PARENTERAL THIAMINE AND WERNICKE'S ENCEPHALOPATHY: THE BALANCE OF RISKS AND PERCEPTION OF CONCERN

Wernicke's encephalopathy, a disorder with significant mortalityand high morbidity, is common amongst alcohol-dependent patients.Thiamine deficiency appears to play a key role in its aetiology,and parenteral high-dose thiamine is effective in prophylaxisand treatment. Unfortunately, reports of rare anaphylactoidreactions have led to a dramatic reduction in the use of parenteralthiamine, and it is possible that this change in treatment hasled, or will lead, to an increase in morbidity and mortality.There is a need for education of doctors who treat alcohol-dependentpatients, in order to ensure appropriate use of parenteral thiaminein prophylaxis and treatment of this disorder.     

Identifying target segments of male drinkers for health promotion

Data from a 1988 national drinking survey was cluster analysedto identify different types of male drinkers, to assist in thetargeting of health promotion strategies. Of the five segmentsgenerated by the clustering, one labelled Young Heavy DrinkingMales was identified as the most appropriate target segment,because although they were the segment reporting the highestlevel of alcohol-related problems they were also the segmentmost likely to feel they were drinking too much They were thereforethe segment most likely to be responsive to advertising thatsought to support people who wanted to change their drinkinghabits. They were also the most appropriate target for the longer-termgoal of changing the climate of opinion regarding the acceptabilityof more moderate drinking. Comparisons with two previous clusteranalyses showed a high degree of similarity, suggesting thatclustering is a reliable vehicle for identifying drinker types.     

Development and isotype diversity of antibodies to inhalant and dietary antigens in childhood atopic eczema

This study demonstrated that a major feature of childhood atopic eczema (AE) is the presence of serum IgG and IgE anti-house dust mite (anti-HDM) antibodies in almost all AE individuals. IgG anti-HDM antibodies, usually of the IgG1 isotype, became prevalent in AE children over the age of 4 years with the highest antibody levels in children in their early teens. In contrast, immunological sensitization to dietary antigens, notably milk and eggs, occurred in both AE children and age-matched non-atopic control children, and was often associated with IgG4 antibodies during early childhood. These became less prevalent with increasing age in control children but persisted in AE children, sometimes together with IgE antibodies. The later occurrence of anti-HDM antibodies in AE children could reflect immunological sensitization following inhalation of antigen, whereas sensitization to dietary antigens appears to be a natural event in early childhood.     

Agminate Spitz naevi arising on hyperpigmented patches

In 1948 Dr Sophie Spitz described criteria that distinguished juvenile melanoma from malignant melanoma.¹ Since then the cases of eruptive Spitz naevi have been reported arising on normal skin, on lightly pigmented patches and on hypopigmented patches. There are only 12 reports of Spitz naevi arising on hyperpigmented patches:^2-12 we describe here three further cases, all on the arms of children, seen in our department in a single year.     

EFFECT OF HIGH DOSE EXOGENOUS OESTROGEN ON MIDCYCLE LUTEINIZING HORMONE SURGE IN HUMAN SPONTANEOUS CYCLES

Induction of multiple follicular development in women results in supraphysiological serum oestradiol (E2) levels and marked reduction of the endogenous LH surge. To examine whether high serum E2 levels at midcycle can suppress gonadotrophin secretion during the LH surge, five normally ovulating women were given an intramuscular injection of 10 mg oestradiol benzoate 6-42 h before the expected endogenous LH surge. The results were compared with the preceding untreated control cycle. Serum E2 levels at the onset of the LH surge (mean +/- SEM) were significantly higher in the oestrogen-treated cycles (13,600 +/- 1963 pmol/l) than in the control cycles (1012 +/- 116 pmol/l) (P less than 0.001). The duration of the LH surge (64.8 +/- 2.2 h) and LH peak levels (136 +/- 9.6 mIU/ml) in the oestrogen treated cycles were similar to those in the control cycles (61.2 +/- 3.9 and 119 +/- 9.4 mIU/ml respectively) (mean +/- SEM). The cycle day on which the LH surge started and the size of the dominant follicle, as assessed by ultrasound, did not differ significantly between the two groups of cycles. These results show that in spontaneous cycles the endogenous LH surge is neither reduced nor amplified by the induction of supraphysiological serum E2 levels during the immediate pre-ovulatory stage.     

ETHANOL ENHANCES MEDIAL AMYGDALOID INDUCED INHIBITION OF PREDATORY ATTACK BEHAVIOUR IN THE CAT: ROLE OF GABAA RECEPTORS IN THE LATERAL HYPOTHALAMUS

The present study tested the hypothesis that the suppressiveeffects of ethanol upon predatory attack behaviour in the catinvolve a pathway from the medial amygdala to the lateral hypothalamus,and that these suppressive effects are mediated by -aminobutyricacid (GABA_A receptors located in the lateral hypothalamus. Cannulaelectrodes were implanted into the lateral hypothalamus forelicitation of predatory attack behaviour and for microinjectionsof the GABA_A receptor antagonist, bicuculline. Monopolar stimulatingelectrodes were implanted into the medial amygdala from whichsubseizure levels of electrical stimulation suppressed predatoryattack behaviour. In the first phase of the study, we comparedresponse latencies for predatory attack behaviour followingsingle stimulation of the lateral hypothalamus alone with thosefollowing paired trials of dual stimulation of the medial amygdalaplus lateral hypothalamus. Dual stimulation significantly suppressedpredatory attack. In the second phase of the study, peripheralethanol administration (in doses of 0.01, 0.5 and 1.0 g/kg,i.p.) enhanced the suppressive effects of medial amygdaloidstimulation in a dose- and time-dependent manner in which peakeffects were obtained 60 min post-injection. In the third phaseof the study, bicuculline (0.15 nmol) was microinjected intothe lateral hypothalamus both prior to and following pairedtrials of dual stimulation. Drug infusion blocked the suppressiveeffects of medial amygdaloid stimulation upon predatory attackbehaviour elicited from the lateral hypothalamus, indicatingthe importance of GABA_A receptors in mediating this suppression.In the fourth phase of the study, bicuculline, microinjectedinto the lateral hypothalamus at the time when ethanol's effectswere maximal (i.e. 60–80 min post-ethanol administration),totally blocked the suppressive effects of medial amygdaloidstimulation as well as the enhancing effects of ethanol uponmedial amygdaloid suppression of this form of aggressive behaviour.In the last phase of the study, bicuculline (0.15 nmol) infusioninto the lateral hypothalamus significantly reduced the suppressiveeffects of ethanol (10g/kg, i.p.) upon predatory attack behaviourelicited from the lateral hypothalamus. These results supportthe hypothesis that ethanol's suppressive effects upon predatoryattack behaviour in the cat are mediated, at least in part,by GABA_A receptors in the lateral hypothalamus. The presentand recent findings in our laboratory support the view thatGABA_A receptors in the lateral hypothalamus are activated, inturn, by a GABAergic pathway which arises from the medial hypothalamuswhose neurons receive inputs from the medial amygdala.     

NON-SPECIFIC SUPERSENSITVITY IN RAT PAROTID SALIVARY GLANDS FOLLOWING PARASYMPATHECTOMY

• 1 The effect of parasympathetic denervation (Px) of the rat parotid salivary glands has been studied.
• 2 Px produced a significant reduction in wet and dry weight of the parotid gland compared with the intact contralateral control gland. The DNA content per gland was not reduced indicating that cell death had not occurred but that individual cells were smaller.
• 3 Supersensitivity to both cholinoreceptor and β-adrenoreceptor stimulation resulted following Px and was observed as a decrease in the threshold dose and an increase in the maximum secretory response.
• 4 The supersensitivity to β-adrenoreceptor stimulation was not accompanied by a change in cyclic AMP production but there was an increase in the density of β-adrenoreceptor binding sites/mg membrane protein.
• 5 The relationship of this increased density of receptors to the observed supersensitivity is discussed.