Changes in plasma thyroid hormones, luteinizing hormone (LH), estradiol, progesterone and corticosterone of laying hens during a forced molt

1. Circulating concentrations of iodothyronines, luteinizing hormone(LH), estradiol(E2), progesterone and corticosterone were measured in hens before, during, and after a forced molt induced by fasting. 2. Corticosterone increased at the onset of molt, peaked at the maximal molt and returned to pre- and post-molt levels. LH, E2 and progesterone declined during the molt, and the decline was coincident with the cessation of egg production. 3. Thyroxine(T4), triiodothyronine (T3) and reverse triiodothyronine(rT3) increased during the molt. The increases of T4 and T3 were not abolished even if the forced molt was conducted in mild weather.     

The spread of somatosensory-evoked potentials within the nervous system

Four thalamic and cortical recordings were carried out in 5 patients. The thalamic-evoked potentials were typical and revealed a triphasic complex, but their latencies showed a relatively high standard deviation. They could be divided into two groups according to their latencies, both of which had low SD. These data suggested that there could be two types of latency of thalamic SEP, because the 4 patients' body sizes were very similar. More detailed surface, cortical and depth recordings are needed to resolve these questions.     

Isolation of serum chylomicrons prior to density gradient ultracentrifugation of other serum lipoprotein classes

A method for the removal of serum chylomicrons before density gradient ultracentrifugation of the other serum lipoproteins using an SW 41 swinging bucket rotor is presented. In a preliminary spin, the chylomicrons with an Sf greater than 400 X 10(-13) s float to the top of the gradient, whereas the other lipoproteins are retained in the infranatant fraction. After removal of the chylomicrons, the other serum lipoproteins are subsequently fractionated by isopycnic density gradient ultracentrifugation. Analysis of the separated lipoprotein fractions suggested that this procedure permits isolation of a chylomicron fraction consisting solely of chylomicrons but that the very low density lipoprotein fraction subsequently isolated also contains chylomicrons or chylomicron remnants with an Sf less than 400 X 10(-13) s, and that there is considerable overlap in flotation rate and particle size of very low density lipoproteins and chylomicrons.     

Characterization of messenger RNA from epimastigotes and metacyclic trypomastigotes of Trypanosoma cruzi

The cell-free translation products of polyribosomal and post-polyribosomal mRNAs from the non-infective epimastigotes and the infective metacyclic trypomastigotes of the parasitic protozoan Trypanosoma cruzi were compared by two-dimensional polyacrylamide gel electrophoresis. The result show that although many polypeptides are conserved, quantitative and qualitative differences are observed between both differentiation stages. The results also indicate the existence of post-polyribosomal mRNAs in equilibrium with polyribosomal counterparts. The immunoprecipitation of the in vitro synthesized polypeptides with chagasic human serum and the serum raised against an 85-kDa glycoprotein (P2-WGA), potentially involved in the process of T. cruzi penetration into mammalian cells, shows that while the chagasic serum recognizes the same 72-kDa, 68-kDa and 46-kDa polypeptides in both differentiation stages, the anti-P2-WGA serum immunoprecipitates a single 48-kDa polypeptide from in vitro translation products of metacyclic trypomastigotes.     

Reversed-phase high-pressure liquid chromatography of arachidonic acid metabolites formed by cyclooxygenase and lipoxygenases

High-pressure liquid chromatography is required to resolve the complex mixtures of arachidonic acid metabolites synthesized by many tissues. We have investigated some of the factors which affect the retention times of these substances in reversed-phase HPLC on columns of 5-micron octadecylsilyl silica. There are considerable differences in selectivity between mobile phases based on methanol and those based on acetonitrile, the latter being much better for cyclooxygenase products. The chromatographic behavior of peptidoleukotrienes (LTC4, LTD4, and LTE4) is quite different from that of other arachidonic acid metabolites which do not contain amino acids. Addition of phosphoric acid to the mobile phase results in very long retention times for peptidoleukotrienes. Very low concentrations of trifluoroacetic acid have effects similar to that of phosphoric acid, but as its concentration is raised, the retention times of peptidoleukotrienes decrease, whereas those of other arachidonic acid metabolites are unaffected. Changing the concentration of acetonitrile in the mobile phase also affects the retention times of peptidoleukotrienes differently from those of other metabolites. This information has been used to devise simple linear gradients which separate most of the major cyclooxygenase and lipoxygenase products of arachidonic acid metabolism.     

Vaccination of mice against murine coccidiosis by ingestion of surface proteins of Eimeria falciformis incorporated in liposomes

Proteins are released from the surface of sporozoites of Eimeria falciformis during their in vitro incubation in a detergent solution. Some of these proteins reacted with antibodies from infected mice and specifically stimulated the proliferation of mesenteric lymph node cells of these mice. Oral immunization of mice with liposome encapsulated sporozoite surface antigens protected mice against a challenge infection. Two proteins (M.W. 27 and 180 K) induced an antibody synthesis in these vaccinated mice.     

Growth inhibitory effects of 5-aza-2'-deoxycytidine in HL-60 promyelocytic leukemia cells resistant to differentiation induction

In the original HL-60 cells (HL-60-S) and an HL-60 subline (HL-60-R) respectively susceptible and resistant to induction of differentiation by retinoic acid or dimethyl sulfoxide, 5-aza-2'-deoxycytidine inhibited growth equally but induced differentiation to a greater extent in HL-60-S. Flow cytometry showed that 5-aza-2'-deoxycytidine produced in both HL-60 lines an increased proportion of cells in G2+M rather than G0/G1 as with retinoic acid. 5-aza-2'-deoxycytidine may have a differentiation-inducing effect in HL-60 provided cells have the competence to differentiate, indicating the importance of an alternate mechanism of action.     

Changes in glycosylated haemoglobin after poor control in insulin-dependent diabetics.

Glycosylated haemoglobin (HbA1) was measured in seven insulin-dependent diabetic patients before, during, and after a seven-day period of monitored poor control. There was considerable individual variation in the pattern and degree of change in HbA1 concentration induced by poor control and the time when it occurred. Greater increases in HbA1 were seen during the period of metabolic derangement than in the subsequent two months. More information is required before HbA1 estimations are widely used clinically to monitor control in individual diabetics.