Vitamins E and A, and proximate composition of whole mice and rats used as feed.

Six mouse size categories, and four rat sizes were analysed. Vitamin E concentration was similar among all mice classes (mean = 43.8 +/- 13.4 IU/kg dry). Rat pinkies contained 470.4 +/- 158.7 IU/kg dry while older rat size classes did not differ (mean = 138.0 +/- 67.2 IU/kg dry). Vitamin A concentrations increased with age in both mice and rats, from approximately 16,700 IU/kg (crawler mice) to approximately 300,000 IU/kg in adults (dry matter basis). Fuzzy and crawler mice did not differ nutritionally; proximate composition in mice was similar to previously reported data for rodents. Rat proximate composition did not differ among any size category (13% ash, 28% crude fat, 56% crude protein), except water decreased with age (79-65%).

An ultrasound survey of gallbladder disease among Mexican Americans in Starr County, Texas: frequencies and risk factors.

The Mexican-American population of south Texas has been shown previously to have elevated frequencies of gallbladder disease, based on medical history. In the present study, ultrasonography was employed to screen 1004 randomly selected individuals aged 15 to 74 years. Among women, the frequency of previous cholecystectomy was 10.0%; the frequency of stones on ultrasound was 12.2%. In men, the respective frequencies were 1.7% and 6.3%. Highest frequencies of gallbladder disease occurred among those aged 45 years or above: 40.2% and 19.2% among women and men, respectively. Non-insulin-dependent diabetes mellitus, obesity, and hypertension were also markedly elevated in this population. Overall, more than 40% of the population had either gallbladder disease, non-insulin-dependent diabetes, obesity, or hypertension. Among those older than 45 years, 70% had one or more of these chronic conditions. Examining the associations of gallbladder disease with other chronic diseases or measures of lipids, lipoproteins, and apolipoproteins demonstrates that factors predictive of or associated with cholecystectomy are different from those for gallstones by ultrasound. Diabetes and obesity show the strongest associations with cholecystectomy among women under 45 years (women with diabetes being 6.8 times as likely to have had a cholecystectomy than those without diabetes). Testing an extensive array of lipid-related measures resulted in no clear patterns, with the possible exception of alpha-lipoprotein and related measures. That the Mexican-American population is relatively young and experiencing extremely rapid growth indicates that the burden of chronic disease in general and gallbladder disease in particular will increase dramatically in the coming years.

Effects of the apolipoprotein E polymorphism on levels of lipids, lipoproteins, and apolipoproteins among Mexican-Americans in Starr County, Texas.

Genetic variability has been implicated as a significant contributor to the variation in levels of lipids, lipoproteins, and apolipoproteins (apos) through a variety of direct and indirect investigations. Among the direct investigations, apo E has been shown to be polymorphic and to explain a small but statistically significant proportion of the variability in cholesterol. The apo E polymorphism was typed in 964 randomly selected Mexican-Americans from Starr County, Tex., and its effects determined on levels of cholesterol, triglycerides, total high density lipoprotein (HDL) cholesterol, subfractions (HDL2 and HDL3), alpha- and beta-lipoprotein cholesterol, low density lipoprotein (LDL) cholesterol, and apos A-I, A-II, B, C-II, C-III, and E. Effects are reported for the entire sample and in each of three groups, namely, premenopausal females, postmenopausal women, and males. In the entire sample, significant effects were observed on cholesterol, beta-lipoprotein cholesterol, LDL, apo B, and apo E. There is evidence for significant physiological interaction of the apo E polymorphism effect in females by menopausal status. This is most evident for apo E levels, in which 5.9% of the variability in the entire sample is explained by the apo E polymorphism. In premenopausal females, however, the polymorphism accounts for 27.5% of the variability. In postmenopausal women and males, there is no significant effect. It is shown that the apo E polymorphism can be treated as a two-locus, two-allele system. Doing so identifies substitutions in amino acid position 158 as the mediators of most of the observed effects of this polymorphism.

Lipoprotein and apolipoprotein levels among Mexican-Americans in Starr County, Texas.

Mexican-Americans represent the single largest component of the US Hispanic population and have been shown to bear a disproportionate burden of chronic disease. A representative sample of 1,004 Mexican-Americans aged 15-74 years from Starr County, Tex., was recruited for this study. Each subject was provided a detailed physical evaluation that included measurement of fasting levels of cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol and its subfractions (HDL2 and HDL3) alpha- and beta-lipoprotein cholesterol, and low density lipoprotein cholesterol. Apolipoproteins A-I, A-II, B, C-II, C-III, and E were determined for approximately 550 of these individuals. Age- and sex-specific mean levels and percentile cut points are presented. The distributions of lipoproteins are quite similar to those of the general population except for consistently higher triglycerides in males and females and lower HDL cholesterol levels in females. These findings are consistent with the high frequency of obesity. Comparative age- and sex-specific data for the apolipoproteins are not widely available. Where such data exist, apolipoprotein levels observed in the Mexican-American population tend to be similar to or lower than the comparative data.

Apolipoprotein A-IV protein polymorphism: frequency and effects on lipids, lipoproteins, and apolipoproteins among Mexican-Americans in Starr County, Texas.

Apolipoprotein A-IV phenotypes were determined by reprobing immunoblots initially typed for the apolipoprotein E polymorphism on a representative sample of Mexican-Americans from South Texas. Typings on 331 individuals gave frequency estimates of 0.928, 0.066, 0.003, and 0.003 for alleles 1, 2, 3, and 4, respectively. To evaluate the effects of this polymorphic variability on lipid-related measures, mean levels between phenotypes were tested for equality following adjustment for age, sex, and body mass index. Analyses of levels of cholesterol, triglycerides, total high density lipoprotein, and its subfractions, low density lipoprotein, alpha and beta lipoproteins and apolipoproteins A-I, A-II, B, C-II, C-III, and E demonstrate that the A-IV genetic variability contributes minimally to normal variation of these quantitative factors in the population. Examination of the rare types, however, indicates the possibility of large metabolic effects whose follow-up may be useful for elucidating the metabolic roles of apolipoprotein A-IV.

Electrophoretic analysis of liver neuraminidase-1 variation in mice and additional evidence concerning the location of NEU-1.

Neuraminidase-1 (NEU-1) is one of two neuraminidase isozymes which can be detected electrophoretically in mouse liver extracts. The inheritance of variation in NEU-1 and the linkage relationships of the gene controlling this variation were studied through a backcross analysis involving the SM/J and MA/MyJ inbred strains, and by examination of NEU-1 phenotypes in three congenic strains: B10.SM, B10.SM(22R) and B10.RVB. The data indicate that NEU-1 is controlled by Neu-1, a gene previously identified by its effect on total liver neuraminidase activity in whole tissue homogenates. Analysis of the congenic strains revealed identical low activity (SM/J-type: Neu-1a/Neu-1a) NEU-1 phenotypes in all three strains. This indicates that Neu-1 lies in the segment of the SM/J-derived H-2 region that is common to all three strains: H-2E alpha to H-2D. In addition, we examined the relationship between NEU-1 and phenotypic variation in liver acid phosphatase (AP; for which a new typing method is described) and linkage order among several other enzyme-coding genes linked to H-2. In all animals that could be scored confidently for AP, the NEU-1 and AP phenotypes were concordant, adding support to the hypothesis that both phenotypes are controlled by Neu-1. Recombination rates among six H-2-linked marker loci were unexpectedly low, but were sufficient to verify the position of Upg-1 as the telomeric flanking marker relative to Glo-1, H-2 (C4), Neu-1 (Apl), Ce-2 and Pgk-2.

Genetically controlled variation of "acid" beta-galactosidase detected in Rattus norvegicus by isoelectric focusing.

Two genetically variant forms of rat "acid" beta-galactosidase were found to differ in isoelectric point and pH dependence, but not in thermostability or sensitivity to inhibition by p-mercuribenzoate (PMB). The results of two backcrosses and an intercross indicated that the isoelectric focusing phenotypes are controlled by two codominant alleles at a single autosomal locus, for which we propose the name Glb-1. No significant linkage between Glb-1 and albino (LG I), brown (LG II), or hooded (LG VI) was observed. Strain-specific differences in total levels of kidney beta-galactosidase were detected, but it is not yet known whether the variation is controlled by genes linked to Glb-1. Experiments in which organ homogenates were incubated with neuraminidase indicated that the genetically variant forms do not result from differences in sialylation, though sialylation does appear to be largely responsible for the presence of multiple bands within each phenotype and for differences in the banding patterns of beta-galactosidases derived from different organs. The beta-galactosidase present in the bands used for Glb-1 typing resembles human GM1 gangliosidase (GLB1) with respect to pH optimum, substrate specificity, and susceptibility to inhibition by PMB. It also appears that Glb-1 is homologous with the Bgl-e locus of the mouse. In rats as in mice the genetically variant bands of beta-galactosidase are active at acid pH and have relatively high isoelectric points. In both species these bands are readily detectable in kidney homogenates, and can be revealed in homogenates of liver or spleen following treatment with neuraminidase. The presence of the same beta-galactosidase bands in homogenates of rat kidney and small intestine as well as in neuraminidase-treated homogenates of liver and spleen suggests that the Glb-1 variants differ by one or more point mutations in the structural gene for "acid" beta-galactosidase.

Location of the gene for theta antigen in the mouse. III. The position of Thy-1 relative to Lap-1 and Mpi-1.

The position of the Thy-1 (theta cell surface antigen) locus on chromosome 9 of the mouse was determined relative to the biochemical markers Lap-1 (leucine arylaminopeptidase) and Mpi-1 (mannosephosphate isomerase). Four-point backcrosses using both male and female heterozygotes showed that the order of these loci is Lap-1--Thy-1--Mpi-1. By observing the segregation of alleles at the Mod-1 (cytoplasmic malic enzyme) locus, which is known to lie distal to these three markers, it was possible to show that Lap-1 is at the centromeric end of this gene group. The overall map for this portion of chromosome 9 as determined by these crosses is: Lap-1--5--Thy-1--7--Mpi-1--14--Mod-1.

Location of the gene for theta antigen in the mouse. II. Three-point crosses place Thy-1 in proximal region of chromosome 9.

Males of a partially inbred mouse stock homozygous for cw and d were crossed to AKR/ABom females. Progeny obtained by backcrossing heterozygous F1 females to cw d/cw d males were analyzed for the markers cw, Thy-1, d, and Mod-1. Three- and four-point recombination data are consistent with the map: cw--29--Thy-1--12--d--5--Mod-1, in which cw is nearest to the centromere. These recombination data are discussed in relation to previous multiple-point recombination studies of chromosome 9.

The expression of theta-like antigen by rat peripheral lymphocytes: serologic and functional studies.

AKR/Cum mice (Thy-1b = thetaC3H) immunized with nucleated cells from WF rat thymus, Peyer's patches, peritoneal exudate, mesenteric lymph nodes, blood, bone marrow, or spleen produced antibodies cytotoxic for ADR/J (Thy-1a = thetaAKR) but not for AKR/Cum thymocytes. The specificity of these antibodies for the Thy-1.1 (theta-AKR) antigen was confirmed by tests using thymocytes from backcross mice segregating at the Thy-1 locus. This result suggested that the rat lymphocyte antgen cross-reactive with Thy-1.1 was expressed by at least some members of each of the rat lymphoid cell populations tested. AKR/Cum mice immunized with killed rat cells also produced anti-Thy-1.1 antibodies; thus indicating that further differentiation of the injected cells was not a prerequisite for the anti-Thy-1.1 response. Unexpectedly, about 9% of unimmunized adult AKR/Cum males were found to be producing antibodies against Thy-1.1. To our knowledge, natural antibodies of this specificity have not been previously reported. Finally, it was found that peritoneal exudate cells taken from WF rats previously immunized with EL-4 mouse leukemia cells were neither killed nor functionally inactivated by treatment with anti-Thy-1.1 antibodies and complement.

Occurrence of a theta-like antigen in rats.

A rat antigen system parallel to the mouse theta system has been described(*) All rat strains tested expressed an antigen cross-reactive with the theta-AKR specificity of mice while none cross-reacted strongly with theta-C3H. The rat antigen may be demonstrated by either absorption or direct complement-mediated killing of rat thymocytes. Patterns of organ distribution and developmental appearance in the nervous system of rats also parallel those previously reported for theta in mice.