Search PubMed⌕ Search

Biomedical subjects

A Black

Publications and source records attributed to A Black.

At least 109 records · Page 6Linked to original sources
PubMed1988

An unusual case of stridor.

A case is reported in which stridor was the presenting symptom of acute superior vena cava obstruction, after attempted insertion of a Hickman catheter.

Catheterization, Central Venous↗
PubMed1988

Screening for cystic fibrosis: a four year regional experience.

A four year regional screening programme to detect cystic fibrosis using measurement of immunoreactive trypsinogen is described. During this period 60 infants were diagnosed; 34 by screening, 12 born with meconium ileus, and 14 not identified by the screening assay but who presented with clinical symptoms at a later age, giving an incidence of cyst fibrosis in the region during this time of 1/1807. Screening has resulted in earlier detection of cystic fibrosis in many infants, thus allowing treatment to be instituted at an early age, and genetic counseling offered to the parents. There were a number of false positives and false negatives with the immunoreactive trypsinogen screening assay. In addition, eight infants who were sweat tested at an early age had a sweat sodium concentration of less than 70 mmol/l, although they were subsequently shown to have cystic fibrosis. These results confirm other published data showing that sweat sodium results may be low in very young infants with cystic fibrosis. At the time of diagnosis seven (20%) of the infants identified by screening were totally asymptomatic and several additional children had symptoms of such a type that the diagnosis of cystic fibrosis had not been considered at the time of screening. Despite the problems experienced it has been decided to continue screening.

Age Factors↗
PubMed1988

Monoclonal antibodies show Listeria monocytogenes in necropsy tissue samples.

Stable mouse monoclonal hybridoma cell lines secreting antibodies against Listeria monocytogenes were produced. Antibodies from two of these cell lines (designated CL2 and CL17) have been partially characterised. The specificities of these antibodies were assessed using indirect immunofluorescence antibody tests and L monocytogenes (166 strains) grown in vitro, other species of Listeria (21 strains), and bacteria from 14 other genera (87 strains). The antibodies were found to be specific for Listeria, and when used in combination, reacted with almost all strains of L monocytogenes. A simple and rapid direct immunofluorescence technique was developed, and the presence of L monocytogenes was shown in necropsy tissue from three patients where listeriosis had been confirmed by isolation of the bacterium. Bacteria were also confirmed using one of these antibodies in necropsy tissue from one further patient in whom listeriosis was suspected, but not confirmed by the cultivation of L monocytogenes.

Adult↗
PubMed1987

Novel cell cycle-related nuclear proteins found in rat and human cells with monoclonal antibodies.

Monoclonal antibodies which react specifically with the nuclei of interphase cells recognized three nuclear antigens with molecular weights of 110,000 (p110), 85,000 (p85), and 18,000 (p18). p110 and p85 were found in eight tumor cell lines but were not found in resting lymphocytes. p18 was found in resting lymphocytes as well as the tumor cell lines. Protein p85 appeared in phytohemagglutinin-stimulated lymphocytes in the G1 phase and protein p110 appeared in the S phase. p110 and p85 were localized to the extranucleolar chromatin while p18 was distributed throughout the nucleus and was determined by microscopic and DNase digestion studies to be DNA associated. The anti-p110 antibody recognized a component of the DNA polymerase alpha 2 complex. Three novel nuclear proteins were identified using monoclonal antibodies. Two of these proteins (p110 and p85) are proliferating cell nuclear and nucleolar antigen-like while the third (p18) is not cell cycle dependent.

Animals↗
PubMed1987

Novel nucleolar antigens in autoimmune disease.

Antinucleolar antibodies are of interest in 2 important areas, namely, autoimmune diseases and specific products involved in the "mitogenic cascade." The former have delineated a series of novel nuclear and nucleolar elements including the recently described proliferating cell nuclear antigens (PCNA), some of which are present in the nucleolus only at specific times in the G1-S phase of the cell cycle. Important new proteins such as "fibrillarin" (34 kD/pI 8.5) and a 125 kD nucleotide containing protein have been identified with antinucleolar antibodies. Protein p145 is a nucleolar PCNA that is present in growing and dividing cells but not in normal resting tissues. Antinucleolar antibodies offer powerful tools, not only for identification of specific nucleolar proteins important in the cell cycle, but also for purification of their genes and analysis of mechanisms of gene control that operate the "time windows" of the cell cycle.

Amino Acid Sequence↗
PubMed1986

Neurologic syndrome associated with low levels of vitamin E in primary biliary cirrhosis.

A 41-yr-old woman with primary biliary cirrhosis developed weakness and wasting in proximal muscles, areflexia, and decreased proprioceptive and vibratory sensation. Investigations revealed law serum levels of vitamin E and electromyographic and muscle biopsy changes consistent with a neuropathy. Sural nerve histology demonstrated axonal dystrophy with patchy demyelination. These features closely resemble a neurologic syndrome associated with chronic cholestatic liver disease and vitamin E deficiency in children. Adults with chronic cholestasis may also be susceptible to neurologic damage from prolonged malabsorption of vitamin E.

Adult↗
PubMed1986

Translocation of 239Pu in mice following inhalation of sized 239PuO2.

This study showed that when SAS/4 mice were exposed to sized 239PuO2 only about 0.5% of the 239Pu was translocated from lung to other organs. The fraction of 239Pu translocated appeared to be independent of the particle size of the administered 239PuO2 within the range of AMADs investigated (0.8-2.2 microns). The distribution of translocated 239Pu was similar to that observed with other species in that most of the activity was associated with the lung-associated lymph nodes followed by bone and liver. The fraction of 239Pu translocated was comparable to that found in studies with rats (ICRP72) but less than that found in more extended studies with beagle dogs.

Aerosols↗
PubMed1985

Heart rate break point may coincide with the anaerobic and not the aerobic threshold.

Recently, Conconi et al. (4) proposed that the point where heart rate departs from linearity in an incremental exercise test is a good predictor of the aerobic threshold (AeT, i.e., the exercise intensity at which blood lactate concentration increases systematically above resting levels). We hypothesized that this heart rate break point (BrP) is a better predictor of the anaerobic threshold (AnT, i.e., the exercise intensity at which blood lactate concentration shows a rapid rise during an incremental test). To test this hypothesis, 11 subjects with different levels of conditioning were tested on a cycle ergometer using a progressive incremental exercise protocol. Heart rate from EKG tracings and blood samples for lactate determination were taken every minute. The results showed the following significant correlation coefficients when the variables were expressed in watts: AeT and AnT = 0.92; AeT and BrP = 0.89; AnT and BrP = 0.97. The AeT was significantly lower than the BrP (166.4 +/- 52.6 W and 234.5 +/- 69.5 W). There was no significant difference between the AnT and BrP (240.0 +/- 67.1 W and 234.5 +/- 69.5 W). Another group consisting of 16 subjects performed two tests to evaluate the reproducibility of the BrP. Although a ventilatory AnT (defined as a consistent decrease in the fraction of expired CO2) was noted in all the tests, eight subjects failed to demonstrate a BrP in at least one of the evaluations, even though post-exercise blood lactate levels and peak heart rates were consistent with a maximal effort.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

cDNA of the immunoglobulin kappa chain of an Epstein-Barr virus-transformed human lymphoid cell line: partial sequence determination and bacterial expression.

We report the isolation, nucleotide sequence determination, and bacterial expression of a partial cDNA for the immunoglobulin kappa chain from the Epstein-Barr virus-transformed human lymphoid cell line GM131. The cDNA, cloned in pBR322 by use of oligo(dG) X oligo(dC) tails, yields two Pst I fragments of 250 and 600 base pairs (bp). Various restriction enzyme fragments of the cDNA were subcloned in the vectors M13 mp10 and M13 mp11 for sequence analysis. As a result of instability of the 250-bp M13 subclones, the base sequence of the 250-bp Pst I fragment could not be determined. The 600-bp Pst I fragment contains coding sequences for part of the variable (V) region (residues 78-95) and all of the joining (J) (residues 96-108) and constant (C) regions (residues 109-212) and extends 148 bp into the 3' flanking region. Although the C- and 3'-flanking-region sequences are identical to germ-line sequences, the J-region sequence does not correspond to any of the five human germ-line J regions. The sequence is most similar to that of J4, with three base changes resulting in one silent mutation and two amino acid substitutions, at residues 103 (Lys----Tyr) and 106 (Ile---Met). The silent mutation appears to be the result of RNA splicing between the J and the C regions. The V-region sequence differs from published V-region germ-line sequences at several codons and from the more common amino acid sequences at two positions, residues 91 and 93. At these positions, histidine residues are found in place of the more common tyrosine and serine, respectively. None of the four amino acid substitutions observed for the GM131 kappa-chain are unique, suggesting that the changes, which most likely contribute to antigenic specificity, are compatible with antibody structure and function. The 600-bp Pst I fragment was subcloned in two prokaryotic expression vectors, pATH11 and pUC8. In both instances, a kappa-chain fusion protein detectable by immunoblotting was produced.

Amino Acid Sequence↗
PubMed1984

Effects of previous exercise on the ventilatory determination of the aerobic threshold.

To study the effects of previous submaximal exercise on the ventilatory determination of the Aerobic Threshold (AeT), 16 men were subjected to three maximal exercise tests (standard test = ST, retest = RT, and test with previous exercise = TPE ) on a cycle ergometer. The protocol for the three tests consisted of 3 min pedalling against 25 W, followed by increments of 25 W every minute until volitional fatigue. TPE was preceded by 10 min cycling at a power output corresponding to the AeT as determined in ST, followed by a recovery period pedalling against 25 W until VO2 returned to values consistent with the initial VO2 response to 25 W. AeT was determined from the gas exchange curves (ventilatory equivalent for O2, fraction of expired O2, excess of VCO2, ventilation, and respiratory gas exchange ratio) printed every 30 s. The results showed good ST X RT reliability (r = 0.89). TPE showed significantly higher AeT values (2.548 +/- 0.44 1 X min-1) when compared with ST (2.049 +/- 0.331 X min-1) and RT (2.083 +/- 0.30 1 X min-1). There were no significant differences for the sub-threshold respiratory gas exchange ratios among the trials. The sub-threshold VO2 response showed significantly higher values for TPE at power outputs above 50 W. It was concluded that the performance of previous exercise can increase the value for the ventilatory determination of the AeT due to a faster sub-threshold VO2 response.

Adult↗
PubMed1984

Cannabis use and sensation-seeking orientation.

Cannabis use and its relationship with sensation-seeking orientation was investigated in 48 college and university students of both sexes. Users and nonusers were matched for sex, age, and education. Cannabis users scored higher on all the four subscales of the sensation-seeking scale (SSS). Analysis of covariance controlling for the use of alcohol, cigarettes, and LSD decreased the level of significance between the user and nonuser groups on all the subscales and the total SSS scores; however, the differences between the user and nonuser remained significant on the disinhibition subscale and the total SSS scores.

Adult↗
PubMed1984

Retention of 239Pu in the mouse lung and estimation of consequent dose following inhalation of sized 239PuO2.

The retention of 239Pu in the lungs of SAS/4 mice following inhalation exposure to sized 239PuO2 particles is described. When the initial alveolar deposition (IAD) was less than 200 Bq, retention of 239Pu could be described by a two-component exponential expression, about 90% being cleared with a half-time of about 40 days and the remainder with a half-time of about 150 days. Similar amounts of 239Pu were retained up to 3 months with IADs greater than 800 Bq, but clearance was impaired thereafter, the half-time of the second component increasing to about 720 days. The retention of 239Pu was independent of the particle size of the administered 239PuO2. Studies of the retention of 239Pu by individual lobes indicated that there were intrinsic interlobar differences which were enhanced at higher IADs. Lung clearance was also studied by the measurement of 239Pu in feces excreted by groups of mice in the period immediately prior to sacrifice. The estimation of radiation dose to lung is discussed.

Aerosols↗