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L Black

Publications and source records attributed to L Black.

At least 55 records · Page 3Linked to original sources
PubMed1986

Densitometry and microchromatography compared for determination of the hemoglobin C and A2 proportions in hemoglobin C and hemoglobin SC disease and in hemoglobin C trait.

Using both densitometry and anion-exchange microchromatography, we measured hemoglobin C (Hb C) and Hb A2 proportions in 11 patients, eight of whom had Hb AC, two Hb SC, and one Hb CC. For one patient with Hb SC, we made the determinations before and after a transfusion. The mean (and SD) for the sum of Hb C + Hb A2 by densitometry and anion-exchange microchromatography for the nine patients with Hb AC and Hb CC were 45 (18) and 40 (18)%, respectively (p greater than 0.1, r = 0.98); for the three determinations involving the two Hb SC patients, the respective proportions were 40 (9.9) and 38 (6.6)% (r = 0.88). Electrophoretic analysis of microchromatographic eluates from the Hb AC and Hb CC patients showed that 6% of the absorbance of the late high-ionic-strength eluate was due to Hb C, which was responsible for the statistically insignificant difference between densitometric and chromatographic values for Hb C + A2 values. Electrophoresis on cellulose acetate of concentrated eluates of the Hb C + A2 fraction from the two Hb SC patients revealed no contamination by Hb S. Evidently, microchromatography can be used to determine Hb C + A2 in patients with Hb C or Hb SC disease or Hb C trait.

Anemia, Sickle Cell↗
PubMed1985

The 45-kb unit of major urinary protein gene organization is a gigantic imperfect palindrome.

The multigene family which codes for the mouse major urinary proteins consists of about 35 genes. Most of these are members of two distinct groups, group 1 and group 2. The group 1 and group 2 genes are organized in head-to-head pairs within 12 to 15 remarkably uniform chromosomal units or domains about 45 kilobase pairs (kb) in size. The 45-kb units are located on chromosome 4, and many of them are adjacent to each other. We propose that the 45-kb unit is a unit both of organization and of evolutionary change. In this study the homologies within the unit were observed by examining, in an electron microscope, heteroduplex and foldback structures made from cloned major urinary protein genes. These show that the 45-kb unit is a gigantic imperfect palindrome. Each arm of the palindrome contains two regions of inverted symmetry of 9.5 and 4.5 kb separated by a 3-kb nonsymmetrical region. We argue that the nonsymmetrical regions arose by a series of deletion events in the two arms of the palindrome. The center of the 45-kb unit is an 8-kb sequence without inverted symmetry flanked by the 9.5-kb regions, which contain the 4-kb genes and their immediate 5' and 3' flanking regions. The junction between adjacent 45-kb units is a 2- to 4-kb sequence without inverted symmetry flanked by the 4.5-kb regions. Some of the 45-kb units are arranged as direct tandem repeats. Others appear to be in inverted orientation with respect to a neighboring unit. Cloned major urinary protein genes show few incidences of the repetitive elements B1, B2, R, and MIF. Two elements, a B1 and an R, may be a constant feature of the 45-kb units. If so, in those cases in which the units are in tandem array, both of these elements will occur with a 45-kb periodicity. A comparison of corresponding parts of different 45-kb units shows that they differ because of a number of deletion or insertion events, particularly in the regions 3' to the genes.

Animals↗
PubMed1985

Guinea pig protection test as indicator of potency of oil emulsion foot-and-mouth disease vaccines.

A vaccine potency test is described involving virus challenge to six groups of 10 guinea pigs at five weeks after vaccination. Sixteen oil emulsion foot-and-mouth disease vaccines were so tested and nine retested after storage at 4 degrees C for up to 28.3 months. The results were compared with those of the routinely used oil emulsion vaccine potency test (protection afforded to eight pigs challenged 21 days after vaccination). When guinea pig estimates of 3 log2 PD50 or more were obtained, then, with one exception, the batches protected all or almost all pigs from challenge, but when the guinea pig estimates were less than 1 log2 PD50, the vaccines failed to protect five out of eight pigs. The sensitivity and reproducibility of the guinea pig method, established by repeated tests on two vaccine batches, seemed acceptable. The results suggested that guinea pig estimates might provide a suitable substitute for pig challenge potency tests because they reflected the potency of the vaccines, were likely to involve smaller standard errors and caused less discomfort to animals.

Animals↗
PubMed1984

Revaccination response of cattle as a function of the 140S foot and mouth disease antigen dose.

Fifty adult cattle were subdivided in 2 equal groups and inoculated with foot and mouth disease vaccines containing either 5 micrograms or 0.01 microgram of O1BFS 1860 140S antigen per 3 ml dose. Four months later they were subdivided into groups of 5 and injected with vaccines containing concentrations of the 140S antigen ranging from 54 micrograms to 7 ng per 3 ml dose. Bleedings were carried out periodically and the serum neutralizing antibody titres showed that the revaccination responses were influenced by the dose of 140S antigen in both the primary and secondary vaccinations. A linear log relationship was demonstrated between the anamnestic serum antibody log response and the dose of antigen in the secondary vaccines.

Animals↗
PubMed1984

The relationship between the 140S antigen dose in aqueous foot-and-mouth disease vaccines and the serum antibody response of cattle.

Groups of eight or 12 cattle were injected with dilutions of aqueous saponized vaccines containing 329 760 to 7 ng of 140S O1BFS 1860 strain foot-and-mouth disease antigen per dose. Four months later the animals were subdivided into groups of four and revaccinated with vaccines containing 329 760, 9160 and 42 ng of antigen per dose. Responses were established by taking serum samples from the animals periodically and examining these for neutralizing antibody activity. The results showed that after primary vaccination the dose of antigen in vaccines influenced the earliest time of protection, the peak antibody titres attained and probably, the duration of immunity. At 21 days after vaccination the log antigen-antibody response slope was linear between 7 and 9, 160 ng, with an inclination of 0.53, indicating that every doubling of the vaccine antigen dose produced an increase of 0.16 log10SN50 in the mean serum antibody titre. The secondary response was influenced by the antigen dose in the second vaccination and to a lesser extent by that in the first vaccination also.

Animals↗
PubMed1984

The relationship between serum antibody titres and protection from foot and mouth disease in pigs after oil emulsion vaccination.

In trials performed in Brazil, England and Germany, 765 pigs were challenged at one, three to four or 17 weeks after vaccination and their sera were titrated by macrocolour, microcolour or microcytopathic effects neutralization tests. Using O1 virus strains and challenge intervals of three to four weeks, significant correlations (P less than 0.01) were demonstrated between protection and serum neutralizing titres although the titres corresponding to given levels of protection varied with the titration method employed. The protective capacity of antiserum was confirmed by passive antibody transfer experiments. Retrospective analysis of 49 challenge tests showed that when the macrocolour test was employed, a group mean (n = 8) serum titre of 1.74 log10 SN50 corresponded with five out of eight (or more) protected from challenge in 92% of cases. The possibility of using serum titres as an alternative to challenge for oil emulsion vaccine potency tests is discussed.

Animals↗
PubMed1984

The effect of vaccination regimen on the transfer of foot and mouth disease antibodies from the sow to her piglets.

Four groups of pregnant sows were inoculated with type O1 foot and mouth disease (FMD) oil emulsion vaccine at various times before farrowing and samples of the sow's serum, colostrum and milk, and piglet's serum, collected during the first week after farrowing, were analysed for FMD virus neutralizing activity. No FMD neutralizing antibodies were detectable in the piglets serum at birth but they were present 1.5 h after suckling and peak titres were reached 1-3 days later. There was no significant difference between the antibody titres of colostrum samples collected from different teats at farrowing. However, similar samples collected 3 days later showed significant (P less than 0.005) fore to hind variation. The principal FMD virus neutralizing antibody class present in the sow's serum at farrowing and in their 3-day-old piglets was governed by the inoculation schedule employed. When the last vaccinations were given congruent to 30 days before farrowing (dbf) the predominant FMD virus neutralizing class was IgG. However, when the sows were vaccinated only congruent to 12 dbf the predominant class was IgM. A significant correlation was observed between the sow's serum titres and colostrum titres at farrowing (r = 0.90), and also between sows colostrum titres at farrowing and their 3-day-old piglets serum titres (r = 0.99).

Animals↗
PubMed1984

The effect of maternally derived antibodies on the response of calves to vaccination against foot and mouth disease.

Studies were carried out in South America to assess the effect of maternally derived antibody (MDA) on the responsiveness of calves to FMD vaccination. It was found that calves with MDA did not merely fail to respond to vaccination, but that their serum titres were depressed. This depression was proportional to the level of pre-existing MDA at the time of vaccination and following primary vaccination it persisted for a least 60 days. High MDA titres interfered with both primary and secondary responses. Animals with relatively low MDA titres were able to respond to vaccination, or at least to be sensitized so that on revaccination they showed a satisfactory response. The half-life of MDA was shown to be approximately 22 days, suggesting that under field conditions significant MDA titres are likely to persist for 4-5 months. A trial carried out in Brazil in which the primary course of two inoculations, 4 weeks apart, was initiated when the calves were 5-6 months of age, resulted in the reduction of FMD in the calf population from 11% to 0.9% over a 12-month period. The use of vaccination programmes of this type to lessen the incidence of FMD in young bovines is discussed.

Animals↗
PubMed1984

Effect of the sow vaccination regimen on the decay rate of maternally derived foot-and-mouth disease antibodies in piglets.

Three pairs of sows were vaccinated against foot-and-mouth disease (FMD) at various intervals before farrowing and samples of blood were collected from their piglets periodically for 70 days after birth. When the sows were vaccinated 12 to 13 days before farrowing the predominating FMD neutralising antibody at time of parturition was IgM and the observed half lives of the maternally derived antibodies in the piglets were short (four to eight days). However, when sows were last vaccinated 30 to 32 days before farrowing, the maternally derived FMD neutralising antibodies in the piglets were predominantly IgG and the observed half lives were seven to 21 days. These observed half lives for IgG were shown to be closely related to the period over which the maternally derived antibodies could be demonstrated and to the rate of increase of the piglet's blood volume over the same period. If corrections were made for increase in blood volume the decay rate of IgM antibodies in piglets was seven to 18 days while the decay rate for IgG was greater than 408 days. This result suggested that there was little or no IgG catabolism or excretion during the first 70 days of the piglet's life.

Aging↗
PubMed1983

Antibody response in pig nasal fluid and serum following foot-and-mouth disease infection or vaccination.

Nasal fluid and serum collected from pigs after exposure to live foot and mouth disease (FMD) virus or injection of single oil emulsion (w/o) or double oil emulsion (w/o/w) vaccines were examined for FMD neutralizing activity. After virus exposure the response profiles of serum and nasal mucus were similar to one another. In both, neutralizing activity rose to a peak at one to two weeks after exposure and then subsided slowly. After vaccination with either the w/o or w/o/w preparations a neutralizing response was demonstrable in the serum three to seven days after the first injection, and this was boosted by revaccinations 56 and 117 days later. The neutralizing activity was also detectable in nasal fluid seven days after the first vaccination, but subsequent revaccinations 56 and 117 days later provoked neutralizing titres which were no greater than those observed after the initial vaccination.

Animals↗
PubMed1983

Antibody response in bovine pharyngeal fluid following foot-and-mouth disease vaccination and, or, exposure to live virus.

Samples of pharyngeal fluid and serum were collected from cattle after exposure to live foot-and-mouth disease (FMD) virus (with or without prior vaccination) or after subcutaneous vaccination with inactivated virus. The pharyngeal fluid samples were examined for FMD neutralising activity and specific anti-FMD IgG, IgM and IgA antibodies. The neutralising activity of the serum was also monitored. A peak of neutralising activity which occurred in the pharyngeal fluid of unvaccinated cattle seven days after virus exposure corresponded to a rise in specific IgM and IgA antibodies. This peak appeared to be due to serum and tissue fluid escaping from the damaged mucosa during the acute inflammatory phase of infection. At later stages (20 to 60 days after virus exposure) the pharyngeal fluid neutralising activity corresponded to a rise in specific IgA antibodies, suggesting that active local antibody production was taking place. The pharyngeal fluid neutralising activity detected after revaccination with oil emulsion or aqueous vaccines, without exposure to live virus, corresponded to a rise in specific IgG and IgM antibody levels and this may have been due to serum transudation.

Animals↗
PubMed1982

Genetic/epidemiological findings in a study of smoking-associated tumors.

While the etiology of bronchogenic carcinoma remains enigmatic, an expanding array of carcinogenic pollutants in interaction with host susceptibility factors has been implicated. We have studied family histories of cancer in a consecutive series of cancer patients from two university oncology clinics in Nebraska. Particular attention has been given to carcinoma of the lung and other putative smoking-associated cancers (oral cavity, esophagus, urinary bladder, pancreas). Smoking histories were obtained for relatives of an overlapping series of patients with these tumor sites. Findings revealed that, although a significant cohort effect was observed with respect to smoking habits for both relatives of lung cancer probands and for relatives of probands with other smoking-associated tumors, a corresponding trend for lung cancer frequency was observed only for relatives of lung cancer probands. This result suggests the importance of host factors in combination with environmental exposures in determining lung risk. A cohort trend for lung cancer was also apparent among relatives of breast cancer probands, but not for relatives of colon cancer probands, suggesting the possibility of an intrinsic association between carcinomas of the breast and lung. We believe that further elucidation of host factor susceptibility in lung cancer may have important etiological and preventive implications.

Breast Neoplasms↗
PubMed1982

Antibody response of pigs to foot-and-mouth disease oil emulsion vaccine: the antibody classes involved.

Groups of three pigs were vaccinated with water-in-oil emulsion vaccine and revaccinated either 21 and 148 or 106 days later. Sera were taken periodically for six months and fractionated into heavy and light elements on sucrose density gradients. The heavier fraction contained IgM and the lighter fraction IgG and IgA. Neutralising antibodies were first detectable eight days after initial vaccination (dpiv), rose to a peak between 14 and 21 dpiv and persisted at relatively high titres until the time of revaccination. Neutralising antibody at eight dpiv was attributed to IgM but by 10 to 14 dpiv both IgM and IgG were involved. Thirty-five days (and later) after a single vaccination all the neutralising activity in the sera was due to IgG. The revaccinations produced an increment in the whole serum neutralising titres and in each case both IgM and IgG class antibodies were involved.

Animals↗
PubMed1981

Familial excess of cancer of the ovary and other anatomic sites.

In a family with a high incidence of cancer, the proband manifested early-onset colon cancer at age 39 years. His mother, her twin sister, and their daughters had ovarian carcinoma. In the proband's sibship, six of eight had cancer of differing anatomic sites. The susceptibility to ovarian carcinoma appeared to have been transmitted through the men; one was cancer free while two had cancer. Thus, eight close relatives had ovarian carcinoma. Examinations of 51 blood relatives failed to show cutaneous stigmata or congenital abnormalities of known hereditary cancer or precancer syndromes.

Adult↗
PubMed1979

Neonatal respiratory instability and infant development.

This study examines the relationships between neonatal sleep respiratory instability and infant development. A group of 122 full-term healthy infants was observed during a nap within the first and fourth weeks of life. During each nap, a continuous polygraphic recording was obtained of respiratory activity and extraocular movements. The relative frequency and average duration of apneic pauses (greater than or equal to 2 sec) in each testing session for an infant were employed to calculate a measure of respiratory instability (PSA4) previously found to be related to the occurrence of prolonged sleep apnea. 28 of the infants in this study were maintained at home on apnea monitors. The Bayley Scales of Infant Development were administered to each infant at approximately 9 months of age. Comparisons of infants with high versus low PSA4 values and of monitored versus unmonitored infants were not strongly distorted by imbalances in birth weight, sex, race, birth order, method of feeding, Sudden Infant Death Syndrome (SIDS) sibship, parental education, age at developmental assessment, and developmental tester. Those with increased respiratory instability (PSA4 greater than or equal to -0.04) within the first week of life averaged significantly lower in mental and psychomotor development. Utilization of home apnea monitors was not significantly associated with developmental scores.

Child Development↗