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L Young

Publications and source records attributed to L Young.

At least 163 records · Page 9Linked to original sources
PubMed1994

A national policy on asthma management for schools. The Asthma Special Interest Group, Thoracic Society of Australia and New Zealand.

Since asthma is the most common chronic illness in childhood, many of the problems associated with this condition will impact on the child's education. Because of widespread concerns regarding the management of asthma in schools, a subcommittee of the Thoracic Society of Australia and New Zealand, Asthma Special Interest Group, was convened to draw up national guidelines for school staff in order to provide optimal management of asthma in the school setting. We used current medial literature and the clinical experience of the authors who have dealt with children and adolescents suffering from asthma in the hospital, community and school environment. A number of issues had been identified, including: the availability of an asthma first aid kit; correct use of bronchodilator aerosols by puffer and spacer devices; and clear instructions as to when to notify parents and when to call an ambulance to the school.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Oxidation of LDL to a biologically active form by derivatives of nitric oxide and nitrite in the absence of superoxide. Dependence on pH and oxygen.

A key factor in atherogenesis is oxidation of LDL in the subendothelial space. In the normal vessel wall or in the thickened intima of diseased vessels, this space is rich in nitric oxide (NO.) released from endothelial cells, smooth muscle cells, and macrophages. To determine whether NO. has a role in LDL oxidation, we exposed human LDL to NO. under aerobic and anaerobic conditions and at acidic and neutral pH. Spectrophotometric detection of beta-carotene in the LDL was used as a marker for LDL oxidation. Depletion of beta-carotene was observed in LDL treated with NO. under aerobic conditions but not under anaerobic conditions. In contrast, treatment of LDL with sodium nitrite did not require oxygen for beta-carotene depletion, although depletion was increased when O2 was present. Furthermore, low pH greatly accelerated LDL oxidation by either NO. gas or by nitrite (NO2-). Depletion of beta-carotene corresponded with formation of conjugated dienes, increased susceptibility to further oxidation, and aggregation of apolipoprotein B-100, but did not increase electrophoretic mobility of LDL. Also, nitrite-oxidized LDL demonstrated biological properties similar to minimally oxidized LDL, including stimulation of monocyte adhesion and inhibition of lipopolysaccharide-induced neutrophil binding to endothelium. These results indicate that NO. under certain circumstances may contribute to oxidative modification of LDL and may have a role in atherogenesis.

Animals↗
PubMed1994

Antigen retrieval using pH 3.5 glycine-HCl buffer or urea solution for immunohistochemical localization of Ki-67.

A new antibody (MIB-1) has been described, permitting the demonstration of Ki-67 proliferation antigen in paraffin sections. However, satisfactory results were obtained only after subjecting tissue sections to microwave based antigen retrieval in citrate buffer solution. Other buffer solutions produce equivalent or better results and also permit use of the original Ki-67 antibody, which hitherto has been considered ineffective for paraffin sections.

Buffers↗
PubMed1993

Epithelial-fibroblast interactions in bleomycin-induced lung injury and repair.

Intercellular communication between epithelial cells and fibroblasts of the alveolar wall contributes to regulatory control of each cell type. We examined whether lung injury and subsequent fibrosis are associated with disturbance of this mutual control system. Rats received bleomycin intratracheally, and after 10 days, when acute epithelial injury occurs, and at 6 weeks, when repair with fibrosis is found, pure populations of type 2 epithelial cells and lung fibroblasts were prepared to study interactions with respect to growth control. Epithelial cells were cultured alone, on a permeable filter over fibroblasts, and in co-culture with fibroblasts. The results showed that the low growth rate of normal epithelial cells increased when cells were exposed to fibroblast supernatants. This effect was also seen using cells from the 10-day bleomycin group, but it was diminished in the group treated for 6 weeks. However, epithelial cells from exposed or control rats did not show increased DNA synthesis when grown in contact with fibroblasts in co-culture. In contrast, fibroblast growth was inhibited when exposed to epithelial cell secretions in control cultures and when using cells from the 10-day bleomycin group. No inhibition of fibroblast growth by epithelial cells was found using cells from the fibrotic lungs. These results suggest that after lung injury by bleomycin, a fibroblast-secreted factor promotes epithelial growth; however, during repair, regenerating epithelial cells lose the ability to inhibit fibro-blast proliferation. These local changes in cellular control at the alveolar wall may be sufficient to produce pulmonary fibrosis.

Animals↗
PubMed1993

Rabies encephalitis in a patient with no history of exposure.

A 29-year-old man died of a rapidly progressive encephalitis without a clinical diagnosis and without a history of exposure to the rabies virus. A diagnosis of rabies was established postmortem by histologic and ultrastructural demonstration of rabies virus inclusions, by fluorescent antibody reaction, and by viral culture. Viral inclusions were sparse, were generally irregular and poorly demarcated, and were confined almost exclusively to the cerebellar Purkinje cells. A history of exposure was obtained only in retrospect on detailed questioning of friends and relatives. Rabies encephalitis is now seen most frequently in patients without a history of exposure and may be easily overlooked both clinically and pathologically.

Adult↗
PubMed1993

Restriction endonuclease digestion eliminates product contamination in reverse transcribed polymerase chain reaction.

Restriction endonuclease digestion was used to eliminate false-positive signals caused by polymerase chain reaction (PCR) product DNA contamination in a reverse transcribed (RT) PCR for amplifying rubella virus (RV) RNA sequences. A restriction enzyme selected to cut the PCR product DNA between, but not within, the primer binding sites was used to digest reaction mixtures after reverse transcription but before PCR amplification. Because restriction enzymes generally react only with specific double-strand sequences, contaminating DNA was rendered inactive while reverse-transcribed single strand cDNA was amplified. Assays showed that restriction enzyme digestion reduced template activity of product DNA by a factor of 10(7), while leaving sensitivity of the RT-PCR unaffected.

Animals↗
PubMed1993

Sickle cell disorders and chronic intravascular haemolysis are associated with low plasma heparin cofactor II.

Thrombotic events are known to be increased in patients with sickle cell syndromes and a variety of abnormalities of coagulation or endothelial function have been described, although the relevance of these findings either to the pathogenesis of vaso-occlusive phenomena or the risk of thrombosis are unclear. Heparin cofactor II (HCII) and antithrombin III are circulating inhibitors of thrombin and low plasma levels have been associated with an increased risk of thrombosis in otherwise healthy individuals. We describe for the first time abnormally low plasma levels of HCII in patients with sickle cell syndromes. 45 adult patients with sickle cell syndromes (31 SS, 10 SC, 4 S beta Thal) were compared with 61 age matched control patients for HCII in plasma. There was a highly significant reduction in HCII in SS patients irrespective of crisis or transfusion state 0.68 +/- 0.15 U/ml (mean +/- SD) compared with controls 1.00 +/- 0.19 U/ml (P < 0.001). HCII antigen was also significantly reduced (0.53 +/- 0.19 U/ml) compared with controls (1.02 +/- 0.23 U/ml, P < 0.0001). By contrast there was no reduction in antithrombin III in this group. HCII (0.63 +/- 0.13 U/ml, P < 0.001) and HCII antigen (0.54 +/- 0.08 U/ml, P < 0.001) are also significantly reduced in SC patients HCII levels increased towards control values during sickle cell crises, in patients taking the contraceptive pill, or with regular blood transfusion; however, plasma HCII concentrations were not increased acutely by exchange transfusion. HCII was also decreased in thalassaemia intermedia and pyruvate kinase deficiency, suggesting that intravascular haemolysis may be the cause of reduced HCII levels.

Adult↗
PubMed1993

Gonadal steroids have paradoxical effects on brain oxytocin receptors.

Specific brain receptors for oxytocin have been described in several mammalian species. The distribution of these receptors differs greatly across species and in the rat, receptor binding in specific brain regions appears to depend upon gonadal steroids. This study used in vitro receptor autoradiography to examine the effects of testosterone on oxytocin receptor binding in the mouse forebrain. Three groups of male mice were compared: castrates treated with blank capsules, castrates treated with testosterone filled capsules, and intact males. Irrespective of steroid treatment, the distribution of oxytocin receptors in mouse forebrain differed markedly from patterns previously described in the rat. In addition to these species differences in receptor distribution, testosterone had effects in the mouse which differed from the induction of receptors previously reported in the rat. In the mouse ventromedial nucleus of the hypothalamus, binding in the untreated castrate males was approximately double that observed in either the intact or the testosterone-treated castrates. In other regions of the mouse brain, such as the intermediate zone of the lateral septum, binding to oxytocin receptors was increased with testosterone treatment. These results suggest that the brain oxytocin receptor varies across species not only in its distribution but also in its regional regulation by gonadal steroids. These apparently paradoxical changes in oxytocin receptor binding may result from either direct or indirect effects of gonadal steroids in mouse brain.

Animals↗
PubMed1993

Antigen retrieval technique utilizing citrate buffer or urea solution for immunohistochemical demonstration of androgen receptor in formalin-fixed paraffin sections.

We developed a staining protocol for demonstration of androgen receptor (AR) in formalin-fixed, paraffin-embedded tissue sections. The method is based on the antigen retrieval microwave (MW) heating technique. Results are compared with different types of enzyme digestion pre-treatments. The strongest immunostaining signal and clearest background were obtained by MW heating of dewaxed paraffin sections in 5% urea or citrate buffer solution (pH 6); pure distilled water gave less consistent results. Enzymatic digestion with pepsin (0.05% in 2 N HCl) for 30 min at room temperature, or trypsin followed by pronase, or pronase digestion alone, also produced enhanced staining of AR in some cases, but there was more nonspecific background, and specific reactivity was less intense. The antigen retrieval MW method can be used to demonstrate AR epitope in prostate tissue after fixation in formalin for as long as 7 days. AR immunolocalization was also compared in frozen and paraffin sections processed from the same specimen of prostate carcinoma tissue and was found to be qualitatively and quantitatively similar. This study also provided new information concerning the basic principles of the antigen retrieval MW method that may be helpful in further development of this technique.

Antigens, Neoplasm↗
PubMed1993

Self-reported prevalence of asthma symptoms in children in Australia, England, Germany and New Zealand: an international comparison using the ISAAC protocol.

There is a need for a standardized approach to international and regional comparisons of the prevalence and severity of asthma, and for the monitoring of asthma morbidity over time. In 1991, standardized written and video questionnaires were developed and administered in surveys of schoolchildren, aged 12-15 yrs, in five regions in four countries: Adelaide, Australia (n = 1,428); Sydney, Australia (n = 1519); West Sussex, England (n = 2,097); Bochum, Germany (n = 1928); and Wellington, New Zealand (n = 1863). The self-reported prevalence of wheezing during the previous 12 months was similar in West Sussex (29% using the written questionnaire and 30% using the video questionnaire), Wellington (28 and 36%), Adelaide (29 and 37%), and Sydney (30 and 40%), but was lower in Bochum (20 and 27%). The one year prevalence of severe wheezing limiting speech was greater in Wellington (11%), Adelaide (10%) and Sydney (13%), than in West Sussex (7%) and Bochum (6%). The self-reported one year prevalences of frequent attacks, frequent nocturnal wheezing, and doctor diagnosed asthma, were also higher in the Australasian centres than in the European centres. We conclude, that an international comparison of asthma symptom prevalence in childhood, using simple standardized instruments, is feasible. Possible explanations for the differences in reported asthma severity between the Australasian and European centres include differences in exposure to risk factors and differences in the management of asthma.

Adolescent↗
PubMed1992

Iron deficiency.

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Child↗
PubMed1992

Sexual abuse and the problem of embodiment.

In this paper, trauma, sexual abuse, and some of the potential resulting long-term effects, are explored in terms of the problem of embodiment and the formation of personal identity and psychological integrity. That is, what effect does severe sexual abuse have on an individual's, particularly a child's, sense of living in his or her body and, by extension, living in the world? First, trauma and dissociation are analyzed and linked to the development and maintenance of a "posttraumatic" sense of personal identity. Then, several disorders associated with sexual abuse--dissociation, multiple personality disorder, eating disorders, somatization disorder, self-mutilation, suicide, and suicide attempts--are examined in terms of their phenomenological coherence and relation to the problem of embodiment. This conceptual framework may be of use to clinicians and researchers assessing and treating the survivors of sexual abuse.

Body Image↗