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Biomedical subjects

C Sheldon

Publications and source records attributed to C Sheldon.

16 recordsLinked to original sources
PubMed2001

Treatment demands and differential treatment of patients with cystic fibrosis and their siblings: patient, parent and sibling accounts.

Cystic fibrosis (CF) is a progressive disease with no known cure. Advances in diagnosis and treatment have resulted in patients living longer and thus families live with the illness for longer. Treatments are becoming increasingly demanding and are largely performed in the family home. Mothers are often reported to experience greater stress and poorer adjustment than mothers of well children or population norms. Patients and siblings are also reported to display adjustment difficulties. Siblings have rarely been included in research designs. This qualitative study investigates the impact of CF and treatment on eight patients, eight mothers, one father and eight siblings. A family systems perspective was adopted. Each individual was interviewed independently using semistructured interviews. Patients and siblings were aged between 9 and 21 years. Qualitative analyses revealed high levels of non-adherence (intentional and unintentional) and parental involvement in treatment, minimal involvement of siblings, and preferential treatment towards patients. Demanding treatment, coupled with the progressive nature of CF, promote high levels of parental involvement for younger children as well as older teenagers, often due to attempted or actual non-adherence. Siblings may receive less attention while patients' needs take priority. Future development of a measure of adherence suitable for children and adolescents should take into account different motivations for non-adherence, particularly regarding the level of personal control over adherence to treatment. In addition, the potential impact of having a brother or sister with CF should not be underestimated and the needs of siblings should not go unnoticed.

Adaptation, Psychological↗
PubMed2001

In situ calibration and [H+] sensitivity of the fluorescent Na+ indicator SBFI.

Despite the popularity of Na+-binding benzofuran isophthalate (SBFI) to measure intracellular free Na+ concentrations ([Na+](i)), the in situ calibration techniques described to date do not favor the straightforward determination of all of the constants required by the standard equation (Grynkiewicz G, Poenie M, and Tsien RY. J Biol Chem 260: 3440-3450, 1985) to convert the ratiometric signal into [Na+]. We describe a simple method in which SBFI ratio values obtained during a "full" in situ calibration are fit by a three-parameter hyperbolic equation; the apparent dissociation constant (K(d)) of SBFI for Na+ can then be resolved by means of a three-parameter hyperbolic decay equation. We also developed and tested a "one-point" technique for calibrating SBFI ratios in which the ratio value obtained in a neuron at the end of an experiment during exposure to gramicidin D and 10 mM Na+ is used as a normalization factor for ratios obtained during the experiment; each normalized ratio is converted to [Na+](i) using a modification of the standard equation and parameters obtained from a full calibration. Finally, we extended the characterization of the pH dependence of SBFI in situ. Although the K(d) of SBFI for Na+ was relatively insensitive to changes in pH in the range 6.8-7.8, acidification resulted in an apparent decrease, and alkalinization in an apparent increase, in [Na+](i) values. The magnitudes of the apparent changes in [Na+](i) varied with absolute [Na+](i), and a method was developed for correcting [Na+](i) values measured with SBFI for changes in intracellular pH.

Animals↗
PubMed1999

Anoxia-evoked intracellular pH and Ca2+ concentration changes in cultured postnatal rat hippocampal neurons.

The ratiometric indicators 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein and Fura-2 were employed to examine, respectively, intracellular pH (pHi) and calcium ([Ca2+]i) changes evoked by anoxia in cultured postnatal rat hippocampal neurons at 37 degrees C. Under both HCO3-/CO2- and HEPES-buffered conditions, 3-, 5- or 10-min anoxia induced a triphasic change in pHi consisting of an initial fall in pHi, a subsequent rise in pHi in the continued absence of O2 and, finally, a further rise in pHi upon the return to normoxia, which recovered towards preanoxic steady-state pHi values if the duration of the anoxic insult was < or = 5 min. In parallel experiments performed on sister cultures, anoxia of 3, 5 or 10 min duration evoked rises in [Ca2+]i which, in all cases, commenced after the start of the fall in pHi, reached a peak at or just following the return to normoxia and then declined towards preanoxic resting levels. Removal of external Ca2+ markedly attenuated increases in [Ca2+]i, but failed to affect the pHi changes evoked by 5 min anoxia. The latency from the start of anoxia to the start of the increase in pHi observed during anoxia was increased by perfusion with media containing either 2 mM Na+, 20 mM glucose or 1 microM tetrodotoxin. Because each of these manoeuvres is known to delay the onset and/or attenuate the magnitude of anoxic depolarization, the results suggest that the rise in pHi observed during anoxia may be consequent upon membrane depolarization. This possibility was also suggested by the findings that Zn2+ and Cd2+, known blockers of voltage-dependent proton conductances, reduced the magnitude of the rise in pHi observed during anoxia. Under HCO3-/CO2-free conditions, reduction of external Na+ by substitution with N-methyl-D-glucamine (but not Li+) attenuated the magnitude of the postanoxic alkalinization, suggesting that increased Na+/H+ exchange activity contributes to the postanoxic rise in pHi. In support, rates of pHi recovery from internal acid loads imposed following anoxia were increased compared to control values established prior to anoxia in the same neurons. In contrast, rates of pHi recovery from acid loads imposed during anoxia were reduced, suggesting the possibility that Na+/H+ exchange is inhibited during anoxia. We conclude that the steady-state pHi response of cultured rat hippocampal neurons to transient anoxia is independent of changes in [Ca2+]i and is characterized by three phases which are determined, at least in part, by alterations in Na+/H- exchange activity and, possibly, by a proton conductance which is activated during membrane depolarization.

Animals↗
PubMed1995

The use of pramipexole, a novel dopamine (DA) agonist, in advanced Parkinson's disease.

We evaluated the efficacy, safety and tolerability of a new dopamine D-2 receptor agonist, pramipexole [(S)-2-amino-4,5,6,7-tetrahydro-6-propylamino-benzathiazol-dihydro chloride], as adjunctive therapy in patients with advanced Parkinson's disease (PD). Twenty-four PD patients with motor fluctuations were treated in an 11 week prospective, single-blind parallel-group, placebo-controlled trial. The pramipexole treated group experienced a significant improvement in "off" time functioning as measured by the activities of daily living portion of the United Parkinson's Disease Rating Scale. In addition, the active treatment group was able to reduce total levodopa dose by 30% (p < 0.05). Pramipexole was well tolerated and the side effects reported were typical of other dopamine agonists. We conclude that pramipexole has antiparkinsonian effects which make it potentially useful in the treatment of motor fluctuations in PD.

Aged↗
PubMed1994

Complete nonunion of the ureterovesical junction with preservation of renal function.

We report on a neonate with a history of failure to thrive who had a large right abdominal mass. Renal ultrasound showed a large cystic mass that arose from the upper pole of the hydronephrotic right kidney. Preoperative antegrade pyelography confirmed that the mass communicated with 1 kidney. Further evaluation revealed no communication of the ureter with the bladder or vagina. Exploratory surgery identified the mass and intraoperative pyelography revealed no communication with the bladder. After resection of the mass and nephrostomy placement, reimplantation of the right ureter demonstrated complete atresia of the distal right ureter. Preservation of the remaining renal parenchyma was possible, because the functioning lower pole collecting system communicated with the cystic mass that arose from the upper pole.

Female↗
PubMed1993

Early combination therapy (bromocriptine and levodopa) does not prevent motor fluctuations in Parkinson's disease.

Early combination therapy with bromocriptine (Br) and levodopa (LD) is believed to delay or prevent the onset of late treatment complications typically associated with LD monotherapy in Parkinson's disease (PD). Studies recommending this regimen have been uncontrolled. We evaluated this possibility in a 4-year, double-blind, randomized, parallel group trial comparing Br and LD both alone and in combination in 22 PD patients never before treated with dopaminergic medications. In the group receiving Br monotherapy, 17% had motor fluctuations (end-of-dose failure or on-off), 17% chorea, 33% dystonia, and 83% freezing. In the LD group, 33% had motor fluctuations, 56% chorea, 100% dystonia, and 22% freezing. In the combination group, 71% had motor fluctuations, 57% chorea, 71% dystonia, and 57% freezing. The frequency of dystonia was significantly lower with Br monotherapy than in the other two treatment groups. No other significant differences were observed. LD monotherapy appeared to have superior efficacy in the treatment of PD. Mean final doses of LD and Br were similar for the different treatment groups. Early combination therapy does not prevent or delay the onset of motor fluctuations or dyskinesia in PD.

Activities of Daily Living↗
PubMed1991

Occult neurovesical dysfunction in children with imperforate anus and its variants.

Neurovesical dysfunction (NVD) is frequently encountered in children with imperforate anus and its variants. Such functional urologic problems are often compounded by associated anatomic urologic abnormalities that in combination may profoundly alter the course and prognosis of children with imperforate anus. Herein, we report 16 such cases. Management of NVD in children with imperforate anus offers several unique challenges that require important alterations in management. Specific recommendation are presented.

Anus, Imperforate↗
PubMed1990

Percutaneous transperineal pouch localization in low imperforate anus: a new approach.

Patients who have an imperforate anus with associated infralevator, or low rectal pouch, are candidates for a perineal anoplasty. However, in the absence of a perineal fistula, intraoperative localization and isolation of the rectal pouch can be difficult. We have developed a technique to facilitate isolation and dissection of the rectal pouch for perineal anoplasty in patients with a low imperforate anus who do not have a perineal fistula present. Pouch localization is carried out preoperatively by fluoroscopic percutaneous transperineal placement of a Fogarty embolectomy catheter through the center of the anal wink. We have used this technique successfully in four consecutive patients who had a low imperforate anus, in the absence of a perineal fistula, with the pouches 1.0 to 1.5 cm from the perineum. Results have been excellent, and the dissection of the rectal pouch was facilitated greatly by the presence of the inflated Fogarty balloon.

Anal Canal↗
PubMed1990

The use of prostaglandin F2 alpha for the prophylaxis of cyclophosphamide induced cystitis in rats.

It is well-established that cystitis is a significant cause of morbidity after cyclophosphamide administration in clinical populations. We induced hemorrhagic cystitis in rats using cyclophosphamide and compared controls to those pretreated with prostaglandin F2 alpha. Rats were then evaluated for differences in bladder weights, gross edema, gross bleeding, and histologic changes. The weights of the bladders which had been treated with cyclophosphamide were 94% greater than the controls. The weights of the bladders which were pretreated with prostaglandin F2 alpha before cyclophosphamide were only 19% greater than controls. Significant differences were found between cyclophosphamide controls and prostaglandin F2 alpha pretreated groups for gross weight (p less than .0005), gross edema (p less than .0005), and histology (.0005 less than p less than .005). We conclude that prostaglandin F2 alpha may be helpful in preventing cyclophosphamide induced cystitis.

Animals↗
PubMed1985

The prevalence of carotid artery disease in patients presenting with amaurosis fugax.

Ninety-five patients with amaurosis fugax were investigated for extracranial carotid artery disease. A doppler system combining imaging with spectrum analysis was used. Stenosis (greater than 25 per cent) and occlusion of the ipsilateral extracranial internal carotid artery occurred in 30 per cent and 26 per cent of patients respectively. The association of amaurosis fugax with ipsilateral carotid disease is highly significant. The role of this Doppler technique in the investigation of patients with amaurosis fugax is considered.

Adult↗
PubMed1981

Haemodynamic assessment following iliac artery dilatation.

Fourteen patients with symptomatic atheromatous stenoses of common or external iliac arteries underwent percutaneous arterial dilatation. Twelve procedures were considered successful in terms of arteriographic and symptomatic improvement but the application of three haemodynamic indices (pressure index, pulsatility index and the papavarine test) indicated that only 8 patients had gained a significant improvement in blood flow. These results illustrate the need for quantitative measurements in the assessment of this new technique.

Angioplasty, Balloon↗
PubMedDate not supplied

Magnetic resonance imaging evaluation of the patellar tendon after use of its central one-third for anterior cruciate ligament reconstruction.

Magnetic resonance imaging was used to evaluate the remaining patellar tendon after its central one-third had been harvested for anterior cruciate ligament reconstruction. Twenty patients were studied at either 6 weeks, 4, 6, 9, or 18 months postoperatively. The average thickness, width, cross-sectional area, and signal intensity of the operated and contralateral non-operated tendons were calculated and compared for each magnetic resonance imaging scan. A significant increase in the thickness was noted at all periods of followup, but no change in width occurred despite the defect being closed at the time of surgery. High signal intensity was present in the early periods, which signified edema and scar tissue. Signal intensity decreased at subsequent follow-up periods until at 18 months the operated tendon appeared normal. These findings indicate that the patellar tendon has the potential to regenerate and remodel in the postoperative period.

Adult↗