A randomized, cross-over trial comparing the effect of innovative robotic gait training and functional clinical therapy in children with cerebral palsy; a protocol to test feasibility

PURPOSE

Robotic gait training is relatively new in the world of pediatric rehabilitation. Preliminary feasibility studies and case reports include stationary robot-assisted treadmill training. Mobile robotic gait trainers hold greater promise for intensive practice-based therapy within hospitals, schools, rehabilitation centers, and at-home therapy as they enable participation and social integration while practicing high-quality gait patterns.

MATERIALS AND METHODS

This paper (clinical trials registry number: NCT05378243) provides a detailed description of a mixed-method cross-over trial design with a broad set of outcome measures. Ultimately the goal is to establish the feasibility of this design which includes the collection of qualitative data regarding patient, family, and therapist experience and quantitative data regarding gait efficiency and quality, impact on tone, individualized goal achievement and bone strength.

Development and evaluation of a protocol to manage fecal incontinence in the patient with cancer

Fecal incontinence is an important yet often overlooked clinical problem in the care of patients with cancer. This paper presents a protocol for the assessment and management of this distressing symptom. The objective of the protocol is to regulate bowel motion, thereby minimizing fecal incontinence and improving patients' physical functioning, self-esteem, dignity, and quality of life. A comprehensive assessment addressing the patient's physical status, previous elimination routines, dietary habits, and medications provides the foundation for successful management. Components of the intervention include dietary modification, pharmacotherapy with laxatives and suppositories, and attention to routines that capitalize on the normal, involuntary gastrointestinal reflexes. Promotion of normal bowel elimination patterns, positioning, and comprehensive patient teaching and support are also critical components of the intervention. Our experience with this protocol and the outcomes achieved in a small series of patients are discussed.

Temporal distribution of retinoic acid and cellular retinoic acid-binding protein (CRABP) in the fetal hamster

The temporal relationship between the distribution of retinoic acid, a known human and rodent teratogen, and that of cellular retinoic acid-binding protein (CRABP) was investigated from Day 11 to Day 14 of hamster prenatal development. The 11,12-(3)H2 and 15(-14C) forms of all-trans-retinoic acid were used for quantitative distribution studies and autoradiography, respectively, and were evaluated 15 min after a single intravenous injection. Radioactivity was detected in all fetal tissues examined (brain, liver, heart, spinal cord, limb, and skin), and at Day 14, approximately 66% of the total radioactivity was present as parent all-trans-retinoic acid. High concentrations of total radioactivity were observed by autoradiography in the midbrain and hindbrain (mesencephalon, metencephalon, and myelencephalon) and spinal cord, but not in the forebrain. At the earliest time studied, limb buds showed relatively high concentrations of radioactivity. Levels of radioactivity were also high in portions of the developing face, nose, and tongue. Immunohistochemical analyses indicated that the amount of CRABP in Day 14 tissues was the highest in spinal cord followed by limb and skin; heart and liver contained only relatively small amounts of this protein. From Day 11 to Day 14, the amount of CRABP, as measured by high-performance size-exclusion liquid chromatography, in the whole body decreased as gestation progressed. Microscopic immunohistochemical localization of CRABP found the highest concentration in the ventral midbrain and in the ventral and lateral sides of the hindbrain and spinal cord; CRABP was also abundant in tongue, limb, and skin. The distribution of CRABP-positive cells in the central nervous system was similar to the distribution of retinoic acid. The data presented here indicate that fetal CRABP appears to play a role in differential accumulation of retinoic acid in certain structures of the developing hamster. The patterns of tissue retinoid and CRABP distribution observed here are consistent with the patterns of congenital malformations induced by prenatal retinoid exposure.

Cellular retinoic acid binding protein: detection and quantitation in regenerating axolotl limbs

The concentrations of apo (unoccupied), holo (occupied), and total cellular retinoic acid binding protein (CRABP) were measured at various stages of axolotl limb regeneration. The ratio of apo-CRABP to holo-CRABP declined with advancing regenerate stage until the CRABP was all in the holo form. The increase in holo-CRABP is correlated with a stage-dependent shift in the effect of exogenous retinoic acid on regenerate pattern, from pattern duplication to inhibition of regeneration. The data suggest, though they do not prove, that these different morphological effects could be due to a shift from a CRABP-dependent to a CRABP-independent mechanism of exogenous retinoic acid (RA) action that is related to stage-specific variations in endogenous RA levels.

Molecular cloning and analysis of functional cDNA and genomic clones encoding bovine cellular retinoic acid-binding protein

A recombinant cDNA clone, pCRABP-HS1, encoding cellular retinoic acid-binding protein was isolated from a bovine adrenal cDNA library. COS-7 cells transfected with pCRABP-HS1 produced a biologically active retinoic acid-binding protein molecule of the expected molecular mass (15.5 kDa). RNA blot hybridization analysis using pCRABP-HS1 as a probe revealed a single 1050-nucleotide mRNA species in bovine adrenal, uterus, and testis, tissues that contain the highest levels of retinoic acid-binding activity. No hybridization was detected in RNA extracted from ovary, spleen, kidney, or liver, which contain relatively low levels of cellular retinoic acid-binding protein activity. Analysis of genomic clones isolated from an EcoRI bovine genomic library demonstrated that the bovine cellular retinoic acid-binding protein gene is composed of four exons and three introns. Two putative promoter sequences were identified in the cloned 5' sequence of the gene.

Determination of apo and holo retinoic acid-binding protein levels in retinoid-responsive transformed cells by high-performance size-exclusion chromatography

A method to measure the endogenous levels of apo and holo cellular retinoic acid-binding proteins was developed using calf testis cytosol as the source of retinoic acid-binding protein. [3H]Retinoic acid-retinoic acid-binding protein complexes were assayed by high-performance size-exclusion chromatography. Preincubation of cytosol with 10 mM p-hydroxymercuribenzoate at 4 degrees C resulted in complete inhibition of retinoic acid binding to apo retinoic acid-binding protein. In addition, total dissociation of preformed holo retinoic acid-binding protein complexes was noted within 20 min after mercurial addition. Thus, p-hydroxymercuribenzoate converted the total pool of cellular retinoic acid-binding protein (apo plus holo) to mercurial-protein complexes unable to bind retinoic acid in vitro. Mercurial inhibition of retinoic acid-retinoic acid-binding protein complex formation was totally reversed upon the addition of 50 mM dithiothreitol. Total cytosolic retinoic acid-binding protein was determined from specific retinoic acid binding after treatment with p-hydroxymercuribenzoate and dithiothreitol. Apo cellular retinoic acid-binding protein concentration was measured by determining specific radioligand binding prior to p-hydroxymercuribenzoate treatment, and correcting for exchange of endogenously bound retinoid with exogenous tritiated retinoic acid. Holo cellular retinoic acid-binding protein concentration was derived from the difference between total and apo retinoic acid-binding protein concentrations. Using this method, we have demonstrated that retinoid-responsive EJ and T24 human bladder carcinoma cell lines and AT3A and AT3B rat pancreatic acinar carcinoma cell lines lack detectable levels of either apo or holo cellular retinoic acid-binding protein. These results established that retinoid inhibition of transformed bladder and acinar cell proliferation in culture was mediated by a cellular retinoic acid-binding protein-independent mechanism.

Specific, covalent binding of an azidoretinoid to cellular retinoic acid-binding protein

Two C(5)-azido substituted aromatic retinoids were evaluated as photoaffinity probes for studying the mechanism of retinoid action. The secondary azide 1 and the tertiary azide 2 were equipotent with the parent C(5)-geminal-dimethyl substituted aromatic retinoid 3 in stimulating F9-cell differentiation. Both azides bound covalently to cellular retinoic acid-binding protein upon photolysis, but the secondary azide was twice as efficient, likely because of lesser steric hindrance. The covalent binding of azide 1 was specific, since it was inhibited by retinoic acid. Thus substitution of a photolabile group onto aromatic retinoids does not abolish biological activity and affinity for cellular retinoic acid-binding protein.

Vitamin A metabolism: alpha-tocopherol modulates tissue retinol levels in vivo, and retinyl palmitate hydrolysis in vitro

The steady-state concentrations of retinol in rat tissues varied as a function of dietary alpha-tocopherol. The liver, kidney, and intestinal retinol concentrations increased in animals fed an alpha-tocopherol-deficient diet despite a decrease (liver) or no change (kidney and intestine) in the concentrations of total vitamin A. In contrast, in lung the concentrations of both retinol and total vitamin A decreased. alpha-Tocopherol inhibited retinyl palmitate hydrolase in vitro in liver, kidney, and intestine; had minimal effect on the testes hydrolase; and stimulated the lung hydrolase. Fifty percent inhibition of the liver hydrolase was provided by an alpha-tocopherol concentration (100 microM), close to that reported in livers of rats fed a purified diet, constituted with moderately low amounts of alpha-tocopheryl acetate. Phylloquinone (vitamin K1) inhibited the retinyl palmitate hydrolase in vitro in all tissues tested, and was about fivefold more potent than alpha-tocopherol. The effects of phylloquinone and alpha-tocopherol on the liver hydrolase were additive, not synergistic. The antioxidant N,N'-diphenyl-p-phenylenediamine, the most effective synthetic vitamin E substitute known, had little effect on the hydrolase. These data show that alpha-tocopherol effects vitamin A metabolism in several tissues, and suggest that it may be a physiological effector of tissue retinol homeostasis.

Rapid characterization of cellular retinoid-binding proteins by high-performance size-exclusion chromatography

A high-performance size-exclusion chromatographic method was developed for the analysis of cellular retinol and retinoic acid-binding proteins. The chromatographic analysis of the retinol-retinol-binding protein complex or the retinoic acid-retinoic acid-binding protein complex requires 15 min. The use of high-specific-radioactivity retinoid ligand (30-40 Ci/mmol) allows routine detection of 25 fmol of retinoid-binding protein/mg of cytosolic protein. Thus, this method provides a rapid alternative to sucrose density gradient sedimentation analysis of the cellular retinoid-binding proteins. High-performance size-exclusion chromatography is well suited to screening novel tissues, tumors, and cell lines for the presence of retinoid-binding proteins and to the further characterization of these cellular proteins. This method was applied to the characterization of cellular retinol- and retinoic acid-binding proteins in fetal rabbit tissues. Both retinol- and retinoic acid-binding proteins were detected in fetal rabbit brain, intestine, kidney, and lung at a gestational age of 28 days. Neither retinoid-binding protein was detected in 28-day-old fetal rabbit placenta. Specific retinoic acid binding in fetal intestinal cytosol decreased as a function of increasing gestational age.

13-cis-retinoic acid metabolism in vivo. The major tissue metabolites in the rat have the all-trans configuration

The liver and intestinal metabolites of orally dosed 13-cis-[11-3H]retinoic acid were analyzed in normal and 13-cis-retinoic acid treated rats 3 h after administration of the radiolabeled retinoid. all-trans-Retinoic acid was identified as a liver and intestinal mucosa metabolite in normal rats given physiological doses of 13-cis-[3H]retinoic acid. all-trans-Retinoyl glucuronide was identified as the most abundant radiolabeled metabolite in mucosa and a prominent liver metabolite under the same conditions. Thus, the major 13-cis-retinoic acid metabolites retained in liver and mucosa, two retinoid target tissues, had the all-trans configuration. These data indicate that the isomerization of 13-cis-retinoic acid to all-trans-retinoic acid and the subsequent conversion to all-trans-retinoyl glucuronide are central events in the in vivo metabolism of 13-cis-retinoic acid in the rat. Moreover, the all-trans-retinoic acid detected in vivo could account for a significant fraction of the physiological activity of 13-cis-retinoic acid. The tissue disposition and metabolism of orally dosed 13-cis-[3H]retinoic acid are modulated by retinoid treatment. Chronic 13-cis-retinoic acid treatment apparently increased the intestinal accumulation of all-trans-retinoic acid, all-trans-retinoyl glucuronide, and 13-cis-retinoyl glucuronide. The liver concentrations of tritiated all-trans-retinoic acid and all-trans-retinoyl glucuronide were also elevated in 13-cis-retinoic acid treated rats.

Metabolism of 5,6-epoxyretinoic acid in vivo: isolation of a major intestinal metabolite

The major metabolite in the small intestinal mucosa of vitamin A deficient rats dosed intrajugularly with 5,6-epoxy[3H]-retinoic acid has been identified as 5,6-epoxyretinoyl beta-glucuronide. The assignment was based on the metabolite's chemical, spectral, and chromatographic properties. Incubation of the metabolite with beta-glucuronidase released 5,6-epoxyretinoic acid. Incubation of 5,6-epoxyretinoic acid with rat liver microsomes in the presence of uridine-5'-diphospho-1 alpha-D-glucuronic acid produced the metabolite. 5,6-Epoxy[3H]retinoyl beta-glucuronide weas observed in the liver, small intestinal mucosa, and intestinal contents but not in kidney of vitamin a deficient rats. Its concentration was greatly diminished in liver and small intestinal mucosa, and it was not observed in kidney of vitamin A deficient rats dosed orally with retinoic acid for several days before administration of 5,6-epoxy[3H]retinoic acid. Generally, oral retinoic acid treatment accelerated 5,6-epoxyretinoic acid metabolism and enhanced accumulation of highly polar metabolites. Moreover, 5,6-epoxyretinoic acid metabolism was more rapid than that of retinoic acid and did not result in production of retinoic acid.

Identification of 5,6-epoxyretinoic acid as an endogenous retinol metabolite

Rats on a normal diet were administered physiological doses of [3H]retinyl acetate or [3H]retinol orally for 5 days to label endogenous retinoid pools. The kidney retinoids were extracted and separated by DEAE-Sephadex into neutral and acidic fractions. All-trans-retinoic acid and 5,6-epoxyretinoic acid were isolated and unequivocally identified by chromatographic analysis, chemical derivatization, and mass spectroscopy. The identities of retinol and retinyl palmitate were verified by high performance liquid chromatography and reactivity with trifluoroacetic acid. Control experiments showed that retinoid epoxidation truly occurred in vivo. The specific radioactivities of the recovered acidic retinol metabolites were similar to those of the recovered neutral retinoids. Thus, retinoic acid and its metabolite 5,6-epoxyretinoic acid are endogenous rat kidney retinoids which are in the pathway of retinol metabolism under physiological conditions. The concentrations of retinyl palmitate (8.7 microM), retinol (4.6 microM), all trans-retinoic acid (1.3 microM) and 5,6-epoxyretinoic acid (0.25 microM) measured indicate that acidic retinoids are comparatively significant vitamin A metabolites in kidney.

Tissue dependence of retinoic acid metabolism in vivo

Metabolites formed in vivo from [3H]retinoic acid dosed intrajugularly to vitamin A-deficient rats and to vitamin A-deficient rats supplemented orally with unlabeled retinoic acid were investigated. Extracts of liver, small intestinal mucosa, kidney, testes and serum were separated into charged uncharged fractions by DEAE-Sephadex. This allowed the direct application of 20-40% of the combined charged extracts from up to six organs to be loaded onto a high-performance liquid chromatography column. The large aliquot size plus the use of relatively high specific activity [3H]retinoic acid resulted in detection of nanomolar metabolite quantities. The substantial resolution achieved with the high-performance liquid chromatography gradient system aided in demonstrating the complexity, extent and variations of retinoic acid metabolism in vivo, The metabolic profiles changed with retinoic acid pretreatment, time after dose and tissue source. Some 3H-labeled metabolites were predominant in vitamin A-deficient animals; others appeared to be predominant in the retinoic acid-supplemented animals. The gross effect of retinoic acid supplementation was to both accelerate retinoic acid metabolism and cause an accumulation of more polar metabolites. It appears that retinoic acid metabolism in vivo is a complex process that occurs through multiple metabolites, which are, at least partially, tissue-specific.

5,6-epoxyretinoic acid is a physiological metabolite of retinoic acid in the rat

5,6-Epoxyretinoic acid was detected in small intestine, kidney, liver, testes and serum of vitamin A-deficient rats 3 h after a single physiological dose of [3H]retinoic acid. The maximum concentration of 5,6-epoxide in intestinal mucosa was observed 3 h after intrajugular administration of retinoic acid. However, at 7 h post administration, no 5,6-epoxyretinoic acid was detected in mucosa, demonstrating the rapid intestinal metabolism or excretion of this metabolite. No 5,6-epoxy[3H]retinoic acid was detected in mucosa, liver or serum of retinoic acid-repleted rats 3 h after administration of 2 micrograms of [3H]retinoic acid.

Isolation and identification of 5, 6-epoxyretinoic acid: a biologically active metabolite of retinoic acid

A highly biologically active metabolite of retinoic acid (8III) has been isolated in pure form from intestinal mucosa of vitamin A deficient rats given [3H]retinoic acid. This metabolite has been positively identified as 5, 6-epoxyretinoic acid based on the ultraviolet absorption spectrum and mass spectrum of its methylated derivative. This identification was confirmed by cochromatography of the methylated metabolite and synthetic methyl 5, 6-epoxyretinoate on reverse-phase and straight-phase high-pressure liquid chromatography. The 5, 6-epoxyretinoic acid is a true in vivo generated metabolite of retinoic acid and not an artifact of the isolation procedure. In addition, 5, 8-oxyretinoic acid previously isolated in this laboratory from intestinal mucosa was probably generated from 5, 6-epoxyretinoic acid by the acidic conditions used in the extraction and isolation of the 5, 8-oxyretinoic acid.

Identification of 5,8-oxyretinoic acid isolated from small intestine of vitamin A-deficient rats dosed with retinoic acid

A retinoid was isolated by a multistep procedure from the small intestines of vitamin A-deficient rats given a single dose of retinoic acid. The compound, designated 8II, was pure, as demonstrated by four high-pressure liquid chromatographic procedures. It was positively identified as 5,8-oxyretinoic acid by ultraviolet spectrophotometry, mass spectrometry, and spectral and chromatographic comparison to known compounds. It is probable that 5,8-oxyretinoic acid was produced from 5,6-epoxyretinoic acid under the acidic conditions used in the isolation. It is highly probable, therefore, that the natural product is 5,6-epoxyretinoic acid.

The effect of vitamin A deficiency on testicular transfer RNA methyltransferase activity

Testicular transfer RNA methyltransferase activity was examined in normal and vitamin A-deficient rats. The specific activity was reduced by 50% in the vitamin A-deficient rats. In addition, a 5-fold decrease in the extent of tRNA methylation was observed with enzyme preparations from deficient testes. Both the rate and extent of tRNA methylation returned to control levels in vitamin A-repleted rats. In contrast, retinoic acid repletion did not reverse the effect of vitamin A deficiency on testicular tRNA methyltransferase activity. The methylated nucleoside composition of tRNA methylated by extracts of vitamin A-deficient testes was altered dramatically compared to that of tRNA methylated by control testicular enzymes. Decreased testicular tRNA methyltransferase activity was noted in midly deficient rats before the onset of testicular degeneration suggesting that the decreased tRNA methyltransferase activity in the testes is primarily the result of vitamin A deficiency.

The effect of retinol and retinoic acid on physiological and biochemical changes in retinol-deficient rats

1. The effects of retinol and retinoic acid supplementation of retinol-deficient rats were studied for a variety of metabolic processes shown to be affected by retinol-deficiency. 2. Retinol-deficient rats were found to have decreased body-weight, liver and testes weights, a degeneration of testicular germinal cells, an increased incorporation of labelled choline into liver and testes phospholipids, an increased protein synthetic activity (in vitro) of liver ribosomes, an increased transfer-RNA methyltransferase activity in liver and a decreased activity in testes, an increased DNA content of testicular nuclei, and a decreased uptake of [3-H]thymidine by testicular nuclear DNA. 3. In retinol-deficient rats supplemented for 8 weeks with retinol these changes were reversed, measurements returning to control levels. 4. In retinol-deficient rats supplemented for 8 weeks with retinoic acid all changes were reversed except those in the testes. 5. Testicular signs of retinol deficiency appeared to be delayed when retinoic acid was added to the retinol-deficient diet of weanling rats. This suggests a sparing action of retinoic acid on the rat's utilization of retinol. 6. Suggestions are offered as to why retinoic acid will support growth and development but not spermatogenesis in the rat.