AC/A ratios in myopic and emmetropic Hong Kong children and the effect of timolol§

Purpose: Caucasian children with myopia have elevated response accommodative vergence to accommodation (AC/A) ratios. The purpose of this study was twofold: to determine if response AC/A ratios vary with refractive error and with myopic progression rate in Hong Kong Chinese children, and to determine the effect of beta‐adrenergic antagonism with topical timolol application on AC/A ratios. Methods: Thirty children aged eight to 12 years participated in the study. All refractive errors were corrected with spectacle lenses. Accommodative responses were measured using a Shin‐Nippon autorefractor and concurrent changes in vergence were assessed using a vertical prism and a Howell‐Dwyer card at three metres and 0.33 metre. Accommodative demand was altered using plus or minus two dioptre lenses and lens‐ and distance‐induced response AC/A ratios were calculated. Measurements were repeated 30 minutes after the instillation of topical timolol maleate (0.5 per cent). Results: AC/A ratios appeared higher in progressing myopic children but the difference was not statistically significant. Timolol application reduced accommodative convergence (AC) in the stable myopes (reduction = ‐3 ± 1.14^A) but not in the emmetropes (0.69 ± 0.9^P) or progressing myopes (0.16 ± 0.43^A) and this difference between refractive groups was statistically s ignificant (F^2,27= 3.766; P= 0.036). However, timolol did not produce a significant change in the accommodative response to positive or negative lenses or response AC/A ratios. Conclusions: We did not find that AC/A ratios in myopic Chinese children were elevated and therefore, it is unlikely that elevated AC/A ratios are responsible for the high levels of myopia that occur in Hong Kong. The finding that timolol reduced AC in the stable myopes suggests that the autonomic control of accommodative convergence in these children may be different from that in emmetropic children and those with progressing myopia.     

Activation of guinea pig eosinophil respiratory burst by leukotriene B4: role of protein kinase C

Leukotriene B4 (LTB4) and the protein kinase C activator, 4-beta-phorbol dibutyrate (PDBu), both induced a pronounced and concentration-dependent stimulation of hydrogen peroxide (H2O2) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM-1 microM. The LTB4 response was inhibited competitively by the specific LTB4 receptor antagonist, U-75302, with a KB of 25 nM, while the concentration-response curves for both stimuli were shifted rightwards (3.8-fold and 2.8-fold for LTB4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1-O-hexadecyl-2-O-methylglycerol at a concentration of 300 microM. LTB4 appears, therefore, to induce respiratory burst in eosinophils via a receptor-mediated mechanism involving protein kinase C.     

Acute health effects of the Sea Empress oil spill

STUDY OBJECTIVE: To investigate whether residents in the vicinity of the Sea Empress tanker spill suffered an increase in self reported physical and psychological symptoms, which might be attributable to exposure to crude oil. DESIGN: Retrospective cohort study; postal questionnaire including demographic details, a symptom checklist, beliefs about health effects of oil and the Hospital Anxiety and Depression and SF-36 mental health scales. SETTING: Populations living in four coastal towns on the exposed south Pembrokeshire coast and two control towns on the unexposed north coast. PATIENTS: 539 exposed and 550 unexposed people sampled at random from the family health services authority age-sex register who completed questionnaires. MAIN RESULTS: Adjusted odds ratios for self reported physical symptoms; scores on the Hospital Anxiety and Depression and SF-36 mental health scales, in 1089 people who responded out of a possible 1585 (69%). CONCLUSIONS: Living in areas exposed to the crude oil spillage was significantly associated with higher anxiety and depression scores, worse mental health; and self reported headache (odds ratio = 2.35, 95% CI 1.56, 3.55), sore eyes (odds ratio = 1.96, 95% CI 1.06, 3.62), and sore throat (odds ratio = 1.70, 95% CI 1.12, 2.60) after adjusting for age, sex, smoking status, anxiety, and the belief that oil had affected health. People living in exposed areas reported higher rates of physical and psychological symptoms than control areas. Symptoms significantly associated with exposure after adjustment for anxiety and health beliefs were those expected from the known toxicological effect of oil, suggesting a direct health effect on the exposed population.     

Modification of 5-HT2 receptor mediated behaviour in the rat by oleamide and the role of cannabinoid receptors

Oleamide (cis-9,10-octadecenoamide) is an endogenous brain lipid which has been suggested to induce sleep in experimental animals. The mechanism of action is unclear but shares many of the characteristics of endogenous cannabinoids such as anandamide and has been shown to enhance in vitro responses to 5-HT and GABA. In the present study we investigated the effects of oleamide on two motor behaviours, back muscle contractions (BMC) and wet-dog shakes (WDS) induced in rats by treatment with the 5-HT2 receptor agonist DOI ((+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride). We then examined the potential involvement of CB1 cannabinoid receptors in the responses to oleamide and the mechanism of interaction between CB1 and 5-HT2 receptors. Oleamide and the cannabinoid receptor agonist HU210 (6aR)-trans-3-(1,1-dimethylheptyl)6a,7,10,10a-tetrahydro-1-h ydroxy-6,6-dimethyl-6H-dibenzo[b,d]pyran-9-methanol) produced a hypolocomotion which was prevented by the CB1 antagonist SR141716A (N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-me thyl-1H-pyrazole-3-carboxamide hydrochloride). Despite having no effect alone, oleamide and HU210 potentiated BMC induced by treatment with DOI. SR141716A alone did not affect the response to DOI but it blocked the potentiations caused by oleamide or HU210. WDS were unaffected by oleamide and slightly reduced by HU210. In vitro, oleamide and HU210 enhanced the high affinity binding of 5-HT to 5-HT2 receptors on rat cerebral cortex membranes labelled with 3H-ketanserin. Neither agent, however, altered 5-HT-stimulated phosphoinositide hydrolysis in rat cerebral cortex slices. Oleamide occupied CB1 cannabinoid receptors on rat brain membranes labelled with 3H-CP55940 with an IC50 of 10 microM. The data presented are consistent with oleamide acting via a cannabinoid recognition site to enhance 5-HT2 receptor function in vivo. The mechanism of the modulation is still unclear but it does not appear to involve a potentiation of 5-HT2 receptor-stimulated phosphoinositide hydrolysis.     

Characterization of the procoagulant chain derived from human high molecular weight kininogen (Fitzgerald factor) by human tissue kallikrein

Human high molecular weight kininogen (HMWK), a single-chain protein with mol wt 120,000, is cleaved by human urinary kallikrein (HUK) to release kinin from within a disulfide loop and form a two-chain protein that retains all the procoagulant activity of the native molecule. Cleavage of HMWK by HUK is associated with a reduction in size to mol wt 115,000, as assessed by SDS-PAGE of unreduced protein, whereas the two chains of the reduced protein present together as a single broad band with mol wt 64,000. The 64,000 chain with procoagulant activity was chromatographically separated from the nonfunctional chain of similar size. The homogeneous procoagulant chain had an amino acid composition similar to that of smaller procoagulant ("light") chains isolated by others upon cleavage of HMWK with plasma kallikrein and elicited an antiserum that was monospecific by Ouchterlony analysis and inhibited the procoagulant function of HMWK. Thus, the limited proteolysis of HMWK by HUK has permitted, for the first time, the isolation of a stable procoagulant chain that is equal in size to the nonfunctional chain. The common terminology of "heavy" and "light" chain for kinin-free kininogen obtained with plasma kallikrein reflects the continued degradation of the procoagulant carboxyterminal chain and is not appropriate for the initial two-chain product formed when kinin is released from HMWK. It is proposed that the initial cleavage products of HMWK be designated the A-chain, the B-fragment, and the C- chain, representing the amino-terminal chain, the released vasoactive peptide containing the bradykinin sequence, and the carboxy-terminal procoagulant chain, respectively. Thus, intact HMWK would contain, in sequence, A, B, and C regions.     

Fatal Hepatic Coma Complicating Oxymetholone Therapy in Multiple Myeloma

Fatal hepatic coma complicating oxymetholone therapy in multiple myeloma. G. P. Young, P. S. Bhathal, J. R. Sullivan, A. J. Wall, D. J. Fone and T. H. Hurley, Aust. N.Z. J. Med, 1977,7, pp. 47–51. Two patients with multiple myeloma died in acute liver failure. Both had been treated with the anabolic steroid oxymetholone and both subsequently developed severe cholestatic hepatitis. In one the histological lesion progressed despite cessation of oxymetholone therapy. Myeloma infiltration of the liver and peliosis hepatis were not seen. As a fatal outcome from cholestatic hepatitis due to oxymetholone is rare it is possible that an unknown potentiating factor is present in multiple myeloma that can lead to a fatal outcome. If oxymetholone therapy is to be used in such patients then close clinical and laboratory assessment of liver function should be carried out in an attempt to prevent this unusual and fatal complication.     

Wound infection,dressings and pain,is there a relationship in the chronic wound?

The focus on quality of life issues in wound care has justly taken a far greater importance. With the acceptance that pain can be a major factor to the patient, and in particular, pain at dressing change comes the opportunity for avoidance and/or reduction strategies. Whilst pain has been associated with wound infection for millennia, it is only much more recently that this has received due attention from research and clinical practice. In this study, the nature of pain, changes in pain and pain associated with infection are the focal points. A Delphi approach, now a frequently used tool in wound care research, has been used to obtain expert opinion on these aspects of management.