Scaling physiological measurements for individuals of different body size

This paper examines how selected physiological performance variables, such as maximal oxygen uptake, strength and power, might best be scaled for subject differences in body size. The apparent dilemma between using either ratio standards or a linear adjustment method to scale was investigated by considering how maximal oxygen uptake (l.min-1), peak and mean power output (W) might best be adjusted for differences in body mass (kg). A curvilinear power function model was shown to be theoretically, physiologically and empirically superior to the linear models. Based on the fitted power functions, the best method of scaling maximum oxygen uptake, peak and mean power output, required these variables to be divided by body mass, recorded in the units kg 2/3. Hence, the power function ratio standards (ml.kg-2/3.min-1) and (W.kg-2/3) were best able to describe a wide range of subjects in terms of their physiological capacity, i.e. their ability to utilise oxygen or record power maximally, independent of body size. The simple ratio standards (ml.kg-1.min-1) and (W.kg-1) were found to best describe the same subjects according to their performance capacities or ability to run which are highly dependent on body size. The appropriate model to explain the experimental design effects on such ratio standards was shown to be log-normal rather than normal. Simply by taking logarithms of the power function ratio standard, identical solutions for the design effects are obtained using either ANOVA or, by taking the unscaled physiological variable as the dependent variable and the body size variable as the covariate, ANCOVA methods.     

A family with RP3 type of X-linked retinitis pigmentosa: an association with ciliary abnormalities

Summary The results of linkage analysis in a family with X-linked retinitis pigmentosa (XLRP) are presented. Probe M27B (DXS255), localised to Xp11.22, was only loosely linked to XLRP, whereas pHOC3 (OTC), in the more distal Xp21.1 region, was tightly linked. In this family, the conditional probability of an RP3 locus (in Xp21.1–p11.4) was found to be 0.978 compared with 0.021 for an RP2 locus (in Xp11.4–p11.2). Risk assessment showed that 2 out of 4 at risk females showing no clinical abnormality have a high probability of being genetic carriers of XLRP. Some affected males have recurrent respiratory infections as a result of a condition indistinguishable from the immotile cilia syndrome; indeed, there is an association between XLRP and susceptibility to respiratory infections in the majority of affected males. The possibility that previously observed ciliary abnormalities in XLRP patients might be associated specifically with an RP3 locus abnormality is discussed.     

Evidence implicating heterozygous deletion of chromosome 7 in the pathogenesis of familial leukemia associated with monosomy 7.

Complete or partial monosomy 7 is a recurring cytogenetic abnormality in acute myelogenous leukemia (AML) and myeloproliferative syndromes (MPS) and is particularly common in patients with Fanconi's anemia and in secondary AML. A familial form of monosomy 7 has been recognized in which two or more siblings develop MPS or AML before age 20. We tested the hypothesis that a recessive cancer susceptibility locus on chromosome 7 was important in the pathogenesis of leukemia in familial monosomy 7 by determining the parental origins of the chromosome 7 retained in the bone marrows of three pairs of affected siblings. We found no overlapping region where all three pairs retained DNA derived from the same paternal or maternal chromosome. These data suggest that inactivation of a single allele of a putative tumor-suppressor gene may be sufficient to contribute to leukemic transformation in familial monosomy 7.     

Structural genes of glutamate 1-semialdehyde aminotransferase for porphyrin synthesis in a cyanobacterium and Escherichia coli

Summary In bacteria 5-aminolevulinate, the universal precursor in the biosynthesis of the porphyrin nucleus of hemes, chlorophylls and bilins is synthesised by two different pathways: in non-sulphur purple bacteria (Rhodobacter) or Rhizobium 5-aminolevulinate synthase condenses glycine and succinyl-CoA into 5-aminolevulinate as is the case in mammalian cells and yeast. In cyanobacteria, green and purple sulphur bacteria, as in chloroplasts of higher plants and algae a three step pathway converts glutamate into 5-aminolevulinate. The last step is the conversion of glutamate 1-semialdehyde into 5-aminolevulinate. Using a cDNA clone encoding glutamate 1-semialdehyde aminotransferase from barley, genes for this enzyme were cloned from Synechococcus PCC6301 and Escherichia coli and sequenced. The popC gene of E. coli, previously considered to encode 5-aminolevulinate synthase, appears to be a structural gene for glutamate 1-semialdehyde aminotransferase. Domains with identical amino acid sequences comprise 48% of the primary structure of the barley, cyanobacterial and putative E. coli glutamate 1-semialdehyde aminotransferases. The cyanobacterial and barley enzymes share 72% identical residues. The peptide containing a likely pyridoxamine phosphate binding lysine is conserved in all three protein sequences.     

Ribosomal protein S14 is not responsible for the Minute phenotype associated with the M(1)7C locus in Drosophila melanogaster.

Summary A locus associated with a severe Minute effect has been mapped at 7C on the X chromosome of Drosophila melanogaster. Previous work has suggested that this Minute encodes ribosomal proteins S14A and S141B. We have made a chromosomal deficiency that removes the S14 ribosomal protein genes, yet does not display the Minute phenotype. These data suggest that the S14 genes do not actually correspond to the Minute locus.     

Physiological Responses of Phytoflagellates to Dissolved Organic Substrate Additions. 2. Dominant Role of Autotrophic Nutrition in Pyrenomonas salina (Cryptophyceae)

The enhancement of algal growth by organic substrate assimilationis a common laboratory observation, yet few studies have addressedthe interaction of dissolved organic compounds and environmentalfactors for controlling the relative contribution of heterotrophyand autotrophy to the nutrition of these algae. The effectsof light intensity and glycerol addition on the growth, cellvolume, pigmentation, and carbon uptake of the facultative heterotroph,Pyrenomonas salina Santore, were examined. Glycerol additionto cultures growing at a limiting light intensity increasedthe growth rate, increased the average cell volume and cellularstarch content, decreased the cellular phycoerythrin to chlorophyll ratio, and had no effect on the CO₂ fixation rate cell^–1.Glycerol addition to cultures growing at a moderate light intensitythat was saturating for photo-autotrophic growth increased theaverage cell volume and cellular starch content but had no effecton the CO₂ fixation rate cell^–1. The results indicatethat autotrophy was the major process for carbon acquisitionduring the growth of P. salina, but that carbon acquisitionfrom glycerol catabolism also was used to partially supportgrowth of the alga at the limiting light intensity. In addition,glycerol presumably was used to fulfill the energy and/or reductantrequirements of the alga, and to increase the reserve carbohydrate(starch). ¹ Current address and address for correspondences: Horn PointEnvironmental Laboratories, University of Maryland, PO Box 775,Cambridge, Maryland 21613, U.S.A. (Received October 29, 1990; Accepted May 31, 1991)     

Polyphosphoinositol lipids inChlamydomonas eugametos gametes

InChlamydomonas eugametos gametes, phosphatidylinositol 4-phosphate (PtdInsP) and phosphatidylinositol 4,5-bisphosphate (PtdInsP₂) comprised 0.4 and 0.3% of the whole-cell phospholipids. They were concentrated in the plasma membrane around the cell body and were present in low concentrations in the flagellar membrane. When gametes were fed³²PO ₄ ^- , the label was rapidly incorporated into PtdInsP and PtdInsP₂ and only slowly incorporated into structural lipids such as phosphatidylethanolamine and phosphatidylglycerol. Similarly, when a pulse of³²PO ₄ ^- was chased with PO ₄ ^- , the label was rapidly lost from the polyphosphoinositol lipids but not from the structural lipids. The major fatty acids in the polyphosphoinositides were C-22 carbon polyenoic acids (70%). The significance of these results in relationship to intracellular signalling via inositol phosphates and Ca²⁺ is discussed.Abbreviations InsP₃ inositol 1,4,5-trisphosphate - mt^–/mt⁺ mating-type plus or minus - PtdA phosphatidic acid - PtdEtn phosphatidylethanolamine - PtdGro phosphatidylglycerol - PtdIns phosphatidylinositol - PtdInsP phosphatidylinositol 4-phosphate; - PtdInsP₂ phosphatidylinositol 4,5-bisphosphate - TCA trichloroacetic acid We thank Frank Schuring for Fig. 5A and Susan Kenter, Hans Kruisselbrink, Saskia Bijvank and Nelleke Corbett for their enthousiastic assistance.     

Demographic characteristics of cigarette smokers in the United States.

This research uses a multivariate log-linear examination of a national data set to analyze the combined influences of ethnicity, age, and sex on cigarette smoking status, not only for smokers but for former smokers and current nonsmokers as well. In general, we find that demographic differences in smoking vary across several dimensions. For instance, compared to females, males are more likely to smoke and to smoke heavily. The differences between male and female cessation rates vary with ethnicity; also, males and females tend to have different ratios of former smokers to light, moderate, and heavy smokers. Mexican-Americans who smoke generally smoke small quantities of cigarettes. And Blacks are as likely as other groups not to smoke at all, and less likely than Anglos to smoke heavily. This article discusses potential future mortality effects, intervention strategies, and directions for future research.     

Weights and hematology of wild black bears during hibernation.

We compared weights and hematological profiles of adult (greater than 3-yr-old) female black bears (Ursus americanus) during hibernation (after 8 January). We handled 28 bears one to four times (total of 47) over 4 yr of varying mast and berry production. Mean weight of lactating bears was greater (P less than 0.0001) than that of non-lactating females. White blood cells (P less than 0.05) and mean corpuscular volume (P = 0.005) also differed between lactating and non-lactating bears. Hemoglobin (P = 0.006) and mean corpuscular hemoglobin concentration (P = 0.02) varied among years; values were lowest during 1975, following decreased precipitation and the occurrence of a second year of mast and berry crop shortages in a three-year period. Significant (P less than 0.05) interaction between reproductive status (lactating versus non-lactating) and study year for hemoglobin, red blood cells, and packed cell volume, and increased mean corpuscular volume, suggested a greater nutritional challenge for lactating females compared to non-lactating females during the 1975 denning season. Our data suggest that hematological characteristics of denning bears may be more sensitive than weights as indicators of annual changes in nutritional status; however, other influential factors, in addition to mast and berry crop production, remain to be examined.