Delayed splenic hemorrhage: Myth or mystery? A Western Trauma Association multicenter study

BACKGROUND

Multi-detector computed tomography imaging is now the reference standard for identifying solid organ injuries, with a high sensitivity and specificity. However, delayed splenic hemorrhage (DSH), defined as no identified injury to the spleen on the index scan but delayed bleeding from a splenic injury, has been reported. We hypothesized that the occurrence of DSH would be minimized by utilization of modern imaging techniques.

METHODS

Data was retrospectively collected from 2006 to 2016 in 12 adult Level I and II trauma centers. All patients had an initial CT scan demonstrating no splenic injury but subsequently were diagnosed with splenic bleeding. Demographic, injury characteristics, imaging parameters and results, interventions and outcomes were collected.

RESULTS

Of 6867 patients with splenic injuries, 32 cases (0.4%) of blunt splenic hemorrage were identified. Patients were primarily male, had blunt trauma, severely injured (ISS 32 (9-57) and with associated injuries. Injuries of all grades were identified up to 16 days following admission. Overall, half of patients required splenectomy. All index images were obtained using multi-detector CT (16-320 slice). Secondary review of imaging by two trauma radiologists judged 72% (n = 23) of scans as suboptimal. This was due to poor scan quality primary from artifact(23), single phase contrast imaging (16), and/or poor contrast bolus timing or volume (6). Notably, only 28% of scans in patients with DSH were performed with optimal scanning techniques.

CONCLUSION

This is the largest reported series of DSH in the era of modern imaging. Although the incidence of DSH is low, it still occurs despite the use of multi-detector imaging and when present, is associated with a high rate of splenectomy. Most cases of DSH can be attributed to missed diagnosis from suboptimal index imaging and ultimately be avoided.

Cell-shaped silicon-on-insulator microdosimeters: characterization and response to 239PuBe irradiations

This work tested the feasibility of a silicon-on-insulator microdosimeter, which mimics the size and shape of specific cells within the human body, to determine dose equivalent from neutron irradiation. The microdosimeters were analyzed in terms of their basic diode characteristics, i.e., leakage current as a function of bias voltage. Lineal energy spectra were acquired using two different converter layers placed atop the microdosimeter: a tissue-substitute converter made from high-density polyethylene, and a boron converter consisting of epoxy coated with boron powder. The spectra were then converted into absorbed dose and dose equivalent. Experimental results were compared to Monte Carlo simulations of the neutron irradiations, revealing good agreement. Uncertainty in the dose equivalent determinations was 7.5% when using the cell-shaped microdosimeter with the tissue-substitute converter and 13.1% when using the boron converter. This work confirmed that the SOI approach to cell-mimicking microdosimetry is feasible.

Air leak during CPAP titration as a risk factor for central apnea

OBJECTIVES

Emergence of central sleep apnea has been described in the setting of continuous positive airway pressure (CPAP) initiation. The underlying mechanism is unclear; however, we postulate that air leak washing out anatomical dead space is a contributing factor.

DESIGN

Data were obtained from 310 patients with obstructive sleep apnea (OSA) who underwent either split-night or full-night CPAP titration during January to July of 2009. The majority (n = 245) underwent titration with a nasal mask. Average total leak and maximum total leak were measured at therapeutic CPAP level. Unintentional leak was calculated by subtracting manufacturer-defined intentional leak from maximum leak.

RESULTS

SUBJECTS WERE DIVIDED INTO TWO GROUPS: central apnea index (CAI) during titration < 5/hour and ≥ 5/hour. The groups were similar in terms of gender, age, BMI, and AHI. The CAI < 5 group had a median average leak of 45.5 L/min (IQR 20.8 L/min) versus 51.0 L/min (IQR 21.0 L/min) with CAI ≥ 5 (p = 0.056). Maximum leak was 59.5 L/min (IQR 27.0 L/min) with CAI < 5 and 75.0 L/min (IQR 27.8 L/min) with CAI ≥ 5 (p = 0.003). In the subset of subjects titrated using a nasal mask, median average leak was 42.0 L/min (IQR 17.0) in the CAI < 5 group and 50.0 L/min (IQR 16.8) in the CAI ≥ 5 group (p = 0.001). In the CAI < 5 group, median maximum leak was 57.0 L/min (IQR 23.0) versus 74.5 L/min (IQR 24.3) in the CAI ≥ 5 group (p < 0.001).

CONCLUSIONS

Leak during CPAP titration is associated with the development of acute central apnea; these data may have mechanistic and therapeutic implications for complex apnea.

COMMENTARY

A commentary on this article appears in this issue on page 1193.

An automated sleep-analysis system operated through a standard hospital monitor

STUDY OBJECTIVES

Sleep disordered breathing (SDB), a cause of clinically important cardiovascular comorbidity, is often not recognized and diagnosed. An automated system that detects SDB using signals from a standard hospital monitor might provide useful information about the presence and severity of SDB without the need to evaluate the patient in a sleep laboratory and without additional hardware. The aim of this study was to examine the feasibility and accuracy of routine overnight sleep testing for SDB detection by an automated analysis system that operates by analyzing signals derived from standard hospital monitors.

METHODS

Comparison of SDB detection by simultaneous "gold-standard" polysomnography and by Morpheus Hx (WideMed, Ltd., Herzliya, Israel), a bedside computerized analysis system (CAS) connected to a standard hospital monitor (ECG, respiratory impedance, end-tidal carbon dioxide (ETCO2), and SpO2). A total of 53 subjects were examined, 36 men and 17 women, all with suspected SDB. Each subject underwent an overnight sleep study, scored both by polysomnography and by CAS. The study was conducted in Brigham and Women's Hospital, Newton Center, MA.

RESULTS

CAS-derived values for apnea-hypopnea index and total sleep time, were each found to be highly correlated with the corresponding polysomnography results, with linear regression values of r = 0.96 and r = 0.82, respectively. Mean apnea-hypopnea index values were also quite similar (CAS of 15.5 +/- 20.0 vs polysomnography of 15.4 +/- 24.0).

CONCLUSIONS

An automated sleep-analysis system utilizing signals derived from a standard hospital monitor can be considered as a feasible and accurate method to detect and quantify SDB.

Assessment of a wrist-worn device in the detection of obstructive sleep apnea

OBJECTIVE

To assess the accuracy of a wrist-worn device (Watch_PAT100) to diagnose obstructive sleep apnea (OSA).

METHODS

Thirty adult subjects with and without suspected OSA simultaneously had a standard in-laboratory polysomnogram (PSG) and wore the Watch_PAT100 during a full-night recording. PSG sleep and respiratory events were scored according to standard criteria. Watch_PAT data were analyzed with an automated computerized algorithm which calculated the frequency of respiratory events per hour of actigraphy measured sleep using a combination of peripheral arterial tonometry (PAT) signal attenuation, desaturation on pulse oximetry, and changes in heart rate. This yielded a PAT apnea hypopnea index (AHI).

RESULTS

Mean age was 47.0+/-14.8 years, mean body mass index 31.0+/-7.6 kg/m(2), mean PSG AHI 23+/-23.9 events per hour, and mean PAT AHI 23+/-15.9 events per hour. There was a significant correlation between PAT AHI and AHI by PSG (r=0.87, P<0.001). To assess sensitivity and specificity of Watch_PAT, we constructed receiver operator characteristic curves using a variety of AHI threshold values (10, 15, 20, and 30 events per hour). Optimal combinations of sensitivity and specificity for the various thresholds were 82.6/71.4, 93.3/73.3, 90.9/84.2, and 83.3/91.7, respectively.

CONCLUSIONS

The Watch_PAT is a device that can detect OSA with reasonable accuracy. Thus, the Watch_PAT may be a useful method to diagnose OSA.

A minimalist approach to gene mapping: locating the gene for acheiropodia, by homozygosity analysis

Acheiropodia is an autosomal recessive disease that results in hemimelia (lack of formation of the distal extremities). We performed a complete genome screen of seven members of an extended pedigree that included three siblings with acheiropodia. Homozygosity mapping was used to identify regions most likely to harbor the gene for acheiropodia in this pedigree. In these two key regions (14p and 7q), further genotyping of one additional affected member of this pedigree plus seven additional unaffected siblings provided evidence, through linkage analysis, that the 7q36 region contains the acheiropodia gene. In this region, a maximum two-point LOD score of 3.81 (4.2 with multipoint analysis) was achieved, and a homozygous haplotype spanning a region of 11.7 cM was seen in all affected in this pedigree. Finally, genotypic analysis of two additional cases of acheiropodia with no known relation to the other samples revealed homozygous sharing of a portion of the same haplotype on 7q36, which reduces the chromosomal location of the acheiropodia gene to an 8.6-cM region. Localization of this gene, at the screening level, by use of data from only three affected subjects, provides an example of how certain genes may be mapped by use of a minimal number of affected cases.

Multiple centrosomal microtubule organising centres and increased microtubule stability are early features of VP-16-induced apoptosis in CCRF-CEM cells

Microtubular reorganisation contributing to apoptotic morphology occurs in normal and neoplastic cells undergoing apoptosis induced by cytotoxic drugs [1-3]. The aim of this study was to correlate the changes in the microtubules (MTs) with behavior of the centrosome in apoptotic cells, and to see whether post-translational changes in tubulin occurred with the emergence of apoptotic MT bands. Apoptosis was induced in the human T-cell leukaemia line (CCRF-CEM) by treatment with 17 microM etoposide over a 4 h period. The time course of changes was assessed using flow cytometry (FCM) and immunocytochemistry in cells labelled for a centrosomal antigen (CSP-alpha) or alpha-tubulins. One hour following treatment we observed multiple centrosomal microtubule organising centres (MTOCs) associated with the nucleus and the transient appearance of a subset of stable MTs detected with an antibody specific for acetylated alpha-tubulin, as the bands of MTs which lobulate the nucleus are formed. The altered properties of the MTs thus reflect changes in function as apoptosis progresses.

Cytogenetic abnormalities in benign lymphoid hyperplasia: a dual-parameter study using chromosome analysis and flow cytometry

This is a prospective study of lymphoid tissue showing benign reactive hyperplasia (18 lymph nodes and 2 tonsils), using cytogenetic analysis of cells stimulated with T- or B-cell mitogens. The reason for this study was the detection of an abnormal chromosomal population in cells from an enlarged lymph node excised from a 7-year-old female who on further investigation was found to be clinically well and after one year's close follow-up had not developed any further signs or symptoms of malignancy. In addition, DNA content was measured by flow cytometry (FCM) on fresh cell suspensions in 17 cases and fixed cell suspensions in 3 cases. Structural and numerical clonal chromosome abnormalities were found in 9 of the 20 samples, but no common specific defect was identified. FCM showed an abnormal DNA content in 10 of the 20 samples studied; 3 of these showed clonal chromosome abnormalities. Surface membrane immunoglobulin studies were carried out on 15 of the 20 samples using cell suspensions and frozen tissue sections. In 5 of the 15 cases, monoclonal surface immunoglobulin was detected. There was no direct correlation between the surface membrane immunoglobulin studies and the chromosome and FCM analyses. We conclude that aneuploidy is a common feature in reactive lymphoid tissue, but both cytogenetics and FCM are needed to identify it.

Improved visualization of the internal mammary artery with a new retractor system

A new sternal retractor system was developed to improve exposure of the internal mammary artery and protect the lung. This retractor can be used for either single or bilateral dissection of the internal mammary artery. It has been used in more than 2,000 cases with excellent results.

A pathologic study of allergic bronchopulmonary aspergillosis

A lung biopsy specimen was obtained from a 10-year-old boy with cystic fibrosis and allergic bronchopulmonary aspergillosis. Light microscopy revealed a marked inflammatory process that was largely bronchocentric. Infiltrating cells included lymphocytes, plasma cells, monocytes, and numerous eosinophils. Elastin layers were intact in blood vessels and markedly disrupted in bronchioles. By immunofluorescent, major basic protein was demonstrated in eosinophils, was freely deposited outside of eosinophils, especially in the interlobular septum, and was taken up by macrophages. A number of lymphocytes stained positively for IgE. Through an immunoperoxidase stain, septate hyphae of Aspergillus were clearly observed in the lung parenchyma. A significant increase in interleukin-2 positive-staining T cells was observed with an approximate 2:1 ratio of helper to suppressor cells. The use of newer immunohistologic techniques has enabled us to gain additional insights into the pathogenesis of allergic bronchopulmonary aspergillosis.

A simple and rapid immunological technique for visualising chromosome-mediated gene transfer (CMGT)

A method is described for visualising chromosome-mediated gene transfer (CMGT) by detecting chromosomes labelled with bromodeoxyuridine (BrdU) using a monoclonal antibody to BrdU. In this experiment, the CCRF-CEM T cell line was grown in the presence of BrdU and the labelled chromosomes were isolated and transfected into human embryonic fibroblasts. Uptake and retention of chromosomes were compared for transfection with either PEG or DMSO treatments. Following transfection the labelled chromosomes could be visualised in recipient cells using a monoclonal antibody to BrdU, followed by immunoperoxidase staining. Chromosome uptake into cells was similar for both DMSO and PEG treatments and was a relatively frequent event; about 1 in 5 recipient cells had labelled material present. This technique can be used to assess the technical aspects of the earliest stages of chromosome-mediated gene transfer.

Flow cytometric and karyotypic analysis of a primary small cell carcinoma of the prostate: a xenografted cell line

A human small cell undifferentiated carcinoma of the prostate, xenografted in nude mice, was analyzed both cytogenetically and by DNA flow cytometry. The DNA content of the line indicated its stability on serial passage, and was consistent with the cytogenetic findings. The banded karyotype was hypodiploid with nonrandom losses of chromosomes #6, #7, #10, and #13. Structural rearrangements involved chromosomes #1 and #2, and there were three unidentified markers. The findings were compared with those described in other types of prostatic carcinoma.

The 14q+ marker in hairy cell leukaemia. A cytogenetic study of 15 cases

Leukaemic cells from 19 patients with hairy cell leukaemia (HCL), characterised by morphological, immunological and ultrastructural criteria, were investigated for chromosome abnormalities after stimulation with B-cell mitogens (Pokeweed mitogen (PWM), lipopolysaccharide B and EBV). The cells from all cases had a B-cell phenotype and in each case only a single light chain type was expressed on the membrane of the cells. Only 15 patients with adequate metaphases are included in this study. Clonal chromosome abnormalities were observed in 12 patients of which five had a 14q + involving q32. Of the remaining 3 cases 1 had nonclonal abnormalities and 2 had normal karyotypes. The donor chromosomes were identified in 3 cases and were found to be 9, 18 and 22. An interstitial rearrangement of chromosome 14 involving band q22 was seen in 2 cases and a deletion of chromosome 14 at q24 in 1 case. Amongst other chromosome abnormalities 12p was involved in 4 cases, 12q in 2 cases and chromosomes 7 and 22 in 3 cases each. The significance of the abnormalities has been discussed in relation to sites of cellular oncogenes. Our study demonstrates that chromosome abnormalities common to other B-cell disorders are present in HCL.

Prognostic significance of chromosome abnormalities in chronic lymphocytic leukaemia

Lymphocytes from 33 out of 63 patients with B-cell chronic lymphocytic leukaemia (B-CLL) were successfully stimulated for cytogenetic analysis by means of two B-cell mitogens: pokeweed mitogen and lipopolysaccharide-B, used after pretreatment of the cells with neuraminidase and galactose oxidase. All patients had abnormal clones in 30-100% of the cells analysed. Chromosomes more frequently involved were Nos. 1, 3, 6, 11, 12, 13 and 14. The most common abnormality was a marker 14q+ (breakpoint 14q32) seen in 17 cases; trisomy 12 was observed in seven cases. A clinical scoring system was used to investigate the correlation of chromosome abnormalities with prognosis. The group with 14q+ was often associated with features of progressive disease, namely; prolymphocytoid or Richter transformation, refractoriness to therapy, high WBC and advanced staging. A significant difference in survival was observed between patients with 14q+ and the rest: median survival from diagnosis being 45 months and over 64 months, respectively (P less than 0.05); when survival was calculated from the time of chromosome analysis the values were 8 months and more than 41 months, respectively (P less than 0.01). It is suggested that 14q+ is acquired during the evolution of CLL and that this development may be a key event in the clinical progression of B-CLL. Other abnormalities, including trisomy 12, were not found to be associated with a worse prognosis.

Chromosome abnormalities in B-cell prolymphocytic leukemia: a study of nine cases

Chromosome abnormalities were demonstrated in 50-100% of Giemsa-banded metaphases from nine cases of B-cell prolymphocytic leukemia (B-PLL). Mitoses were obtained with pokeweed mitogen following pretreatment of peripheral blood (PB) prolymphocytes with neuraminidase-galactose oxidase. Chromosome 14 was abnormal in eight of the nine cases: a marker 14q+, with breakpoint at band q32 in seven and trisomy 14 in one. In four cases the abnormal No. 14 was one of several primary abnormalities and in four others it was seen in secondary clones. The origin of the translocated material was unknown in three cases, in two it resulted from t(11;14), later becoming t(11;14;21) in one of them, t(1;14) in another, progressing later to t(1;14;17); in yet another patient, the 14q+ was the result of a complex rearrangement t(6;14;17). Abnormalities of chromosome 6 were seen in six cases: 6q- as the primary abnormality in three; trisomy 6 was part of secondary changes in one case. Structural abnormalities of chromosome 1 were seen in six cases: 1q- in four (in one as the only abnormality), 1q+ in one case, and 1p- in another, both in the main clone. Trisomy 12 was demonstrated in three cases but not as the primary change. Spleen cells in two patients showed a higher frequency of abnormalities than in the PB, supporting the concept of the spleen being the organ primarily involved in B-PLL. Evidence of karyotypic evolution was demonstrated in six patients, in some clearly associated with clinical progression of the disease. The type and frequency of the abnormalities observed in B-PLL resemble those seen in non-Hodgkin's lymphomas and suggest major differences from B-CLL, although a relationship with the latter can not be completely ruled out at present.

Chronic T-cell leukemias. II. Cytogenetic studies

Chromosome abnormalities were documented in the PHA-stimulated lymphoid cells from 10 patients with chronic T-cell leukemias (6 T-PLL, 3 T-CLL and 1 T-LCL). One or more marker chromosomes were present in most metaphases in every case of T-PLL but they were different in each case. Structural abnormalities were also observed in T-CLL and T-LCL but less consistently. Chromosomes involved in marker formation in two or more cases were: Nos. 2, 7, 8, 9, 11 and 16. The karyotype was hypodiploid in five cases and hyperdiploid in two. Chromosomes Nos. 2 and 8 were the most frequently involved in structural and numerical abnormalities: Nos. 8 in 2 T-CLL and the 6 T-PLL and No. 2 in 1 T-CLL, 1 T-LCL and 5 T-PLL. Abnormalities of chromosome No. 2 are rare in human neoplastic disease but may be common in T-lymphoproliferative disorders. The differences between T-PLL and T-CLL reported here may have some bearing on the clinical features. T-PLL, characterised in all cases by clonal abnormalities, has an aggressive clinical course. In contrast, T-CLL with less consistent karyotypic changes has a protracted and benign clinical evolution.

Stimulation of chronic lymphatic leukaemia cells by pokeweed mitogen after treatment with neuraminidase-galactose oxidase

CLL lymphocytes gave a low response upon stimulation with PHA or PWM in 3-day cultures. However, after treatment with neuraminidase-galactose oxidase (NGO), in the presence of PWM, CLL lymphocytes transformed into blasts and incorporated 3H-thymidine in 3-day cultures. This response of CLL lymphocytes was similar to that given by normal lymphocytes to PWM in 3-day cultures. The best stimulation of CLL lymphocytes was achieved when conditioned medium (CM) from normal T lymphocytes was present in PWM cultures. Purified B lymphocytes from CLL (T lymphocytes and monocytes removed) did not respond to PHA or PWM. However, after NGO treatment these cells were stimulated by PWM, but only in the presence of CM. PHA failed to stimulate NGO-treated CLL lymphocytes or purified B lymphocytes. This study shows that CLL lymphocytes, which usually fail to respond to mitogens, can be stimulated by PWM to proliferate after treatment with neuraminidase-galactose oxidase (NGO). This technique of B cell stimulation has been found useful in cytogenetic studies of B cell proliferative disorders.

Esculin hydrolysis by Enterobacteriaceae

Literature reports disagree concerning esculin hydrolysis in the family Enterobacteriaceae. A total of 2,490 strains of the family were investigated for esculin hydrolysis by two methods, the esculin spot test and the PathoTec incubation strip, which measures constitutive enzyme, and five growth-supporting methods, which determine both constitutive and inducible enzymes. The five growth-supporting media studied were: Vaughn-Levine, the standard esculin hydrolysis medium (P. R. Edwards and W. H. Ewing, Identification of Enterobacteriaceae, 3rd ed., 1972); Vaughn-Levine without iron; Vaughn-Levine without Andrade's indicator; and bile-esculin medium. Growth media were incubated at 35 degrees C and checked every 24 h for 120 h. On growth media, 0.3% of Escherichia coli were positive in 24 h, 34% in 48 h, and 61% in 120 h. No strains were positive on the "nongrowth" tests. It appeared that the esculin hydrolysis enzyme(s) of E. coli was inducible rather than constitutive. All esculin hydrolyzers, which yielded positive tests on "constitutive tests" and 24-h tests, were limited to the genera Klebsiella, Enterobacter, and Serratia and species of Proteus vulgaris, Proteus rettgeri, and Citrobacter diversus. When used with standardized inoculum size and incubation time, the esculin hydrolysis test is very useful for differentiation within the family Enterobacteriaceae.

The use of bile - esculin agar for the taxonomic classification of the family Enterobacteriaceae

Bile-esculin medium has been used for many years for the presumptive identification of group D Streptococcus. The test is based on the ability of a bacterium to grow in the presence of 40% bile and produce esculinase. 2935 strains of Enterobacteriaceae were inoculated onto bile-esculin agar slants and incubated at 35 C. Esculin hydrolysis was determined after 24 and 48 hours. At 24 hours of incubation esculin hydrolysis was limited to the genera Klebsiella, Enterobacter, Serratia, and the species P. vulgaris, P. rettgeri, and C. diversus. Not all strains of these species were positive, however. All other members of the family were negative. At 48 hours of incubation 37% of E. coli gave a positive reaction; all other Enterobacteriaceae which were negative at 24 hours remained negative. Esculin hydrolysis is a valuable test for the taxonomic classification of the family Enterobacteriaceae.