Review: The Actions and Side Effects of β-adrenoceptor Blocking Drugs

ABSTRACT This review presents information on the autonomic nervous system, with particular reference to the noradrenergic sympathetic nervous system and adrenoceptors. This leads on to a discussion of the mechanism of action of, main effects and side effects of, and contraindications to the use of the β-adrenoceptor blocking drugs. Emphasis is given to the use of timolol eye drops in the treatment of glaucoma and some consideration is given to its possible mechanism of action in the eye. The review is based on a lecture presented to the 4th Australian/International Optometrical Congress, Gold Coast, Queensland, October 1982.     

Play materials and toys in the education of young children

Woodroffe, Stella E. and Willatt, Beverley J. (1976). Aust. paediat. J., 12, 1–5. Play materials and toys in the education of young children. The paper discusses the need to consider the developmental level of the child when selecting appropriate toys and play materials that serve an educational purpose. The relevance of a number of play materials is discussed in general terms, although a range of possibilities for particular types of learning are specified in relation to some toys.
The learning is not inherent in the material but depends on the child's own cognitive processes, often assisted by an adult who is in a position to draw the child's attention to particular aspects of his encounters with his environment, and to guide the direction of his learning. For young children, a wide range of experiences will serve as a base upon which he will build his own structures. These will enable him to adapt to the requirements of learning his society will impose upon him as he grows.
Criteria are suggested for selecting toys and play materials which can serve an educative end. The reader is also reminded that materials which serve the child best are those which offer him a range of possibilities. Many of these are readily available in the home or neighbourhood and do not entail spending large sums of money, provided one uses a little imagination.     

Liposoluble vitamins and naturally occurring carotenoids in porphyria cutanea tarda

Abstract. The authors consider two groups of patients with overt sporadic porphyria cutanea tarda (PCT) from different continents, with the aim of evaluating the possible impairment of the liposoluble antioxida-tive system, given the possible synergic effect of porphyrins and iron in promoting oxidative cellular damage. Twenty-three Italian outpatients with overt sporadic PCT and 11 outpatients with PCT from Buenos Aires (Argentina) were matched with 60 patients with liver cirrhosis and 52 healthy Italian controls. Serum levels of alpha- and beta-carotene, cryptoxanthin, zeaxanthin, lutein, lycopene, retinol and alpha-tocopherol were detected by a high-performance liquid chromatographic technique devised in our laboratory, which afforded an accurate and simultaneous resolution of all these compounds. The results point to a significant reduction in plasma levels of alpha- and beta-carotene in both the PCT populations with respect not only to controls, but also to the cirrhotic population, which had more severe liver damage. Moreover, other carotenoids with proven antioxidative properties, like cryptoxanthin and lycopene, are greatly reduced in our PCT populations. This confirms the suggested synergic effect of iron and porphyrins in the oxidative intracellular damage with consequent depletion of antioxidative liposoluble molecules.     

EFFECT OF NALOXONE ON THE LOSS OF CONSCIOUSNESS INDUCED BY I.V. ANAESTHETIC AGENTS IN MAN

The effect of a specific opioid antagonist, naloxone, was studiedin two comparable groups of patients who received i.v. the doseof an anaesthetic agent required to produce loss of consciousnessin 50% of subjects. The first group received naloxone 0.006mg kg^–1 5 min before induction of anaesthesia; the secondgroup received a similar volume of saline solution. Thiopentone,Althesin, diazepam, ketamine and propanidid were studied. Thedifferences in percentage of unconscious patients between thenaloxone-treated group and the control group were statisticallysignificant for diazepam, ketamine and propanidid. Naloxonedid not modify the induction of anaesthesia with thiopentoneor Althesin     

PROTECTIVE ROLE OF ENALAPRIL FOR CHRONIC TUBULOINTERSTITIAL LESIONS OF HYPEROXALURIA

PURPOSE: Hyperoxaluria is a recognized cause of tubulointerstitial lesions and it may contribute to chronic renal failure. In previous studies we demonstrated that enalapril was effective against the progression of tubulointerstitial lesions in a 4-week hyperoxaluria rat model. We evaluated whether the action of enalapril on the tubulointerstitial lesions produced by hyperoxaluria persisted for a long period. MATERIALS AND METHODS: Two-month-old male Sprague-Dawley rats were divided into 4 groups of 12 each, including 1--control animals given tap water, 2--animals with hyperoxaluria, 3--animals with hyperoxaluria plus enalapril, 4--animals with enalapril. Hyperoxaluria in groups 2 and 3 rats was induced by administering 1% ethylene glycol, a precursor for oxalates, in the tap water continuously throughout the whole study. Meanwhile, groups 3 and 4 received 20 mg./l. enalapril in the drinking water. At the end of the study renal tubulointerstitial lesions were evaluated by immunostaining using monoclonal antibodies against macrophage infiltrates (ED1), tubulointerstitial alpha-smooth muscle actin and transforming growth factor-beta1. The lesions were quantified by semiquantitative scores. Creatinine clearance and urinary albumin excretion were also determined. RESULTS: There was no difference in urine oxalate excretion in groups 2 and 3. Group 3 rats treated with enalapril showed fewer tubulointerstitial lesions than nontreated group 2 rats, as indicated by the mean scores plus or minus standard error of mean for inflammatory infiltrate (2.16 +/- 0.2 versus 0.83 +/- 0.16), tubular atrophy (2 +/- 0.27 versus 0.66 +/- 0.14), interstitial fibrosis (2.5 +/- 0.15 versus 0.5 +/- 0.1), glomerular ED1 (1.75 +/- 0.25 versus 0.16 +/- 0.11), interstitial ED1 (2.33 +/- 0.18 versus 0.58 +/- 0.10) tubular transforming growth factor-beta1 (2.09 +/- 0.08 versus 0.91 +/- 0.14), interstitial transforming growth factor-beta 1 (2.33 +/- 0.22 versus 0.66 +/- 0.12), tubulointerstitial alpha-smooth muscle actin (2.91 +/- 0.22 versus 0.83 +/- 0.16), lower urinary albumin excretion (35.5 +/- 2.7 mg. daily versus 10.9 +/- 1) and higher creatinine clearance (2.29 +/- 0.04 ml. per minute versus 2.54 +/- 0.03, all p <0.05). CONCLUSIONS: Based on our results we believe that enalapril would provide a beneficial effect against chronic tubulointerstitial lesions caused by oxalates.     

Retention in methadone maintenance and heroin addicts'risk of death

A long-term follow-up was made of a cohort of 307 heroin addicts admitted into a high-dose, Australian methadone maintenance programme in the early 1970s. Using data from clinic records, official death records and methadone treatment histories, it was found that subjects were nearly three times as likely to die outside of methadone maintenance as in it (95% CI RR 1.45 to 5.61). Data were further analyzed using Cox regression to investigate the association of maximum daily methadone dose and a change in clinic policy with retention in maintenance treatment. It is estimated that subjects given a maximum daily dose of 80 mg were nearly twice as likely to be discharged during the first three years of maintenance as those given 120 mg (95% CI RR 1.3 to 2.2). The estimated median time in maintenance for subjects given a maximum dose of 120 mg mas 1150 days while for 80 mg it was 660 days. It is further estimated that the change in clime policy from abstinence to indefinite maintenance reduced to one-third subjects’risk of leaving after three years’of treatment (95% CI RR 0.19 to 0.54). It is concluded that, in order to minimise heroin addicts’risk of death, they should be offered indefinite, high-dose methadone maintenance.     

Obstacles to Nutrition Labeling in Restaurants

Objective This study determined the major obstacles that foodservices face regarding nutrition labeling.Design Survey questionnaire was conducted in May 1994. In addition to demographic questions, the directors were asked questions addressing willingness, current practices, and perceived obstacles related to nutrition labeling.Subjects/setting Sixty-eight research and development directors of the largest foodservice corporations as shown in Restaurants &. Institutions magazine's list of the top 400 largest foodservices (July 1993).Statistical analyses performed P tests were used to determine significance within a group for the number of foodservices that were currently using nutrition labeling, perceived impact of nutrition labeling on sales, and perceived responsibility to add nutrition labels. Regression analysis was used to determine the importance of factors on willingness to label.Results Response rate was 45.3%. Most companies were neutral about their willingness to use nutrition labeling. Two thirds of the respondents were not currently using nutrition labels. Only one third thought that it was the foodservice's responsibility to provide such information. Several companies perceived that nutrition labeling would have a potentially negative effect on annual sales volume. Major obstacles were identified as menu or personnel related, rather than cost related. Menu-related obstacles included too many menu variations, limited space on the menu for labeling, and loss of flexibility in changing the menu. Personnel-related obstacles included difficulty in training employees to implement nutrition labeling, and not enough time for foodservice personnel to implement nutrition labeling.Applications Numerous opportunities will be created for dietetics professionals in helping foodservices overcome these menu- or personnel-related obstacles. J Am Diet Assoc. 1997; 97:157–161.     

A comparison of the binding constant (Kd) of 125I-labelled 3-(4-iodophenoxy)-1-isopropylamino-propan-2-ol obtained on β-adrenoceptors in guinea-pig myocardial membranes,with its dissociation constants (Kb) obtained on guinea-pig isolated atria and trachea

The dissociation constant of binding (K_D) of ¹²⁵I-labelled 3-(4-iodophenoxy)-1-isopropyl-aminopropan-2-ol (IIP) to guinea-pig myocardial membrane preparations was 2·2 × 10^?8m. In pharmacological experiments with the non-labelled material and 60 min contact time, IIP produced a parallel shift in the orciprenaline concentration-response line on guinea-pig isolated tracheal and atrial preparations. The dissociation constant (Kb ) of IIP was 2·9 × 10^?8m on atria (pA₂ 7·54) and 3·3 × 10^?8m on trachea (pA₂ 7·48). These values indicate that IIP is not a selective β-adrenoceptor blocking drug. In addition, agreement was found between the affinity constant of this antagonist for β-adrenoceptors as determined by a direct binding study and an indirect pharmacological study.