Chromosome change during growth inPuschkinia libanotica L. (Liliaceae)

Summary The variation in chromosome size in root-tip meristem ofPuschkinia libanotica L. was studied at different days of root growth with special attention to DNA, RNA, total protein and histone contents. The results show that the size and organisation of chromosomes even within the one tissue is subject to considerable change during growth and development.The author is thankful to Prof. H. Rees, FRS, Department of Agricultural Botany, University College of Wales, Aberystwyth, Wales, U.K., for his guidance and to University College of Wales, Aberystwyth, for granting him a SRC fellowship.     

Gliogenesis during embryonic development in the rat

With the aid of thymidine-H3 autoradiography gliogenesis in the rat brain was seen to start during embryonic stages, which might continue into the postnatal stages of development. Gliogenesis followed a caudo-rostral gradient closely following neurogenesis. Ependymogenesis was found to occur in parallel with gliogenesis.     

Abnormalities in the development and reproduction of Blattella germanica (L.) (Dictyoptera: Blattellidae) treated with insect growth regulators with juvenile hormone activity

Summary Laboratory populations of German cockroach reared on food treated with R-20458 (75 ppm) or Ro 20-3600 (3000 ppm) became completely sterile and eventually extinct. The hypertrophied oocytes had excessively laid chorion, and the hypertrophied accessory sex glands contained excessive amounts of protein.     

Binucleated neurons in the central nervous system of the laboratory animals

Summary Binucleated neurons were studied in the central nervous system of the rat and the rabbit. They were present in the young as well as the adult animals. The animals injected with thymidine-H³ during their embryonic development showed labelled binucleated neurons. It is suggested that the neurons become binucleated during neuroembryogenesis, and differentiate into normal neurons morphologically and physiologically.Supported by NIH Research grant No. NS-08817-05.     

A subset of NSAIDs lower amyloidogenic Abeta42 independently of cyclooxygenase activity.

Epidemiological studies have documented a reduced prevalence of Alzheimer's disease among users of nonsteroidal anti-inflammatory drugs (NSAIDs). It has been proposed that NSAIDs exert their beneficial effects in part by reducing neurotoxic inflammatory responses in the brain, although this mechanism has not been proved. Here we report that the NSAIDs ibuprofen, indomethacin and sulindac sulphide preferentially decrease the highly amyloidogenic Abeta42 peptide (the 42-residue isoform of the amyloid-beta peptide) produced from a variety of cultured cells by as much as 80%. This effect was not seen in all NSAIDs and seems not to be mediated by inhibition of cyclooxygenase (COX) activity, the principal pharmacological target of NSAIDs. Furthermore, short-term administration of ibuprofen to mice that produce mutant beta-amyloid precursor protein (APP) lowered their brain levels of Abeta42. In cultured cells, the decrease in Abeta42 secretion was accompanied by an increase in the Abeta(1-38) isoform, indicating that NSAIDs subtly alter gamma-secretase activity without significantly perturbing other APP processing pathways or Notch cleavage. Our findings suggest that NSAIDs directly affect amyloid pathology in the brain by reducing Abeta42 peptide levels independently of COX activity and that this Abeta42-lowering activity could be optimized to selectively target the pathogenic Abeta42 species.     

Viscero-somatic reflexes following distension of urinary bladder in cats: role of supraspinal neuraxis

Viscero-somatic reflexes have been studied by recording monosynaptic reflexes following distension of the urinary bladder in intact, decerebrate and spinal animals. It was observed that the viscero-somatic responses following bladder distension are inhibitory in nature and this inhibition was highest in decerebrates and least in spinal animals. The site of viscero-somatic interaction probably lies in the bulbar area (supraspinal) and spinal cord.     

42,000-molecular weight EGF receptor has protein kinase activity

The epidermal growth factor (EGF) receptor and other growth factor receptors have been shown to possess tyrosine-specific protein kinase activity. Before the demonstration of kinase activity in growth factor receptors, tyrosine kinases of molecular weight (MW) 60,000 (60K) were found to be encoded by the src oncogene and other oncogenes related to src. Our earlier work on intracellular processing of the EGF receptor, a 170,000-MW polypeptide, provided evidence for proteolytic separation of well defined structural domains, and suggested to us the possibility of separating functional domains by limited proteolysis. The isolation of such kinase domains should facilitate comparison of the receptor/kinase with other well characterized kinases including those of oncogene origin. We report here the identification of a catalytically functional 42K kinase derived proteolytically from the isolated human EGF receptor. This fragment, comparable in size to pp60src, carries the kinase ATP-binding site, and functions catalytically even after detachment from the EGF-binding site and the major autophosphorylation region.     

Neocortical transplants in the rat brain: an ultrastructural study

Electron microscopic analysis of neocortical transplants in the cerebellum of the host animals showed that the nerve cells, glial cells, and neuropil of the transplants were normal. These transplants showed anatomical integration with the host brain through various regions of interface. Neuropil interfaces were found to have a high density of synaptic profiles, and medullary interfaces had a very small number of synaptic profiles.     

Liposomes as immunological carriers for the preparation of antimannosyl antibodies

Antiserum was raised against an aminophenyl derivative of D-mannose grafted on to a liposomal surface. As characterized by immunodiffusion, quantitative precipitation and hapten inhibition, the antiserum was found to contain mannose specific antibodies in addition to antibodies against the aromatic phenyl group.