Transthyretin Pro55, a variant associated with early-onset,aggressive, diffuse amyloidosis with cardiac and neurologic involvement

Summary Mutations in the protein transthyretin cause amyloidosis involving the heart, peripheral nerves, and other organs. A family from West Virginia developed an unusually aggressive form of widespread transthyretin amyloidosis. Single-strand conformation polymorphism analysis revealed a variant in the transthyretin gene, which was found on sequencing to be a TC transversion at position 2 of codon 55, corresponding to a Leu Pro substitution. The variant sequence was confirmed by restriction analysis and polymerase chain reaction (PCR)-primer introduced restriction analysis.     

Beta-adrenoceptors in human airway tissue: relationship between functional responsiveness and receptor number.

Functional organ bath experiments and radiolabelled ligand binding studies were used to investigate the relationship between beta-adrenoceptor-mediated relaxation and the total number of beta-adrenoceptors in human lung parenchymal tissue and bronchial tissue. Sensitivity to the beta-adrenoceptor agonist isoprenaline (pD2) varied almost 10-fold (pD2 values 6.00 to 6.85) for lung parenchymal preparations and 35-fold for bronchial preparations (pD2 values 6.16 to 7.67) between patients. The total number of [3H] DHA labelled beta-adrenoceptors (Bmax) varied almost 6-fold for lung parenchymal membrane preparations (Bmax 164 to 936 fmol/mg protein) and less than 2-fold for bronchial tissue membrane preparations (Bmax 188 to 342 fmol/mg protein) between patients. Comparison of sensitivity to isoprenaline and beta-adrenoceptor number for lung parenchymal tissue from the same patient demonstrated a negative correlation (r = -0.80 [95% confidence intervals: -0.13, -0.96], 6 d.f., P less than 0.05), suggesting that beta-adrenoceptor-mediated sensitivity of lung parenchymal tissue is inversely related to the number of beta-adrenoceptors. However, there was an absence of correlation between sensitivity to isoprenaline and beta-adrenoceptor number in bronchial tissue from the same patient. Thus, the findings of the present study do not support the possibility of a direct relationship between the beta-adrenoceptor-mediated responsiveness and the beta-adrenoceptor number of human airway preparations.     

A semiempirical study of the prototropic tautomerism of hypoxanthine

The total and relative energies, bond order matrices and localized MOs for the eight possible tautomers of hypoxanthine (HYP) have been calculated, with full geometry optimization, using both AM1 and MNDO methods. The AM1 relative energies show that HYP(9,1), HYP(7,1) and HYP (9,10) are the predominant species at room temperature, the two former being in larger concentration that the latter. The calculated IR spectra for these species agree well with the reported spectrum in an isolated matrix, which has been interpreted in terms of the presence of these three tautomeric forms. The MNDO method does not predict the right order, and the more stable tautomer would be HYP(9,10). The calculated structure for the HYP(9,1) species shows that the molecule is essentially planar. The bond distances compare well with those of hypoxanthine hydrochloride and guanine and also correlate well with the calculated bond orders. The proton affinities for the three more stable tautomers have also been calculated. For HYP(9,1) the prefered site of protonation is N7, whereas for HYP(7,1) the protonation occurs rather at N9. These results agree well with¹⁵N and¹³C NMR studies in DMSO.     

Cytochrome P450s in the guinea pig adrenal that are immunologically similar to liver forms: estrogen suppression explains male-female differences

Several cytochrome P450s have been identified in guinea pig adrenal microsomes which are distinct from the known steroidogenic P450s, c17 and c21, and are immunochemically related to cytochrome P450s found in liver. One, a 52 K protein related to P450 I (CYP1), occurs almost exclusively in males, is localized to the inner zone, and is suppressed by ACTH. Its levels correlate with microsomal capacity for xenobiotic metabolism. The others, related to P450s II and III (CYP2 and 3), are more predominant in males, but not exclusive to them, are found in both the inner and outer zones, and are not suppressed by ACTH. Their functions remain to be elucidated. The male predominance of the CYP1-related protein has recently been shown to be due to suppression of the protein in females by estrogen. To determine if estrogen is also involved in the regulation of the CYP2-related proteins, ovariectomized and sham-operated animals were treated with a long-acting estrogen, estradiol valerate, or with the vehicle alone. These P450s reached male levels in ovariectomized females treated only with the vehicle. Their enhanced levels were suppressed by treatment with estrogen. Estrogen treatment also suppressed the levels of the P450s seen in sham-operated females. Endogenous estrogen produced similar effects. In hemi-ovariectomized females the contralateral ovary hypertrophied, a state in which estrogen levels would be maintained or increased. In these females no increase occurred in the immunodetectable P450s. In normal females, estrogen levels are low in prepubertal animals, rise at the time of puberty and drop again after ovarian cycling is completed. The CYP2-related proteins were present in adrenal microsomes of prepubertal females, but were suppressed after puberty. On the other hand, post-estrous females, in whom estrogen levels would be low, acquired male levels of these proteins in their adrenal microsomes. P450c17 and P450c21, as well as 3β-hydroxysteroid dehydrogenase, were not affected by surgery or estrogen. Taken together, these experiments indicate that suppression by estrogen in females can account, in large part, for the predominance of several immunochemical homologs of liver P450s in adult male guinea pig adrenals.     

Transient presence and functional interaction of endogenous GABA and GABAA receptors in developing rat optic nerve.

GABA (gamma-aminobutyric acid) is a major inhibitory synaptic neurotransmitter with widespread distribution in the central nervous system (CNS). GABA can also modulate axonal excitability by activation of GABAA receptors in CNS white matter regions where synapses and neuronal cell bodies are not present. Studies on cultured glia cells have revealed the synthesis of GABA in rat optic nerve O-2A progenitor cells that give rise to oligodendrocytes and type 2 astrocytes in vitro. We report here that: (i) GABA is detected by immuno-electron microscopy in intact rat optic nerve and is localized to glia and pre-myelinated axons during the first few weeks of postnatal development, but is markedly reduced or absent in the adult; and (ii) neonatal optic nerve is depolarized by GABAA receptor agonists or by the inhibition of GABA uptake. These results demonstrate the presence of functional GABAA receptors, and GABA uptake and release mechanisms in developing rat optic nerve, and suggest that excitability of developing axons can be modulated by endogenous neurotransmitter at non-synaptic sites.     

Cellularity of organs in mature rams of different breeds

The relative importance of cell number and cell size in determining the mass of 16 organs and tissues in mature rams of six different breeds was studied through estimation of organ deoxyribonucleic acid (DNA) content. The mean fleece-free empty body weight (FFEBW) ranged from 54.6 +/- 0.3 kg for Camden Park Merinos to 76.7 +/- 1.6 kg for Strong Wool Merinos. For all organs, mass increased with FFEBW, but the relationship was significant across all sheep for only eight organs (blood, kidney, liver, abomasum, vastus lateralis muscle, skin, perirenal fat and triceps muscle). There were significant differences between breeds in the mass of 11 organs. With four (heart, rumen reticulum, small intestine and testicular fat) this difference was independent of breed differences in FFEBW, whereas with another four (kidney, abomasum, vastus lateralis muscle and skin), it was closely related to FFEBW. Breed differences in the mass of the remaining three organs (blood, liver and perirenal fat) were partly related to FFEBW and partly breed specific. Blood mass increased with FFEBW across all animals, but, within a breed, it declined as FFEBW increased. The increase in the mass of perirenal fat with FFEBW was significantly greater within a breed than between breeds. Cell number increased significantly with the mass of all organs except blood and brain. There were between-breed differences in the number of cells in seven organs (liver, heart, rumen reticulum, abomasum, small intestine, vastus lateralis muscle and skin), which, except for heart, were attributable to between-breed differences in organ mass. With heart, the increase in cell number with organ mass within a breed was greater than across all breeds. Cell size was significantly related to organ mass only with vastus lateralis muscle, spleen, perirenal fat and liver. The relationship for vastus lateralis muscle and spleen was negative, indicating that cells were smaller in larger organs. There were differences between breeds in cell size for heart, vastus lateralis and triceps muscles. These differences for heart and triceps muscle were breed specific, whereas for vastus lateralis muscle it was attributed to breed differences in organ weight. There was a 30-fold range in mean cell size across organs, with adipose tissue having the largest cells, muscle tissue intermediate and visceral tissues the smallest. In general, organ mass is positively related to FFEBW. Cell number, not cell size, is largely responsible for differences in organ mass between mature sheep of different breeds.     

Organosolv pretreatment for enzymatic hydrolysis of poplars: I. Enzyme hydrolysis of cellulosic residues

Aspen (Populus tremuloides) and black cottonwood (Populus trichocarpa) organosolv pulps produced in a wide range of solvent composition (between 30 and 70% by volume of methanol) and catalysts (H(2)SO(4) and H(3)PO(4)) such that the cooking liquor pH 相似文献   

A comparison of techniques for isolation of the outer membrane proteins of Haemophilus influenzae type b

We compared several rapid techniques used for extraction of outer membrane proteins from gram-negative enteric bacteria to Haemophilus influenzae type b. After lysis of cells with a French press, the inner and outer membranes were separated by isopycnic centrifugation. Each membrane was identified by density, morphology, enzymatic activity, and susceptibility to solid-phase iodination of intact cells. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, we identified 10 polypeptides which were enriched in the outer membrane band compared to the inner membrane band. Using these proteins, we compared the polypeptide pattern of outer membranes with that obtained by (1) selective solubilization with sodium dodecyl-beta-D-maltoside, octyl-beta-D-glucopyranoside, Triton X-100, sodium, or cholamidopropyl dimethylaminopropanesulfonate; (2) extraction with chaotropic agents and heat; and (3) differential centrifugation of vesicles shed during transition from log growth phase to stationary growth phase. There were definable differences between the polypeptide pattern of membranes obtained with each rapid technique compared to the polypeptide pattern of isolated outer membranes. The polypeptide pattern of lithium extracts and the Triton X-100 insoluble fractions of total membranes most closely approximated the polypeptide pattern of isopycnically isolated outer membranes. Depending on the outer membrane protein sought, one of these rapid techniques can be utilized when a rapid method of outer membrane protein isolation is required.     

Thermal ecology of Pieris butterflies (Lepidoptera: Pieridae): a new mechanism of behavioral thermoregulation

Summary I document a new mechanism for behavioral thermoregulation, not previously described in animals, called reflectance basking. This behavior, described here for Pieris butterflies, involves the use of the wings as solar reflectors that reflect solar radiation onto the body to increase body temperature. Results show that Pieris require thoracic (body) temperature. between 29° and 40° C in order to take off and fly, and achieve these elevated temperatures by basking. Diurnal patterns of population flight activity are closely correlated with patterns of body temperature during basking. Behavioral studies indicate that 1) Pieris orient to solar radiation, 2) they use thermoregulatory postures consistent with reflectance basking, and 3) they do not use the basking postures found in other Pierid butterflies (i.e., the Coliadinae). There are consistent differences in wing angles used in reflectance basking between Pieris in different subgenera. Results are discussed with respect to thermoregulation and wing color in other Pierid butterflies, and suggest that a re-evaluation of the functional significance of melanization in Pieris is needed.     

Chloroplasts in the epidermis of Sarracenia (the American pitcher plant) and their possible role in carnivory - An immunocytochemical approach

A photosynthetic apparatus is present in the epidermis of the bottom zone of the pitcher of Sarracenia purpurea L. ssp. purpurea. This has been demonstrated using conventional light and electron microscopy, as well as fluorescent and immunohistochemical techniques. Red intrinsic fluorescence by these chloroplasts indicates photochemical activity. Antibodies against the coupling factor of chloroplast ATPase and against the subunits of ribulose-bis-phosphate-carboxylase were bound to the epidermal chloroplasts. This has been visualized using a ferritin-isothiocyanate labeled second antibody. These results unequivocally prove the existence of the two main proteins which are associated with the photophosphorylation (membrane protein) and carbon dioxide fixation (stromal protein). The possible implication of this system to interrelationships between the carnivorous plant and aquatic insects inhabiting its leaves is discussed.