Aging is a process accompanied by progressive susceptibility to disturbances and impairments in adaptability. The influence of age on the capacity to adapt to chronic normobaric hypoxia (10%) was studied in 4, 20 and 27 month old rats. Adaptation was measured for four days by food and fluid intake and spontaneous activity. In addition the values of the pO2, pCO2, pH-value, Na+ concentration and hematocrit were determined. The results show an initial marked decline for the three modalities of behavior in all age groups. While age-dependent differences were exhibited, for the adaptation course in nourishment and spontaneous activity, the values of the blood gases and hematocrit did not reveal age-related changes. Thus, physiological parameters and behavior are not consistent regarding the effects of age on adaptation capacity.

Adaptation, Physiological↗

PubMedDate not supplied

Influence of normobaric hypoxia on learning capacity of different aged rats.

In this study it was tested to what extent subchronic normobaric hypoxia (10% oxygen by volume) influences the learning performance of rats of different ages (4, 20, 30 months). The animals were presented with two successive conditioning patterns (FR 10/DRL). After acquisition of the FR 10 under normoxic conditions in a Skinner box the rats needed to reestablish the learned behavior under normoxia and further under hypoxia. Following this, the rats had to learn the DRL in a test chamber under the conditions of reduced oxygen. Their performance was compared with that of control animals which had to accomplish the tasks under normoxia. No age differences were observed under normoxia in learning the FR 10. However, the reestablishment of FR 10 under hypoxic conditions was less well performed by old rats than younger ones. The young rats (4 months) had a high efficiency level on the DRL-schedule under normoxia which was not impaired by hypoxia. The old rats (30 months) had considerably lower performance level under normoxia which was not further reduced in individuals by hypoxia. The performance of the middle group (20 months) was, under normoxia, at an intermediate level, while oxygen reduction led to a pronounced reduction in efficiency.

Adaptation, Physiological↗

PubMedDate not supplied

Tumor M2 pyruvate kinase in plasma of patients with urological tumors.

The M2 isoenzyme of pyruvate kinase (M2-PK) is specifically expressed in tumor cells (TU M2-PK) and may therefore provide a tumor marker for malignancies. We have investigated the plasma concentrations of TU M2-PK in patients with renal cell carcinoma (RCC), transitional cell carcinoma of the bladder (BCA), prostate cancer (PCA) and benign prostatic hyperplasia (BPH). TU M2-PK was quantified with a commercially available enzyme-linked immunosorbent assay (ELISA) kit. Using this ELISA kit, plasma samples of 57 healthy individuals were compared to 63 patients with RCC, 36 patients with BCA, 58 patients with PCA and 28 patients with BPH. Patients with carcinomas were subdivided into those patients with nonmetastatic and those with metastatic disease. Only patients with RCC (nonmetastatic and metastatic) showed significantly increased concentrations of TU M2-PK compared to normal individuals. In metastatic RCC, TU M2-PK levels were highest and were also significantly enhanced compared to nonmetastatic RCC. The sensitivity for nonmetastatic RCC was 27.5% and for metastatic RCC 66.7% at the 95% reference value of the control group. In BCA, PCA and BPH, no significant differences could be detected. Our results indicate that TU M2-PK concentrations in plasma may be a potential biomarker of advanced RCC.

Biomarkers, Tumor↗

PubMedDate not supplied

Renal norepinephrine content decreases after chronic flow probe implantation.

Electromagnetic flow probes were chronically implanted around the left renal artery in 6 female beagle dogs. 3-10 months after implantation, renal cortex norepinephrine contents of right and left kidneys were compared (liquid chromatography). In 4 out of the 6 dogs investigated 3-6 months after implantation, the norepinephrine content of the left kidney was reduced by 27-72%. In 2 dogs investigated 7 and 10 months after implantation, the difference between left and right kidney was not significant. These findings should be taken into consideration when interpreting results from chronically instrumented kidneys.

Animals↗

PubMedDate not supplied

The tumor marker tumor M2-PK: an application in the diagnosis of gastrointestinal cancer.

The present study is designed to evaluate the use of the tumor marker Tumor M2-PK in the discrimination between gastrointestinal (Gl) cancer patients and patients with non malignant gastrointestinal diseases. The concentration of Tumor M2-PK was analyzed in EDTA-plasma of 413 Gl cancer-patients and 141 patients with non-malignant diseases. The test resulted in a highly significant discrimination (p < 0.001) of tumor patients and controls. The diagnostic specificity was 89%. A diagnostic sensitivity between 48% and 73%, depending on the different tumor entities (colorectal cancer, gastric cancer, oesophageal cancer and pancreatic cancer), was observed. These sensitivities were generally higher when compared with those of the established tumor markers CEA, CA 19-9 and CA 72-4, with the exception of CA 19-9 in pancreatic cancer. A combination of Tumor M2-PK with the appropriate first choice-marker (e.g. CEA + Tumor M2-PK for colorectal cancer) resulted in a remarkable increase in the sensitivities.

Biomarkers, Tumor↗

PubMedDate not supplied

Age-related changes in glutamate receptors: an autoradiographic analysis.

The aim of the present study was to evaluate age-related changes in NMDA and AMPA receptors in old female rats. To this end a quantitative autoradiography of [3H]-MK-801 and [3H]-AMPA binding was performed in the brain of young (3-month-old), middle-aged (12-month-old) and old (36-month-old) rats. Moreover, the binding of [3H]-spiperone to D2 dopamine receptors was also examined. No changes were observed in the binding of [3H]-MK-801 or [3H]-AMPA in middle-aged rats compared to young ones. In the caudate-putamen and shell and core of the nucleus accumbens septi of old rats, a pronounced decrease in the [3H]-MK-801 binding and a decreasing tendency in the [3H]-AMPA binding were observed. Furthermore, the binding of [3H]-MK-801 and [3H]-AMPA was reduced in the hippocampal formation and, additionally, a marked decline in the [3H]-MK-801 binding in different parts of the cerebral cortex including the frontal, parietal, cingulate, pyriform and insular cortices was found. The [3H]-spiperone binding progressively decreased with age in the dorsolateral, ventrolateral and medial caudate-putamen. The present results show that aging processes lead to changes in the binding of both [3H]-MK-801 to NMDA and [3H]-AMPA to AMPA receptors in a number of structures, a phenomenon which may reflect motor and memory disturbances found in old rats and elderly humans.

Aging↗