The fine structure of the epidermis of two species of salmonid fish, the Atlantic salmon (Salmo salar l.) and the brown trout (Salmo trutta L.). I. General organization and filament-containing cells

The fine structure of the epidermis or two species of salmonid fish has been described. Gross characteristics have been noted along with many apparent differences in the epidermis of different body regions of the fish. The major cell type is the filament-containing cell and this has been described in detail. The major inclusions of the cell are the tonofilaments. Differences in basal, mid-epidermal and periphal filament-c0ntaingcells have been characterized. Comparisons of fish epidermis with that of other vertebrates has been made.

Acrodermatitis enteropathica. Corneal involvement with histochemical and electron micrographic studies

A case of acrodermatitis enteropathica occurred with corneal changes consisting of linear subepithelial corneal opacities. From the results of histochemical and electronmicrographic studies on a biopsy specimen of the corneal lesion, no definite conclusion may be drawn as to whether the corneal changes are a manifestation of acrodermatitis enterophathica or a result of iodochlorhydroxyquin therapy.

Activation by cyclic 3':5'-adenosine monophosphate of tyrosine hydroxylase in the rat brain

Membrane-permeable derivatives of cyclic AMP (cAMP) produced concentration-dependent increases in activity of tyrosine hydroxylase (L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2) in membrane-limited nerve endings (synaptosomes) prepared from three regions of rat brain. Increased hydroxylation occurred even after preincubation and removal of dibutyryl cyclic AMP. In all brain regions, the hydroxylation of phenylalanine and tyrosine was increased, but dibutyryl cAMP had little effect on activity of tryptophan hydroxylase, no effect on aromatic amino-acid decarboxylase, on uptake of tyrosine or phenylalanine, uptake or efflux of dopamine, or distribution of hydroxylase between cytoplasmic and particulate components of the synaptosomes. Dibutyryl cAMP decreased inhibition of catecholamine synthesis in synaptosomes by dopamine and apomorphine. In a soluble preparation of striatal tyrosine hydroxylase, activity was increased by addition of lower concentrations of cAMP or dibutyryl cAMP than with unbroken nerve endings, when subsaturating concentrations of tyrosine and cofactor were employed, while butyrate, chloride, 5'-AMP, ADP, ATP, and cyclic GMP had no activating effect. Increased activity of soluble tyrosine hydroxylase was reflected in increased affinity (Km) for substrate and cofactor and decreased affinity (Ki) for inhibitory end-product (dopamine), suggesting a change in the physical-chemical state of the enzyme or an activator molecule. Cyclic AMP may activate tyrosine hydroxylase during periods of increased neuronal activity.

Beneficial effect of hemodialysis on renal allograft survival

The effect of the length of hemodialysis on the outcome of renal transplant was evaluated in 43 recipients of renal allograft. 22 out of 23 patients (95.7%) dialyzed for longer than one year had an excellent renal function at one year, while only 10 out of 20 patients (50%) dialyzed for less than one year had good renal function at one year. Only one kidney (4.3%) was lost due to rejection in the first group, while 10 kidneys (50%) failed to function because of severe rejection in the second group. The length of hemodialysis appears to have a beneficial effect on graft survival, but the mechanism by which it exerts this effect is not clear.

Correlation in hemodialysis patients and renal allograft recipients between percent T lymphocytes in peripheral blood and in vitro lymphocyte responses to nonspecific mitogenic agents

Both hemodialysis and renal allograft recipients have a significantly reduced number of total T lymphocytes per microliter of blood. Simultaneous in vitro lymphocyte responsiveness to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) revealed in the normal subjects, a positive correlation (r = +0.427) between percent T lymphocytes and PHA and a negative correlation (r = -0.525) between percent T lymphocytes and PWM. Such trends were not observed in the hemodialysis patients and transplant recipients. Thus, the enumeration of lymphocytes as T cells appears to provide no clear indication of their functional capacity to respond to mitogenic stimulation in these two categories of patients.

In vitro cellular immunity and in vivo delayed hypersensitivity in uremic patients maintained on hemodialysis

Uremic patients on hemodialysis for periods in excess of 1 year have a significantly better survival rate for their renal allografts than do similar patients hemodialyzed for less than 1 year. Lymphocytes from the patients of both groups show no difference in response in the mixed leukocyte culture reaction and to nonspecific mitogens such as PHA and PWM. A significant difference between the two groups of patients was observed with regard to their cutaneous delayed hypersensitivity reactions and in their <i>in vitro </i>lymphocyte responses to streptokinase-streptodornase. Patients hemodialyzed over 1 year were anergic to skin test antigens and had a significantly diminished <i>in vitro </i>response to streptokinase-streptodornase. Monitoring of patients for delayed cutaneous hypersensitivity reactions and for <i>in vitro </i>lymphocyte responses to streptokinase-streptodornase may be of some practical value in selecting recipients for renal transplantation.