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Biomedical subjects

A Hayes

Publications and source records attributed to A Hayes.

At least 109 records · Page 6Linked to original sources
PubMed1991

A 52 kD cytoskeletal protein from retinal rod photoreceptors is related to erythrocyte dematin.

A novel cytoskeletal antigen, RET52, has been identified in the mouse retina. This 52 kD polypeptide is antigenically related to dematin (band 4.9), an actin-bundling phosphoprotein component of the erythrocyte membrane skeleton. Like dematin, RET52 is also a substrate for cAMP-dependent protein kinase. Within the retina, RET52 is primarily concentrated in two regions-the rod inner segment and the outer synaptic layers-although the developmental expression of RET52 differs in these areas. RET52 is present at birth in the inner segment, but appears about the time of initial synapse formation (postnatal day 4-6) in the outer plexiform layer. No differences in RET52 expression have been detected in early-stage mouse retinas with the retinal degeneration (rd) phenotype. RET52 localization, developmental expression, homologies to dematin, and in vitro phosphorylation pattern suggest a possible role for cytoskeleton-associated proteins in the initiation or control of disk membrane assembly and/or synapse formation in the rod photoreceptor.

Animals↗
PubMed1990

Magnetic resonance imaging of the great arteries in infants.

Sixty infants, aged 1-48 (median 8) weeks, with suspected congenital heart disease underwent a morphological evaluation of the great arteries using magnetic resonance imaging at 1.5 Tesla. Cross-sectional echocardiography was performed in all infants, angiography in 33 and surgery in 44. Multiple sections, 5 mm thick and gated to the patients' electrocardiogram were acquired in standard and oblique imaging planes. Ventriculo-arterial connexions were correctly identified in 54 infants (6 did not have intracardiac imaging performed) and an accurate description of the relationships of the great arteries was made in all. Magnetic resonance imaging clearly demonstrated normal and hypoplastic pulmonary arteries to the level of the first hilar branches and was better than echocardiography at confirming the presence or absence of central intrapericardial pulmonary arteries in 4 infants with pulmonary atresia. All parts of the thoracic aorta were accurately demonstrated and, in 23 infants with clinical suspicion of aortic coarctation, magnetic resonance images provided more information than echocardiography. Magnetic resonance imaging accurately demonstrates great arteries non-invasively supplementing echocardiographic and angiographic findings. In many cases, it replaces the need for invasive investigations.

Aorta, Thoracic↗
PubMed1990

Morphological evaluation of atrioventricular septal defects by magnetic resonance imaging.

Twelve patients aged between 2 weeks and 22 months (median 6 weeks) with atrioventricular septal defects were examined with a 1.5 T, whole body, magnetic resonance imaging system. Ten patients had a common atrioventricular orifice (complete defect) while two patients had separate right and left valve orifices (partial defect). Associated cardiac malformations included the tetralogy of Fallot in two, isomerism of the right atrial appendages and pulmonary atresia in two, and right isomerism and double outlet right ventricle in one. All had previously been examined by cross sectional echocardiography. Eight subsequently had angiography and six underwent surgical correction. There was one operative death and three other deaths. Three of these patients underwent postmortem examinations. Small children and infants were scanned inside a 32 cm diameter head coil. Multiple electrocardiographically gated sections 5 mm thick, separated by 0.5 mm, were acquired using a spin echo sequence with echo time of 30 ms. A combination of standard and oblique imaging planes was used. Magnetic resonance imaging was more accurate than echocardiography in predicting the size of the ventricular component of the defect. It was also better than either echocardiography and angiography in identifying the presence of ventricular hypoplasia. All these findings were confirmed by surgical or postmortem examinations or both. Magnetic resonance imaging is capable of providing detailed morphological information in children with atrioventricular septal defects which is likely to be of value in their management.

Abnormalities, Multiple↗
PubMed1989

Hemodynamic effects of nitroglycerin in an experimental model of acute aortic regurgitation.

Afterload reduction is an accepted therapeutic modality for the treatment of congestive heart failure caused by chronic aortic regurgitation. However, the role of vasodilator therapy in acute aortic incompetence has not been established. To investigate this, left ventricular volume overload was produced in 18 dogs by constructing a valved conduit from the descending thoracic aorta to the left ventricular apex. The time course of aortic, pulmonary and conduit flows was analyzed in eight control studies and established stability of the experimental model. In the remaining 10 dogs, intravenous nitroglycerin, titrated to reduce mean aortic blood pressure by 40%, and placebo (ethanol) were each infused for 20 min periods. Compared with placebo, nitroglycerin significantly reduced aortic flow (3,945 +/- 324 to 3,397 +/- 362 ml/min, p less than 0.01), regurgitant flow (1,304 +/- 131 to 764 +/- 90 ml/min, p less than 0.001), septal-lateral end-diastolic diameter (47.5 +/- 1.8 to 46.5 +/- 1.8 mm, p less than 0.001), left ventricular end-diastolic pressure (6.9 +/- 0.8 to 6.0 +/- 0.6 mm Hg, p less than 0.05), left ventricular stroke work (19.0 +/- 2.6 to 10.8 +/- 1.7 g-m/beat, p less than 0.001) and systemic vascular resistance (2,253 +/- 173 to 1,433 +/- 117 dyne-s/cm5, p less than 0.001). In contrast, pulmonary flow, left anterior descending coronary flow and subendocardial pH did not change during infusion of either nitroglycerin or placebo. These data indicate that by decreasing preload and afterload, and by preserving coronary flow and tissue pH, nitroglycerin effectively reduced ventricular and regurgitant volumes in the setting of acute volume overload.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Recognition of an in vivo immune response to human neuroblastoma modulation of antigen expression by retinoic acid.

Neuroblastoma is one of the most common solid tumors of childhood and is notable for its ability to spontaneously regress and, in some instances, to differentiate to less malignant ganglioneuromas. Since immune mechanisms may account for these phenomena, identification of in vivo immune responses to tumor cell surface antigens may be important to the progression of the disease. As determined by analysis on the fluorescence-activated cell sorter, sera from 10 of 18 neuroblastomas patients were found to contain antibodies to a cell surface antigen present on subpopulations of cells from human neuroblastoma cell lines maintained in vitro. Eight human neuroblastoma cell lines were examined and found to vary in reactivity with sera. Induction of differentiation of cell lines with retinoic acid (RA) in vitro resulted in most cell lines bearing higher percentages of positive cells but with a decreased mean cell fluorescence. Preliminary Western blot analysis of lysates of the human cell lines NMB/N7, SMS-KAN, and SK-N-MC showed two principal antigen bands on reducing gels. Comparison of sera from different individuals on lysates of cell lines showed reactivity principally with bands of 105-110 kD and 65-70 kD and an additional minor band of slightly lower molecular weight with the higher titer sera. The ability of different sera to recognize a common antigen pattern suggests that this represents an immunodominant cell surface antigen. Examination of reactivity of other cell lines in this system showed that positive sera reacted with all neuroblastoma lines examined, one neuroepithelioma (SK-N-MC), two melanoma lines (MeWo, G361), and one adrenal-derived adenocarcinoma (SW-13).

Antibody Formation↗
PubMed1989

Frictional response of articular cartilage containing crystals.

Many joint diseases are associated with the deposition of crystals in articular cartilage. Three main types are commonly found: calcium pyrophosphate, calcium hydroxyapatite and monosodium urate. The effects of these articular crystals on the frictional properties and the surface condition of the articular cartilage were studied. A total of 43 cartilage specimens cut from 19 post-mortem knee joints have been tested in purpose-designed apparatus. The results show that a high friction coefficient and a high level of crystal deposition tend to occur with a worsening of the surface quality of the articular cartilage.

Biocompatible Materials↗
PubMed1989

Serum levels of beta-carotene, vitamin A, and zinc in male lung cancer cases and controls.

The mean serum levels of beta-carotene and vitamin A in a multivariate analysis of data from 64 histologically confirmed male lung cancer cases were statistically significantly lower than those from 63 randomly selected male hospital controls, who were admitted for small surgical operations (p values for both beta-carotene and vitamin A less than 0.001). The mean serum levels of zinc were not statistically significantly different between cases and controls (p = 0.10). The levels of beta-carotene, vitamin A, or zinc were not statistically significantly influenced by either the extent of the cancer (p = 0.45) or the cancer cell type (p = 0.06). The possible biological significance of these findings is discussed briefly.

Adenocarcinoma↗
PubMed1989

Dietary and alcohol intake, smoking pattern, occupational risk, and family history in lung cancer patients: results of a case-control study in males.

In a case-control study of 71 consecutive new male cases of lung cancer and 71 male hospital control patients, previous dietary and alcohol intake, smoking pattern, occupation, dust exposure, and family history of lung cancer were investigated. The cases and controls were similar in age, country of origin, area of residence, and marital status. Using a frequency-based assessment of previous dietary intake, broad food groups were similar for cases and controls. Cases had a significantly lower intake of fish than controls did (odds ratio = 0.5, confidence interval = 0.2-1.0, p = 0.05). A protective effect for fish consumption in lung cancer has not been previously reported. The dietary intake of foods containing retinol and beta-carotene and the intake of alcohol were not significantly different between cases and controls. For cases, smoking duration was longer and the time since cessation for exsmokers was shorter, cigarette pack years were longer, and the number of cigarettes smoked per day was greater. The factors of occupation, dust exposure, and family history of cancer (including lung cancer) were similarly distributed between cases and controls.

Adenocarcinoma↗
PubMed1989

Superior QRS axis in ventricular septal defect.

The relation between the superior orientation of the QRS axis and the anatomical site of the defect in the ventricular septum in patients with a ventricular septal defect was studied. Of 1031 patients with a ventricular septal defect, 64 (6.2%) had a superior axis on their electrocardiogram. In 59% of these patients the defect was in the inlet portion of the ventricular septum or affected this area. None of the cases was classified as an isolated ventricular septal defect of the persistent atrioventricular canal type. While there is an association between a superior axis and perimembranous inlet ventricular septal defect, a superior QRS axis does not characterise a ventricular septal defect as being of the atrioventricular canal type.

Echocardiography↗
PubMed1988

Neonatal screening and an intensive management programme for galactosaemia: early evidence of benefits.

A prospective study of children with galactosaemia is being undertaken at the Metabolic Clinic, Royal Children's Hospital, Brisbane. The purpose of the study is to collect biochemical, clinical, dietary, developmental and speech and language data. This paper describes the operation of the multiprofessional management programme and reports results for two groups of children: those who were diagnosed before the introduction of neonatal screening in 1982 (the prescreening group) and those who were identified by screening. The eight children in the prescreening group have shown intellectual development in the low-average to moderately-handicapped range. Most of them have speech and language difficulties. The screening group, all of whom are still in infancy or early childhood, appears to be developing normally, with the exception of one child who is showing problems with speech and language. The early results provide a basis for cautious optimism that neonatal screening and careful management will result in improved outcomes for children with galactosaemia.

Galactosemias↗
PubMed1988

The detection of conventional class I and class II I-E homologue major histocompatibility complex molecules on feline cells.

The presence on feline cells of class I and class II I-E type major histocompatibility complex (MHC) homologues was demonstrated using cross-reacting monoclonal antibodies (mAb). The feline class I antigen homologues were detected with both immunofluorescent and biochemical techniques, using the anti-human class I mAb W6/32. The class I antigens were detected on in vitro cultured feline fibroblasts and lymphoid cells, but not on fresh lymphoid cells, apparently as a result of the association of bovine beta-2 microglobulin with feline class I heavy chains which generated the determinant(s) recognized by mAb W6/32. Class II I-E-like molecules could be detected with immunofluorescent techniques using the species cross-reactive anti-mouse I-E antibody 40D only when peripheral blood mononuclear cells were activated, for example, with the mitogens staphylococcus enterotoxin A or lipopolysaccharide. The predominant expression of I-A-like molecules by resting class II-positive feline cells could explain some of the functional difference we have seen in comparison with those of most other mammalian species.

Animals↗
PubMed1988

Identification of two-tone images; some implications for high- and low-spatial-frequency processes in human vision.

Unlike most multitone images, two-tone images such as print, geometric figures, and line drawings are as easy to interpret in photographic negative as in positive form. However, images derived from a multitone original in which intensity values are quantised to two levels are not. Bi-level quantised images, distinct from most other two-tone images, are shown to contain picture related components in their low spatial frequencies. Since it is the low-spatial-frequency components alone of negative images that present difficulties for vision, it is proposed that images which are as easy to interpret in negative as in positive form are those which are readily identified using only their high spatial frequencies.

Adult↗
PubMed1988

Aspects of structure and content of maternal talk with infants.

Content of maternal talk in six mother-infant dyads was used to determine whether mothers timed their talk to infants as they would when conversing with an adult. Results indicated that maternal talk of an informative nature (Type 1 acts) tended to follow a brief intervening interval of silence, while maternal talk containing little or no information (Type 2 acts) tended to occur when the mothers "talked with" (covocalized with) their infants. In addition, there was a significant trend for the overall proportion of Type 1 acts to increase over infant age. These findings support the view that, during mother-infant engagements, mothers behave like sophisticated conversational partners.

Child Language↗
PubMed1988

Increased pulmonary gamma interferon production in asbestosis.

In order to determine if disordered cellular immune processes are present in the lungs of persons with asbestosis, we performed bronchoalveolar lavage (BAL) on 26 patients with either crocidolite- or chrysotile-induced pulmonary asbestosis and measured the spontaneous release of gamma interferon (IFN gamma), a marker of increased cellular immune activity. For comparison, 18 control subjects and 7 patients with active pulmonary sarcoidosis were also studied. Recovered BAL cells were cultured for 24 h (5 x 10(6)/ml), and the supernatant was assayed for interferon by determining inhibition of cytopathic effect on encephalomyocarditis virus-induced lysis of WISH cells and characterized by monoclonal anti-IFN gamma antibody inhibition. Nine (35%) patients with asbestosis released increased amounts of IFN gamma, up to 320 units/ml, the levels seen in the sarcoidosis patients. All control subjects released less than or equal to 10 units/ml. All interferon released was IFN gamma. In asbestosis patients, IFN gamma production was not related to a history of cigarette smoking, there was no significant difference in the ratio of helper/inducer (Leu-3) to suppressor/cytotoxic (Leu-2) cells in IFN gamma producers compared to non-IFN gamma producers (p greater than 0.05), and IFN gamma production correlated significantly with serum IgG levels (p less than 0.001) but not with the levels of IgM, IgA, antinuclear factor, or rheumatoid factor. These data suggest that active cellular immune processes are present in the lungs of a proportion of patients with asbestosis.

Asbestosis↗
PubMed1988

The superiority of continuous cold blood cardioplegia in the metabolic protection of the hypertrophied human heart.

The effects of sanguineous and asanguineous cardioplegia on the generation of myocardial acid in the hypertrophied human heart during aortic clamping and reflow were elucidated by continuous intraoperative monitoring of myocardial pH in 42 patients undergoing valve replacement, with or without coronary bypass. The patients were divided into three groups: Group I (n = 14) received intermittent crystalloid cardioplegia; group II (n = 14) received intermittent blood cardioplegia; and group III (n = 14) received continuous blood cardioplegia. The groups were matched according to six previously elucidated determinants of myocardial acidosis. Measurements were made of myocardial pH, hydrogen ion concentration ([H+]), and the difference in pH units between myocardial pH and the pH of neutrality of water at the corresponding temperature (delta pHn). Throughout aortic clamping, myocardial pH in groups I and II fell significantly by 0.46 +/- 0.08 and 0.15 +/- 0.07 units, respectively (p less than 0.001) between the groups). In contrast, myocardial pH remained statistically unchanged throughout aortic clamping in group III (p less than 0.001 compared to groups I and II). Similar relationships were observed in [H+] and delta pHn during aortic clamping. During the early reflow, myocardial acidosis was observed in all three groups and delta pHn in group III increased from -0.26 +/- 0.10 at the end of aortic clamping to -0.57 +/- 0.07 during reperfusion (p less than 0.03). Patients in groups II and III required significantly less inotropic and mechanical cardiac support than patients in group I (p = 0.017). Hence, although continuous blood cardioplegia does not completely prevent acid accumulation during reflow, it provides better metabolic protection of the hypertrophied human heart than either intermittent crystalloid or intermittent blood cardioplegia.

Aged↗
PubMed1987

Radionuclide therapy of neural crest tumors.

The potential concentration of I 131-Meta-iodo-benzylguanidine (MIBG) in pheochromocytoma, and the successful application in diagnosis and therapy of pheochromocytoma, has led to its use in therapy in other tumours derived from the neural crest. In neuroblastoma, the concentration of MIBG is as reliable as it is in pheochromocytoma. 18 patients with a neuroblastoma were treated, leading to two complete remissions, seven partial remissions, two no change, and two progressive disease; one patient was lost for follow-up. Six adults were treated, three with a carcinoid, two malignant pheochromocytoma and one medullary thyroid carcinoma. Although follow-up is still short, preliminary results of therapeutic use of I 131-MIBG indicate that this treatment modality may be effective.

3-Iodobenzylguanidine↗
PubMed1986

A case of uridine diphosphate galactose-4-epimerase deficiency detected by neonatal screening for galactosaemia.

An infant with a deficiency of the enzyme uridine diphosphate galactose-4-epimerase was detected during galactosaemia screening of the Queensland newborn population. No case of epimerase deficiency has been reported previously in Australia and the incidence in our population is unknown. A deficiency of this enzyme is usually quite benign although two cases with a galactosaemia-like syndrome have been reported. This infant is developing normally, both intellectually and physically, in spite of extremely high levels of red blood cell galactose-1-phosphate. The introduction of newer methods of galactosaemia screening in Australia will probably result in the detection of other cases of this enzyme deficiency.

Australia↗