The protective reaction of the myocardium to ischemic damage

The morphological and functional consequences of epinephrine-induced myocardial infarction were studied in normo- (Wistar) and hypertensive (ISIAH) rats. After experimental myocardial infarction there was an irreversible transition to the "worn-out" stage or "plastic damage" to the myocardium. Thus, myocardial hibernation in ISIAH rats anticipates and determines the development of myocardial stunning, i.e., irreversible myocardial damage, whereas in the normotensive animals, the protective effect of hibernation is fully shown. The ontogenetic features of myocardial response of ISIAH rats to hypoxia promote transformation of adaptive hibernation and stunning to maladaptive pathological changes causing hypoxic alterations.     

Deceiving others/deceiving oneself: four cases of factitious rape

Although patients with factitious disorders typically seek the "patient" role through illness portrayals, some instead portray themselves falsely as "victims." We discuss the cases of four women who claimed to have been victims of rape; the allegations ultimately were disproved. Factitious rape may be prompted by a search for nurturance; by dissociation, leading individuals to believe that trauma earlier in life is ongoing; by a need to be rescued from real, current abuse; and by projection of anger onto specific male targets. Although dramatic, factitious rape is rare, we advocate thorough investigation of rape claims even when patients have known histories of deceptive behavior.     

Mathematical models of marrow cell kinetics: differential effects of protracted irradiations on stromal and stem cells in mice

It is known that hematopoiesis is supported by bone-marrow stem cells, but those cells must seed and grow on a stromal microenvironment. Typically, studies have shown that a surviving fraction of about 30 hematopoietic stem cells (HSCs) (i.e., about 0.04%) correspond to the LD50, although other studies have shown that marrow can repopulate from a single viable cell under strong regiments of antibiotics and infusions of irradiated blood elements. PURPOSE: This paper describes comparisons between our results (from maximum-likelihood estimation techniques for cellular damage, repair, and compensatory repopulation) and published experimental data on marrow stromal cells. METHODS AND MATERIALS: After biophysical consideration of the rate constants that were derived by maximizing the likelihood function (a consideration necessary to extend the model to cell populations not indicated by the model as "critical" for recovery), the rate constants for cellular damage to stem cells are fitted to experimental data. Rate constants for repair and proliferation of stem cells are assigned based on published data on repair/proliferation half-times, and these assignments affect the evaluation of the rate constants for cellular damage. From the two models, that is one for "critical" cells (having radiosensitive and repopulation characteristics similar to stromal cells) and another for stem cells, effects on two cell populations of different radiosensitivities and repopulation rates can be demonstrated for complex schedules of protracted irradiations which could reduce either cell population below a critical need for marrow repopulation. RESULTS: Our analysis of animal mortality data has indicated that recovery of an animal from potentially lethal irradiation is dominantly regulated by cells with survival and repopulation characteristics similar to those of stroma cells. CONCLUSION: In contrast to the surviving fraction of hematopoietic stem cells, it appears that the probability of an animal's recovery is high if the "critical" population of cells is above 1% (our "best" maximum likelihood estimate, from mouse data, with the corresponding lower confidence bound at about 0.2%). Of course, a few stem cells--perhaps only one--must maintain a potential for repopulation of blood and marrow.     

Calculation of the extreme ultraviolet radiation of the earth's plasmasphere

The dynamic global core plasma model(DGCPM) is used in this paper to calculate the He+ density distribution of the Earth's plasmasphere and to investigate the configurations and 30.4 nm radiation properties of the plasmasphere.Validation comparisons between the simulation results and IMAGE mission observations show:That the equatorial structure of the plasmapause is mainly located near 5.5 RE and the typical scale of plasmasphere shrinking or expansion within 10 min is approximately 0.1 RE;that the plasmasp...     

Ontogeny of gonadotropin, testosterone, and inhibin secretion in normal boys through puberty based on overnight serial sampling

To investigate hormonal changes occurring in male puberty, we measured LH, FSH, testosterone, and alpha-inhibin immunoactivity in serum samples drawn every 10 min for 8 h (2100-0500 h) from each of 50 normal prepubertal and pubertal boys, aged 8.4-18.8 yr. We measured gonadotropins with ultrasensitive immunofluorometric assays, and testosterone and alpha-inhibin with RIAs. Unlike previous studies, which indexed pubertal development with Tanner stages, we used testicular volume, a more finely graduated indicator of development, to reveal patterns that were obscured when subjects were grouped by Tanner stage. The overnight mean concentration of each hormone increased with testis volume, but the rate of increase on a logarithmic scale slowed as testes grew. Log LH rose precipitously in the late prepubertal and early pubertal periods and plateaued during mid- and late puberty. Based on fitted regression curves, LH increased about 20-fold (from 0.11 IU/L) between testis volumes of 1 and 10 mL, but only an additional 1.5-fold by 30 mL. The developmental trajectory of log testosterone was like that of log LH, but rose less steeply early in puberty. From 0.14 micrograms/L at a testis volume of 1 mL, testosterone increased about 8.5-fold by 10 mL and an additional 3-fold by 30 mL. In contrast, logarithms of overnight mean FSH and alpha-inhibin concentrations rose at a more nearly constant rate throughout puberty. From 0.62 IU/L at a testis volume of 1 mL, the FSH concentration doubled by 10 mL and increased an additional 1.7-fold by 30 mL. From 270 ng/L at a testis volume of 1 mL, inhibin increased 1.5-fold by 10 mL and an additional 1.3-fold by 30 mL. Overnight pulse amplitudes exhibited developmental trajectories similar to those of the corresponding overnight mean concentrations. The number of LH and testosterone pulses during the sampling period averaged 2.2 and 2.1, respectively, at Tanner stage 1 and increased to 4.5 and 3.2, respectively, at Tanner stage 5. The number of FSH and inhibin pulses remained constant throughout puberty, averaging 3.3 and 3.5, respectively. Pairwise correlations among hormone concentrations were strong, reflecting common increasing trends through puberty; however, after accounting for developmental trends, FSH, LH, and testosterone concentrations remained correlated, whereas inhibin was uncorrelated with each of the other three hormones. Measuring gonadotropins with ultrasensitive assays and analyzing the results on a logarithmic scale as a function of testis volume made clear the dramatic hormonal changes that begin before the clinical changes of puberty.     

Molecular cloning of German cockroach (Blattella germanica) allergens

Allergens produced by cockroaches (CRs) are an important cause of IgE antibody responses and asthma. Using molecular cloning and nucleic acid hybridization techniques, we have identified and sequenced several important allergens produced by the German CR (Blattella germanica) and studied their expression in the American CR (Periplaneta americana). Principal allergens include Bla g 2 (36-kD protein) and Bla g 4 (21-kD protein), to which 60-70% of CR-allergic patients make IgE antibodies. Bla g 2 is only expressed by B. germanica, whereas DNA encoding Bla g 4 is present in P. americana, but is not transcribed into mRNA. Sequence homology searches have identified Bla g 2 as an aspartic protease and Bla g 4 as a calycin. Other CR allergens that have been cloned include a glutathione transferase and a troponin. These studies will enable recombinant allergens to be expressed and used to investigate the role of CR allergens in asthma.