Circadian and circannual variations in plasma immunoreactive insulin (IRI) and C-peptide concentrations in elderly subjects

Groups of 49-51 elderly men and women 77 +/- 8 years of age, institutionalized at the Berceni Clinical Hospital, Bucharest, Romania, were studied over a 24 hour span in spring, summer, fall and winter. All subjects followed a diurnal activity pattern with rest at night and ate three meals per day with breakfast at about 08:30, lunch at about 13:00, dinner at 18:30. The meals were similar, although not identical for all subjects during all seasons. On each day of sampling, blood was collected at four hourly intervals over a 24 hrs span. Immunoreactive insulin (IRI) and C-peptide were determined in plasma and glucose (during fall and winter only) in serum. Circadian variations of all three parameters were found and the rhythm parameters were determined statistically by cosinor analysis. The acrophases of the circadian rhythm of IRI and C-peptide were the same during all four seasons. The circadian acrophase of plasma IRI and C-peptide precedes that of serum glucose. The circadian mean concentrations of IRI and C-peptide show a circannual variation with higher values in winter and fall than in spring and summer for plasma insulin and with higher values for summer and fall than in spring for C-peptide. Sex differences in IRI and C-peptide concentrations with higher values in men are manifested during certain circadian and circannual stages but not during others.

The relationship zinc--alkaline phosphatase activity in normal and pathologic granulocytes

To study the relationship granulocyte alkaline phosphatase (AP)--zinc (Zn) in mixed leukocyte suspensions, the enzyme from 51 mixed leukocyte suspensions was separated and purified. In the pure extract, determinations were carried out for enzymatic activity--using the autoanalyzer LKB 8600--and for Zn content--using atomic absorption spectrophotometry. From the data obtained it resulted that, in agreement with the results in the literature Zn concentration in the mixed leukocyte suspensions from chronic myeloid leukemia, (CML) patients is about half that in the normal controls (0.65 +/- 0.15 as compared with 1.24 +/- 0.15 micrograms/mg total nitrogen). Granulocyte AP separated from normal leukocyte suspensions was found to bind about 95% of the total Zn content, i.e., 1.21 +/- 0.15 micrograms/mg total nitrogen and its enzymatic activity was about 16 U/g total nitrogen. In CML patients the enzyme bound a mean Zn concentration of 0.55 +/- 0.15 micrograms/mg total nitrogen and its mean activity was 2.25 U/g total nitrogen, i.e., about 86% of the normal values found in the controls. The enzymatic activity decreased to zero after only 20 min dialysis with 8-hydroxyquinoleine-5-sulfonic acid (8HC5S) as compared with the 60-80 min in the controls. It can be concluded that the leukemic leukocyte is unable to form the metal-enzyme complex owing to the deficit of the Zn involved in the enzymatic activity.

Circadian periodicity of the results of frequently used laboratory tests in elderly subjects

The circadian rhythms of twenty-one chemical serum parameters (albumin, alkaline phosphatase, calcium, carbon dioxide content, chloride, cholesterol, creatine phosphokinase (CPK), creatinine, glucose, glutamic-oxalacetic transaminase (GOT), gamma glutamyl transferase (Gamma--GT), lactate dehydrogenase (LDH), inorganic phosphorus, iron, potassium, total bilirubin, total protein, sodium, triglycerides, urea nitrogen, uric acid) and of urinary volume and oral temperature were studied, in October 1981, in a group of 49 elderly subjects (23 men, 73 +/- 6 years of age, and 26 women, 77 +/- 8 years of age) institutionalized at the Berceni Hospital for the aged. Statistically significant circadian rhythms as a group phenomenon were found in all functions except alkaline phosphatase, GOT, and LDH. The timing and the extent of these rhythms are presented. The circadian time structure of body chemistry appears well maintained in old age. Some circadian rhythms show a large enough amplitude to require the establishment of time qualified reference ("normal") ranges (e.g. serum iron). In most others, the circadian amplitudes are small and at present of little or no diagnostic importance. They are, however, of physiologic and pathophysiologic interest indicating an intricate time sequence of metabolic events in the human body.

Multiplication of lymphocytic choriomeningitis virus in thymocytes during its persistence in mice

Persistence of lymphocytic choriomeningitis (LCM) virus in mice infected in utero or neonatally is due to impairment of the specific subsets of thymus-dependent lymphocytes which, in the adult normal mouse, are involved in elimination of LCM virus. Virus-thymocyte interactions were studied since it was likely that this impairment takes place in the thymus. Using an infectious centre assay, we found that about 1% of the thymocytes from foetal and neonatal mice were productively infected by the virus while thymocytes from older mice were refractory to infection. The infected cells were Thy 1-positive and agglutinated by peanut lectin together with immature lymphocytes. Later, when virus persistence was established, the number of infected thymocytes declined to about 0.1% and these cells were not agglutinated by lectin. The results are compatible with the assumption that thymic precursor T-cells capable of elimination LCM virus are chronically infected by the virus and rendered non-functional.

Procedure for titration of interleukin-2 based on direct observation of factor-dependent growth of cells

A semi-quantitative procedure for titration of interleukin-2 (IL-2) without the use of radioactive labeling of IL-2 target cells was developed. The procedure is based on the observation that those cells cultivated in round-bottom wells formed visible cultures and that the dimension of these cultures decreased at higher dilutions of IL-2 in the medium. The end-point of the titration can be easily established by observing the cultures with a concave mirror placed under the titration plate. The procedure has been used for the determination of IL-2 during its purification and characterization.

Endocrine circadian time structure in the aged

Thirteen circadian rhythms in plasma hormone levels (ACTH, aldosterone, cortisol, C-peptide, insulin, DHEA-S, estradiol, LH, prolactin, 17-OH progesterone, testosterone, T4 and TSH) were studied in April 1981 in 25 males and 25 females 57 to 91 years of age, institutionalized at the Berceni Hospital for the aged. The radioimmunoassays and the statistical rhythmometric evaluation by the cosinor procedure were done at S. Paul-Ramsey Medical Center, St. Paul, MN, USA. Circadian rhythms were found and quantified for each of these variables. Elderly subjects of both sexes thus maintain a circadian time structure of their endocrine system as a group phenomenon. In comparison with previous data from the Endocrine Rhythms Laboratory ("C. I. Parhon" Institute) and series of younger subjects studied in Minnesota (St. Paul-Ramsey Medical Center) as well as in comparison with data published from other centers, the aged seem to experience an earlier arousal of their endocrine system which may be related to certain disturbances of old age e.g. of sleep. The latter observations will have to be confirmed by additional studies which take both circadian and circannual variations in account.

[Tuberculosis in the industrial environment. Epidemiological aspects and preventive measures]

An analysis is made of the tuberculous endemia in several of the most important industrial branches over the last years, as compared with the endemy outside the industrial environment. Although the global morbidity through tuberculosis in industrial enterprises has declined to approximately one half of the initial values (considering the year 1975 as the basis), it is still above the level in the territory. The gap between the two curves, much wider at the beginning of the interval, has narrowed consistently with time. The factors are discussed, that may determine this relative morbidity, and the necessary measures for their neutralization. The necessity for a close cooperation is stressed, between the enterprise physician and the pneumologist (or phthisiologist) from the territorial polyclinic.

[Therapeutic management of fracture-induced osteitis]

Fractural osteitis is considered to be exclusively of external origin, being due either to accidental wounds, or to operatory wounds. The infection is usually either with a single strain of germs, or with a small number of strains, most frequently a staphylococcus strain with a necrototizing effect on the bone structure. The prophylaxis has a determinant role, and the authors stress the organisatory measures, as well as the medical attitudes that should prevail in the face of an open fracture. In the case of closed fractures that have been infected as a result of surgery the necessity for an "early reintervention" is stressed. Late postoperative osteitis may develop in a consolidated focus, and is called osteitis of the repaired bone. It may also develop as an osteoarthritis or, and this is more serious, as a suppurated pseudarthrosis. The therapeutic attitude depends on the condition, and may consist in the removal of the osteosynthesis material, removal of the sequestered bone tissue, a so-called: "mis-à-plat" of the cavity with muscular tissue and application of septopal pearls, or a two-stage spongious graft according to Papineau, under protection of the external fixation when the necessity arises.

[Correlations between conventional allergometry and the Palmer types in interpretation of tuberculin skin tests]

In view of differentiating post-vaccinal allergy from that developing after tuberculosis infection, the authors have investigated comparatively intradermal-reactions to tuberculin according to classical allergometry, and to the 4 types described by Palmer-Edwards in a group of 1549 students and 211 patients. All the subjects were tested with 2 units of PPD IC 65. It was noted that the type I and II Palmer reactions corresponded, in the majority of the cases, to intense, or hyperergic ID reactions, while the types III and IV of Palmer corresponded to slightly positive, or to negative ID reactions. The presence of the post-vaccinal scar does not appear to influence significantly the type of the reaction, but the presence of active specific lesions is accompanied by reactions of type I and II of the Palmer classification. It is concluded that although the Palmer types do not allow to make a clear differentiation between the two variants of allergy they provide however useful indications for the interpretation of IDR in a more sophisticated manner, as compared with the conventional allergometry.