Development of Coombs positive haemolytic anaemia in NZB mice injected with Freund's complete adjuvant

Intraperitoneal injection of young adult NZB mice with Freund's complete adjuvant emulsion, alone or incorporating BALB/c mouse erythrocytes, resulted in accelerated direct Coombs conversion and development of splenomegaly. Incorporation of adjuvant with NZB erythrocytes caused an accelerated reactivity in some animals, but in others resulted in a delayed Coombs conversion. In contrast, positive Coombs tests failed to develop at all in NZB mice injected with a Freund's complete adjuvant preparation containing ten times the usual amount of Mycobacterium. These observations might be explained in part by the relative influences of adjuvancy and of antigenic competition on the availability of precursor cells capable of responding to autoantigenic stimulation.     

Life and death decisions: secondary complexes and lipid rafts in TNF receptor family signal transduction

Signaling by receptors in the TNF receptor (TNFR) superfamily mediate biological outcomes ranging from inflammation to apoptosis and other forms of programmed cell death. How receptor signaling mediates these divergent responses is just beginning to be understood. Here, we discuss how receptor submembrane localization and the formation of alternate signaling complexes can alter the fate of cells stimulated through TNFRs with a death domain, also known as "death receptors."     

Genetic analyses of gustation in the fowl

Preferences towards quinine sulfate (QS) and dextrose (DEX) were tested in purelines and reciprocal crosses of two lines of chickens that had undergone 22 generations of selection for high and low juvenile body weight. Parental line-F₁ comparisons provided evidence for non-additive genetic variation for hedonic sensitivity towards QS and DEX, though in opposite directions. Additive genetic variation appeared to influence the preference ratios for both stimuli at super-threshold concentrations. These results are discussed with regard to their evolutionary implications.     

Cephalic-phase insulin secretion in normal and pancreatic islet-transplanted rats

The ability of saccharin, in comparison with glucose and tap water, to elicit glycemia-independent neurally mediated insulin secretion was investigated in chronically catheterized, freely moving rats. Plasma glucose and insulin concentrations were measured continuously from venous blood with a sampling resolution of one per minute. In normal rats, 1 ml of 0.15% saccharin caused a significant rapid rise in peripheral plasma insulin levels lasting up to 5 min, without significant changes in glycemia. Tap water alone also induced a transient elevation in insulinemia but was much smaller than the saccharin-induced response. In streptozotocin diabetic rats bearing intrahepatic, presumably denervated islet isografts, these rapid insulin responses to oral saccharin and tap water stimulation were completely abolished, whereas the early insulin response to intravenous glucose was decreased by only about 30%. These results are consistent with the concept of gustatory and other oral sensory signals acting as triggers for neurally mediated insulin release.     

Immunohistochemical localization of apolipoproteins A-I and B in human carotid arteries

Decreased plasma levels of apolipoprotein A-I (apo A-I) and increased plasma levels of apolipoprotein B (apo B) have been shown to correlate with increased risk of atherosclerosis. While many studies have investigated the plasma levels of these apolipoproteins with regard to their value as predictors of cardiovascular disease, comparatively little is known about their precise tissue localization in atherosclerotic plaques. The purpose of this study was to determine the tissue localization of apo A-I and apo B in atherosclerotic segments of human carotid arteries through the use of immunohistochemical techniques. With tissue samples obtained from surgery and autopsy, apo A-I and apo B were found to be present in atherosclerotic plaques and absent in normal arterial tissue. In the plaques, both apo A-I and apo B were found extracellularly, primarily in the lipid core, but also in connective tissue. In addition, both apo A-I and apo B were found intracellularly in foam cells. This similar intracellular and extracellular distribution of apo A-I and apo B was unexpected, in view of their differing associations with atherosclerosis.     

Significance of hypoalbuminemia in pediatric oncology patients--malnutrition or infection?

Nutritional status was evaluated on 210 occasions in 90 pediatric oncology inpatients during a 7-month period; 39 had solid tumors and 51 leukemia. Ages ranged from 3 months to 20 yr. Nutritional parameters were defined as normal, "at risk," or "probably malnourished." Fifty-seven and 29% of assessments revealed at least one parameter "at risk" or "probably malnourished," respectively. Prognosis was negatively related to the number of abnormal nutritional parameters. Serum albumin was most frequently abnormal. However, on most occasions, hypoalbuminemia was associated with weight/height, arm muscle area, and triceps skinfold measurements in the normal range. In order to further identify determinants of serum albumin, we analyzed dietary, chemotherapy, and temperature data in 10 prospectively studied leukemia patients, half of whom received parenteral nutrition. In these patients there was little relationship of serum albumin to chemotherapy or dietary intake. In all of these patients, especially those receiving total parenteral nutrition, low serum albumin was highly associated with fever (p less than 0.0005). We concluded that febrile illness is an important determinant of abnormal serum albumin concentrations. In pediatric cancer patients, abnormal serum albumin may more often reflect the acute metabolic response to fever and infection than depletion of body mass.     

The effect of culture on how women experience menstruation: Jewish women and Mikvah

Mikvah is a practice in Judaism consisting of ritual bathing that occurs at the end of the menstrual period. This study compared 161 married Jewish women, 82 mikvah users, and 79 non-users in order to learn how this ritual affects attitudes towards menstruation and the perception of menstrual and premenstrual distress. Women participating in mikvah, a ritual that defines them as "unclean," were expected to have more negative conceptions of menstrual cycle symptomatology and more positive menstrual attitudes than women in the same culture not participating in this ritual. These hypotheses were not supported by the findings. What was found was a similarity between the two groups in attitudes towards menstruation, frequency and type of symptoms surrounding the menstrual period, and the degree to which any of these symptoms were experienced.     

Attenuation of ethanol tolerance by a novel stimulus

A Pavlovian conditioning model of tolerance emphasizes that an association between predrug cues and the systemic effects of the drug contributes to tolerance. On the basis of this model, established tolerance should be attenuated by external inhibition, i.e., by presentation of a novel, extraneous stimulus. This prediction was evaluated in the present experiment. Rats that were so tolerant to the hypothermic effect of ethanol that they evidenced no drug-induced decrease in temperature were presented with a bright strobe light following ethanol administration. The light precipitated a large decrease in temperature in these rats. These results provide further evidence that tolerance to the hypothermic effect of ethanol is, in part, mediated by learning.     

Pharmacokinetic transfer functions and generalized clearances

A generalized steady-state clearance coefficient is defined to relate drug or metabolite mass transfer rates into one area of the body (area II) to the constant drug concentration in another area (area I). It is demonstrated that this clearance coefficient may be used in the transient case to calculate total mass transfer into area II when the drug AUC in area I is known. This generalizes the well-known "clearance formula" CL = Ae/AUC to cases in which several compartments separate areas I and II, as well as to cases where distributed models are preferred. Several applications are discussed, including a noninvasive means of determining the fraction absorbed of topically administered drugs.     

Hostage hallucinations. Visual imagery induced by isolation and life-threatening stress

The literature on hallucinatory experiences of hostage victims is reviewed. The phenomenology is examined in 30 case studies involving 31 persons, including ex-prisoners of war and victims of rape, kidnapping, terrorism, robbery, and "UFO abductions." The victims were subjected to conditions of isolation, visual deprivation, restraint on physical movement, physical abuse, and the threat of death. For eight victims, these conditions were sufficient to produce a progression of visual hallucinations from simple geometric images to complex memory images coupled with dissociation. The other 23 victims, subjected to similar conditions but without isolation and life-threatening stress, resulting from the threat of death, did not experience hallucinations. The hostage hallucinations are compared to those resulting from sensory deprivation, near fatal accidents, and other states of isolation and stress. A common mechanism of action based on entoptic phenomena and CNS excitation and arousal is suggested.