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Biomedical subjects

C Higgins

Publications and source records attributed to C Higgins.

At least 55 records · Page 3Linked to original sources
PubMed1991

Stride-dependent changes in gait of older people.

Infrared computerized stroboscopic photometry was used to measure the kinematic profile of walking of 20 young adults and 20 neurologically healthy elderly people. Compared with the young adults, the elderly exhibited 17-20% reductions in the velocity of gait and length of stride. The elderly also exhibited comparable reductions in the maximum toe-floor clearance, arm swing, and rotations of the hips and knees, but these alterations in gait were attributable to the reduction in stride length, which may have non-neurological causes. The influence of reduced gait velocity and stride length on the other characteristics of walking must be considered when evaluating the pattern of walking in elderly people.

Adult↗
PubMed1990

Primary writing tremor. A form of focal dystonia?

Five patients exhibited severe tremor in the upper extremity, primarily when attempting to write or draw. Electromyography was performed to determine the patterns of muscle activity that were responsible for this tremor. Tremor was measured with an accelerometer and with a digitizing tablet. Two patients had postural tremor that was indistinguishable from mild, high-frequency essential tremor. All patients exhibited a severe 5-7-Hz tremor during the acts of writing and drawing. Muscles throughout the affected extremity exhibited rhythmic 5-7-Hz bursts of motor unit discharge, and the average level of motor unit activity was tonically increased in antagonistic muscles. This abnormal coactivation of antagonistic muscles produced subtle dystonic posturing of the affected limb that was overshadowed by severe tremor. Electromyography was useful in confirming the coexistence of tremor and dystonia in our patients. The nonspecificity of dystonia and postural tremor must be considered when discussing the nosology and pathophysiology of primary writing tremor.

Adult↗
PubMed1990

Quantification of tremor with a digitizing tablet.

Handwriting and drawing are commonly employed in the clinical assessment of tremor. These tasks have been quantified heretofore by subjective rating schemes, which are incapable of providing precise measures of the amplitude and frequency of tremor. A commercially-available digitizing tablet and personal computer can be interfaced so as to reliably record any pathologic tremor that is induced by writing or drawing. Numerical differentiation and spectral analysis can be used to conveniently quantify the amplitude and frequency of tremor. However, digitizing tablets lack sufficient sensitivity to measure physiologic tremor.

Handwriting↗
PubMed1990

31P magnetic resonance spectroscopy of pressure overload hypertrophy in rats: effect of reduced perfusion pressure.

STUDY OBJECTIVE - The purpose of the study was to confirm the presence of abnormalities in the coronary vessels of hypertensive hearts, and to examine the effects of reduced coronary perfusion pressure. DESIGN - Rats were made hypertensive by aortic banding, after which coronary flow and myocardial energy metabolites were studied in isolated hearts at physiological (140 cm H2O) and reduced (80 cm H2O) coronary perfusion pressures and compared with normotensive controls. SUBJECTS - Wistar-Kyoto rats between 250 and 300 g were used. Left ventricular hypertrophy was generated by aortic banding in 29 rats; 8 were studied one week after banding, and 21 three weeks after banding. There were 45 controls. MEASUREMENTS and RESULTS - Energy metabolites were assessed using 31P magnetic resonance spectroscopy, standardised by high performance liquid chromatography of rapidly freeze clamped tissue. Left ventricular wall thickness was determined using two dimensional echocardiography. Coronary flow (normalised for heart weight) was reduced significantly after one and three weeks of left ventricular hypertrophy, and at either physiological or below physiological pressures. Hearts from aortic banded animals developed higher intraventricular pressure with reduced oxygen consumption when perfused at a physiological pressure, indicating increased thermodynamic efficiency. When perfused at reduced pressure, the developed pressure declined significantly in both the one week and the three week banded groups compared to normal hearts. The phosphorylation potential and intracellular pH (pHi) were not significantly lower after one week and three weeks of left ventricular hypertrophy when perfused at physiological pressure. When perfused at reduced pressure, phosphorylation potential declined significantly in both groups of hypertrophied hearts, whereas pHi declined significantly only in the three week hypertrophy group. CONCLUSIONS - There is improved thermodynamic efficiency of the hypertrophied myocardium when perfused at a physiological pressure, but when perfused at a reduced pressure, ventricular function, phosphorylation potential and pHi decline in rat hearts after three weeks of aortic constriction, indicating an impairment of coronary reserve.

Animals↗
PubMed1988

Mechanics and energetics of overstretch: the relationship of altered left ventricular volume to the Frank-Starling mechanism and phosphorylation potential.

Isovolumic perfused rat hearts containing an intraventricular balloon were used to assess the effects of incremental balloon volumes on developed pressure, oxygen consumption, coronary flow, phosphorylation potential obtained by P-31 nuclear magnetic resonance, wall thickness obtained by two-dimensional echocardiography, and diastolic wall stress. Three phases in developed pressure were noted: (1) volumes from 0 to 150 microliter resulted in a continuous increase in developed pressure; (2) with volumes from 150 to 250 microliter, developed pressure remained constant whereas developed (systolic) and diastolic wall stress rose sharply; and (3) with volumes from 250 to 400 microliter, developed pressure fell whereas developed (systolic) and diastolic wall stress continued to rise. The ln [(PCr)/(Pi)] was in synchrony with oxygen consumption at 0 and 50 microliter balloon volumes, and then diverged at volumes greater than 100 microliter. Oxygen consumption increased from 0 to 50 microliter, was constant from 50 to 250 microliter balloon volume, and then declined. The ln [(PCr)/(Pi)] fell precipitously at balloon volumes greater than 100 microliter, most likely limited by oxygen consumption. Coronary flow did not change significantly until 250 microliter or more of water was added to the balloon, and then it started to decline. Volumes greater than 100 microliter result in overstretch of myofibers, as observed by the precipitous decline in ln [(PCr)/(Pi)], and the steep increase in diastolic wall stress. With excessive volume loading, the drop in phosphorylation potential, ln [(PCr)/(Pi)], appears to contribute to the decrease in developed pressure.

Adenosine Triphosphate↗
PubMed1988

Reproductive studies of NY-198 in rats. I. Fertility study.

Lomefloxacin (NY-198), a new antibacterial agent, was administered daily by gavage to groups of 22 male and 22 female rats at dosages of 30, 100 or 300 mg/kg/day. Males were dosed for 71 days before pairing and then until termination, and females were dosed for 15 days before pairing, throughout mating and until Day 7 of gestation. Females were killed on Day 20 of gestation for examination of their uterine contents. Males were killed after approximately 14 weeks treatment and their reproductive organs were weighed and retained. At 300 mg/kg/day the majority of animals showed increased salivation, water intake was slightly increased throughout the treatment period in males and before pairing in females whereas food intake showed a slight, transient reduction during the first few days of treatment in both sexes. Body weight gain of males was marginally depressed during the first week of treatment, but no other signs of reaction to treatment were observed. At 30 and 100 mg/kg/day some animals exhibited increased salivation after being dosed. At all dosages, NY-198 was without adverse effects upon mating performance and fertility, or upon survival, growth and development in utero. On the basis of the above results it is considered that the no effect level with respect to reproduction and breeding performance of treated F0 animals and the in utero development of the foetuses was 300 mg/kg/day. A dosage of 100 mg/kg/day was considered to be the no effect level for somatic changes in the F0 animals, and even at the highest dosage of 300 mg/kg/day only slight effects were recorded on the F0 animals.

4-Quinolones↗
PubMed1988

Reproductive studies of NY-198 in rats. III. Perinatal and postnatal study.

Lomefloxacin (NY-198), a new antibacterial agent, was administered daily by gavage to groups of 22 pregnant female rats of the CD strain at dosages of 30, 100 or 300 mg/kg/day from Day 17 of gestation to Day 21 of lactation. Females were allowed to deliver their litters and the offspring were examined for growth and functional development. There was a slight maternal response at the highest dosage (300 mg/kg/day), including increased salivation after dosing, reduced food intake in the treated period of gestation and increased water intake during the lactation period. Gestation length was slightly increased, although remaining within the laboratory background control range; in consequence, body weight of F1 offspring at Day 1 post partum was slightly increased. At 100 mg/kg/day, a few females showed increased salivation after dosing and there was a slight increase in gestation length. Birth weight of F1 offspring was slightly increased at 30 and 100 mg/kg/day but all values were within laboratory background control ranges. The survival, functional responses and fertility of F1 offspring were essentially unaffected by NY-198. On the basis of the above results, 30 mg/kg/day was considered to be the no-effect level for the F0 females treated during late gestation and lactation whilst 300 mg/kg/day administered to the F0 females had no adverse effect upon their offspring.

4-Quinolones↗
PubMed1987

Stretch reflex oscillations and essential tremor.

Using a computer-controlled torque motor and manipulandum, 50 ms torque pulses and 70 second trains of binary pseudorandom torque disturbances were applied to the wrists of 10 adult controls and 22 patients with essential tremor in order to study the interaction between mechanically-induced stretch-reflex oscillations and essential tremor. These two oscillations were separated by applying inertial and spring loads to the wrist. There was no evidence of increased or unstable stretch-reflex activity in the essential tremor patients, and stretch-reflex latencies did not correlate with the frequency of essential tremor. Essential tremor and mechanically-induced stretch-reflex oscillations are separate phenomena capable of complex interaction.

Adult↗
PubMed1986

Lymphoblastic lymphoma in adults.

Fifty-one patients with lymphoblastic lymphoma (LBL) treated with one of five successive intensive chemotherapy protocols for acute lymphoblastic leukemia (ALL) since 1971 were reviewed. The patients were divided into leukemic and nonleukemic groups, and their clinical and laboratory parameters compared. The projected 5-year survival rate for all patients treated with the L10/17 protocols was 45% for both leukemic and nonleukemic LBL. The response to treatment was compared with that of 111 patients with ALL and was nearly identical. Poor prognostic factors were age beyond 30, WBC greater than 50,000/microL, failure to achieve a complete response (CR), and a late CR during induction. Leukemia at presentation, T cell surface markers, and the presence of a mediastinal mass did not adversely affect survival. The use of intensive chemotherapy protocols has proven to be a significant advance in the treatment of LBL.

Adolescent↗
PubMed1986

Inhibition of testicular LDH-X from laboratory animals and man by gossypol and its isomers.

The inhibitory effect of (+)-, (-)-, (+/-)-gossypol and (+/-)-gossypol acetic acid upon testicular cytosolic LDH-X was measured in vitro. Gossypol acetic acid (0-100 mumol/l) inhibited LDH-X prepared from the testes of the mouse greater than rabbit greater than human greater than rat greater than hamster. There was no relationship between inhibition and in-vivo antifertility activity. LDH activity measured in vitro in serum of men and hamsters was unaffected by gossypol. Gossypol and its isomers were non-competitive inhibitors of human and hamster LDH-X with respect to the coenzyme NADH, competitive inhibitors of human LDH-X and noncompetitive-competitive inhibitors of hamster LDH-X with respect to the substrate alpha-ketobutyrate. Co-incubation with human serum albumin or poly-L-lysine but not lysine protected human and hamster LDH-X from gossypol.

Animals↗
PubMed1984

Terminology and anatomy of angulated coronary arteriography.

Angulated views in coronary arteriography have been increasingly utilized because of their superiority in demonstrating lesions not well seen in standard right and left oblique projections. The importance of these angulated views has been repeatedly demonstrated. It is the purpose of this article to review some basic coronary anatomy angulation terminology, and then to describe the particular advantages of the angulated views in coronary arteriography. Illustrations of these particular views of both coronary systems will be provided.

Angiography↗
PubMed1984

Primary therapy of acute promyelocytic leukemia: results of amsacrine- and daunorubicin-based therapy.

Remission rates for patients with acute promyelocytic leukemia (APL) have improved with the use of anthracyclines and proper management of disseminated intravascular coagulopathy. In a prospective randomized trial of chemotherapy in patients with acute nonlymphoblastic leukemia, there were 16 patients with APL. All 7 of the patients receiving the amsacrine-containing regimen and 5 of 9 receiving the daunorubicin-containing regimen achieved a remission. All patients, except 2 of the 3 who underwent bone marrow transplantation, remain alive and in remission from 1+ to 25+ mo. Amsacrine is an effective replacement for daunorubicin in the treatment of APL, and its use does not compromise the favorable remission duration characteristic of APL.

Adult↗
PubMed1984

Arthrographic studies in painful hemiplegic shoulders.

The rehabilitation of hemiplegic patients is often prolonged by the problem of painful shoulder. The specific etiology of this problem is controversial and treatment does not always produce the desired results. Thirty hemiplegic patients with painful, stiff ipsilateral shoulder joints were studied. The mean interval from the onset of stroke to the onset of painful shoulder was 3 months. On shoulder arthrography, 23 patients had capsular constriction typical of frozen shoulder (adhesive capsulitis). Seven patients had normal arthrograms. None showed rotator cuff or capsular tears. Electromyography revealed electrical silence in the shoulder musculature at rest. These findings indicate that the painful, stiff shoulder developing after hemiplegia is not caused by rotator cuff tear or by spasticity, but probably has a pathogenesis similar to that of idiopathic frozen shoulder.

Adult↗
PubMed1983

Pulmonary blood volume: analysis during exercise in patients with left ventricular dysfunction.

Recent reports have demonstrated substantial increases in pulmonary activity during radionuclide stress exercise studies in patients with coronary heart disease. These studies have shown that the degree of the increase reflected the severity of the underlying disease. We studied the effects of supine exercise on systolic function and pulmonary activity in ten normal control subjects and 20 patients with congestive cardiomyopathy (12 ischemic and 8 idiopathic). Ejection fraction rose in the normals (P less than 0.001), end-diastolic volume increased slightly but significantly (P less than 0.05), and pulmonary activity rose by less than 16%, (mean 10%) while cardiac output increased by 162%. On the other hand, the myopathy patients demonstrated a small increase in cardiac output, (+49%) with a more substantial increase in pulmonary activity (+25%, P less than 0.05 vs normals). In these patients, ejection fraction did not change during exercise, while end-diastolic and end-systolic volumes rose. In the myopathy patients, the cause for an increase in cardiac output was a rise in heart rate, with little change in stroke volume. We conclude that pulmonary activity rises in myopathy patients to a greater extent than in normal controls. This probably reflects the greater elevation in filling pressures these patients need to maintain forward cardiac output.

Adult↗
PubMed1983

Mechanism of increase in left ventricular end-diastolic pressure after contrast ventriculography in patients with coronary artery disease.

Elevation in left ventricular (LV) end-diastolic pressure (EDP) after contrast ventriculography (CV) has been proposed as a form of stress intervention in patients with coronary artery disease (CAD). The mechanism of this change has not been delineated. Accordingly, we performed two studies in CAD patients. In study 1 (n = 10), CV was repeated 3 minutes after an initial study. LVEDP rose from 14.9 +/- 6.6 mm Hg prior to the first ventriculogram to 26.9 +/- 10.8 mm Hg 3 minutes after the first ventriculogram (p less than 0.05) and immediately prior to the repeat CV (performed to evaluate the changes in volume produced by the first ventriculogram). In four patients with LV micromanometer pressures, the entire diastolic pressure-volume relation was shifted upward. LV ejection fraction (EF) and end-diastolic volume (EDV), peak LV pressure, and peripheral vascular resistance were unchanged at the time of repeat CV, and there was no correlation between the change in EDP and any of these variables. In study 2 (n = 6), gated radionuclide angiography was performed prior to and at minutes 2 to 7 after CV as were measurements of LV and right ventricular (RV) pressures. While both LV and RV EDP rose following contrast ventriculography, LV and RV EDV and EF were unchanged. We conclude that alterations in LVEDP after CV are unrelated to changes in LV or RV EDV and are most likely mediated by a decrease in myocardial compliance.

Adult↗