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Biomedical subjects

R J Rothstein

Publications and source records attributed to R J Rothstein.

At least 37 records · Page 2Linked to original sources
PubMed1982

Futility of skull radiography for nontraumatic conditions.

Indications for post-traumatic skull radiographs have been well publicized, and "high-yield" criteria have been established. Such criteria have not been established for patients without trauma. We report a review of 157 consecutive skull series taken for nontraumatic conditions. Skull radiography was found to be extremely "low yield" in the evaluation of the nontraumatized patient--only 4.5% of the films showed significant abnormalities related to the patient's diagnosis. Moreover, regardless of radiographic results, skull films had little impact on further diagnostic workup or on patient management. Our results suggest that more stringent criteria should be considered in ordering skull radiographs for nontraumatic indications.

Evaluation Studies as Topic↗
PubMed1981

Cardiac conduction and rhythm disturbances following suicidal ingestion of mesoridazine.

The phenothiazine derivatives, particularly chlorpromazine and thioridazine, are known to produce significant electrocardiographic abnormalities. Until now, documented life-threatening arrhythmias have not been reported following large doses of mesoridazine, the besylate salt of a metabolite of thioridazine and a relatively recent addition to the phenothiazine group. We describe such a case in which alterations in both impulse conduction (first-degree atrioventricular block, prolonged QRS duration, and right axis deviation) and impulse formation (supraventricular and ventricular tachycardia) were noted following a suicidal ingestion of mesoridazine. The electrophysiologic mechanisms underlying phenothiazine-induced arrhythmogenesis are reviewed.

Adult↗
PubMed1981

Colchicine overdose: report of two cases and review of the literature.

Colchicine overdose is an uncommon but serious problem that may be missed or ignored unless the physician is aware of the significant potential for, and the various stages of, toxicity. We report two fatal cases in which the potential for lethal complications was not initially realized. Both patients developed multiple organ damage characteristic of severe colchicine toxicity. Awareness and appropriate initial therapy are important if death is to be prevented in colchicine overdose.

Adolescent↗
PubMed1981

Yeast transformation: a model system for the study of recombination.

DNA molecules that integrate into yeast chromosomes during yeast transformation do so by homologous recombination. We have studied the way in which circular and linear molecules recombine with homologous chromosomal sequences. We show that DNA ends are highly recombinogenic and interact directly with homologous sequences. Circular hybrid plasmids can integrate by a single reciprocal crossover, but only at a low frequency. Restriction enzyme digestion within a region homologous to yeast chromosomal DNA greatly enhances the efficiency of integration. Furthermore, if two restriction cuts are made within the same homologous sequence, thereby removing an internal segment of DNA, the resulting deleted-linear molecules are still able to transform at a high frequency. Surprisingly, the integration of these gapped-linear molecules results in replacement of the missing segment using chromosomal information. The final structure is identical to that obtained from integration of a circular molecule. The integration of linear and gapped-linear molecules, but not of circular molecules, is blocked by the rad52-1 mutation. Consideration of models for plasmid integration and gene conversion suggests that RAD52 may be involved in the DNA repair synthesis required for these processes. Implications of this work for the isolation of integrative transformants, fine-structure mapping, and the cloning of mutations are discussed.

Base Composition↗
PubMed1980

Intravenous theophylline therapy in asthma: a clinical update.

Theophylline preparations have long been the mainstay in the management of asthma. Recently clinical and laboratory investigations have provided us with some useful information regarding the appropriate dosage and elimination of the drug. If morbidity is to be avoided, knowledge of the basic pharmacokinetics of theophylline, as well as recognition of the parameters which have clinically significant influences on those kinetics, is essential to the emergency physician who has occasion to treat asthmatics. Theophylline levels should be utilized whenever available, but clinical acumen must suffice in their absence. Subtle signs of toxicity must be recognized before more serious complications ensue. Armed with more recent knowledge, the emergency physician should be able to provide optimal therapy for the asthmatic.

Adenosine Monophosphate↗
PubMed1980

Genes affecting the expression of cytochrome c in yeast: genetic mapping and genetic interactions.

The four mutant genes, cyc2, cyc3, cyc8 and cyc9, that affect the levels of the two iso-cytochromes c in the yeast Saccharomyces cerevisiae have been characterized and mapped. Both cyc2 and cyc3 lower the amount of iso-1-cytochrome c and iso-2-cytochrome c; whereas, cyc8 and cyc9 increase the amount of iso-2-cytochrome c. The cyc2, cyc3, cyc8 and cyc9 genes are located, respectively, on chromosomes XV, I, II and III, and are, therefore, unlinked to each other and unlinked to CYC1, the structural gene of iso-1-cytochrome c and to CYC7, the structural gene of iso-2-cytochrome c. While some cyc3 mutants are completely or almost completely deficient in cyotchromes c, none of the cyc2 mutants contained less than 10% of parental level of cytochrome c even though over one-half of the mutants contain UAA or UAG nonsense mutations. Thus, it appears as if a complete block of the cyc2 gene product still allows the formation of a residual fraction of cytochrome c. The cyc2 and cyc3 mutant genes cause deficiencies even in the presence of CYC7, cyc8 and cyc9, which normally cause overproduction of iso-2-cytochrome c. We suggest that cyc2 and cyc3 may be involved with the regulation or maturation of the iso-cytochromes c. In addition to having high levels of iso-2-cytochromes c, the cyc8 and cyc9 mutants are associated with flocculent cells and other abnormal phenotypes. The cyc9 mutant was shown to be allelic with the tup1 mutant and to share its properties, which include the ability to utilize exogenous dTMP, a characteristic flocculent morphology, the lack of sporulation of homozygous diploids and low frequency of mating and abnormally shaped cells of alpha strains. The diverse abnormalities suggest that cyc8 and cyc9 are not simple regulatory mutants controlling iso-2-cytochrome c.

Chromosome Mapping↗
PubMed1980

Dependence on mating type for the overproduction of iso-2-cytochrome c in the yeast mutant CYC7-H2.

The CYC7-H2 mutation causes an approximately 20-fold overproduction of iso-2-cytochrome c in a and alpha haploid strains of the yeast Saccharomyces cerevisiae due to an alteration in the nontranslated regulatory region that is presumably contiguous with the structural region. In this investigation, we demonstrated that heterozygosity at the mating type locus, a/alpha or a/a/alpha/alpha, prevents expression of the overproduction, while homozygosity, a/a and alpha/alpha, and hemizygosity, a/0 and alpha/0, allow full expression of the CYC7-H2 mutation, equivalent to the expression observed in a and alpha haploid strains. There is no decrease in the overproduction of iso-2-cytochrome c in a/alpha diploid strains containing either of the other two similar mutations, CYC7-H1 and CYC7-H3. It appears as if active expression of one or another of the mating-type alleles is required for the overproduction of iso-2-cytochrome c in CYC7-H2 mutants.

Base Sequence↗
PubMed1979

Emergency management of poisoning and overdose.

The management of the poisoned patient can be difficult and challenging. The task often demands the physician's entire resources in putting together pieces of history and significant physical findings to make a diagnosis. He must then carefully support and stabilize the patient under constant monitoring, while making efforts to prevent further absorption of the toxin, enhance excretion, and treat complications as they arise.

Adult↗
PubMed1978

Syphilis and pelvic inflammatory disease.

Since screening every patient in the emergency department for venereal disease is impractical, we hypothesized that patients with the clinical diagnosis of pelvic inflammatory disease (PID) might be at higher risk and a group that should be screened. Seventy women with a clinical diagnosis of PID treated in our adult emergency department from July to November 1976 were screened for syphilis using three separate serologic tests: Venereal Disease Research Laboratory, fluorescent treponemal antibody absorption, and treponema pallidum hemagglutination. The incidence of positive serologies in our study group was significantly higher (11.4%) than that of 100 controls (4%). All patients with a clinical diagnosis of PID should be screened for syphilis using both FTA-Abs and TPHA tests, as well as a VDRL.

Adult↗
PubMed1977

The effect of ochre suppression on meiosis and ascospore formation in Saccharomyces.

The effect of altered tyrosyl-tRNAs on the developmental process of sporulation was examined. Mutations in eight independent loci resulting in tyrosine-inserting nonsense suppressor were tested for their effects on sporulation. Different levels of inhibition were found ranging from SUP3-omicron, which caused the greatest reduction of sporulation (7-17% of wild type), to SUP11-omicron which caused no reduction in sporulation. Since the SUP3-omicron mutation exhibited the greatest effect, it was studied in detail. Although SUP3-omicron is a dominant nonsense suppressor, its effect on sporulation is recessive. Expression of the sporulation deficiency is dependent upon the stage of transfer from glucose growth medium (i.e., log, early stationary, etc.) to sporulation medium. SUP3-omicron/SUP3-omicron diploid cells transferred from log or early stationary phase are capable of sporulation, whereas cells transferred after early stationary phase (i.e., after adaptation to respiration) exhibit poor sporulative ability. Sporulation events were examined under restrictive conditions to observe those events completed by SUP3-omicron/SUP3-omicron diploids. The early events of sporulation occur in these cells. Later events are completed by progressively fewer cells. Premeiotic DNA synthesis occurred in approximately 40% of the cells, nuclear segregation occurred in 20%, and finally, only 2% formed asci. The fact that fewer late-sporulation events occur under restrictive conditions can be explained by increased efficiency of suppression.

Meiosis↗
PubMed1977

A genetic fine structure analysis of the suppressor 3 locus in Saccharomyces.

A meiotic fine structure map of a yeast tyrosine-inserting ochre suppressor, SUP3-omicron, was constructed. This was accomplished by examining ten intragenic suppressor-inactive revertants for their relationship to each other and to the original SUP3-omicron mutation. The second-site revertants map on both sides of the SUP3-omicron mutation. The meiotic map length based on the summation of short intervals is 45+/10(5) asci.

Chromosome Mapping↗