Behavioral Ecology of Sympatric Chimpanzees and Gorillas in Bwindi Impenetrable National Park,Uganda: Diet

Via a field study of chimpanzees (Pan troglodytes schweinfurthii) and gorillas (Gorilla gorilla beringei) in Bwindi Impenetrable National Park, Uganda, we found that their diets are seasonally similar, but diverge during lean seasons. Bwindi chimpanzees fed heavily on fruits of Ficus sp., which were largely ignored by the gorillas. Bwindi gorilla diet was overall more folivorous than chimpanzee diet, but was markedly more frugivorous than that of gorillas in the nearby Virunga Volcanoes. During 4 mo of the year Bwindi gorilla diet included more food species than that of the chimpanzees. Three factors in particular—seasonal consumption of fibrous foods by gorillas, interspecific differences in preferred fruit species, and meat consumption by chimpanzees—contributed to dietary divergence between the two species. When feeding on fruits, gorillas ate Myrianthus holstii more frequently than chimpanzees did, while chimpanzees included more figs in their annual diet. Chimpanzee diet included meat of duikers and monkeys; gorilla frequently consumed decaying wood.     

TREATMENT OF DIABETIC PATIENTS—Observations on the Use of Carbutamide and Tolbutamide

Of a group of 32 patients with diabetes, 26 had a favorable modification of the disease in response to administration of butyl-sulfonyl-urea. All but one of the patients who had good response were past the age of 38. All diabetic patients included in this group were those with little or no tendency to ketosis after cessation of insulin administration. No toxic manifestations were noted except for a slight decrease in leukocytes in one case.     

Surgical stress impairment of murine natural killer cell cytotoxicity involves pre- and postbinding events

NK cell cytotoxicity may provide an important first line of defense against the implantation of circulating tumor emboli. Previously we reported that murine hind limb amputation induces a rapid and marked impairment of perioperative NK cell cytotoxicity that is associated with increased metastatic activity compared to unmanipulated tumor-bearing controls. Because tumor emboli are systemically discharged in patients undergoing solid tumor resection, we thought it pertinent to begin examining the mechanism underlying the perioperative impairment of murine NK cell cytotoxicity. Studies presented in this report suggest that the mechanism of impairment is multifactorial and includes the surgical stress-induced expansion of splenic erythroblasts that successfully compete with NK cells for YAC-1 target binding sites. In addition, although there is no surgically mediated decrease in splenic NK cell content (as defined morphologically, phenotypically, and functionally), there is an acute decrease in maximal NK cell recycling capacity. An accurate understanding of the mechanisms mediating perioperative impairment of NK cell cytotoxicity may be important in the future development of NK-specific perioperative immunomodulation strategies.     

Semi-quantitative estimation of changes in noradrenaline content and intraneuronal distribution in the rat vas deferens by fluorescence histochemistry

Summary A semi-quantitative histochemical assay for noradrenaline was developed, based on the assumption that the rate of reaction of noradrenaline with paraformaldehyde depends on transmitter concentration. Changes in organ noradrenaline content caused by drugs or cold-stress were associated with similar changes in fluorescence intensity of organ samples taken for microscopy. Differences in the fluorescence intensity of experimental and control tissues were also found when there was no change in total noradrenaline content, suggesting that fluorescence intensity is not a simple function of whole organ noradrenaline content. Changes in the relative fluorescence of experimental tissues with different paraformaldehyde exposures suggested that the intraneuronal distribution of noradrenaline may affect the rate of development of fluorescence. Analysis of the time course of the fluorescence reaction showed that this was best described by the sum of two first-order exponential components of different half-life. Further results suggested that the first, fast component represents vesicle-bound noradrenaline, while the slow component represents extragranular transmitter.     

Rats' memory for event duration: differential effects of delaying the discriminative choice cue as opposed to the opportunity to execute the choice response

Rats were trained to discriminate short or long durations of houselight illumination using a choice procedure. During the test phase of each trial, the left and right levers were presented with an auditory cue above one of them on (cued lever) while the other was off (uncued lever). The auditory cue was presented immediately after sample offset and the levers were inserted after the auditory cue had been presented for 2 s. For half of the rats, the correct response following the short sample was to press the cued lever, while following the long sample, it was to press the uncued lever. This was reversed for the remaining rats. Following acquisition of the discrimination, two different types of delay tests were administered. In the first set, the delay between offset of the sample and onset of the auditory cue was manipulated (Cue Delay Test). In the second set, the delay between onset of the auditory cue and entry of the levers into the chamber was manipulated (Response Delay Test). Cue Delay testing resulted in a choose-long bias at the longer delays. Response Delay testing did not result in a systematic response bias and there was little forgetting over the delay interval. These data suggest that the rats did not stop the internal clock when the nominal sample was offset, but allowed it to keep running until the auditory cue was presented. The data from the Response Delay Test indicate that either a response decision was made based on the clock reading as soon as the auditory cue was presented, or the clock reading itself was retained over the delay with no subjective shortening and little forgetting.