline to glutamate receptors was furthermore postulated to result in a release of K+ from the intracellular compartment, enhancing the extracellular K+ concentration sufficiently to promote K+-based SDs. A proline analog, L-baikiain, containing a double bond and one more C atom in the ring structure than proline had similar effects as the latter amino acid, but an analog, L-azetidine-2-carboxylic acid, with one less C atom in the ring had little effect on SD in the retina.


Primitive nervous systems: electrical activity in ventral nerve cords of the flatworm, Notoplana acticola.

Electrical activity evoked in the major cords of the ventral submuscular nerve plexus were measured. Recording and stimulation utilized suction electrodes attached directly to exposed nerve cords. Four categories of potentials have been recorded: (a) short latency spikes which have relatively high thresholds and appear to be single units; (b) short duration fast compound spikes that are made up of a small number of large units; (c) long duration compound potentials that are made up from a large number of smaller units, and (d) small amplitude potentials with long latencies and a characteristic shape. These can be conducted diffusely through the nerve plexus. The first two categories of spikes are called "fast" potentials because of their characteristic rise and fall times and the last categories are known as "diffuse" potentials. The spikelike fast potentials were only recorded from the main trunks (nerves VI), while diffuse potentials could also be recorded from side branches of these nerves. The diffuse potential appears to be conducted throughout the plexus but preferential conducting pathways occur around lesions. Both diffuse and fast potentials show facilitation of response to repeated stimulation. Facilitation can be demonstrated in the presence of high Mg2+ concentrations. Conductance of the diffuse potential also occurs in the presence of high ambient Mg2+. In Ca2+-free medium containing 1-mM EGTA one can also observe facilitatory events. The possibility of Mg2+-insensitive synapses is discussed.


Primitive nervous systems: electrophysiology of inhibitory events in flatworm nerve cords.

Evoked potentials from the major longitudinal nerve cords of Notoplana acticola are potentiated if the preparation is decerebrated or if certain nerves in the ventral submuscular plexus are severed. Concomitant with an increase in amplitude of the response (in some preparations over fourfold) is a decrease in latency of the response and a decrease in the threshold stimulus intensity needed to evoke activity. Evoked activity can also be depressed with moderate increases in stimulus intensity and is induced some distance from the recording site. The depressant effects can be lifted if the brain is bisected, if the contralateral nerve VI is severed close to the brain, and if the commissures between the two nerves VI are cut. The depressant effects of nerves V and VI are additive. Depression and the subsequent lifting of the inhibition occur in Ringer baths containing either normal sea water or equal mixtures of sea water and isotonic MgCl2. The possibility of inhibitory synapses immune to high concentrations of magnesium ions is discussed.


Functional characterization of the neurodepressing hormone in the crayfish.

The effect of the neurodepressing hormone (NDH) was studied on different identified motoneurons in the abdominal ganglia of the crayfish Procambarus bouvieri (Ortmann). Although differences in sensitivity were apparent, all the neurons tested responded to NDH with a reduction in spontaneous firing rate, which lasted as long as NDH was present, and, depending on the concentration and time of action of the hormone, for even longer periods. NDH activity was determined in the various parts of the central nervous system of the crayfish, being highest in the eyestalk, gradually diminishing away from the eyestalk, with a cephalo-caudal gradient, being lowest in the abdominal ganglia. High levels of NDH activity were detected in the blood. After eyestalk ablation, NDH concentration steadily diminishes in the blood and central nervous system, until virtually disappearing after 4 days; from day 5 onwards, the activity is recovered up to its original levels. NDH synthesis takes place with a time constant of approximately 3 hr in cultured isolated segments of central nervous system, being highest in the eyestalk.


Bis(L-cysteinato)gold(I): chemical characterization and identification in renal cortical cytoplasm.

L-Cysteinatogold(I) was prepared by the reaction of L-cysteine with KAuBr4 in acidic media and its solubility determined from pH 4 to 10. The solubility at pH 7.4 and 37 degrees C is 1 microM. In the presence of excess cysteine, the solubility increases because of formation of bis(L-cysteinato)gold(I). The equilibrium-constant for formation of the bis complex is 2.1 +/- 0.4 X 10(-3), which at pH 7.4 CORRESPONDs to an apparant formation constant of 4.4 X10(4). The formation of the bis adduct was confirmed by chromatographic separation of the products of the reaction between [35S]-L-cysteine and Na2AuTM. This complex elutes with Kav = 1.15 which allows it to be distinguished from other gold thiolates that might form in vivo. The bis(cysteinato)gold(I) complex is shown to be present in kidney cytosol isolated from rats given Na2AuTM in vivo. When additional cysteine is added to the cytosol in vitro, the peak at 1.15 is increased, but if glutathione is added, the low molecular weight gold elutes at Kav = 1.00, which is taken as evidence for the existence of bis(cysteinato)gold(I) in the cytosol preparation. The amount of gold present as bis(cysteinato)gold(I) after 4 different dose schedules has been measured and found to increase with the total cytosol gold concentration. L-Cysteinatogold(I) does not dissolve in the presence of bovine serum albumin to form an adduct.


Difficulties in diagnosis of supratentorial gliomas by CAT scan.

The false positive and false negative computed tomography diagnoses of glioma made using an EMI 1010 machine on a consecutive series of patients seen over a period of two years are recorded. About 1.5% of gliomas were not detected on initial CAT scan, 6.5% were misdiagnosed as benign lesions, and in 6.5% of the cases identified as glioma a non-malignant condition was subsequently diagnosed.


Ultraviolet-mediated cytotoxic activity of phenylheptatriyne from Bidens pilosa L.

The tropical weed Bidens pilosa L. (Asteraceae) contains a number of polyacetylenes which are phototoxic to bacteria, fungi, and human fibroblast cells in the presence of sunlight, artificial sources of long-wave ultraviolet light, or cool-white fluorescent light. The principle photoactive compound in the leaf, phenylheptatriyne, is present in the cuticle as well as in the underlying cells. Experiments with calf thymus DNA indicate that, unlike photoactive furanocoumarins, phenylheptatriyne does not form interstrand cross linkages with DNA in ultraviolet light.


Papilloedema, CSF pressure, and CSF flow in cerebral tumours.

The presence or absence of papilloedema and the cisternal CSF pressure were compared with the RIHSA cisternograms in 24 patients with supratenotorial tumours. It was found that severe subarachnoid obstruction of CSF flow, leading to impaired CSF absorption at the superior sagittal sinus, was the main cause of raised CSF pressure and papilloedema associated with supratentorial tumours.


Characterization of an irritant 4-deoxyphorbol diester from Euphorbia tirucalli.

Latex of Euphorbia tirucalli, collected in Colombia, yielded 12-O-2Z-4E-octadienoyl-4-deoxyphorbol-13-acetate (1), which exhibited an irritant potency equivalent to that of the standard irritant, phorbol-12-tetradecanoate-13-acetate, in a mouse ear test system. The unsaturated 4-deoxyphorbol diesters recently reported in E. tirucalli grown in South Africa were not observed in the present study.


Dementia paralytica: deterioration from communicating hydrocephalus.

Five patients suffering from dementia paralytica who failed to improve or deteriorated after one or several high dosage courses of penicillin, had pneumoencephalographic patterns suggesting communicating hydrocephalus. Measurements of the ventricular index, ratio of cella media to width of the temporal horn, and the callosal angle differed from that in seven cases of dementia paralytica with associated cerebral atrophy. An isotope cisternogram in three cases with communicating hydrocephalus further confirmed a blockage of the cerebrospinal fluid (CSF) at the parasagittal subarachnoid space. Three patients exhibited the full syndrome of gait apraxia, incontinence, and pyramidal tract signs associated with a severe degree of dementia. Shunting of the CSF in three cases was followed by immediate improvement in two, one in a longlasting way. No active parenchymal inflammation was observed in any of three brain biopsy samples taken during surgery, except for leptomeningeal fibrosis in one. Chronic leptomeningitis in dementia paralytica may impair subarachnoid CSF absorption with subsequent communicating hydrocephalus. Progression or inadequate responses after therapeutic dose of penicillin in dementia paralytica should prompt investigation for this complication as an alternative, effective treatment could be offered.


Biological and phytochemical investigation of plants XV. Pteryxia terebinthina var. terebinthina (Umbelliferae).

Aqueous extracts of Pteryxia terebinthina var. terebinthina were shown to possess antiarrhythmic activity. A novel furanocoumarin, pterybinthinone, the known coumarins pteryxin and umbelliferone, and sucrose were isolated from this plant. Attempts to re-isolate a structurally undefined, defibrillatory substance by means of a published protocol were unsuccessful.


Early and preventable changes of peripheral nerve structure and function in insulin-deficient diabetic rats.

Structure and function of peripheral nerve in early insulin deficient streptozotocin diabetic rat were examined. Quantitative studies of myelinated fibres from electron micrographs showed that the fibre calibre and slope coefficients of regression lines between axon and myelin areas were reduced and quantitation of unmyelinated fibres revealed a 40% reduction in area fraction of smooth endoplasmic reticulum. The difference in conduction velocity between diabetic rats and control rats increased with time just as does the difference in fibre calibre. Insulin treatment was able to prevent the decrease in conduction velocity as well as the reduction in fibre calibre. It is concluded that the early structural axon abnormalities results from the diabetic state and cannot be explained by poor general condition of the animals.


Antineoplastic activity and cytotoxicity of flavones, isoflavones, and flavanones.

Several hundred flavonoid derivatives, natural and synthetic, which have been tested in the screening program of the National Cancer Institute, have been examined for indications of structure-activity relationships which might exist among these compounds. No such relationships are apparent. In spite of occasional activity these compounds do not warrant further detailed pursuit as anti-tumor agents.


Malignant mesenchymoma of ulnar nerve: combined sarcoma of nerve sheath and rhabdomyosarcoma.

Malignant mesenchymoma within the right ulnar nerve of an 8 year old boy is described. The patient did not have stigmata of von Recklinghausen's neurofibromatosis. The growing and painful tumour was excised five and a half detection, and recurred five months later. Mingling of the nerve sheath sarcoma and rhabdomyosarcoma was noted within the same mass which was separated from the adjacent striated muscles. It is suggested that this mesenchymoma arose from mesenchymal cells or cells of mesenchymal type comprising the peripheral nerve sheath which is derived from ectomesenchyme of the neural crest.


Xanthochromic cysts associated with meningioma.

Three cases of cystic meningioma encountered in one year are presented. It appears from a review of the literature, and an analysis of these three cases, that large xanthochromic cerebral cysts may be associated with meningiomas in any of three configurations: (1) centrally within the tumour; (2) peripherally within the tumour; (3) in the adjacent brain. Regardless of which configuration applies, the CAT scan appearance of such cystic meningiomas may mimic that of a glial tumour with cystic or necrotic change, and lead to an incorrect presumptive diagnosis. This false impression may be perpetuated by the gross appearance at operation, which can also mimic malignant glioma. Although several radiological features should suggest the possible presence of a cystic meningioma, we know of no definite radiological means of differentiating this lesion from the more common malignant glioma. This finding should underline the need to biopsy all suspected cerebral neoplasms, regardless of how much their appearance on CAT scan may suggest malignant glioma.


3-Methylhistidine excretion as an index of myofibrillar protein catabolism in neuromuscular disease.

Myofibrillar protein catabolism has been calculated in a variety of neuromuscular diseases from the amount of 3-methylhistidine excreted in the urine. It was found to be significantly raised in Duchenne type muscular dystrophy, motor neurone disease, polymyositis, and thyrotoxic  myopathy. In Becker type muscular dystrophy the level was slightly raised. It was normal in scapuloperoneal and limb girdle dystrophy, dystrophia myotonica, extrapyramidal disease, and multiple sclerosis. It was significantly decreased in hypothyroid myopathy.


Centronuclear myopathy.

Centronuclear myopathy occurring sporadically in two African female children is reported, with details of clinical history and histological, histochemical, and ultrastructural findings, and a review of 58 previously reported cases. In spite of distinctive histological features, the clinical presentation of this condition is variable, there are different modes of inheritance, and the pathogenesis remains unclear.


Myokymia and impaired muscular relaxation with continuous motor unit activity.

We have studied two cases of the syndrome of myokymia and impaired muscular relaxation with continuous motor unit activity. Both patients complained of muscle twitching, weakness, stiffness, and hyperhydrosis during their illness. Myokymia was present over the entire body in both. On repetitive testing of muscle strength each patient showed initial fatigue followed by increasing strength as he continued his efforts. Both patinets improved on phenytoin therapy at high blood levels. Nerve conduction velocities were decreased. Electromyograms showed continuous electrical activity at rest which persisted during sleep and spinal anaesthesia but was diminished by curare. Intravital staining with methylene blue in one case demonstrated sprouting and beading of motor nerve terminals with multiple innervation of muscle fibres. The neurophysiological and pathological findings in these two cases indicate an abnormality of peripheral nerve in this disorder.


Assessment of directional Doppler ultrasound techniques in the diagnosis of carotid artery diseases.

Three diagnostic techniques based on the use of directional doppler ultrasound have been evaluated in comparison with direct percutaneous carotid angiography and arch aortography. The results indicate that the non-invasive techniques provide a safe, atraumatic method of assessing patients with symptoms of extracranial occlusive arterial disease.


Visual perseveration in temporal lobe epilepsy.

Ictal visual perseveration is reported in two patients with temporal lobe epilepsy. A distinction is drawn between visual perseveration and palinopsia, or recurrence of a visual image.


Transient global amnesia: an extensive case report.

A case of transient global amnesia was studied in detail. Of note was a temporally extensive, although quite patchy, retrograde amnesia during the event for information recallable at other times. While a consolidation block can explain the anterograde amnesia in transient global amnesia, the profound retrograde amnesia requires an additional block in the retrieval of old, established memories.


Lead-induced encephalopathy in dogs fed high fat, low calcium diets.

Growing, mongrel dogs were fed high fat (22%), low calcium (.1%) semipurified and purified diets with and without 77 ppm lead as lead acetate to experimentally induce the seizures and lead encephalopathy historically associated with accidental canine lead toxicity. Seizures were observed in 44% of the lead toxic dogs and microscopic encephalopathy was observed in 89% of the lead toxic dogs. The encephalopathy was characterized by bilaterally symmetrical areas of vacuole formation involving the neuropile especially in a laminar pattern at the tips of the gyri of the cerebral cortex. The spongy state was accompanied by capillary activation and gliosis. These lesions are similar to those reported in accidental lead toxicoses in other species but previous efforts to experimentally induce these lesions in young dogs fed low-calcium, normal-fat (16%) purified diets have been unsuccessful.


A quantitative study of the pigmented neurons in the nuclei locus coeruleus and subcoeruleus in man as related to aging.

The nuclei of the locus coeruleus and subcoeruleus were examined in human brains from individuals of 14 to 87 years. Serial counts were performed on every tenth Nissl stained paraffin section of melanin containing cells within the entire length of these nuclei. After 63 years, the neuronal population in these nuclei decreased 40%. This significant decrease in cell number is the first reported for a brain stem structure. In view of the relation of these noradrenaline containing cells to the catecholaminergic system and the widespread projections between these nuclei and other central nervous system structures, this decrease may be a factor in alteration of some central nervous system activities with increasing age.


Peripheral nerve demyelination induced by intraneural injection of experimental allergic encephalomyelitis serum.

Intraneural injection of sera from rabbits with experimental allergic encephalomyelitis, induced by sensitization with bovine brain white matter in complete Freund's adjuvant, produced focal primary demyelinative lesions in rat sciatic nerves. Demyelinating activity was removed by prior incubation of antisera with central (CNS) and peripheral nervous system (PNS) myelin but not with liver or kidney, and was heat-labile and complement-dependent. Recipient animals developed a sensorimotor disturbance of their toes and ankles on the side injected with antiserum. Twenty minutes after antiserum injection, Schwann cells showed focal cytoplasmic outpouching and their external mesaxons opened. Between 1 and 8 hours after injection vacuolation, splitting and vesiculation of myelin became increasingly prominent at Schmidt-Lanterman clefts and paranodal regions, with concomitant degenerative changes in Schwann cell cytoplasm. Polymorphonuclear cell infiltration and endoneurial edema were apparent at this time. Substantial demyelination occurred before the appearance of phagocytic cells. Between 8 hours and 3 days many nerve fibers were surrounded and attacked by invading macrophages. Axons became demyelinated progressively over several internodes by macrophage phagocytosis. Early signs of remyelination were observed by 5 days. These findings suggest that antibodies directed against antigens common to both CNS and PNS myelin can produce in vivo peripheral nerve demyelination.


Double replica technique applied to choroid plexus from early foetal sheep: completeness and complexity of tight junctions.

Choroid plexuses from early and late sheep foetuses were examined by an improved freeze-fracture technique and the use of double-replicas to define the structure of the tight junction network of the epithelial cells. 'Complex' strands which consist of two normal parallel strands separated by a single row of pits or particles are defined and demonstrated in complementary faces. Since this strand variety was encountered in the same proportion in the different development stages investigated, it could not be correlated with changes in permeability. It is more likely that the 'complex' strands are associated with the transfer of gap junction particles within the membrane. The question of the significance of discontinuities in P face ridges was also resolved by the double replica technique: the few discontinuities which were observed could be accounted for by particles in the complementary E faces. Furthermore, approximately the same number of such junction displacements was found in early and late stages which makes it unlikely that this phenomenon could contribute to changes in permeability. Thus it has not been possible so far to relate any structural feature of the tight junction network in developing choroid plexus epithelial cells with the reported changes in permeability of the blood-C.S.F. barrier.


Ultrastructure and quantitative synaptology of the sacral parasympathetic nucleus.

This study examines the anatomical substrate for the spinal micturition reflex. Light microscopy of pyridine silver-stained sections revealed that the sacral parasympathetic nucleus (SPN) exists as a broken column or chain of cell clusters located along the intermediolateral portion of the dorsal horn in sacral segments S2-S4. Quantitative analysis of neuropil components in electron micrographs provides data for each type of bouton identified in this nucleus. On the somata of these neurons, boutons containing clear spherical vesicles (S type) comprise 70% of the bouton population. Terminals containing three or more dense core vesicles (GS boutons) account for 26% and boutons containing flattened vesicles (F boutons) comprise 4% of the population. F boutons are more common on large dendrites where they comprise 10% of the total bouton population. The actual population density of each bouton type is most evident when the number of boutons is expressed as boutons per 100 micron of membrane length (btn/100 micron). S type boutons are the most frequently encountered type. The population density of S boutons is the same on soma and dendrites at 6.66 btn/100 micron. F boutons are more numerous on large (greater than 2 micron) dendrites (1.28 btn/100 micron) than on small dendrites (0.63 btn/100 micron) or on somata (0.36 btn/100 micron). GS boutons occur more frequently on small dendrites (3.66 btn/100 micron) than on somata (2.29 btn/100 micron), large dendrites (2.88 btn/100 micron) or medium dendrites (2.27 btn/100 micron). These data suggest that the dense core vesicle-containing boutons are applied primarily to small (less than 1 micron) dendrites and that F boutons are associated mostly with large or proximal dendrites. These results provide a quantitative profile of the synaptic input to the sacral autonomic (parasympathetic) neurons which innervate the urinary bladder and demonstrate specific population differences on various postsynaptic structures in this nucleus.


Ultrastructure of photoreceptors in the eye of Hermissenda labelled with intracellular injections of horseradish peroxidase.

The terminal processes of single and of pairs of identified photoreceptors in the eyes of the nudibranch mollusc Hermissenda crassicornis were studied by light and transmission electron microscopy after their somata were labelled by intracellular iontophoresis of horseradish peroxidase (HRP). The HRP spread from the somata into the axons and fine terminal processes within the neuropil of the cerebropleural ganglia. The photoreceptors ended in extensive secondary branches in the neuropil where previous electrophysiological studies had indicated the probable site of synaptic interactions between photoreceptors. Clear round vesicles (54-126 nm diameter) within labelled processes were similar to the vesicles found in the somata and axon hillocks. The terminal processes of pairs of type B photoreceptors contained different intensities of the HRP label. Uniform intensities of the HRP label were found in the terminal processes of single type B photoreceptors. These differences in intensity suggested that the terminal processes were from different type B photoreceptors. This finding suggests that the connections between type B photoreceptors are probably monosynaptic.


Neurogenesis and neuron regeneration in the olfactory system of mammals. II. Degeneration and reconstitution of the olfactory sensory neurons after axotomy.

This report describes the retrograde degeneration affecting olfactory sensory neurons of rats after severance of their axons and illustrates the reconstitution of new neurons originating from stem cells located at the base of the olfactory neuroepithelium. Degeneration of the mature, axotomized neurons, signalled by an increased electron density of their cytoplasmic matrix and by the appearance of lipofuscin-like granules, can be detected in the neuroepithelium as early as 24 h after surgery and becomes conspicuous between the second and the third day. Degenerating neurons can be observed in decreasing number up to the tenth post-operative day. They are removed by macrophages which invade the epithelium. The reconstitution of new neurons begins to occur after eight days, when the stem cells undergo vigorous mitotic activity and differentiate into neurons. The morphology of the reconstituted neurons has been described in detail at different stages of their maturation. After 30 days, the olfactory epithelium appears similar to controls. On the basis of both morphological (in rats) and autoradiographic ( in mice) observations, the basal cells have been recognized as stem cells of the olfactory neurons.


Ultrastructure of neurons in the auditory cortex of ageing rats: a morphometric study.

The cell bodies of pyramidal cells in layers II and V of rat auditory cortex were quantitatively examined in groups of rats 3, 6, 15, 23, 27 and 34-36 months of age. The mean diameters of cell bodies of both layer II and layer V neurons, as measured in 1 micron plastic sections, increased between 3 and 15 months of age, then decreased to a diameter that was less in the 36-month-old than in the 3-month-old rats. Morphometry of the nuclei of the cells was done by measuring nuclear area and nuclear envelope length directly on electron micrographs. In the layer II cells, neither parameter changed with advancing age. In the layer V cells, the mean nuclear area decreased significantly in the old animals and the mean envelope length increased. Point-counting techniques were applied to electron micrographs of cell bodies to determine the relative volume of selected organelles, inclusions and ground substance in the perikaryal cytoplasm. In this part of the study the chronological pattern of change in layer II and layer V pyramidal cells was similar. The relative volume of dense bodies increased linearly with advancing age, with a slightly more accelerated rate in layer II cells. The relative volume of ground substance remained essentially constant through 27 months, and then at 34-36 months decreased to 83% and 89% of the three-month level in layer V and layer II, respectively. The relative volume of the rough endoplasmic reticulum (RER) did not change significantly until after 15 months, at which time it began to occupy increasingly a larger fraction of the perikaryal cytoplasm. Finally, the relative volumes of mitochondria, multivesicular bodies and Golgi apparatus did not show clear trends of change during the 33-month period.


The formation of gap and tight junctions between retinal pigment cells in cell cultures.

The reformation of the junctional complex of retinal pigment cells was studied after trypsin disaggregation and in vitro reaggregation. Control specimens show a zonula occludens (tight junction) with integrated gap junctions and very large macular gap junctions. Isolation after trypsination results in disaggregation of the large gap junctions and fragmentation of the tight junctions with disaggregation of their integrated gap junctions. After two to four days of incubation the restoration of the zonula occludens is complete. After approximately five days of incubation, large gap junctions are found with a patchy arrangement of particles similar to that seen in vivo.


Development of synaptic ultrastructure at neuromuscular contacts in an amphibian cell culture system.

Cultures of dissociated myotomal muscle and spinal cord derived from embryos of Xenopus laevis were grown in the presence of curare in order to abolish neuromuscular activity and were examined by electron microscopy. In one-day-old cultures a few of the neuromuscular contacts already displayed several synaptic specializations including 500 A vesicles clustered against the axolemma, increased axolemmal densities, basal lamina in the cleft, an increased sarcolemmal density and subsarcolemmal filamentous material. Contacts with these specializations were observed more frequently in two and three-day-old cultures. Throughout the three-day culture period nerve fibres and neuromuscular contacts were devoid of Schwann cells. Isolated patches of basal lamina were relatively scarce and were usually accompanied by an increase in sarcolemmal density and subsarcolemmal filamentous material even in cultures in which spinal cord cells were not included. These observations indicate that the myotomal neuromuscular synapse differentiates in culture in much the same way as it does in vivo, that muscle contractions are not required for its differentiation, and that apparent postsynaptic specializations can develop in the absence of innervation.


Relation of cerebral blood flow to neurological status and outcome in head-injured patients.

Noninvasive studies of regional cerebral blood flow (CBF) were performed on 36 head-injured patients in varying degrees of coma, using the intravenous xenon-133 method. Serial examinations, averaging four per patient, were begun during the acute phase of illness and continued until death of recovery of normal consciousness. Comparison of the initial and final studies revealed that CBF declined to very low levels in all nine patients who died, and remained subnormal in a patient with persistent vegetative state. In contrast, 25 of 26 patients who recovered consciousness showed increases in blood flow. Because of the presence of both reduced and elevated blood flows on the initial study, CBF was not predictive of outcome. Absolute or relative hyperemia, observed in nine acute cases, was associated with either diffuse cerebral swelling (observed on computerized tomography) or recovery from systemic shock. Cerebral metabolic studies in hyperemic patients yielded a very low oxygen uptake and arteriovenous oxygen difference, indicating that the high blood flow was a true "luxury perfusion." When instances of presumed luxury perfusion were excluded, CBF was positively correlated with level of consciousness, assessed on a four-point coma scale.


Failure of high-dose steroid therapy to influence intracranial pressure in patients with severe head injury.

While corticosteroids in standard neurosurgical dosage do not appear to influence recovery from severe head injury or elevated intracranial pressure (ICP), some reports claim that a much higher dose is effective. A resultant hypothesis is that an abrupt increase in corticosteroid dosage in patients with severe head injury should cause a detectable reduction in ICP and in cerebral elastance within 48 hours. To test this hypothesis 20 consecutive patients with severe head injury, 12 of whom had had surgical decompression of mass lesions, were studied. All patients were artificially ventilated, and had continuous monitoring of ICP and intermittent testing of elastance by measurement of the volume-pressure response (VPR). For the first 12 hours after admission, patients received methylprednisolone, 40 mg every 6 hours. The dose was then increased abruptly by giving a single dose of 2 gm and 500 mg every 6 hours for the next 24 hours, then tapering rapidly. No significant change in ICP or VPR could be detected after 24 or 48 hours of high-dose steroid therapy. Of the 20 patients, 50% had good recovery or were moderately disabled, 15% were severely disabled or vegetative, and 35% had died. The course of ICP and the outcomes in these patients were not significantly different from those observed in a previous group of 262 patients managed in the same way for the high-dose regimen. There was, however, high incidence of gastric hemorrhage (50%) and of hyperglycemia with glucosuria (85%) in these 20 patients. These negative results in patients with head injury stand in marked contrast to our experience of the benefit of methylprednisolone in patients with brain tumors.


Cerebrospinal fluid cytology after subarachnoid hemorrhage.

A method is described which has been found capable of detecting subarachnoid hemorrhage (SAH) up to 15 to 17 weeks after its occurrence. The episode of SAH was confirmed by bloody and/or xanthochromic cerebrospinal fluid (CSF) at the time of SAH onset. In this study, 47 samples of lumbar CSF from diagnostically confirmed SAH patients were used. The CSF cells were collected onto slides and stained with May-Gruenwald-Giemsa or Perl's reagent. Iron-positive cells were detected at 1 week, increased by 4 to 6 weeks to 8.5% of total nucleated cells, and decreased to 1% by 15 to 17 weeks. All 27 samples obtained at 2 to 9 weeks after SAH showed iron-positive cells. No iron-positive cells (false-negative samples) were noted in 25% (one of four) of samples obtained during the first week, and in 33% (one of three) of samples obtained 10 to 12 weeks and 15 to 17 weeks after SAH. Of the total samples (37) obtained within 17 weeks after SAH, 8.1% (three of 37) were false negative. No iron-positive cells were detected in samples obtained later than 21 weeks after the SAH episode (10 samples).


New data on diastematomyelia.

Five cases of diastematomyelia are described and illustrated. These and a further 60 cases from the literature are analyzed. The data corroborate the opinion that early diagnosis and treatment result in a better prognosis.


Cervical myelopathy caused by developmental stenosis of the spinal canal.

The authors present six patients with myelopathy caused by developmental stenosis of the cervical spine. Hyperextension injuries precipitated the onset of symptoms in two patients, aged 19 and 20 years. In four, 41 to 69 years of age, symptoms were gradual in onset, progressing to severe disability. X-ray films revealed narrowing of the dorsoventral diameter of the spinal canal to as little as 1.0 cm. The myelograms showed widening of the cord in the transverse plane strongly suggestive of an intramedullary tumor. A unique finding was maldevelopment with flattening of the neural arch often hidden by the posterior portions of the articular facets when seen in the lateral views. These patients showed no significant evidence of spondylosis, arthrosis, or any of the structural stigmata usually observed in cervical spondylotic myelopathy. When indicated, decompressive laminectomy is the treatment of choice.


Traumatic asphyxia: an unusual cause of traumatic coma and paraplegia. Case report.

An unusual case of traumatic asphyxia with cerebral and spinal cord symptoms is presented. A survey of the literature indicates that a primary cord lesion is very rare as a consequence of such a trauma. The possible pathogenetic mechanisms of these neurological manifestations are discussed.