Heparin-induced thrombocytopenia and thrombosis: detection and specificity of a platelet-aggregating IgG

A 46-year-old female who died as a result of thrombocytopenia associated with multiple arterial occlusions and septicemia while on heparin therapy was found to have a platelet-aggregating factor present in several plasma samples and in a sample of serum. This factor was subsequently shown to be an IgG with aggregating properties toward normal platelets that were enhanced by, but not dependent on, the presence of heparin. Further studies showed that heparin was unlikely to have acted as a hapten in initiating the IgG production but that its role was significant in aggravating the ensuing arterial thrombosis. The necessity of substitution of heparin with alternative anticoagulant/antithrombotic therapy to avoid the worst sequelae of this potentially catastrophic syndrome is discussed.

Leukaemic promyelocytes and normal bone marrow cells release a passive sodium transport modifier (inhibitin)

Previous studies have shown that leukaemic immature cells, specifically promyelocytes but not mature leucocytes, contain and release an inhibitor of ouabain-insensitive sodium transport (inhibitin). In the present study, medium from cultured leukaemic promyelocytes significantly reduced the ouabain-insensitive sodium efflux from erythrocytes, whereas medium from the same cell line which had been made to differentiate did not have this effect. Culture medium from normal bone marrow cells (containing promyelocytes) also significantly (P less than 0.001) reduced ouabain-insensitive sodium efflux. These data suggest that inhibitin is secreted by primitive but not by mature leukaemic cells and normal bone marrow cells.

TEMPORAL VARIATION OF THE MATING SYSTEM IN A NATURAL POPULATION OF JACK PINE

Mating system parameters of a northern conifer, Pinus banksiana Lamb., were estimated from allozyme polymorphisms. Seeds analyzed were obtained from serotinous cones of 30 individuals and represented four independent fertilizations in 1975, 1976, 1977 and 1978. Results indicated that a mixed mating system model, with a mean effective outcrossing rate of 88 ± 0.047%, described the mating system of this stand. However, there was an approximately linear increase in the apparent selfing rate from the oldest (1975) to the newest (1978) crop. Two hypotheses could account for these observations. First, there may have been changes in the mating system during the 4-yr period, but linearity of the differences observed in this study may have been due to chance. These changes were, however, independent of the variability of the observed pollen pool. This indicated that they were not a result of different proportions of outcrossed zygotes directly observed. Second, there could have been a more or less constant amount of selfing, followed by a differential loss of viability of selfed and outcrossed zygotes during the period of storage in the cones. Under this hypothesis, selfed zygotes are at a selective disadvantage relative to outcrossed zygotes. No differences in the mating system could be demonstrated among the three crown strata of this stand. There was significant interlocus heterogeneity in the filial generation genotypic distributions and in the estimated outcrossing rates, reflecting the complex nature of forces that can affect single-locus estimates. There was evidence of some additional inbreeding, possibly due to family structures in the stand; however, this was a minor component of the total inbreeding.

Effects of repeated dose nitrazepam and lormetazepam on psychomotor performance in the elderly

The daytime psychomotor performance of 12 healthy subjects of mean age 81.4 years was examined in a double-blind crossover study following single and repeated nightly doses of nitrazepam 5 mg, lormetazepam 1 mg, and placebo. Accuracy of performance on the Gibson spiral maze was unaffected by both drugs. On a reciprocal tapping task, speed was similarly unaffected. However, while neither drug significantly impaired accuracy on reciprocal tapping after the first dose, nitrazepam, but not lormetazepam, significantly reduced overall accuracy after seven consecutive doses, an effect consistent with drug accumulation.

Segregation of allozymes in megagametophytes of viable seed from a natural population of jack pine, Pinus banksiana Lamb

Segregation ratios of allozymes in haploid female gametophytes obtained from viable seed were studied in a natural population of jack pine, Pinus banksiana. Stability of these ratios was assessed for three levels of the sexually reproductive crown as well as for four years of natural fertilization. Analyses of observed segregation ratios of four of five polymorphic isozyme loci showed good correspondence to the overall 1∶1 ratios expected for simple Mendelian inheritance. Allozymes of glucose-6-phosphate dehydrogenase did not segregate in the expected 1∶1 ratio. In addition, there were significant deviations from the expected segregation ratio for all the loci at some sampling positions on individual trees. Heterogeneity of segregation among trees, strata and years could be the result of pollen pool heterogeneity, segregation distortion and/or recessive lethal and semi-lethal gene combinations resulting in early embryo abortion. These types of segregation deviations in viable seed can affect the estimation of allele frequencies from bulked samples of a small number of individuals, the inference of heterozygosity/homozygosity of parental trees, and estimates of selfing rates.

Changes in hypnotic usage in residential homes for the elderly: a longitudinal study

The use of hypnotic drugs in 25 local authority homes for the elderly was recorded on a 1-day point prevalence study following a 6-mth monitoring programme involving all new admissions. From a total population of 1114 residents 390 (35%) were taking hypnotics on the night of the survey, showing a slight increase from similar surveys carried out in 1980 and 1981. The proportion of residents receiving hypnotics within each home varied from 0.0 to 61.8%. Correlation with levels of usage in the previous surveys was low, suggesting that pattern of hypnotic usage may change considerably over time within individual homes. Of the 156 residents who were admitted as permanent residents during the 6-mth period preceding the survey, 56 (35.9%) had been taking hypnotics on admission. Both the results of the drug monitoring programme and the survey show an association between hypnotic usage and source of admission: residents admitted from hospital being more likely to be taking sleeping tablets. A considerable change was found in the type of hypnotic currently prescribed with an increased preference being shown for short half-life hypnotics. A higher proportion of residents also were prescribed lower doses of hypnotics than previously, suggesting an increased awareness of the risks associated with hypnotic use in the elderly.

Isolation of a sodium transport inhibitory factor, inhibitin, from cultured leukemic promyelocytes

Previous studies have shown that leukemic blood contains a factor that has an inhibitory effect on bidirectional sodium transport in erythrocytes. This study was designed to isolate this factor from cultured leukemic promyelocytes. An extract from the promyelocytes reduced significantly (P less than 0.001) the ouabain-insensitive sodium efflux rate, from 0.096 +/- 0.009 to 0.056 +/- 0.003 SD. Using the inhibition of ouabain-insensitive sodium transport in erythrocytes as an assay to identify the factor, we ran the crude promyelocyte extract through Sephadex G-25 and G-10, with an intermediate ion-exchange step on DE-32, and finally subjected the active fraction to reverse-phase high-performance liquid chromatography. The specific inhibitory activity of the final fraction was 180-fold higher than that of the crude promyelocyte extract. The inhibitory activity could be destroyed by acid hydrolysis and by enzymatic digestion with several proteases but not by heating at 80 degrees C for 30 min; these characteristics suggest that the active factor, called inhibitin, is a peptide. Inhibitin is released by immature myeloid cells but not by differentiated white cells or by leukemic lymphocytes. It has no effect on potassium influx but inhibits sodium/sodium exchange in erythrocytes.

Release of an active sodium transport inhibitor (ASTI) from rat hypothalamic cells in culture

To investigate the hypothesis whether the hypothalamus releases an active (ouabain-sensitive) sodium transport inhibitor, we cultured hypothalamic and cortical cells from day 17 fetal rats. Culture media from hypothalamic cells reduced the total erythrocyte sodium efflux rate constant from 0.487 +/- (SE) 0.014 to 0.408 +/- 0.013 (P less than 0.001), and the ouabain-sensitive rate constant from 0.305 +/- 0.015 to 0.240 +/- 0.016 (P less than 0.01). Hypothalamic media also showed a dose-dependent displacement of [3H]-ouabain-binding to erythrocyte membranes. Neither cortical nor conditioned media (incubated without cells) had any effect. Various well-characterized hormones of hypothalamic origin failed to inhibit sodium efflux rate constant. These studies demonstrate that fetal rat hypothalamic cells contain and release a factor which inhibits sodium transport in human erythrocytes.

Erythrocyte sodium pump activity in human obesity

In an attempt to resolve the prevailing confusion about erythrocyte sodium pump activity in obesity, we measured sodium-potassium-ATPase, ouabain-inhibitable (active) sodium efflux rate constant and intracellular sodium concentration in erythrocytes from 107 non-obese and obese subjects, with a body-mass index ranging from 17 to 54 kg X m-2. All the three independently measured variables were not significantly different between the two groups and no correlations were found between these three indices and body-mass index. The expression of ATPase activity in units of membrane protein allowed our previous data to be compared with this study and other reports. Our studies and most of the published reports suggest that there is no difference in erythrocyte sodium-potassium-ATPase and sodium transport between the vast majority of obese and non-obese subjects, but there is a subgroup of obese subjects (about 5%) with abnormally high erythrocyte sodium pump activity. The variable treatment of data from this subgroup and the small numbers of obese subjects studied by various investigators are largely responsible for the conflicting results about erythrocyte sodium pump activity.

Native type II collagen-induced arthritis in the rat. Studies of the humoral response to collagen at the cellular level

In rats immunized with native type II collagen the number of lymphocytes secreting anti-type II collagen antibodies was enumerated in the lymph nodes using the direct hemolytic plaque assay. Arthritic rats had more lymphocytes, more plaque forming cells to native type II collagen and higher levels of serum IgM antibody to native type II collagen than nonarthritic rats. In vitro incubation of lymphocytes with native type II collagen before the plaque assay greatly increased the number of plaque forming cells from arthritic rats but not from nonarthritic rats. These findings suggest that arthritic rats had greater reactivity to native type II collagen and were less able to control the humoral response to collagen than were nonarthritic rats.

Diffuse endobronchial polyposis following a titanium tetrachloride inhalation injury

We report a case of diffuse endobronchial polyps contributing to continued respiratory failure in a patient 5 wk after titanium tetrachloride inhalation injury. After the institution of corticosteroid therapy, the total number and size of remaining polyps were markedly reduced at which time the subject was successfully weaned from the ventilator. Follow-up bronchoscopy at 2 months, 5 months, and 1 yr postinjury revealed gradual but complete resolution of all polyps accompanied by improvement in the patient's obstructive airways disease. This delayed complication of inhalation injury has been previously reported as a complication of thermal respiratory injury, and may be an important contributing factor in prolonged or late respiratory failure in burn patients.

Acquired factor XI inhibitors in two patients with hereditary factor XI deficiency

Two patients with hereditary factor XI deficiency developed inhibitors following plasma transfusions. Neither had severe spontaneous bleeding. The patients' plasmas neutralized both factor XI in plasma, purified factor XI, and purified factor XIa. The inhibitor in both patients' plasmas adsorbed to Protein A-Sepharose. The inhibitors eluted from Protein A-Sepharose were partially neutralized by kappa and lambda light chain antisera indicating that they were polyclonal IgG antibodies. Both inhibitors markedly decreased adsorption of factor XI to glass surfaces. The cleavage of factor XI by trypsin was unaffected by the inhibitors. The lack of severe spontaneous bleeding in both of these patients strongly suggests that an alternate coagulation mechanism bypassing factor XI must compensate for this severe defect.

Reliability of a test of cardiovascular fitness

The reliability of a simple, cheap and portable test for estimating cardio-respiratory fitness (the Canadian Home Fitness Test) was assessed by the test/retest method. Substantial intra-subject variation was demonstrated which was between 49% and 85% of the observed group variation. At the 95% confidence level, this intra-subject variation represented an error of between 19.2% and 25.9% on the key measurement (mean post-exercise heart rate) depending on the degree of work done. The probable reason for this poor repeatability was observer error and this is discussed. It is concluded that this test is not suitable for either clinical or population research and alternative methods, such as historical review of physical activity, may be more useful.

A passive sodium transport inhibitory factor (inhibitin) released from leukaemic promyelocytes in culture

Previous studies have shown that myeloid leukaemic blast cells contain a heat stable factor which inhibits bidirectional sodium transport in normal erythrocytes. This study was undertaken to establish whether leukaemic promyelocytes in culture secrete this factor. Two cell-lines of leukaemic promyelocytes (HL-60 and JR) were grown and culture media from both reduced significantly the ouabain-insensitive sodium efflux rate constant, whereas conditioned culture medium (incubated like the cells in culture) had no inhibitory effect. Promyelocyte extract reduced significantly (P less than 0.01) the total sodium efflux rate constant from 0.393 +/- 0.030 (SD) to 0.311 +/- 0.060, and ouabain-insensitive efflux rate constant from 0.131 +/- 0.008 to 0.079 +/- 0.009 (P less than 0.001). The inhibitory factor was heat stable (80 degrees C for 30 min) and it inhibited sodium efflux through a pathway which was not inhibited by ouabain or frusemide. These studies suggest that leukaemic promyelocytes secrete the previously identified passive sodium transport inhibitory factor.

Effect of loprazolam and of triazolam on psychological functions

Twelve poor sleepers of mean age 52 years performed 2 h of laboratory tests three times on 1 day during each week of nightly intake of loprazolam 0.5 mg, loprazolam 1 mg, triazolam 0.5 mg, or continued placebos. Only in the mornings did loprazolam 1 mg cause impairment in manual dexterity and card-sorting, and triazolam 0.5 mg in manual dexterity. Using difference from baseline, withdrawal of either drug after 3 weeks was associated with poorer subjective quality of sleep than following continuing placebos. The rate of spontaneous complaints (including accidents) associated with the drugs was as informative as formal testing.

Enhancement (by native type II collagen) of the humoral immune response to native type I collagen in the rat

Both native type II collagen and rabbit IgG were good immunogens in the rat when emulsified in incomplete Freund's adjuvant but native type I collagen and denatured type II collagen were not. Both native type II collagen and rabbit IgG had an enhancing effect upon the production of antibodies to native type I collagen when rats were immunised with a mixture of native type I collagen and either of these immunogens but denatured type II collagen did not have this effect. These immunogens, however, did not enhance the production of antibodies to ovalbumin when emulsified with it. Although both native type II collagen and rabbit IgG showed this enhancing effect with native type I collagen, only rats immunised with native type II collagen or mixtures containing native type II collagen developed arthritis. Thus, a specific immune response to collagen rather than this enhancing effect appears to be necessary for the induction of arthritis.

IgG subclasses in collagen-induced arthritis in the rat

Using a solid-phase double-antibody radioimmunoassay IgG antibodies to native bovine type II collagen were measured as total IgG and as subclasses of IgG (IgG1, IgG2a, IgG2b, IgG2c ) in arthritic and non-arthritic Sprague-Dawley rats. Statistically significant differences were observed between arthritic and non-arthritic animals for IgG1, IgG2a, IgG2b and total IgG. The significance of these results and their possible relevance to the human disease are discussed.

Effects of two benzodiazepines on the speed and accuracy of perceptual-motor performance in the elderly

The daytime performance efficiency of 12 elderly subjects of average age 81.5 years (range 75-96 years) was examined in a cross-over study following lormetazepam 1 mg, nitrazepam 5 mg, and placebo capsules nightly for 7 nights. Performance was assessed on the Gibson spiral maze, and a reciprocal tapping task. In both tasks the speed and the accuracy of performance were independently measured. Performance testing sessions were conducted on the morning following the first, and the morning following the seventh dose of each of the three experimental treatments. Performance on the Gibson spiral maze showed no significant effect of either of the active drugs. On the reciprocal tapping task, speed was similarly unaffected by both drugs. However, while neither drug significantly affected overall accuracy after the first dose, nitrazepam but not lormetazepam significantly impaired overall accuracy after seven consecutive doses. This difference between nitrazepam and lormetazepam was significant. Further analyses showed nitrazepam consistently to be associated with impaired accuracy at both intermediate and high levels of task complexity. Lormetazepam, on the other hand, was associated with impairment only at the highest level of task complexity. The overall pattern of impairment associated with nitrazepam, but not with lormetazepam, was consistent with drug accumulation.

1 Alpha 2 alpha 3 alpha collagen is arthritogenic

Native 1 alpha 2 alpha 3 alpha collagen (500 micrograms per rat) was both immunogenic and arthritogenic in Alderley Park rats (46% developed arthritis) but only immunogenic in Sprague-Dawley rats. Conversely, native type II collagen (500 micrograms per rat) was immunogenic and arthritogenic in both strains (64% arthritic in Alderley Park strain, 57% arthritic in Sprague-Dawley strain). The inflammatory polyarthritis induced by 1 alpha 2 alpha 3 alpha collagen was similar to that produced by native type II collagen in clinical appearance, time of onset, and histology. Antibodies raised to native bovine type II collagen cross-reacted with native 1 alpha 2 alpha 3 alpha collagen and vice versa. Thus the minor collagen component of cartilage, the 1 alpha 2 alpha 3 alpha collagen, as well as the major collagen component, type II collagen, are immunogenic and arthritogenic in the rat, with strain differences.

Patterns of neuroleptic use among the institutionalised elderly

A survey was conducted of neuroleptic use amongst the residents of Local Authority homes for the elderly, and elderly patients in geriatric, psychogeriatric and general hospital wards in one of the London boroughs. Some 13% of the residents and patients surveyed were found to have received neuroleptics in the 24 h preceding the survey. Marked variation between homes and between wards and hospitals was observed, although for the sample overall associations were observed between disturbed behaviour and mood and the likelihood of receiving neuroleptics. Issues regarding the use of neuroleptics in the non-psychotic elderly are discussed.

Sedative-hypnotic drug use and ageing

Behavioural disadvantages associated with the use of sedative-hypnotic drugs in the elderly are considered in relation to four aspects of drug usage reported in the epidemiological literature between 1960 and 1982, viz. (1) the prevalence of drug usage; (2) the type of drug, and the dose used; (3) the typical duration of usage; and (4) the typical frequency of usage. Demographic characteristics of elderly hypnotic users are also examined. The pattern and prevalence of usage over the past 20 yr show many consistent features. In particular, the prevalence of drug usage among the elderly has remained relatively high, especially within institutional settings. Sex differences in the prevalence of sleeping drug usage, frequently reported for elderly populations, appear to be related to bereavement, health status, and age. The advanced age of hypnotic drug users, however, does not appear to influence the choice of hypnotic drug prescribed. Moreover, drugs and dosages typically prescribed, and the duration and frequency of use typically reported, do not reflect a consistent approach to the problem of minimizing some of the adverse behavioural consequences associated with sedative-hypnotic drug use in the elderly.