The nature of antiidiotype molecules induced by antiallotype. Presence of both latent allotype and allotypic internal images

Previously (9), I found that immunization of rabbits with antibody directed against variable region heavy chain VH polypeptides of a1 allotype induced the production of antiidiotype (anti-Id) molecules that appeared to bear images of the original a1 allotype. I now show that these anti-Id molecules can be fractionated into two populations: one population (a2a3- anti-Id) that lacks the nominal VH a2 or a3 allotype of the rabbit from which it was derived, and another population (a2a3+ anti-Id) that expresses these allotypes. Both anti-Id populations display epitopes that resemble a1 since: (a) they were capable of inhibiting 125I-a1 Ig binding to rabbit anti-a1, goat anti-a1, and mouse anti-a1 mAb; and (b) immunization of normal a2a3 rabbits with either anti-Id fraction led to the formation of specific anti-a1 antibody. Reductive cleavage of the anti-Id molecules showed that the a1 determinants in the a2a3- population were fully displayed on isolated H chains, consistent with the presence of latent a1 Ig. On the other hand, as expected for internal images encoded by the antigen-combining site, the a2a3+ anti-Id population required intact H and L chains for maximal a1 expression. The a1-like images within the a2a3+ anti-Id population do not appear to be identical to nominal or latent a1, however, since a2a3- anti-Id was invariably a more efficient inhibitor of a 1 Ig-anti-a1 binding than a a2a3+ anti-Id. These results indicate that immunization with antiallotype can result in the simultaneous production of both latent allotypes and allotypic internal images.     

Partners in caring: a partnership for healing

This article describes one organization's effort to create a family-friendly environment that supports the choice of patients for involvement of a family member or loved one in their care. Changing a culture requires a process that can emotionally drive the caregivers to agree with the need to change and sustain the efforts over a long period. This project, Partners in Caring, describes the philosophy, the journey of changing a culture, and the results achieved over a 7-year period. The Partners in Caring philosophy is "a commitment between a patient, care partner and healthcare team to a relationship of hands-on support based on compassion, communication and choice empowering people to heal in a nurturing manner." This concept laid a foundation for the development of a new model of care, which is described. The implementation has resulted in an improved patient and staff satisfaction and a decrease in patient complaints.     

Migraine and Platelet Aggregation in Patients Treated With Low Dose Acetylsalicylic Acid

SYNOPSIS
To discriminate between the general analgesic effect of acetylsalicylic acid (a.s.a.) and a specific effect by inhibition of platelets we treated 27 migraine patients with low doses of acetylsalicylic acid. In a double-blind randomized cross-over study a small change in number of migraine attacks was found which however must be ascribed to a period effect. Severity of attacks as judged by the patients was similar in the placebo and drug periods. The frequency of attacks and the effect of a.s.a. were not significantly different in patients with platelets relatively sensitive to ADP and those with a slow response to ADP. No correlation was found between number of attacks and inhibition of the ADP aggregation obtained by administration of a.s.a. We concluded that low doses of a.s.a. are not useful to reduce the number or the severity of migraine attacks, and that no correlation exists between migraine attacks and a.s.a. effects on ADP-induced platelet aggregation. High doses of a.s.a. appear to be beneficial in migraine only by a general analgesic effect.     

Association of lipoprotein(a) concentration and apo(a) isoform size with restenosis after percutaneous transluminal coronary angioplasty

Lp(a) is a unique class of lipoprotein particles that exhibits a considerable size heterogeneity resulting from the size polymorphism of apo(a), its unique protein component. An elevated level of Lp(a) in plasma has been proposed to be a risk factor for premature development of coronary artery disease. To evaluate the relationship between Lp(a) concentration and apo(a) isoform size with restenosis after percutaneous transluminal coronary angioplasty, Lp(a) levels and apo(a) phenotypes were determined in 204 patients who underwent a successful coronary angioplasty procedure and stent implantation. The patients were followed with clinical examinations and exercise tests at 1, 3, and 6 months, and a control coronary angiography was performed after 6 months to evaluate restenosis. Lp(a) levels were determined with an ELISA that is insensitive to the size heterogeneity of Lp(a), and the apo(a) isoforms were determined by a high-resolution agarose gel electrophoresis method followed by immunoblotting with a specific monoclonal antibody. Of the 146 patients who underwent angiographic evaluation, 57 (39%) had restenosis, whereas 89 (61%) did not. Lp(a) levels and the distribution of the expressed apo(a) phenotypes were compared in these two groups of patients. Although the mean and median Lp(a) levels were higher in the restenosed group, the difference was not statistically significant. However, a significant difference in Lp(a) values was found in women (P=0.043), even though, because of the small number of women in the study (n=35), no sound conclusions can be reached on the predictive role of Lp(a) in restenosis. There also was no difference in the distribution of apo(a) phenotypes between the two groups. Because of their wide distribution, Lp(a) values and apo(a) isoforms do not seem to be a useful indicator of risk of restenosis after percutaneous transluminal coronary angioplasty in our study cohort.     

Fixation of the first component of complement (C'la) by human antibodies

The fixation of the first component of complement (C'1a) by human antibodies and human cells has been studied by the use of the C'1a fixation and transfer test (C'1a FT test) of Borsos and Rapp.Cold agglutinin antibodies appear to require no more than one antibody molecule to fix one molecule of C'1a.Most warm agglutinin antibodies are IgG in immunoglobulin type and require at least two molecules of antibody to fix a molecule of C'1a. Donath-Landsteiner antibody has the same requirements for C'1a fixation. A single example of a warm agglutinin antibody which appears to require one molecule of antibody for the fixation of C'1a was found.Antibodies of the Rh system do not fix significant amounts of C'1a in the absence of anti-antibody when antiserum of a single Rh specificity was used. However, when three antisera at different specificity are present, C'1a may be fixed. Under these conditions cells from a patient with paroxysmal nocturnal hemoglobinuria may be lysed when fresh serum is added to provide the other components of complement.The presence of IgG antibodies could be detected by the use of anti-IgG(Hu) antiserum and a one-to-one relationship between the concentration of antiserum in the reaction and the amount of C'1a fixed could be established.The effect of temperature, ionic strength, papainization of the red cells, and repeated washing of the red cell-antibody aggregates on the amount of C'1a fixed was investigated. Conditions of maximal C'1a fixation were established for each class of antibodies.Globulins present in normal isologous or autologous serum are absorbed in small amounts to normal red cells in a manner analogous to warm agglutinin antibody. Their presence is detectable by the C'1a fixation and transfer test only with antiglobulin antiserum.Within certain limits, the C'1a fixation and transfer test provides a quantitative measure of the reaction of human red cells and antibodies to antigens on their surface.     

Further characterization of the plasma lipoprotein(a) distribution

The plasma lipoprotein(a) [Lp(a)] distribution in caucasians is heavily skewed to the right, with evidence of bimodality. As there is a well-described inverse relationship between apolipoprotein(a) [apo(a)] size and Lp(a) concentration, it is likely that the presence of multiple apo(a) isoforms of differing frequency has a significant impact on the final distribution of Lp(a) concentrations. We have previously described an immunoblot method for examining the relationship between apolipoprotein(a) [apo(a)] size and lipoprotein(a) [Lp(a)] mass among samples heterozygous for apo(a) size, thus eliminating confounding by null or undetected apo(a) isoforms. In the present study, this method has been applied to examine the plasma Lp(a) distribution, independent of the effects of apo(a) isoform size and frequency. Seventy subjects heterozygous for apo(a) size were studied. To take into account the inverse relationship (P <0.001) between apo(a) isoform size and Lp(a) concentration, Lp(a) data associated with each apo(a) isoform were normalized as multiples of the median Lp(a) concentration for that isoform. These apo(a) isoform-independent Lp(a) data demonstrated a strikingly multimodal distribution, with five major peaks. The relative frequencies of Lp(a) peaks 1–5 were 17.1%, 15.0%, 35.7%, 23.6%, and 8.6%, and associated median Lp(a) concentrations were 1.0, 6.2,15.0, 21.8, and 39.6 mg/dL, respectively. Multivariate analysis demonstrated that apo(a) isoform size accounted for 23% and isoform-independent Lp(a) peaks for 59.5% of the variation in Lp(a) concentration. Further investigation of the characteristics of the apo(a) isoform-independent Lp(a) distribution is warranted.     

The inverse association of plasma lipoprotein(a) concentrations with apolipoprotein(a) isoform size is not due to differences in Lp(a) catabolism but to differences in production rate.

Lipoprotein(a) (Lp[a]) is an atherogenic lipoprotein which is similar in structure to low density lipoproteins (LDL) but contains an additional protein called apolipoprotein(a) (apo[a]). Apo(a) is highly polymorphic in size, and there is a strong inverse association between the size of the apo(a) isoform and the plasma concentration of Lp(a). We directly compared the in vivo catabolism of Lp(a) particles containing different size apo(a) isoforms to establish whether there is an effect of apo(a) isoform size on the catabolic rate of Lp(a). In the first series of studies, four normal subjects were injected with radio-labeled S1-Lp(a) and S2-Lp(a) and another four subjects were injected with radiolabeled S2-Lp(a) and S4-Lp(a). No significant differences in fractional catabolic rate were found between Lp(a) particles containing different apo(a) isoforms. To confirm that apo(a) isoform size does not influence the rate of Lp(a) catabolism, three subjects heterozygous for apo(a) were selected for preparative isolation of both Lp(a) particles. The first was a B/S3-apo(a) subject, the second a S4/S6-apo(a) subject, and the third an F/S3-apo(a) subject. From each subject, both Lp(a) particles were preparatively isolated, radiolabeled, and injected into donor subjects and normal volunteers. In all cases, the catabolic rates of the two forms of Lp(a) were not significantly different. In contrast, the allele-specific apo(a) production rates were more than twice as great for the smaller apo(a) isoforms than for the larger apo(a) isoforms. In a total of 17 studies directly comparing Lp(a) particles of different apo(a) isoform size, the mean fractional catabolic rate of the Lp(a) with smaller size apo(a) was 0.329 +/- 0.090 day-1 and of the Lp(a) with the larger size apo(a) 0.306 +/- 0.079 day-1, not significantly different. In summary, the inverse association of plasma Lp(a) concentrations with apo(a) isoform size is not due to differences in the catabolic rates of Lp(a) but rather to differences in Lp(a) production rates.     

SEAT-BELT SYNDROME REVISITED

This report describes a complex syndrome of injuries occurring in a young female who was a back seat passenger wearing a lap-belt restraint in a high-speed road traffic accident. As a consequence of the forced flexion distraction injury of her lumbar spine, she sustained a fracture-subluxation of the first lumbar vertebra in association with a jejunal perforation and extensive small intestinal mesenteric laceration. She also had a large traumatic hernia of the anterior abdominal wall, which was overlooked at primary laparotomy. This report highlights collectively the classical combination of injuries associated with the lap-belt syndrome and demonstrates the importance of carefully inspecting the anterior abdominal wall for deficiencies, because traumatic herniation may be easily overlooked.     

Turnover of Lipoprotein (a) in Man

An elevated concentration of lipoprotein (a) [Lp(a)] in the serum has been considered a risk factor for coronary heart disease by various investigators. In the present study, the turnover of Lp(a) was investigated in nine individuals with serum Lp(a) levels ranging from 1 to 68 mg/100 ml. After intravenous injection of radioiodinated Lp(a), the radioactivity time-curve of the serum and the specific activitity time-curves of the isolated Lp(a) and Lp(a) apolipoproteins were measured for 14 d. More than 97% of the label was found in the protein moiety of Lp(a). During the entire study period, the serum radioactivity remained with Lp(a), only insignificant amounts of radioactivity were detectable in other lipoprotein fractions. The serum radioactivity time-curves and the specific activity time-curves of the isolated Lp(a) and Lp(a) apolipoproteins were identical.     

Determination of free apolipoprotein(a) in serum by immunoassay and its significance for risk assessment in patients with coronary artery disease.

This paper describes a new enzyme-linked ligand sorbent assay (ELLSA) to quantify free apolipoprotein(a) (apo(a)). The new test immobilizes free apo(a) utilizing a specific peptide that carries the amino acid sequence of a non-covalent apo(a) binding site on apoB3375-3405 (ligand-peptide). The ligand-peptide coupled to Sepharose was used in affinity chromatography to separate free apo(a) from whole serum. Isolated free apo(a) consisted of full length apo(a) and smaller apo(a). Additionally, free apo(a) levels determined by ELLSA as well as by electroimmunodiffusion correlated moderately well. Significantly increased serum concentrations of free apo(a) were found in coronary artery disease. The mean value of free apo(a) was three times higher in patients than in controls while the lipoprotein(a) (Lpla)) concentration was doubled. Utilizing receiver operating characteristic diagrams, it was shown that the free apo(a)-ELLSA had a better diagnostic test performance in atherosclerotic risk assessment than the Lp(a)-test: specificity free apo(a)-ELLSA 0.77, Lp(a)-test 0.81 [with (a:a)-enzyme immunoassay (EIA)] to 0.83 [with (a:B)-EIA]; sensitivity free apo(a)-ELLSA 0.57, Lp(a)-test 0.36 to 0.40. In conclusion, the new free apo(a)-ELLSA allows for the specific quantification of free apo(a). This provides an interesting indicator for atherosclerotic risk assessment.     

Kringle-containing fragments of apolipoprotein(a) circulate in human plasma and are excreted into the urine.

Apolipoprotein(a) [apo(a)] contains multiple kringle 4 repeats and circulates as part of lipoprotein(a) [Lp(a)]. Apo(a) is synthesized by the liver but its clearance mechanism is unknown. Previously, we showed that kringle 4-containing fragments of apo(a) are present in human urine. To probe their origin, human plasma was examined and a series of apo(a) immunoreactive peptides larger in size than urinary fragments was identified. The concentration of apo(a) fragments in plasma was directly related to the plasma level of Lp(a) and the 24-h urinary excretion of apo(a). Individuals with low (< 2 mg/dl) plasma levels of Lp(a) had proportionally more apo(a) circulating as fragments in their plasma. Similar apo(a) fragments were identified in baboon plasma but not in conditioned media from primary cultures of baboon hepatocytes, suggesting that the apo(a) fragments are generated from circulating apo(a) or Lp(a). When apo(a) fragments purified from human plasma were injected intravenously into mice, a species that does not produce apo(a), apo(a) fragments similar to those found in human urine were readily detected in mouse urine. Thus, we propose that apo(a) fragments in human plasma are derived from circulating apo(a)/Lp(a) and are the source of urinary apo(a).     

Confirmation and certainty in toxicology screening

Confirmation of presumptive positive urine drug screens, necessary to minimize the reporting of false-positive results, can be costly and time-consuming. The predictive value model can be used to select the confirming tests and to calculate the confidence of the result. The predictive value of a test result is the probability, based on the sensitivity and specificity of the test, that the result is a true positive or a true negative. The predictive value model applied to toxicology screening tests for drugs of abuse showed that prevalence, in addition to sensitivity and specificity, was the factor controlling the confidence level of a result. For example, the predictive value of a positive result for a screening test that has a sensitivity of 99% and a specificity of 99%, applied to screening in a population with a prevalence of 1% is 0.50; for a prevalence of 10%, it is 0.92. Confirmation with a second, chemically independent, test of equal sensitivity and specificity increases the predictive value to 0.99.     

The unique lipoprotein(a): properties and immunochemical measurement

Lipoprotein (a) [Lp(a)] represents a class of lipoprotein particles defined by the presence of apolipoprotein(a), a unique glycoprotein linked by a disulfide bond to apolipoprotein B-100 to form a single macromolecule. Apolipoprotein(a) is formed by three different structural domains having high amino acid sequence homology with plasminogen. One of the domains, called kringle 4, is present in multiple copies, the number of which varies and is genetically determined. This accounts for the size heterogeneity of apolipoprotein(a) and thus of Lp(a). Because high concentrations of Lp(a) are associated with atherosclerotic cardiovascular and cerebrovascular disease and may inhibit fibrinolysis, interest in measuring Lp(a) has increased considerably, leading to a rapid development of commercially available immunoassays for the measurement of Lp(a) in human plasma. However, the immunochemical measurement of Lp(a) has several peculiar problems in addition to those encountered by the measurements of other apolipoproteins. The major problems that need to be carefully evaluated are (a) the structural complexity and heterogeneity of Lp(a), (b) the homology of apolipoprotein(a) with plasminogen, (c) the lack of standardization of the methods, and (d) the lack of a common means of expressing the Lp(a) values.     

Constrained manifold learning for the characterization of pathological deviations from normality

This paper describes a technique to (1) learn the representation of a pathological motion pattern from a given population, and (2) compare individuals to this population. Our hypothesis is that this pattern can be modeled as a deviation from normal motion by means of non-linear embedding techniques. Each subject is represented by a 2D map of local motion abnormalities, obtained from a statistical atlas of myocardial motion built from a healthy population. The algorithm estimates a manifold from a set of patients with varying degrees of the same disease, and compares individuals to the training population using a mapping to the manifold and a distance to normality along the manifold. The approach extends recent manifold learning techniques by constraining the manifold to pass by a physiologically meaningful origin representing a normal motion pattern. Interpolation techniques using locally adjustable kernel improve the accuracy of the method. The technique is applied in the context of cardiac resynchronization therapy (CRT), focusing on a specific motion pattern of intra-ventricular dyssynchrony called septal flash (SF). We estimate the manifold from 50 CRT candidates with SF and test it on 37 CRT candidates and 21 healthy volunteers. Experiments highlight the relevance of non-linear techniques to model a pathological pattern from the training set and compare new individuals to this pattern.     

Facilitating speech in the patient with a tracheostomy

A tracheostomy tube decreases the ability of the patient to communicate effectively. The ability to speak provides an important improvement in the quality of life for a patient with a tracheostomy. In mechanically ventilated patients, speech can be provided by the use of a talking tracheostomy tube, using a cuff-down technique with a speaking valve, and using a cuff-down technique without a speaking valve. Speech can be facilitated in patients with a tracheostomy tube who are breathing spontaneously by use of a talking tracheostomy tube, by using a cuff-down technique with finger occlusion of the proximal tracheostomy tube, and with the use of a cuff-down technique with a speaking valve. Teamwork between the patient and the patient care team (respiratory therapist, speech-language pathologist, nurse, and physician) can result in effective restoration of speech in many patients with a long-term tracheostomy.     

In vitro inhibition of fibrinolysis by apolipoprotein(a) and lipoprotein(a) is size- and concentration-dependent.

Lipoprotein(a) (Lp(a)) is considered an independent risk factor for atherosclerotic heart and circulatory diseases. The unique, polymorphic character of Lp(a) is based on its apolipoprotein(a) (apo(a)), which has remarkable structural analogies with plasminogen, an important protein for fibrinolysis. The formation of plasmin from plasminogen is a fundamental step in the dissolution of fibrin. Repression of this step may lead to a deceleration of fibrinolysis. It has been suggested that Lp(a) has antifibrinolytic properties through apo(a) and that the apo(a)-size polymorphism has a distinct influence on the prothrombotic properties of Lp(a). However, the results on this topic are controversial. Therefore we used a standardized in vitro fibrinolysis model to provide further information on the influence of Lp(a) on plasmin formation. Monitoring the time-course of plasmin formation, we investigated the inhibition of plasmin formation through dependence on Lp(a), respectively, free apo(a) concentration. Furthermore, we investigated the influence of three Lp(a)/apo(a) phenotypes ((22K)Lp(a), 22 kringle-4 repeats; (30K)Lp(a), 30 kringle-4 repeats; (35K)Lp(a), 35 kringle-4 repeats). Adding varying amounts of Lp(a) to our model, we observed that the rate of plasmin formation was inversely related to the Lp(a) concentration. At 0.1 micromol/l (30K)Lp(a), for example, the plasmin formation was reduced by 12.7% and decreased further by 40.7% at 0.25 micromol/l Lp(a). A similar but more distinct effect was observed when free (30K)apo(a) was added to the model (25.3% at 0.1 micromol/l vs. 59.3% at 0.25 micromol/l). Comparing the antifibrinolytic influence of different apo(a) phenotypes we found that the reduction of plasmin generation advanced with the size of apo(a). At 0.1 micromol/l Lp(a) the reduction of the plasmin formation increased in the order (22K)Lp(a), (30K)Lp(a) and (35K)Lp(a) from 3.7% to 10.7% and 22.3%, respectively. Experiments with different phenotypes of free apo(a) showed similar results (0.5 micromol/l: (22K)apo(a), 56.4% vs. (30K)Lp(a), 80.4%). Summarizing these results, our study indicates a distinct interrelation of Lp(a)/apo(a) phenotype and concentration with the formation of plasmin. From the antifibrinolytic Lp(a)/apo(a) effect in vitro it may be hypothesized that Lp(a)/apo(a) also has an inhibitory influence on in vivo fibrinolysis.     

Rudimentary uterus in testicular feminization (author's transl)]

The absence of uterus has been regarded by a number of authors as a condition for the diagnosis of testicular feminization, although cases with a rudimentary uterus have been reported. However, their number within the framework of this syndrome cannot be exactly determined. In the present report on a 22 year-old patient with testicular feminization and uterus bicornis solidus a double uterus malformation identical with that described in the Mayer-Rokitansky-küster syndrome was found. Forms of testicular feminization with rudimentary uterus in genetically-male individuals may be explained by the absence of androgens, or the absence of reactivity on the part of the target organ, and a simultaneous disturbance (lessening) of the function of the so-called X-factor (oviduct repressor) during early embryonal development. Our own observations, as well as reports in the literature, suggest a theory according to which testicular feminization may be regarded as a series of morphological variants, from male-oriented forms with vaginal aplasie, hypertrophy of the clitoris and male distribution of pubic hair, to female-orientated ones with a vagina of normal length and a rudimentary uterus. The absence of a uterus as a condition for the definition of the syndrome can be maintained only so far as no cases have, as yet been observed with a normally-developed uterus in a typical position. The karyogram showed a small Y-chromosome. Functional anomalies may only be surmised, since Y-anomalies are frequent (3% in a random collection). The morphology of the testes mirrored the functional embryonal insufficiency (pre-pubertal, undifferentiated testicular tissue with a varying amount of stroma and Leydig cells); the basal excretion of testosterone, 17-ketosteroid fractions and pregnane in the 24-hour urine was within the normal range for males. Oestrogen production over and above the "adrenal values" was also present. The values for plasma testosterone, which are in accordance with those of males of a similar age, are considered as indicating the importance of "androgen resistance in the periphery" as a factor in the aetiology of testicular feminization.     

Modification of apolipoprotein(a) lysine binding site reduces atherosclerosis in transgenic mice.

Lipoprotein(a) contributes to the development of atherosclerosis through the binding of its plasminogen-like apolipoprotein(a) component to fibrin and other plasminogen substrates. Apolipoprotein(a) contains a major lysine binding site in one of its kringle domains. Destruction of this site by mutagenesis greatly reduces the binding of apolipoprotein(a) to lysine and fibrin. Transgenic mice expressing this mutant form of apolipoprotein(a) as well as mice expressing wild-type apolipoprotein(a) have been created in an inbred mouse strain. The wild-type apolipoprotein(a) transgenic mice have a fivefold increase in the development of lipid lesions, as well as a large increase in the focal deposition of apolipoprotein(a) in the aorta, compared with the lysine binding site mutant strain and to nontransgenic littermates. The results demonstrate the key role of this lysine binding site in the pathogenic activity of apolipoprotein(a) in a murine model system.