Following a tolerance study, double-blind placebo controlled trials were conducted to determine the prophylactic effect of zinc gluconate lozenges on rhinovirus challenge and, in a third study, their therapeutic efficacy when given at the start of colds caused by virus inoculation was tested. In the prophylaxis study a total of 57 volunteers received lozenges of either zinc gluconate (23 mg) (29 volunteers) or matched placebo (28 volunteers) every 2 h while awake during a period of four and a half days. They were challenged with 10(2) tissue culture infecting dose (TCID50) of human rhinovirus 2 (HRV-2) on the second day of medication, and were monitored daily for symptoms and signs of colds and laboratory evidence of infection. Zinc reduced the total mean clinical score from 8.2 in the placebo group to 5.7 and the reduction of the mean clinical score was statistically significant on the second day after virus challenge. In the therapeutic study 69 volunteers were inoculated with 10(2) TCID50 of HRV-2 and those who developed cold symptoms were randomly allocated to receive either zinc gluconate lozenges (six volunteers) or matched placebo lozenges (six volunteers) every two hours they were awake for six days. Treatment of colds with zinc reduced the mean daily clinical score and this was statistically significant on the fourth and fifth day of medication. Similarly, medication also reduced the mean daily nasal secretion weight and total tissue count and these reductions were statistically significant on days two and six for nasal secretion weights and days four to six of medication for tissue counts when compared with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

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To determine whether the improvement in clinical status of patients with active acromegaly correlates with a reduction of circulating somatomedin-C, serum immunoreactive somatomedin-C was measured in twenty-seven patients before and during bromocriptine therapy. The patients were assessed using a clinical and metabolic score which included both subjective criteria of improved sweating and facial features, and objective criteria of a reduction in ring circumference and the area under the glucose tolerance curve. Using this, together with the change in GH levels before and during bromocriptine therapy, the patients could be divided into three groups. In one group, there was no clinical improvement, a less than 30% decline in somatomedin-C, and in four of six patients no significant decline in GH. In both the other groups there was clinical improvement and a greater than 30% decrease in somatomedin-C. In one of these two groups, however GH did not decline, while in the other it was reduced significantly. The results suggest that during bromocriptine treatment of acromegaly, serum somatomedin-C concentrations correlate better with clinical status that does serum GH. Since some patients have no significant fall in GH but show both clinical improvement and a reduction in somatomedin-C, it seems likely that in some patients bromocriptine may improve acromegaly by a mechanism other than a simple decrease in total immunoreactive GH secretion.

Twenty-four adult volunteers were inoculated with nasal drops containing a coronavirus of 229E serotype to determine the differences in the clinical and physiological reactions which occur between clinically infected, sub-clinically infected and non-infected individuals. Thirteen volunteers were clinically infected, 8 had sub-clinical infections and 3 were uninfected. Nasal airway resistance and the temperature of the nasal mucosa increased in all infected subjects both with and without symptoms: the core temperature increased also but to a lesser extent. Mucosal blood flow and nasal secretion increased only in those with symptoms. The albumin content of the nasal secretion increased in the clinically infected, suggesting that it was derived, partially at least, from the circulation. The nasal cycle of variation in airway resistance between the two sides of the nose was observed in all three groups but increased only in those clinically infected.

Two studies are reported on the effects of drugs on the performance impairments induced by experimentally- produced colds. The first study examined the effects of zinc gluconate on choice reaction time, and showed that the zinc removed the cold-induced performance impairment. The second experiment used nedocromil sodium and, again, the drug was effective in reducing the drop in performance observed in volunteers with colds. While the precise mode of action of these compounds is unclear it is speculated that one mechanism involves changes in trigeminal stimulation, and this could be responsible for both the clinical efficacy and CNS effects of these drugs.