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Biomedical subjects

C Barry

Publications and source records attributed to C Barry.

At least 19 recordsLinked to original sources
PubMed1992

Induced chorioretinal venous anastomosis in experimental retinal branch vein occlusion.

Iatrogenic retinal vein to choroidal vein anastomoses were created using laser photocoagulation in six of seven dog eyes in which a partial branch retinal vein occlusion had previously been created photochemically. A similar attempt to create an anastomosis was made in six control eyes in which no branch vein occlusion was present. In the eyes in which a branch retinal vein had been created, a venous chorioretinal anastomosis appeared to be present by 3 to 6 weeks. In three control eyes similar venous anastomosis was created; however this took 6 to 8 weeks to develop and was of much smaller calibre than the one that developed in the presence of a partial branch retinal vein occlusion. No adverse complications were noted in the period of the study (3 months). This study demonstrates that chorioretinal venous anastomoses can be created and may be of use in the treatment of partial retinal vein occlusions that show signs of progression.

Anastomosis, Surgical↗
PubMed1992

Intracellular pH in OK cells. II. Effects of temperature on cell pH.

Intracellular pH (pHi) is known to acidify as temperature rises. It has been proposed that this relationship reflects the temperature dependence of the dissociation constant of intracellular buffers. The purpose of this study was to evaluate whether H+ production and membrane acid/base transport events also contribute to the temperature dependence of pHi. This relationship was studied by means of the 490/450-nm fluorescence of 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, to measure pHi of OK cells grown on cover slips and perfused in a thermostated chamber. As temperature was increased from 12 degrees C, pHi progressively acidified, until a precipitous and large alkalinization appeared at 40-45 degrees C. We specifically examined the range from 25 to 37 degrees C, over which pHi acidified by 0.32 units from 7.50 to 7.18. The three major components that regulate pHi in the OK cell were quantitated as follows: H+ production, H+ extrusion via Na(+)-H+ antiport, and the passive H+ leak from buffer to cell. Relative to the rate at 25 degrees C, acid production at 37 degrees C increased by 129% (3.82 +/- 0.78 vs. 8.76 +/- 1.12 mmol.l-1.min-1). The recovery of pHi after NH4Cl loading was used to measure the rate of Na(+)-H+ antiport, and in Na(+)-free depolarized cells the magnitude of passive H+ conductance through the leak pathway. Compared with the rate at 25 degrees C, at 37 degrees C the Na(+)-H+ antiport increased by 26% (1.25 +/- 0.22 vs. 1.58 +/- 0.25 mmol.l-1.min-1) and the H+ permeability increased by 140% (0.005 +/- 0.001 vs. 0.012 +/- 0.003 cm/s).(ABSTRACT TRUNCATED AT 250 WORDS)

Amiloride↗
PubMed1992

Avascular necrosis of the femoral head post heart-transplantation and steroid dosage.

Avascular necrosis (avn) post heart-transplantation has been considered to be due to the high doses of steroids used to immunosuppress these patients in attempting to prevent transplant rejection. This study shows that avascular necrosis occurs even when low dose steroids regimes are used and demonstrates no significant correlation between steroid dosage and the development of avn. Patients with symptomatic avn benefit from early diagnosis and management of their condition in that the need for total joint arthroplasty can be prevented in many cases.

Adult↗
PubMed1992

Low energy high frequency pulsed electromagnetic therapy for acute whiplash injuries. A double blind randomized controlled study.

The standard treatment of acute whiplash injuries (soft collar and analgesia) is frequently unsuccessful. Pulsed electromagnetic therapy PEMT (as pulsed 27 MHz) has been shown to have pro-healing and anti-inflammatory effects. This study examines the effect of PEMT on the acute whiplash syndrome. One half of the 40 patients entering the study received active PEMT collars: the other half facsimile (placebo). All patients were given instructions to wear the collar for eight hours a day at home and advised to mobilise their necks. At 2 and 4 weeks the actively treated group had significantly improved (p less than 0.05) in terms of pain (visual analogue scale). By chance movement scores for the PEMT group were significantly worse at entry to the study than the control group (p less than 0.05). At 12 weeks they had become significantly better (p less than 0.05). PEMT as described is safe for domiciliary use and this study suggests that PEMT has a beneficial effect in the management of the acute whiplash injury.

Accidents, Traffic↗
PubMed1991

Magnetic resonance imaging in the assessment of rheumatoid arthritis--a comparison with plain film radiographs.

Conventional radiography lacks sensitivity in early rheumatoid disease. MRI with its advantages of soft tissue discrimination and multiplanar imaging facility might detect earlier disease. This study compares the MR images and conventional radiographs of 11 rheumatoid patients' wrists and carpi. In all cases, erosions were more extensive and numerous on the MR images compared to plain radiographs. MR is useful in detecting early aggressive disease and in monitoring the response to treatments.

Adult↗
PubMed1991

Intracellular pH in the OK cell. I. Identification of H+ conductance and observations on buffering capacity.

The regulation of intracellular pH (pHi) in the opossum kidney (OK) cell line was studied in vitro using the pH-sensitive excitation ratio of 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. Recovery from an NH4Cl acid load disclosed a Na-dependent component blocked by amiloride and a smaller Na-independent component. The Na-independent recovery rate was proportional to the H+ gradient from cell to buffer and was zero in the absence of an electrochemical gradient. The Na-independent recovery was not affected by N-ethylmaleimide, dicyclohexylcarbodiimide, HCO3, phloretin, or ZnCl2 but was accelerated in depolarized cells and by membrane-fluidizing drugs and was inhibited by glutaraldehyde. The apparent cellular buffering capacity changed in proportion to this H+ conductance. Consistent with an electrogenic H+ leak, steady-state cell pH alkalinized with depolarization and acidified with hyperpolarization. Removal of buffer Na+ produced a profound acidification, as did amiloride. In 0-Na+ buffers, extremely large cell-to-buffer H+ gradients were present and proportional to buffer pH. 4-Acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid had no effect on steady-state pHi. Measurements of intracellular buffering capacity were derived from the change of cell pH induced by withdrawing NH4Cl. This buffering capacity was increased threefold in Na-free buffers, whereas the value measured by direct titration of cell lysate was the same or less than that of control cells. The NH4Cl-derived buffering capacity varied in direct proportion to the magnitude of the H+ leak. Drugs that changed H+ permeability produced the apparent changes of the measured buffering capacity within a few minutes. We conclude that, in HCO3-free buffer, the OK cell uses two membrane acid-base transport pathways: a Na-H antiporter active at physiological pH and a substantial passive H+ conductance. The results also reveal that the NH4Cl-derived buffering capacity is subject to artifacts, possibly due to a finite leak of ionic NH4+.

Amiloride↗
PubMed1991

Skeletal tuberculosis.

Skeletal tuberculosis is an uncommon form of tuberculosis. During the period 1977-87, the number of cases diagnosed in two Dublin hospitals has remained at a constant level. The present study reports on 36 adults with skeletal tuberculosis and shows more frequent extraspinal involvement than other studies. The long duration of symptoms prior to diagnosis of 10.79 (+/- 8.8) months suggests that tuberculosis is not being considered early in the course of unexplained inflammatory arthritides especially in the elderly patient. The under utilisation of the Mantoux test in diagnosis is also a matter of concern.

Adolescent↗
PubMed1990

Cultural differences in family communication about Duchenne muscular dystrophy.

This study compared the patterns of communication and use of professional support systems of Irish and American families with sons with Duchenne muscular dystrophy (DMD). Structured interviews were used with the parents of 34 Irish boys and 21 American boys attending the muscular dystrophy services of Central Remedial Clinic, Dublin, and Children's Hospital, Boston. A matched control group was interviewed in each culture to compare use of professional support systems. Difficulties in communicating about DMD with their spouses and with their affected sons were reported by significantly more Irish parents than by their American counterparts. More Irish parents had never spoken about DMD with their affected sons. American DMD families reported significantly more contact with professional support systems than did the Irish families. Factors which may contribute to these cultural differences are discussed.

Adaptation, Psychological↗
PubMed1990

Cerebral palsy: social class differences in prevalence in relation to birthweight and severity of disability.

STUDY OBJECTIVE: The aim of the study was to examine the possible influence of social class on the prevalence of cerebral palsy. DESIGN: The study was a retrospective population based survey of all cases of cerebral palsy. SETTING: The study involved all cases of cerebral palsy born to residents in the Eastern Health Board area of the Republic of Ireland between 1976 and 1981 inclusive. PATIENTS: There were 289 cases of cerebral palsy during the study period. Thirty one were excluded because they were attributable to postneonatal brain damage, leaving 258 children for analysis. Cases with uncertain diagnosis were excluded. MAIN RESULTS: There was a clear social class gradient in the overall prevalence of cerebral palsy, also evident in the individual syndromes of hemiplegia and diplegia. No such gradient was detected in the other syndromes, either singly or in combination. Among cases of low birthweight (less than or equal to 2500 g), the prevalence was the same across the social class range after allowing for the increased low birthweight rate in the lower social class categories. Among normal birthweight cases there was a strong positive association with decreasing social class. Intrauterine growth retardation seemed to be a factor in cerebral palsy in all social class groups. Prevalence of cerebral palsy severe enough to prevent walking by the fourth birthday, but not of cases ambulant by this age, increased with socioeconomic disadvantage. CONCLUSIONS: The clear social class gradients in hemiplegia and diplegia suggest that environmental factors play an important role in the aetiology of these syndromes, but there was no evidence of a contribution from this type of factor in the remaining types of cerebral palsy.

Birth Weight↗
PubMed1990

A comparison of two formulations of indomethacin ('Flexin Continus' tablets and 'Indocid' capsules) in the treatment of rheumatoid arthritis.

A multi-centre, double-blind, crossover study was carried out in 80 patients with rheumatoid arthritis to compare the efficacy and side-effect profiles of two formulations of indomethacin. Patients were allocated at random to receive 75 mg indomethacin per day either as 1 controlled-release tablet at night or as 1 immediate-release capsule given 3-times a day for a period of 4 weeks before being crossed over to receive the alternative treatment for a further 4 weeks. Pain scores, daily symptomatology and the requirement for escape analgesia recorded by both investigator and patient indicated that controlled-release indomethacin tablets, 75 mg given at night, was as efficacous as immediate-release indomethacin capsules given 3-times daily. However, the controlled-release formulation had a superior side-effect profile with a reduced incidence of abdominal/epigastric pain compared to the immediate-release preparation.

Administration, Oral↗
PubMed1990

Pulsed high frequency (27MHz) electromagnetic therapy for persistent neck pain. A double blind, placebo-controlled study of 20 patients.

In the majority of patients with neck pain, symptoms will resolve spontaneously or quite quickly in response to therapy. However, some patients' symptoms persist for a long period, irrespective of therapy. In this study, 20 patients with persistent (greater than 8 weeks) neck pain were enrolled in a double blind, placebo-controlled trial of low energy, pulsed electromagnetic therapy (PEMT)--a treatment previously shown to be effective in soft tissue injuries. For the first 3-week period, group A (10 patients) received active PEMT units while group B (10 patients) received facsimile placebo units. After 3 weeks, both pain (visual analogue scale (P less than .023) and range of movement (P less than .002) had improved in the group on active treatment compared to the controls. After the second 3 weeks, during which both groups used active units, there were significant improvements in observed scores for pain and range of movement in both groups. PEMT, in the form described, can be used at home easily in the treatment of patients with neck pain. It is frequently successful and without side effects.

Adult↗
PubMed1990

The importance of standardised radiographs when assessing hip dysplasia.

The reliability of radiological criteria in the diagnosis of congenital dislocation of the hip is discussed. In a review of 20 normal infant patients the variability of the radiographic relationship between the ossific nucleus of the proximal femoral epiphysis and the acetabulum is identified. Hip arthrography in 10 patients and pathological examination of femoral heads confirm that the ossific nucleus lies superiorly within the infant femoral head and may be displaced from the true centre of the femoral head by up to 40% of it's radius. As the ossific nucleus of the capital femoral epiphysis is shown to originate eccentrically within the spherical cartilaginous anlage it is suggested that standardisation of hip radiographs is required in the routine clinical assessment of the infant hip, particularly in the presence of dysplasia.

Arthrography↗
PubMed1989

Radiation sensitivity of glial cells in primary culture.

Primary cultures from newborn mouse brain were subjected to ionizing radiation to determine the sensitivity of galactocerebroside-positive oligodendrocytes and A2B5-positive progenitor cells during development. The radiosensitivity or D0 of the 2 cell populations was determined by measuring the fraction of surviving cells after various doses of x-rays. When the cultures were exposed to a single dose of x-rays at 6 days, oligodendrocytes showed a D0 of 1.4 Gy, and A2B5-positive cells a D0 of 4.5 Gy. When the cultures were exposed to a single dose of x-rays at 12 days, oligodendrocytes showed a D0 of 4.4 Gy, indicating that they have become more radioresistant. Cultures exposed to a dose of 1.5 Gy and monitored from 9 h to 2 weeks after irradiation showed a reduced but constant number of galactocerebroside-positive cells at all time points. Since galactocerebroside-positive oligodendrocytes are non-dividing or slowly dividing cells, the radiosensitivity of young oligodendrocytes was attributed to interphase cell death. These results indicate that young differentiated oligodendrocytes are more radiosensitive than other glial cell types, and that there is no significant replacement of lost oligodendrocytes either through proliferation or through differentiation of progenitors after irradiation in the culture system.

Animals↗
PubMed1989

A serial study of anticardiolipin antibody and antimitochondrial antibody type M5 in a patient with polyarthritis and polymyositis.

A 22-year-old female presented with polyarthritis and subsequent polymyositis. Initially, she had moderately high levels of anticardiolipin (aCl) and antimitochondrial antibody (AMA) type M5. Following corticosteroid therapy, the anticardiolipin antibody rapidly fell to background levels but reappeared with the onset of two significant clinical events.

Adult↗
PubMed1988

Expression of myelin basic protein mRNA and polypeptides in mouse oligodendrocytes in culture: differential regulation by genetic and epigenetic factors.

We have analyzed the effects of genetic and epigenetic factors on the steady-state levels of myelin basic protein mRNA and polypeptides during development of mouse oligodendrocytes in culture. Oligodendrocytes were characterized by immunofluorescent staining with antibodies for the following markers: galactocerebroside, myelin basic protein, proteolipid protein, myelin-associated glycoprotein and 2',3'-cyclic nucleotide phosphohydrolase. Oligodendrocytes expressing one or more of these markers first appeared at 3 days in culture and increased to a maximum of 1.5 X 10(5) per brain around 6 days, after which the number remained constant up to 31 days. In medium containing fetal calf serum, accumulation of myelin basic protein polypeptides was delayed relative to in vivo in cultures derived from C57BL/6J, BALB/cJ and DBA/2J inbred mice, but not in cultures derived from C3H/HeJ and AKR/J inbred mice. In medium containing serum from other species or in serum substitute, the temporal expression of myelin basic protein polypeptides in cultures from all the inbred strains was contemporaneous with that in brain. Northern hybridization analysis indicated that the steady-state level of myelin basic protein-specific mRNA in all cultures was regulated similarly to in vivo suggesting that the delayed expression of myelin basic protein polypeptides in some cultures was due to translational and/or post-translational regulation. Analysis of myelin basic protein expression in cultures from informative hybrid and recombinant inbred strains indicated that translational or post-translational expression of myelin basic protein requires trans-acting factors, the inducibility of which is controlled by multiple genetic determinants which segregate independently and are expressed additively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗