Correction: Development of Therapeutic Alliance and Social Presence in a Digital Intervention for Pediatric Concussion: Qualitative Exploratory Study

[This corrects the article DOI: 10.2196/49133.].

Development of Therapeutic Alliance and Social Presence in a Digital Intervention for Pediatric Concussion: Qualitative Exploratory Study

BACKGROUND

Despite the promising benefits of self-guided digital interventions for adolescents recovering from concussion, attrition rates for such interventions are high. Evidence suggests that adults can develop therapeutic alliance with self-guided digital interventions, which is in turn associated with intervention engagement. However, no research has examined whether adolescents develop therapeutic alliance with self-guided digital interventions and what factors are important to its development. Additionally, social presence-the extent to which digital encounters feel like they are occurring in person-may be another relevant factor to understanding the nature of the connection between adolescents and a self-guided digital intervention, though this has yet to be explored.

OBJECTIVE

This qualitative study explored the extent to which adolescents recovering from concussion developed therapeutic alliance and social presence during their use of a self-guided digital mindfulness-based intervention. Additionally, this study aimed to determine factors important to adolescents' development of therapeutic alliance and social presence with the intervention.

METHODS

Adolescents aged between 12 and 17.99 years who sustained a concussion were recruited from 2 sites: a pediatric emergency department up to 48 hours after a concussion and a tertiary care clinic over 1 month following a concussion to capture adolescents who had both acute and persisting symptoms after concussion. Participants (N=10) completed a 4-week mindfulness-based intervention delivered through a smartphone app. Within the app, participants listened to audio recordings of mindfulness guides (voice actors) narrating psychoeducation and mindfulness practices. At 4 weeks, participants completed questionnaires and a semistructured interview exploring their experience of therapeutic alliance and social presence with the mindfulness guides in the intervention.

RESULTS

Themes identified within the qualitative results revealed that participants developed therapeutic alliance and social presence by "developing a genuine connection" with their mindfulness guides and "sensing real people." Particularly important to the development of therapeutic alliance and social presence were the mindfulness guides' "personal backgrounds and voices," such that participants felt more connected to the guides by knowing information about them and through the guides' calm tone of voice in audio recordings. Quantitative findings supported qualitative results; participants' average score for therapeutic alliance was far above the scale midpoint, while the mixed results for social presence measures aligned with qualitative findings that participants felt that the mindfulness guides seemed real but not quite as real as an in-person connection would.

CONCLUSIONS

Our data suggest that adolescents can develop therapeutic alliance and social presence when using digital interventions with no direct human contact. Adolescents' development of therapeutic alliance and social presence with self-guided digital interventions can be bolstered by increasing human-like qualities (eg, real voices) within interventions. Maximizing therapeutic alliance and social presence may be a promising way to reduce attrition in self-guided digital interventions while providing accessible treatment.

Longitudinal Brain Perfusion and Symptom Presentation Following Pediatric Concussion: A Pediatric Concussion Assessment of Rest and Exertion+MRI (PedCARE+MRI) Substudy

Emerging evidence suggests that advanced neuroimaging modalities such as arterial spin labelling (ASL) might have prognostic utility for pediatric concussion. This study aimed to: 1) examine group differences in global and regional brain perfusion in youth with concussion or orthopedic injury (OI) at 72 h and 4 weeks post-injury; 2) examine patterns of abnormal brain perfusion within both groups and their recovery; 3) investigate the association between perfusion and symptom burden within concussed and OI youths at both time-points; and 4) explore perfusion between symptomatic and asymptomatic concussed and OI youths. Youths ages 10.00-17.99 years presenting to the emergency department with an acute concussion or OI were enrolled. ASL-magnetic resonance imaging scans were conducted at 72 h and 4 weeks post-injury to measure brain perfusion, along with completion of the Health Behavior Inventory (HBI) to measure symptoms. Abnormal perfusion clusters were identified using voxel-based z-score analysis at each visit. First, mixed analyses of covariance (ANCOVAs) investigated the Group*Time interaction on global and regional perfusion. Post hoc region of interest (ROI) analyses were performed on significant regions. Second, within-group generalized estimating equations investigated the recovery of abnormal perfusion at an individual level. Third, multiple regressions at each time-point examined the association between HBI and regional perfusion, and between HBI and abnormal perfusion volumes within the concussion group. Fourth, whole-brain one-way ANCOVAs explored differences in regional and abnormal perfusion based on symptomatic status (symptomatic vs. asymptomatic) and OIs at each time-point. A total of 70 youths with a concussion [median age (interquartile range; IQR) = 12.70 (11.67-14.35), 47.1% female] and 29 with an OI [median age (IQR) = 12.05 (11.18-13.89), 41.4% female] were included. Although no Group effect was found in global perfusion, the concussion group showed greater adjusted perfusion within the anterior cingulate cortex/middle frontal gyrus (MFG) and right MFG compared with the OI group across time-points (ps ≤ 0.004). The concussion group showed lower perfusion within the right superior temporal gyrus at both time-points and bilateral occipital gyrus at 4 weeks, (ps ≤ 0.006). The number of hypoperfused clusters was increased at 72 h compared with 4 weeks in the concussion youths (p < 0.001), but not in the OIs. Moreover, Group moderated the HBI-perfusion association within the left precuneus and superior frontal gyrus at both time-points, (ps ≤ 0.001). No association was found between HBI and abnormal perfusion volume within the concussion group at any visits. At 4 weeks, the symptomatic sub-group (n = 10) showed lower adjusted perfusion within the right cerebellum and lingual gyrus, while the asymptomatic sub-group (n = 59) showed lower adjusted perfusion within the left calcarine, but greater perfusion within the left medial orbitofrontal cortex, right middle frontal gyrus, and bilateral caudate compared with OIs. Yet, no group differences were observed in the number of abnormal perfusion clusters or volumes at any visit. The present study suggests that symptoms may be associated with changes in regional perfusion, but not abnormal perfusion levels.

Acceptability, usability, and credibility of a mindfulness-based digital therapeutic for pediatric concussion: A mixed-method study

Background

The ability to cope with concussion symptoms and manage stress is an important determinant of risk for prolonged symptoms.

Objective

This open-label mixed-methods pilot study assessed the acceptability and credibility of a mindfulness-based intervention delivered through a digital therapeutic (DTx; therapeutic smartphone app) for pediatric concussion.

Methods

Participants aged 12 to 18 years were recruited from an emergency department within 48 hours of a concussion (acute cohort) or from a tertiary care clinic at least 1-month post-concussion (persisting symptoms cohort). Participants completed a novel 4-week mindfulness-based intervention, for 10 to 15 minutes/day, at a minimum of 4 days/week. At 2 weeks, participants completed a credibility and expectancy questionnaire. At 4 weeks, participants completed questionnaires assessing satisfaction, usability and working alliance, as well as a semi-structured phone interview.

Results

Ten participants completed the study outcomes (7 acute; 3 persisting symptoms). The intervention was perceived as credible (median/max possible = 6.50/9.00 [6.83,8.75]) and DTx was usable (median/max possible = 70.00/100.00 [55.00,82.50]). Participants rated their satisfaction with the DTx (median/max possible = 27.00/32.00 [24.50,29.50]) and the working alliance with the digital mindfulness guides (median/max possible = 3.92/5.00 [3.38-4.33]) as high. Four themes were identified from the qualitative data: (a) positive attributes; (b) negative attributes; (c) ideas for modifications; and (d) technical issues.

Conclusion

Results show modifications to the DTx, instructions and mindfulness intervention, and potential ways to increase adherence by leveraging positive attributes. A randomized control trial will assess the effectiveness of the DTx MBI to decrease the risk of persisting symptoms and reduce the symptom burden following pediatric concussion.

Associations between psychological resilience and metrics of white matter microstructure in pediatric concussion

This study investigated associations between psychological resilience and characteristics of white matter microstructure in pediatric concussion. This is a case control study and a planned substudy of a larger randomized controlled trial. Children with an acute concussion or orthopedic injury were recruited from the emergency department. Participants completed both the Connor-Davidson Resilience Scale 10 and an MRI at 72 h and 4-weeks post-injury. The association between resiliency and fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) at both timepoints were examined. We examined whether these associations were moderated by group. The association between resiliency captured at 72 h and diffusion tensor imaging metrics at 4 weeks was also investigated. Clusters were extracted using a significance threshold of threshold-free cluster enhancement corrected p < .05. A total of 66 children with concussion (median (IQR) age = 12.88 (IQR: 11.80-14.36); 47% female) and 29 children with orthopedic-injury (median (IQR) age = 12.49 (IQR: 11.18-14.01); 41% female) were included. A negative correlation was identified in the concussion group between 72 h resilience and 72 h FA. Meanwhile, positive correlations were identified in the concussion group with concussion between 72 h resilience and both 72 h MD and 72 h RD. These findings suggest that 72 h resilience is associated with white matter microstructure of the forceps minor, superior longitudinal fasciculus, and anterior thalamic radiation at 72 h post-concussion. Resilience seems to be associated with neural integrity only in the acute phase of concussion and thus may be considered when researching concussion recovery.

Recombinant NY‐ESO‐1 Cancer Antigen: Production and Purification under cGMP Conditions

The cancer-testis antigen, NY-ESO-1, has been engineered into a bacterial expression plasmid which incorporates a His6-tag. The plasmid was transfected into E. coli strain BL21 and Master and Working cell banks generated from this expression system. Three 15-litre fermentations were performed under cGMP (code of Good Manufacturing Practice) conditions and the crude NY-ESO-1 tagged protein isolated as solubilised inclusion bodies. A three-step cGMP chromatography process (immobilised metal affinity, anion exchange, and hydrophobic interaction) was utilised to purify the protein. The purified NY-ESO-1 is being used in early stage human cancer vaccine trials in Australia and the U.S.A.

The mutagenicity of urban particulate matter in an enzyme free system is associated with the generation of reactive oxygen species

Urban particulate matter (UPM) contributes to lung cancer incidence. UPM has been shown to be genotoxic to mammalian cells and to induce mutations in the Ames assay. Here, we have studied the induction of mutations generated by direct acting mutagenic components of UPM, using the supF forward mutation assay. Plasmid pSP189 was exposed to UPM in aqueous solution in the presence of sucrose buffer, to reduce strand breaks. The mutation frequency induced by 1 microg/microl UPM was 4.99 mutants per 10(4) colonies. This was reduced to 0.84 and 1.48 mutants per 10(4) colonies by addition of mannitol (1 mM) or EDTA (1 mM), respectively. A large percentage of mutant plasmids contained frameshift mutations (57%), and 31% of mutant plasmids contained multiple mutations. Of the base substitution mutations, 88% were at GC pairs, with twice as many transversions as transitions. The types of mutations induced, the reduction of mutagenicity by the inclusion of the free radical scavenger, mannitol, or the metal chelator, EDTA, and the sequence context of the induced mutations all support the conclusion that the majority of mutations were induced by reactive oxygen species generated by metal ions present in the UPM. Most mutation studies with UPM have focused on organic carcinogens present on UPM. Our results highlight the potential contribution of metal ions to the mutagenicity of UPM.

Genotoxicity of size-fractionated samples of urban particulate matter

Urban particulate matter (UPM) includes particles of size smaller than 10 microm (PM10), which may impact on human respiratory and cardiovascular health. It has been reported previously that PM10 can induce DNA damage. We have collected size-fractionated PM10 at the roadside and measured the induction of DNA damage by different-sized UPM using the alkaline Comet assay and the plasmid strand-break assay. We found that foil disks were more suitable for collecting UPM than quartz fiber filters, as the UPM could be easily extracted from the foil disks and accurately weighed. Using the Comet assay, all size fractions induced DNA damage in A549 lung epithelial cells, with the finer fractions (D50% = 0.65 microm and lower) inducing the most damage. In the plasmid strand-break assay, in which DNA damage is induced by free-radical species generated in solution, the most damage was also induced by the finer fractions, although the finest fraction (D50% < 0.43 microm) did not induce as much damage as D50% = 0.65 and 0.43 microm. When an organic extract of a standard UPM sample was compared to the whole particles and the washed particles in the Comet assay, it was found that around 75% of the damage induced by the whole UPM could be induced by the organic extract. These results show that finer particulates have the greatest ability to induce DNA damage in lung epithelial cells and naked DNA, and that both organic and inorganic components of the UPM contribute to its genotoxic effects.

A survey of physicians' education in caring for the dying: identified training needs

BACKGROUND

Physicians receive limited systematic training in caring for dying people. The majority of training focuses on technical skills.

METHODS

This study surveyed medical students, residents, fellows, and attending physicians to identify physician needs and current types of training in caring for the terminally ill. The study questionnaire was designed to determine whether and when physicians were trained in caring for dying people, the nature of such training, and possible areas to be included in future training. Also requested was a description of a personal experience involving caring for a terminally ill person.

RESULTS

One hundred twenty-three questionnaires were distributed and 90 were returned. Data indicate a lack of standardized training in dealing with terminally ill people and an expressed need for periodic, continuous training. The training needs to be mandatory, be ongoing, and use multiple formats, including the integration of theoretical information and clinical practice. Physicians in this study desired training in the following topic areas: 1) pain management; 2) death and dying; 3) the quality of life and death; 4) DNR status.

CONCLUSIONS

Physicians in this study indicated a need for more training in how to care for the terminally ill. A model for training should start in medical school and continue throughout one's career. Providing a framework for lifelong professional development that integrates theoretical information and clinical practice with a multidisciplinary approach to patient care should form the basis of a training model.

Splicing of the VASE exon of neural cell adhesion molecule (NCAM) in human small-cell lung carcinoma (SCLC)

Expression of the neural cell adhesion molecule (NCAM) on small-cell lung carcinoma (SCLC) cell lines and tumour tissue has been investigated. Cell lines were found to express highly sialylated NCAM. Neuraminidase treatment revealed the presence of the 140- and 120-kDa isoforms with differential expression of a 95-kDa protein. Similar data were obtained with SCLC tumour tissues. These results were corroborated by Northern blotting where mRNA of 6.7 and 5.5 kb coding for the 140- and 120-kDa isoforms, respectively, were identified. In a few tumours, a weaker band of 7.4-kb mRNA coding for the 180-kDa NCAM was also identified. This result could not be confirmed biochemically due to shortage of material. Finally, a 5-kb transcript was identified in all SCLC samples examined. The NCAM isoform coded by this mRNA remains unknown. Using the polymerase chain reaction (PCR), we have demonstrated the presence of the VASE mini-exon in some isoforms of SCLC NCAM. The VASE mini-exon sequence in human SCLC differs from the published murine sequence by only one base change. This substitution does not result in altered amino-acid sequence.

An enzyme immunoassay for isotyping mouse monoclonal antibodies

A rapid, simply performed and relatively inexpensive enzyme immunoassay for isotyping mouse monoclonal antibodies is described, based on the urease/urea system. Because of the high sensitivity (less than 0.1 microgram/ml of immunoglobulin can be detected in cell culture medium) no treatment of the hybridoma supernatant sample is required prior to assay, and the isotype of a mouse immunoglobulin can be determined in about thirty minutes.

Plantar approach for excision of bilateral soft tissue masses in a child

A painful soft tissue mass of the plantar aspect of both feet, in a 5-year-old child, is presented. Plantar incisions are ideal in specific cases as long as the surgeon adheres to certain principles, as outlined in this manuscript. A discussion of lipomas is also presented. Optimum exposure is the key to total eradication of soft tissue lesions and to proper maintenance of wound healing. Location of the lesion presented warranted use of the plantar approach. Minimal hypertrophy of the plantar scar was achieved, as well as few symptoms by the patient.

Chronic tenosynovitis of the tibialis posterior tendon and the use of tenography

Tenosynovitis of the tibialis posterior tendon and the use of the tenogram is presented. The tenogram is used as a diagnostic aid in determining the etiology as well as the course of treatment of a symptomatic tibialis posterior tendon. Various treatments for tenosynovitis have also been described.

Diabetic osteoarthropathy versus diabetic osteomyelitis

The differentiation between diabetic osteoarthropathy and osteomyelitis is a very difficult one to make, even in the presence of a pedal ulceration. However, considering present medical costs, the incorrect diagnosis of osteomyelitis can be a costly one, not only for the hospital, but also for the patient. In light of a normal white blood cell count, a benign 67Ga-citrate scan, and two noncontiguous areas of bone destruction, the diagnosis of diabetic osteoarthropathy can be made without the necessity of a bone biopsy.

An evaluation of the use of a pH indicator for the detection of beta-lactamase in enzyme immunoassay

The use of a mixed pH indicator containing bromocresol purple and bromothymol blue was evaluated for the detection of beta-lactamase activity in enzyme immunoassays (EIA) based on this enzyme. The EIA was found to correlate well with a bioassay for antibodies to tetanus toxoid in sheep sera. Results could be read spectrophotometrically at 450 nm or visually as a colour change from dark blue to yellow. The mixed pH indicator was found to have a number of desirable features including good stability, ease of preparation and a sharp colour change which makes the system suitable for visual determination of titration end points.

Improved high-performance liquid chromatographic separation of urinary paracetamol metabolites using radially compressed columns

Methods have been adapted for the high-performance liquid chromatographic (HPLC) analysis of urinary paracetamol metabolites on radial compression columns. Enhanced resolution and decreased analysis time were two major advances. Various modifications to existing methods were made to counter the effect of the different C18 surface. Thus in ion suppression HPLC the addition of triethylamine at pH 3.0 (phosphate buffer) was necessary to block residual hydroxyl sites, while in ion-pair HPLC a higher tetrabutyl-ammonium hydroxide concentration of 0.01 M at pH 5.0 was used to enhance selectivity. The methods were successfully applied to the study of the metabolism of paracetamol, its glutathione conjugate and 3-thiomethylparacetamol in Sprague-Dawley rats. 3-Thiomethyl-paracetamol sulphoxide and its glucuronide and sulphate conjugates were shown to be metabolites of both 3-thiomethylparacetamol and paracetamol. 3-Thiomethylparacetamol sulphate was unresolved from the sulphates of paracetamol and 3-methoxyparacetamol in ion-pair HPLC. This raises a previously unrecognised problem in which the peak normally attributed to paracetamol sulphate contains metabolites arising from an oxidative metabolic pathway. Elevated levels of 3-methoxyparacetamol conjugates were found in human overdose urine and to some extent in analgesic nephropathy.

A new rapid semi-quantitative enzyme immunoassay suitable for determining immunity to tetanus

A sensitive enzyme immunoassay for rapidly assessing a patient's state of immunity to tetanus is described. The test, which uses 50 microliter sample of blood, plasma or serum, is done in a capillary tube and, by comparison with two adjacent reference tubes containing standardised sera, places immunity to tetanus in one of three categories--low-negative (less than 0.01 IU/ml), intermediate (0.01-1.28 IU/ml) or high (greater than 1.28 IU/ml). In a study of 90 clinical specimens assayed both by toxin neutralisation bioassay and capillary enzyme immunoassay the enzyme immunoassay accurately assessed the state of immunity to tetanus of the patients concerned.

Changes in immunoregulatory lymphocyte populations in patients with histoplasmosis

Circulating T-lymphocyte subpopulations were enumerated in 65 patients with histoplasmosis and correlated with the different clinical manifestations of the disease. Acute pulmonary histoplasmosis, rheumatologic, disseminated, and chronic inflammatory manifestations of histoplasmosis were all associated with a significant elevation above normal of OKT8+ (suppressor-cytotoxic) lymphocytes and a significantly lower than normal OKT4+ (helper-inducer)-lymphocyte to OKT8+-lymphocyte ratio. In contrast, cavitary disease was associated with an increase in OKT4+ lymphocytes, a decrease in OKT8+ lymphocytes, and a higher than normal OKT4/OKT8 ratio. Clinical recovery was associated with normalization of these values. Functional activity determined by coculture techniques correlated closely with T-lymphocyte subset measurements. These distinct subset abnormalities may help monitor immunological aspects of disease activity.

A rapid semi quantitative capillary enzyme immunoassay for digoxin

A rapid and sensitive enzyme immunoassay (EIA) which does not require highly trained personnel or specialised instrumentation is described for the estimation of digoxin in serum, plasma or whole blood samples. The method is based on the ability of digoxin in a clinical sample to inhibit the binding of urease-conjugated sheep-antidigoxin immunoglobulin to a glass capillary tube coated internally with a human serum albumin-digoxin conjugate. The bound enzyme activity can then be measured using a substrate solution containing urea and a pH indicator, most suitably bromocresol purple. The enzymic hydrolysis of urea produces ammonia which causes a vivid yellow to purple colour change in the pH indicator. Plasma samples from 92 patients receiving digoxin were screened in parallel with reference plasma containing 1.3 or 3.8 nmol/l digoxin. The results were available within a total test time of 30 min, and showed excellent correlation with those obtained by radioimmunoassay.

Monoclonal hybridoma antibodies against human IgE and their use in a rapid and sensitive enzyme immunoassay for the semiquantitative assessment of total IgE levels in human blood

A simple semiquantitative enzyme immunoassay (EIA) for the rapid estimation of IgE levels in specimens of human blood, plasma or serum is described. The test requires little labour input and does not require highly trained personnel or instrumentation. By using two monoclonal antibodies of different anti-IgE specificities it is possible, with a single incubation of 20 min at ambient temperature, to detect elevated IgE levels (greater than or equal to 333 IU/ml) within a total test time of 25 min, and low levels of IgE (less than or equal to 10 IU/ml) within 35 min. For diagnosis of elevated/normal IgE levels only, a single incubation of 10 min. at ambient temperature may be used with a total test time of less than 20 min. The EIA system utilizes glass capillary tubes and urease-labelled antibodies, a system that has proven satisfactory in other applications.

Monoclonal antibodies to drugs--digoxin

A number of monoclonal antibodies to digoxin, two of which have been further characterized, were produced by somatic cell fusion. No cross reactivity with chemically related drugs was detected. Preliminary in vivo studies showed altered digoxin pharmacokinetics in antibody treated mice. These monoclonal antibodies could be used for a standardized radioimmunoassay and in the treatment of digoxin toxicity.

Amanita phalloides-type mushroom poisoning

In the fall of 1981 the San Francisco Bay Area Regional Poison Control Center received more than 100 calls regarding wild mushroom ingestion. Ten cases, including three fatalities, had all the features of Amanita phalloides poisoning. Encephalopathy, coma and renal insufficiency occurred in all three patients who died, but did not occur in those who survived. Two of the three patients who died arrived at the hospital late in the course of their illness, and severe gastroenteritis with accompanying dehydration probably contributed to their deaths. The poison control center promoted public awareness of the mushroom hazard through newspaper and television stories and by notifying local health departments. It also has devised a simple form to improve the quality of data collection and to assist in later verification of suspected A phalloides poisoning.

An investigation of the use of urease-antibody conjugates in enzyme immunoassays

The development of urease (E.C.3.5.1.5) as a label for enzyme immunoassay (EIA) procedures is described and the use of such conjugates illustrated with examples. Urease catalyzes the hydrolysis of urea to carbon dioxide and ammonia. The production of ammonia may be detected readily by a pH shift which we have found best indicated by the vivid colour change (yellow to purple) of bromocresol purple incorporated in the substrate solution. This enzyme-substrate system offers a number of important advantages. The substrate in aqueous solution is stable, titration end points are sharp and readily visible and the enzyme is not inhibited by sodium azide. Thus, test reagents may be prepared with this preservative and stored ready to use. Urease of high specific activity is commercially available and because it does not occur in mammalian tissues, it is suitable for use in EIA tests to detect cell-associated antigens and their antibodies. Finally, the enzyme reaction may be stopped by the addition of organomercurial preservatives, thus allowing storage of developed tests for later examination.

3-thiomethylparacetamol sulphate and glucuronide: metabolites of paracetamol and N-hydroxyparacetamol

1. Two new metabolites of paracetamol, 3-thiomethylparacetamol sulphate and glucuronide, have been isolated and identified. 2. The metabolites occurred in both rat and mouse urine after administration of either paracetamol of N-hydroxyparacetamol. The amount excreted increased proportionally with the dose.

N-hydroxyacetaminophen: a postulated toxic metabolite of acetaminophen

The decomposition of N-hydroxyacetaminophen has been shown to occur via an initial first-order dehydration step to N-acetyl-p-benzoquinone imine with a rate constant at pH 7.6 of 8.66 x 10(-3) min-1 and a half-life of 80 min. This is followed by a complex reaction between the quinone imine and the N-hydroxy compound to ultimately yield p-nitrosophenol and acetaminophen. The glucuronide and sulfate conjugates of N-hydroxyacetaminophen have been observed as urinary metabolites of N-hydroxyacetaminophen. No N-hydroxylated metabolites were found among the metabolites of acetaminophen. These results have been interpreted to show that N-hydroxyacetaminophen is not a metabolite of acetaminophen. It is proposed that the hepatotoxicity and nephrotoxicity of acetaminophen are mediated by a direct oxidation of acetaminophen to the toxic reactive intermediate N-acetyl-p-benzoquinone imine by the cytochrome P450 dependent mixed-function oxidase system.

Analysis of T lymphocyte subsets in cytomegalovirus mononucleosis

Lymphocyte proliferative responses to mitogens and herpes virus antigens are diminished during cytomegalovirus (CMV) mononucleosis. We analyzed peripheral blood T lymphocytes from patients in the acute and convalescent phases of CMV mononucleosis using monoclonal antibodies directed against the T helper and the T cytotoxic-suppressor cell subsets. Acute CMV infection is associated with a reversal in the normal ratio of helper to suppressor T lymphocytes with relative and absolute decreases in T helper cells and corresponding increases in T suppressor cells. These alterations in T lymphocyte subsets are accompanied by diminished lymphocyte responses to the mitogen concanavalin A (Con A). During convalescence, helper T lymphocytes increase, suppressor T lymphocytes decrease, and Con A responses return to normal.

Analysis of T lymphocyte subsets in cytomegalovirus mononucleosis

Lymphocyte proliferative responses to mitogens and herpes virus antigens are diminished during cytomegalovirus (CMV) mononucleosis. We analyzed peripheral blood T lymphocytes from patients in the acute and convalescent phases of CMV mononucleosis using monoclonal antibodies directed against the T helper and the T cytotoxic-suppressor cell subsets. Acute CMV infection is associated with a reversal in the normal ratio of helper to suppressor T lymphocytes with relative and absolute decreases in T helper cells and corresponding increases in T suppressor cells. These alterations in T lymphocyte subsets are accompanied by diminished lymphocyte responses to the mitogen concanavalin A (Con A). During convalescence, helper T lymphocytes increase, suppressor T lymphocytes decrease, and Con A responses return to normal.

The Synthesis and Reactions of N-Hydroxyparacetamol (N,4'-Dihydroxyacetanilide)

The synthesis of N-hydroxyparacetamol (N,4'-dihydroxyacetanilide) is reported where a copper complex of the hydroxamic acids as a protecting group is used. It has been shown to decompose between pH 7 and 12 to give products which are derived from N-acetyl-p-benzoquinone imine.3'-Substituted 4'-hydroxyacetanilides are formed when a nucieophile is present. The properties of N-hydroxyparacetamol are consistent with it being the toxic, reactive intermediate involved in the hepatoxicity of paracetamol.

Liver and kidney damage induced by N-hydroxyparacetamol

1. Liver and kidney glutathione are depleted in rats and mice following administration of N-hydroxyparacetamol. 2. Centrilobular hepatic necrosis and necrosis of renal proximal convoluted tubules were also found, the liver lesion predominantly in mice and the renal lesion predominantly in rats. Glutathione depletion was not responsible for this species difference. 3. These results indicate that N-hydroxyparacetamol is the metabolic precursor of the reactive toxic intermediate of paracetamol. They are also relevant to the pathogenesis of the renal damage associated with long term abuse of phenacetin containing compound analgesics.