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Biomedical subjects

J L Sullivan

Publications and source records attributed to J L Sullivan.

At least 127 records · Page 7Linked to original sources
PubMed1993

Comparison of digestibility, nutritive value, and storage characteristics of different forms of cottonseed in diets fed to lactating dairy cows.

Thirty-two Holstein cows averaging 70 d postpartum were used to compare digestibility of whole short staple cottonseed (SS) to whole Pima (WP), coarsely cracked Pima (CrP), and ground Pima (GP) cottonseeds and their effects on lactational performance. Cottonseed was fed at 15% of diet DM. Milk and solids-corrected milk (SCM) yields were higher for cows fed GP than for cows fed CrP or WP but were not different from yields of cows fed SS. Feed efficiency (SCM/DMI) was higher for cows fed GP and SS than for those fed WP. Milk of cows fed GP was lower in stearic acid but higher in linoleic and linolenic acids than milk of cows fed SS. Whole seeds passing into the feces (percentage of consumed) were higher for WP (12.3%) than for SS (6.2%). Total tract digestibility of ether extract was lower for WP than for other diets. Digestibilities of other nutrients were not different. To test storage characteristics, samples of cottonseed were incubated at 32 degrees C and 30% relative humidity for 0, 10, 20, and 30 d, or stored at ambient temperatures in covered buckets for 9 mo. No differences in amount of free fatty acids between incubated samples were noted, and only CrP stored in buckets for 9 mo was significantly higher in free fatty acids than initial or frozen seed. No differences in aflatoxin were detected, and levels were very low. Milk yield of cows fed GP diets was similar to that of cows fed SS diets and slightly higher than those of cows fed CrP or WP diets. Processing the Pima seed increased feed efficiency.

Animal Feed↗
PubMed1993

Effect of protein quality and evaporative cooling on lactational performance of Holstein cows in hot weather.

Twenty-four Holstein cows in midlactation during summer in southern Arizona were fed diets supplemented with a combination of blood, fish, and soybean meals (high quality protein) or corn gluten meal (low quality protein). Diets were balanced for CP content and estimated ruminal protein degradability, but they differed in Lys concentration (.98 vs. .59% of DM). Milk yield for the 56-d trial was higher by 11% for cows fed high than for cows fed low quality protein and higher by 9% for cows receiving evaporative cooling plus shade than for cows receiving shade alone. Milk fat and protein yields also were greater for high than for low quality protein and for evaporatively cooled plus shade than for shade treatments. Intake of DM tended to be higher for cooled cows but was unaffected by protein source. Cooled cows had lower rectal temperatures (38.6 vs. 39.1 degrees C) and respiration rates (64 vs. 82/min) than noncooled cows. Interactions between protein quality and cooling method were not statistically significant; however, cooled cows fed high quality protein had higher milk yield than noncooled cows. Digestibility of DM was higher for the low than for the high quality diet, but CP digestibilities were not different. Cows fed supplemental protein of higher Lys content were more productive.

Animal Feed↗
PubMed1993

Performance of dairy cows fed short staple, Pima, and cracked Pima cottonseed and feed characteristics.

Compared with short staple cottonseed, Pima cottonseed was higher in CP, ether extract, and oleic acid and lower in NDF, ADF, and linoleic acid. Pima cottonseed had greater bulk density, but short staple cottonseed had stronger seed coat strength; Pima cottonseed contained more of the (-)-gossypol isomer than short staple cottonseed. Lactating Holstein cows were fed whole short staple cottonseed, whole Pima cottonseed, and cracked Pima cottonseed at 15% of dietary DM for 70 d after a pretrial covariate period. The DMI was not significantly different among treatments, but cows fed whole Pima tended to yield less milk than those fed short staple and less FCM than those fed cracked Pima. Feed efficiency was improved by processing Pima cottonseed. Milk fat content was higher for whole and cracked Pima than for short staple cottonseed; gross feed efficiency was greatest for cows fed cracked Pima cottonseed. Whole cottonseed in feces was highest for whole Pima, intermediate for short staple, and negligible for cracked Pima cottonseed. Concentrations of milk stearic acid were lower, and linoleic acid higher, for cows fed cracked Pima than for cows fed short staple cottonseed. Total tract digestibility of ADF was least on the cracked Pima cottonseed diet, and ether extract digestibility was higher on cracked than on whole Pima cottonseed diets.

Animal Feed↗
PubMed1992

Silent human immunodeficiency virus type 1 infection: a rare occurrence in a high-risk heterosexual population.

A group of 58 heterosexual female partners (FP) of human immunodeficiency virus type 1 (HIV-1)-seropositive hemophiliacs was studied by conventional diagnostic methods such as enzyme-linked immunosorbent assay (ELISA) and Western blot analysis to examine whether any had acquired HIV-1 infection through sexual transmission. A subset of 29 FP were asked to answer a detailed questionnaire concerning their health, use of "safer sex" techniques, and other risk factors for HIV-1 infection. They also had additional blood drawn for CD4 cell analysis, viral cultures, nef, gag, and env immunoblots, and polymerase chain reaction (PCR) analysis to assess the occurrence of "silent" HIV-1 infection in a high-risk seronegative population. Among the 58 FP, three were found to be HIV-1-seropositive on first testing, with no new seroconversions occurring with subsequent testing in the remaining 55. Two seropositive FP had the additional testing and were found to have positive viral cultures, as well as positive PCR results. All of the seronegative FP (n = 24) who had additional testing were negative in viral culture, had negative immunoblots, and had no HIV-1 nucleic acid sequences detected by PCR. Thus, in this population, silent HIV-1 infection appears to be a rare occurrence and antibody testing seems to correlate with the more sensitive techniques of PCR and viral cultures.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Diagnosis of vertical human immunodeficiency virus type 1 infection by whole blood culture.

The qualitative and quantitative performance of a human immunodeficiency virus type 1 (HIV-1) whole blood culture method was assessed for use in the diagnosis of vertical HIV-1 infection. This method requires < 1 mL of whole blood and allows for the quantification of blood virus load. HIV-1 was isolated from 36 (95%) of 38 whole blood specimens from 27 HIV-1-infected children compared with 0 of 16 whole blood specimens from 16 uninfected children. HIV-1 titers were significantly higher in severely symptomatic children (2450 TCID/mL) than in less symptomatic children (179 TCID/mL). This simple quantitative culture assay may be useful for the early diagnosis of vertical HIV-1 infection, the assessment of blood virus load, and the evaluation of antiretroviral therapies.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Relationship between platelet monoamine oxidase B activity and alleles at the MAOB locus.

Genetic variations in monoamine oxidase (MAO)-B activity have been proposed to have a contributory role in several neurologic and psychiatric diseases. Variations in activity could affect rates of degradation of exogenous amines, including toxins, precursors of toxins (like 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), or false transmitters, and of endogenous amines, such as neurotransmitters. In this study a highly polymorphic (GT)n repeat element was used to mark alleles at the MAOB locus. The MAOB allele status and levels of platelet MAO-B activity were determined for 41 control males. No correlation was noted between specific alleles and levels of MAO-B activity in this sample set. This suggests that the structural gene for MAOB is not usually the primary determinant of activity levels in platelets.

Adult↗
PubMed1992

Factors affecting response of cows to biweekly injections of sometribove.

Seventy-eight lactating Holstein cows (18 primiparous and 60 multiparous) were used to study certain factors affecting response in milk yields to biweekly injections of bST. Cows were intramuscularly injected with placebo or with 500 mg of bST every 14 d for 36 wk beginning 60 d postpartum. Primiparous cows responded less to bST than did multiparous cows. Cows were separated into three yield groups within each treatment based on pretreatment yield: low (27.0 kg/d), medium (32.0 kg/d), and high (39.0 kg/d). Response of low yielding cows to bST was numerically greater than that of medium or high yielding cows, but there was no significant interaction between treatment and pretreatment milk yield. Individual cow index for milk yield was used as a measure of genetic potential of cows, which were divided into two index groups: high cow index (greater than -23 kg) and low cow index (less than -23 kg). Cows in the high index group showed significantly higher milk yields than the low index group during treatment, but treatment by cow index interaction was not significant, suggesting that cows of widely ranging genetic potential respond similarly to bST. Response of cows to bST in mid to late lactation was slightly greater than in early lactation (15.9 and 10.6% vs. 17.8%, respectively), but no significant interaction of treatment by days postpartum was noted. Finally, even though cows treated with bST exhibited slightly higher rectal temperatures during the hot summer months, no significant difference in milk yield response to bST was noted during periods of moderate versus high ambient temperatures.

Animal Feed↗
PubMed1991

Limiting dilution analysis of cytotoxic T lymphocytes to human immunodeficiency virus gag antigens in infected persons: in vitro quantitation of effector cell populations with p17 and p24 specificities.

The presence of cytotoxic T lymphocytes (CTL) to the gag antigens of human immunodeficiency virus (HIV) has been described in infected populations. We found that the majority of this immune response as measured in bulk CTL assays of unstimulated peripheral blood mononuclear cells (PBMC) is directed against the p24 component of the p55 gag precursor protein. Using limiting dilution analysis of this effector cell population we confirm that the majority of activated gag-specific CTL circulating in the PBMC of infected hemophilic patients are directed at p24 determinants and are present at frequencies of 1/36,000 to 1/86,000 lymphocytes. By performing in vitro stimulation after limiting dilution, the precursor population of gag-specific CTL are characterized and quantitated. HIV gag-specific CTL precursors are identified at frequencies of 1/1700 to 1/17,000 lymphocytes and are made up of cells with both p17 and p24 specificities. No HIV gag-specific CTL precursor cells are identified in the PBMC of HIV-uninfected individuals. These studies demonstrate that CTL directed at both p17 and p24 determinants make up the cellular immune repertoire in HIV-infected individuals but that only the p24-specific CTL are routinely found in an activated state in the circulation.

CD8 Antigens↗
PubMed1991

Quantitation of human immunodeficiency virus in vertically infected infants and children.

We used a quantitative human immunodeficiency virus, type 1 (HIV-1) culture method to determine whether there is a relationship between the amount of replicating virus in the blood of vertically infected children and the relatively short latency period before development of symptomatic disease in these children. HIV-1 titers were determined by end point dilution in the peripheral blood mononuclear cells and the plasma of 30 infected (CDC class P1 and P2), 36 indeterminate (CDC class PO), and 19 uninfected (CDC class P3) infants and children born to HIV-1 seropositive mothers. HIV-1 was recovered from 35 (90%) of 39 PBMC cultures and 23 (60%) of 38 plasma cultures of infected patients not receiving antiretroviral therapy. The mean HIV-1 titers tended to be higher in patients with more advanced disease (P2, D, E, or F: 1760 TCID/10(6) PBMC, 460 TCID/ml plasma) than in asymptomatic or mildly symptomatic patients (P1; P2, A or C: 90 TCID/10(6) PBMC; 60 TCID/ml plasma). A poor correlation between HIV-1 titers and serum p24 antigen levels was found. No correlation was observed between viral titers and relative or absolute numbers of CD4 lymphocytes. Plasma virus titers were lower in 9 patients receiving zidovudine (ZDV) therapy (mean 2 TCID/ml) than in untreated patients of similar clinical status. The viral titers measured in the blood of vertically infected infants and children were on the same order of magnitude as the viral titers measured in HIV-infected adults. We conclude that the relatively rapid progression to symptomatic disease of the majority of vertically infected patients is not due to a higher load of replicating virus in blood.

AIDS-Related Complex↗