Aldosterone studies in obese patients with hypertension

Ten patients with hypertension and obesity were studied during a program of weight loss on an unrestricted sodium diet. The study showed that weight loss during the ten month period was accompanied by a significant decrease in urinary aldosterone, tetrahydroaldosterone -3-glucuronide and plasma renin activity values. It was also demonstrated that successful reduction in body weight was associated with a reduction in blood pressure. It is postulated that blood pressure reduction in obese patients during weight reduction may depend on decreases in aldosterone and plasma renin activity. The reduction in levels of tetrahydroaldosterone-3-glucuronide is due to an energy related depression of the glucuronidation process caused by carbohydrate deficiency. It is postulated that the lowered rate of metabolism of aldosterone as measured by the diminished formation of the metabolite tetrahydroaldosterone-3-glucuronide is an important determinant of blood pressure status during weight reduction.

The distribution of serum albumin in the rat testis, studied by electron microscope immunocytochemistry on ultrathin frozen sections

The distribution of serum albumin is of interest in the rat testis because this protein is the principal carrier for testosterone in the plasma and interstitial fluid of this species. We have localized extravascular serum albumin in the rat testis at the electron microscope level, using gold particle immunocytochemistry on ultrathin frozen sections of tissue fixed lightly by perfusion. The same localization was obtained with three different antisera. Preabsorption and normal rabbit serum controls were negative, and Western blots of testis extracts showed major activity only at the molecular weight of albumin. Serum albumin occurred in substantial concentration throughout extracellular space in the interstitial tissue, as well as in the space between the boundary layer and the base of the seminiferous epithelium. Immunoreactivity extended between Sertoli cells, as well as around spermatogonia and early primary spermatocytes (to stage 11), but did not traverse the Sertoli-Sertoli junctions that comprise the blood-testis barrier. Macrophages in the interstitial tissue showed some endocytic activity. If perfusion fixation was carried out in a manner that flushed most of the albumin from the interstitial space, then a layer of albumin remained on the surface of Leydig cells and many macrophages but was minimal or absent on the surface of other cell types that are normally in contact with albumin, such as Sertoli cells, spermatogonia, myoid cells, lymphatic endothelium, fibroblasts, or cells of blood vessels.

A case of visual agnosia showing a disorder of pre-semantic visual classification

A case (J.R.) of associative visual agnosia (loss of meaning for visually presented objects without any serious sensory disorder) is reported. When asked to match a given name to sample the patient made both visual and semantic errors. Whereas semantic errors were reduced by priming, visual errors were intractable. It is argued that there is a disorder at the stage of pre-semantic abstraction, similar to that postulated elsewhere for some cases of deep dyslexia, contributing to the agnosia.

Adapting "Portage" for neurological patients

Portage is a home-based teaching technique for mentally handicapped children. It would also appear to be useful for some neurologically impaired people. This paper describes how Portage has been adapted for brain-damaged adults. Three examples are given of Portage type programmes. The first describes the use of checklists for assessment of a blind aphasic woman who had suffered anoxia. The second describes part of the treatment of a woman who developed encephalitis which left her with quadriplegia. The final example outlines the treatment of a patient who had a subarachnoid haemorrhage which resulted in a fear of walking alone.

Polymeric complexes and fragments of albumin in normal human plasma

Nitrocellulose blots of normal human plasma proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were examined for polymeric complexes and fragments of albumin using an immunoperoxidase-labelled mouse monoclonal anti-human albumin antibody. Under reducing conditions, no polymeric complexes were seen. Under non-reducing conditions, polymeric complexes were detected at the following molecular weights: 210 000, 168 000, 147 000, 132 000, and 110 000. These probably represent both homo- and heteropolymers of albumin. Fresh plasma samples were also analyzed by S-200 chromatography with the same results indicating that detection of polymeric complexes was not an artifact of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique. In quantitative terms, polymeric complexes constituted 0.3-2.8% of the total albumin present. Fragments of albumin were also seen in normal human plasma with molecular weights of 45 000, 28 000 and 19 000. These fragments probably represent breakdown products of albumin in normal blood, and they constituted less than 2% of the total albumin present.

Aldosterone in acromegaly

Ten patients with acromegaly, six with active acromegaly and four with inactive acromegaly were studied with regard to the possible relationship between aldosterone metabolism and hypertension. It was noted that tetrahydroaldosterone-3-glucuronide levels were highest in those cases which exhibited the highest prolactin levels. It was in these cases that hypertension was present and they were active as judged by clinical and biochemical parameters. On administration of bromocryptine there was a reduction of tetrahydroaldosterone-3-glucuronide, prolactin and also a significant reduction of blood pressure. The significance of these results is discussed.

A comparison of deaf, normal, and brain damaged adults on a tachistoscopic task

Printed words and letters, pictures of signed words, and pictures of finger-spelled letters were presented tachistoscopically to deaf, normal, and brain-damaged adults. The findings suggest that (1) the deaf show no cerebral asymmetry for any of the material but found identification of the stimuli very difficult unless a forced-choice recognition procedure was used or the exposure time was very long; (2) both the normal and the brain-damaged groups show left hemisphere superiority for printed material but no cerebral specialization for signed material; (3) the left-right hemisphere difference is more marked in the brain-damaged group regardless of which hemisphere showed most damage. This may be explained, at least in some cases, by impaired transfer across the corpus callosum.

Effects of glyoxylate on photosynthesis by intact chloroplasts

Because glyoxylate inhibits CO(2) fixation by intact chloroplasts and purified ribulose bisphosphate carboxylase/oxygenase, glyoxylate might be expected to exert some regulatory effect on photosynthesis. However, ribulose bisphosphate carboxylase activity and activation in intact chloroplasts from Spinacia oleracea L. leaves were not substantially inhibited by 10 millimolar glyoxylate. In the light, the ribulose bisphosphate pool decreased to half when 10 millimolar glyoxylate was present, whereas this pool doubled in the control. When 10 millimolar glyoxylate or formate was present during photosynthesis, the fructose bisphosphate pool in the chloroplasts doubled. Thus, glyoxylate appeared to inhibit the regeneration of ribulose bisphosphate, but not its utilization.The fixation of CO(2) by intact chloroplasts was inhibited by salts of several weak acids, and the inhibition was more severe at pH 6.0 than at pH 8.0. At pH 6.0, glyoxylate inhibited CO(2) fixation by 50% at 50 micromolar, and glycolate caused 50% inhibition at 150 micromolar. This inhibition of CO(2) fixation seems to be a general effect of salts of weak acids.Radioactive glyoxylate was reduced to glycolate by chloroplasts more rapidly in the light than in the dark. Glyoxylate reductase (NADP(+)) from intact chloroplast preparations had an apparent K(m) (glyoxylate) of 140 micromolar and a V(max) of 3 micromoles per minute per milligram chlorophyll.

Success and failure in memory training following a cerebral vascular accident

This paper describes the treatment offered to a 51 year old man suffering from a severe memory deficit which followed a bilateral stroke. The aims of treatment were: (a) to improve memory generally and (b) to find ways to help him retain new information in 4 specific problem areas namely remembering: (i) his daily timetable, (ii) people's names, (iii) a shopping list, and (iv) short routes. A multiple baseline procedure was used to investigate this. At the end of the treatment period only slight improvement was found in his memory generally, although on a motor memory task he improved steadily throughout. Strategies were found to help him with 3 of the 4 specific problems. The fourth--remembering short routes--was resistant to all the strategies tried. The paper discusses the effectiveness of treatment, the nature of the lesion and how this case contributes towards our understanding of human memory and forgetting.

Proton motive force and the physiological basis of delta pH maintenance in thiobacillus acidophilus

At optimal growth pH (3.0) Thiobacillus acidophilus maintained an internal pH of 5.6 (delta pH of 2.6 units) and a membrane potential (delta psi) of some +73 mV, corresponding to a proton motive force (delta p) of -83 mV. The internal pH remained poised at this value through external pH values of 1 to 5, so that the delta pH increased with decreasing external pH. The positive delta psi increased linearly with delta pH: above a delta pH of 0.6 units, some 60% of the increase in delta pH was compensated for by an opposing increase in delta psi. The highest magnitude of delta pH occurred at an external pH of 1.0, where the cells could not respire. Inhibiting respiration by CN- or azide in cells at optimal pH decreased delta pH by only 0.4 to 0.5 units and caused a corresponding opposite increase in delta psi. Thus, a sizable delta pH could be maintained in the complete absence of respiration. Treatment of cells with thiocyanate to abolish the delta psi resulted in a time-dependent collapse of delta pH, which was augmented by protonophores. We postulate that T. acidophilus possesses unusual resistance to ionic movements. In the presence of a large delta pH (greater than 0.6 pH units), limited diffusion of H+ into the cell is permitted, which generates a positive delta psi because of resistance to compensatory ionic movements. This delta psi, by undergoing fluctuations, regulates the further entry of H+ into the cell in accordance with the metabolic state of the organism. The effect of protonophores was anomalous: the delta p was only partially collapsed, and respiration was strongly inhibited. Possible reasons for this are discussed.

The selection of special educators and learning disability specialists

The process that should determine the selection procedures for learning disability specialists is conceptualized. The base represents the essential qualities necessary for all special educators before they are admitted for training in the field. The second level represents qualities that can be taught and enhanced, and the third are the style of behavior and the temperament that can and should be matched with the child to form “a treatment alliance.”

The control of peroxidase-catalysed iodination and de-iodination

It has been demonstrated that the H2O2/l ratio is a critical factor in the control of iodination and de-iodination of covalently bound tyrosyl residues in proteins and free iodotyrosines by peroxidase enzymes. This has been shown for myeloperoxidase (MPO) isolated from normal human polymorphonuclear lymphocytes in particular, and also for peroxidase of animal origin such as thyroid peroxidase (TPO) and lactoperoxidase (LPO). It has been shown that the H2O2/l ratio exerts a controlling influence on MPO-catalysed reactions of fully iodinated tyrosines, e.g. di-iodotyrosine, and of partially and completely iodinated thyronines such as thyroxine and tri-iodothyronine. Using an in vivo model system it has been shown that MPO catalyses the sequential events of iodination, iodine exchange and de-iodination of tyrosines and, furthermore, that all three reactions are influenced by the rate of H2O2 generation and the iodide concentration of the reaction medium. The action of MPO on iodothyronine substrates only affects de-iodination irrespective of whether the iodothyronine is partially iodinated, as in tri-iodothyronine, or completely iodinated, as in thyroxine. This MPO-catalysed de-iodination of thyroxine and tri-iodothyronine can also be regulated by the H2O2/l ratio. Moreover, the results show that MPO-catalysed iodine exchange can only occur in completely iodinated tyrosines such as di-iodotyrosine (DIT). Iodine exchange in partially iodinated tyrosines such as mono-iodotyrosine (MIT) or in iodothyronines (T3 and T4) cannot be catalysed by MPO irrespective of the H2O2/l ratio. These results introduce a new concept which may be important in understanding the control of thyroid activity in thyroid disease and the control of MPO activity in biological defence mechanisms in man.

Studies on the retina and the pigment epithelium in hereditary canine ceroid lipofuscinosis. III. Morphologic abnormalities in retinal neurons and retinal pigmented epithelial cells

Studies of the retina in 6- and 22-month-old English setters with progressive blindness, ataxia, and muscle weakness demonstrated a marked accumulation of abnormal cytosomes within neurons and retinal pigmented epithelial cells. Ganglion cells contained abundant cytosomes with evenly spaced stacks of membranes; bipolar and amacrine cell cytosomes consisted of dense, amorphous material with closely spaced configurations of light and dark lines; cytosomes within photoreceptor cells contained faintly staining curved profiles. All three cytosomes resembled those previously reported in brain neurons of CCL dogs. In retinal pigmented epithelial cells, there were prominent accumulations of lamellar fragments, either free in the cytoplasm or incorporated into melanin granules. These retinal abnormalities are likely to be related to deficiences of peroxidase and defects of lipid peroxidation. The pathologic and biochemical changes seen in these dogs are similar in many respects to those reported in human patients with Batten disease. As such, these dogs provide a convenient model for the study disease mechanisms and for therapeutic approaches to blindness in Batten disease.