Polymorphonuclear leucocyte function in hypothyroidism.

The quantitative nitroblue-tetrazolium test demonstrated that polymorphonuclear leucocytes from patients with hypothyroidism reduced the dye less well than leucocytes from euthyroid persons. The ability of these cells to ingest and kill staphylococci were unimpaired. The abnormality of the nitroblue-tetrazolium test in hypothyroid patients was corrected after their treatment with thyroxine.     

An immunologically related family of apolipoproteins associated with triacylglycerol storage in the Cruciferae

The major apolipoproteins associated with oil-storage bodies have been isolated from the mature seeds of six different species of the family Cruciferae. The apolipoproteins were all of molecular mass 19-20 kDa. They were highly abundant in mature seed tissue, accounting for up to 20% total seed proteins, and were localized exclusively on the membranes of oil-storage bodies. Antibodies were raised in rabbits and mice against the six purified apolipoproteins. In each case, the antibodies specifically recognized 19-20 kDa polypeptides on immunoblots of total seed proteins from 15 different species of the Cruciferae. The extent of the immunological cross-reactivity among the six purified seed apolipoproteins of the Cruciferae was investigated quantitatively using enzyme-linked immunosorbent assay. Very high levels of cross-reactivity were obtained, in contrast to a complete lack of cross-reactivity observed when the major seed apolipoprotein of a non-crucifer, Glycine max, was assayed. Peptide mapping studies showed that the different crucifer seed apolipoproteins gave rise to similar proteolytic cleavage products following treatment with Staphylococcus aureus V8 protease, Lysobacter enzymogenes Lys-C endoprotease, and trypsin. The patterns of immunogenic proteolytic cleavage products of the different apolipoproteins were also similar. We propose that there is a family of abundant 19-20 kDa apolipoproteins in mature seeds of oil-bearing Cruciferae. These apolipoproteins are all major components of the membranes of oil-storage bodies. The apolipoproteins are therefore very closely related with respect to their structure, function, and immunological properties.     

SEASONAL AND DIURNAL TRENDS OF CHORUSING HUMPBACK WHALES WINTERING IN WATERS OFF WESTERN MAUI

A portable data logger controlled by a Tattletale 7 microcontroller was used to record humpback whale choruses during the 1998 humpback whale winter season in Hawaii. The data logger sampled the sounds for four minutes every half hour using a digitizing rate of 2 kHz, and the data were stored on a hard disk. The results between January and April showed a peak in the sound pressure level between mid-February and mid-March. This peak of approximately 120 dB re 1 μPa coincided with the peak in the number of whales sighted by aerial survey on 7 March 1998. The choruses had spectral peaks at 315 Hz and 630 Hz. Some of the sounds at 630 Hz were second harmonics of the 315 Hz peak and others were not. The data also indicated a diurnal pattern in the sound pressure level, with levels at night significantly louder than the daytime levels. The sound levels began to increase during sunset and remained relatively high until sunrise, when they progressively decreased to a minimum. The nighttime peak occurred within an hour before and after midnight, and the daytime minimum occurred between 1100 and 1500. That more humpback whales appear to sing at night may reflect a switch to sexual advertisement as the primary male mating strategy at this time. It may also indicate that daylight and vision play key roles in the formation of competitive groups. It is suggested that the relative number of humpback whales in a given locale may be estimated by monitoring changes in sound pressure levels.     

Influence of a diet rich in fish oil on blood pressure, body weight and cardiac hypertrophy in spontaneously hypertensive rats

The effects of a diet rich in fish oil on arterial blood pressure, body weight, left ventricular weight and heart rate have been investigated in 8 month old spontaneously hypertensive male rats (SHR) as compared to age-matched hypertensive controls. A diet containing 10% fish oil decreased blood pressure by about 40 mmHg within 20 days of starting the experiment, and this effect persisted over the observation period of 80 days. Permitting the animals free access to food, the body weight of the diet group increased by 25%. The degree of hypertrophy as evaluated by relating left ventricular weight to tibial length was significantly reduced (10%) in the diet fed group. Heart rate was increased by 53%. The study demonstrates that a diet rich in fish oil can lower arterial blood pressure over several weeks without a recognizable loss in function despite a considerable increase in body weight. It can be assumed that a more marked regression of left ventricular hypertrophy is counteracted by a reflex increase in sympathetic efferentation to the heart.     

Phosphorylation of centromeric histone H3 variant regulates chromosome segregation in Saccharomyces cerevisiae

The centromeric histone H3 variant (CenH3) is essential for chromosome segregation in eukaryotes. We identify posttranslational modifications of Saccharomyces cerevisiae CenH3, Cse4. Functional characterization of cse4 phosphorylation mutants shows growth and chromosome segregation defects when combined with kinetochore mutants okp1 and ame1. Using a phosphoserine-specific antibody, we show that the association of phosphorylated Cse4 with centromeres increases in response to defective microtubule attachment or reduced cohesion. We determine that evolutionarily conserved Ipl1/Aurora B contributes to phosphorylation of Cse4, as levels of phosphorylated Cse4 are reduced at centromeres in ipl1 strains in vivo, and in vitro assays show phosphorylation of Cse4 by Ipl1. Consistent with these results, we observe that a phosphomimetic cse4-4SD mutant suppresses the temperature-sensitive growth of ipl1-2 and Ipl1 substrate mutants dam1 spc34 and ndc80, which are defective for chromosome biorientation. Furthermore, cell biology approaches using a green fluorescent protein–labeled chromosome show that cse4-4SD suppresses chromosome segregation defects in dam1 spc34 strains. On the basis of these results, we propose that phosphorylation of Cse4 destabilizes defective kinetochores to promote biorientation and ensure faithful chromosome segregation. Taken together, our results provide a detailed analysis, in vivo and in vitro, of Cse4 phosphorylation and its role in promoting faithful chromosome segregation.     

Ring chromosome 15: phenotype, Ag-NOR analysis, secondary aneuploidy, and associated chromosome instability

Cytogenetic analysis of a 15 month old girl evaluated for severe developmental delay and acral skeletal hypoplasia revealed a predominant 46,XX,r(15) karyotype. Prophase banding analysis showed minimal deletion of the ring chromosome (breakpoints p12 and q26), while silver staining showed it to have an active nucleolus organizing region, multiple abnormal secondary configurations, and decreased satellite association. Although there was no spontaneous instability in the rest of the karyotype, gentian violet-induced chromosome breakage was significantly increased. The rate of spontaneous sister chromatid exchange was not elevated. Cellular mosaicism for chromosome 15 aneuploidy most likely accounts for the patient's phenotypic abnormalities.     

The actions of prostaglandins I2 and E2 on arrhythmias produced by coronary occlusion in the rat and dog.

Prostaglandins E2 and I2 were compared with known antiarrhythmics for their actions against arrhythmias produced by occlusion of the left anterior descending coronary artery in the anaesthetised rat while PGI2 was also examined in the dog. PGI2 in the dog suppressed early arrhythmias produced during occlusion but did not influence those produced by occlusion-release or those occurring 24 hours after a permanent occlusion; none of the A,B,C or D series prostaglandins tested markedly reduced 24 hour arrhythmias. In the rat PGE2 was antiarrhythmic against early occlusion arrhythmias (30 minutes occlusion) in a dose related manner (infusions of 1-4 microgram/kg/min) whereas PGI2 infusions potentiated the arrhythmogenic effect of occlusion. PGE2 was as effective an antiarrhythmic as 10mg/kg Org. 6001 which was more effective in this test situtation than dl-propranolol. No obvious mechanisms for the actions of PGE2 or PGI2 were apparent although both agents lowered blood pressure and reduced the size of the occluded zone produced by ligation.