Serum lysozyme (muramidase) levels in healthy subjects aged 10-90 years

Lysozyme (LYS) levels were tested in the serum of 1,399 subjects (670 males, 729 females). A curve was plotted from the mean values. In our series, both sexes attained their highest peak at about 10 years. Between 21 and 30 years the curves of the two sexes began to diverge and in the 31- to 40-year decade the male curve attained a second maximum. This inter-sex difference was highly significant (P less than 0.01). Between 41 and 50 years the LYS values of the two sexes began to come closer again and from the 51- to 60-year decade they ran parallel with each other without deviating. The significance of the two courses is discussed.     

Serum pepsinogens and gastrins in chronic hemodialysis patients

Gastrointestinal symptoms commontly associate with uremia include nause, vomiting, diarrhea, and gastrointestinal bleeding (1). Although maintenance hemodialysis alleviates many of these symptoms, the persis tent high incidence of gastrointestinal complaints in these patients is well documented (2–4). Symptoms may vary from mild dyspepsia to severe peptic ulceration and bleeding requiring surgery. A high incidence of hermorrhage from gastrointestinal ulcers and gastritis also occurs in trans plant recipients (5). The reasons for the increased incidence of upper gastrointestinal sypmtoms and lesions in uremia are not clearly under stood. Earlier studies (6,7) of chronically uremic patients reported hypo or normo-chlorhydria, but more recent studies of maintenance dialysis patients also show hyperchlorhydria (2–4). The correlation be tween gastric acid secretion and peptic ulceration is not absolute. Pepsin, gastrin, stress, ect. are also implicated in the etiology of peptic ulcer disease. The following study presents some observations about the relationships between clinical symptoms, rerum gastrin levels, and rerum pepsinogen levels, in maintenence hemodialysis patients.     

Levels of secretory immunoglobulin A, lysozyme (muramidase) and albumin in healthy adults of different ages

The content of secretory IgA (sIgA,) lysozyme and albumin was studied in the saliva of 40 health-service employees of different ages without evident signs of disease. The levels of lysozyme decrease significantly with the advancing age whereas those of sIgA and albumin do not decrease up to the age of 55. The levels of lysozyme and sIgA show a significant mutual correlation.     

Excretion of inhibitors of calcification in urine Part II. Findings in patients with chronic renal failure.

By means of a semiquantitative method incorporating the rachitic rat cartilage technique, the total urinary inhibitory activity with respect to calcification was compared in 11 control subjects and 20 patients with renal failure. The patients had significantly lower mean values of inhibiting units per day than did the control subjects. Both groups showed a significant positive correlation between the number of inhibiting units per day and urine volume. When urine volume was taken into account in the comparison, the numbers of inhibiting units for patients continued to be lower than the numbers for controls. These findings are consistent with the hypothesis that the increase of inhibitory activity observed in uremic serum is secondary to a decrease in excretion of the responsible factor (or factors) in the urine, and that the factor (or factors) in serum responsible for the inhibition are identical to those in the urine.     

Effects of chronic hemodialysis on thyroid function in chronic renal failure

Thyroid function was studied in 54 patients undergoing chronic hemodialysis. Serum thyroxine, triiodothyronine and free thyroxine and the free thyroxine index were significantly lower than normal. The levels of both serum thyroxine and the free thyroxine index tended to fall progressively the longer the patients were on hemodialysis. These findings, in association with low serum TSH levels and normal increase in radioactive iodine uptake by the thyroid after TSH injection, suggest that a defect in pituitary secretion of TSH may be responsible. Although some patients experienced symptomatic improvement after treatment with L-thyroxine the efficacy of this form of treatment in patients on chronic hemodialysis has not yet been established.     

II. Plasma and brain catecholamines in experimental uremia: Acute and chronic studies

To evaluate the role of catecholamines (CA) in uremia, we used “high performance” liquid chromatographic technique with electrodetection to determine plasma and brain concentration of dopamine (DA), norepinephrine (NE) and epinephrine (E) in rats with acute and chronic uremia. The results revealed a steady elevation in plasma CA (p < 0.05) in both acutely and chronically uremic rats when compared to the level of these neurotransmitters in controls. The highest changes were observed in DA and the least in NE (16.8 ± 3.2 vs. 0.5 ± 0.2 ng/ml and 93.2 ± 11.1 vs. 68.1 ± 16.3 ng/ml. There was a positive correlation between plasma CA and the duration of uremia (r = 0.97; p < 0.05). The elevations were more pronounced in acutely uremic rats than in chronically uremic rats. This was followed by a concomitant depletion in the concentration of DA, NE and E in the brain. The defects in catecholaminergic neurotransmission as evidence of dysfunction in the autonomic nervous system may contribute to the development of neuropathy.     

Studies on phytoplankton pigments in porto novo waters (India). II. Backwater

The annual variations of phytoplankton pigments were studied from January to December, 1971 at four stations in the backwater area (Porto Novo, India). At these stations, chlorophyll a varied from 2.91–65.56 μg/1; chlorophyll b from 0–1.90 μg/l; chlorophyll c from 0–38.60 μg/1; plant carotenoids from 0.30–22.34 MSPU/m³ and phaeopigments from 0–31.51 μg/l. The main (or primary) maximum of chlorophyll a appeared during June at Stations 3–5 and at Station 6, it was during May. Stations 3 and 4 had secondary chlorphyll a maxima during September and at Stations 5 and 6 during August. In general, all the stations showed an increasing trend of chlorphyll a values before the main peak. The chlorophyll a maximum was mainly due to the presence of phytoplankton species belonging to the genera such as Noctiluca, Coscinodiscus, Thalassiothrix, Biddulphia, Hemidiscus, Melosira and Rhizosolenia. Amongst all the backwater stations, Station 5 had the highest chlorophyll a (65.56 μg/1) and the lowest chlorophyll a was recorded at Station 3. Chlorophyll a concentration was normally affected by rainfall.     

Studies on protein folding,unfolding, and fluctuations by computer simulation. II. A. Three-dimensional lattice model of lysozyme

A three-dimensional lattice model of protein designed to assimilate lysozyme is introduced. An attractive interaction is assumed to work between preassigned specific pairs of units, when they occupy the nearest-nighbor lattice points. The behavior of this lattice lysozyme is studied by a Monte Carlo simulation method. Because of the specific interunit interactions,“native state” of the lattice lysozyme is stable at low temperatures. Conformational fluctuations in the native state are observed to occur at both termini and loop regions of the main chain existing on the surface. The process of unfolding and denatured states of this model are discussed. Complete refolding from a denatured state was not observed. However, by starting from partially folded structures, the native conformation could be attained. From these observation it is concluded that, in the process of folding of proteins as simplified in a lattice model, nulceation is a rate-limiting factor. The artificial character of this model and possible improvement are discussed.