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Biomedical subjects

D Russell

Publications and source records attributed to D Russell.

At least 217 records · Page 12Linked to original sources
PubMed1987

Transcription analysis of the maize chloroplast gene for the ribosomal protein S4.

Maize seedlings contain several RNA species complementary to the rpS4 coding strand of the maize chloroplast ribosomal protein gene rpS4. All of these have the same 5' end about 182 bp upstream of the translation start codon for the protein S4. Northern and S1 nuclease analyses of RNA isolated from seedlings at different stages of greening show that the size of the pool of rpS4 transcripts does not change significantly upon illumination of dark-grown seedlings. The rpS4 gene has also been analyzed by in vitro transcription using maize chloroplast RNA polymerase preparations. The site of initiation in vitro has been mapped by S1 nuclease analysis to the same location as the 5' terminus of in vivo transcripts. A sequence resembling other plastid promoters occurs just upstream of this initiation site. The sensitivity of in vitro transcription to DNA template superhelicity has been assessed for the rpS4 gene promoter; its negative superhelicity-transcription rate profile resembles that of rbcL.

Base Sequence↗
PubMed1987

Mediators of anaphylaxis-induced ion transport changes in small intestine.

Net ion transport by jejunum of rats immunized against Trichinella spiralis on challenge with parasite-derived antigen was measured in Ussing chambers as a rapidly expressed, biphasic rise and fall (phase I and II) in short-circuit current (delta Isc). This delta Isc is triggered by mucosal anaphylaxis. Our objective is to identify mast cell-derived substances that mediate the epithelial response. Antigenic challenge of sensitized jejunum caused the release of 5-hydroxytryptamine (5-HT), histamine, and prostaglandin E2 (PGE2). The antigen-induced phase I response was mimicked by exogenous 5-HT or histamine and blocked by pretreatment of tissue with 5-HT and histamine H1-antagonists; the phase II response was mimicked by exogenous PGE2 and blocked by an inhibitor of prostaglandin synthesis. Atropine and tetrodotoxin significantly blunted the phase I response as well as the delta Isc caused by exogenous 5-HT or histamine while only slightly reducing the phase II response and not affecting the delta Isc induced by PGE2. Results support the conclusion that 5-HT, histamine, and PGE2 mediate the antigen-induced change in Isc through direct and neurally mediated stimulation of jejunal epithelium.

Anaphylaxis↗
PubMed1987

Nursing home costs for those dually entitled to Medicare and Medicaid.

The focus of this article is the impact of nursing home care on total Medicare and Medicaid expenditures for the aged population entitled to both programs. To determine these costs for 1981, data in the Health Care Financing Administration's Medicare Statistical System were linked, for the first time, to data in the Medicaid system for four States. Also examined are expenditure patterns for survivors and decedents using nursing home services. Results indicate that the two most significant factors influencing costs or the dually entitled elderly are the use of nursing home services and the costs of care in the last months of life. An unexpected finding was that of the 73 percent who neither died nor were in a nursing home, per capita expenditures were remarkedly constant across all age groups.

Aged↗
PubMed1987

Leprosy.

Explore the source record for details and available documents.

Humans↗
PubMed1986

Pulsed Doppler echocardiographic study of left ventricular filling in dilated cardiomyopathy.

Patients with dilated cardiomyopathy (DC) have been reported to have abnormal left ventricular (LV) diastolic properties. To evaluate LV diastolic filling characteristics in patients with DC, pulsed Doppler echocardiography was used to study mitral flow velocity in 21 patients with DC and mitral regurgitation (MR), 12 patients with DC but no MR and 19 age-matched normal subjects. Diagnosis of MR was based on the Doppler echocardiographic finding of holosystolic turbulent flow in the left atrium. Peak mitral flow velocity in early diastole (PFVE) and during atrial systole (PFVA), PFVA/PFVE and deceleration half-time of early diastolic flow were measured from Doppler mitral flow velocity recordings. In 21 patients with DC and MR, PFVE (61 +/- 13 cm/s), PFVA (37 +/- 19 cm/s) and PFVA/PFVE (0.6 +/- 0.4) were not significantly different from PFVE (53 +/- 10 cm/s), PFVA (47 +/- 12 cm/s) and PFVA/PFVE (1.0 +/- 0.4) in normal subjects (p greater than 0.05). Deceleration half-time in DC patients with MR (62 +/- 32 ms) was shorter than normal (87 +/- 25 ms) (p less than 0.05). In contrast, PFVE (31 +/- 11 cm/s) was lower and PFVA/PFVE (1.7 +/- 0.8) was higher in the 12 DC patients without MR than in normal subjects and DC patients with MR (p less than 0.005). PFVA (46 +/- 8 cm/s) and deceleration half-time (88 +/- 33 ms) in patients without MR were not significantly different from normal mean values. Thus, abnormalities of peak diastolic mitral flow velocity were detected in DC patients without MR but not in DC patients with MR, suggesting that MR masks LV filling abnormalities in patients with DC.

Adult↗
PubMed1986

Effect of imaging view and sample volume location on evaluation of mitral flow velocity by pulsed Doppler echocardiography.

Pulsed Doppler mitral flow velocity measurements have been used to evaluate left ventricular diastolic filling. In normal persons these measurements are affected by age and respiration, but not by gender, body surface area or normal blood pressure. Additional factors that may influence these measurements include the imaging view and sample volume location. In this study, the effects of imaging view and sample volume location were evaluated in 52 normal subjects, aged 21 to 78 years. Pulsed Doppler recordings were obtained from the apical 4-chamber and apical 2-chamber views with the sample volume located both in the left atrium and at the level of the mitral valve leaflet tips. Doppler measurements were slightly, but not significantly, higher (4% on average) for recordings obtained from the apical 4-chamber than from the 2-chamber view for peak flow velocity in both early and late diastole. However, apical 4-chamber recordings from a sample volume in the left atrium resulted in measurements significantly lower (p less than 0.05) for both early and late diastolic mitral peak flow velocity than those obtained near the mitral leaflet tips (peak flow velocity in early diastole = 43 +/- 12 vs 57 +/- 12 cm/s and peak flow velocity in late diastole = 36 +/- 7 vs 46 +/- 11 cm/s, respectively). The higher mitral peak flow velocity values recorded in early and late diastole near the mitral leaflet tips may be related to the smaller flow area at the mitral valve orifice compared with the left atrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

A simple Doppler echocardiographic method for estimating severity of aortic regurgitation.

Doppler echocardiography is useful for detecting aortic regurgitation (AR). To determine if the presence of retrograde holodiastolic flow in the abdominal aorta can be used to assess the severity of AR, abdominal aortic flow velocity was examined by pulsed Doppler echocardiography in 33 patients with AR and 10 patients without AR confirmed by aortography, and in 15 normal subjects. Among the 33 patients with AR, 15 had mitral regurgitation, 11 had mitral stenosis, 8 had aortic stenosis, 5 had prosthetic mitral valves, 4 had prosthetic aortic valves and 2 had aorticopulmonary shunts. No retrograde holodiastolic flow was found in the abdominal aorta of 15 normal subjects or 10 patients without AR. Of the 22 patients with 1+ or 2+ AR independently determined by injection of iodinated contrast into the aortic root, 21 did not have retrograde holodiastolic abdominal aortic flow, whereas all 11 patients with 3+ or 4+ AR had retrograde holodiastolic flow in the abdominal aorta. One patient with 1+ AR and a left-to-right aorticopulmonary shunt had retrograde holodiastolic flow in the abdominal aorta. The finding of holodiastolic retrograde flow in the abdominal aorta is useful for distinguishing patients with severe AR from those with mild or absent AR. Moreover, the method is easy to perform and results appear to be independent of the presence of other cardiac diseases except significant aorticopulmonary shunt.

Adolescent↗