The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

BACKGROUND

The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications.

METHODS

ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery.

RESULTS

The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784.

CONCLUSIONS

This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance.

CLINICAL TRIAL REGISTRATION

NCT03044899.

Immunoexpression of tenascin as a predictor of the malignancy potential of oral leukoplakia associated with a tobacco habit

Oral leukoplakia is a morphological alteration of tissue that is an early indicator for malignancy. Tenascin (TN) is a large hexameric extracellular matrix (ECM) protein with anti-adhesive properties that fosters cell migration during development, wound healing and tissue remodeling; it is present in small amounts in adult tissues. Overexpression of TN in a pathological condition may be either a cause or a consequence of the disease. We evaluated the efficacy of TN for early prediction of tobacco-associated oral cancers. We studied retrospectively 95 cases of oral leukoplakia, including mild, moderate and severe cases, using immunohistochemistry for TN. We evaluated the intensity, area and pattern of TN expression. Greater intensity and area of TN expression was observed in mild and severe dysplasia than in moderate dysplasia. Most cases showed a reticular pattern of expression, especially in mild and moderate dysplasia; a fibrillar pattern was more evident in severe dysplasia. We also observed homogeneous expression pattern in some cases. TN is a marker for dysplastic changes in epithelium and its expression may be helpful for predicting the malignancy potential of tobacco-associated oral leukoplakia.

PCR based detection of HPV 16 and 18 genotypes in normal oral mucosa of tobacco users and non-users

There is increasing evidence of a causal association between human papillomavirus (HPV) and oral squamous cell carcinoma (OSCC). Several studies have shown that HPV is associated with increased risk of oral cancer independent of exposure to tobacco and alcohol. The association is valid for HPVs 16 and 18, which generally are considered high risk types, because they have been detected in oral dysplastic lesions and cancers. We determined the baseline prevalence of HPVs 16 and 18 in normal oral mucosa of individuals with and without tobacco habit. PCR was used for DNA collected by oral smears to detect HPV 16/18 DNA in normal oral mucosa of 60 healthy individuals who were assigned to two groups of 30 subjects each. One group had a tobacco habit, the other did not. The tobacco user group comprised individuals who were tobacco chewers only. Sixty-five percent of individuals were positive for HPV 16/18 DNA, but HPV 16/18 positivity was less in individuals with tobacco habit than in those without tobacco habit. No significant association was found between the presence of HPVs and gender, age or duration of chewing habit, or between groups with and without a tobacco habit. We propose that HPVs16 and 18 commonly are present in normal oral mucosa and emphasize the importance of distinguishing clinical, subclinical and latent HPV infections when investigating HPVs and OSCC.

Immunohistochemical expression of TLR4 and TLR9 in various grades of oral epithelial dysplasia and squamous cell carcinoma, and their roles in tumor progression: a pilot study

Toll-like receptors (TLRs) play an essential role in the activation of innate immunity. TLRs are expressed in B-lymphocytes, monocytes, dendritic cells and epithelial cells. We examined the immunohistochemical expressions of TLR4 and TLR9 in various grades of oral epithelial dysplasia (OED), oral squamous cell carcinoma (OSCC) and normal oral mucosa (NOM) to determine the association between TLR4 and TLR9 in the progression of lesions from dysplasia to carcinoma. Expressions of TLR4 and TLR9 were assessed using immunohistochemistry (IHC) on paraffin embedded tissue blocks of various grades of OED (28 cases), OSCC (27 cases) and NOM (10 cases). Expression of TLR4 was high in all grades of OED and OSCC. Expression of TLR9 was high in well differentiated squamous cell carcinoma and moderately differentiated squamous cell carcinomas, and moderate to low in poorly differentiated squamous cell carcinomas. Although expression was high in case of TLR4, it was not statistically significant. Expression of TLR9 was statistically significant. In OED, expression of TLR9 was less than that of TLR4. Our results indicated that the pattern of expression of TLR4 and TLR9 increased significantly from mild to severe dysplasia compared to controls. Expression of TLR4 and TLR9 reflects progression of OED to OSCC, which suggests that TLR may play a role in tumorigenesis and that it could be used as a target for OSCC prevention and therapy in the future.

Microbial contamination of "In use" bar soap in dental clinics

Bar soap from 18 different dental clinics were investigated for microbial contamination, while it was "in-use". Of the 32 samples obtained from the bar soap, 100% yielded positive culture. A total of 8 different genera of organisms were isolated. Each bar soap was found to harbor 2-5 different genera of micro organisms. Heavily used soap had more micro organisms compared to less used soap. The microbial load of the "in-use" bar soap constituted a mixed flora of gram positive, gram negative, aerobes, anaerobes, and fungi. The results indicate that the bar soap under "in-use" condition is a reservoir of microorganisms and handwashing with such a soap may lead to spread of infection.

Perceived food and drug allergies in functional and organic gastrointestinal disorders

BACKGROUND

Gastrointestinal symptoms are often due to functional disorders. Many individuals with abdominal symptoms believe they are allergic to or intolerant of various foods.

AIM

To assess whether self-reported allergy is linked to a subsequent functional or organic diagnosis.

METHODS

One thousand new patients attending a district hospital gastroenterology clinic completed a questionnaire about believed drug and food allergies and foodstuffs thought to worsen symptoms. No attempt was made to confirm patients' self-reported allergies or intolerances. Final diagnoses were classified as organic or functional.

RESULTS

Nineteen per cent of patients reported drug allergies, 14% reported food allergies and 30% identified foods that worsened symptoms. Atopic patients reported more allergies. Forty-eight per cent of patients had a functional diagnosis. Women were twice as likely as men to have a functional diagnosis. Patients subsequently diagnosed with a functional disorder were more likely than those with organic disease to report drug allergies (odds ratio, 1.92; 95% confidence interval (CI), 1.39-2.65), food allergies (odds ratio, 4.14; 95% CI, 2.73-6.26) or foods that worsened their abdominal symptoms (odds ratio, 3.08; 95% CI, 2.31-4.10). The likelihood of symptoms being functional increased even further if adverse reactions to both drugs and foods were reported. Patients with weight gain were more likely to report food allergy, and those with both features were very likely to have a functional disorder (odds ratio, 4.58; 95% CI, 3.08-6.86).

CONCLUSIONS

Patients with gastrointestinal symptoms who report drug or food allergies or worsening of symptoms with various foods are more likely to have functional than organic illness. Enquiry about perceived allergies and intolerances may help in the early identification of functional gastrointestinal disorders.

The effect of HIV disease on serum markers of hepatitis delta infection in intravenous drug abusers

The prevalence of serum markers of delta hepatitis was determined prospectively in 82 intravenous drug abusers at various stages of human immunodeficiency virus (HIV) disease. Seventeen were HIV negative, 30 were HIV positive without acquired immunodeficiency syndrome (AIDS) and 35 had been diagnosed as having AIDS. Antihepatitis D virus (HDV) in serum was measured by a commercially available enzyme-linked immunosorbent assay (ELISA) and also by solid phase capture radioimmunoassays (RIAs) for immunoglobulin G (IgG) and immunoglobulin M (IgM) anti-HDV. HDV antigen and hepatitis B virus (HBV) DNA were also measured. Hepatitis B surface antigen (HBsAg) and anti-HBs were determined by using a commercially available RIA. Anti-HDV (RIA) was only detected in serum that contained HBsAg. These anti-HDV (RIA) positive samples also tested positive with the commercial anti-HDV electroimmunoassay. In addition, the commercial anti-HDV ELISA detected anti-HDV in some serum samples that were negative for HBsAg; these anti HDV-positive HBsAg-negative samples were frequently lipemic or contained rheumatoid factor. The prevalence of HBsAg and anti-HBs did not differ significantly with the stage of HIV disease. HBsAg was detected in 3 of 13 (23%) HIV-negative, 5 of 29 (17%) HIV-positive, and 4 of 18 (22%) patients with AIDS. IgG and IgM anti-HDV (RIA) was positive in 2 of 3 HIV-negative and 4 of 5 HIV-positive pre-AIDS HBsAg-positive subjects. However, none of 4 AIDS patients had anti-HDV. The difference between AIDS and non-AIDS patients was statistically significant (Fisher's exact test, p = 0.03). HDV antigen was detected in serum from one AIDS patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Event-related potentials in the dual task paradigm: P300 discriminates engaging and non-engaging films when film-viewing is the primary task

Five groups of subjects (11-16/group) were run in three experiments. In each study P300 amplitude and latency were studied as a function of three sensory task conditions: (1) baseline (oddball task: target and non-target tones only); (2) boring film viewing plus oddball task; and (3) exciting film viewing plus oddball task. In Experiment I, target probability was P = 0.22. In Experiments II and III, each of two groups of subjects was run at P = 0.22 or P = 0.33. Two different exciting films and two different boring films were used. Oddball-target amplitude was found to consistently decrease from baseline to boring to exciting film-viewing conditions at P = 0.22. At P = 0.33, the 2-film discrimination was successful in one of two experiments. P300 amplitude consistently differed from baseline to film-viewing conditions. For the non-target (frequent) tones, the smaller P300 amplitudes consistently discriminated boring and exciting films, as well as single from dual tasks. For target P300 latency, single (baseline) and dual (film-watching) conditions were always discriminable, but boring and exciting films were not discriminable. There were no effects on non-target P300 latency. N100 amplitude discriminated baseline and film viewing conditions, but not boring and engaging films.

Coronary artery stenting after angioplasty with self-expanding parallel wire metallic stents

Parallel wire stents were implanted over exchange guide wires at percutaneous transluminal coronary angioplasty sites in 27 canine coronary arteries that were predilated with slightly oversized balloons. Stents were stainless steel, self-expandable, 3.5 to 4.5 mm in diameter, 9 to 12 mm in length, and were made of 10 wires that were longitudinally laser-welded in a zig-zag design. The compressible stent was delivered by the withdrawal of a Teflon outer catheter (4.2 to 4.9F) and the push of a polyethylene inner catheter. Aspirin, 80 mg per day, was given from the day before the study began, and heparin (150 U/kg) was administered during implantation. Quantitative angiography and pathologic examinations were performed at day 0 and at weeks 2, 4, 12, 26 and 52. The coronary angiographic diameter at the stent site immediately after stenting marginally increased from diameter before stenting: 3.22 +/- 0.40 mm versus 3.14 +/- 0.37 mm (p = 0.03), and during a mean of 14 weeks of follow-up, remained unaltered from immediate post-stenting: 3.29 +/- 0.43 mm versus 3.22 +/- 0.40 mm (p = NS) with no stent displacement. Comparisons of patency and thrombosis between heparin-coated and uncoated stents, between left anterior descending and circumflex arteries, and among the three different diameters of stents showed uniformly good results. At microscopy, the wires were oriented perfectly and embedded in the arterial wall, and by 2 weeks they were covered by mucopolysaccharide ground substance, smooth muscle cells, and an almost complete monolayer of neoendothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional cloning of mouse chromosomal loci specifically active in embryonal carcinoma stem cells

Chromosomal loci that are specifically active in embryonal carcinoma stem cells were cloned from the mouse genome by functional selection. P19 cells, a pluripotent embryonal carcinoma cell line, were transfected with an enhancer trap (a plasmid containing an enhancerless inactive neo gene), and NEO+ transformants were isolated. All of the NEO+ cell lines retained pluripotency and expressed the neo gene. When the cells were induced to differentiate, most of the cell lines continued to express the neo gene, while the neo gene in some cell lines became repressed. From the latter group of cell lines, we have cloned the integrated neo gene plus the flanking cellular DNA sequences. Three of the six cloned DNAs possessed a high NEO+-transforming activity in undifferentiated P19 cells. Among these three, two (015 and 052) were inactive in differentiated P19 cells and NIH 3T3 cells, while the remaining one was active in these differentiated cells. Deletion analysis suggested that both 015 and 052 contain two regulatory elements (promoter and enhancer) of cellular DNA origin. The putative enhancer and promoter are separated by at least 6 kilobases in 015 and 1 kilobase in 052. Therefore, 015 and 052 cloned fragments contain regulatory DNA elements that are specifically active in the embryonal carcinoma stem cells.

Synthesis of side chain-modified iodothyronines

New side chain-modified iodothyronines have been synthesized. They include: 1-[4-(4-hydroxyphenoxy)-3,5-diiodophenyl]-1,2-ethanediol (T2EG); alpha-hydroxy-4-(4-hydroxyphenoxy)-3,5-diiodobenzeneacetic acid (T2HAA) and their 4-methyl ether derivatives (MT2EG, MT2HAA); 1-[4-(4-hydroxyphenoxy)-3,5-diiodophenyl]-2-aminoethanol (T2EA); 1-[4-(4-hydroxy-3-iodophenoxy)-3,5-diiodophenyl]-1,2-ethaned iol (T3EG); 1-[4-(4-hydroxy-3-iodophenoxy)-3,5-diiodophenyl]-2-aminoetha nol (T3EA); and alpha-hydroxy-4-(3-iodo-4-hydroxyphenoxy)-3,5-diiodobenzeneacet ic acid (T3HAA). These model compounds are being used to study thyroid hormone metabolism and to determine structure-activity relationships of iododiphenylether derivatives.

Characterization of a cell type-specific enhancer found in the human papilloma virus type 18 genome

We have previously isolated long-range acting enhancer elements from the HeLa genome by functional selection. In this report, the structural and functional characteristics of one (GA1) of the enhancers are reported. By cloning various restriction fragments and by deletion mutagenesis, the activity of GA1 was located in a 230-bp region. The nucleotide sequence of GA1 and genomic Southern blot analysis indicated that GA1 is derived from human papilloma virus (HPV) 18 DNA that had been integrated into the HeLa genome. The enhancer is located in the non-coding region of the HPV 18 genome. The HPV 18 enhancer consists of two functional domains, both of which have full enhancer activity in HeLa cells. The enhancer does not contain enhancer core sequences but contains several blocks of potential Z-DNA sequence. Like SV40 and polyoma virus enhancers, the activity of the HPV 18 enhancer was repressed by adenovirus E1a products. The HPV 18 enhancer shows a narrow cell type specificity: it is active in some cervical carcinoma cell lines, but inactive in all non-cervical cells except for one neuroblastoma cell line. These results suggest that the HPV 18 enhancer plays an important role in regulation of the viral genes.

Evaluation of lung sounds by telephone

We evaluated the utility of a newly designed electronic stethoscope that can be used with the telephone system. Nine patients with wheezing, crackles, or other adventitious sounds were evaluated by a physician examiner who used a conventional stethoscope and another physician who received the signal of the electronic stethoscope via telephone. When their findings were compared, it was found that physicians agreed in 95% of observations. The potential uses of the electronic stethoscope are discussed.

Anaphylactic reaction on subsequent exposure to Cuprophan-Hollow Fiber Dialyzer: a case report

A 55-year-old black female was dialyzed with Cuprophan dialyzers twenty times without complications. Upon re-exposure eight months later she developed a severe anaphylactic reaction characterized by hypotension, shortness of breath and subsequent cardiopulmonary arrest. She did not have significant adverse reactions to Cordis-Dow-Hollow-Fiber dialyzers.