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Biomedical subjects

L Thorpe

Publications and source records attributed to L Thorpe.

32 records · Page 2Linked to original sources
PubMed1991

Plasma phenylethylamine in schizophrenic patients.

Plasma samples were collected from 41 patients who met DSM-III criteria for schizophrenia and from 34 healthy controls. Phenylethylamine (PE) levels were determined using a gas chromatography-mass spectrometry negative chemical ionization method. PE was significantly higher in the schizophrenic patients compared with controls. There were no differences in PE between paranoid and nonparanoid patients. Plasma PE did not appear to be influenced by the severity of schizophrenic symptoms (rated by BPRS, SANS, and SAPS) or by the amount of dietary phenylalanine ingested within 24 hr of testing. Plasma PE did not correlate with current or past exposure to neuroleptic medication. It was not possible, however, to test individual patients during two periods when they were taking and not taking medication. Thus it is possible that neuroleptic exposure may have confounded the results. This study provides further evidence that PE excess may play a role in the etiology of schizophrenia but does not support previous studies which suggest that such an abnormality is limited to the paranoid subgroup.

Adult↗
PubMed1991

Coronary arterial remodeling studied by high-frequency epicardial echocardiography: an early compensatory mechanism in patients with obstructive coronary atherosclerosis.

Coronary arterial remodeling is a compensatory mechanism that may limit the adverse effects of coronary obstructive lesions by expansion of the entire vascular segment. To determine if this compensatory anatomic change occurs in patients, high-frequency epicardial echocardiography using a 12 MHz transducer was performed during open heart surgery in 33 patients (10 with normal coronary arteries undergoing valvular surgery and 23 with coronary atherosclerosis). From stop-frame videotape high-frequency epicardial echocardiographic images, cross-sectional measurements of luminal area and total arterial area (lumen, intima, media and dense adventitia) were made in the patients with atherosclerosis at the site of arterial lesions and from the most proximal portion of the same artery. Remodeling was defined as enlargement of the total arterial area. In normal arteries measurements were made from proximal and midarterial locations. In the patients with normal coronary arteries, total arterial area, as determined by high-frequency echocardiography, decreased from the proximal site to the midportion of the artery (from 10.4 +/- 0.9 to 8.4 +/- 1.0 mm2, p less than 0.05); luminal area also decreased (from 6.0 +/- 0.6 to 4.5 +/- 0.7 mm2, p less than 0.05). In patients with coronary arterial lesions, luminal area also decreased from the proximal site to the arterial lesion site (from 5.3 +/- 0.6 to 2.3 +/- 0.3 mm2, p less than 0.05), but total arterial area increased (from 11.6 +/- 1.0 to 13.0 +/- 1.0 mm2, p less than 0.05). Of the 25 coronary arteries evaluated, only 4 had angiographic evidence of coronary collateral formation. These data indicate that coronary arterial remodeling is an important compensatory mechanism in obstructive coronary disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Surgical Procedures↗
PubMed1991

Developmental perspectives on the localization and detection of auditory signals.

Responsiveness of 1-, 3-, and 5-year-old children and adults to octave-band noises at .4 and 10 kHz was assessed with a go/no-go version of visual reinforcement audiometry (VRA) (Moore, Thompson, & Thompson, 1975) and a two-alternative, forced-choice version (Suzuki & Ogiba, 1961; Trehub, Schneider, & Endman, 1980). Infants performed better on the two-alternative, forced-choice version in quiet and in noisy backgrounds, and adults performed better on the two-alternative, forced-choice version in quiet but not in noisy backgrounds. Performance on the two tasks was essentially equivalent for 3- and 5-year-old children. Superior performance on two-alternative VRA over go/no-go may be due to lesser cognitive demands in the case of infants and to the engagement of superior decision strategies in the case of adults.

Adolescent↗
PubMed1988

Noninvasive imaging for deep venous thrombosis.

In 96 patients, 127 extremities were identified by duplex ultrasonography as having acute deep venous thrombosis. The majority of these patients were found to have factors that predisposed them to thrombi formation. Doppler examination correlated with the duplex results in 77 extremities (61 percent). Two factors were identified that led to discrepancies between the results of these two modalities: (1) Thrombi that were more proximally located and totally occlusive were more likely to result in abnormal Doppler results than those that were not. (2) Doppler examination of the deep venous system of the lower extremities, although more accurate than clinical evaluation, was of insufficient accuracy to make correct decisions regarding the need for anticoagulation.

Acute Disease↗
PubMed1988

The use of deep duplex scanning to predict hemodynamically significant aortoiliac stenoses.

Hemodynamic assessment of aortoiliac occlusive disease is necessary for successful arterial reconstruction of the aorta and legs. Various methods have been proposed and "pull-through" intra-arterial pressures are the "gold standard." Deep Doppler duplex imaging was supplemented with real-time spectral analysis and velocity measurements in 29 cases. Twenty-three of these patients needed arteriography. One hundred sixty-six (166) arterial segments extending from the proximal aorta to the common femoral arteries were independently graded on duplex scans and arteriograms. For severe occlusive disease, duplex scanning is highly accurate (sensitivity 82%, specificity 93%). Velocity measurements were useful in determining the hemodynamic significance of stenoses. Peak systolic velocities in stenoses were measured with a duplex scanner. The pressure gradient calculated with the modified Bernoulli equation (delta P = 4Vmax2) correlated well with the gradients measured during arteriography (r = 0.9, n = 11). These noninvasive velocity measurements and Bernoulli calculations alert arteriographers to obtain special views of suspected areas and suggest the need for "pull-through" pressures and possible balloon angioplasty. In addition, these noninvasive measurements are useful to follow up patients who have mild to moderate aortoiliac disease and after angioplasty.

Aged↗
PubMed1987

Duplex B-mode imaging for the diagnosis of deep venous thrombosis.

Real-time B-mode venous imaging has numerous advantages for the diagnosis of acute deep venous thrombosis (DVT). During the 11 months ending Feb 1, 1986, we examined 431 patients for possible acute DVT using a 5-MHz hand-held continuous wave Doppler stethoscope and a duplex real-time B-mode imager. Clots were seen in 86 patients in multiple views and cross sections. Normal veins completely collapsed with probe pressure on the skin. Blood flow was seen and heard, and abnormal flow was detected. There were no false-negatives (100% sensitivity). Early in the study, two false-positives occurred (78% specificity), but these errors will not recur. These tests are accurate, noninvasive, and inexpensive. They differentiate acute from chronic thrombosis and are repeatable. Duplex imaging may become the "gold standard" for the diagnosis of DVT.

Diagnostic Errors↗
PubMed1987

An automated medical record system for a skilled nursing facility.

This paper reports on the development of an on-line automated medical record system suitable for nursing homes. The software was written in standard MUMPS (Massachusetts General Hospital Utilities Multi-Programming System) and is easy for the first-time user to operate. The data managed by the system may be divided into four major components, including text tables, the hierarchical problem dictionary, the patient admission data, and the care plan data. The system met all of the project's objectives and has been enthusiastically received by the nursing home staff.

Medical Records↗
PubMed1987

Transient "pathological" Q-waves occurring during exercise testing: assessment of their clinical significance in a presentation of a series of patients.

Exercise-induced Q-waves were encountered in four Caucasian males presenting to the Cardiac Clinic, Tygerberg Hospital, with chest pain suggestive of angina pectoris. This phenomenon occurred in four out of a total of 1943 patients undergoing treadmill stress testing (Bruce Protocol) during a two-year period, giving an incidence of 0.21 percent of this ECG response. Two of the four patients (cases 1 and 2) were documented to have coronary atherosclerosis by selective coronary arteriography. One of these patients may well have been experiencing coronary vasospasm. One of the remaining two patients was a teenager whose exercise response was probably normal, whilst the last patient could have had ischemic heart disease (IHD). This most interesting and rare response to exercise (stress) testing is discussed, emphasis being placed on its incidence, mechanism and clinical significance in IHD and other conditions in clinical practice. Awareness of the occasional transient nature of "pathological" Q-waves, whether these occur at rest or during exercise, has an important bearing on such acute therapeutic interventions as intracoronary thrombolysis and percutaneous transluminal coronary angioplasty.

Adolescent↗
PubMed1986

Copper, zinc, and iron in normal and leukemic lymphocytes from children.

Copper, zinc, and iron were quantitated in the serum and lymphoid cells of the peripheral blood of healthy children and children with acute lymphocytic leukemia. Copper and iron concentrations in serum and cells were significantly higher and zinc concentration in the cells significantly lower in leukemic patients than in healthy donors, whereas the increase of zinc in the serum was not significant. The concentration of all minerals was higher in T-cell enriched preparations. There was a significant correlation between copper and iron and between copper and zinc, but not between iron and zinc in normal and leukemic lymphocytes. No correlation was demonstrated among the three minerals in the serum. There were no significant differences associated with ethnicity, age, sex, type of leukemia, or number of leukemic cells. However, a group of five children with non-B-, non-T-cell acute lymphocytic leukemia, nonreactive skin tests, and low serum immunoglobulins had high concentrations of copper and iron and low concentration of zinc in their leukemic cells. Since copper, zinc, and iron are associated with lymphocyte maturation and regulation of immune function, these new data will provide a tool for the study of the relationship between changes in concentrations of these metals and the modification of the immune response often present in hematologic cancers.

Child↗
PubMed1985

Exercise-induced ST-segment elevation possibly caused by coronary artery spasm. A case presentation and review.

A 36-year-old man with classic angina pectoris had marked ST-segment elevation (STE) in the inferior leads on stress-testing in the absence of chest pain. There was no evidence of previous myocardial infarction (MI). Selective coronary arteriography delineated severe obstructions in the right coronary artery (RCA) with additional left circumflex coronary artery (LCx) obstruction. Left ventricular cine-angiography established that there was normal contractility and confirmed the absence of past MI. Coronary artery bypass graft surgery to the RCA and LCx was unfortunately complicated by an acute transmural inferoposterolateral MI. Treadmill stress testing 6 weeks after surgery failed to demonstrate the preoperative ST-segment change. The patient may have developed exercise-induced coronary artery spasm superimposed on the severe proximal RCA stenosis; this in turn may have caused the inferior STE. Exercise-induced STE is reviewed.

Adult↗
PubMed1977

An improved method for purification of lymphocytes.

A method that combines glass-bead column filtration, Ficoll-Hypaque gradient separation, discontinuous sucrose gradient, and drastic reduction of cell transfers is described. The procedure gives a high yield of pure human lymphocytes from small amounts of blood, good preservation of B cell/T cell ratio, and sufficient material for subsequent biochemical studies.

Adolescent↗