Geographical distribution of elderly people in Croatia.

The authors outlined the geographical distribution of individuals displaying longevity in the Republic of Croatia. Elderly people, aged 80 years and older, have been the subject of this study and were viewed in several aspects including the number of elderly people and age-specific mortality rate by districts. Data for the years 1981 and 1991 were reviewed. In 1981 there were 73,052 (1.6%) persons aged 80 or older. Ten years later in 1991 their number had increased to 107,256, which was 2.2% of the whole population. Most of the elderly people live on the islands, in the district of Dubrovnik and in Lika, which is in the continental part of Croatia. There are more women than men among those aged 80 years and older Age-specific mortality rate in 1981 in Croatia was 170 and in 1991 151 per 1,000 elderly people. In women the rate was 162 in 1981 and 141 in 1991, per 1,000 elderly people. The death rate was higher in men; in 1981 it was 201 and in 1991, 172 per 1,000 elderly people. We can see that the specific mortality rate had fallen in 1991 compared to 1981. The age specific mortality rate varies from district to district. In 1991 the lowest, 110 per 1,000, was in Lika, and the highest in the districts of Varazdin (182 per 1,000), Bjelovar (178 per 1,000) and Zagorje (175 per 1,000). The death rate was higher amongst elderly men (172.31 per 1,000) than elderly women (141.65 per 1,000). The smallest number of those aged 80 years and older with a high death rate is found in Slavonia. The opposite--a high number of elderly people and a low specific mortality rate--can be seen in the district of Lika. On the islands the number of elderly people is high, especially women, and surprisingly, the specific mortality rate is relatively high as well.

Influence of NH(4)CI on polarized release of endogenous protein degradation products and on morphology in LLC-PK(1) cells.

Increased renal ammoniagenesis is thought to be a causative factor for renal hypertrophy which occurs in several disorders accompanied by metabolic acidosis. We studied the influence of ammonia on the polarized release of degradation products of endogenous proteins in LLC-PK(1) cells. Release of acid-soluble radioactivity to the extracellular space decreased under the influence of NH(4)Cl with a remarkable transient reduction of basolateral release. Electron microscopically NH(4)Cl-treated cells showed numerous enlarged lysosomes suggesting an accumulation of incompletely degraded cytoplasmatic material in the lysosomal compartment. We conclude that split products of lysosomal degradation of endogenous proteins are preferentially transported to the extracellular space via the basolateral plasma membrane.

Whole-Nodule Carbon Metabolites Are Not Involved in the Regulation of the Oxygen Permeability and Nitrogenase Activity in White Clover Nodules.

To test the hypothesis of an indirect or direct involvement of carbon metabolites in the short-term regulation of nitrogenase activity, nodule O2 permeability was manipulated either by defoliation or by varying rhizosphere O2 partial pressure. In contrast to defoliation, a 50% reduction of the nodule O2 permeability, due to adapting nodules to 40 kPa O2, had no effect on nodule sucrose concentration. Likewise, total concentrations of other carbon metabolites such as fructose, starch, L-malate, and succinate tended to be differentially affected by the two treatments. Upon defoliation, carbon metabolites in roots responded in a manner similar to those in nodules. Sucrose concentration in nodules decreased significantly after the removal of 40% of the leaf area, which is known to have no effect on nitrogenase activity and O2 permeability. During regrowth after a 100% defoliation, nitrogenase activity could be increased at any time by elevating rhizospheric O2 partial pressure. Thus, during the entire growing cycle nitrogenase activity seems primarily oxygen limited. Changes in whole nodule sucrose pools after defoliation have to be viewed as secondary effects not necessarily linked to nodule activity. Whole-nodule carbon metabolites appear not to be determinants of nodule activity, either through direct metabolic involvement or through indirect effects such as triggering O2 permeability.

Current Nitrogen Fixation Is Involved in the Regulation of Nitrogenase Activity in White Clover (Trifolium repens L.).

Previous studies have shown that nitrogenase activity decreases dramatically after defoliation, presumably because of an increase in the O2 diffusion resistance in the infected nodules. It is not known how this O2 diffusion resistance is regulated. The aim of this study was to test the hypothesis that current N2 fixation (ongoing flux of N2 through nitrogenase) is involved in the regulation of nitrogenase activity in white clover (Trifolium repens L. cv Ladino) nodules. We compared the nitrogenase activity of plants that were prevented from fixing N2 (by continuous exposure of their nodulated root system to an Ar:O2 [80:20] atmosphere) with that of plants allowed to fix N2 (those exposed to N2:O2, 80:20). Nitrogenase activity was determined as the amount of H2 evolved under Ar:O2. An open flow system was used. In experiment I, 6 h after complete defoliation and the continuous prevention of N2 fixation, nitrogenase activity was higher by a factor of 2 compared with that in plants allowed to fix N2 after leaf removal. This higher nitrogenase activity was associated with a lower O2 limitation (measured as the partial pressure of O2 required for highest nitrogenase activity). In experiment II, the nitrogenase activity of plants prevented from fixing N2 for 2 h before leaf removal showed no response to defoliation. The extent to which nitrogenase activity responded to defoliation was different in plants allowed to fix N2 and those that were prevented from doing so in both experiments. This leads to the conclusion that current N2 fixation is directly involved in the regulation of nitrogenase activity. It is suggested that an N feedback mechanism triggers such a response as a result of the loss of the plant's N sink strength after defoliation. This concept offers an alternative to other hypotheses (e.g. interruption of current photosynthesis, carbohydrate deprivation) that have been proposed to explain the immediate decrease in nitrogenase activity after defoliation.

[Quantitative histological observations in gliomas (author's transl)]. / Quantitative histologische Untersuchungen an Gliomen.

30 autopsy cases of gliomas (5 fusiform glioblastomas, 5 multiform glioblastomas, 5 fibrillary astrocytomas, 5 protoplasmic astrocytomas, 5 oligodendrogliomas, 5 spongioblastomas) were studied by means of morphometry. 7 parameters (volume and area parameters of tumor vessels and of tumor cell nuclei, mitoses) were tested for the ascertainament of useful quantitative criteria for the objective differentiation of the gliomas. 210 statistical comparisons were carried out. Significant differences were observed in 32 of them. It could be demonstrated that the parameters of the tumor cell nuclei are most useful in the differentiation of the gliomas. Significant differences do not exist between fusiform glioblastoma--multiform glioblastoma, fusiform glioblastoma--oligodendroglioma, fibrillary and protoplasmic astrocytoma--spongioblastoma.

Mouse immunoglobulin mu heavy chain mRNA of Y5781, a high yield myeloma.

The BALB/c myeloma tumor, Y5781, has a high level of mu heavy chain mRNA and kappa light chain mRNA, as suggested by denaturing gel analyses of poly(A)-rich, total polysomal mRNA, and confirmed for the mu heavy chain mRNA by kinetic complexity analyses. Both the mRNA coding for the heavy and light chains appear as very prominent and discrete peaks above the generally polydisperse background of the total polysomal mRNA. This mRNA level appears to be stable through a limited number of subcutaneous passages of this myeloma, providing a potentially useful system for mu heavy chain mRNA synthesis and processing. The mu heavy chain mRNA of this myeloma has been enriched to about 60% homogeneity by physicochemical means. In agreement with a previous report (Faust, C.H., Jr., Heim, I., and Moore, J. (1979) Biochemistry 18, 1106-1119), the following physical and biological properties were observed. The mature cytoplasmic mu heavy chain mRNA is 950,000 daltons, i.e. about 2800 nucleotides, and contains approximately 800 undefined, nontranslated bases. In an mRNA-dependent cell-free system, this mRNA stimulates the synthesis of a single, serologically reactive mu heavy chain-like protein, confirmed by tryptic peptide maps.