Growth of endothelial and HeLa cells on a new multipurpose microcarrier that is positive,negative or collagen coated

A new cell culture microcarrier that can be covalently bonded by cell attachment proteins and can be thin-sectioned for electron microscopy was synthesized. It was easily made by sulfonating cross-linked polystyrene beads for a negative surface charge followed by covalent attachment of polyethylenimine for a positive charge. Cell attachment proteins, e.g. collagen, was covalently bonded directly to the microcarrier using a carbodiimide or after activating the microcarrier surface with glutaraldehyde. HeLa-S3 cells attached, spread and grew to confluence more efficiently on the positive microcarriers and those coated with collagen than on the negative ones. Endothelial cells grew best on those with a negative surface charge. The nature of the microcarrier surface was not the only aspect involved in cell adhesion but also the type of serum proteins adsorbed. Qualitatively different proteins coated the microcarriers depending upon whether the carrier was negative, positive or coated with collagen. Comparison of various types of available microcarriers indicated that the modified cross-linked polystyrene beads used here were best for transmission and scanning electron microscopy. Endothelial cells grown on the microcarriers had the same ultrastructure as cells grown in monolayers in culture dishes. Of a variety of microcarriers tested the modified cross-linked polystyrene beads were the only ones that could be used for both ultrastructural and biochemical techniques.     

Genetic polymorphism of serum complement components in the chimpanzee

Significant polymorphism of serum complement components Bf, C2, C3, C6, and C8 in the chimpanzee has been demonstrated. The data are consistent with the hypothesis thatC2 andBf are closely linked toChLA and argue against close linkage ofChLA toC3 or toC8, as in man. In addition, a blank allele for C6 and C6 deficiency was detected in several chimps.     

Origin of the left anterior descending coronary artery from the pulmonary artery: An unusual cause of angina in a middle-aged woman

A 48-year-old woman was admitted to our institution with angina pectoris and a systolic murmur. At cardiac catheterization, she was found to have an anomalous origin of the left anterior descending coronary artery from the pulmonary trunk. There was also an associated atrial septal defect and a bicuspid aortic valve.     

Traumatic disruption of the fibrous skeleton of the heart, with injury of the tricuspid and mitral valves, aortic annulus, and ventricular septum

In an automobile accident, a young man sustained blunt trauma to the chest that caused injury to the fibrous skeleton of the heart. The mitral and tricuspid valves and their annuli were lacerated, the aortic annulus was separated from the ventricular septum, and the ventricular septum was disrupted; however, with surgical management, the patient survived.     

Thermal biology of the common garter snake Thamnophis sirtalis (L.)

Summary The thermoregulatory significance of a striped-melanic colour polymorphism in the common garter snake, Thamnophis sirtalis, was assessed through a combination of labortory experimentation and field study. In experiments with living snakes the melanic morph maintained a higher body temperature than the striped morph, when exposed to natural insolation. Experiments with excised skin showed that this thermal advantage is attributable to some integumental difference between the two morphs. Body temperatures of snakes in the field revealed that, during the colder part of the active season, melanics were able to stay warmer than striped snakes by an amount (1.24 C°) approximating the difference observed in the laboratory. Some evidence and argument is presented to suggest that melanism also may confer protection against overheating in warm periods.     

Multiple ribosomal RNA cleavage pathways in mammalian cells

The sequence content of mouse L cell pre-rRNA was examined by RNA gel transfer and blot hybridization. Nuclear RNAs were separated by agarose gel electrophoresis, transferred to diazo-paper, and hybridized to twelve different restriction fragments that are complementary to various sections of 45S pre-rRNA. An abundant new 34S pre-rRNA and less abundant new 37S, 26S and 17S pre-rRNAs were detected. The presence of these new pre-rRNAs suggests the existence of at least two new pre-rRNA cleavage pathways. 34S and 26S pre-rRNAs were also detected in HeLa cells suggesting that these new cleavage pathways are characteristic of mammalian cells. Further, an abundant new 12S precursor to 5.8S rRNA was also detected and is common to all the proposed cleavage pathways. The previously identified 45S, 41S, 32S and 20S pre-rRNAs were readily detected and their general structure confirmed. The 20S pre-rRNA is characteristic of the known pathway used by HeLa and other cells, and its presence suggests that growing mouse L cells use this pre-rRNA cleavage pathway. The 36S pre-rRNA characteristic of the previously described mouse L cell cleavage pathway was not detected. In all these cleavage pathways pre-rRNA cleavage sites are apparently identical and occur at or near the termini of the mature 18S, 5.8S and 28S rRNA sequences. The pathways differ only in the temporal order of cleavage at these sites.     

An estrogen receptor from xenopus laevis liver possibly connected with vitellogenin synthesis

This paper describes an estrogen receptor which is found in both the nucleus and cytoplasm of liver cells from male Xenopus laevis, and which seems to be involved in the induction of vitellogenin synthesis. It has a high affinity for estradiol (K_d = 0.5 × 10^?9 M), and the affinities of various steroids for the receptor correlate well with their ability to induce vitellogenin synthesis. It sediments at 3.5S at 0°C in 0.5 M KCI. The rate of sedimentation is unaffected by incubation at 20°C prior to centrifugation, but increases if the salt concentration is lowered to 0.1 M KCI or to zero. It has a Stokes radius of 2.6 nm and a molecular weight of approximately 40, 000. The receptor is present at very low levels compared to other steroid target tissues (50–100 fold less than chick oviduct). The cytoplasm of a single hepatocyte contains 92 ± 18 binding sites for estradiol, while each nucleus contains 99 ± 19 sites.