Anencephaly in trisomy 18 associated with elevated alpha-1-fetoprotein in amniotic fluid

Summary Elevated levels of alpha-1-fetoprotein (AFP) were found in the amniotic fluid of a 36-year-old woman in the 15th week of gestation. Because of this and the results of repeated ultrasonography, abortion was induced. An anencephalic fetus with trisomy 18 was delivered. The possible correlation among neural-tube defects, chromosomal abnormalities, and level of AFP is discussed.     

Recovery,structure, and function of dog granulocytes after freeze-preservation with dimethylsulfoxide

The recovery, structure and function of dog granulocytes were determined before and after freeze-preservation. Leucocytes were isolated from defibrinated or anti-coagulated whole blood and subsequent erythrocyte sedimentation on a column of 2:1 dextran (6%)-isopaque (33.9%). Granulocytes isolated by these procedures were examined for changes in O₂ consumption associated with phagocytosis, in vitro directed migration (chemotaxis), bactericidal activity, and ultrastructure before and after freezing. Granulocytes were frozen in DMSO (7.5%) and autologous serum or HBSS-minus and 20% autologous serum at the rate of ?1 °C/min to ?80 °C and stored in liquid N₂ vapor.After freeze-preservation, O₂ consumption associated with phagocytosis was decreased by 54 and 64% for granulocytes isolated from defibrinated or from ACD-anticoagulated blood, respectively. Bactericidal activity is only slightly depressed in samples from either isolation method after freeze-preservation when compared to the prefreeze controls, but granulocytes isolated from defibrinated blood are significantly less effective in killing bacteria than those from ACD-anticoagulated blood. Chemotactic response after freeze-preservation was completely inhibited in granulocytes isolated from defibrinated blood. Exposure of granulocytes to ACD inhibited chemotaxis prior to freezing, but the granulocytes responded chemotactically after freeze-thaw and additional washing. The ultrastructure of granulocytes observed before and after freeze-thaw was similar for cells isolated by both methods. However, nuclear, cytoplasmic, and granular changes observed were slightly greater in granulocytes isolated from defibrinated blood. Dog granulocytes isolated by either method withstood freeze-preservation in DMSO to a degree not previously reported.It is concluded that dog granulocytes freeze-preserved by these methods are functional in vitro, but that phagocytic, directed migration, and bactericidal functions and ultrastructure are impaired to different degrees, according to the method of isolation and preparation for storage. These results indicate the need for continued investigation on the effects of storage variables on the preservation of granulocytes.     

Classification and identification of bacteria by Fourier-transform infrared spectroscopy.

This study describes a computer-based technique for classifying and identifying bacterial samples using Fourier-transform infrared spectroscopy (FT-IR) patterns. Classification schemes were tested for selected series of bacterial strains and species from a variety of different genera. Dissimilarities between bacterial IR spectra were calculated using modified correlation coefficients. Dissimilarity matrices were used for cluster analysis, which yielded dendrograms broadly equated with conventional taxonomic classification schemes. Analyses were performed with selected strains of the taxa Staphylococcus, Streptococcus, Clostridium, Legionella and Escherichia coli in particular, and with a database containing 139 bacterial reference spectra. The latter covered a wide range of Gram-negative and Gram-positive bacteria. Unknown specimens could be identified when included in an established cluster analysis. Thirty-six clinical isolates of Staphylococcus aureus and 24 of Streptococcus faecalis were tested and all were assigned to the correct species cluster. It is concluded that: (1) FT-IR patterns can be used to type bacteria; (2) FT-IR provides data which can be treated such that classifications are similar and/or complementary to conventional classification schemes; and (3) FT-IR can be used as an easy and safe method for the rapid identification of clinical isolates.     

Small and medium-angle X-ray analysis of bacterial lipoteichoic acid phase structure.

X-ray scattering analysis was performed on various types of bacterial lipoteichoic acid in solution. The X-ray data show that all samples investigated were characterized by a similar micellar ultrastructure (hydrophilic moiety on the outside) with a fatty acid chain conformation of the disordered, alpha-type at all temperatures between 5 degrees-53 degrees C. The size distribution of Staphylococcus aureus lipoteichoic acid micelles was sufficiently homogeneous to determine their size and some related molecular parameters by detailed small-angle X-ray scattering analysis. Nearly independent of the degree of D-alanine substitution and the ionic strength of the aqueous dispersion, an average micelle contained about 150 lipoteichoic acid molecules arranged in a spherical assembly with a diameter of about 22 nm, whereby the hydrophilic region occupied an outer shell of about 8.5 nm thickness. Based on the average chain length of lipoteichoic acid, it could be estimated that each glycerophosphate residue contributed by about 0.34 nm to the thickness of the hydrophilic shell as compared to a theoretical value of approximately 0.8 nm for a fully extended chain conformation, indicating a highly coiled conformation of the hydrophilic chain. The bearing of these findings on the properties of membrane-associated and secreted lipoteichoic acids is discussed.     

Complete cDNA and gene sequence of the developmentally regulated arylphorin of Calliphora vicina and its homology to insect hemolymph proteins and arthropod hemocyanins.

Two cDNA libraries were prepared from poly(A)+ RNA isolated from fat bodies of last instar larvae of the blowfly Calliphora vicina. The libraries were probed with a genomic clone containing the coding sequence for an arylphorin subunit. Two cDNA clones as well as the genomic clone were mapped and their nucleotide sequences were determined. This revealed the presence of an open reading frame corresponding to a polypeptide with 759 amino acid residues. The deduced primary structure of Calliphora arylphorin and hemolymph proteins of other insect species and arthropod hemocyanine show nearly 30% identity. Highly conserved regions could be also identified.     

Effect of cold environment on skeletal muscle mitochondria in growing rats

Summary Growing rats (4 weeks old) were kept for 3 weeks at 11° C and 24° C respectively. The cold-adapted animals showed a significantly higher oxygen consumption (64%). Volume density of subsarcolemmal and interfibrillar mitochondria as well as volume density of fat droplets were estimated in M. soleus and the diaphragm of both groups. In cold-adapted animals, the total volume of mitochondria was significantly increased by 24% in diaphragm and 37% in M. soleus. The volume of subsarcolemmal mitochondria was almost doubled in each muscle, but the volume of interfibrillar mitochondria did not change significantly. The surface of the inner mitochondrial membranes per unit volume of mitochondrion in M. soleus was significantly increased both in interfibrillar and subsarcolemmal mitochondria, whereas the surface of the outer mitochondrial membranes per unit volume of mitochondrion was increased only in the subsarcolemmal mitochondria. The volume of fat droplets in the diaphragm and M. soleus of cold adapted animals increased significantly by 62% and 150% respectively.     

Potentiation of postjunctional cholinergic sensitivity of rat diaphragm muscle by high-energy-phosphate adenine nucleotides

Summary The cholinergic sensitivity of rat diaphragm muscle, measured as the magnitude of depolarization responses to repetitive, iontophoretic pulses of acetylcholine (ACh) onto neuromuscular endplates, is increased by addition of ATP to the perfusion medium. Depolarization responses begin to increase within the first min after addition of 10mm ATP and plateau at 60% above control levels (mean value) after 4 to 6 min. Neither the magnitude nor the time course of the potentiations corresponds to changes in resting potential or membrane resistance. Other nucleotides are equally or less effective at the same concentration: ATP-ADP>UTP>AMP=GTP (=no added nucleotide control) The duration of the individual ACh responses does not increase during continuous exposure to the active nucleotides for up to 15 min except when the muscle is pretreated with eserine.Mild enzymatic predigestion of the muscle with collagenase and then protease, increasing the availability of the postjunctional membrane to bath-applied drugs, decreases the variability and increases the magnitude of the potentiation to a given dose of ATP. The dose-response curve for ATP is then more than half-maximal at 1mm and the ranking of the other nucleotides relative to ATP is the same as without predigestion.There is an optimum Ca⁺⁺ concentration for the potentiation between zero and 2mm: potentiation is enhanced in Ca⁺⁺-free medium, partially blocked in twice-normal Ca⁺⁺ medium, and totally blocked in Ca⁺⁺-free medium 10 min after a 5 min exposure to 2.5mm EGTA. The similar Ca⁺⁺ dependence of ACh receptor activation in the absence of added nucleotide suggests that ATP directly facilitates receptor activation by ACh. This facilitory action could be one of the physiological roles for the ATP released from stimulated phrenic nerve.     

Potentiation of postjunctional cholinergic sensitivity of rat diaphragm muscle by high-energy-phosphate adenine nucleotides.

The cholinergic sensitivity of rat diaphragm muscle, me-sured as the magnitude of depolarization responses to repetitive, iontophoretic pulses of acetylcholine (ACh) onto neuromuscular endplates, is increased by addition of ATP to the perfusion medium. Depolarization responses begin to increase within the first min after addition of 10 mM ATP and plateau at 60% above control levels (mean value) after 4 to 6 min. Neither the magnitude nor the time course of the potentiations corresponds to changes in resting potential or membrane resistance. Other nucleotides are equally or less effective at the same concentration: ATP=ADP greater than UTP greater than AMP=GTP (=no added nucleotide control) The duration of the individual ACh responses does not increase during continuous exposure to the active nucleotides for up to 15 min except when the muscle is pretreated with eserine. Mild enzymatic predigestion of the muscle with collagenase and then protease, increasing the availability of the postjunctional membrane to bath-applied drugs, decreases the variability and increases the magnitude of the potentiation to a given dose of ATP. The dose-response curve for ATP is then more than half-maximal at 1 mM and the ranking of the other nucleotides relative to ATP is the same as without predigestion. There is an optimum Ca++ concentration for the potentiation between zero and 2 mM: potentiation is enhanced in Ca++ -free medium, partially blocked in twice-normal Ca++ medium, and totally blocked in Ca++ -free medium 10 min after a 5 min exposure to 2.5 mM EGTA. The similar Ca++ dependence of ACh receptor activation in the absence of added nucleotide suggests that ATP directly facilitates receptor activation by ACh. This facilitory action could be one of the physiological roles for the ATP released from stimulated phrenic nerve.