Amygdala and Insula Connectivity Changes Following Psychotherapy for Posttraumatic Stress Disorder: A Randomized Clinical Trial

BACKGROUND

Exposure-based psychotherapy is a first-line treatment for posttraumatic stress disorder (PTSD), but its mechanisms are poorly understood. Functional brain connectivity is a promising metric for identifying treatment mechanisms and biosignatures of therapeutic response. To this end, we assessed amygdala and insula treatment-related connectivity changes and their relationship to PTSD symptom improvements.

METHODS

Individuals with a primary PTSD diagnosis (N = 66) participated in a randomized clinical trial of prolonged exposure therapy (n = 36) versus treatment waiting list (n = 30). Task-free functional magnetic resonance imaging was completed prior to randomization and 1 month following cessation of treatment/waiting list. Whole-brain blood oxygenation level-dependent responses were acquired. Intrinsic connectivity was assessed by subregion in the amygdala and insula, limbic structures key to the disorder pathophysiology. Dynamic causal modeling assessed evidence for effective connectivity changes in select nodes informed by intrinsic connectivity findings.

RESULTS

The amygdala and insula displayed widespread patterns of primarily subregion-uniform intrinsic connectivity change, including increased connectivity between the amygdala and insula; increased connectivity of both regions with the ventral prefrontal cortex and frontopolar and sensory cortices; and decreased connectivity of both regions with the left frontoparietal nodes of the executive control network. Larger decreases in amygdala-frontal connectivity and insula-parietal connectivity were associated with larger PTSD symptom reductions. Dynamic causal modeling evidence suggested that treatment decreased left frontal inhibition of the left amygdala, and larger decreases were associated with larger symptom reductions.

CONCLUSIONS

PTSD psychotherapy adaptively attenuates functional interactions between frontoparietal and limbic brain circuitry at rest, which may reflect a potential mechanism or biosignature of recovery.

PTSD Psychotherapy Outcome Predicted by Brain Activation During Emotional Reactivity and Regulation

OBJECTIVE

Exposure therapy is an effective treatment for posttraumatic stress disorder (PTSD), but many patients do not respond. Brain functions governing treatment outcome are not well characterized. The authors examined brain systems relevant to emotional reactivity and regulation, constructs that are thought to be central to PTSD and exposure therapy effects, to identify the functional traits of individuals most likely to benefit from treatment.

METHOD

Individuals with PTSD underwent functional MRI (fMRI) while completing three tasks assessing emotional reactivity and regulation. Participants were then randomly assigned to immediate prolonged exposure treatment (N=36) or a waiting list condition (N=30). A random subset of the prolonged exposure group (N=17) underwent single-pulse transcranial magnetic stimulation (TMS) concurrent with fMRI to examine whether predictive activation patterns reflect causal influence within circuits. Linear mixed-effects modeling in line with the intent-to-treat principle was used to examine how baseline brain function moderated the effect of treatment on PTSD symptoms.

RESULTS

At baseline, individuals with larger treatment-related symptom reductions (compared with the waiting list condition) demonstrated 1) greater dorsal prefrontal activation and 2) less left amygdala activation, both during emotion reactivity; 3) better inhibition of the left amygdala induced by single TMS pulses to the right dorsolateral prefrontal cortex; and 4) greater ventromedial prefrontal/ventral striatal activation during emotional conflict regulation. Reappraisal-related activation was not a significant moderator of the treatment effect.

CONCLUSIONS

Capacity to benefit from prolonged exposure in PTSD is gated by the degree to which prefrontal resources are spontaneously engaged when superficially processing threat and adaptively mitigating emotional interference, but not when deliberately reducing negative emotionality.

Selective Effects of Psychotherapy on Frontopolar Cortical Function in PTSD

OBJECTIVE

Exposure therapy is an effective treatment for posttraumatic stress disorder (PTSD), but a comprehensive, emotion-focused perspective on how psychotherapy affects brain function is lacking. The authors assessed changes in brain function after prolonged exposure therapy across three emotional reactivity and regulation paradigms.

METHOD

Individuals with PTSD underwent functional MRI (fMRI) at rest and while completing three tasks assessing emotional reactivity and regulation. Individuals were then randomly assigned to immediate prolonged exposure treatment (N=36) or a waiting list condition (N=30) and underwent a second scan approximately 4 weeks after the last treatment session or a comparable waiting period, respectively.

RESULTS

Treatment-specific changes were observed only during cognitive reappraisal of negative images. Psychotherapy increased lateral frontopolar cortex activity and connectivity with the ventromedial prefrontal cortex/ventral striatum. Greater increases in frontopolar activation were associated with improvement in hyperarousal symptoms and psychological well-being. The frontopolar cortex also displayed a greater variety of temporal resting-state signal pattern changes after treatment. Concurrent transcranial magnetic stimulation and fMRI in healthy participants demonstrated that the lateral frontopolar cortex exerts downstream influence on the ventromedial prefrontal cortex/ventral striatum.

CONCLUSIONS

Changes in frontopolar function during deliberate regulation of negative affect is one key mechanism of adaptive psychotherapeutic change in PTSD. Given that frontopolar connectivity with ventromedial regions during emotion regulation is enhanced by psychotherapy and that the frontopolar cortex exerts downstream influence on ventromedial regions in healthy individuals, these findings inform a novel conceptualization of how psychotherapy works, and they identify a promising target for stimulation-based therapeutics.

Structural chemistry of polycyclic heteroaromatic compounds. Part 13. Photoelectron spectra and electronic structures of tricyclic hetarenes of the anthracene type

The ultraviolet photoelectron spectra of two tricyclic heteroaromatic compounds (2,3) that are pi-isoelectronic with anthracene (1) have been recorded and analysed making use of semi-empirical AM1 and PM3, as well as density functional theory (DFT) B3LYP calculations. In compounds 2 and 3, one peripheral benzene ring of compound 1 is substituted by a thiophene ring that is either [b]- or [c]-annellated. In compounds 2 and 3, only small shifts are found for most of the ionization potentials of pi electrons. Since the ionization energies of all occupied pi molecular orbitals of compounds 1-3 could be assigned, a direct comparison of their pi electron energy is possible. Compared with compound 1, the pi-electron system of naphtho[2,3-b]thiophene (2) is stabilized by 0.6 eV, while that of naphtho[2,3-c]thiophene (3) is destabilized by 0.2 eV. [b]-Annellation of the thiophene ring is thus favourable while [c]-annellation is unfavourable.

Through the eye of the beholder: multiple perspectives on quality in women's health care

Quality is an illusive concept with different meanings to different people. Providers often define quality in terms of patient outcomes, professional standards of practice, predetermined criteria used to measure quality, and even subjective opinion. Patients describe quality in terms of the interpersonal aspects of care, how well they were treated, and the responsiveness of the provider to their needs. This qualitative study using a semi-structured interview defined quality from the perspectives of patients, physicians, nurses, and payers associated with a hospital-based women's service line, and how the attributes of quality varied among the multiple groups. The study also described how stakeholders become aware of quality and how they determined a hospital's quality. From the findings of the study, a conceptual framework of quality in women's health was developed.

Structural chemistry of polycyclic heteroaromatic compounds. Part XI. Photoelectron spectra and electronic structures of tetracyclic hetarenes of the triphenylene type

The UV photoelectron spectra of several tetracyclic heteroaromatic compounds (2-9) which are pi-isoelectronic with triphenylene (1) have been recorded and analysed making use of semiempirical AM1 and PM3 as well as ab initio/DFT B3LYP calculations. In one series of compounds (2-7), the peripheral benzene rings of 1 are successively substituted by thiophene rings that are either [b]- or [c]-annellated with the central benzene unit. In 2-7 only marginal shifts are found for most of the IPs of electrons. In the benzotrithiophenes 5-7, a systematic variation is displayed by IP(pi7). Compared to 1, the pi electron system of benzo[c]trithiophene (7) is approximately two times as much destabilized as in the isomers 5 and 6 with [b]annellated thiophene rings. The IP[n(S)] values of the thiophene derivatives 2-7 indicate that these orbitals are clearly destabilized relative to thiophene. The same holds for the n(O) orbital of the furane derivative 9 in comparison with that of furane. In 9, only the higher pi MOs (pi7-pi9) are destabilized whereas the lower levels (pi1-pi4) are stabilized, and those in between (pi5-pi6) remain essentially unshifted. In the pyrrole derivative 8, all pi MOs are substantially destabilized by about 0.5-1.6 eV relative to 1.

Case management as a tool for clinical integration

Case management has evolved to meet the challenges of contemporary health care. As an effective strategy to promote clinical integration within health care systems, case management brings together population and individual approaches to development and coordination of evidence-based, outcome-focused health, disease, and illness management programs and services. A three-level prevention-focused model for health care management across the continuum of care is presented.

A comparison of temperature measurements using three ear thermometers

Following anecdotal and research-based reports of inaccuracies encountered with the use of ear thermometers in patient care settings, this two-phase study was designed to compare the accuracy of three ear thermometers when used in a multioperator environment. The within-subject variation (limits of agreement) in ear temperature measurements obtained with the three ear thermometers in a multioperator condition by using an oral temperature reference standard ranged from +/- 1.25 degrees F to 1.85 degrees F. In multioperator, multisubject patient care environments using a pulmonary artery catheter core temperature as the reference standard, the limits of agreement for ear temperature measurements obtained with the three different ear thermometers ranged from +/- 2.19 degrees F to 2.85 degrees F. These results suggest that there is substantial variation in ear measurements and raise questions about the use of ear thermometers when there are multiple personnel taking temperatures, as occurs in hospital-based clinical practice environments. Handedness of the operator, position of the patient, and the ear used for measurement did not produce clinically significant variability in ear temperature measurements.

Automated, eight-cage indirect calorimetry in rats

We have constructed an automated, eight-cage indirect calorimeter (AIC) for the measurement of energy expenditure in rats. We compared the measurements of resting energy expenditure (REE) in rats during a 30-h fast obtained with the AIC with those obtained with a manual indirect calorimetry (MIC) system. There was both a high degree of correlation between the two techniques during the initial 18 h of the fast (r = 0.90, P < 0.05) and strong intertechnique agreement. REE (AIC) decreased during the final 12 h of the 30-h fast (79.6 +/- 2.7-72.0 +/- 4.4 kcal.kg-0.75.d-1 [mean +/- SD, P < 0.01]). REE (MIC) did not show a significant decrease during this part of the fast (79.7 +/- 2.6 - 75.2 +/- 4.7 kcal.kg-0.75.d-1 [P = NS]). During the final 12 h of the fast agreement between the two systems gradually dissipated and correlation was poor (r = 0.375, P < 0.05). The frequency of animal handling necessitated by MIC may have resulted in a stress-induced increase in metabolic work that would mask the animals' adaptive response to starvation. This investigation demonstrates the advantages of the AIC and calls into question the accuracy of manual methods under long-term starvation conditions.

Telephonic nursing: empowering patients at risk for preterm birth

Telephonic nursing is an innovative approach to providing prevention-focused care to patients at risk for preterm birth. Telephonic nursing includes case management and direct care services. A focus on health promotion supports client empowerment in self-care and decision making during the high-risk pregnancy.

A controlled trial of immunotherapy for asthma in allergic children

BACKGROUND

Injections of allergens are widely prescribed for patients with asthma, but little is known about the effectiveness of immunotherapy.

METHODS

We conducted a double-blind, placebo-controlled trial of multiple-allergen immunotherapy in 121 allergic children with moderate-to-severe, perennial asthma. The children, who required daily medication for their asthma, were randomly assigned to receive subcutaneous injections of either a mixture of up to seven aeroallergen extracts or a placebo. Maintenance injections were continued for 18 months or longer. Medications were adjusted every two to three weeks on the basis of peak flow rates and symptoms. The principal outcome was the daily medication score. Bronchial sensitivity to methacholine (the concentration provoking a 20 percent decrease in the forced expiratory volume in one second [PC20]) was measured twice yearly.

RESULTS

The median medication score declined from 5.4 to 4.9 in the immunotherapy group (P<0.001) and from 5.2 to 5.0 in the placebo group (P<0.001), but there was no significant difference between the groups (P>0.6). The number of days on which oral corticosteroids were used was similar in the two groups. Partial or complete remission of asthma occurred in 31 percent of the immunotherapy group and in 28 percent of the placebo group (P>0.5). There was no difference between the groups in the use of medical care, symptoms, or peak flow rates. The median PC20 increased significantly in both groups, but again with no difference between the two groups.

CONCLUSIONS

Immunotherapy with injections of allergens for over two years was of no discernible benefit in allergic children with perennial asthma who were receiving appropriate medical treatment.

Accuracy of electronic axillary temperature measurement in term and preterm neonates

The accuracy of axillary temperature measurement using an electronic thermometer in the predictive mode was investigated in term and preterm infants. Predictive mode measurements were compared to axillary monitoring mode measurements and to rectal temperature recordings. Fifty temperature recordings were obtained in each of four groups of neonates (full-term/radiant warmer, full-term/open crib, preterm/radiant warmer, preterm/incubator). Correlation of axillary predictive and monitoring mode temperatures ranged from r = 0.83 to 0.90. Correlations between axillary monitoring mode and rectal measurements were r = 0.69 to 0.80, and between predictive mode and rectal measurements were r = 0.59 to 0.80. Small, statistically significant differences were found between predictive and monitoring mode axillary temperatures in preterm neonates (0.1 to 0.2 degrees F). Rectal temperatures were higher than axillary predictive temperatures by 0.5 degrees F and higher than axillary monitoring mode temperatures by 0.7 degrees F. Ranges of variation of +/- 0.8 to 1.1 degrees F were similar in comparisons of rectal with axillary predictive and monitoring mode measurements. The results of this study support the use of axillary measurement in the predictive mode for clinical measurement of temperature in neonates. Clinicians should be aware of the expected differences between measurements at axillary and rectal sites and the potential for variation in measurements across measurement modes and sites.

Infrared tympanic thermometry for neonatal temperature assessment

OBJECTIVE

To investigate the accuracy and precision of infrared tympanic thermometer use with neonates by comparing with axillary and rectal measurements.

DESIGN

Descriptive, comparative study.

SETTING

Newborn nursery of a tertiary-level perinatal center.

SUBJECTS

Thirty-four full-term newborns.

INSTRUMENTS

Infrared thermometers were used to collect tympanic temperatures. An electronic thermometer was used to collect axillary and rectal temperatures.

RESULTS

There was no significant difference between tympanic and axillary temperatures. The range of variation (95% CI) was +/- 0.7-.9 degrees C. The mean difference between tympanic and rectal measurements was 0.4 degrees C. The range of variation was +/- 0.7-0.75 degrees C. Right ear measurements produced the best approximation of axillary temperature, and protected ear measurements produced the best approximation of rectal temperature. The protected ear was 0.2-0.3 degrees C higher than the exposed ear.

CONCLUSIONS

There was more variation between tympanic versus axillary and tympanic versus rectal measurements than between axillary and rectal measurements. Tympanic thermometry may be useful for rapid screening of neonatal temperature, but its usefulness for monitoring unstable neonates remains in question.

Using Roy's adaptation model in practice: nurses' perspectives

Using a qualitative research methodology, the utility of the Roy adaptation model as a framework for nursing practice within a hospital setting was investigated. The level of integration of the model into practice varied among nurses. The model was generally found to be useful in focusing, organizing, and directing nurses' thoughts and actions regarding patient care, resulting in a perception of improved quality of nursing process and patient outcomes. Prior education on the Roy model and participation in professional advancement activities facilitated model integration, while lack of education and resistance to change inhibited implementation of model-based practice.

Peak flow variation in childhood asthma: a three-year analysis

Measuring peak expiratory flow (PEF) variation has been suggested as a indicator of asthma disease severity and also of nonspecific bronchial hyperreactivity. To test these assumptions, we examined the relationships between PEF variation, methacholine reactivity, symptom scores, and medication requirements in 74 children with tightly controlled allergic asthma. The level of mean diurnal variation (MDV) for the group was 7.1%, which is generally regarded as normal. We found statistically significant correlations between MDV and both methacholine reactivity (r = 0.43, p = 0.0001) and symptom scores (r = 0.28, p = 0.016). These asthma variables were analyzed longitudinally in 33 children who were followed up at 6-month intervals for at least 36 months. Visit-to-visit changes in MDV were generally not reflective of changes in other variables. However, group levels of MDV gradually decreased over time, especially in children with initial MDV of more than 8%. This reduction in group MDV coincided with similar reductions in group medication requirements and methacholine reactivity. We conclude that children with moderately severe asthma that is tightly controlled may have normal levels of PEF variation. The correlation between PEF variation and other asthma variables is statistically significant but too weak to be useful in the treatment of individual patients. In contrast, measurement of MDV may be a useful indicator of disease severity in group studies of asthma.

Drug allergy

Although allergic drug reactions are just one type of adverse reaction to medications, they are clinically very important because of the morbidity and mortality they cause. An ever-expanding pharmacopeia increases the potential for allergic drug reactions. An understanding of the types of allergic drug reactions, their immunopathologic mechanisms, and the most likely medications involved; an approach to determine the drug responsible for the reaction; and ways to prevent future allergic drug reactions are important features in minimizing patient morbidity.

Allergy to protamine

Recent advances in medicine, such as cardiac catheterization, phoresis, dialysis, and cardiopulmonary bypass technology, have increased the need for heparin anticoagulation. To antagonize heparin's effect and prevent hemorrhagic complications after the procedure, protamine has likewise been used more frequently. With its increased use have come increased reports of adverse protamine reactions consisting of rash, urticaria, elevation of pulmonary artery pressure, systemic hypotension, and, at times, death. The elevation of pulmonary artery pressure, which appears to be a rather common occurrence in animals, may be an isolated finding without clinical consequences in humans. However, this pulmonary vasoconstriction may, when severe, lead to acute right-sided heart failure and systemic hypotension. Other protamine reactions involve a decrease in systemic vascular resistance and systemic hypotension without changes in pulmonary artery pressure. Causes of acute protamine reactions may involve the generation of anaphyatoxins and prostanoids either from protamine-heparin complexes or complement-fixing antiprotamine IgG antibodies, from inhibition of plasma Carboxypeptidase N, from crosslinking of cell-surface antiprotamine IgE on mast cells and basophils with subsequent mediator release, or from potentiation of IgE-mediated release of histamine through a polycationin-recognition site. Although we have come a long way in understanding the mechanisms by which protamine can cause its ill effects in humans, more work is clearly needed to define, in prospective studies, the incidence of and risk factors for protamine reactions in various patient groups, and to delineate more clearly which mechanisms are involved in each clinical type of acute protamine reaction. Hopefully, this will lead to strategies and protamine alternatives that will prevent or diminish, in frequency or severity, adverse protamine reactions. Alternatively, a clearer picture of the risk factors important for protamine reactions and the predictive value of diagnostic tests (e.g., protamine IgE antibody) can also minimize the clinical impact of this increasingly common adverse event.

Postpartum mothers' preferences for nighttime care of the neonate

This study, conducted in response to issues raised during implementation of a dyad care delivery system, investigated preferences of postpartum mothers for nighttime care of the neonate. For dyad as well as traditional care subjects, the availability of individual care options emerged as a theme in both personal preference and preference based on available hospital accommodation. Significant differences existed between dyad and traditional care subjects on second choices for nighttime care and on environmental variables.

Laboratory and hospital testing of new infrared tympanic thermometers

A patented approach to infrared thermometry based on the use of a standard pyrosensor has resulted in the development of two new infrared tympanic thermometers, one for professional use, the other for home use. Both were tested to evaluate accuracy in the laboratory and to evaluate equivalence to standards, correlation to standards, and precision in human subjects. Accuracy was found to be well within ASTM standards on both models. Mean ear temperatures were 0.2 degrees C below oral and 0.7 degrees C below bladder temperature. Correlations between ear and oral and ear and bladder temperatures were r = .77 to .84. Repeatability in the same ear was very high at r = .95 (left) and .97 (right). Reproducibility between left and right ear ranged from r = .89 to .92.

Serial immunological investigations in a patient who had a life-threatening reaction to intravenous protamine

Reactions to intravenous protamine include rash, urticaria, bronchospasm, hypotension, and/or pulmonary artery pressure elevation. We have previously shown that in diabetic patients receiving daily protamine-insulin injections, the presence of anti-protamine IgE or IgG antibodies are significant risk factors for acute, life-threatening reactions when protamine is given intravenously. To study protamine reactions further, we measured serum anti-protamine IgE and IgG antibody levels, in-vitro basophil histamine release and intracutaneous skin testing to protamine serially in an NPH-insulin dependent diabetic who had a severe, protracted anaphylactic reaction to protamine. At the time of his protamine reaction, his serum contained 8.5 ng/ml of anti-protamine IgE and 1.3 micrograms/ml of anti-protamine IgG antibody. One month following the reaction both anti-protamine IgE and IgG increased to 16 ng/ml (twofold rise) and 90.5 micrograms/ml (70-fold rise), respectively. With time, both anti-protamine IgE and IgG antibody declined. Serial intradermal skin tests using protamine sulphate did not discriminate between the protamine reactor and nine normal control subjects who had no prior exposure nor any demonstrable serum IgE antibody to protamine. In-vitro basophil histamine release to protamine sulphate was inconclusive in discriminating between the protamine reactor and normal control subjects. We postulate that protamine may be an incomplete or univalent antigen that must first combine with a tissue macromolecule or possibly heparin to become a complete multivalent antigen capable of eliciting IgE antibody-dependent mediator release.

Immunoreactivity of protamine preparations used to reverse heparin anticoagulation

To determine if four commercially available intravenous protamine preparations differed in their ability to bind to human antiprotamine antibody, the sera of seven protamine-insulin-dependent diabetics who had experienced life-threatening reactions to intravenous protamine and whose sera contained a mean of 67.4 micrograms/ml (range, 16-200 micrograms/ml) of antiprotamine IgG antibody were evaluated. Each serum was preincubated with buffer and 0.0014 to 1.4 mg/ml of the four protamine preparations before addition to an agarose-based solid-phase radioimmunoassay using 125I-radiolabeled staph protein A as the detection protein. In the seven sera, the concentration of soluble protamine inhibiting 50% of protamine antibody (IC50) was determined by interpolating from points above and below 50% inhibition for each protamine preparation. No significant difference was found in the IC50 among the four different protamine preparations (P greater than 0.25; Kruskal-Wallis). The authors concluded that there is no significant difference in the immunoreactivity of the four commercial protamine preparations with human antiprotamine IgG antibody. Thus, there appears to be no advantage in using a particular intravenous protamine preparation based on immunoreactivity with human antiprotamine antibody.

Rabbit F(ab')2 antihuman IgE is a universal skin test reagent in the evaluation of skin mast cell degranulation in vivo

Antihuman IgE is often used to study basophil- and mast cell-mediator release in vitro but is infrequently used in vivo. To evaluate in vivo skin reactivity to anti-IgE, an affinity-purified rabbit F(ab')2 fragment of antihuman IgE was injected intradermally in 22 nonallergic and 27 allergic subjects. All 49 subjects (including a subject with less than 1 ng/ml of total serum IgE) had positive immediate cutaneous reactions to anti-IgE. Although total serum IgE level was weakly correlated (r = -0.51; p less than 0.005) with in vivo skin reactivity to anti-IgE for the entire population, allergic subjects did not have significantly increased skin reactivity compared to nonallergic subjects (p = 0.18), despite having higher total serum IgE levels (p less than 0.002). A late-phase cutaneous response (LPR) to anti-IgE occurred in 60% of the allergic and in 50% of the nonallergic subjects. Subjects with an LPR required approximately tenfold higher concentrations of anti-IgE to produce an immediate wheal of 10 mm compared to subjects who did not develop an LPR (p = 0.02), suggesting that the concentration of the stimulus injected is more important for the development of a LPR than the size of the immediate cutaneous response. Skin reactivity to codeine phosphate (a non-IgE-dependent secretagogue) was correlated with skin reactivity to anti-IgE (r = 0.47; p less than 0.05), suggesting that in vivo skin mast cell degranulation is partially a function of mast cell releasability.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of protamine IgE and IgG antibodies with life-threatening reactions to intravenous protamine

Life-threatening reactions to intravenous protamine, administered to reverse heparin anticoagulation, have been reported with increasing frequency as a consequence of the escalating use of cardiac catheterization and coronary bypass surgery. Retrospective studies have shown that such reactions are more common in diabetic patients receiving daily subcutaneous injections of protamine-insulin preparations. To determine whether anti-protamine IgE or IgG antibodies might explain the increased risk for protamine reactions among patients with protamine-insulin-dependent diabetes, we conducted a case-control study of 27 patients (diabetic and nondiabetic) who had acute reactions to intravenous protamine and 43 diabetic patients who tolerated protamine without a reaction during diagnostic or surgical procedures. Cases and controls were grouped according to previous exposure to protamine-insulin preparations. In diabetic patients who had received protamine-insulin injections, the presence of serum antiprotamine IgE antibody was a significant risk factor for acute protamine reactions (relative risk, 95; P = 1.0 X 10(-5), as was antiprotamine IgG (relative risk, 38; P = 1.2 X 10(-5). No patients without previous exposure to protamine-insulin injections had serum protamine IgE antibodies. In this group, anti-protamine IgG antibody was a risk factor for protamine reactions (relative risk, 25; P = 0.0062). We conclude that in protamine-insulin-dependent diabetics, the increased risk of serious reactions when intravenous protamine was given appeared to be caused largely by antibody-mediated mechanisms. In nondiabetic subjects, the presence of protamine IgG was significantly associated with an increased risk of acute protamine reactions, although many nondiabetic subjects who had reactions had no IgG antibodies.

A protocol for performing reproducible methacholine inhalation tests in children with moderate to severe asthma

Reproducibility of methacholine inhalation tests (MIT) over a 2-wk period has been established in adult populations, but similar studies demonstrating reproducibility in children are lacking. We set out to establish the reproducibility of MIT in children as a prerequisite for a study of the natural history of airway hyperreactivity in asthmatic children. Most inhalation testing is done in persons with mild asthma because the recommended time interval for the withholding of medications prior to bronchial challenge is poorly tolerated by more labile asthmatics. In order to evaluate asthmatics with more severe disease, we modified a standardized method of methacholine inhalation to include a three-tier pretest medication regimen and investigated the reproducibility of this MIT protocol in 11 children as young as 6 yr of age. The three tiers were designed to keep baseline FEV1 greater than or equal to 70% predicted since diminished baseline airway caliber may affect MIT results. Eight of the 11 children were bronchodilator-dependent, and two of the eight also required inhaled steroids. Eleven children (6 to 13 yr of age) underwent MIT, between December and March, 1 day, 1 wk, and 1 month after an initial test. The PD20FEV1 using cumulative breath units (BU) were compared. The range of PD20FEV1 in the 11 children was 0.27 to 14.4 BU, with nine subjects classified as severe (PD20FEV1 less than 2.5 BU). We found a high degree of reproducibility of MIT. The interest correlation coefficient (r) was 0.98 after 1 day, 0.95 after 1 wk, and 0.96 after 1 month.(ABSTRACT TRUNCATED AT 250 WORDS)

Enamel dissolution by streptococcal fermentation of breakfast cereals

The amount of radioactive bovine enamel dissolved by the streptococcal fermentation products of 29 breakfast cereals was not dependent on their sugar content. Enamel dissolution was reduced by addition of a variety of inorganic and organic substances, of which those containing calcium were particularly effective.