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Biomedical subjects

M Fried

Publications and source records attributed to M Fried.

At least 361 records · Page 20Linked to original sources
PubMed1982

Excessive hypermetropia: review and case report documented by echography.

The case of an 11-year-old boy with hypermetropia of +22.0 diopters is reported. Axial length was only 14.8 mm. The features and extreme rarity of this variation in the shape of the globe is outlined. The dimensions of the eyeball were measured by echography and compared to the emmetropic eye of the adult. Only vitreous length was found to be shortened, while the dimensions of the anterior segment were within normal limits. The term posterior microphthalmos without microcornea was chosen. Associated pseudopapilledema and choroidal folds were found. The literature is reviewed.

Biometry↗
PubMed1981

Equilibria and kinetics of lac repressor-operator interactions by polyacrylamide gel electrophoresis.

We describe the use of gel electrophoresis in studies of equilibrium binding, site distribution, and kinetics of protein-DNA interactions. The method, which we call protein distribution analysis, is simple, sensitive and yields thermodynamically rigorous results. It is particularly well suited to studies of simultaneous binding of several proteins to a single nucleic acid. In studies of the lac repressor-operator interaction, we found that binding to the so-called third operator site (03) is 15-18 fold weaker than operator binding, and that the binding reactions with the first and third operators are uncoupled, implying that there is no communication between the sites. Pseudo-first order dissociation kinetics of the repressor-203 bp operator complex were found to be temperature sensitive, with delta E of 80 kcal mol-1 above 29 degrees C and 26 kcal mol-1 below. The half life of the complex (5 min at 21 degrees C) is shorter than that reported for very high molecular weight operator-containing DNAs, but longer than values reported for much shorter fragments. The binding of lac repressor core to DNA could not be detected by this technique: the maximum binding constant consistent with this finding is 10(5) M-1.

DNA Restriction Enzymes↗
PubMed1981

Detection in situ of foreign DNA in eukaryotic cells.

A simple technique is described that allows mixed populations of eukaryotic cells to be screened for clones containing multiple copies of a particular DNA. Essentially, eukaryotic cells are transferred to either nitrocellulose of Whatman 541 filters, and their DNA is immobilised in situ. Exposure of the filters to a 32P-labeled DNA "probe" results in detectable hybridisation only at the positions of clones containing multiple copies of the DNA. Using Whatman 541 paper, a portion of the cells, evenly distributed throughout the mixed population is retained on the culture dish, and can be propagated further for subsequent cell cloning. The technique has allowed rapid distinction of clones of transformed rat cells that contain a single or only a few copies per cell of polyoma viral DNA from clones maintaining multiple copies. The technique has also been used to distinguish between clones of mouse L-cells containing multiple and only a few copies of 0X174 DNA. In this manner the technique allows rapid detection of cells amplifying a particular species of DNA. Finally, the method can be used to detect cells assimilating many copies of a foreign DNA, even in the absence of a co-transfected selectable marker.

Animals↗
PubMed1981

Capsules, infection, and intraluminal antibiotics.

Staphylococcus epidermidis, a normal cutaneous inhabitant previously shown to be present in 67 percent of nipple secretions, has been cultured from 55 percent of surgical mammary pockets prior to implant insertion and from the interior of 71 percent of fibrous capsules explored at open capsulotomy. Cephalothin and gentamicin placed within the lumen of inflatable breast implants in vitro have been shown to diffuse outward through the silicone shell. The use of intraluminal cephalothin and gentamicin in vivo has significantly reduced our incidence of capsular contracture following both primary mammary augmentation and secondary open capsulotomy. The authors believe that the cause of fibrous capsular contracture may be a low-grade periprosthetic infection, and that the unique permeability characteristics of the silicone shell may permit sustained antimicrobial activity at the surface of the prosthesis.

Cephalothin↗
PubMed1981

Loss of functional large T-antigen and free viral genomes from cells transformed in vitro by polyoma virus after passage in vivo as tumor cells.

We have analyzed the state, arrangement, and expression of polyoma viral DNA sequences in a number of in vitro-transformed Fischer rat cells before and after growth in vivo as tumour cells. When the in vitro lines used to induce the tumors contained only a single insert of viral sequences and did not produce either a full-size 100,000-dalton (100K) large T-antigen or free viral genomes, no differences in the above-mentioned properties were observed. By contrast, in vitro cell lines containing multiple inserts of viral sequences, a functional 100K large T-antigen, and free viral genome induced tumor cells which displayed a reduced number of inserts of viral sequences and which did not produce either a functional 100K large T-antigen or free viral genomes. All of the in vitro lines and their tumor cell derivatives expressed the polyoma virus 55K middle and 22K small T-antigen species. Possible mechanisms for the selection in vivo against cells containing a functional 100K large T-antigen and consequently free viral genomes are discussed.

Animals↗
PubMed1980

[Incontinentia pigmenti (Block-Sulzberger syndrome) associated with congenital retinal fold--a long-term 18-year observation].

Report on a case of incontinentia pigmenti presenting with the main characteristics features: patchy hyperpigmentation of the skin, alopecia and dental anomalies. In addition to the rare hyperpigmentation of the lower eyelids, hemiatrophy of the right face and horizontal nystagmus were found. Eye involvement consisted of a congenital retinal fold with retinal vessels draen into and bordered by pigment clumps.--When the patient with 14 total retinal detachment associated with a totally liquefied vitreous occurred and surgical reattachment failed. As a rarity in this case, the full picture of retrolental fibroplasia was not present; it was possible to follow developments over a period of 18 years.

Alopecia↗
PubMed1980

Prophylaxis of retinal detachment.

Prophylactic treatment of retinal tears, holes, and degenerations has proved very effective in a convincing series of results. Ever since prophylactic treatment became available the number of patients treated prophylactically has been growing worldwide annually. While it will never be possible to prevent all retinal detachments, no significant fall in the rate of retinal detachment has been reported. Yet this is what we expect from prophylaxis. Most patients with manifest retinal detachment have not in fact received previous prophylactic treatment for various reasons. The ophthalmologist involved in prophylaxis is confronted with large numbers of patients. Preventive treatment has to be highly selective to be practicable and safe. Only lesions presenting a definite risk of retinal detachment should be treated. The criteria for treatment must be revised from time to time. Three types of failure should be noted: (a) Retinal detachment "because of" prophylaxis, (b) Retinal detachment "in spite of" prophylaxis, (c) Retinal detachment in cases in which prophylaxis was omitted because of a "false negative diagnosis". On the other hand overtreatment and misuse, i.e. prophylactic treatment of innocuous lesions, based on "false-positive diagnosis", apparently takes place without reducing the incidence of retinal detachment but resulting in expense and stress to the patient and in some cases even in complications of treatment. It seems unlikely that we have reached the final stage in the prevention of retinal detachment. Screening techniques, selection criteria, treatment, and follow-up should be improved. Until there are fewer detachments to operate upon, much remains to be done.

Humans↗
PubMed1979

Polymorphism in fowl serum albumin. VI. Changes in in vitro protein synthesizing activity in developing embryonic fowl liver.

Cell-free protein synthesizing systems were prepared from the livers of chick embryos at selected ages and the characteristics of individual fractions were compared. While polysomes showed decreasing size with older embryos, isolated polysomes did not differ significantly in amino acid incorporating activity when assayed with standard cell sap. When assayed with standard polysomes, cell sap activity decreased with increasing developmental age whether incorporation was measured using (3H)lysine, (3H)leucine, or [3H]aminoacyl-tRNA. Free amino acid concentrations in the cell sap showed reproducidble independent variation during development which was taken into consideration in calculating net amino acid incorporation. A larger increase in ribonuclease activity was observed during development; however, nuclease inhibitor activity was absent before day 15 but increased thereafter. Aminoacyl-tRNA sythetase activity did not vary significantly. It is proposed that the observed changes in the rate of cell-free protein synthesis result not only from increasing ribonuclease activity with increasing developmental age but also from changes in the activity of other soluble factors.

Amino Acids↗
PubMed1979

Report of a case resembling the 'fleck retina of Kandori' with ectodermal peculiarities and macula degeneration.

This report involves the case of a 36-year-old woman followed-up for nine years. The symptoms include unique, sharply-defined, irregular, yellow, large flecks of the retina combined with bilateral macula degeneration. The patient's rusty-red hair, enamel dysplasia, and ashen-gray skin color were also noted. It is argued that this case is very likely identical with the 'fleck retina of Kandori' and as such, the first case reported outside Japan. The literature is reviewed.

Adult↗
PubMed1979

Nucleotide sequence analysis of the leader segments in a cloned copy of adenovirus 2 fiber mRNA.

Fiber mRNA of adenovirus 2 has been used as a template for RNA-dependent DNA polymerase. The resulting cDNA/RNA hybrids have been inserted at the Pst I site of the plasmid vector pBR322 after A:T tailing. One recombinant plasmid, pJAW 43, has been characterized in detail and shown to contain sequences from the main body of fiber mRNA, the three leaders common to most late adenoviral mRNAs and a fourth leader found in some species of fiber mRNA. The complete DNA sequence of the leader region has been determined and does not contain the initiation codon AUG, although this codon does occur immediately downstream from the junction between the fourth leader and the main body of the fiber mRNA. The first leader (map coordinate 16.6) is 41 nucleotides long, the second (from 19.6) is 71 nucleotides, the third (from 26.6) is 88 nucleotides and the fourth (from 78.5) is 181 nucleotides. The location of junctions between viral leaders and intervening sequences has been determined by reference, where possible, to sequences of the adenovirus 2 genome. Although the presence of short repeated sequences at the boundaries of intervening sequences and leaders makes it impossible to locate the splice point unambiguously, all of the leader-intervening sequence junctions can be arranged to stress a common feature--the presence of the dinucleotides GT and AG at the 5' and 3' ends, respectively, of the intervening sequences. This prototype sequence, which has also been recognized at or near the splice points in other eucaryotic systems, is possibly part of a larger unit which serves as a recognition site for specific excision-ligation events that ultimately lead to the production of mature mRNAs.

Adenoviruses, Human↗