Biomedical subjects

D Walton

Publications and source records attributed to D Walton.

8 recordsLinked to original sources

PubMed1991

Chiropractic care of children with nocturnal enuresis: a prospective outcome study.

Functional nocturnal enuresis is a common problem which causes a great deal of stress to the suffering children and their families. Some chiropractors advocate chiropractic care as a mode of therapy for this complaint. One hundred and seventy-one enuretic children, aged 4 to 15, were treated with chiropractic adjustments, and their number of wet nights was monitored by their parents. The median number of wet nights per week was 7.0 at the onset of the study. After 2 wk without any therapy, the number of wet nights had decreased to 5.6 (p = .01) and by the end of the treatment this figure was 4.0 (p less than .0001). Following the course of treatment, 15.5% of subjects wet a maximum of 2 nights per fortnight, or, where data for the last 2 wk of therapy were unavailable, a maximum of 1 night/wk. This result is less favorable than the therapeutic success of other common types of therapy, which have reported "cure" rates well above 50%. The only variable which predicted treatment outcome was the initial estimate of bed-wetting; the more severe the condition at the onset, the less likely was the child to improve by the end of the study. In the absence of a control group there appears to be no validity in the claim that chiropractic is a treatment of choice for functional nocturnal enuresis.

Adolescent↗

PubMed1990

Ligneous conjunctivitis with ear involvement.

We report the association of ligneous conjunctivitis with middle-ear and tympanic membrane involvement in two children. Eye and ear specimens revealed histopathologic and ultrastructural findings consistent with ligneous conjunctivitis, characterized by an amorphous, eosinophilic material with acute and chronic nongranulomatous inflammation. Ear specimens demonstrated granulation tissue along with the above features. Conjunctival and ear lesions from these patients were studied histochemically, immunohistochemically, and ultrastructurally. Our studies demonstrate fibrin and albumin deposition as a common feature in all lesions. Deposition of other components, such as mucopolysaccharides, amyloid, immunoglobulins, and mast cells, were, however, variable. The diversified nature of these lesions, together with the association of eye and ear disease, substantiates the existence of an underlying systemic disorder of unknown cause.

Amyloid↗

PubMed1990

Characterization of cerebral energetics and brain pH by 31P spectroscopy after graded canine cardiac arrest and bypass reperfusion.

Recovery of cerebral energy metabolism is used to indicate CNS viability after ischemia. This study utilized 31P nuclear magnetic resonance (NMR) spectroscopy to measure cerebral energy state and intracellular pH in dogs subjected to 8, 12, or 16 min of cardiac arrest and reperfusion using cardiopulmonary bypass. Spectra were obtained throughout ischemia and initial reperfusion and repeated at 30 and 144 h post ischemia. Neurologic deficit scoring was performed at 12 and 24 h post insult and then daily. High-energy phosphates were depleted by the end of all ischemic intervals. Recovery occurred within 60 min of reperfusion and persisted with no differences in the rate of return between groups (p greater than 0.05). Brain pH (pHb) decreased by the end of ischemia in all groups (p less than 0.0001). Neither the pHb nadir nor its recovery differed between groups (p greater than 0.05). Although longterm neurologic outcome differed between groups, the spectra were similar. Assessment of cerebral energy state using 31P NMR spectroscopy does not appear to be a sensitive indicator of neurologic outcome after global ischemia in dogs. Return of high-energy phosphates may be a necessary but not sufficient condition for cerebral recovery after ischemia. The return of high-energy phosphates after a 16-min cardiac arrest, however, indicates a potential for neurological recovery.

Acid-Base Equilibrium↗

PubMed1989

Oncogenic point mutations in the human retinoblastoma gene: their application to genetic counseling.

Mutations of the retinoblastoma gene, most of which cannot be detected by conventional Southern blotting, are known to cause both the nonhereditary and hereditary forms of retinoblastoma and have been implicated in the development of other cancers. Nonhereditary retinoblastoma is caused by a somatic mutation. Hereditary retinoblastoma is caused by a germ-cell mutation, most often a new one, and thus there is usually no family history of the disease. Unlike patients with the nonhereditary disease, those with the hereditary form are at risk for additional retinoblastomas, and their progeny are at risk for the tumors. We used a sensitive technique of primer-directed enzymatic amplification, followed by DNA sequence analysis, to identify mutations as small as a single nucleotide change in tumors from seven patients with simplex retinoblastoma (with no family history of the disease). In four patients the mutation involved only the tumor cells, and in three it involved normal somatic cells as well as tumor cells but was not found in either parent; thus, these mutations appeared to be new, germ-cell mutations. In addition, we found point mutations in cells from a bladder carcinoma, a small-cell carcinoma of the lung, and another retinoblastoma. We conclude that the technique that we have described can distinguish hereditary from nonhereditary retinoblastoma and that it is useful in risk estimation and genetic counseling.

Base Sequence↗

PubMed1989

Parental origin of mutations of the retinoblastoma gene.

Retinoblastoma and osteosarcoma arise from cells that have lost both functional copies of the retinoblastoma gene. Using the cloned retinoblastoma gene and other linked polymorphic loci, it is possible to reconstruct the sequential loss of the two homologous gene copies that precedes the development of these tumours. In non-hereditary tumours, the loss of each of the two homologues occurs somatically; in hereditary cases, the initial mutation is in the germline. Recently, Toguchida et al. reported that the paternally derived copy is preferentially the first one to become mutant during the genesis of non-hereditary osteosarcomas. We report here a similar analysis of patients with retinoblastoma in which we find no such predilection for initial somatic mutations. In contrast, when an initial mutation was a new germline mutation, it was derived from the father, a result which is consistent with new germline mutations arising primarily during spermatogenesis.

Adult↗

PubMed1989

The effect of CO2 and non-CO2-generating buffers on cerebral acidosis after cardiac arrest: A 31P NMR study.

There is controversy regarding the use of alkalinizing agents during reperfusion after cardiac arrest. The potential deleterious effects of sodium bicarbonate (bicarb) administration, including paradoxic cerebral acidosis, have led to the search for alternative agents. Tromethamine (tris) is a non-CO2-generating buffer that has been proposed for use during cardiopulmonary resuscitation. The purpose of this experiment was to compare the ability of tris with bicarb to correct brain pH (pH B) during reperfusion after a 12-minute cardiac arrest. Adult mongrel dogs were instrumented and placed in the bore of a Bruker Biospec 1.89 tesla superconducting magnet system. Ventricular fibrillation was induced; after 12 minutes, cardiopulmonary bypass was initiated and maintained for two hours with minimum flows of 80 mL/kg/min. Bicarb (n = 5) or tris (n = 5) were administered to correct arterial pH as rapidly as possible. 31P NMR spectra were obtained at baseline and throughout ischemia and reperfusion. The pH B was determined with the inorganic phosphate relative to the phosphocreatine resonance signal shift. Profile analysis indicates a difference between groups (P less than .02) related to an initial delay in pH B correction in the tris group. By 48 minutes of reperfusion, pH B did not differ between the groups. Moreover, there was no evidence of paradoxic cerebral acidosis in the bicarb group. Although tris corrects blood pH as quickly as bicarb, it is less effective in correcting pH B. Absence of paradoxic acidosis may be caused by efficient elimination of CO2 by cardiopulmonary bypass.

Acidosis↗

PubMed1979

RNase levels in golden hamster with DHPN induced pancreatic cancer.

Twenty Syrian golden hamsters recieved weekly injections of pancreatic cancer inducing DHPN. Their Poly (U) specific serum RNase levels were significantly elevated when compared to the control levels. Following salt fractionation, Poly (U) specific activity was present in both the 40% and 50% salt saturated fractions. Tissue assays showed that Poly (U) specific RNase was present in both pancreas and liver tissue extract, although the liver tissue RNase had a different pH maximum than that of the serum RNase.

Adenocarcinoma↗

PubMed1978

Size and shape of the model lipoprotein complex formed between glucagon and dimyristoylglycerophosphocholine.

Glucagon forms water-soluble lipoprotein particles with dimyristoylglycerophosphocholine at temperatures below the phase-transition temperature of the lipid. The shape and size of this lipoprotein particle were studied by viscometry, sedimentation velocity, sedimentation equilibrium, quasielastic light scattering, and electron microscopy using both negative-staining and freeze-fracture techniques. The lipoprotein particle has an oblate ellipsoid shape with dimensions of 250 X 70 A and an approximate molecular weight of 1.4 X 106. This molecular weight is similar to that found for small unilamellar phospholipid vesicles but is achieved in the presence of glucagon without sonication. The shape of the glucagon lipoprotein particle is similar to that found for the complex formed between some serum apolipoproteins and dimyristoylglycerophosphocholine. From these data, a model for the glucagon-dimyristoylglycerophosphocholine is proposed consisting of a single bilayer of phospholipid with the glucagon incorporated into the bilayer structure in such a manner as not greatly to disturb the average area occupied per phospholipid molecule.

Glucagon↗