Mortality after discharge from hospital following an episode of diabetic ketoacidosis

AIMS

The rate of inpatient mortality associated with diabetic ketoacidosis (DKA) has steadily decreased in recent decades. However, there remains a significantly increased outpatient death rate following an episode of survived DKA. We undertook this study to investigate the observed increase in mortality following an episode of DKA.

METHODS

We completed a retrospective cohort study to investigate rates and causes of death in people admitted to our hospital with DKA between 2013 and 2018. DKA was confirmed by pre-defined biochemical parameters and cause of death data was extracted from multiple sources. Follow-up was for two years after discharge for all participants with one-year mortality being the main time point for analysis.

RESULTS

We identified 818 admissions to hospital with DKA, affecting 284 people. Twenty people died as inpatients and a further 40 people died during the two-year follow-up. Of these 60 participants, cause of death was able to be determined for 41 (68%), with most deaths occurring due to infection or macrovascular disease. Risk factors for death within a year of hospital discharge included older age, vascular complications of diabetes, intellectual impairment and residential care living. Those who survived an episode of DKA had a one-year age-corrected mortality rate 13 times higher than the general population. This was more marked in the younger cohort with those aged 15-39 years being 49 times more likely to die in the year after surviving a DKA admission compared to their general population counterparts.

CONCLUSION

An episode of diabetic ketoacidosis is associated with a significant outpatient mortality risk with most deaths due to infectious or macrovascular causes. This study should prompt investigation of predictive scoring tools to identify those at increased mortality risk after DKA and encourage the development of targeted interventions to reduce mortality.

Levels of haemolysis have no effect on femoral vein post-mortem tryptase levels

Haemolysis is reported to be an artefact that may alter post-mortem tryptase levels. However, previous studies did not sample peripheral blood using newly standardised methods. Recent studies have shown that some previously recognised peri- and post-mortem confounders can be muted by careful sample collection with first clamping and then sampling the femoral vein. This prospective study investigated the relationship between the degree of haemolysis of the blood samples and femoral vein post-mortem tryptase levels when sampled using this recommended method. Seventy consecutive post-mortem tryptase levels in non-anaphylactic deaths were compared to the degree of haemolysis of these samples, and results showed no significant correlation between them. The mean post-mortem tryptase level was 9.5 μg/L. This study demonstrated that the effects of haemolysis on femoral vein post-mortem tryptase was negligible when the blood was sampled using the recommended sampling method. Future studies on post-mortem tryptase as well as other typically used blood markers in forensics are recommended to adopt this method of blood sampling in routine practice.

Classifying Microscopic Acute and Old Myocardial Infarction Using Convolutional Neural Networks

ABSTRACT

Convolutional neural network (CNN) has advanced in recent years and translated from research into medical practice, most notably in clinical radiology and histopathology. Research on CNNs in forensic/postmortem pathology is almost exclusive to postmortem computed tomography despite the wealth of research into CNNs in surgical/anatomical histopathology. This study was carried out to investigate whether CNNs are able to identify and age myocardial infarction (a common example of forensic/postmortem histopathology) from histology slides. As a proof of concept, this study compared 4 CNNs commonly used in surgical/anatomical histopathology to identify normal myocardium from myocardial infarction. A total of 150 images of the myocardium (50 images each for normal myocardium, acute myocardial infarction, and old myocardial infarction) were used to train and test each CNN. One of the CNNs used (InceptionResNet v2) was able to show a greater than 95% accuracy in classifying normal myocardium from acute and old myocardial infarction. The result of this study is promising and demonstrates that CNN technology has potential applications as a screening and computer-assisted diagnostics tool in forensic/postmortem histopathology.

The effects of drying the rinsed dissected heart on postmortem heart weight

Blood and blood clots should be removed from the heart chambers before being weighed. The actual method in removing blood and blood clots may vary and can include manual removal with subsequent rinsing the heart in water. It is unclear whether drying the rinsed heart affects the heart weight. The objective of this article was to investigate the effects drying the rinsed dissected heart (residual rinsing water) on postmortem heart weight. The prospective study compared 44 dissected heart weights after being rinsed and after being pat dried. An average 18-20 g of residual rinsing water (4% of heart weight) was present in the dissected heart. The amount of residual rinsing water correlates positively with heart weight. The effects of drying the rinsed dissected heart were considered clinically insignificant. Although being clinically insignificant, this study highlights the lack of standardized approach in weighing the heart and the potential implications in interpreting heart weights.

Differences Between Central and Peripheral Postmortem Tryptase Levels

ABSTRACT

Postmortem tryptase is a commonly used biochemical test to aid in the diagnosis of fatal anaphylaxis, which is currently recommended to be sampled from peripheral (femoral) veins because of a research showing comparatively elevated levels from central blood sources. Previous studies have used nonstandardized or nondocumented sampling methods; however, more recent research demonstrates that tryptase levels may vary depending on the sampling method. This study used the recommended sampling method of aspirating the femoral vein after clamping and compared in a pairwise comparison with aspiration of central venous and arterial blood sources (inferior vena cava and aorta) in 2 groups of 25 nonanaphylactic deaths. We found no statistically significant differences in postmortem tryptase between central and femoral vein blood; however, sporadic outliers in central blood (particularly aortic blood reaching levels above documented cutoffs for fatal anaphylaxis) were observed. Our findings provide evidence for the existing recommendations that femoral vein blood remains the preferred sample for postmortem tryptase over central blood.

Identifying gross post-mortem organ images using a pre-trained convolutional neural network

Identifying organs/tissue and pathology on radiological and microscopic images can be performed using convolutional neural networks (CNN). However, there are scant studies on applying CNN to post-mortem gross images of visceral organs. This proof-of-concept study used 537 gross post-mortem images of dissected brain, heart, lung, liver, spleen, and kidney, which were randomly divided into a training and teaching datasets for the pre-trained CNN Xception. The CNN was trained using the training dataset and subsequently tested on the testing dataset. The overall accuracies were >95% percent for both training and testing datasets and have an F1 score of >0.95 for all dissected organs. This study showed that small datasets of post-mortem images can be classified with a very high accuracy using a pre-trained CNN. This novel area has the potential for future application in data mining, education and teaching, case review, research, quality assurance, auditing purposes, and identifying pathology.

Identifying Fatal Head Injuries on Postmortem Computed Tomography Using Convolutional Neural Network/Deep Learning: A Feasibility Study

Postmortem computed tomography (PMCT) is a relatively recent advancement in forensic pathology practice that has been increasingly used as an ancillary investigation and screening tool. One area of clinical CT imaging that has garnered a lot of research interest recently is the area of "artificial intelligence" (AI), such as in screening and computer-assisted diagnostics. This feasibility study investigated the application of convolutional neural network, a form of deep learning AI, to PMCT head imaging in differentiating fatal head injury from controls. PMCT images of a transverse section of the head at the level of the frontal sinus from 25 cases of fatal head injury were combined with 25 nonhead-injury controls and divided into training and testing datasets. A convolutional neural network was constructed using Keras and was trained against the training data before being assessed against the testing dataset. The results of this study demonstrated an accuracy of between 70% and 92.5%, with difficulties in recognizing subarachnoid hemorrhage and in distinguishing congested vessels and prominent falx from head injury. These results are promising for potential applications as a screening tool or in computer-assisted diagnostics in the future.

Higher Heart Weight in New Zealand Māori and Pacific Islanders

Heart weight is dependent on sex, age, height, and weight. Although previous autopsy studies showed no differences in heart weight between different ethnic groups, none have examined the New Zealand population of Māori and Pacific Islanders (Polynesians). The presented study compared heart weights between 101 European and 85 Polynesian suicide hanging deaths from New Zealand. Univariate linear regression coefficients for age, male sex, height, body weight, body mass index, and Polynesian ethnicity were positive and significant (P < 0.05). Apart from body mass index, subsequent multivariate analysis showed that all regression coefficients remained positive and significant (P < 0.05). Polynesian ethnicity seemed to be an independent predictor for increased heart weight in the study population. Apart from possible genetic factors, the higher heart weight in Polynesians may have other underlying reasons. Caution is required when interpreting heart weight in cases of sudden natural deaths, especially in this population.

Long QT molecular autopsy in sudden unexplained death in the young (1-40 years old): Lessons learnt from an eight year experience in New Zealand

BACKGROUND

To review long QT syndrome molecular autopsy results in sudden unexplained death in young (SUDY) between 2006 and 2013 in New Zealand.

METHODS

Audit of the LQTS molecular autopsy results, cardiac investigations and family screening data from gene-positive families.

RESULTS

During the study period, 365 SUDY cases were referred for molecular autopsy. 128 cases (35%) underwent LQTS genetic testing. 31 likely pathogenic variants were identified in 27 cases (21%); SCN5A (14/31, 45%), KCNH2 (7/31, 22%), KCNQ1 (4/31, 13%), KCNE2 (3/31, 10%), KCNE1 (2/31, 7%), KCNJ2 (1/31, 3%). Thirteen variants (13/128, 10%) were ultimately classified as pathogenic. Most deaths (63%) occurred during sleep. Gene variant carriage was more likely with a positive medical history (mostly seizures, 63% vs 36%, p = 0.01), amongst females (36% vs 12%, p = 0.001) and whites more than Maori (31% vs 0, p = 0.0009). Children 1-12 years were more likely to be gene-positive (33% vs 14%, p = 0.02). Family screening identified 42 gene-positive relatives, 18 with definitive phenotypic expression of LQTS/Brugada. 76% of the variants were maternally inherited (p = 0.007). Further family investigations and research now support pathogenicity of the variant in 13/27 (48%) of gene-positive cases.

CONCLUSION

In New Zealand, variants in SCN5A and KCNH2, with maternal inheritance, predominate. A rare variant in LQTS genes is more likely in whites rather than Maori, females, children 1-12 years and those with a positive personal and family history of seizures, syncope or SUDY. Family screening supported the diagnosis in a third of the cases. The changing classification of variants creates a significant challenge.

Sink or Swim: The Advantages of Full Postmortem Examination in Cases of Drowning

Background

There is current debate whether full postmortems should be carried out on drowning victims.

Objective

To document the value of full postmortem examinations of drowning victims.

Methods

Retrospective data gathered from 42 postmortem reports of drowning cases over a two-year period.

Results

Forty-two drowning cases were included, 34 of which were adult internal examinations. Excluding fluid analysis, 38.2% of drowning cases were found to have diagnoses other than drowning thought to have contributed significantly to death. This figure rose to 50% when fluid analysis was included in the postmortem examination. Eighty-eight point two percent of adult internal examination cases found incidental diagnoses other than drowning at postmortem.

Conclusion

There is advantage to routinely conducting full postmortem examinations on suspected drowning cases, including the extraction of fluid samples.

Sub-cellular damage by copper in the cnidarian Zoanthus robustus

Sessile organisms may experience chronic exposure to copper that is released into the marine environment from antifoulants and stormwater runoff. We have identified the site of damage caused by copper to the symbiotic cnidarian, Zoanthus robustus (Anthozoa, Hexacorallia). External changes to the zoanthids were apparent when compared with controls. The normally flexible bodies contracted and became rigid. Histological examination of the zoanthid tissue revealed that copper had caused sub-cellular changes to proteins within the extracellular matrix (ECM) of the tubular body. Collagen in the ECM and the internal septa increased in thickness to five and seven times that of controls respectively. The epithelium, which stained for elastin, was also twice as thick and tough to cut, but exposure to copper did not change the total amount of desmosine which is found only in elastin. We conclude that copper stimulated collagen synthesis in the ECM and also caused cross-linking of existing proteins. However, there was no expulsion of the symbiotic algae (Symbiodinium sp.) and no effect on algal pigments or respiration (44, 66 and 110 microg Cu L(-1)). A decrease in net photosynthesis was observed only at the highest copper concentration (156 microg Cu L(-1)). These results show that cnidarians may be more susceptible to damage by copper than their symbiotic algae.

Chemotherapy-induced peripheral neuropathy as a predictor of neuropathic pain in breast cancer patients previously treated with paclitaxel

e20505

Background: Neuropathic pain (NP) remains difficult to control for a significant proportion of patients with cancer. Chemotherapy induced peripheral neuropathy (CIPN) is postulated as an initial stage to the development of NP. Among breast cancer patients, taxanes, platinum agents, and vinca alkaloids are most likely to cause NP. The purpose of this study was to assess the extent to which those who experienced CIPN (NCI toxicity criteria ≥ grade 2 sensory neuropathy) during paclitaxel chemotherapy were at risk of developing chronic NP, controlling for disease- and treatment-related variables (e.g., stage of disease, location of tumor chemotherapy and other cancer therapies, dose of chemotherapy and duration of treatment), clinical health status (e.g., comorbid conditions), and sociodemographic characteristics (e.g., age, race). Methods: We conducted a follow-up survey of breast cancer patients who previously participated in clinical trials for paclitaxel. Patients were asked if they have ever been diagnosed by the physician or healthcare provider for NP during the survey. Clinical trial data (NCI Toxicity, cummulative dose) were abstracted from a clinical database. Results: Of the 430 potential respondents, 240 responded to the survey. Mean follow-up time was 9.5 years (SD=2.1). Sixty three percent of the respondents had grade 2 or greater sensory neuropathy during their previous treatment with paclitaxel. Follow-up data showed that 18% (43/240) were subsequently diagnosed by their physician to have NP. Logistic regression analysis showed that those with CIPN during the trial were 3 times more likely to having been diagnosed with NP (OR=3; 95%CI=1.2; 7.2; p<0.001), which persisted in the multivariable model. Other variables found to be associated with NP included cummulative dose of paclitaxel, and comorbid conditions such as diabetes and osteoarthritis. Patients with NP reported twice as many visits to their health care provider (p=0.028); had taken more prescription (50% versus 19%; p=0.0001) for pain relative to those without NP. Conclusions: We provide empirical evidence on the importance CIPN as a risk factor for NP in breast cancer patients.Prospective studies with larger cohorts are needed to validate our findings.

No significant financial relationships to disclose.

Magnetoresistance of oblique angle deposited multilayered Co/Cu nanocolumns measured by a scanning tunnelling microscope

In this work we present the first magnetoresistance measurements on multilayered vertical Co(∼6 nm)/Cu(∼6 nm) and slanted Co(x nm)/Cu(x nm) (with x≈6, 11, and 16 nm) nanocolumns grown by oblique angle vapour deposition. The measurements are performed at room temperature on the as-deposited nanocolumn samples using a scanning tunnelling microscope to establish electronic contact with a small number of nanocolumns while an electromagnet generates a time varying (0.1 Hz) magnetic field in the plane of the substrate. The samples show a giant magnetoresistance (GMR) response ranging from 0.2 to 2%, with the higher GMR values observed for the thinner layers. For the slanted nanocolumns, we observed anisotropy in the GMR with respect to the relative orientation (parallel or perpendicular) between the incident vapour flux and the magnetic field applied in the substrate plane. We explain the anisotropy by noting that the column axis is the magnetic easy axis, so the magnetization reversal occurs more easily when the magnetic field is applied along the incident flux direction (i.e., nearly along the column axis) than when the field is applied perpendicular to the incident flux direction.

Preferred orientation in Ru nanocolumns induced by residual oxygen

Ru nanocolumns were grown on a native oxide covered Si(100) substrate using an oblique angle sputter deposition technique with substrate rotation at room temperature. Scanning tunneling microscopy images of conventional Ru film show the presence of straight columnar features on the film surface, which are very different from the nearly circular features observed on the nanocolumns surface. X-ray diffraction spectra confirm that these nanocolumns have (100) as the preferred orientation instead of the (002) orientation observed for a conventional film. The oxygen to Ru atomic ratio was determined for both the nanocolumns and the conventional film by using X-ray photoelectron spectroscopy. The nanocolumns were observed to incorporate about 6 times more oxygen than the conventional film near the surface region. We argue that the oxygen segregates onto the high-density (002) plane whereas it permeates through comparatively open planes like (100) and (101). The adsorbed oxygen atoms serve as a diffusion barrier for the landing Ru adatoms and inhibit the growth of the (002) plane. This results in the absence of the (002) plane and development of (100) and (101) planes in the nanocolumns. The oxygen plays a decisive role in determining the crystallographic orientation and the feature size/shape over the nanocolumns and conventional film surfaces.

A needs assessment for regionalization of trauma care in a rural state

Systems of trauma care in urban areas have a demonstrated survival benefit. Little is known of the benefit of trauma system organization in rural areas. We hypothesized that examination of all trauma deaths during a 1-year period would provide opportunities to improve care in our rural state. We used a medical examiner database of trauma deaths occurring during a 1-year period. Five board-certified surgeons analyzed deaths as preventable (P), potentially preventable (PP), and non-preventable (NP) using modified Delphi technique. There were 223 trauma deaths during a 1-year period. Most (63%) died at the scene prior to any medical intervention. Adjudication of the deaths demonstrated 5 P (2%; 95% CI 1-5%), 36 PP (16%; 95% CI 12-27%), and 179 NP (81%; 95% CI 76-86%). Agreement among trauma surgeons was only moderate with a k of 0.46. Suicide accounted for a significant number of the overall trauma deaths at 32 per cent. Rural trauma system design should focus on discovery, as that is where the majority of deaths occur. Suicide is a significant problem in this rural state that should be aggressively targeted with prevention programs.

A Needs Assessment for Regionalization of Trauma Care in a Rural State

Systems of trauma care in urban areas have a demonstrated survival benefit. Little is known of the benefit of trauma system organization in rural areas. We hypothesized that examination of all trauma deaths during a 1-year period would provide opportunities to improve care in our rural state. We used a medical examiner database of trauma deaths occurring during a 1-year period. Five board-certified surgeons analyzed deaths as preventable (P), potentially preventable (PP), and nonpreventable (NP) using modified Delphi technique. There were 223 trauma deaths during a 1-year period. Most (63%) died at the scene prior to any medical intervention. Adjudication of the deaths demonstrated 5 P (2%; 95% CI 1–5%), 36 PP (16%; 95% CI 12–27%), and 179 NP (81%; 95% CI 76–86%). Agreement among trauma surgeons was only moderate with a k of 0.46. Suicide accounted for a significant number of the overall trauma deaths at 32 per cent. Rural trauma system design should focus on discovery, as that is where the majority of deaths occur. Suicide is a significant problem in this rural state that should be aggressively targeted with prevention programs.

Amprenavir in combination with lamivudine and zidovudine versus lamivudine and zidovudine alone in HIV-1-infected antiretroviral-naive adults. Amprenavir PROAB3001 International Study Team

OBJECTIVES

To compare the antiviral activity and safety of a new protease inhibitor, amprenavir (141W94) in combination with lamivudine and zidovudine, versus lamivudine and zidovudine alone in HIV-1 infected, antiretroviral-naive subjects.

DESIGN

Subjects (n=232) with a CD4 T cell count of > or =200 cells/mm3, plasma HIV-1 RNA levels of > or =10000 copies/ml, and < or =4 weeks of prior nucleoside antiretroviral therapy, were stratified according to baseline plasma HIV-1 RNA level (10000-30000; 30000-100000; or >100000 copies/ml). Subjects received double-blind treatment with either 1200 mg amprenavir twice daily in combination with lamivudine (150 mg twice daily) and zidovudine (300 mg twice daily) (amprenavir/lamivudine/zidovudine) or matched placebo, lamivudine and zidovudine for 16 weeks. Thereafter, subjects with confirmed plasma HIV-1 RNA levels of > or =400 copies/ml could add open-label amprenavir or switch to other antiretrovirals and continue treatment for up to a minimum of 48 weeks. The primary endpoint of the study was defined as the proportion of subjects with plasma HIV-1 RNA of <400 copies/ml at 48 weeks.

RESULTS

At 48 weeks, a significantly greater proportion of amprenavir/lamivudine/zidovudine subjects had plasma HIV-1 RNA levels <400 copies/ml than lamivudine/ zidovudine subjects in the overall population: 41 versus 3% (intent-to-treat missing equals failure analysis) (P<0.001); 93 versus 42% (as-treated analysis) (P<0.001); and within each of the three randomization strata (P<0.001). Subjects on amprenavir/lamivudine/zidovudine experienced longer time to event (permanent discontinuation of randomized therapy or viral rebound) than those on lamivudine/zidovudine (median of 33 versus 13 weeks; P<0.001). A significantly greater incidence of drug-related nausea, vomiting, rash and oral/perioral paresthesia was observed with amprenavir/lamivudine/zidovudine than with lamivudine/zidovudine.

CONCLUSIONS

Amprenavir, in combination with lamivudine and zidovudine, has potent and durable antiviral activity in antiretroviral-naive subjects over 48 weeks. Amprenavir was safe and generally well tolerated.

Human hepatic cytochrome P450 2D6-like activity in nonhuman primates: catalytic characterization in vitro

Previous studies have identified the monkey as an animal model for the genetic polymorphism affecting human hepatic cytochrome P450 2D6 enzyme. However, contrary to an earlier in vivo observation, the present study failed to find evidence of polymorphism of this enzyme activity in liver preparations of 84 African green (Cercopithecus aethiops) monkeys. The kinetics of dextromethorphan O-demethylation were similar in liver microsomes from African green (n = 21) and Crab eater (Macaca fascicularis, n = 7) monkeys (Km = 1.1 +/- 0.07 and 1.7 +/- 0.27 microM; Vmax = 215 +/- 71.7 and 152 +/- 21.1 nmol/mg/h, respectively). These Km values were lower and less variable than those in liver microsomes from 10 human extensive metabolizers (5.3 +/- 2.43 microM). Furthermore, the Vmax of the reaction in human liver microsomes was significantly lower (32 +/- 15.7 nmol/mg/h; P < .001). Inhibitor constants (Ki values) determined in monkey and human liver microsomes were highly correlated (r = 0.97), but two high-affinity inhibitors of the human enzyme (quinidine and lobeline) were approximately 40-fold less potent in monkey livers than in human livers. These data show that the monkey enzyme is functionally homologous, but is not identical to human hepatic cytochrome P450 2D6. Failure to observe poor metabolizer monkeys does not preclude their potential usefulness in evaluating the role of human hepatic cytochrome P450 2D6 activity in drug addiction and neurotoxicity because of the possibility of producing poor metabolizer phenocopies by potent hepatic cytochrome P450 2D6-like enzyme inhibitors in monkeys.

Use of electroneuronography in monitoring facial nerve paralysis

FNP is a disease entity seen in a variety of clinical settings. We recommend early ENoG evaluation of every total facial nerve paralysis to assess the percentage of degeneration. ENoG is an objective, permanent record with prognostic significance especially in 16% of those patients who are predicted to have a poor outcome without further intervention. In consultation with the patient a treatment plan can thus be proposed to optimize the opportunity for recovery.

Toxicological implications of extended space flights

The dominant reason for exposing humans to the risks of space flight is their ability to perform complex tasks and make complex decisions. To fulfill such a role, crews must be shielded against even incipient degradation of performance capacity. The space environment contains potential hazards ranging from microgravity to infectious microorganisms to chemical toxicants. An extensive literature indicates that incipient disruptions of function may occur at low levels of exposure to toxic agents and degrade performance. Such questions need to be pursued before irreversible decisions are made about space vehicle design.

Lung clearance and retention of toner, utilizing a tracer technique, during chronic inhalation exposure in rats

Male and female F-344 rats were exposed to 6 hr/day, 5 days/week for up to 24 months to a special test toner at 0, 1, 4, and 16 mg/m3, TiO2 at 5 mg/m3, or SiO2 at 1 mg/m3 by the inhalation route. 59Fe-labeled iron oxide and 85Sr-labeled polystyrene particles were periodically inhaled by the nose-only route and used to measure alveolar clearance rates during the course of the study. This method was used to describe a maximum functionally tolerated dose (MFTD). Pulmonary retention of toner and control materials (TiO2 and SiO2) was measured after 3, 9, 15, 21, and 24 months of exposure. The quantity of all three materials retained in the lungs and lung-associated lymph nodes increased with exposure duration and level. The final pulmonary burdens of toner at the three exposure levels were 0.22, 1.73, and 15.6 mg/lung, respectively. Alveolar clearance of both tracers was substantially impaired at the toner high-exposure level, and moderately slowed at the toner middle-exposure level. The excessive quantity of toner retained and the substantially retarded clearance in the toner high-exposure group are indicative of "lung overloading." Alveolar clearance of 85Sr-polystyrene particles was slightly slowed in the TiO2-exposed group and substantially impaired in the SiO2-exposed group. The alveolar clearance of the unexposed rats decreased about 30% during the study, a change ascribed to aging. For a general description of the toxicokinetics of the various dusts, a semiempirical kinetic model was developed, which could generally be useful for the extrapolation of lung retention of insoluble particles from a subchronic to a chronic inhalation study. Both the maximum tolerated dose (MTD) and the MFTD were exceeded at the toner high-exposure level during the study in rats.

Pulmonary response to toner upon chronic inhalation exposure in rats

A chronic inhalation study of a test toner was conducted by exposure of groups of F-344 rats for 6 hr/day, 5 days/week for 24 months. The test toner was a special Xerox 9000 type xerographic toner, enriched in respirable-sized particles compared to commercial toner, such that it was about 35% respirable according to the ACGIH criteria. The target test aerosol exposure concentrations were 0, 1.0 (low), 4.0 (medium), and 16.0 (high) mg/m3. Titanium dioxide (5 mg/m3) and crystalline silicon dioxide (1 mg/m3), used as negative and positive controls for fibrogenicity, were also evaluated. Inhalation of the test toner or the control materials showed no signs of overt toxicity. Body weight, clinical chemistry values, food consumption, and organ weights were normal in the toner- and TiO2-exposed groups, except for a 40% increase in lung weight in the toner high-exposure group. All of the changes in the toner-exposed groups were restricted to the lungs or associated lymph nodes. A chronic inflammatory response was evident from the bronchoalveolar lavage parameters for the toner high-exposure group. The incidence of primary lung tumors was comparable among the three toner-exposed groups and the TiO2-exposed, and air-only controls, as well as consistent with historical background levels. A mild to moderate degree of lung fibrosis was observed in 92% of the rats in the toner high-exposure group, and a minimal to mild degree of fibrosis was noted in 22% of the animals in the toner middle-exposure group. The pulmonary changes in the toner high-exposure group were smaller in magnitude than those found in the crystalline silica-exposed group. The comparative fibrogenic potency of TiO2, toner, and SiO2 was estimated to be 1:5:418 using a dosimetric model and assuming a common mechanistic basis. There were no pulmonary changes of any type at the toner low-exposure level, which is most relevant in regard to potential human exposures. The lung alterations in the toner high-exposure group are interpreted in terms of "lung overloading," a generic response of the respiratory system to saturation of its detoxification capacity. The maximum tolerated dose (MTD) criterion was met at the toner high (16 mg/m3)-exposure level.

Reversibility of clearance impairment after subchronic test toner inhalation

In a chronic study of a test toner in F-344 rats an impairment of alveolar clearance and increased toner retention were observed at the high and, to a lesser degree, at the middle exposure level throughout the study. The objectives of the present study were: 1. To investigate the nature and the time course of test toner and surrogate tracer alveolar clearance and toner retention behaviour following a subchronic exposure interval. 2. To investigate the dependence of the response upon the pulmonary burden of the test toner.

Lung response to test toner upon 2-year inhalation exposure in rats

SPF F-344 rats were exposed 6 h/day 5 days/wk for up to 24 months to a special test toner at 0, 1, 4 and 16 mg/m3 or TiO2 at 5 mg/m3, or SiO2 at 1 mg/m3, by the inhalation route. The animals were kept for an additional 6 weeks in filtered air. Surviving animals were sacrificed at 25.5 months after start of exposure. Life-span and causes of death were independent of treatment and in accordance with published values. No evidence for systemic toxicity or any upper-respiratory system effects were found in the toner-exposed groups. The incidence of lung tumors was comparable in the control, 3 toner and TiO2-exposed groups. An incidence of 18%, combined benign and malignant tumors was observed in the quartz-treated rats. A slight to moderate degree of fibrosis was observed at the toner high exposure level in all animals, while a very slight degree of fibrosis was noted in 20% of the animals at the toner middle (4 mg/m3) exposure level. The fibrogenic potency of the test toner was calculated to be comparable to TiO2. No pulmonary changes were seen at the toner low (1 mg/m3) and environmentally most relevant exposure level.

Trauma, sport, and malignant cerebral edema

Sudden cerebral swelling and death secondary to craniocerebral trauma has been noted in children and young adults. This is due to an increase in intracerebral blood, either secondary to an increase in cerebral blood volume or a redistribution of intracranial blood from the pial to the intraparenchymal vessels. Sequential craniocerebral trauma has been associated with the syndrome of "malignant cerebral edema"; the possibility of a "compliance compromised brain" has been suggested as the cause. The additional possibility of asymptomatic encephalitis leading to a compliance compromised brain and malignant cerebral edema is discussed.

The influence of oral contraceptives on the postmolar human chorionic gonadotropin regression curve

This article reports a retrospective analysis of 149 evaluable cases of molar pregnancy managed at Women's Hospital, Los Angeles County/University of Southern California Medical Center, from January 1977, through June, 1983. In the 84 cases prior to 1981, the patients received estrogen-progestogen oral contraceptives after evacuation while the 55 patients seen after that used nonhormonal contraceptives. The frequency of abnormal regression of the serum beta-subunit of human chorionic gonadotropin in the two groups was not significantly different (22.6% in the hormonal contraception group versus 34.5% in the nonhormonal contraception group). The groups were compared for known and potential risk factors and were nearly identical with respect to patient age, parity, maternal blood type, and race. There were also no significant differences with respect to uterine size, preevacuation beta-subunit of human chorionic gonadotropin serum titer greater than 100,000 mIU/ml, and frequency of theca-lutein cysts. Gestational age was significantly shorter and the frequency of cases with a preevacuation beta-subunit of human chorionic gonadotropin serum titer greater than 250,000 mIU/ml significantly higher in the nonhormonal contraception group, indicating that the nonhormonal contraception group had a higher risk for abnormal human chorionic gonadotropin regression than the hormonal contraception group. We conclude that this study provides no evidence that the use of estrogen-progestogen oral contraceptives prior to human chorionic gonadotropin remission increases the risk for invasive mole or choriocarcinoma following molar pregnancy.

Inhalation and intravenous studies of UF6/UO2F2 in dogs

Nineteen UF6/UO2F2 inhalation studies were undertaken in purebred, female beagle dogs (N = 16) to examine inter alia, (a) the possible relations of exposure, whole body, lung and renal uranium levels to excretion rates; (b) the threshold U6+ dose and renal concentration for renal injury; (c) the distribution and retention functions for U6+ in major tissues; (d) biochemical indicators of renal injury; and (e) aspects of U-induced tolerance. Each of these issues was investigated in the context of the chemical toxicity of U6+ following brief exposures to 235UO2F2 in the presence or absence of HF (the decomposition products of 235UF6). Both gamma-(235U) and alpha-(234U) counting methods were applied. In nine studies on 5 dogs, UO2F2 was administered intravenously. The major findings from both types of studies include: (1) UO2F2 retention time in the lungs is shorter than for UO3 or uranyl nitrate, viz. greater than 80% translocated with T 1/2 of less than 20 min; (2) the urinary elimination of U6+ follows closely to the ICRP excretion equation; (c) an absorbed dose of approximately 10 micrograms U6+ kg-1 body weight appears to be effective in producing renal injury; (d) a renal concentration of 0.3 micrograms g-1 kidney is close to a threshold concentration for renal injury; and (e) urinary and blood biochemical changes and histopathologic data were acquired and evaluated in both novice and tolerant animals. This report, considers all of these objectives and findings: Those involving biochemical indices and uranium-induced tolerance will be more fully reported elsewhere. In general, the dog studies attest to the usefulness of the intravenous human studies for certain U6+ dose-response data and interface well with new retention data on intravenous uranyl citrate in dogs by Stevens et al.