Regional function-structure relationships in lungs of an elastase murine model of emphysema

Changes in lung function and structure were studied using hyperpolarized (3)He MRI in an elastase-induced murine model of emphysema. The combined analysis of the apparent diffusion coefficient (ADC) and fractional ventilation (R) were used to distinguish emphysematous changes and also to develop a model for classifying sections of the lung into diseased and normal. Twelve healthy male BALB/c mice (26 ± 2 g) were randomized into healthy and elastase-induced mice and studied ～8-11 wk after model induction. ADC and R were measured at a submillimeter planar resolution. Chord length (L(x)) data were analyzed from histology samples from the corresponding imaged slices. Logistic regression was applied to estimate the probability that an imaged pixel came from a diseased animal, and bootstrap methods (1,000 samples) were used to compare the regression results for the morphological and imaging results. Multivariate ANOVA (MANOVA) was used to analyze transformed ADC (ADC(BC)), and R (R(BC)) data and also to control for the experiment-wide error rate. MANOVA and ANOVA showed that elastase induced a statistically measureable change in the average transformed L(x) and ADC(BC) but not in the average R(BC). Marginal mean analysis demonstrated that ADC(BC) was on average 0.19 [95% confidence interval (CI): 0.16, 0.22] higher in the emphysema group, whereas R(BC) was on average 0.05 (95% CI: 0.04, 0.06) lower. Logistic regression supported the hypothesis that ADC(BC) and R(BC), together, were better at differentiating normal from diseased tissue than either measurement alone. The odds ratios for ADC(BC) and R(BC) were 7.73 (95% CI: 5.23, 11.42) and 9.14 × 10(-5) (95% CI: 3.33 × 10(-5), 25.06 × 10(-5)), respectively. Using a 50% probability cutoff, this model classified 70.6% of pixels correctly. The sensitivity and specificity of this model at the 50% cutoff were 74.9% and 65.2%, respectively. The area under the receiver operating characteristic curve was 0.76 (95% CI: 0.74, 0.78). The regression model presented can be used to map MRI data to disease probability maps. These probability maps present a future possibility of using both measurements in a more clinically feasible method of diagnosing this disease.     

Genome interdependence in insect-bacterium symbioses

Symbioses between unicellular and multicellular organisms have contributed significantly to the evolution of life on Earth. As exemplified by several studies of bacterium-insect symbioses, modern genomic techniques are providing exciting new information about the molecular basis and the biological roles of these complex relationships, revealing for instance that symbionts have lost many genes for functions that are provided by the host, but that they can provide amino acids that the host cannot synthesize.     

Lung volume and interdependence in the pig.

The effect of lung volume on the mechanical interdependence between an obstructed sublobar region of lung and its surrounding tissues was investigated in intact and isolated pig lungs. Interdependence is arbitrarily defined as the effectiveness with which the linkage between the region and surrounding tissue mediates a tendency for inflation to become even whenever it is uneven. We found that when the volume of the surrounding lung (Vl) was high relative to the volume of the obstructed region (Vr), or when they were relatively equal at higher inflation states, interdependence decreased. When Vr was high relative changes in regional shape observed during even and uneven inflation states, we suggest that regional distortion and its effects on regional elastic recoil are important determinants of pulmonary interdependence.     

Nutritional interdependence betweenThermoanaerobacter thermohydrosulfuricus andClostridium thermocellum

Thermoanaerobacter thermohydrosulfuricus strain YM3 and Clostridium thermocellum strain YM4, obtained originally as a stable coculture, required yeast extract to grow separately. Cell-free broths of T. thermohydrosulfuricus strain YM3 and C. thermocellum strain YM4 monocultures replaced yeast extract in supporting the growth of strains YM4 and YM3, respectively. T. thermohydrosulfuricus strain YM3 produced vitamin B₆, B₁₂ analog(s), p-aminobenzoic acid and folic acid, which were required by C. thermocellum strain YM4. Likewise, strain YM4 produced niacin-active compound(s), thiamine, and methionine required by strain YM3. Received: 17 March 1995 / Accepted: 27 March 1995     

Estrogens in calf embryos

A particular technique has been restated for the analysis of extradiol and extrones. Availing ourselves of such a technique, we have determined the presence of the steroid hormones, extradiol and extrones, in the calf embryos. The above studies are framed within the sphere of the researches made in our Institute, having the scope of determining the biological effects and the chemical composition of the calf embryos, which is utilized like a commercial product in some other Nations.     

Functional interdependence between septin and actin cytoskeleton

Background  

Septin2 is a member of a highly conserved GTPase family found in fungi and animals. Septins have been implicated in a diversity of cellular processes including cytokinesis, formation of diffusion barriers and vesicle trafficking. Septin2 partially co-localises with actin bundles in mammalian interphase cells and Septin2-filamentmorphology depends upon an intact actin cytoskeleton. How this interaction is regulated is not known. Moreover, evidence that Septin2 is remodelled or redistributed in response to other changes in actin organisation is lacking.