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BALBc mice immunized with Type III pneumococcal polysaccharide (SIII) had higher numbers of IgM plaque-forming cells (PFC) in the spleen than similarly immunized C57BL/Ks mice. The F 1 hybrids of these two strains had intermediate numbers of SIII-specific PFC. Analysis of the responses of F 2 and backcross strains indicated that the observed responses were compatible with results expected for control of the immune response to SIII at a single autosomal locus.

The levels of Cd, Cu, Pb and Zn were determined in washed hair samples from four test cows exposed to multiple lead production sources of contamination and four control cows that were not exposed. Cadmium and lead were found in significantly higher concentrations in the hair collected from the test cows than in the hair of the control cows. The mean concentration of Cd in the summer sample from the test cows' hair was approximately 16 times higher than that of the control cows, and the Pb concentration in hair of the test cows was approximately 75 times higher than that of the control cows. The hair concentrations of Cd, Pb and Zn were significantly affected by season and Cu and Zn concentrations varied significantly among the cows on each farm. There was no relationship between hair and milk lead concentrations. Reduction in lead exposure was reflected more rapidly in blood than in hair concentrations. These results demonstrate the value of using bovine hair samples in surveillance of environmental contamination, as well as other ecologic, epidemiologic and mineral metabolism research.

Tubular reabsorption of phosphate after release of complete ureteral obstruction in the rat. The excretion of phosphate was studied in rats after release of complete unilateral ureteral obstruction of 24 hours' duration. Marked differences were observed in the rate of excretion of phosphate between the control and the postreleased kidney. After release of unilateral ureteral obstruction, the fractional excretion of phosphate by the control kidney was greater than in normal rats, while the fractional excretion of phosphate by the experimental kidney was markedly decreased. The increased excretion of phosphate by the control kidney was abolished by prior parathyroidectomy and was attributed to an increase in the concentration of circulating parathyroid hormone. The low urinary excretion of phosphate by the experimental kidney could not be attributed to refractoriness of the renal tubule to the action of parathyroid hormone or to changes in the intrinsic capacity of the tubule to reabsorb phosphate. A marked decrease in the filtered load of phosphate is the most likely factor responsible for the low phosphate excretion by the experimental kidney. Support for this concept was obtained from studies in rats in which the filtered load of phosphate was decreased unilaterally by partially constricting the aorta proximal to the left renal artery. In these rats the fractional excretion of phosphate was considerably less in the constricted than in the contralateral normal kidney both before and after the administration of exogenous parathyroid hormone. In addition, a marked dissociation was observed between the rate of excretion of salt and water and the rate of excretion of phosphate in rats studied after release of unilateral ureteral ligation. Fractional excretion of sodium and water was greater in the experimental than in the control kidney whereas fractional excretion of phosphate was greater in the control than in the experimental kidney. These findings are consistent with the hypothesis that in the postobstructed kidney there is increased phosphate reabsorption in the proximal tubule and decreased sodium and water reabsorption in the distal tubule. Reabsorption tubulaire des phosphates apres levee d'une occlusion complete de l'uretere chez le rat. L'excretion des phosphates a ete etudiee chez rats apres levee d'une occlusion unilaterale de l'uretere pendant 24 heures. Des differences importantes ont ete observees dans les debits d'excretion de phosphate entre le renin controle et le renin libere. Apres la levee de l'occlusion unilaterale l'excretion fractionnelle des phosphates par le rein controle est plus grande que chez l'animal normal, alors qu'elle est tres diminuee du cote experimental. L'augmentation de l'excretion des phosphates par le rein controle est abolie par une parathyroidectomie prealable et elle est attribuee a une augmentation de la concentration circulante d'hormone parathyroidienne. L'excretion de phosphates faible par le rein experimental ne peut pas etre mise au compte d'une insensibilite du tube renal a l'action de l'hormone parathyroidienne ou de modifications de la capacite intrinseque du tube a reabsorber les phosphates. Une diminution importante de la charge filtree de phosphates est plus probablement le facteur responsable de la diminution de l'excretion de phosphates par le rein experimental. Des arguments en faveur de cette hypothese ont ete obtenus par l'etude de rats dont la charge de phosphates filtres a ete diminuee unilateralement par une constriction partielle de l'aorte en amont de l'artere renale gauche. Chez ces rats l'excretion fractionnelle de phosphates est tres inferieure du cote subissant la constriction a ce qu'elle est par le rein normal controlateral, aussi bien avant qu'apres l'administration d'hormone parathyroidienne. De surcroit, une dissociation nette a ete observee entre le debit d'excretion de sel et d'eau et le debit d'excretion de phosphates chez les rats etudies apres l'ablation de la ligature ureterale. L'excretion fractionnelle de sodium et d'eau est plus grande par le rein experimental que par le rein temoin alors que l'excretion fractionnelle de phosphates est plus grande par le rein controle que par le rein experimental. Ces constatations sont compatibles avec l'hypothese d'une reabsorption proximale de phosphate accrue et d'une reabsorption distale d'eau et de sodium diminuee dans le rein qui a subi l'obstruction.

Changes in the plasma free fatty acids of a pancreatectomized subject and in free fatty acids and insulin in 10 normal subjects in response to the in vivo infusion of epinephrine alone, epinephrine plus phentolamine, and epinephrine plus propranolol indicate that both alpha and beta adrenergic receptors are present in human adipose tissue. Under the experimental conditions used, adipose tissue appeared to be more responsive to epinephrine than did the cardiovascular system.

SUMMARY The problem of comparing several ordered dose levels with a control when a larger sample size is taken on the control is considered. The distributions of Bartholomew's tests are determined for the limiting case where the control mean is known and an approximation is given for the problem. The existing tables for Bartholomew's tests are extended. It is considered that these tests are superior in all situations where the sample size for the control is greater than the sample sizes for the nonzero dose levels.

A pronounced nonuniformity in films of Ta deposited by electron‐beam evaporation is reported. This effect is explained by the fact that positive Ta ions are generated during evaporation and, due to reflected electrons, the substrate acquires a high negative potential which accelerates the Ta ions and causes sputtering.

Analytical and Monte Carlo results are used to investigate the robustness of the exact statistical test suggested by Nelson for testing the hypothesis of equality of two availabilities. A non-parametric test based on a generalized U-statistic is proposed which does not depend on the assumption that the times to failure and times to repair are exponentially distributed. Additional Monte Carlo results are used to point out the strengths and weaknesses of this test.

The robustness of T2 for samples of size 5, 10 and 20 from several bivariate distributions is investigated. Samples are presented from bivariate normal, uniform, exponential, gamma, lognormal and double exponential distributions. Related observations on the one sample t and paired t are also given. Highly skewed distributions resulted in too many extreme values of T2 Other distributions gave conservative results. The use of the t-test and non-simultaneous techniques gave large overall levels of significance.

Extract: Normative data for total body potassium on 462 children (232 boys and 230 girls) are presented. The regression of total body potassium on weight can be described as a straight line for males (grams K = 4.32 + 2.12 × weight) and two significantly different lines for females (grams K = −1.50 + 2.32 × weight for weight ≤ 30 kg, and grams K = 34.90 + 1.11 × weight for weight > 30 kg), with less potassium per kilogram for females weighing more than 30 kg. No sex-related difference is found between 12 and 30 kg. When the regression of total body potassium on height is examined, it is found that a logarithmic transformation of potassium values results in a similar pattern, with no sex-related differences between 100 and 135 cm and less potassium per centimeter in females over this height. For males, log K in grams = 1.761 + 0.0182 × cm of height; and for females, log Kin grams = 1.595 + 0.01942 × cm for height ≤ 135 cm, and log K in grams = 2.574 + 0.01215 × cm for height > 135 cm. The logarithmic transformation of K versus height is proposed as a standard because it reflects changes in slope associated with known physiologic and endocrinologic changes occurring with puberty and may be more sensitive than weight in predicting abnormal values in individual patients. Speculation: Since the regression of total body potassium on height appears to be a straight line common to both sexes 100–130 cm tall, with a diverging line indicating progressively less potassium per centimeter for females over 135 cm in height, these data were compared with available data for infants. The total body K values of infants between 50 and 80 cm in length appear to fall on a line with a steeper slope than values of children 100 to 135 cm tall. This observation suggests that, during the 1st year of life, increasing total body potassium per centimeter of length reflects maturation of body composition. Further extension of such observations to low birth weight infants might be expected to give information on their body composition.

Ontogenic changes in respiratory pathways of skins of detached apple fruits were measured during a 4 month period. Results showed that an increase in pentose pathway occurred with increasing senescence in this tissue. Variation in temperature at any given age did not result in an alteration of the C6/C1 ratio. CO2 evolution from the pentose pathway in senescent fruit was directly related to O2 uptake. Glucose uptake increased with increasing senescence indicating a change in cell permeability.

Adenosine 3',5'-monophosphate (3',5'-AMP) was assayed in calvaria isolated from fetal rats at term. A marked increase in 3',5'-AMP was detected in vitro within 1 min after adding purified parathyroid hormone to calvaria incubated in Krebs-Ringer-bicarbonate or Krebs-Ringer-Tris buffer. A maximal effect was detected after 5 min of incubation with added parathyroid hormone. The lowest concentration of parathyroid hormone causing a significant effect was 0.05 µg per ml or 5 x 10-9 m. The response was a direct function of the log concentration of parathyroid hormone from 0.1 to 1.0 µg per ml, became maximal at 10 µg per ml, did not require potassium, magnesium, or calcium in the incubation medium, and was not inhibited by a high (5 mm) concentration of calcium. Epinephrine and prostaglandins E1 and E2 also caused a significant increase in skeletal 3',5'-AMP. The effect of epinephrine was abolished by propranolol, but this β-adrenergic blocking agent did not affect the response to the prostaglandins or to parathyroid hormone; phentolamine did not affect the response to any of these substances. Calcitonin caused a slight increase in skeletal 3',5'-AMP, but the maximal effect was small and the response was not related to the concentration of polypeptide. Only the effect of parathyroid hormone was clearly relatable to direct hormonal activation of adenyl cyclase in the tissue. Neither thyrotropin, corticotropin, glucagon, insulin, luteinizing hormone, growth hormone, adenosine 5'-monophosphate, guanosine 3',5'-monophosphate, 25-hydroxycholecalciferol, nor sodium fluoride affected the concentration of 3',5'-AMP in this test system. These findings provide further evidence that the physiological actions of parathyroid hormone are mediated by 3',5'-AMP.

A thin film fabricating and test apparatus has a substrate holder cart positioned on a pair of tracks within a tubular vacuum system. Feed through drive units operate to move the cart to positions adjacent deposition units and test units within the vacuum system. A second drive unit positions the cart and moves masks and test contacts to a position adjacent substrate. A third drive unit positions deposition control shutters adjacent the substrate.

SUMMARY Two methods for testing hypotheses concerning the equality of two proportions are compared. The first method is the large sample test for proportions considered in most elementary texts. The other method is applicable under more general assumptions than the first and requires a pairing of the observations from the two populations. The two procedures are compared, using three different measures of asymptotic efficiency, under conditions where both are applicable. At least for the measures of efficiency considered, the matched pairs procedure is shown to do almost as well as the usual large sample test.

A large area focusing X-ray collector constructed for a sounding rocket is described. The instrument consists of nested reflecting plates that are curved slightly in one dimension to form a set of parabolas with a common focus. An array of plates such as the one in the sounding rocket focuses a parallel beam of X-rays to a line. The reflecting surfaces are commercial float glass with an evaporated metallic coating such as gold or nickel. With a gold coating, the effective area of the rocket collector is about 250 sq cm for 0.3 keV X rays and about 150 sq cm at 1.2 keV. Its angular resolution is a few arc minutes and field of view is about plus or minus .75 deg (full width at half maximum). The collector performed successfully during a sounding rocket flight.

Cyclic adenosine 3',5'-monophosphate (cAMP) and cyclic guanosine 3',5'-monophosphate (cGMP) were measured in mammalian tissues and fluids by radioimmunoassay in a variety of physiological and pharmacological conditions. Basal concentrations and responses to hormonal stimuli were in close agreement with results from previous studies using other assay techniques. Cyclic nucleotide phosphodiesterase treatment of urine and trichloroacetic acid extracts of various tissues completely destroyed the immunoreactive material in each assay except for a tissue blank in kidney, liver, and skeletal muscle of 24%, 40%, and 15%, respectively, in the cGMP assay. The nature of this cross-reacting substance has not been identified. Hormonal stimuli causing marked increases in cAMP in vivo or in vitro did not affect the level of cGMP, indicating that the concentration of each of these nucleotides is controlled independently. Adrenalectomy caused an increase in cGMP in skeletal muscle, but did not affect cAMP in this or other tissues. The concentration of cGMP in skeletal muscle from adrenalectomized rats reverted toward normal after treatment with dexamethasone. Adenylate cyclase and guanylate cyclase activities in subcellular fractions were estimated by immunoassay of the amount of cAMP and cGMP formed from ATP and GTP, respectively. The high specificity and sensitivity of the cAMP and cGMP immunoassays allowed detection of cyclic nucleotide in the supernatant of the reaction mixture without prior concentration or separation procedures. No difference in adenylate cyclase activity in liver plasma membranes was observed between this technique and that of measuring conversion of [α-32P]ATP to [32P]cAMP. Guanylate cyclase activity was detectable in soluble fractions from liver and renal cortex and was not affected by glucagon, dexamethasone, thyroxine, or sodium fluoride added in vitro.

The effect of parathyroid hormone on adenyl cyclase from fetal rat calvaria was tested. Adenyl cyclase was assayed in particulate fractions from this tissue by measuring conversion of ATP-α-32P to 3′,5′-AM32P. Parathyroid hormone caused rapid stimulation of enzyme activity; the degree of stimulation was related to the log of hormone concentration. Adenyl cyclase in calvaria was not sensitive to a variety of hormones known to stimulate this enzyme in other tissues. The enzyme was sensitive to parathyroid hormone in skeletal and renal cortical tissue but not in heart, brain, spleen, thyroid, adrenal, or fat cells. Parathyroid hormone and sodium fluoride also stimulated theenzyme in calcified bone from adult rats. Neither parathyroid hormone nor thyrocalcitonin affected the activity of cyclic nucleotide phosphodiesterase in skeletal tissue, nor did thyrocalci tonin affect adenyl cyclase. These observations provide the basis for the concept that a single type of interaction between hormone and enzyme bound to...

Adenyl cyclase from plasma membrane fractions of rat renal cortex or medulla was assayed by measuring conversion of adenosine triphosphate labeled at the alpha-phosphate with (32)P to cyclic 3',5'-adenosine monophosphate labeled with 32P. Parathyroid hormone activated the enzyme primarily in cortex; vasopressin acted primarily in medulla. These experiments support the conclusion that cyclic adenosine monophosphate mediates the action of parathyroid hormone on the kidney and show that parathyroid hormone and vasopressin stimulate adenyl cyclase at anatomically separable areas within the kidney.

If the parameters are estimated independently of the sample, the chi-square test statistic for a goodness of fit test has a limiting distribution that is stochastically larger than that of the test of fit for a completely specified distribution. Thus, if the critical values for the test of fit for a completely specified distribution are incorrectly used, the probability that we will reject the null hypothesis when it is true is greater than the desired level of significance.

The vacuum deposition of refractory metals is of interest in the fabrication of metal-gate field-effect transistors and charge-coupled devices. Due to this interest a detailed study of characteristics of e-beam-deposited metals has been conducted and previously unreported nonuniformities observed. The experimental procedures are described, and the implications of and theories for the observed nonuniformities discussed. A self-accelerated, magnetically focused e-beam gun was used to deposit all films at an acceleration voltage of 19 kV. A previous study of e-beam-deposited tantalum films reported a similar nonuniformity caused by reflected high-energy electrons charging the substrates to a high negative voltage during deposition: this voltage accelerates positive tantalum ions toward the substrate causing sputtering. In the present study many metals commonly used in electron devices were deposited; in all cases the negative charging was detected. However, the nonuniformities were detected only in the refra...

Three adult patients with hypocalcemia secondary to severe magnesium depletion were evaluated in order to determine the etiology of hypocalcemia in this syndrome. In each patient, the concentration of circulating parathyroid hormone was within the range of normal despite severe hypocalcemia and hypomagnesemia. In the 2 patients tested, circulating parathyroid hormone increased transiently above normal in response to treatment with magnesium. Urinary excretion of phosphate and cyclic AMP increased normally in response to an acute infusion of parathyroid extract and serum calcium increased 2 mg/100 ml and 1.4 mg/100 ml, respectively, in response to intramuscular injections of the hormone in the 2 patients who were tested. It was concluded that the normal but inappropriately low concentrations of parathyroid hormone were attributable to hypomagnesemia and could account for the perpetuation but not the onset of hypocalcemia in this syndrome. Peripheral resistance to parathyroid hormone is not operati...

The 2 Drop Clinitest, 5 Drop Clinitest, Tes-Tape, and Ketodiastix semiquantitative urinary glucose methods were evaluated using 300 urine samples from diabetic patients and comparing the results with those obtained by an AutoAnalyzer-glucose oxidase method. At high levels of glycosuria (above 1,500 mg.'100 ml.) the 2 Drop Clinitest method gave better quantitation than the other methods. In this range the Keto-diastix method often gave falsely low results. At intermediate levels of glycosuria (376 to 1,500 mg.'100 ml.) there appeared to be little or no difference among the methods. The 2 Drop Clinitest method was often insensitive to levels of urinary glucose below 376 mg.'100 ml. In this range the other three methods gave comparable results, with the exception that Tes-Tape was sometimes positive with normal levels (1 to 15 mg.'100 ml.) of glycosuria. Proteinuria and pregnancy had no effect on any of the methods. Acetest was a more sensitive and accurate indicator of urinary ketone levels than Keto-diastix.

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In order to further assess nutritional status of Negro and white children aged 4 and 5 whose hematological and serum protein values were within normal range, body composition studies were done. Total body potassium was measured by whole body counting of gamma emissions of naturally occurring radioactive potassium (40K) with a 2π liquid scintillation counter. Standard anthropometric measurements were also performed. Results show no statistically significant difference in total body potassium in the two groups, regardless of sex. There are fat differences.

The basal cell nevus syndrome is an autosomal dominant trait which includes among its features jaw cysts, basal cell carcinomas, ectopic calcification and skeletal anomalies. It had been previously reported that such persons have had "resistance" to parathyroid hormone. In the current study, six persons with this syndrome from two families had a normal response to parathyroid hormone as measured by changes in serum calcium and phosphate and urinary excretion of calcium, phosphate and cyclic 3',5'-adenosine monophosphate. These results do not support the previous reports of "resistance" to parathyroid hormone in this syndrome.

An introductory section includes a brief resume of previous observations on the fluorescence of crude drugs and drug products exposed to ultraviolet radiation. A key for identification of powdered vegetable drugs based on their fluorescence under ultraviolet radiation is presented. Possible application of the method and its shortcomings are discussed.

Adenyl cyclase activity of chick oviduct homogenates after various conditions of in vivo hormonal stimulation was assayed by measuring the conversion of alpha 32P-ATP to 32P-cyclic 3′,5′-AMP. Oviducts from chicks injected with diethylstilbestrol (DES) showed no immediate change in adenyl cyclase activity, nor was there an activation with chronic DES administration. However, if chicks were given a single dose of progesterone, a delayed activation of adenyl cyclase was noted at 3–6 hr, and reached 250% of control by 24 hr. Enzyme activity at maximal progesterone stimulation was 50% of “total” adenyl cyclase activity as estimated with NaF. These studies suggest that 3′,5′-cyclic AMP does not play a primary role in response of the oviduct to DES, but may play a secondary role in the induction of avidin synthesis by progesterone. (Endocrinology 86:1019, 1970)

In 1956, prompted by Mao Zedong himself, the Qingdao symposium was convened to bring together scientists with training in "Morgan-Mendel" genetics and scientists following the Michurin school. The effects of government policy to this time had excluded the mostly western-trained geneticists from sharing their training, their skilled imagination and expertise, i n building China's agriculture. Michurin genetics, sponsored by Stalin's support of Lysenko since the 1940s, was based on the hypotheses that environmental influences were primary, including the idea of inheritance of acquired Characteristics. A study of Soviet influence is pertinent to understanding the importance of the 1956 Qingdao symposium. Doubts were already being voiced in China concerning the validity and sincerity of Soviet dictates and the quality of the advice being given in several realms of Soviet influence. This essay focuses on this event, which introduced a time of free discourse between these two ways of defining how to improve agricultural production, the Morgan-Mendel and the Michurinist., Author also known as: Alice R. Chase Robeson

THE BLAST, explosion and subsequent fire at Texas City was a catastrophic event, which only those present can fully picture. An ordinary industrial area was suddenly transformed into a city of tremendous havoc and destruction. Numerous reports in the press and a few in the medical literature attested to the magnitude of the disaster. It has been estimated, reliably, that between 3,000 and 4,000 people were injured. The most accurate sources report that approximately 600 persons were killed or reported missing as a result of an incident that took place in the course of a very few minutes. About 800 persons received injuries which were of sufficient severity to require hospitalization in Galveston and the surrounding communities. Four hundred of these were admitted to the John Sealy and affiliated hospitals of the University of Texas Medical Branch within twelve hours. Of this group only a very small percentage were admitted

Tubules were isolated from kidneys of rats after incubation with collagenase and the effect of parathyroid hormone on adenyl cyclase in this tissue was studied. Adenyl cyclase in homogenates of tubules was assayed by measuring conversion of ATP-α-32P to cyclic 3′,5′-AM32P. Incorporating an ATP-regenerating system (phosphoenolpyruvate and pyruvate kinase) enhanced the sensitivity of the system. Virtually all of the enzyme activity in the renal cortex was found in the tubules. Parathyroid hormone caused rapid activation of the enzyme in tubules from the renal cortex; enzyme activity was directly proportional to the concentration of parathyroid hormone over the range of 0.05 to 5 μg/ml. The effect of parathyroid hormone was much greater with tubules isolated from the renal cortex than with those from the medulla. In contrast, arginine vasopressin activated the enzyme in the medulla but not the cortex. Epinephrine, glucagon and thyrocalcitonin caused an increase in enzyme activity but showed no dose-response ...

Urinary excretion of cyclic adenosine 3',5'-monophosphate (3',5'-AMP) was tested in normal subjects and patients with pseudohypoparathyroidism, idiopathic hypoparathyroidism, surgical hypoparathyroidism, and pseudopseudohypoparathyroidism under basal conditions and after a 15 min infusion of purified parathyroid hormone. Basal excretion of the nucleotide was less than normal in the patients with hypocalcemic disorders and greater than normal in pseudopseudohypoparathyroidism. Parathyroid hormone caused a marked increase in excretion of 3',5'-AMP in all subjects except those with pseudohypoparathyroidism; nine patients with this disorder did not respond to the hormone and four showed a markedly deficient response. Radioimmunoassay showed that parathyroid hormone circulated in increased amounts in plasma from patients with pseudohypoparathyroidism and became undetectable when serum calcium was increased above 12 mg/100 ml. Suppression of parathyroid hormone secretion by induction of hypercalcemia did not alter the deficient response to exogenous hormone. The results indicate that: (a) parathyroid hormone circulates in abnormally high concentrations in pseudohypoparathyroidism and secretion of the hormone responds normally to physiological control by calcium; (b) testing urinary excretion of 3',5'-AMP in response to infusion of purified parathyroid hormone appears to be an accurate and sensitive index for establishing the diagnosis of pseudohypoparathyroidism; and (c) the metabolic defect of the disorder can be accounted for by a lack of or defective form of parathyroid hormone-sensitive adenyl cyclase in bone and kidney.

Washed human platelets were incubated with 0.1-1.0 U/ml human thrombin and the effects on adenyl cyclase activity and on a platelet membrane protein (designated thrombin-sensitive protein) were studied. Adenyl cyclase activity was decreased 70-90% when intact platelets were incubated with thrombin. The T½ for loss of adenyl cyclase activity was less than 15 sec at 1 U/ml thrombin. There was no decrease of adenyl cyclase activity when sonicated platelets or isolated membranes were incubated with these concentrations of thrombin. Loss of adenyl cyclase activity was relatively specific since the activities of other platelet membrane enzymes were unaffected by thrombin. Prior incubation of platelets with dibutyryl cyclic adenosine monophosphate (AMP), prostaglandin E1, or theophylline protected adenyl cyclase from inhibition by thrombin. Incubation of intact but not disrupted platelets with thrombin resulted in the release of thrombin-sensitive protein from the platelet membrane. The rapid release of this protein (T½ < 15 sec) at low concentrations of thrombin suggested that removal of thrombin-sensitive protein from the platelet membrane is an integral part of the platelet release reaction. This hypothesis is supported by the parallel effects of thrombin on adenyl cyclase activity and thrombin-sensitive protein release in the presence of dibutyryl cyclic AMP, prostaglandin E1, and theophylline at varying concentrations of thrombin.

Recent studies have expanded remarkably our understanding of the chemistry, physiology, mechanism of action, and clinical importance of the polypeptides—parathyroid hormone and thyrocalcit...

Eberhart, Bruce (University of North Carolina, Greensboro), David F. Cross, and Lewis R. Chase . β-Glucosidase system of Neuspora crassa . I. β-Glucosidase and cellulose activities of mutant and wild-type strains. J. Bacteriol. 87: 761–770. 1964.—A mutant strain, gluc-1 , of Neurospora crassa was isolated and characterized by its low level of β-glucosidase activity. The mutant was selected by testing irradiated colonies for extracellular β-glucosidase activity. Strains containing the gluc-1 gene were also visibly detected by their reduced ability to destroy esculin in their growth media. The mutant strain grew at wild-type rates with cellobiose or carboxymethylcellulose as carbon sources. This auxotrophic similarity with wild type is explained by the presence of at least two β-glucosidases (and possibly two cellulases) in Neurospora that act complementarily. The thermolabile β-glucosidase was destroyed after 1 min of incubation at 60 C. This enzyme was present in mycelia but absent in conidial extracts. A second β-glucosidase that is comparatively stable at 60 C was present in both mycelia and conidia. A partial separation of these enzymes was achieved with ammonium fractionation of mycelial extracts of gluc-1 and wild-type strains. Thermolabile β-glucosidase and cellulase activity appear not to be affected by the gluc-1 mutation, whereas the thermostable glucosidase is greatly reduced in gluc-1 strains.

Hypocalcemia and resistance to exogenous parathyroid hormone have been reported in several clinical states associated with magnesium deficiency. On the basis of such observations, it has been suggested that magnesium depletion per se may result in impaired responsiveness of the adenyl cyclase-adenosine 3′,5′-monophosphate (3′,5′-AMP) system. To test this hypothesis, 4 wk old male parathyroidectomized rats were maintained on normal or magnesium-deficient diets for 4 wk and their responses to parathyroid hormone compared. Serum magnesium and calcium fell progressively in the magnesium-deficient group. Despite clinical and biochemical evidence of severe magnesium deficiency in these animals, renal production and excretion of 3′,5′-AMP in response to parathyroid hormone was normal both in vitro and in vivo. Additionally, administration of either dibutyryl 3′,5′-AMP or parathyroid extract to fasting magnesium-depleted rats produced a normal increase in serum calcium. Parathyroid hormone infusion studies demonstrated normal renal and skeletal responsiveness as measured by urinary excretion of calcium, magnesium, phosphate, and hydroxyproline. These data show that the effect of parathyroid hormone on 3′,5′-AMP formation and excretion, the responsiveness of skeletal tissue to 3′,5′-AMP, and the renal and skeletal system responses to parathyroid hormone are not altered by pure magnesium deficiency in the parathyroidectomized rat.

The importance of adenyl cyclase and adenosine 3',5'-monophosphate in the induction of tyrosine aminotransferase by adrenocorticosteroids has been tested in HTC cells derived from a rat hepatoma and grown in tissue culture. Adrenocorticosteroids cause a 10-to 15-fold increase in the rate of synthesis of tyrosine aminotransferase in these cells. Under various experimental conditions, with or without glucocorticoids, neither adenyl cyclase nor cyclic adenosine mono-phosphate could be detected in HTC cells. In addition, neither the cyclic nucleotide nor N(6), O(2')-dibutyryl cyclic adenosine monophosphate caused increased activity of the transaminase in HTC cells. We conclude that induction of tyrosine aminotransferase by glucocorticoids is not mediated by the adenyl cyclase-cyclic adenosine monophosphate system.