Dominant optic atrophy, deafness, ptosis, ophthalmoplegia, dystaxia, and myopathy. A new syndrome

Twenty-three members of a 96-member family exhibited an autosomal dominant disorder which has not previously been described. This disorder involves progressive optic atrophy, abnormal electroretinography without retinal pigment changes, and progressive sensorineural hearing loss usually evident in the first or second decade of life. In midlife, ptosis, ophthalmoplegia, dystaxia, and a nonspecific myopathy occur.

Parietal foramina clavicular hypoplasia. An autosomal dominant syndrome

A male infant was evaluated with macrocephaly, scaphocephaly , a high forehead, a parietal foramen, a midline posterior occipital dermoid, and sloped shoulders. A skeletal survey also showed distal hypoplasia of the clavicles with bilateral loss of the acromion. Similar features were evident in his father, grandfather, and two paternal great-aunts. To our knowledge, this is the second report of this syndrome, which may be designated as parietal foramina-cleidocranial dysplasia. Our three-generation family and male-to-male transmission clearly established an autosomal dominant mode of inheritance for this syndrome.

Isolation and sequencing of a cDNA clone for a human HLA-ABC antigen

A cDNA clone, pHLA-A, containing sequences specific for a human class I HLA antigen heavy chain, was isolated from a bank of clones made from partially purified HLA-ABC heavy chain mRNA from the human lymphoblastoid cell line Bristol 8 (HLA-A1, A2, B8, B16). The clone corresponded to sequence for the -COOH-terminal 117 amino acids of an HLA-ABC alpha-chain. It differed in at least 15 positions from the published HLA-B7 amino acid sequence but in only two residues when compared to the partial HLA-A2 protein sequence, and was identical to the HLA-A3 protein sequence derived from the nucleotide sequence of the gene. It also differed from some published human HLA-ABC sequences by the addition of three extra -COOH-terminal amino acids: cysteine-lysine-valine. The clone may correspond to either the HLA-A1 allele, for which independent sequence information is not available, or to HLA-A2, in which case there are possible explanations for the discrepancies. Comparison of the pHLA-A sequence with genomic HLA sequences suggests variations in splicing at the end of the protein coding region in some HLA-ABC heavy chain genes, and the use of alternative poly(A) addition sites.

Failure of translational repression in the phage f2 op3 mutant is not due to an altered coat protein-RNA interaction

A secondary phenotype of the op3 mutant of RNA bacteriophage f2 is the absence of translational repression of the phage replicase gene by the phage coat protein. We have synthesized RNA fragments corresponding to the site of translational repression for both the wild type and the op3 mutant. Using a quantitative assay, we show that the affinity of the closely related R17 coat protein for the mutant and wild type RNA fragments is the same. In addition, we find that the op3 and R17 coat proteins bind to the wild type RNA fragment with essentially identical dissociation constants. Thus, the altered regulation of replicase protein synthesis in the op3 mutant does not appear to be due simply to a reduced affinity of the translational repressor for its target site.

Interaction of R17 coat protein with its RNA binding site for translational repression

The interaction between bacteriophage R17 coat protein and its RNA binding site for translational repression was studied as an example of a sequence-specific RNA-protein interaction. A nitrocellulose filter retention assay is used to demonstrate equimolar binding between the coat protein and a synthetic 21 nucleotide RNA fragment. The Kd at 2 degrees C in a buffer containing 0.19 M salt is about 1 nM. The relatively weak ionic strength dependence of Ka and a delta H = -19 kcal/mole indicates that most of the binding free energy is due to non-electrostatic interactions. Since a variety of RNAs failed to compete with the 21 nucleotide fragment for coat protein binding, the interaction appears highly sequence specific. We have synthesized more than 30 different variants of the binding site sequence in order to identify the portions of the RNA molecule which are important for protein binding. Out of the five single stranded residues examined, four were essential for protein binding whereas the fifth could be replaced by any nucleotide. One variant was found to bind better than the wild type sequence. Substitution of nucleotides which disrupted the secondary structure of the binding fragment resulted in very poor binding to the protein. These data indicated that there are several points of contact between the RNA and the protein and the correct hairpin secondary structure of the RNA is essential for protein binding.

Interaction of R17 coat protein with synthetic variants of its ribonucleic acid binding site

The specificity of the interaction between R17 coat protein and its site of translational repression on R17 RNA was studied by enzymatically synthesizing 23 sequence variants of the RNA binding site and measuring their affinity to the coat protein by a nitrocellulose filter binding assay. Experiments using oligomers truncated on the 3' and 5' termini allowed precise determination of the edges of the binding domain. Several oligomers which disrupted one or more of the base pairs in the binding site failed to bind coat protein, establishing the importance of RNA secondary structure for the interaction. Substitution at two single-stranded positions with each of the common bases affected Ka very differently. In one case, Ka was reduced substantially no matter which base was substituted for an adenine. At the other position, when a uracil was substituted with a purine, Ka decreased 10-100-fold, whereas when it was substituted by a cytosine, Ka increased about 5-fold. These studies indicate that the protein and the RNA hairpin loop interact over an extensive area and that several different types of contacts form to stabilize the complex.

Sequence-specific interaction of R17 coat protein with its ribonucleic acid binding site

The interaction between phage R17 coat protein and its RNA binding site for translational repression was studied as an example of a sequence-specific RNA--protein interaction. Nuclease protection and selection experiments define the binding site to about 20 contiguous nucleotides which form a hairpin. A nitrocellulose filter retention assay is used to show that the binding between the coat protein and a synthetic 21-nucleotide RNA fragment conforms to a simple bimolecular reaction. Unit stoichiometry and a Kd of about 1 nM are obtained at 2 degrees C in buffer containing 0.19 M salt. The interaction is highly sequence specific since a variety of RNAs failed to compete with the 21-nucleotide fragment for coat protein binding.

Kinetic and thermodynamic characterization of the R17 coat protein-ribonucleic acid interaction

A filter retention assay is used to examine the kinetic and equilibrium properties of the interaction between phage R17 coat protein and its 21-nucleotide RNA binding site. The kinetics of the reaction are consistent with the equilibrium association constant and indicate a diffusion-controlled reaction. The temperature dependence of Ka gives delta H = -19 kcal/mol. This large favorable delta H is partially offset by a delta S = -30 cal mol-1 deg-1 to give a delta G = -11 kcal/mol at 2 degrees C in 0.19 M salt. The binding reaction has a pH optimum centered around pH 8.5, but pH has no effect on delta H. While the interaction is insensitive to the type of monovalent cation, the affinity decreases with the lyotropic series among monovalent anions. The ionic strength dependence of Ka reveals that ionic contacts contribute to the interaction. Most of the binding free energy, however, is a result of nonelectrostatic interactions.

Sequences related to HLA-DR alpha chain on human chromosome 6: restriction enzyme polymorphism detected with DC alpha chain probes

Three sets of cosmid clones--containing the HLA-DR alpha chain gene and two additional related genes--were isolated from human genomic DNA libraries by using a cDNA probe for the HLA-DR alpha chain. Southern blot analysis using DNA from somatic cell hybrids indicated that all of the clones mapped to chromosome 6. Partial sequence analysis showed that the two additional related genes were highly homologous to each other, and to the HLA-DR alpha chain, in parts of the exon that encoded the alpha 2 domain but were more divergent in intron sequences. One of the genes corresponds to the HLA-DR-related DC series. DNA probes made from this gene revealed marked restriction enzyme polymorphism when hybridized to genomic DNA from HLA-DR typed homozygous cell lines. The patterns obtained from a number of homozygous and heterozygous cell lines correlated with the HLA-DR crossreactive serotypes and also indicated that there is a further sequence in the haploid human genome that is closely homologous with the DC alpha chain sequence. One family was studied and showed the expected HLA-DR-associated inheritance of restriction enzyme patterns. No polymorphism has yet been demonstrated in restriction enzyme fragments that include the other cloned sequence, which may correspond to the SB alpha chain gene or to a novel HLA-DR-related gene. These experiments indicate that there are at least three sequences in the human genome related, but not identical, to the HLA-DR alpha chain gene.

The effect of dialysate sodium concentration on body fluid compartment volume, plasma renin activity and plasma aldosterone concentration in chronic hemodialysis patients

Six stable chronic hemodialysis patients received six hemodialysis treatments: two each with the dialysate sodium concentration (DNa) 7% greater than serum sodium concentration, two with a DNa equal to serum sodium concentration and two with the DNa 7% less than the serum sodium concentration. During one treatment with each dialysate 2 kg of fluid was removed and during the other treatments the patient's weight was kept constant. Total body water (TBW), intracellular water (ICW), extracellular water (ECW), plasma volume (PV), plasma renin activity (PRA), aldosterone (ALDO), Na, BUN and osmolality were determined before and after each treatment. Fluid removal during dialysis had no effect on ICW with essentially all the fluid removed during dialysis coming from ECW. ICW increased with low DNa and decreased with high DNa. The effect of DNa on ECW and PV was the opposite of that on ICW. PRA increased and ALDO decreased during dialysis. Predialysis ALDO directly correlated with PRA (r = 0.68, p less than 0.001) but not with serum potassium concentration. Post dialysis ALDO was not significantly correlated with either PRA or potassium. Fluid removal and low DNa increased both PRA and ALDO. These studies indicate that water shifts from the extracellular space into intracellular space when DNa is lower than serum Na and the reverse is true when DNa exceeds serum Na. Plasma aldosterone decreases during dialysis despite an increase in PRA, possibly related to the decrease in serum potassium concentration. The effect of fluid removal and low DNa on PRA and ALDO may be related to a reduction in ECW and/or PV.

First-trimester prenatal counseling in private practice

The future of first-trimester prenatal counseling in private practice is as bright as office nurses choose to make it. Currently, counseling of this kind is being offered only at two places, the Sunnyside office and at the office of another obstetrician whose nurse was trained for counseling by the author. A huge network of private practice counseling is possible, however, if office nurses would learn these skills. Despite some reports of opposition, many physicians would welcome nurses in this counselor's role. A 1972 survey of obstetrician-gynecologists showed that 51% favored delegating more tasks to the office nurse, if only to free the physicians's time to see additional patients. According to the physicians surveyed, the "maternity nurse could perform many of the prevention and counseling routines" the physicians felt took up roughly 75% of their office time. First-trimester prenatal counseling in private practice is not only possible in a structured, group-oriented sense, but it is necessary and worthwhile as well. Patients have become increasingly aware of their rights as consumers of health care. Where they get their information-and how accurate and complete it is-is largely up to the nursing profession.

A general model for preventive intervention in clinical practice

A five-stage collaborative project to develop curriculum and associated instructional materials in preventive medicine has been initiated by the Association of Teachers of Preventive Medicine in cooperation with the Center for Educational Development in Health at Boston University. As part of the first stage, a general model delineating physician responsibilities in the preventive dimension of clinical practice was developed and analyzed in terms of requisite attitudes, knowledge, and skills. The model is based on a theoretical matrix modified by consideration of optimal physician performance in three tracer conditions (lung cancer, gonorrhea, and hypertension) and the results of a Delphi survey among a sample of 50 primary care practitioners. Competency in planning a practice-based program of prevention and the ability to assist patients in modifying patterns of behavior emerged as significant determinants of physician effectiveness in preventive intervention.

Growth of liver accompanied by an increased binding of aminoacyl-transfer ribonucleic acids

Homogenates of rat liver obtained 3 or 14 days after partial hepatectomy were used to prepare the postmicrosomal pH5-supernatant fraction and to prepare salt-wash fractions of the 40S ribosomal subunits and the 80S ribosomes. The factor-dependent binding of methionyl-tRNAfMet to ribosomes and the elongation-factor-1-dependent binding of phenylalanyl-tRNA to ribosomes were both increased after 3 days of growth, but not after 14 days of growth. An activity inhibitory to phenylalanyl-tRNA binding that was located in ribosomal wash fractions was decreased after 14 days of growth. Since the decreased inhibitory activity was obtained from the ribosomes and was tested against ribosomes and excess of pH5-supernatant fraction from control rat liver, its action was separate from the phenylalanyl-tRNA binding activities of the pH5-supernatant fractions from sham-operated and regenerating liver.