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Biomedical subjects

A Marcus

Publications and source records attributed to A Marcus.

At least 127 records · Page 7Linked to original sources
PubMed1970

Protein chain initiation by methionyl-tRNA in wheat embryo.

The mechanism of protein chain initiation has been investigated in a cell-free amino acid incorporation system from wheat embryos dependent on tobacco mosaic virus RNA. Analysis of the N-termini of the labeled peptide products of short-term incubations showed the presence of unblocked methionine. In addition, methionyl-tRNA (Met-tRNA) could be bound to ribosomes at 1.3 mM Mg(++) in a reaction requiring viral RNA, ATP, GTP, and soluble protein factors. Incorporation experiments with the two cytoplasmic Met-tRNAs of wheat germ, an initiating species designated Met-tRNA(i) and a Met-tRNA(m), showed that methionine transfer from Met-tRNA(i) was linear from zero time, while that from Met-tRNA(m) occurred only after an appreciable lag. Analysis of the peptide products showed that methionine transfer from Met-tRNA(i) was predominantly N-terminal. In contrast, methionine transfer from Met-tRNA(m) was exclusively into internal positions. Similar selectivity was observed in the ribosome binding assay; only Met-tRNA(i) showed a strong reaction. These experiments provide strong evidence that in the wheat embryo, cytoplasmic Met-tRNA(i) functions without formylation in the initiation of protein synthesis.

Amino Acids↗
PubMed1969

Polyribosome isolation in the presence of diethyl pyrocarbonate.

Isolation of polyribosomes from wheat embryos and corn root tips in the presence of diethyl pyrocarbonate showed this reagent to have a protective effect on polyribosome structure. In addition, the use of diethyl pyrocarbonate allowed initial homogenization to be performed under less stringent conditions than those normally employed for polyribosome isolation. The use of the reagent is however limited, in that it is deleterious to in vitro ribosomal amino acid incorporation.

Amino Acids↗
PubMed1969

Poisons at work.

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Lead Poisoning↗
PubMed1969

Poisons at work.

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Environmental Exposure↗
PubMed1966

Protein Synthesis in Imbibed Seeds III. Kinetics of Amino Acid Incorporation Ribosome Activation, and Polysome Formation.

The kinetics of development of protein-synthesizing capacity in the imbibing wheat embryo, were studied both in vivo and in vitro. During the first 30 minutes of imbibition protein-synthesizing capacity rises rapidly, lagging about 10 minutes behind water uptake. This rise in synthesizing capacity is accompanied by an increase in polysome content. As imbibition continues, both protein-synthesizing capacity and polysome content increase. With embryos from aged seed, the rate of protein synthesis is initially limited by another, presumably nonribosomal, reaction.

Journal Article↗
PubMedDate not supplied

Patient-reported experience with Velosulin human insulin in continuous subcutaneous insulin infusion.

A multicenter, retrospective survey of 339 patients with insulin-dependent diabetes mellitus was done to evaluate patient experience with Velosulin Human insulin, a regular insulin in a phosphate buffer, used in continuous subcutaneous insulin infusion. Patients had used this insulin exclusively for 3 months preceding the survey. Responses were elicited through interviews conducted by physicians or nurses. Patients were queried as to the occurrence of specific complications associated with pump therapy that occurred while using Velosulin Human insulin, including hypoglycemia, diabetic ketoacidosis, unexplained hyperglycemia, tubing obstruction, and infection or abscess at the infusion site. Most patients reported that they did not experience any of these complications during the preceding 3 months. The most frequently cited complication was hyperglycemia unexplained by dosage, exercise, or dietary changes, reported by 110 (32%) patients. The second most frequently reported complication was tubing obstruction, reported by 99 (29%) patients. The reported frequencies of the other complications were: severe hypoglycemia, 45 (13%) patients; diabetic ketoacidosis, 28 (8%) patients; and infection or abscess at the infusion site, 26 (8%) patients. The low morbidity reported by the patients in this survey probably was due in large part to careful patient selection, a high level of motivation on the part of the patients, and experience and education on the part of the health care team, as well as to the use of buffered regular human insulin.

Adolescent↗
PubMedDate not supplied

Testing different formats for communicating colorectal cancer risk.

This study assessed the extent to which different formats of informing men and women age 50 and over of the risks of colorectal cancer (CRC) affected their perceptions of their absolute and comparative (self versus other) 10-year and lifetime risks; emotional reactions about getting CRC; and screening intentions. Forty-four men and 78 women received information about the absolute lifetime risk of getting CRC. In addition, participants either did or did not receive information about (1) lifetime risk of getting CRC compared with other cancers, and (2) risk factors for CRC (age and polyps). Participants who received risk factors information were more likely to increase their perceived absolute 10-year and lifetime risks of getting CRC compared with participants who did not receive risk factors information. In addition, participants who received risk factors information were more likely to believe age was related to getting CRC and felt at greater risk for having polyps compared with participants who did not receive this information. None of the experimental conditions affected how worried, anxious, and fearful participants felt about getting CRC, nor did they affect screening intentions. Independent of experimental condition, participants tended to increase their intentions to get screened for CRC in the next year or two. Intention to be screened was more pronounced among participants who had been screened via a fecal occult blood test (FOBT) or sigmoidoscopy (SIG). Implications for the design of interventions involving the communication of CRC risks are discussed.

Colorectal Neoplasms↗
PubMedDate not supplied

Diagnosis of symptomatic postmenopausal women by traditional Chinese medicine practitioners.

OBJECTIVE: To learn more about the way that practitioners of traditional Chinese medicine (TCM) diagnose women who have menopausal symptoms. DESIGN: We assembled a cohort of 23 postmenopausal women who had hot flushes and were otherwise healthy. Each woman was examined independently by nine practitioners of TCM on the same day. Examination consisted of medical history and physical examination. Diagnoses were recorded and counted. RESULTS: The most frequent diagnosis made by the practitioners of TCM was kidney yin deficiency, which was the diagnosis made after 168 of 207 visits (81%); 23 women seen by nine TCM practitioners. Practitioners showed good agreement regarding presence of kidney yin deficiency: in 12 women (52%), this diagnosis was made by eight of nine practitioners; in 16 women (70%), seven of nine practitioners made this diagnosis; and in all 23 women (100%), at least five of nine practitioners made this diagnosis. CONCLUSIONS: Practitioners of TCM who diagnose postmenopausal women with vasomotor symptoms are likely to make a diagnosis that includes kidney yin deficiency.

Adult↗
PubMedDate not supplied

From soma to psyche: the crucial connection. Part 2. 'Cross-cultural medicine' decoded: learning about 'us' in the act of learning about 'them'.

UNLABELLED: The scorpion's bite--a culturally inept response to a medical emergency. Margaret Clark's criteria--keys to cultural barriers in medical care. Clifford Geertz's injunction: to view the culturally "different" as mirrors of the unacknowledged self. The case of José--scandal of his "compartmentalized" treatment. QUESTION: How much context may a physician be willing to absorb? Shawcross's The Quality of Mercy: western medical teams in Cambodian refugee camps--their good intentions versus their ethnocentric gaffes. The elderly as avatars of a "culture within a culture." Their beliefs, fears, dreams, and intimations--a "terra incognita" for service providers. Sardonic recoil against them (as in Shem's novel House of God) by residents--a professionally sanctioned response, deflecting what might otherwise be unendurable demands on their varied quotas of pity. Sisela Bok's moral claims: (1) for the integrity of decision making among the sick; (2) for the autonomy of the "dying response" among the aged. Steinberg's The Ethnic Myth: indictment of those using cultural difference to "explain" (or rationalize) health--and other--deficits rooted in historic, social, or economic inequity.

Aged↗