A cysteine-requiring mutant of the parent strain Escherichia coli Hfr Cavalli (RC(rel), Met(-), lambda) has been isolated. The mutant was selected by using replica plating after mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine. The mutation appears to be in the gene for sulfite reductase, since the mutant could utilize sulfide but not sulfite as a sulfur source. The mutant was found to be RC(rel) with respect to both methionine and cysteine. During cysteine starvation, transfer ribonucleic acid (tRNA) deficient in 4-thiouracil was produced, and in vivo studies indicate that this tRNA can accept sulfur groups to a greater extent than normal tRNA. Further, there were differences both in the rate and extent of amino acid acceptance between normal and sulfur-deficient tRNA. This suggests that thionucleotides are involved in at least one of the biological functions of the tRNA molecule.

Amino Acids↗

PubMed1967

An implantable telemeter for determining body temperature and heart rate.

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Animals↗

PubMed1960

The effect of sources of nonessential nitrogen on nitrogen balance in young adults.

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Adult↗

PubMedDate not supplied

Adult attention-deficit/hyperactivity disorder: neuropsychological correlates and clinical presentation.

We compared the neuropsychological test performance of adult ADHD patients to the neurocognitive profiles of control subjects recruited from the general population. We administered a neuropsychological test battery consisting of measures considered sensitive to either orbitofrontal or dorsolateral-prefrontal (DLPF) dysfunction. Orbitofrontal hypoarousal is associated with behavioral disinhibition and a relative indifference to punishment. The DLPF region may function as a central executive system. Indeed, DLPF dysfunction may underlie many of the cardinal symptoms associated with ADHD. We tested the following hypotheses: (1) adult subjects meeting DSM-IV criteria for ADHD, predominantly hyperactive-impulsive type, would display neuropsychological deficits on tasks sensitive to orbitofrontal dysfunction; (2) adult subjects meeting DSM-IV criteria for ADHD, predominantly inattentive type, would perform poorly on measures sensitive to DLPF dysfunction; and (3) adult subjects meeting DSM-IV criteria for ADHD, combined type, would exhibit performance deficits on orbitofrontal measures and on DLPF tasks. Results partially confirmed our hypotheses. Subtyping ADHD patients revealed important group differences. Distinct neurocognitive and clinical profiles were observed.

Adult↗

PubMedDate not supplied

Unexpected neurotoxicity in dogs receiving a cyclophosphamide, dactinomycin, and 5-fluorouracil chemotherapy protocol.

An inexpensive combination chemotherapy protocol containing cyclophosphamide, dactinomycin, and 5-fluorouracil was evaluated in dogs with carcinomas. Fifteen dogs were entered in this study, and there were 1 complete response and 2 partial responses among 12 evaluable dogs. However, 6 of 15 dogs (40%) developed neurotoxicity. The neurotoxicity of this protocol was compared with a previous 5-fluorouracil-containing protocol and found to be significantly higher. Due to the unacceptably high rate of neurotoxicity, this protocol cannot be recommended for use in dogs with cancer.

Animals↗

PubMedDate not supplied

Carotid blood velocity during cough studies in man.

Utilizing a Doppler ultrasonic flowmeter catheter, right carotid artery blood velocity was measured during 91 coughing episodes in 16 patients. Such coughing reduced carotid blood velocity by 40 +/- 22% (control = 34 +/- 8 cm per second, cough = 20 +/- 9 cm per second, p less than 0.001). There was an insignificant low degree of corrleation between the level of simultaneously recorded mean right pressure and the percent decline of peak carotid blood velocity, suggesting that impaired venous return was not the only factor responsible for the observed changes. It is concluded that (1)coughing diminishes phasic carotid blood velocity and (2)reduced cerebral perfusion may play a role in the pathogenesis of cough syncope.

Adult↗

PubMedDate not supplied

Primary T-cell lymphoma of oral cavity.

Immunopathologic studies classify lymphoma under the T-cell or B-cell groups. Such a classification gives a better indication for prognosis and treatment of lymphomas, with the T-cell group having the worse prognosis. A patient with a T-cell lymphoma of the oral cavity is presented. The diagnostic features and management are discussed.

Humans↗

PubMedDate not supplied

Aneurysms of an aorto-coronary artery saphenous vein bypass graft--a case report.

A 62 year old man with severe angina pectoris underwent aoroto-coronary saphenous vein graft implantation. After a four month asymptomatic period the patient underwent aorto-coronary graft angiography. Left anterior descending graft opacification demonstrated multiple venous aneurysmal dilations. The clinical significance of this finding is currently unknown but such saphenous vein disease warrants further investigation. Saphenous vein grafts have been utilized to replace or bypass obstructed and diseased peripheral arteries such as those of the carotid and femoral-popliteal vascular systesm. In 1967 Favaloro introduced the saphenous vein as a means for bypassing local obstructions in diseased coronary arteries of human subjects. Since the advent of the aorto-coronary saphenous vein bypass graft procedure several studies have reported pathologic alterations of these grafts at post-mortem examination or at the time of re-operation. Other investigators have also noted changes in these venous grafts when they have been implanted in peripheral vessels. We report here a patient with aneruysmal dilations of an aorto-coronary artery saphenous vein bypass graft. Furthermore, possible mechanisms which might produce such venous aneurysms and the clinical significance of such an entity are discussed.

Aneurysm↗