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Biomedical subjects

J Perry

Publications and source records attributed to J Perry.

At least 217 records · Page 12Linked to original sources
PubMed1985

Induction of IgA-specific suppressor activity in human T-lymphocyte cultures.

Cell-free supernatants of human circulating T-lymphocyte cultures incubated with secretory IgA (S-IgA) specifically suppressed both spontaneous IgA synthesis by B lymphocytes isolated from allergic individuals and pokeweek mitogen-induced IgA secretion by peripheral blood mononuclear cells. Cell-free supernatants of T-cell cultures incubated with IgE had no effect on IgA, IgG, or IgM synthesis. Hence, it is concluded that upon incubation with S-IgA, but not with another Ig class, T lymphocytes release IgA-specific suppressor factors.

Antibody Specificity↗
PubMed1985

Surreptitious warfarin ingestion.

Munchausen by proxy has been reported involving children who have been given various drugs or toxins. In addition, there is a body of adult literature regarding covert anticoagulant ingestion. This is a case of an 11-month-old female who appears to combine features of both of these syndromes. This child presented with an acute left hemorrhagic otitis media. The physical examination was unremarkable except for the following: weight, fifth percentile; left external auditory canal filled with blood with the right external canal and tympanic membrane being normal; and several scattered 1 X 2 cm firm, movable, nontender, purple nodules on extremities, chest and forehead. The coagulation studies were consistent with Vitamin K deficiency secondary to anticoagulant ingestion. A serum warfarin study confirmed our suspicions. The mother was noted to have a dependent relationship with her child and characteristics of those involved in Munchausen by proxy: falsifying information and thwarting medical assessment. In addition, she displayed some of the characteristics found commonly in anticoagulant malingerers. She was depressed, with limited medical knowledge, and had access to warfarin. The mother was admitted for inpatient psychiatric care and the patient placed with an extended family member. This case report describes the use of an anticoagulant to induce illness in a child by a psychologically ill mother. This form of child abuse must be considered in the differential diagnoses of hemorrhagic disorders.

Adult↗
PubMed1985

Rising from a chair. Influence of age and chair design.

We studied the effect of age on the act of rising from a standard armchair in a younger (means = 24 years) and an older (means = 75 years) group of healthy adult women. Rising from a standard armchair and an armchair specially designed for comfort in sitting of the elderly was studied in the older group to determine the influence of the special chair. We used electrogoniometry, EMG, and videotape analysis to record the activity for both groups. The older group placed their feet farther back and showed greater vastus lateralis muscle activity than did the younger group to rise from the standard chair. These results suggest that rising from the standard chair was more difficult for the older than for the younger group. In the special chair, the older subjects showed even more vastus lateralis muscle activity, greater knee flexion, and greater trunk forward lean. Rising from the special chair, therefore, appeared to be more difficult than rising from a standard chair; this finding suggests that both comfort and function must be considered in chair selection for certain groups.

Adult↗
PubMed1985

Walking patterns of healthy subjects wearing rocker shoes.

We compared walking in rocker shoes with walking in athletic shoes at free and fast velocities in 15 healthy women who were between the ages of 21 and 30 years. Footswitches, electrogoniometers, surface electromyograms, and a force plate were used for data collection. No significant differences were found in velocity, cadence, gait-cycle duration, single-limb support, or swing-stance ratios in free and fast walking. Double-limb support was decreased by 9% in the rocker shoes in free walking. The ankle range of motion showed accommodation of the foot to the 8.5 degrees of plantar flexion built into the rocker shoes. Electromyographic responses appeared to be similar regardless of shoes or cadence.

Adult↗
PubMed1985

Rate and range of knee motion during ambulation in healthy and arthritic subjects.

The purpose of this study was to determine the relationship between gait velocity and rate and range of knee motion, during ambulation, for healthy and arthritic subjects. The arthritic subjects had either rheumatoid arthritis or osteoarthritis, and all were tested before and after total knee replacement. Healthy subjects ambulated at an average velocity of 80 m/min and demonstrated knee flexion and extension rates of 344 degrees/sec and a range of knee motion of 60 degrees. Gait velocity correlated with rates of knee flexion and extension and range of knee motion. Arthritic subjects ambulated at velocities less than those of healthy subjects ambulating at free speed. Arthritic subjects accordingly demonstrated reduced knee flexion and extension rates and range of knee motion. When compared with healthy subjects ambulating over a comparable gait-velocity range, the arthritic subjects demonstrated reduced rates and range of motion in most instances. We discuss implications for therapeutic intervention to increase gait velocity for arthritic subjects.

Adult↗
PubMed1985

Has the discipline of nursing developed to the stage where nurses do 'think nursing'?

With the increasing complexity and changing conditions of nursing practice, as well as the encroachment of other professions on nursing's traditional domain, it is becoming increasingly important for nurses to gain insights into the nature of nursing knowledge and practice. This paper attempts to outline the meaning of the expression 'to think nursing' and the factors involved in such a capacity. The work of nurse scholars is then discussed in terms of their contribution towards developing the discipline of nursing to the stage where nurses do 'think nursing'.

Attitude↗
PubMed1985

Role of folate dependent transformylases in synthesis of purine in bone marrow of man and in bone marrow and liver of rats.

The activity of the two folate dependent enzymes supplying carbon 2 and carbon 8 of the purine nucleus was assayed in the bone marrow of rats and man, as well as in rat livers. The activity of both enzymes was several fold greater in marrow than in liver. Inactivation of cobalamin by exposure to nitrous oxide did not affect the enzymes in rat marrow cells, although an appreciable effect on hepatic enzymes was found. The depression of hepatic glycinamide ribotide (GAR) transformylase in rats exposed to nitrous oxide was prevented by supplying a formate precursor, methylthioadenosine. There was a considerable rise in the activity of GAR transformylase in human marrow cells from patients with megaloblastic anaemia due to cobalamin deficiency but no change in activity in marrow from patients deficient in folate.

Acyltransferases↗
PubMed1985

Functional demands on the stance limb in walking.

In normal human locomotion, the lower extremities must maintain the erect posture while at the same time permitting forward progression of the body. Walking involves a complex interplay of gravity, momentum changes, and muscle action. A quantitative analysis of the effects of gravity and momentum changes on the stance limb in normal gait has been performed. These effects, represented by the ground reaction force, impose challenges to the muscles of the lower extremity. The nature of the torques about the hip, knee, and ankle joints has been investigated and correlated with the timing of muscle action throughout the gait cycle. Mechanical events in the earliest part of stance phase have been more clearly described than in previous work. Analysis of the effects of gravity and momentum changes improves our understanding of the mechanics of normal walking, and can aid in the diagnosis and treatment of disabled patients.

Adult↗
PubMed1985

Polio: long-term problems.

The most common long-term problems seen in polio are brace problems, knee recurvatum, increasing weakness due to overuse and ankle equinus. A definite increased incidence of problems is seen after the patient is more than 30 years post-polio. The basis for most of these problems is chronic mechanical strain of weak musculature and substituting ligaments. Overuse can cause increasing weakness resulting in pain and decreasing function. It is therefore important to follow polio patients closely, especially those that are more than 30 years post-polio. If signs of overuse or chronic mechanical strain are noted, treatment should not be delayed.

Adolescent↗
PubMed1985

Functional evaluation of total hip arthroplasty with five- to ten-year follow-up evaluation.

Forty-seven patients with unilateral hip disease had a preoperative and postoperative gait analysis of total hip arthroplasty with a follow-up period of five to ten years. The object was to correlate the levels of function with mechanical loosening. Unilateral total hip arthroplasty in uncomplicated patients restored function to 80% of normal over a two- to four-year period. Patients followed longer than five years appeared to have an accelerated decline in function unassociated with pain. No Class C patient, regardless of age or gait velocity, developed loosening or required revision of the hip prosthesis. Survivorship studies revealed an 85%-90% incidence of loosening by the seventh postoperative year in Class A patients 55 years or younger and those walking preoperatively at more than 50% of normal gait velocity. In these same two groups of patients, the probability of revision for mechanical failure by ten years is 58% for age and 66% for fast walkers. The majority of patients in this study had a technical rating not acceptable by present standards so that these results represent most likely the worst prognosis for longevity of total hip arthroplasty. In high-risk patients, protected ambulation with crutches for six months postoperation may improve their prognosis.

Female↗
PubMed1985

Turnover of the methyl moiety of 5-methyltetrahydropteroylglutamic acid in the cobalamin-inactivated rat.

The metabolism of the methyl group of 5-methyltetrahydrofolate was studied in rats in which cobalamin had been inactivated by exposure to nitrous oxide and in air-breathing control animals. Methylfolate labeled with [14C] in the methyl group and with [3H] in the pteridine-PABA portion was injected and the disappearance of [14C]H3- relative to [3H]folate was measured in liver. The half-time of the methyl group in the livers of control rats was two hours. There was no turnover of the methyl group for the first 72 hours after cobalamin inactivation. After 72 hours, there was a slow turnover of the methyl group, with a half-time of 43 hours. In control rats, it is assumed that the methyl group was metabolized by transfer to homocysteine to form methionine. In cobalamin-inactivated rats, it was shown that methylfolate was used as the substrate for forming folate polyglutamate, and analogues with 3, 4, and 5 glutamic acid residues were present. It is likely that oxidation of the methyl group by methylene tetrahydrofolate reductase occurs from folate polyglutamate containing six and seven glutamic acid residues, (Brody et al, Biochemistry 21: 276, 1982), since we were unable to demonstrate labeled methyl in longer chain analogues.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1984

Gait analysis techniques. Rancho Los Amigos Hospital gait laboratory.

In the gait laboratory at Rancho Los Amigos Hospital, the emphasis is on patient testing to identify functional problems and determine the effectiveness of treatment programs. Footswitch stride analysis, dynamic EMG, energy-cost measurements, force plate, and instrumented motion analysis are the techniques most often used. Stride data define the temporal and distance factors of gait. We use this information to classify the patient's ability to walk and measure response to treatment programs. Inappropriate muscle action in the patient disabled by an upper motor neuron lesion is identified with dynamic EMG. Intramuscular wire electrodes are used to differentiate the action of adjacent muscles. We use the information to localize the source of abnormal function so that selection of treatment procedures is more precise. Force and motion data aid in determining the functional requirement and the muscular response necessary to meet the demand. Determining the optimum mode of locomotion and developing criteria for program planning have become more realistic with the aid of energy-cost measurements. Microprocessors and personal computer systems have made compact and reliable single-concept instrumentation available for basic gait analysis in the standard clinical environment at a modest cost. The more elaborate composite systems, however, still require custom instrumentation and engineering support.

Adult↗
PubMed1984

Ankle and subtalar motion during gait in arthritic patients.

The purposes of this study were 1) to document ankle and subtalar motion during gait in 20 healthy subjects and in 25 patients with rheumatoid arthritis (RA) and 2) to determine stride characteristics with and without the use of an extended University of California Biomechanics Laboratory orthosis in RA patients with painful ankle and hindfoot deformity. An insole foot-switch system and ankle and subtalar electrogoniometers measured stride characteristics and dynamic range of motion (ROM). Arthritic patients demonstrated less ROM than healthy subjects except for ROM of hindfoot valgus. Arthritic patients also had slower gait velocity and less single limb support (SLS) time. In five new and five current orthotic wearers, a significant increase (p less than .01) in velocity and SLS time occurred with shoes and a further significant increase (p less than .01) occurred with the orthosis. Nine of 10 patients reported a decrease in ankle and hindfoot pain after using the orthosis. This study demonstrates the value of an orthosis for the treatment of arthritic patients with ankle and hindfoot pain and deformity.

Adult↗
PubMed1983

Effects of nitrous oxide-induced inactivation of cobalamin on methionine and S-adenosylmethionine metabolism in the rat.

Inhalation of nitrous oxidises cobalamin and, in turn, inactivates methionine synthetase which forms methionine from homocysteine and which requires cob[I]alamin as a co-factor. This study was planned to determine the effect of virtual cessation of methionine synthesis via a cobalamin-dependent pathway, on tissue levels of methionine, S-adenosylmethionine and on related enzymes. The level of methionine in liver fell initially after exposure to N2O but was restored to pre-N2O levels after 6 days despite continuing N2O exposure. Brain methionine fell within 12 h of N2O exposure but the fall was not significant. The restoration of methionine levels is accompanied by an increase in activity of betaine homocysteine methyltransferase in liver but this enzyme was not detected in brain. The activity of methionine synthetase remained very low in both liver and brain as long as N2O inhalation was continued. There was an initial rise in liver S-adenosylmethionine levels followed by a steady fall to 40% of its initial level after 11 days of N2O exposure. However, there was no change in the level of S-adenosylmethionine in brain during this period. The data indicate that either brain meets its requirement by increased methionine uptake from plasma or that there are alternate pathways in brain for methionine synthesis other than those requiring a cobalamin coenzyme.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1983

Effect of nitrous oxide-induced inactivation of vitamin B12 on glycinamide ribonucleotide transformylase and 5-amino-4-imidazole carboxamide transformylase.

Exposure to nitrous oxide (N2O) in vivo is accompanied by oxidation of cob[I]-alamin to the inactive cob[III]alamin [1]. There is loss of methionine synthetase activity [2] and evidence of depressed supply of single carbon units at the formate level of oxidation [3,4,5]. We measured the effect of inactivation of B12 on the folate-dependent transformylases concerned in purine synthesis. After 24 h exposure to N2O there was a significant fall in glycinamide ribonucleotide transformylase (EC 2.1.2.2) and a significant increase in 5-amino-4-imidazole carboxamide transformylase (EC 2.1.2.3).

Acyltransferases↗