Alterations in bone-marrow cellularity following thymectomy in rats

Summary The number of nucleated marrow cells was decreased following neonatal thymectomy in rats, and was corrected by administration of syngeneic lymphoid cells, or by implantation of a syngeneic testis. These results suggest that, in the rat, as has been shown previously in the mouse, lymphoid cells exert parital control over bone marrow cellularity and this effect may be further modulated by sex steroids.Supported in part by NSF-RIAS 77-06922, NIH AM21137 and the Morseman Foundation.     

极性分子对甲基丙烯酸丁酯/丙烯酰胺共聚合的影响

以自由基本体聚合方法制备了甲基丙烯酸丁酯/丙烯酰胺(BMA/AM)共聚物.将极性分子环己醇引入到BMA和AM的共聚体系中,研究了环己醇对单体转化率和BMA/AM共聚物特性黏度的影响.随着环己醇加入量的增加,AM在反应体系中溶解的量明显增大,单体转化率增加,BMA/AM共聚物的特性黏度存在峰值.借助傅里叶变换红外(FTIR)、核磁共振(13C NMR)、动态力学分析法(DMA)、差示扫描量热法(DSC)和热重分析法(TGA)研究了环己醇对BMA/AM共聚物的结构和性能的影响,结果表明:AM只能与BMA进行共聚反应,随着环己醇的加入量的增加,BMA/AM共聚物的含量将增加,由此发泡阶段的酰亚胺化反应程度就越高,BMA/AM共聚物分子链中的酰亚胺环结构就越多,从而显著提高BMA/AM共聚物的性能,有望制备高性能的聚甲基丙烯酰亚胺(PMI)泡沫塑料.     

A simple method for the preparation of antibodies to the mitochondrial biotin-dependent carboxylases

Summary Heterologous antiserum to the 3 biotin-dependent carboxylases was prepared by selective removal of these enzymes from human liver on an avidin-sepharose column. A carboxylase-avidin-sepharose matrix was used as an antigen to produce anti-carboxylase antibodies. The resultant antisera can be used to purifiy the specific carboxylases, to prepare monoclonal antibodies to these enzymes or to study inherited carboxylase deficiencies and biotin-dependent intermediary metabolism.The authors thank Dr Emmanuel Shapira for his helpful suggestions and Patricia Tuck for her technical assistance. This work was supported by NIH research grants AM25675 and AM26127. Barry Wolf is a recipient of an NIH Research Career Development Award (AM00677) and is aided by a Basil O'Connor Starter Research Grant from the National Foundation—March of Dimes (5–263). This is paper No. 137 from the Department of Human Genetics — Medical College of Virginia.     

Immunochemical detection of arbuscular mycorrhizae

The difficult systematics of the arbuscular mycorrhiza (AM) forming-fungi, belonging to the Glomales, can be facilitated with immunochemical methods. Polyclonal antibodies, however, are seldom able to reach below the generic level. Monoclonal antibodies (mAb) have been produced which can differentiate AM fungal spores on the species and strain/isolate level. Together with an improved enrichment procedure for spores and hyphae of AM fungi, isolation and identification of the extraradical structures is possible with these mAb, lowering the risk of unspecific binding. Quantification of the data is discussed as the next step.This paper is dedicated to Prof. Dr. Peter Sitte on the occasion of his 65th birthday.     

Physiological mechanism by which acetyl CoA carboxylase is regulated

Summary Compared with rats fed a normal diet, the activity of the protein inhibitor of acetyl CoA carboxylase in rat liver doubled after 48 h of fasting. Conversely, acetyl CoA carboxylase activity was diminished by nearly one half. In animals fasted and then subsequently refed a fat free diet, acetyl CoA carboxylase activity was elevated by nearly 9-fold, with a concomitant decrease in the activity of the protein inhibitor by about 9-fold as compared to fasted rats. Hence it appears that the regulatory protein inhibitor for acetyl CoA carboxylase is of physiological significance for fatty acid biosynthesis.This work supported by grants AM 01383 and AM 21148 from the National Institute of Artheritis, Metabolic and Digestive Disease. We thank Dr J. Porter for his support.     

Changes in beta-2 adrenergic receptor sensitivity with maturation of erythroid progenitor cells

Summary Erythroid burst forming units (BFU-E) were much more sensitive to the beta-2 selective adrenergic drug, salbutamol, than erythroid colony forming units (CFU-E) in an in vitro study of erythroid progenitor cells.This work was supported by USPHS Grant AM13211. B. Beckman is a USPHS Postdoctoral Fellow AM05960.     

Functional potential of ectopic marrow autotransplants

Summary Ectopic autotransplants of the marrow tissue, form within 4 weeks, stable nodules which respond to erythropoietic modulation in a manner similar to other parts of the marrow. The findings indicate that these autotransplants are an integral part of the total hemopoietic mass.This work was supported by NIH grants AM25510 and AM70551 DOE contract DE-AS03-79EV00899.     

Recycling of magnesium drive train components

With the development of new heat resistant magnesium alloys,the automotive industry has introduced several parts to the drive train.The rising number of large magnesium components will result in a higher quantity of automotive post consumer scrap.It was the aim of this work to find a reasonable alloy system for the recycling of these magnesium drive train components.A matrix of potential recycling alloys based on the magnesium alloy AM50 was prepared via permanent mould casting.The materials were investigat...     

Vitamin A antibodies: Application to radioimmunoassay

Summary A radioimmunoassay for serum vitamin A is described which can detect as little as 1 ng of retinol. The statistical characteristics of this assay are presented and its use in a nutritional experiment is discussed.This work was supported by United States Public Health Service grant 2 RO1 AM19716.     

Antagonism of catecholamine inhibition of insulin secretion by methysergide

Zusammenfassung Isoliertes Maus-, Hamster- und Kaninchenpankreas wurde in einer physiologischen Pufferlösung mit 3,0 mg/ml Glukose inkubiert. Dopamin ruft eine erhebliche Verringerung der radioimmunologisch reagierenden Insulinsekretion hervor. Die durch Dopamin ausgelöste Hemmung lässt sich teilweise oder vollständig durch den Serotoninantagonisten 1-Methyl-d-lysergsäure butanolamid (Deseril) aufheben.

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Supported by grants from the National Institute of Arthritis and Metabolic Diseases of the National Institutes of Health No. AM 01324, No. 5 T1 AM 5074 and No. K3 AM 17,954 and a Clinical Investigatorship from the Veterans Administration (JMF).     

Mucosal growth effect of Vitamin D on the duodenum

Zusammenfassung Nach mehrmonatiger Vitamin-D-freier Diät erhielt eine Testgruppe von Ratten Vitamin D. Diese zeigte in Vergleich zur Kontrollgruppe eine Zunahme des Schleimhautgewichtes im Duodenum, nicht aber im Ileum.

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This work was supported in part by Training Grant No. T₁AM 5390 and Research Grant No. AM 02354 from the National Institutes of Health.     

Structural alterations in rat kidney proximal tubules perfused with fresh autologous serum

Summary Two min of intraluminal perfusion of the rat proximal tubules with autologous serum induced marked ultrastructural alterations including extensive cytoplasmic vesiculation due to swelling of rough endoplasmic reticulum cisternae and occasional extrusion of nuclei and cytoplasm into the lumen. Within 4 min pronounced vesiculation of mitochondria was observed. These findings are consistent with the notion that serum-induced inhibition of proximal tubular fluid absorption is due to cell lysis, presumably mediated by complement activation.Acknowledgment. This study was supported by NIH grants AM16258, AM27857, a New York Health Council grant, and a Veterans Administration Research grant.     

Suppression of PHA-induced lymphocyte blastogenesis by concomitant presence of PPD in the culture

Summary PHA-induced lymphocyte blastogenic response was remarkably suppressed by the simultaneous presence of PPD in cultures of lymphocytes derived from individuals sensitized to PPD, but not affected by the presence of PPD when the cultures contained lymphocytes from an individual not sensitized to the protein. This double stimulation blastogenesis study with PHA and a specific antigen is feasible as a simple and rapid test to measure cell-mediated immunity to the antigen.Supported by United States grant USPHS Grant AM 27384.     

Biochemical approaches to the study of plant-fungal interactions in arbuscular mycorrhiza

This communication compares some biochemical methods for quantifying colonization by arbuscular mycorrhizal (AM) fungi. The degree of mycorrhizal colonization can conveniently be measured by determining fungal specific sterols. AM-colonized plants show a specific synthesis of 24-methylene cholesterol and an enhanced level of campesterol (=24-methyl cholesterol). A gene probe for nitrate reductase, the key enzyme for nitrogen assimilation, has been developed, which allows the monitoring of the distribution of this enzyme in fungi. Among the phytohormones tested, only abscisic acid (ABA) is found at a considerably higher level in AM-colonized plants than in controls. The concentration of ABA is about twenty times higher in spores and hyphae of the AM fungusGlomus than in maize roots. Other phytohormones (auxins, cytokinins) do not show such alterations after mycorrhizal colonization. The roots of gramineous plants become yellow as a result of mycorrhizal colonization. The yellow pigment(s) formed is (are) deposited in larger quantities in the vacuole(s) of the root parenchyma and endodermis cells during the development of the gramineous plants. A substance isolated from such roots has now been identified as a C-14 carotenoid with two carboxylic groups, and named mycorradicin.     

AM信号确认算法研究与仿真

通过分析短波段AM广播信号调制特性，定义了调制信号上下边带频谱相关系数和调制信号与包络检波信号频谱相关系数，并以语音检测相关参数作为辅助。由此提出一种对AM广播信号进行“身份验证”的信号确认算法。基于短波标准信道的仿真实验表明，所定义的两个参数对噪声和信道滤波鲁棒，该算法可直接应用于实际工程环境，具有重要应用价值。     

Partial sequence of the tyrosine region of neocarzinostatin

Zusammenfassung Das antitumoraktive Protein-Antibiotikum Neocarzinostatin wurde mit Dithiothreit in flüssigem Ammoniak reduziert und mit Chloressigsäure alkyliert. Tryptische Spaltung des tetra-S-carboxymethylierten Proteins ergab 5 Fragmente. Die Sequenz von 25 Aminosäureresten im tyrosinhaltigen Fragment H₃ wurde durchEdman-Abbau im automatisierten Sequenator ermittelt.

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This work was supported in part by Public Health Service Research Grants No. C-6516 from the National Cancer Institute and No. FR-05526 from the Division of Research Facilities and Resource, National Institutes of Health, to the Children's Cancer Research Foundation and by grants No. AM 04501 and No. AM 11794 from the National Institute of Arthritis and Metabolic Diseases to the Endocrine Unit, Massachusetts General Hospital.     

Histochemical demonstration of differences in AMP deaminase activity in rat skeletal muscle-fibres

Summary The histochemical method for AMP deaminase confirms that rat slow-twitch fibres contain less AMP deaminase activity than fast-twitch fibres. However, the enzyme appears similarly localized in all fibre types.This study was supported by NIH grant AM 21617.     

Determination and statistical comparisons of Michaelis-Menten kinetic parameters

Summary A method is described for determining and statistically comparing Michaelis-Menten kinetic parameters.This work was supported in part by a U.S.P.H.S. Grant No. AM 15745 from the National Institute of Arthritis, Metabolism and Digestive Diseases and by the Maine State Agricultural Experiment Station.     

Uterine morphology and glycogen deposition of pregnant rats after clomiphene citrate treatment during preimplantation stages

Summary Clomiphene citrate did not induce glycogen deposition in the uterine luminal epithelium of pregnant rats as it did in ovariectomized rats. However, the drug did alter the epithelial morphology which may be a factor in its postcoital contraceptive action.Acknowledgment. The advice and guidance of Dr W.J. Bo are respectfully and gratefully acknowledged. This work was supported by USPHS grant AM 08029-6. The clomiphene citrate was supplied through the courtesy of the Wm. S. Merrell Co., Cincinnati, Ohio, USA.