The recent increase in Atlantic hurricane activity: causes and implications.

The years 1995 to 2000 experienced the highest level of North Atlantic hurricane activity in the reliable record. Compared with the generally low activity of the previous 24 years (1971 to 1994), the past 6 years have seen a doubling of overall activity for the whole basin, a 2.5-fold increase in major hurricanes (>/=50 meters per second), and a fivefold increase in hurricanes affecting the Caribbean. The greater activity results from simultaneous increases in North Atlantic sea-surface temperatures and decreases in vertical wind shear. Because these changes exhibit a multidecadal time scale, the present high level of hurricane activity is likely to persist for an additional approximately 10 to 40 years. The shift in climate calls for a reevaluation of preparedness and mitigation strategies.

Fever of unknown origin in patients undergoing chemotherapy.

Drug fever refers to a febrile response to a drug, and its clinical picture often resembles an allergic reaction or infection. The fever most commonly occurs 7-10 days after drug administration, persists as long as the drug is continued, and disappears soon after stopping the drug (Tabor, 1986). The risks and benefits of continuing a drug that causes fever must be evaluated for every patient who experiences drug fevers. Quality-of-life issues arise for patients who experience them despite the concurrent use of steroids. Recognizing drug fever is of great clinical importance. If drug fever is not recognized, patients may be subjected to prolonged hospitalizations and unnecessary testing and medications (Johnson & Cunha, 1996). Oncology nurses play an important role in the early recognition of drug fever.

Effect of trehalose and sucrose on the hydration and dipole potential of lipid bilayers.

The water activity in dimyristoylphosphatidylcholine (DMPC) decreases by 60% when the lipid is dehydrated in the presence of trehalose concentrations higher than 0.02 M. In contrast, sucrose in concentrations 10 times higher produced only a 20% decrease in the water activity in the sample. Titrations of a DMPC solution in chloroform yielded 14 water molecules per lipid when pure water was added and seven water molecules per lipid when the titration was done with 0.025 M trehalose. The same concentrations of sucrose produced a turbid solution, which made it impossible to quantify the number of water molecules per lipid. Lipid monolayers spread on an air/water interface showed a decrease from 480 mV in pure water to 425 mV in 0.1 M trehalose. However, the same concentrations of sucrose produced an increase of less than 100 mV. Results obtained with Fourier transform infrared spectroscopy (FTIR) under the same conditions denoted that trehalose binds to the carbonyl groups, while sucrose showed no specific binding. It is concluded that per lipid molecule, 11 of 14 water molecules can be replaced by three trehalose molecules. About four are displaced by changes in the water activity of the bulk solution, and seven by specific interactions with the phospholipids. In this last case, at least two of them are linked to the carbonyls, and this appears to be the cause of the decrease in the dipole potential of the membrane. In contrast, four sucrose molecules displace only three water molecules per lipid, with no effect on the dipole potential or the carbonyl groups.

Structural and biochemical modifications in parotid gland induced by fasting.

Structural, ultrastructural and biochemical modifications produced by fasting in the parotid gland of guinea pig, were studied. The highest storage of secretory granules was found in the apical cytoplasm after a 12 hour fasting period. The curve of soluble proteins showed that the highest storage of proteins in the parenchyma took place after a 10/12 hour fasting period. Amylase activity reached its highest point after a 10 hour fasting period. We suggest that granules stored in cellular cytoplasm after a 12 hour fasting period would have completed their maturation cycle.

The 5' flanking region of the pS2 gene contains a complex enhancer region responsive to oestrogens, epidermal growth factor, a tumour promoter (TPA), the c-Ha-ras oncoprotein and the c-jun protein.

Expression of the pS2 gene which is transcriptionally controlled by oestrogens in the breast cancer cell line MCF-7 is oestrogen independent in stomach mucosa. We show here that the level of MCF-7 cell pS2 mRNA can also be increased by the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). We further demonstrate, using transient transfection assays, that the -428 to -332 5' flanking sequence of the pS2 gene contains DNA enhancer elements responsive to oestrogens, TPA, EGF, the c-Ha-ras oncoprotein and the c-jun protein.

Estrogen-responsive element of the human pS2 gene is an imperfectly palindromic sequence.

Using chimeric recombinants transfected into HeLa cells and a transient expression assay, we demonstrate that the 5'-flanking region of the pS2 gene from position -428 to position -324 exhibits both constitutive and estrogen-inducible enhancer activity. The estrogen-inducible activity, but not the constitutive activity, was inhibited by antiestrogens. ICI 164,384 behaved as a pure antagonist, whereas hydroxytamoxifen was a partial agonist-antagonist. The estrogen-responsive element of the pS2 gene has been narrowed down by site-directed deletion mutagenesis to a 13-base-pair (position -405 to position -393) imperfectly palindromic sequence, which in isolation can confer estrogen inducibility to the heterologous rabbit beta-globin gene promoter. On the other hand, the sequences responsible for the constitutive enhancer activity are spread over the entire region.

Structure and function of the pS2 gene and estrogen receptor in human breast cancer cells.

The role of estrogen in the growth of human breast cancers has been investigated at two levels. First, we have studied the pS2 gene, whose transcription is stimulated by estrogen in the human breast cancer cell line, MCF-7. The pS2 gene product is a small, secreted polypeptide currently of unknown function, but with structural features similar to some growth factors. The expression of the pS2 gene has so far been detected only in MCF-7 cells and some breast cancer biopsies. Preliminary studies indicate that pS2 is a potential marker for hormone-dependent breast cancer. Ongoing studies will continue to focus on the implicated role of pS2 in the estrogen-mediated growth of breast cancers and its possible use as a marker for estrogen-dependent tumors. Second, we have analyzed the structure and function of the human ER. The receptor stimulates pS2 gene transcription by interacting with an ERE in the 5'-flanking region of that gene. A mutational analysis of the receptor protein has localized a DNA-binding domain, which determines target gene specificity, and a hormone-binding domain. These domains appear to be the only two regions of the receptor which are absolutely required for the transcription-activating function of the ER in transfection assays with reporter plasmids. The N-terminal region of the protein (regions A and B), which is necessary for increasing the efficiency of gene expression using the pS2 ERE, but not a vitellogenin ERE, may also play a role in transcription activation. Further progress in the characterization of the ER functional domains will require studies on target genes in a more physiological chromatin environment, as well as detailed physical analyses of receptor structure.

Characterization of the estrogen-induced pS2 protein secreted by the human breast cancer cell line MCF-7.

Our laboratory has reported previously the cloning of a complementary DNA termed pS2, corresponding to a messenger RNA (mRNA) whose synthesis is induced by estrogen in the human breast cancer cells MCF-7. Examination of the possible open reading frames of this complementary DNA has led to the prediction that the pS2 protein could be a secreted polypeptide of either 58 or 63 amino acids in length. Using a rabbit antiserum prepared against a synthetic peptide corresponding to the last 31 amino acids of the putative protein, we show that a protein with the expected migration during sodium dodecyl sulfate gel electrophoresis can indeed be immunoprecipitated from either the culture medium of MCF-7 cells grown in the presence of labeled amino acids or the in vitro translation products of MCF-7 poly(A) RNA enriched in pS2 mRNA. Furthermore, in vivo and in vitro differential amino acid labeling allows us to conclude that the mature pS2 protein is probably secreted as a 58 amino acid long peptide. Finally, we show that pS2 protein synthesis is induced in MCF-7 cells by estradiol and phenol red, but not by the antiestrogen tamoxifen, in keeping with our previous results demonstrating estrogen induction of pS2 mRNA synthesis.

Promoter region of the human pro-alpha 1(II)-collagen gene.

We have isolated a genomic clone containing the 5'-terminal portion of the human pro-alpha 1(II)-collagen gene. This clone, HC2C, contains 10 kb of the gene and 6 kb of 5'-flanking sequences. It was selected by cross hybridization using a [32P]DNA probe containing the promoter region of the rat alpha 1(II)-collagen gene. We have determined the nucleotide sequence of the first exon and of 400 bp upstream. There is considerable homology between this human sequence and the corresponding rat sequence. As in the rat, the first exon contains a 155-bp untranslated segment and a 85-bp sequence coding for the signal peptide and a part of the N-propeptide of type-II procollagen. The segment preceding the transcription initiation site contains a conserved 'ATATAA' element, and several similar G + C-rich stretches. As in the rat gene, no 'CAT' element is evident between -70 and -120. We also find the sequence 5'-GTGGTCAGA-3' reported as an enhancer element in both viral and cellular genes, located around -290 bp. A high degree of homology exists between the atypical rat and human promoter structures; however, such homology is absent among the alpha 1(I), alpha 2(I) and alpha 1(III) promoters, which suggests that the unique alpha 1(II) sequences may be related to the specific expression of the alpha 1(II)-collagen gene.

Isolation and partial characterization of genomic clones coding for a human pro-alpha 1 (II) collagen chain and demonstration of restriction fragment length polymorphism at the 3' end of the gene.

We have isolated two clones containing 19 kilobases (kb) of the human gene coding for a pro-alpha 1 (II) collagen chain from human lambda genomic DNA libraries. A 3' clone, HC2A, was selected by cross-hybridization with a cDNA clone containing sequences coding for the carboxy propeptide of chick type II procollagen. A second clone, HC2B, was obtained by screening the library with the 5' part of HC2A. The sequence analysis of exon 3 corresponding to the C propeptide reveals the presence of stretches of conserved nucleotides between the human and the chick type II procollagen genes. On Northern blots, the human collagen clone hybridizes strongly to a 5.5-kb RNA for the rat type II procollagen chain. Finally, studies of genomic DNAs from normal individuals reveal the presence of a HindIII and a BamHI polymorphic site at the 3' end of the gene.

Isolation of cDNA and genomic DNA clones encoding type II collagen.

A cDNA library constructed from total chick embryo RNA was screened with an enriched fraction of type II collagen mRNA. Two overlapping cDNA clones were characterized and shown to encode the COOH propeptide of type II collagen. In addition, a type II collagen clone was isolated from a Charon 4A library of chick genomic fragments. Definitive identification of the clones was based on DNA sequence analysis. The 3' end of the type II collagen gene appears to be similar to that of other interstitial collagen genes. Northern hybridization data indicates that there is a marked decrease in type II collagen mRNA levels in chondrocytes treated with the dedifferentiating agent 5-bromodeoxyuridine. The major type II collagen mRNA species is 5300 bases long, similar to that of other interstitial collagen RNAs.

Diffuse structural alterations in cell membranes of spontaneously hypertensive rats.

Plasma membranes from heart, nerve endings, and liver were compared in 3-week-old male spontaneously hypertensive rats from the Okamoto substrain (SHR) and normotensive Wistar/Kyoto control rats (WKY) [systolic blood pressure 105 +/- 4 and 95 +/- 4 mm Hg, respectively (1 mm Hg = 133 Pa)] according to two criteria: calcium binding at physiological intracellular concentrations and polarization of an embedded fluorescent probe, 1,6-diphenyl-1,3,5-hexatriene. Whatever the tissue of origin, the density of high-affinity calcium binding sites was lower in SHR than in WKY plasma membranes, and the polarization of diphenylhexatriene fluorescence was constantly higher in SHR than in WKY membranes. These membrane abnormalities are similar to those previously described in the erythrocyte membrane from SHR. The presence of diffuse structural alterations in cellular membrane from young spontaneously hypertensive rats when blood pressure is still in the normotensive range suggests a genetic origin. Such inherited abnormalities may by themselves participate in the rise in blood pressure.

High-affinity calcium binding in rat synaptosomal plasma membranes: decrease in young, genetically hypertensive rats.

A large number (about 4--5 nmol/mg of protein) of high-affinity (apparent dissociation constant at 37 degrees C: KD37 degrees C = 5 x 10(-8) M) calcium binding sites was characterized in synaptosomal membrane fractions enriched in plasma membranes that were isolated from rat brain. These sites were studied simultaneously in membranes from spontaneously hypertensive young rats (SHR) and their normotensive controls. No difference was observed between whole synaptosomes from these two substrains. However, plasma membrane-enriched fractions from SHR exhibited a reduced calcium binding capacity without a significant change in affinity. This decrease which averaged 15--20% was not due to any variation in the accessibility of calcium to its binding sites, as similar results were obtained in the presence of the calcium ionophore A23187. The reduction found in calcium binding is very similar to that previously described in erythrocyte membranes. It is envisaged that such an abnormality at nerve endings might play a role in the pathogenesis of genetic hypertension.

Analysis of calcium handling in erythrocyte membranes of genetically hypertensive rats.

Calcium handling by erythrocyte membranes was compared in genetically hypertensive (SHR) and normotensive (WKR) rats by direct measurement of calcium binding, passive influx, and adenosine triphosphate (ATP)-dependent extrusion. The SHR erythrocyte membranes exhibited the following abnormalities: 1) the binding capacity of the high affinity Ca2+-binding sites located on the inner side of the membrane was 0.84 +/- 0.07 nmole/mg protein compared with 1.17 +/- 0.08 nmole/mg protein in WKR, 2) ATP-dependent Ca2+ extrusion, measured as the Ca2+ influx into inside-out vesicles, was also lower than the WKR, as was the La3+ -sensitive, Ca2+ -dependent hydrolysis, indicating reduced activity of the calcium pump; 3) the passive calcium influx into ATP-depleted red blood cells was slightly accelerated. these abnormalities in Ca2+ binding and transport probably enhanced intracellular Ca2+ concentration, and were observed under both prehypertensive an hypertensive conditions, in 3-week-old and adult SHR respectively. Similar membrane defects in excitable cells may help to explain the pathogenesis of hypertension, since they may increase vascular tone and/or catecholamine release.

Calcium binding alteration in plasma membrane from various tissues of spontaneously hypertensive rat.

Calcium binding properties of plasma membrane enriched fractions from various tissues were studied in young spontaneously hypertensive rats (SHR) and their normotensive controls (WKY). In all tissues tested (heart, liver, nerve endings, erythrocytes), high affinity calcium binding sites were characterized. Their KD values were in the range of the cytosolic free calcium concentration : (10(-8)-10(-7)). Whatever the tissue, plasma membrane enriched fraction from SHR exhibited a reduced calcium binding capacity but no significant change in affinity. This decrease which averaged 15-25% was also observed in the presence of the calcium ionophore A23187 and thus does not result from a modified accessibility of calcium to its binding sites. It is suggested that this abnormality may be of genetic origin and is possibly implicated in the pathogenesis of hypertension.