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At least 19 recordsLinked to original sources
PubMed1992

A comparison of a two-wheeled walker and a three-wheeled walker in a geriatric population.

OBJECTIVE: There are few data on the effect of walkers on gait and mobility or on comparisons of different walker types. We compared a commonly used 4-legged, 2-wheeled walker and a newer 3-legged, 3-wheeled walker in measures of gait, mobility, and patient satisfaction. DESIGN: Cross-over controlled trial. SETTING: In the Physical Therapy Department of a Veterans Affairs hospital. PARTICIPANTS: Subjects were 15 male and female frail elderly veterans (mean age, 82 years), both inpatients and outpatients, consecutively enrolled from a sample of 35 patients referred to the Physical Therapy Department for mobility problems. Subjects met the following criteria: age 65 or over, ambulatory, no prior use of a wheeled walker, stable medical condition, and informed consent. INTERVENTION: Subjects were evaluated without either walker and with each of the two walkers on a 15-foot walkway and a 60-foot obstacle course. Subjects were asked which walker they preferred. OUTCOME MEASURE: Outcome measures were stride length on the walkway, time on an obstacle course, and walker preference. RESULTS: Stride length was 1.4 inches (3.6 cm) greater with the 3-wheeled walker than with the 2-wheeled walker (P = 0.016 by Wilcoxon signed-rank test). Time on the obstacle course was 16.0 seconds less with the 3-wheeled walker than the 2-wheeled walker (P = 0.002). The 3-wheeled walker was subjectively preferred. CONCLUSIONS: The 3-wheeled walker appears to have a greater positive impact on gait and mobility than the 2-wheeled walker.

Activities of Daily Living↗
PubMed1978

The retention of circulating Walker-256 cells by Walker-256 tumours.

When Walker-256 cancer cells are injected into the portal veins of rats bearing Walker-256 tumours in their livers, the retention of the injected cancer cells by the tumours is considerably less than in the surrounding liver. After applying defined general criteria for "homing" phenomena to the data, it is concluded that compared with the liver, they demonstrate "antihoming". The observations are explained in terms of a deficient arrest process within the tumours.

Animals↗
PubMed1977

Influence of an infant walker on onset and quality of walking pattern of locomotion:an electromyographic investigation.

Acquisition of bipedal locomotor skill in human infants was studied electromyographically with regard to the deprivation or enrichment behavior resulting from the frequent and regular use of an infant walker. Subjects were six sets of male, fraternal twins. One randomly selected sibling from each set underwent a training program, commencing at the age of 300 days, spending a total of 2 hr. per day in a walker. Siblings not included in this group were subjected to no special training. EMG recordings were taken of all subjects at specified intervals in order to establish a model of the typical motor pattern at various stages of skill development. These data were then contrasted with EMG data similarly obtained from the walker-trained subjects. Use of an infant walker modified the mechanics of the infant's locomotion in a number of important ways. It was shown that use of the walker enables an infant to commit substantial mechanical errors yet succeed in bipedal locomotion. Inasmuch as the mechanics of walker-assisted and non-assisted bipedal locomotion are dissimilar in so many important ways, positive transfer from walker-training appears questionable.

Child Development↗
PubMed1990

Walker-related burns in infants and toddlers.

During one year, four (6.5%) of the 61 children who were hospitalized for burns at a children's hospital sustained their injuries in a walker. Records from a total of nine children hospitalized with walker burns were compared to those from other hospitalized burned children. Patients who were burned while in a walker had a greater body surface area burned (11.6%) than those with burns from abuse (1.7%), neglect (2.5%), or other accidents (6.2%). A higher percentage of males were burned, and the burn patterns differed among all four groups. Seven of the nine walker burns resulted from scalds, with three scalds from hot grease. Walker-related burn patients required more physical or occupational therapy and a longer mean hospital stay. Social histories of infants with walker and other accidental burns differed from those associated with abuse or neglect. Walkers expose infants to unnecessary hazards, including potentially serious burns; their use should be discouraged.

Accidents, Home↗
PubMedDate not supplied

In vitro effects of bone- and platelet-derived transforming growth factor-beta on the growth of Walker 256 carcinosarcoma cells.

Conditioned media from fetal rat calvarial cultures has previously been shown to stimulate the growth of the bone-metastasizing Walker 256 carcinosarcoma cell line. In the current investigation we looked at the possibility that transforming growth factor-beta (TGF-beta), present in conditioned media, and positively correlated with resorption in vitro, may be responsible for the enhanced proliferation of Walker cells cultured in these conditioned media. Purified platelet-derived TGF-beta produced a dose-dependent growth response in Walker cells with an ED50 equal to 0.05 ng/ml. Bone-derived TGF-beta activity in conditioned media, measured by NRK fibroblast colony formation, correlated well with percentage resorption in bone cultures, and growth activity in Walker cell culture. In addition to this, the growth response normally seen with conditioned media cultures of Walker cells was significantly inhibited by the addition of anti-TGF-beta 1 neutralizing antibody. We conclude that TGF-beta is an important growth stimulatory component from fetal rat calvaria.

Animals↗
PubMed1991

The Walker 256 carcinoma: a cell type inherently sensitive only to those difunctional agents that can form DNA interstrand crosslinks.

The Walker 256 rat tumour has been maintained in vivo for over 60 years and until recently was used as a primary screen for new antitumour agents. This screen was particularly useful in identifying difunctional alkylating agents as potentially useful anticancer agents and it would seem that the Walker tumour is composed of cells sensitive towards this type of agent. A cell line (WS) established from the Walker tumour retained the sensitivity of the tumour towards difunctional agents and we have examined its phenotype in comparison to a derived, resistant, cell line (WR). The response of WR cells to a range of cytotoxic agents was similar to other established cell lines whilst WS cells were much more sensitive only towards difunctional reacting agents. There were no significant differences in the binding of these agents to the DNA of WS or WR cells. All the agents towards which WS cells showed sensitivity were, without exception, capable of reacting with DNA in Walker cells and forming DNA-DNA interstrand crosslinks. WS cells were not sensitive to busulphan, BCNU, CCNU or Me-CCNU but these agents did not produce interstrand crosslinks in the DNA of either WS or WR cells. Thus WS cells are intrinsically sensitive to specific DNA damage and this is probably a DNA interstrand crosslink. Hybrid cells produced by fusion of WS with WR cells lacked the inherent sensitivity of the WS cells towards cisplatin; sensitivity was therefore a recessive characteristic. Transfection of WS cells with human DNA also gave rise to 2 cisplatin-resistant clones, although it could not be ascertained if these clones were true transfectants or revertants. The survival of these resistant clones, after treatment with cisplatin, was about the same as WR cells a finding which would be consistent with complementation by a transferred gene or reversion of a single gene defect in WS cells. In their sensitivity only to difunctional compounds and lack of an apparent DNA excision repair defect the phenotype of Walker cells strongly resembles those cells from human patients suffering from Fanconi's anaemia and also of yeast snm1 mutant cells. The mechanisms giving rise to this failure to tolerate specific DNA damage (which seems to involve the inability to recover from the initial inhibition of DNA synthesis and may involve a single defect of a gene involved in the late steps of crosslink repair), do not involve drug uptake, drug binding to DNA, cell size, cell doubling time or DNA excision repair.

Animals↗
PubMed1992

The bioactivation of 5-(aziridin-1-yl)-2,4-dinitrobenzamide (CB1954)--II. A comparison of an Escherichia coli nitroreductase and Walker DT diaphorase.

A nitroreductase enzyme that has been isolated from Escherichia coli B is capable of bioactivating CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide] to a cytotoxic agent, a property shared with the mammalian enzyme Walker DT diaphorase [NAD(P)H dehydrogenase (quinone), EC 1.6.99.2] as isolated from Walker cells. In contrast to Walker DT diaphorase, which can only reduce the 4-nitro group of CB1954, the E. coli nitroreductase can reduce either (but not both) nitro groups of CB1954 to the corresponding hydroxylamino species. The two hydroxylamino species are formed in equal proportions and at the same rates. CB1954 is reduced much more rapidly by the E. coli nitroreductase than by Walker DT diaphorase. If the reduction of CB1954 was carried out in the presence of V79 cells (which are insensitive to CB1954) a large cytotoxic effect was evident. This cytotoxicity was only observed under conditions in which the E. coli nitroreductase or Walker DT diaphorase reduced the drug. It is proposed that E. coli B nitroreductase would be a suitable enzyme for antibody-directed enzyme prodrug therapy (ADEPT) in combination with CB1954.

Antibodies↗
PubMed1991

Head injury and the use of baby walkers: a continuing problem.

STUDY OBJECTIVE: To determine the frequency of baby walker use as a contributing factor in head injuries in children less than 2 years old. DESIGN: Retrospective clinical review. SETTING: Urban Level I trauma center and multispecialty clinic. TYPE OF PARTICIPANTS: All children less than 2 years old who were evaluated for a head injury during a three-year period. MEASUREMENTS AND MAIN RESULTS: 129 patients' cases were reviewed. Walker-related injuries occurred in 19 of 129 patients (14.7%). This represents the third most common mechanism of injury in this age group. Mean patient age at the time of injury was 8.7 months. Of the 19 accidents involving walkers, 18 (94.7%) involved falling down stairs. Nine children (47.4% of all walker-related injuries) suffered fractures of the cranial vault. No patients required surgical intervention, although one required treatment for post-traumatic meningitis. CONCLUSION: Baby walkers continue to be a frequent cause of head injury in this age group, and further efforts must be made to deal with these preventable injuries.

Accidental Falls↗
PubMed1991

Baby walker related injuries--a continuing problem.

Baby walkers have been associated with burns, head trauma and other types of injury. A retrospective study of all infants under the age of two years attending an accident and emergency unit demonstrated 22 injuries associated with baby walkers from a total of 1049 attendances. The most serious injuries were three skull fractures, with the most common mechanism being of a fall downstairs in the walker. Injury while in a baby walker occurred with a similar frequency to injury due to road traffic accidents. We conclude that despite previous warnings Baby Walkers still represent a considerable hazard to infants.

Accidents, Home↗
PubMed1975

Kinetics of cell proliferation and cell loss in the peripheral and central parts of Walker tumours growing in rats and nude mice.

In previous experiments it was shown that, in the submucosal part of Walker tumours transplanted to the gastric wall of rats, a lower rate of cell proliferation was seen in the peripheral zone, defined as the outer 100-120 mu of the tumours, than in the main tumour mass. The purpose of the present experiments was to investigate whether such differences are independent of the location of the Walker tumour, or were caused by local factors specific for the gastric mucosa, and whether specific cellular immunity cell proliferation at the periphery of a transplanted tumour. Cells from Walker 256 tumour were injected into the subcutaneous space in rats and in mutant nude mice, which lack T lymphocytes. In one series, the rats and mice were injected with 3H-TDR at different time intervals before sacrifice. In a second series vinblastine sulfate was injected 3 hours before sacrifice. Although all the animals were given the same tumour dose, the tumours in mice increased in size more slowly than those in rats. In the first-mentioned series, the mitotic counts, the labelled cells and the percentage labelled mitoses (PLM) in the main tumour mass and at the tumour perphery were counted. In the second series the mitotic rate in the same two regions was determined. A significantly lower rate of cell proliferation was demonstrated at the periphery compared to the main tumour mass in both rats and mice. Differences between the PLM curves in the two regions were also found. Possible explanations of these findings are discussed. It is concluded that the described growth pattern is probably a general characteristic of the Walker tumour, and that the low rate of proliferation at the periphery is not caused by specific immunological mechanisms mediated through T lymphocytes. If the growth rates were calculated on the assumtion that the actual tumour growth followed a Gompertz function, then the rate of cell loss in the tumour in mice was higher than that in the tumour in rats.

Animals↗
PubMed1992

Self-propelled weight-relieving walker for gait rehabilitation.

This paper describes a novel walking aid, the weight relieving walker (WRW), which partially relieves the body weight of an ambulating patient. The device incorporates a pneumatic weight relief mechanism, a restraint mechanism and a forward propulsion mechanism. Weight relief facilitates stance on an affected lower limb as well as the swing of that same limb. Restraint of the patient by the walker adds to trunk stability thereby facilitating walking movements of the lower extremities. A motorized, self-propelled walker neutralizes the effect of the walker's own weight on patient's locomotion. Additionally, it contributes to step symmetry. Data gathered from 26 patients with severe locomotion problems, point to a substantial contribution of the device to ambulation.

Adult↗
PubMed1991

Osteolytic activity of Walker carcinosarcoma 256 is due to parathyroid hormone-related protein (PTHrP).

The hypercalcemic Walker carcinosarcoma 256 of the rat is an animal model for humoral hypercalcemia of malignancy. Previous in vivo studies suggested the production of a parathyroid hormone-related protein (PTHrP) by the Walker tumor. Therefore, we have measured immunoreactive PTHrP in serum-free conditioned medium from cells derived from this tumor using an antibody raised against human PTHrP(1-34). Walker tumor cell conditioned medium (WCM) displaced 125I-hPTHrP(1-34) from the antibody in a dose dependent manner, whereas control medium contained no immunoreactive PTHrP. In contrast, we detected no secretion of immunoreactive rat parathyroid hormone (rat PTH) by the Walker tumor cells using a midregional radioimmunoassay for rat PTH. WCM stimulated adenylate cyclase in osteoblast like cells, the dose-response curve paralleling that of hPTHrP(1-34). This effect could be inhibited by the PTH antagonist (8Nle, 18Nle, 34Tyr)bPTH(3-34) and by the addition of anti-hPTHrP(1-34) antibody. Bone resorbing activity of WCM in organ culture (calvaria of fetal rats) was not inhibited by indomethacin and glucocorticoids, suggesting a prostaglandin independent mechanism of osteoclast activation in this model.

Adenylyl Cyclases↗
PubMed1990

Anterior versus posterior walkers: a gait analysis study.

Eight children, who needed walkers to ambulate and who were able to use either anterior or posterior walkers, were selected for a comparative study of both types of walker. Data for gait analysis, using high-speed cinematography, were collected to determine stride length, time in double support and velocity. Trunk, hip and knee angles were also measured during four phases of the gait cycle. The results demonstrated significant improvements in both postural alignment and gait characteristics with the posterior walker.

Cerebral Palsy↗
PubMed1992

Dandy-Walker variant: prenatal sonographic features and clinical outcome.

The Dandy-Walker variant is a less severe posterior fossa anomaly than the classic Dandy-Walker malformation. In 17 consecutive fetuses, the Dandy-Walker variant was diagnosed at sonography, and associated defects, karyotypic anomalies, and outcomes were evaluated. Four of the 17 fetuses (24%) had mild ventriculomegaly. Eight of the 17 (47%) had concurrent non-central nervous system (CNS) anomalies. Five fetuses (29%) had an abnormal karyotype (two with trisomy 18, one each with trisomy 13, 21, and 11q+) and associated sonographic anomalies. Six of the 17 fetuses (35%) died in utero or during the neonatal period, two are severely handicapped, and the other nine are developing normally at ages 4 months to 4 years. Six of the nine normally developing infants (53%) lacked non-CNS sonographic findings. Because the prognosis is uncertain for an infant born with the prenatal diagnosis of Dandy-Walker variant, prenatal recognition of the anomaly allows for the option of fetal karyotyping and for arrangement for postnatal follow-up.

Abnormalities, Multiple↗
PubMed1975

The Dandy-Walker and Arnold-Chiari malformations. Clinical, developmental, and teratological considerations.

Five patients with the Dandy-Walker syndrome had dysgenesis of the cerebellar vermis, cystic dilatation of the fourth ventricle, and a high position of the tentorium cerebelli. When only these features are present, the patient may lead a normal life. Additional defects usually account for the prominent clinical and pathological features of this syndrome. In this series, one patient had aqueductal stenosis, four had agenesis of the corpus callosum, two had hydrocephalus, one had cerebral abiotrophy, and one (a 72-year-old man) had no additional defects and no symptoms from his Dandy-Walker syndrome. An analysis of development and teratological considerations indicates that the Dandy-Walker and Arnold-Chiari malformations are complex disorders that have different causes and mechanisms and begin at different times in the emryonic period. The causes are still unknown.

Adolescent↗
PubMed1991

Flow cytometric measurement of cell cycle kinetics in rat Walker-256 carcinoma following in vivo and in vitro pulse labelling with bromodeoxyuridine.

Flow cytometric measurements of total DNA content, cell cycle distribution, and bromodeoxyuridine (BrdUrd) uptake were made in rat Walker-256 carcinoma cells. After both in vivo and in vitro pulse labelling with BrdUrd, Walker-256 tumor cells were stained with propidium iodide (PI) to estimate the total DNA content and a monoclonal antibody against BrdUrd to estimate the relative amount of cells in S phase. BrdUrd-labelled single cell suspensions were harvested at different time intervals to determine the movement of these cells within the cell cycle. To increase BrdUrd uptake, fluorodeoxyuridine (FDU), a thymidine antagonist, was also applied in vivo and in vitro. The results indicated exponential growth characteristics for this tumor between days 5 and 8 after implantation. Tumor doubling times, derived from changes in tumor volume in vivo and from the increase in cell number in vitro were similar. The mean time for DNA synthesis was estimated from the relative movement of BrdUrd-labelled cells towards G2. The percent of cells labelled with BrdUrd and the DNA synthesis time were similar regardless of the mode of BrdUrd administration. This study demonstrates that BrdUrd labelling of rat Walker-256 carcinoma cells in vitro yields kinetic estimates of tumor proliferation during exponential growth similar to those with the administration of BrdUrd in the intact tumor-bearing rat.

Animals↗
PubMed1979

Aggregation of activated platelets with Walker 256 carcinoma cells.

Walker 256 carcinoma cells form irreversible aggregates with rat platelets activated by ADP or serotonin. Since serotonin induces platelet shape change but not platelet aggregation the degree of activation indicated by the disc-sphere transformation is sufficient for platelets to interact with these tumor cells. This is confirmed by experiments with spheroid washed platelets which form irreversible mixed aggregates with Walker 256 carcinoma cells without a stimulus being required. This type of tumor cells could react with platelets in vivo, provided the platelets are activated by disturbed blood flow or contact with subendothelium. Our observations can explain why other authors found no interaction between Walker 256 carcinoma cells and non-activated platelets in vitro even though platelets contributed to the formation of bloodborne metastases of this tumor.

Adenosine Diphosphate↗