The effects of methylglyoxal on central synaptic transmission in the isolated nerve cord of the cockroach. (Periplaneta americana L)

Methylglyoxal (10(-5) to 1.5 X 10(-4) M) was found to have excitatory effects on synaptic transmission in the isolated 6th abdominal ganglion of the cockroach. There was a concentration-dependent depolarization of the giant interneurones which was accompanied by an increase in the amplitude and duration of electrically evoked excitatory postsynaptic potentials. The frequency of spontaneous activity was also increased.

Histamine receptors in human skin: indirect evidence

Use of differential effects of agonists and antagonists has provided an experimental basis for subdivision of histamine receptors into H1 and H2. This has enabled classification of the responses to histamine in a wide range of organs and tissues. In human skin the vascular and sensory effects of histamine have been studied, and the influence of histamine on epidermal cell growth has been evaluated in vitro. The direct vasodilator and vascular permeability actions of histamine appear to involve both H1 and H2 receptors. However, the axon reflex flare due to histamine appears to be predominantly an H1 effect. Histamine itch involves H1 receptors. These findings have prompted clinical evaluation of combined therapy with H1 and H2 antagonists in patients with urticaria. Initial results have been encouraging in patients with factitious urticaria. Histamine exerts an inhibitory action on epidermopoiesis in vitro in a number of mammalian epidermal cell outgrowth systems including human explants. The pathophysiological relevance of this effect, which involves epidermal H2 receptors and which may be cyclic AMP dependent, is unknown.

Failure to demonstrate fibrotic changes in the skin of mice injected with glycosaminoglycan fractions from the urine of scleroderma patients

Glycosaminoglycan (GAG) fractions isolated from the urine of scleroderma patients were compared with GAGs from control subjects for their ability to induce fibrotic changes in the skin of mice after intraperitoneal injection. Contrary to previous reports, however, no fibrotic changes were detectable, either visibly or in terms of skin tissue thickness. The ability to obtain consistently authentic biologically active factors from this source is therefore questioned.

Combining psychometric data on brain damage and the influence of aging

60 young and middle-aged patients (age 20 to 52 yr.) with generalized and chronic brain damage were individually matched for age, social class, education, and occupational history with normal control subjects with no history of brain damage. Both groups were given a battery of cognitive tests which included Clément's Digit Code test, Memory-for-Designs, Trail Making, the Spiral Aftereffect, Elithorn's mazes, Mill Hill vocabulary, Progressive Matrices, and the Synonym test. The discriminative efficiency of each measure was examined individually and in combination using discriminant function analysis. The most efficient individual discriminator was the Digit Code. When this was combined with the Trail Making Part B, correct over-all classification was 80%. No other addition improved discrimination significantly. Thus a battery of tests taking 10 min. to administer was as effective as the larger battery which took more than 2 hr. The gradient of test scores with age was examined cross-sectionally for each measure. For most tests, gradients were larger for the brain-damaged than for the control group.

Nevus oligemicus. A variant of nevus anemicus

A man had a long history of a persistent, fixed area of livid erythema on the trunk. The distribution of hair, sweat, and sensation were normal as were the histologic findings in the affected skin. The involved area had a decreased total skin blood flow and a lower surface temperature compared with surrounding uninvolved skin, but showed normal responses to vasoconstrictor and vasodilator stimuli. Incomplete sympathetic blockade partially abolished the erythema. We suggest that the appearance of the nevus is caused by increased vasoconstrictor tone in the thermoregulatory vessels of the involved skin, leading to relative stasis in the superficial "nutritional" vasculature. This would seem to be a new example of a "pharmacological nevus" showing similarities to and differences from nevus anemicus.

Sensory responses of human skin to synthetic histamine analogues and histamine

The potential for itch production in human skin of the synthetic analogues of histamine, 2-methyl histamine (an H1-receptor agonist) and 4-methyl histamine and dimaprit (H2-receptor agonists) has been studied in vivo and compared with histamine. Itch thresholds for 2-methyl histamine were consistently much higher than for histamine (P < 0.001). The H1-receptor antagonist chlorpheniramine raised the itch thresholds to 2-methyl histamine and histamine significantly (P < 0.001). Pruritus was not obtained with either 4-methyl histamine or dimaprit. No evidence of synergism between 2-methyl histamine and either 4-methyl histamine or dimaprit was found. The results suggest that histamine-induced pruritus is mediated in part through the H1-receptor and in part via an additional (but probably non-H2) mechanism.

Pyoderma gangrenosum: clinical and laboratory findings in 15 patients with special reference to polyarthritis

Fifteen consecutive patients with PG have been studied during the period 1971-78. Systemic disease was found in 13 of the patients and preceded the skin disease in 10 patients by 1-25 years. Only two patients had ulcerative colitis. One patient had paroxysmal nocturnal hemoglobinuria and three patients had an IgA myeloma. Eight patients had polyarthritis; this was classical seropositive rheumatoid arthritis in two patients, and a seronegative inflammatory polyarthritis in six patients. Four patients had an unusual progressive erosive seronegative polyarthritis without evidence of granulomatous bowel disease, psoriasis, genital, urinary tract or eye disease. In three of these four patients the arthritis preceded the PG. Synovial fluid analysis showed depressed complement levels and in one patient deposits of immunoglobulins and complement were demonstrated in the synovial membrane. The course of the arthritis was progressive with development of disabling joint deformities and erosive destruction of joints, despite treatment with penicillamine, corticosteroids and nonsteroidal anti-inflammatory drugs. One other patient had severe degenerative joint disease and chondrocalcinosis in association with a seronegative inflammatory polyarthritis, and another patient had ulcerative proctitis and severe degenerative joint disease secondary to chronic seronegative inflammatory polyarthritis. None of the patients had colitic arthritis, but in view of the association between PG and ulcerative colitis, some patients previously reported with PG and joint disease may have been suffering from the arthritis of ulcerative colitis. PG developed at the site of skin trauma in six patients. The natural history of the skin disease ran one of two courses: an acute, progressive course in which the ulcers rapidly enlarged until arrested by treatment; and a chronic course in which the lesions extended slowly and which after a period of weeks began to show signs of spontaneous healing. In only the patients with ulcerative colitis was there any correlation between the activity of the associated disease and the onset and progression of the skin disease. Serum complement levels were normal and no circulating cryoprecipitable immune complexes were found. Skin histology showed no evidence of vasculitis and direct immunofluorescence examination of involved skin was negative for IgG, IgM, IgA and C3. No consistent abnormality of cell-mediated immunity or neutrophil function was found and no significantly increased prevalence of any HLA antigen type was noted. Twelve patients have been treated with systemic corticosteroids. Six of these patients developed serious steroid complications and four patients have died, all from complications of steroid therapy.

The abnormal dermis in pyogenic granuloma. Histochemical and ultrastructural observations

The connective and vascular tissues of pyogenic granulomas have been studied in lesions from forty-six patients. Twenty were studied histochemically, and five were examined ultrastructurally. Both tissues showed a wide range of maturity and cellular activity. The fibroblasts in particular showed evidence of increased synthetic activity. Intranuclear inclusion bodies, suggestive of altered synthetic activity, were found in the endothelial cells of four lesions. It is suggested that pyogenic granuloma arises from disordered growth of papillary dermis.

The efficacy of histamine antagonists as antipruritics in experimentally induced pruritus

1. The antipruritic ability of histamine (H1 and H2) antagonists alone and in combination in experimentally induced pruritus has been investigated in 12 normal human volunteers. 2. A combination of cimetidine (H2 anatagonist) and chlorpheniramine (H1 antagonist) proved effective in suppressing itch that was artificially induced by the application of papain and histamine. 3. The combination was more effective than chlorpheniramine or cimetidine alone or placebo. 4. The results suggest that both H1 and H2 receptors are involved in the mediation of pruritus.

Atopic disease and dermatitis herpetiformis

Patients with dermatitis herpetiformis were found to have an increased incidence of atopic disorders compared to an age and sex matched control group. The increase in incidence was statistically significant for atopic eczema and any atopic disorder. Serum immunoglobulins (including IgE) were estimated in forty-five dermatitis herpetiformis patients and no significant abnormalities were found.