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Biomedical subjects

M Sullivan

Publications and source records attributed to M Sullivan.

At least 415 records · Page 23Linked to original sources
PubMed1978

The peptide chain elongation factor genes tufA and fus of Escherichia coli are intimately related physically.

Recent work from several laboratories has established the following points about the synthesis of the polypeptide chain elongation factors Tu and G in Escherichia coli. (i) Elongation factor Tu is the product of duplicate, highly conserved genes, tufA and tufB, which are widely separate parts of the chromosome. (ii) The molar concentration of this factor is considerably higher than that of elongation factor G which is encoded by the fus gene. (iii) Although the tufA and fus genes are close together and can be co-transcribed in the direction from fus to tufA, the tufA gene product is synthesized at several times the rate of the fus gene product. In an attempt to understand what mechanism(s) could account for the differential expression of the tufA and fus genes, we sought to obtain more precise information on the physical relationship of these genes. By examining heteroduplexes between restriction endonuclease-generated fragments of DNA containing the tufA, fus, and tufB genes, we have demonstrated that the fus and tufA genes are intimately related physically in one of two possible arrangements. Either the NH2-terminal region of the tufA gene is contiguous with the COOH-terminal region of the fus gene or the beginning of the tufA gene overlaps part of the fus gene. These results mean that if the tufA gene is always co-transcribed with the fus gene, then some mechanism must allow the tufA portion of the transcript to be translated more often than the fus gene portion of the transcript.

DNA, Bacterial↗
PubMed1978

Extravesical ureteral ectopia.

A case of an extravesically ectopic single ureter draining into the seminal vesicle is presented. Age of diagnosis, embryology of ureteral ectopia, and locations of the ureteral orifice are discussed. Suggestions are made for the diagnosis and treatment of ureteral ectopia.

Adolescent↗
PubMed1978

Adrenal cortical carcinoma.

A review of 28 cases of adrenal cortical carcinoma provides some insights into the natural history of this disease and suggests modifications in current techniques of diagnosis and management. Our patients ranged in age from 1 to 69 years but it is notable that all of our male patients were more than 39 years old. In addition the men tended to have high stage tumors that were nonfunctional. Female patients, on the other hand, were more evenly distributed in terms of stage, function and age at diagnosis. Staging was extremely important and is discussed in some detail. A dismayingly large number of patients were found to have stage 3 or 4 tumor at initial diagnosis, suggesting that aggressive and rapid evaluation and a high index of suspicion are important to optimize survival. Function is helpful but non-function is common and should not dissuade one from the diagnosis. Excretory urography with tomography followed by angiography frequently will provide the diagnosis. Endocrinologic evaluation should be done with alacrity. Survival with high stages of disease is poor and lengthy evaluation should not be allowed to delay prompt and, hopefully, curative surgery. Surgical resection is the key to cure; chemotherapy and radiotherapy provided relatively poor results in our hands although mitotane has shown a 34 to 54 per cent response rate.

Adolescent↗
PubMed1978

Comparison of cloned mouse alpha- and beta-globin genes: conservation of intervening sequence locations and extragenic homology.

We have cloned and characterized a 9.7-kilobase EcoRI fragment of mouse DNA that contains an alpha-globin gene. The gene is encoded in at least three discontinous segments of DNA interrupted by two small intervening sequences that can be visualized as R-loop structures in the electron miscroscope. The size of the gene and its small intervening sequences fits well with the known size of the alpha-globin mRNA precursor, suggesting that these intervening sequences, like those of beta-globin, are transcribed. Partial sequence analysis indicates that the larger intervening sequence interrupts the alpha-globin gene at a site exactly corresponding to that interrupted by the larger intervening sequences in both the beta-globin major and minor genes. This observation suggests that these sequences were present when the alpha- and beta-globin genes diverged in early vertebrate evolution, more than 500 million years ago. Furthermore, though alpha and betamaj genes are encoded on different chromosomes, when their sequences are compared directly by visualization of heteroduplex structures, only one 150- to 200-base-pair segment of homology is recognized. These homologous sequences are located on the 3'-flanking segments of both genes, about 1.5 kilobases from each.

Animals↗
PubMed1978

Intervening sequence of DNA identified in the structural portion of a mouse beta-globin gene.

The unusual electron microscopic appearance of a hybrid formed between 9S mouse beta-globin mRNA and its corresponding cloned gene segment is caused by at least one, and possibly two, intervening sequences of DNA that interrupt the mouse beta-globin gene. Such an interpretation is consistent with a paradoxical restriction site pattern previously noted in this gene and with the nucleotide sequence of that portion of the gene that spans both structural and intervening sequences. The large intervening sequence, approximately 550 base pairs in length, occurs in the structural globin sequence and immediately follows the beta-globin codon corresponding to amino acid 104. A smaller, putative intervening sequence is located close to the 5' end of the beta-globin-coding sequence but may reside beyond its initiation codon. The beta-globin gene thus appears to be encoded in two, and possibly three, discontinuous segments.

Animals↗
PubMed1978

Penetration into bone and tissues of clindamycin phosphate.

Clindamycin phosphate is an antibiotic which is effective against both Staphylococcus aureus and the anaerobic organisms. In thirteen patients, its concentration following joint replacement was measured by the agar diffusion method. In bone, the concentration was (mean +/- s.e. mean) 5.01 microgram/ml +/- 1.16, N=10; in capsule, 3.29 microgram/ml +/- 0.71, N=12; measured between 1.75 and 3.75 hr after intramuscular and intravenous injections, and in drainage fluid it amounted to 4.61 microgram/ml +/- 0.38, N=11 in 48 hr. Two patients developed diarrhoea which settled within a short period.

Aged↗
PubMed1977

Angiographic infarction of a large hypernephroma with a tissue adhesive for control of hematuria.

A case of a large inoperable hypernephroma in a 69-year-old man is presented. Recurrent life-threatening hematuria was controlled successfully by transcatheter embolization and infarction of the tumor using a tissue adhesive called isobutyl 2-cyanoacrylate. The patient remained without hematuria for 18 months until death from extensive metastatic diseases. The advantages and disadvantages of tissue adhesive as an embolization material are discussed.

Adenocarcinoma↗
PubMed1977

Anisometropic amblyopia and its treatment.

Full optical correction and closely supervised occlusion were effective in producing substantial visual improvement in 15 of 17 patients with anisometropic amblyopia. The age of patients varied from 2 to 12 years and all were followed for at least one year.

Amblyopia↗
PubMed1977

Diurnal variation in urinary oxalate.

The diurnal variation in urinary oxalate concentration and output was measured in 10 catheterised males. There was an increase in urinary oxalate concentration and output during the day and evening and an early morning decrease. It is thought that the daytime increase is related to dietary oxalate. These data suggest an elevated urinary oxalate excretion is more likely to occur during the day and a 24-hour urine collection may mask this effect.

Calcium↗
PubMed1976

Endotracheal tube as a factor in measurement of respiratory mechanics.

The measurement of respiratory mechanics is frequently performed on intubated patients. This study shows the effect which the turbulent and inertial characteristics of an endotracheal tube have on the accuracy of the measurement. Two techniques are examined utilizing a mechanical model: the least-squares and the phasor technique. It is concluded that both techniques will give erroneous results if the characteristics of the tube are not accounted for. The error is markedly reduced if the turbulent and inertial terms are accounted for in the analysis.

Air Movements↗
PubMed1976

Dietary interviewing by computer. An experimental approach to counseling.

A computer-based dietary counseling system was tested by sixty-four volunteers from the Boston area. Most of the patients seemed to benefit from their interaction with the computer, and the two participating nutritionists frequently found that the program was useful as an antecedent to their own one-to-one sessions with the patients.

Adult↗