Prediction of responses in milk constituents to changes in the nutrition of dairy cows

Milk quotas, based on an average fat content, severely limit milk production on UK farms. Predictions of the time-course of lactation are incorporated into most computerized herd management programs but these models take no account of food inputs, body weight change or milk composition. Dynamic models are generally used to simulate metabolic pathways and, as such, have little direct relevance to commercial milk production. Dynamic models can be converted to an adaptive-predictive model that partitions food energy into milk and non-milk constituents. This paper reports the development of an adaptive-predictive model to partition food into milk and non-milk components. Additional functions further partition milk energy into the principal constituents, fat, protein and lactose.

A multipoint linkage map of the distal short arm of the human X chromosome

The distal portion of the short arm of the human X chromosome (Xp) exhibits many unique and interesting features. Distal Xp contains the pseudoautosomal region, a number of disease loci, and several cell-surface markers. Several genes in this area have also been observed to escape X-chromosomal inactivation. The characterization of new polymorphic loci in this region has permitted the construction of a refined multipoint linkage map extending 15 cM from the Xp telomere. This interval is known to contain the loci for the diseases X-linked ichthyosis, chondrodysplasia punctata, and Kallmann syndrome, as well as the cell-surface markers Xg and 12E7. This region also contains the junction between the pseudoautosomal region and strictly X-linked sequences. The locus MIC2 has been demonstrated by linkage analysis to be indistinguishable from the pseudoautosomal junction. The steroid sulfatase locus has been mapped to an interval adjacent to the DXS278 locus and 6 cM from the pseudoautosomal junction. The polymorphic locus (STS) DXS278 was shown to be informative in all families studied, and linkage analysis reveals that the locus represents a low-copy repeat with at least one copy distal to the STS gene. The generation of a multipoint linkage map of distal Xp will be useful in the genetic dissection of many of the unique features of this region.

Response of 7- to 15-month-old infants to sequential immunization with Haemophilus influenzae type b-CRM197 conjugate and polysaccharide vaccines

OBJECTIVE

To evaluate the immunologic potential of infants 7 to 15 months of age to respond to Haemophilus influenzae type b polysaccharide vaccine following immunization with H influenzae b oligosaccharide-CRM197 conjugate vaccine.

STUDY DESIGN

One hundred seventy-one infants, aged 7 to 15 months, were consecutively and alternatively assigned to one of three immunization protocols. Group 1 (n = 71) received three doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine, group 2 (n = 47) received two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine followed by one dose of H influenzae type b polysaccharide vaccine, and group 3 received one dose of H influenzae b oligosaccharide-CRM197 conjugate vaccine followed by two doses of H influenzae type b polysaccharide vaccine. Immunizations were given on day 0 and at 2 months and 6 months. Anti-H influenzae type b polysaccharide antibody levels were measured on day 0 and 2, 3, 6, 7, and 12 months after the study began.

RESULTS

Haemophilus influenzae type b polysaccharide vaccine given as a second dose stimulated an antibody rise but did so less effectively than H influenzae b oligosaccharide-CRM197 conjugate vaccine. Two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine were highly immunogenic; geometric means were 31 and 35 micrograms/mL in the 7- to 11-month and 12- to 15-month age groups, respectively. Following two doses of H influenzae b oligosaccharide-CRM197 conjugate vaccine, both immunization protocols resulted in (1) equally high geometric mean antibody levels 1 month after immunization and (2) similar geometric mean antibody levels 6 months after immunization.

CONCLUSIONS

Haemophilus influenzae b oligosaccharide-CRM197 conjugate vaccine induces antibody levels that would be expected to protect infants from initial invasion and primes the immune system for an anamnestic response. Our data indicate that if a booster immunization is needed, H influenzae type b polysaccharide vaccine could be an alternative to H influenzae b oligosaccharide-CRM197 conjugate vaccine.

Dihydropyridine receptor binding sites in the cardiomyopathic hamster heart are unchanged from control

An increase in the number of voltage dependent calcium channels has been implicated in the overload of calcium found in cardiac tissue of the cardiomyopathic hamster. We examined the binding of [3H]-(+)PN200110 to dihydropyridine receptors in cardiac muscle membranes from TO cardiomyopathic hamsters. When compared to random bred controls, there were no differences in either the Bmax or the KD for [3H]-(+)PN200110 binding using homogenates from 35 to 41-day-old TO cardiomyopathic hearts. In 8 to 9-month-old myopathic animals there were only small decreases in Bmax with no change in KD. We suggest that the calcium overload observed in cardiomyopathic hamster heart may not be due to an increased density of calcium channels as estimated by high affinity dihydropyridine receptor binding sites.

Hispanic Health and Nutrition Examination Survey: methodological considerations

The Hispanic Health and Nutrition Examination Survey (HHANES) was the first special population survey undertaken by the National Center for Health Statistics. The HHANES was designed to assess the health and nutritional status and needs of Mexican Americans, mainland Puerto Ricans and Cuban Americans. Data were collected using five data collection techniques: direct physical examinations, diagnostic testing, anthropometry, laboratory analyses, and interviews. Unlike other surveys conducted by the National Center for Health Statistics, the HHANES was not designed as a national survey. The HHANES was a survey of three Hispanic subgroups of the population in selected areas of the United States with a survey universe that included approximately 76 percent of the 1980 Hispanic-origin population in the United States. This article discusses statistical issues that should be addressed by researchers when analyzing HHANES data. Specifically, analysts need to account for the complex sample design, nonresponse bias, potential non-coverage bias, and the regional nature of the HHANES sample.

Families and networks among older inner-city blacks

These research findings compare the support networks of inner-city blacks and whites, 65 years and older, who were selected from hospital medical clinics. Both blacks and whites who are in need of help use formal supports. Blacks, however, have more active support networks than do whites despite the low incidence of support from spouses and children. These social resources result from mechanisms in black families that expand network membership through the creation of fictive kin.

Safety and immunogenicity of Haemophilus influenzae type b oligosaccharide-CRM197 conjugate vaccine in infants aged 15 to 23 months

A total of 268 infants aged 15 to 23 months received one dose of a vaccine composed of Haemophilus influenzae type b oligosaccharides covalently linked to the nontoxic diphtheria toxin variant CRM197 (HbOC; HibTITER). Side effects associated with vaccination were infrequent, transient, and mild. One month after a single vaccination, the anti-H influenzae type b capsular polysaccharide antibody concentration rose from a geometric mean prevaccination level of 0.20 microgram/mL to 13.77 micrograms/mL. Of these infants, 99% had a postvaccination level greater than or equal to 1.00 microgram/mL, a level associated with long-term protection. The immune response was long-lived: all of the children who were monitored 17 to 27 months after vaccination had concentrations greater than or equal to 1.00 microgram/mL. The anti-H influenzae type b capsular polysaccharide antibody generated was predominantly of the IgG isotype and IgG1 subclass. The immune sera had bactericidal activity in vitro and conferred passive protection in the infant rat meningitis model.

Within-person variance in biochemical indicators of iron status: effects on prevalence estimates

The effect of within-person variance on prevalence estimates from population distributions based on a single measurement was examined for hematologic and iron-status indicators collected in the Hispanic Health and Nutrition Examination Survey (HHANES). Within-person to between-person variance ratios (W:Bs) were estimated for 11 indicators by using data from 80 persons who provided blood twice in HHANES. Distributions of selected iron-status indicators from 20-44-y-old Mexican American females from HHANES were adjusted for within-person variance by using the W:B estimates, and prevalences of low values based on the original and adjusted distributions were compared. W:B were less than 1 for the majority of the indicators. Nonetheless, prevalences of low values from the original distributions were inflated when commonly used cutoff values were applied. Within-person variance in serum analytes needs to be controlled when the prevalence of a condition in populations is assessed.

Folate status of Mexican American, Cuban, and Puerto Rican women

The objective of this study was to estimate the prevalence of low serum and red blood cell (RBC) folate values of Mexican American (MA), Cuban (C), and Puerto Rican (PR) women examined in the Hispanic Health and Nutrition Examination Survey, 1982-1984. Serum and RBC folate were determined for all women aged 18-44 y by use of a radio-assay kit. The percent of women with low serum folate (less than 6.8 nmol/L) was 11.9% for MA, 10.1% for C, and 8.1% for PR. The prevalence of low concentrations of RBC folate (less than 363 nmol/L) was 7.8%, 16.7%, and 13.6% for MA, C, and PR, respectively. The percentages of women with reduced tissue stores of folate were 4.3% for MA, 6.0% for C, and 4.0% for PR. Years of education completed and poverty status did not significantly affect folate concentrations; however, the prevalence of low folate concentrations among users of vitamin or mineral supplements was significantly lower than it was among nonusers in selected subgroups.

Effect of dose and route of administration of thyroid releasing hormone (TRH) on the concentration of prolactin (PRL) and thyroxine (T4) in cyclic gilts

Our objective was to examine the ability of thyroid releasing hormone (TRH) to stimulate not only the release of the thyroid hormones, but also prolactin (PRL) in the female pig. An experiment was conducted to determine the effect of dose and route of administration of TRH on the concentration of PRL and thyroxine (T4) in cyclic gilts. Six gilts were injected with 0, 5, 25, 125, and 625 micrograms TRH and fed 0, 5, 2.5, 12.5 and 62.5 mg TRH. Gilts received TRH once daily. During the 10-day treatment period, route of TRH administration alternated between i.v. injection and feeding. The dose of TRH progressed from the lowest to the highest. Blood samples were taken prior to TRH injection and thereafter at 15-min intervals for 3 hr. Sampling continued for an additional 3 hr at 30-min intervals when TRH was fed. Concentrations of PRL and T4 were determined by radioimmunoassay. Intravenous injection of gilts with 125 and 625 micrograms TRH resulted in an increase in PRL from 0 to 15 min (P less than .05). All doses of TRH given i.v. elevated T4 over a 2-hr period (P less than .01). TRH failed to increase PRL when TRH was fed (P greater than .5). The feeding of 62.5 mg TRH elevated T4 from 0 to 6 hr (P less than .01). Thus, TRH injection increased PRL rapidly and T4 gradually. When TRH was fed, only a gradual elevation in T4 was observed. We conclude that TRH can elicit the release of both PRL and T4 in the cyclic gilt, but magnitude and duration of the PRL and T4 response depends on the dose and route of TRH administration.

Rationale of feeding systems for lactating dairy cows

Manipulations of the lactation cycle are achieved through nutritional regimens and generally result in a restriction of the physiological lactation cycle. Most models of lactation used in management programmes only describe the average time course of lactation for groups of cows on a given feeding regimen. This is inadequate for the variety of feeding systems in use on British farms. In the present paper several existing models of lactation have been critically evaluated. An integral equation approach has been developed to rationalize experimental observations and currently accepted biological concepts.

Safety and immunologic response to Haemophilus influenzae type b oligosaccharide-CRM197 conjugate vaccine in 1- to 6-month-old infants

A Haemophilus influenzae type b oligosaccharide-CRM197 conjugate (HbOC) vaccine was evaluated for safety and immunogenicity in 432 infants 1 to 6 months of age. In a multicenter study involving 10 sites in six states, infants were vaccinated with three 10-micrograms doses of HbOC at 2-month intervals. Side effects associated with vaccination were mild, transient, and occurred in fewer than 2% of the subjects. More than 90% of infants of all ages responded after two doses, and more than 98% had anti-H influenzae type b capsular polysaccharide (HbPs) antibody levels greater than or equal to 1 microgram/mL after three doses. One month after the third vaccination, the geometric mean anti-HbPs antibody levels were 16.84, 26.23, and 29.11 in infants initially vaccinated at 1 to 2, 3 to 4, and 5 to 6 months of age, respectively. A long-term antibody response was observed; more than 80% of these infants had anti-HbPs levels greater than or equal to 1 microgram/mL at 2 years of age. The HbOC generated an immune response characteristic of a protein antigen; IgG anti-HbPs antibodies of IgG1 subclass predominated and the response could be boosted. The immune sera killed H influenzae type b when evaluated in an in vitro bactericidal assay. The data indicate that HbOC safely primed and boosted the immune system of young infants, providing long-lasting protective levels of anti-HbPs antibodies.

Histamine receptors in human fibroblasts: inositol phosphates, Ca2+, and cell growth

Histamine stimulated inositol phosphate formation by human skin fibroblasts. The effect of histamine was reduced but still readily apparent in the absence of extracellular Ca2+. Histamine caused a transient increase in intracellular free Ca2+ as detected by indo-1 and fura-2 fluorescence studies on cell populations and on individual cells. Similar increases were observed in the absence of extracellular Ca2+, indicating that the effect was primarily due to mobilization of Ca2+ from intracellular stores, presumably by inositol trisphosphate (IP3). The effects of histamine on phosphoinositide metabolism and intracellular Ca2+ were inhibited by pretreatment of the cells with phorbol esters, suggesting that the histamine receptor in fibroblasts is subject to feedback regulation by protein kinase C. Histamine inhibited the incorporation of [3H]-thymidine into DNA. The effects of histamine on inositol phosphate formation, intracellular Ca2+, and thymidine incorporation were blocked by the H1 receptor antagonist mepyramine. Our results indicate that human skin fibroblasts have H1 receptors coupled to the formation of inositol phosphates and mobilization of intracellular Ca2+. We suggest that this H1 receptor also mediates a block of the cell cycle and that histamine may play a physiological role in the regulation of fibroblast proliferation.

A critique of the caregiving literature

In this critical review of the recent caregiving literature, we identify several methodological problems. Specifically noted are the variable and often confusing definitions of the caregiver, the lack of specification of needs, overrepresentation of self-selected samples, and the absence of attention to the total support network. We conclude that future researchers should focus on the total support process in later life, rather than on a single caregiver, so that policy can best be designed to mesh the informal and formal support systems.

Inhibition of human skin fibroblast proliferation by histamine and phorbol esters is mediated by protein kinase C

The proliferation of human skin fibroblasts in culture was examined using a [3H]thymidine incorporation assay. Histamine inhibited thymidine incorporation with an IC50 of about 0.2 microM. This effect was blocked by the H1 receptor antagonist mepyramine but not by the H2 receptor antagonist cimetidine. Protein kinase C activators, including several phorbol esters and mezerine, also inhibited thymidine incorporation. The IC50 for beta-phorbol 12,13-didecanoate was less than 0.1 nM. The alpha-isomer of this compound was inactive. Long-term treatment of cells with the beta-isomer eliminated the ability of both histamine and phorbol ester to inhibit thymidine incorporation, presumably due to downregulation of protein kinase C. Our results suggest that histamine H1 receptors are linked to activation of protein kinase C and that activation of this enzyme leads to an inhibition of cell proliferation.

The Kmod blood group phenotype in a healthy individual

This report describes a healthy blood donor whose red cells have weakened expression of Kell blood group antigens. Kell antigen activity could not be detected by flow cytometric analysis and was demonstrable only by sensitive serologic techniques. As with normal-strength Kell antigens, reactivity could be abolished by treatment with 2-aminoethylisothiouronium bromide (AET). The donor's red cells have Kx antigen activity. Other commonly tested blood group antigens (MNSs, Rh, P1, Lewis, Duffy, and Kidd systems) appear normal. Clinical and serologic examination showed that this case is different from previously described examples of modified Kell expression. The propositus's phenotype has remained unchanged for 19 months, which suggests that it is not a transient condition. However, family studies provide no evidence that it is inherited. A 93-kD protein, which reacted weakly by Western blot with rabbit antibody to Kell protein, was isolated from the propositus's red cells by immunoprecipitation. This finding was not reproduced in subsequent studies, which suggests that the quantity of Kell protein recovered was at the threshold level detectable by the technique used. The red cell phenotype is categorized as Kmod, of which this is the first example reported in a healthy individual.

Development of human embryonic and fetal dermal vasculature

This report summarizes recent advances in the understanding of the structure and organization of the microvasculature in developing human skin. Previous observations suggested that the skin contains no blood vessels as late as eight weeks estimated gestational age (EGA). Computer reconstructions, in conjunction with light and transmission electron microscopy (TEM), however, demonstrated that specimens as young as 35-45 d show a level of vascular complexity previously unknown. The computer reconstructions showed that the vasculature was organized in one or two planes parallel to the epidermis. A simple, single plane was evident in specimens 40-50 d EGA, whereas specimens 50-75 d EGA showed two planes. Fewer vessels were continuous throughout the tissue sample in the younger specimens compared with the older specimens. Superior views highlighted the continuities and connections of vessels. The younger specimens showed more discontinuous segments of vessels when compared with the network established in the older specimens. In the earliest specimens examined morphologically (35-40 d), simple, capillarylike vessels were morphologically identifiable in presumptive dermis. The samples studied by TEM revealed detailed structure of the vessel wall including extreme attenuations and projections, plasmalemmal vesicles, and junctions similar to adult endothelial cells. Little or no basal lamina surrounded the vessel. The basal lamina first appeared in the form of amorphous deposits and eventually thickened and became continuous. By the end of the first trimester, the basal lamina still lacked the organization of adult cutaneous arterial and venous segments. These findings suggest that the major vascular organization of the dermis is defined in the first trimester of development.

Comparison of human and chimpanzee Kell blood group systems

Kell antigens on chimpanzee (Pan troglodytes) red cells were determined using specific human alloimmune and murine monoclonal antibodies. After avoidance of interspecies reactions, chimpanzee red cells were found to react with most Kell system antibodies. The chimpanzees had phenotypes similar to those of humans. The main difference was that all of 27 chimpanzee red cell samples tested were of the K:6, -7, phenotype, while in humans most are K:-6, 7. The most common chimpanzee Kell blood group phenotype was K:-1,2,-3,4,5,6,-7,11,12,13,14, 15,18,19,22. Murine monoclonal anti-K2 and -K14 immunoprecipitated a 97-kD protein from chimpanzee red cells and a 93-kD protein from human red cells. Enzymatic deglycosylation yielded proteins of about 79 kD for humans and 77 kD for chimpanzees. Both human and chimpanzee Kell proteins reacted equally well on Western blots with polyclonal rabbit antibody to human Kell protein, which indicated close homology.

Effect of change of diet on the mineral composition of rumen fluid, on magnesium metabolism and on water balance in sheep

1. The effects of four diets on water intake, rumen fluid outflow-rate, rumen pH and mineral metabolism were studied in wether sheep. The diets were barley and hay, flaked maize and hay, dried grass and frozen grass. 2. Experimental periods were of 12 d duration, and plasma magnesium concentrations were lower at the end of treatment periods when the grass diets were given and were significantly different (P less than 0.05) at 11.00 and 20.45 hours. Also, the concentration was significantly lower with the dried-grass diet than with the frozen-grass diet (P less than 0.05). 3. The concentration of Mg in rumen fluid centrifuged at 30,000 g (ultracentrifuged) varied with the diet. Maximum concentrations (tmax) were reached 4 h later on the grass diets than on the hay and concentrate diets. In the latter case tmax coincided with that for calcium, potassium, chloride and ammonia. At this time sodium and phosphate were at a minimum. The concentration of Mg in ultracentrifuged rumen fluid was negatively correlated (r -0.89) with pH, which was significantly higher (P less than 0.01) at all times on the grass diets. This relation was also reflected in the apparent availability of Mg. 4. Total water intake on the frozen grass was about twice that on the barley and hay diet. The outflow rate of liquid from the rumen was higher on the frozen grass than on the other three diets. 5. The proportion of absorbed Mg excreted in urine was significantly influenced by diet.

Iron status: prevalence of impairment in three Hispanic groups in the United States

Little is known about the iron status of Hispanic groups in the United States. Data from the Hispanic Health and Nutrition Examination Survey were used to estimate the prevalence of impaired Fe status for persons aged 5-74 y from three Hispanic groups: Mexican Americans (MAs), Cubans, and Puerto Ricans; prevalences were also calculated for non-Hispanic whites (NHWs) and non-Hispanic blacks (NHBs) using data from the second National Health and Nutrition Examination survey. A three-variable model called the MCV model was used to assess impaired Fe status. Prevalences based on the MCV model did not differ between Hispanic groups. Differences between Hispanics and non-Hispanics occurred only among 20-44-y-old females, where MAs had a higher prevalence than NHWs or NHBs. With this exception, these Hispanic groups do not appear to be at greater risk of impaired Fe status than non-Hispanics.