Sex-based Differences in the Phenotypic Expression and Prognosis of Idiopathic Non-ischemic Cardiomyopathy: A Cardiovascular Magnetic Resonance Study

AIMS

We sought to characterize sex-related differences in CMR-based cardiovascular phenotypes and prognosis in patients with idiopathic non-ischemic cardiomyopathy (NICM).

METHODS AND RESULTS

Patients with NICM enrolled in the Cardiovascular Imaging Registry of Calgary (CIROC) between 2015 and 2021 were identified. Z-score values for chamber volumes and function were calculated as standard deviation from mean values of 157 sex-matched healthy volunteers, ensuring reported differences were independent of known sex-dependencies. Patients were followed for the composite outcome of all-cause mortality, heart failure admission, or ventricular arrhythmia.A total of 747 patients were studied, 531 (71%) males. By Z-score values, females showed significantly higher left ventricular (LV) ejection fraction (EF; median difference 1 SD) and right ventricular (RV) EF (difference 0.6 SD) with greater LV mass (difference 2.1 SD; p-value<0.01 for all) versus males despite similar chamber volumes. Females had a significantly lower prevalence of mid-wall striae (MWS) fibrosis (23% versus 36%; p-value<0.001). Over a median follow-up of 4.7 years, 173 patients (23%) developed the composite outcome, with equal distribution in males and females. LV EF and MWS were significant independent predictors of the outcome (respective HR [95% CI] 0.97 [0.95-0.99] and 1.6 [1.2-2.3]; p-value=0.003 and 0.005). There was no association of sex with the outcome.

CONCLUSIONS

In a large contemporary cohort, NICM was uniquely expressed in females versus males. Despite similar chamber dilation, females demonstrated greater concentric remodelling, lower reductions in bi-ventricular function, and a lower burden of replacement fibrosis. Overall, their prognosis remained similar to male patients with NICM.

Development of a risk prediction model for Barrett's esophagus in an Australian population

Esophageal adenocarcinoma has poor 5-year survival rates. Increased survival might be achieved with earlier treatment, but requires earlier identification of the precursor, Barrett's esophagus. Population screening is not cost effective, this may be improved by targeted screening directed at individuals more likely to have Barrett's esophagus. To develop a risk prediction tool for Barrett's esophagus, this study compared individuals with Barrett's esophagus against population controls. Participants completed a questionnaire comprising 35 questions addressing medical history, symptom history, lifestyle factors, anthropomorphic measures, and demographic details. Statistical analysis addressed differences between cases and controls, and entailed initial variable selection, checking of model assumptions, and establishing calibration and discrimination. The area under the curve (AUC) was used to assess overall accuracy. One hundred and twenty individuals with Barrett's esophagus and 235 population controls completed the questionnaire. Significant differences were identified for age, gender, reflux history, family reflux history, history of hypertension, alcoholic drinks per week, and body mass index. These were used to develop a risk prediction model. The AUC was 0.82 (95% CI 0.78-0.87). Good calibration between predicted and observed risk was noted (Hosmer-Lemeshow test P = 0.67). At the point minimizing false positives and false negatives, the model achieved a sensitivity of 84.96% and a specificity of 66%. A well-calibrated risk prediction model with good discrimination has been developed to identify patients with Barrett's esophagus. The model needs to be externally validated before consideration for clinical practice.

Risk factors for delayed gastric emptying following laparoscopic repair of very large hiatus hernias

Background

Delayed gastric emptying can complicate surgery for hiatus hernia. The aim of this study was to quantify its incidence following laparoscopic repair of very large hiatus hernias, identify key risk factors for its occurrence and determine its impact on clinical outcomes.

Methods

Data collected from a randomized trial of patients who underwent laparoscopic mesh versus sutured repair of very large hiatus hernias (more than 50 per cent of stomach in chest) were analysed retrospectively. Delayed gastric emptying was defined as endoscopic evidence of solid food in the stomach after fasting for 6 h at 6 months after surgery.

Results

Delayed gastric emptying occurred in 19 of 102 patients (18·6 per cent). In univariable analysis, type 2 paraoesophageal hernia (relative risk (RR) 3·15, 95 per cent c.i. 1·41 to 7·06), concurrent anterior and posterior hiatal repair (RR 2·66, 1·14 to 6·18), hernia sac excision (RR 4·85, 1·65 to 14·24), 270°/360° fundoplication (RR 3·64, 1·72 to 7·68), division of short gastric vessels (RR 6·82, 2·12 to 21·90) and revisional surgery (RR 3·69, 1·73 to 7·87) correlated with delayed gastric emptying. In multivariable analysis, division of short gastric vessels (RR 6·27, 1·85 to 21·26) and revisional surgery (RR 6·19, 1·32 to 28·96) were independently associated with delayed gastric emptying. Delayed gastric emptying correlated with adverse gastrointestinal symptomatology, including higher rates of bloating, nausea, vomiting and anorexia, as well as reduced patient satisfaction with the operation and recovery.

Conclusion

Delayed gastric emptying following large hiatus hernia repair is common and associated with adverse symptoms and reduced patient satisfaction. Division of short gastric vessels and revisional surgery were independently associated with its occurrence.

Venous thromboembolism in patients with esophageal or gastric cancer undergoing neoadjuvant chemotherapy

There is a well-established link between cancer and venous thromboembolism (VTE), and patients receiving chemotherapy for esophageal or gastric cancer appear at high risk of developing VTE. The incidence of VTE in the neoadjuvant setting in these patients is poorly understood, as is the role for thromboprophylaxis during neoadjuvant chemotherapy. A PubMed search was conducted using a combination of terms including; esophageal & gastric cancer, deep venous thrombosis (DVT), VTE, neoadjuvant, chemotherapy and chemoradiotherapy. One hundred and fifty-four articles were retrieved and a narrative review was conducted. For patients with esophageal and gastric cancer the incidence of VTE ranged from 4 to 19%. Gastric cancer (Odds Ratio [OR] 6.38, [95% CI: 1.96-20.80]) and Stage III/IV disease, (OR 5.16 [95% CI: 1.29-20.73]) were identified as risk factors for developing VTE. Neoadjuvant chemotherapy was identified as an independent risk factor for developing VTE. Symptomatic and asymptomatic VTE have a similar effect on mortality. Median overall survival for asymptomatic VTE was 13.9 months (95% CI: 5.0-∞) versus 12.8 months (95% CI: 4.7-30.3) if the VTE was symptomatic. Neoadjuvant chemotherapy is a significant risk factor for VTE in patients with esophageal and gastric cancer. Intervention to minimize the risk using pharmacological and mechanical thromboprophylaxis should be considered, and this should start in the neoadjuvant period.

Evaluation of outcome after cardiomyotomy for achalasia using the Chicago classification

Background

Achalasia can be subdivided into manometric subtypes according to the Chicago classification. These subtypes are proposed to predict outcome after treatment. This hypothesis was tested using a database of patients who underwent laparoscopic Heller's cardiomyotomy with anterior fundoplication.

Methods

All patients who underwent Heller's cardiomyotomy for achalasia between June 1993 and March 2015 were identified from an institutional database. Manometry tracings were retrieved and re-reported according the Chicago classification. Outcome was assessed by a postal questionnaire, and designated a success if the modified Eckardt score was 3 or less, and the patient had not undergone subsequent surgery or pneumatic dilatation. Difference in outcome after cardiomyotomy was analysed with a mixed-effects logistic regression model.

Results

Sixty, 111 and 24 patients had type I, II and II achalasia respectively. Patients with type III achalasia were more likely to be older than those with type I or II (mean age 63 versus 50 and 49 years respectively; P = 0·001). Some 176 of 195 patients returned questionnaires after surgery. Type III achalasia was less likely to have a successful outcome than type II (odds ratio (OR) 0·38, 95 per cent c.i. 0·15 to 0·94; P = 0·035). There was no significant difference in outcome between types I and II achalasia (II versus I: OR 0·87, 0·47 to 1·60; P 0·663). The success rate at 3-year follow-up was 69 per cent (22 of 32) for type I, 66 per cent (33 of 50) for type II and 31 per cent (4 of 13) for type III.

Conclusion

Type III achalasia is a predictor of poor outcome after cardiomyotomy. There was no difference in outcome between types I and II achalasia.

Molecular physiognomies and applications of adipose-derived stem cells

Adipose-derived stromal/stem cells (ASC) are multipotent with abilities to differentiate into multiple lineages including connective tissue and neural cells. Despite unlimited opportunity and needs for human and veterinary regenerative medicine, applications of adipose-derived stromal/stem cells are at present very limited. Furthermore, the fundamental biological factors regulating stemness in ASC and their stable differentiation into other tissue cells are not fully understood. The objective of this review was to provide an update on the current knowledge of the nature and isolation, molecular and epigenetic determinants of the potency, and applications of adipose-derived stromal/stem cells, as well as challenges and future directions. The first quarter of the review focuses on the nature of ASC, namely their definition, origin, isolation and sorting methods and multilineage differentiation potential, often with a comparison to mesenchymal stem cells of bone marrow. Due to the indisputable role of epigenetic regulation on cell identities, epigenetic modifications (DNA methylation, chromatin remodeling and microRNAs) are described broadly in stem cells but with a focus on ASC. The final sections provide insights into the current and potential applications of ASC in human and veterinary regenerative medicine.

Novel handheld magnetometer probe based on magnetic tunnelling junction sensors for intraoperative sentinel lymph node identification

Using magnetic tunnelling junction sensors, a novel magnetometer probe for the identification of the sentinel lymph node using magnetic tracers was developed. Probe performance was characterised in vitro and validated in a preclinical swine model. Compared to conventional gamma probes, the magnetometer probe showed excellent spatial resolution of 4.0 mm, and the potential to detect as few as 5 μg of magnetic tracer. Due to the high sensitivity of the magnetometer, all first-tier nodes were identified in the preclinical experiments, and there were no instances of false positive or false negative detection. Furthermore, these preliminary data encourage the application of the magnetometer probe for use in more complex lymphatic environments, such as in gastrointestinal cancers, where the sentinel node is often in close proximity to other non-sentinel nodes, and high spatial resolution detection is required.

Twenty years of experience with laparoscopic antireflux surgery

BACKGROUND

There are few reports of large patient cohorts with long-term follow-up after laparoscopic antireflux surgery. This study was undertaken to evaluate changes in surgical practice and outcomes for laparoscopic antireflux surgery over a 20-year period.

METHODS

A standardized questionnaire, prospectively applied annually, was used to determine outcome for all patients undergoing laparoscopic fundoplication in two centres since commencing this procedure in 1991. Visual analogue scales ranging from 0 to 10 were used to assess symptoms of heartburn, dysphagia and satisfaction with overall outcome. Data were analysed to determine outcome across 20 years.

RESULTS

From 1991 to 2010, 2261 consecutive patients underwent laparoscopic fundoplication at the authors' institutions. Follow-up ranged from 1 to 19 (mean 7.6) years. Conversion to open surgery occurred in 73 operations (3.2 per cent). Revisional surgery was performed in 216 patients (9.6 per cent), within 12 months of the original operation in 116. There was a shift from Nissen to partial fundoplication across 20 years, and a recent decline in operations for reflux, offset by an increase in surgery for large hiatus hernia. Dysphagia and satisfaction scores were stable, and heartburn scores rose slightly across 15 years of follow-up. Heartburn scores were slightly higher and reoperation for reflux was more common after anterior partial fundoplication (P = 0.005), whereas dysphagia scores were lower and reoperation for dysphagia was less common (P < 0.001). At 10 years, satisfaction with outcome was similar for all fundoplication types.

CONCLUSION

Laparoscopic Nissen and partial fundoplications proved to be durable and achieved good long-term outcomes. At earlier follow-up, dysphagia was less common but reflux more common after anterior partial fundoplication, although differences had largely disappeared by 10 years.

Post-fundoplication contrast studies: is there room for improvement?

OBJECTIVE

Since the mid-1990s, laparoscopic fundoplication for gastro-oesophageal reflux disease has become the surgical procedure of choice. Several surgical groups perform routine post-operative contrast studies to exclude any (asymptomatic) anatomical abnormality and to expedite discharge from hospital. The purpose of this study was to determine the accuracy and interobserver reliability for surgeons and radiologists in contrast study interpretation.

METHODS

11 surgeons and 13 radiologists (all blinded to outcome) retrospectively reviewed the contrast studies of 20 patients who had undergone a laparoscopic fundoplication. Each observer reported on fundal wrap position, leak or extravasation of contrast and contrast hold-up at the gastro-oesophageal junction (on a scale of 0-4). A κ coefficient was used to evaluate interobserver reliability.

RESULTS

Surgeons were more accurate than radiologists in identifying normal studies (specificity = 91.6% vs 78.9%), whereas both groups had similar accuracy in identifying abnormal studies (sensitivity = 82.3% vs 85.2%). There was higher agreement amongst surgeons than amongst radiologists when determining wrap position (κ = 0.65 vs 0.54). Both groups had low agreement when classifying a wrap migration as partial or total (κ = 0.33 vs 0.06). Radiologists were more likely to interpret the position of the wrap as abnormal (relative risk = 1.25) while surgeons reported a greater degree of hold-up of contrast at the gastro-oesophageal junction (mean score = 1.17 vs 0.86).

CONCLUSION

Radiologists would benefit from more information about the technical details of laparoscopic anti-reflux surgery. Standardised protocols for performing post-fundoplication contrast studies are needed.

Impact of ineffective oesophageal motility and wrap type on dysphagia after laparoscopic fundoplication

BACKGROUND

Laparoscopic 360° fundoplication is the most common operation for gastro-oesophageal reflux disease, but is associated with postoperative dysphagia in some patients. Patients with ineffective oesophageal motility may have a higher risk of developing postoperative dysphagia, but this remains unclear.

METHODS

From 1991 to 2010, 2040 patients underwent primary laparoscopic fundoplication for gastro-oesophageal reflux disease and met the study inclusion criteria; 343 had a 90°, 498 a 180° and 1199 a 360° fundoplication. Primary peristalsis and distal contraction amplitude during oesophageal manometry were determined for 1354 patients. Postoperative dysphagia scores (range 0-45) were recorded at 3 and 12 months, then annually. Oesophageal dilatations and/or reoperations for dysphagia were recorded.

RESULTS

Preoperative oesophageal motility did not influence postoperative dysphagia scores, the need for dilatation and/or reoperation up to 6 years. Three-month dysphagia scores were lower after 90° and 180° compared with 360° fundoplication (mean(s.e.m.) 8·0(0·6) and 9·8(0·5) respectively versus 11·9(0·4); P < 0·001 and P = 0·003), but these differences diminished after 6 years of follow-up. The incidence of dilatation and reoperation for dysphagia was lower after 90° (2·6 and 0·6 per cent respectively) and 180° (4·4 and 1·0 per cent) fundoplications than with a 360° wrap (9·8 and 6·8 per cent; both P < 0·001 versus 90° and 180° groups).

CONCLUSION

Tailoring the degree of fundoplication according to preoperative oesophageal motility by standard manometric parameters has no long-term impact on postoperative dysphagia. There is, however, a proportionate increase in short-term dysphagia scores with increasing degree of wrap, and a corresponding proportionate increase in dilatations and reoperations for dysphagia. These differences in dysphagia scores diminish with time.

Diffuse esophageal leiomyomatosis

Progressive dysphagia of unknown etiology may still provide a diagnostic challenge despite an increase in the number and quality of investigations available. We describe a 64-year-old man who presented with progressive dysphagia and weight loss. Following a number of investigations, a diagnosis of diffuse esophageal leiomyomatosis was made and the patient was treated appropriately.

Risk prediction scores for postoperative mortality after esophagectomy: validation of different models

BACKGROUND

Different prediction models for operative mortality after esophagectomy have been developed. The aim of this study is to independently validate prediction models from Philadelphia, Rotterdam, Munich, and the ASA.

METHODS

The scores were validated using logistic regression models in two cohorts of patients undergoing esophagectomy for cancer from Switzerland (n = 170) and Australia (n = 176).

RESULTS

All scores except ASA were significantly higher in the Australian cohort. There was no significant difference in 30-day mortality or in-hospital death between groups. The Philadelphia and Rotterdam scores had a significant predictive value for 30-day mortality (p = 0.001) and in-hospital death (p = 0.003) in the pooled cohort, but only the Philadelphia score had a significant prediction value for 30-day mortality in both cohorts. Neither score showed any predictive value for in-hospital death in Australians but were highly significant in the Swiss cohort. ASA showed only a significant predictive value for 30-day mortality in the Swiss. For in-hospital death, ASA was a significant predictor in the pooled and Swiss cohorts. The Munich score did not have any significant predictive value whatsoever.

CONCLUSION

None of the scores can be applied generally. A better overall predictive score or specific prediction scores for each country should be developed.

Long-term outcomes of revisional surgery following laparoscopic fundoplication

Background

A small proportion of patients who have laparoscopic antireflux procedures require revisional surgery. This study investigated long-term clinical outcomes.

Methods

Patients requiring late revisional surgery following laparoscopic fundoplication for gastro-oesophageal reflux were identified from a prospective database. Long-term outcomes were determined using a questionnaire evaluating symptom scores for heartburn, dysphagia and satisfaction.

Results

The database search found 109 patients, including 98 (5·6 per cent) of 1751 patients who had primary surgery in the authors' unit. Indications for surgical revision were dysphagia (52 patients), recurrent reflux (36), mechanical symptoms related to paraoesophageal herniation (16) and atypical symptoms (five). The median time to revision was 26 months. Outcome data were available for 104 patients (median follow-up 66 months) and satisfaction data for 102, 88 of whom were highly satisfied (62·7 per cent) or satisfied (23·5 per cent) with the outcome. Patients who had revision for dysphagia had a higher incidence of poorly controlled heartburn (20 versus 2 per cent; P = 0·004), troublesome dysphagia (16 versus 6 per cent; P = 0·118) and a lower satisfaction score (P = 0·023) than those with recurrent reflux or paraoesophageal herniation.

Conclusion

Revisional surgery following laparoscopic fundoplication can produce good long-term results, but revision for dysphagia has less satisfactory outcomes.

Detection of lymph node metastases in oesophageal cancer

Background

The importance of lymph node status in oesophageal cancer cannot be disputed. It is therefore surprising that no standardization exists in either terminology or methodology in lymph node analysis.

Methods

All online databases were searched to identify articles published from 1970 onwards. This was supplemented by hand searching references of retrieved articles.

Results and conclusion

Without accurate identification of lymph node metastases, patients cannot be staged properly, nor can best practice for the treatment of oesophageal cancer be determined. This review outlines the problem and proposes recommendations for standardization in terminology and methodology for the detection of lymph node metastases in oesophageal cancer.

Comparison of an amorphous silicon/cesium iodide flat-panel digital chest radiography system with screen/film and computed radiography systems--a contrast-detail phantom study

Flat-panel (FP) based digital radiography systems have recently been introduced as a new and improved digital radiography technology; it is important to evaluate and compare this new technology with currently widely used conventional screen/film (SF) and computed radiography (CR) techniques. In this study, the low-contrast performance of an amorphous silicon/cesium iodide (aSi/Csl)-based flat-panel digital chest radiography system is compared to those of a screen/film and a computed radiography system by measuring their contrast-detail curves. Also studied were the effects of image enhancement in printing the digital images and dependence on kVp and incident exposure. It was found that the FP system demonstrated significantly better low-contrast performance than the SF or CR systems. It was estimated that a dose savings of 70%-90% could be achieved to match the low-contrast performance of the FP images to that of the SF images. This dose saving was also found to increase with the object size. No significant difference was observed in low-contrast performances between the SF and CR systems. The use of clinical enhancement protocols for printing digital images was found to be essential and result in better low-contrast performance. No significant effects were observed for different kVps. From the results of this contrast-detail phantom study, the aSi/CsI-based flat-panel digital chest system should perform better under clinical situations for detection of low-contrast objects such as lung nodules. However, proper processing prior to printing would be essential to realizing this better performance.

Steady-state kinetic characterization of substrates and metal-ion specificities of the full-length and N-terminally truncated recombinant human methionine aminopeptidases (type 2)

The steady-state kinetics of a full-length and truncated form of the type 2 human methionine aminopeptidase (hMetAP2) were analyzed by continuous monitoring of the amide bond cleavage of various peptide substrates and methionyl analogues of 7-amido-4-methylcoumarin (AMC) and p-nitroaniline (pNA), utilizing new fluorescence-based and absorbance-based assay substrates and a novel coupled-enzyme assay method. The most efficient substrates for hMetAP2 appeared to be peptides of three or more amino acids for which the values of k(cat)/K(m) were approximately 5 x 10(5) M(-1) min(-1). It was found that while the nature of the P1' residue of peptide substrates dictates the substrate specificity in the active site of hMetAP2, the P2' residue appears to play a key role in the kinetics of peptidolysis. The catalytic efficiency of dipeptide substrates was found to be at least 250-fold lower than those of the tripeptides. This substantially diminished catalytic efficiency of hMetAP2 observed with the alternative substrates MetAMC and MetpNA is almost entirely due to the reduction in the turnover rate (k(cat)), suggesting that cleavage of the amide bond is at least partially rate-limiting. The 107 N-terminal residues of hMetAP2 were not required for either the peptidolytic activity of the enzyme or its stability. Steady-state kinetic comparison and thermodynamic analyses of an N-terminally truncated form and full-length enzyme yielded essentially identical kinetic behavior and physical properties. Addition of exogenous Co(II) cation was found to significantly activate the full-length hMetAP2, while Zn(II) cation, on the other hand, was unable to activate hMetAP2 under any concentration that was tested.

The therapeutic potential of advances in cysteine protease inhibitor design

Cysteine proteases are attracting increased attention for therapeutic intervention by inhibitors because of an increased recognition of specific processing functions in both mammals and microbes. New advances in inhibitor design have been made for both reversible and irreversible classes. Reversible inhibitors may incorporate a covalent bond formation that can contribute an element of selectivity relative to serine protease inhibition. Ketones of low intrinsic reactivity are especially attractive agents, with potential for chronic therapeutic use. Effectively irreversible inhibition can be achieved with slow or single turnover substrates. This approach eliminates any reactivity toward non-enzyme nucleophiles. Only mechanistically related enzyme targets will be irreversibly blocked in an in vivo setting, thereby resulting in a safer type of inhibitor.

Performance analysis of a new semiorthogonal spline wavelet compression algorithm for tonal medical images

Lossy image compression is thought to be a necessity as radiology moves toward a filmless environment. Compression algorithms based on the discrete cosine transform (DCT) are limited due to the infinite support of the cosine basis function. Wavelets, basis functions that have compact or nearly compact support, are mathematically better suited for decorrelating medical image data. A lossy compression algorithm based on semiorthogonal cubic spline wavelets has been implemented and tested on six different image modalities (magnetic resonance, x-ray computed tomography, single photon emission tomography, digital fluoroscopy, computed radiography, and ultrasound). The fidelity of the reconstructed wavelet images was compared to images compressed with a DCT algorithm for compression ratios of up to 40:1. The wavelet algorithm was found to have generally lower average error metrics and higher peak-signal-to-noise ratios than the DCT algorithm.

Design and synthesis of diaminopyrrolidinone inhibitors of human osteoclast cathepsin K

The structure-based design and synthesis of lactam-constrained azapeptide inhibitors of human cathepsin K are described. Enhanced stability to proteolytic cleavage over acyclic analogues is discussed.

Atypical glandular cells of undetermined significance on cervical smears. A study with cytohistologic correlation

OBJECTIVE

The incidence of endocervical adenocarcinoma has increased steadily over the past two decades. Since the Bethesda System was introduced, the diagnosis of atypical glandular cells of undetermined significance (AGUS) has also risen and now accounts for 0.46-1.83% of all cervical (Pap) smears. The purpose of this study was to evaluate the significance of a diagnosis of AGUS using cytohistologic correlation.

STUDY DESIGN

A retrospective review of archival material from 1993 through 1996 identified 64 patients who had smears diagnosed as AGUS and had a subsequent surgical biopsy. The smears were reviewed and cytologic features analyzed and correlated with the histologic diagnosis.

RESULTS

On biopsy, 3 (5%) of the 64 cases showed endocervical adenocarcinoma in situ (AIS) (1 case with invasive adenocarcinoma also), 14 (22%) had a benign glandular lesion (endocervical polyp, tubal metaplasia, microglandular hyperplasia, reactive changes), 35 (54%) had squamous intraepithelial lesion (SIL) (15 diagnosed on the original smear), and 12 (19%) had no abnormality. Among the cytologic criteria evaluated, feathering (P = .01), palisading (P < .001) and chromatin clearing (P = .002) were shown to have a significant association with the histopathologic diagnosis of AIS/adenocarcinoma. These features were also useful in distinguishing AIS/adenocarcinoma from SIL and benign glandular changes from AIS/adenocarcinoma but not benign/reactive glandular changes from SIL.

CONCLUSION

A diagnosis of AGUS correlated with a clinically significant lesion in the majority of cases. Squamous dysplasia (SIL) was the most common lesion identified. The presence of feathering, nuclear palisading and chromatin clearing increased the likelihood of a histologic diagnosis of AIS/adenocarcinoma.

Structure-based design of non-peptide, carbohydrazide-based cathepsin K inhibitors

Using binding models which were based on the X-ray crystal structure of an amino acid-based active site-spanning inhibitor complexed with cathepsin K, Cbz-leucine mimics have been developed, leading ultimately to the design of a potent cathepsin K inhibitor free of amino acid components. These mimics, which consist of alpha-substituted biphenylacetyl groups in place of Cbz-leucine moieties, effectively mimic all aspects of the Cbz-leucine moieties which are important for inhibitor binding. The predicted directions of binding for the inhibitors were confirmed by mass spectral analysis of their complexes with cathepsin K, which gave results consistent with acylation of the enzyme and loss of the acylhydrazine portion of the inhibitor which binds on the S' side of the active site. The binding models were found to be very predictive of relative inhibitor potency as well as direction of inhibitor binding. These results strengthen the validity of a strategy involving iterative cycles of structure-based design and inhibitor synthesis and evaluation for the discovery of non-peptide inhibitors.

Potent dipeptidylketone inhibitors of the cysteine protease cathepsin K

Cathepsin K (EC 3.4.22.38) is a cysteine protease of the papain superfamily which is selectively expressed within the osteoclast. Several lines of evidence have pointed to the fact that this protease may play an important role in the degradation of the bone matrix. Potent and selective inhibitors of cathepsin K could be important therapeutic agents for the control of excessive bone resorption. Recently a series of peptide aldehydes have been shown to be potent inhibitors of cathepsin K. In an effort to design more selective and metabolically stable inhibitors of cathepsin K, a series of electronically attenuated alkoxymethylketones and thiomethylketones inhibitors have been synthesized. The X-ray co-crystal structure of one of these analogues in complex with cathepsin K shows the inhibitor binding in the primed side of the enzyme active site with a covalent interaction between the active site cysteine 25 and the carbonyl carbon of the inhibitor.

Use of papain as a model for the structure-based design of cathepsin K inhibitors: crystal structures of two papain-inhibitor complexes demonstrate binding to S'-subsites

Papain has been used as a surrogate enzyme in a drug design effort to obtain potent and selective inhibitors of cathepsin K, a new member of the papain superfamily of cysteine proteases that is selectively and highly expressed in osteoclasts and is implicated in bone resorption. Here we report the crystal structures of two papain-inhibitor complexes and the rational design of novel cathepsin K inhibitors. Unlike previously known crystal structures of papain-inhibitor complexes, our papain structures show ligand binding extending deep within the S'-subsites. The two inhibitor complexes, carbobenzyloxyleucinyl-leucinyl-leucinal and carbobenzyloxy-L-leucinyl-L-leucinyl methoxymethyl ketone, were refined to 2.2- and 2.5-A resolution with R-factors of 0.190 and 0. 217, respectively. The S'-subsite interactions with the inhibitors are dominated by an aromatic-aromatic stacking and an oxygen-aromatic ring edge interaction. The knowledge of S'-subsite interactions led to a design strategy for an inhibitor spanning both subsites and yielded a novel, symmetric inhibitor selective for cathepsin K. Simultaneous exploitation of both S- and S'-sites provides a general strategy for the design of cysteine protease inhibitors having high specificity to their target enzymes.

Structure-based design of cathepsin K inhibitors containing a benzyloxy-substituted benzoyl peptidomimetic

Peptidomimetic cathepsin K inhibitors have been designed using binding models which were based on the X-ray crystal structure of an amino acid-based, active site-spanning inhibitor complexed with cathepsin K. These inhibitors, which contain a benzyloxybenzoyl group in place of a Cbz-leucine moiety, maintained good inhibitory potency relative to the amino acid-based inhibitor, and the binding models were found to be very predictive of relative inhibitor potency. The binding mode of one of the inhibitors was confirmed by X-ray crystallography, and the crystallographically determined structure is in close qualitative agreement with the initial binding model. These results strengthen the validity of a strategy involving iterative cycles of structure-based design, inhibitor synthesis and evaluation, and crystallographic structure determination for the discovery of peptidomimetic inhibitors.

Spatial sampling

Sampling in a spatial setting is typically done for the purpose of estimating or predicting a population quantity such as the total of a variable in a study region, to predict a new value at an unobserved site, or to find regions of high values for further study. Spatial covariance and conditional variance patterns have led to the use of designs such as systematic and stratified arrangements to increase precision and cluster or multistage sampling to increase cost effectiveness. In addition, adaptive procedures can be used to take advantage of patterns not discovered prior to the survey. An adaptive sampling design is one in which the procedure for selecting sites or units to include in the sample can depend on values of the variable of interest observed during the survey. For example, in a survey of an unevenly distributed insect species, neighbouring sites may be added to the sample whenever high abundance of the insects is encountered. Examples of adaptive designs include adaptive cluster sampling and adaptive allocation. Issues of design optimality or effectiveness and choice of inference methods with different types of designs will be discussed.

Introduction to wavelet-based compression of medical images

Medical image compression can significantly enhance the performance of picture archiving and communication systems and may be considered an enabling technology for telemedicine. The wavelet transform is a powerful mathematical tool with many unique qualities that are useful for image compression and processing applications. Although wavelet concepts can be traced back to 1910, the mathematics of wavelets have only recently been formalized. By exploiting spatial and spectral information redundancy in images, wavelet-based methods offer significantly better results for compressing medical images than do compression algorithms based on Fourier methods, such as the discrete cosine transform used by the Joint Photographic Experts Group. Furthermore, wavelet-based compression does not suffer from blocking artifacts, and the restored image quality is generally superior at higher compression rates.

Design of potent and selective human cathepsin K inhibitors that span the active site

Potent and selective active-site-spanning inhibitors have been designed for cathepsin K, a cysteine protease unique to osteoclasts. They act by mechanisms that involve tight binding intermediates, potentially on a hydrolytic pathway. X-ray crystallographic, MS, NMR spectroscopic, and kinetic studies of the mechanisms of inhibition indicate that different intermediates or transition states are being represented that are dependent on the conditions of measurement and the specific groups flanking the carbonyl in the inhibitor. The species observed crystallographically are most consistent with tetrahedral intermediates that may be close approximations of those that occur during substrate hydrolysis. Initial kinetic studies suggest the possibility of irreversible and reversible active-site modification. Representative inhibitors have demonstrated antiresorptive activity both in vitro and in vivo and therefore are promising leads for therapeutic agents for the treatment of osteoporosis. Expansion of these inhibitor concepts can be envisioned for the many other cysteine proteases implicated for therapeutic intervention.

Cytologic diagnosis of Ki-1 lymphoma in pleural and peritoneal effusions: a case report

This is a report of a case of Ki-1-positive large-cell anaplastic lymphoma in an 87-year-old man diagnosed on pleural and peritoneal fluids by cytomorphologic and immunohistochemical examination. Papanicolaou-stained smears revealed many single, large neoplastic cells containing one or two nuclei with occasional multinucleated cells having a wreath-like nuclear arrangement. The tumor cells expressed Ki-1 antigen and epithelial membrane antigen. This is the first known report of Ki-1 lymphoma diagnosed initially on cytologic examination of pleural and peritoneal fluids.

Identification of a loop outside the active site cavity of the human immunodeficiency virus proteases which confers inhibitor specificity

We have investigated the inhibitor specificity for the proteases of the human immunodeficiency viruses, types 1 and 2. Using a series of related inhibitors, the P1' side chain was confirmed to play a significant role in determining both the absolute and relative affinity for the enzymes. To further define the residues in the enzymes responsible for the difference in affinity, chimeric proteins were constructed in which domains of the respective proteases were exchanged at the genetic level. The results of these studies demonstrated that inhibitor affinity is conferred by a combination of the active site residues (32, 47, and 82) along with a loop comprised of residues 31 and 33-37, which lies outside of the active site cavity. These results are discussed in terms of existing structural data.

Adaptive sampling in behavioral surveys

Studies of populations such as drug users encounter difficulties because the members of the populations are rare, hidden, or hard to reach. Conventionally designed large-scale surveys detect relatively few members of the populations so that estimates of population characteristics have high uncertainty. Ethnographic studies, on the other hand, reach suitable numbers of individuals only through the use of link-tracing, chain referral, or snowball sampling procedures that often leave the investigators unable to make inferences from their sample to the hidden population as a whole. In adaptive sampling, the procedure for selecting people or other units to be in the sample depends on variables of interest observed during the survey, so the design adapts to the population as encountered. For example, when self-reported drug use is found among members of the sample, sampling effort may be increased in nearby areas. Types of adaptive sampling designs include ordinary sequential sampling, adaptive allocation in stratified sampling, adaptive cluster sampling, and optimal model-based designs. Graph sampling refers to situations with nodes (for example, people) connected by edges (such as social links or geographic proximity). An initial sample of nodes or edges is selected and edges are subsequently followed to bring other nodes into the sample. Graph sampling designs include network sampling, snowball sampling, link-tracing, chain referral, and adaptive cluster sampling. A graph sampling design is adaptive if the decision to include linked nodes depends on variables of interest observed on nodes already in the sample. Adjustment methods for nonsampling errors such as imperfect detection of drug users in the sample apply to adaptive as well as conventional designs.

Proteolytic activity of human osteoclast cathepsin K. Expression, purification, activation, and substrate identification

Human cathepsin K is a recently identified protein with high primary sequence homology to members of the papain cysteine protease superfamily including cathepsins S, L, and B and is selectively expressed in osteoclasts (Drake, F.H., Dodds, R., James I., Connor J., Debouck, C., Richardson, S., Lee, E., Rieman, D., Barthlow, R., Hastings, G., and Gowen, M. (1996) J. Biol., Chem. 271, 12511-12516). To characterize its catalytic properties, cathepsin K has been expressed in baculovirus-infected SF21 cells and the soluble recombinant protein isolated from growth media was purified. Purified protein includes an inhibitory pro-leader sequence common to this family of protease. Conditions for enzyme activation upon removal of the pro-sequence have been identified. Fluorogenic peptides have been identified as substrates for mature cathepsin K. In addition, two protein components of bone matrix, collagen and osteonectin, have been shown to be substrates of the activated protease. Cathepsin K is inhibited by E-64 and leupeptin, but not for by pepstatin, EDTA, phenylmethylsulfonyl fluoride, or phenanthroline, consistent with its classification within the cysteine protease class. Leupeptin has been characterized as a slow binding inhibitor of cathepsin K (kobs/[I] = 273,000 m(-1).s(-1)). Cathepsin K may represent the elusive protease implicated in degradation of protein matrix during bone resorption and represents a novel molecular target in treatment of disease states associated with excessive bone loss such as osteoporosis.

Design and evaluation of small peptides mapping the exposed surface of IL-8

In an effort to determine which regions of IL-8 are involved in interactions with its receptors, eight peptides were designed to correspond to distinct exposed regions of the IL-8 monomer, using the proton NMR-derived structure of the dimer as a basis. The peptides were evaluated singularly, and as equimolar mixtures of two to six peptides, in an IL-8 receptor binding assay and found to have no binding interaction with either alpha or beta IL-8 receptor as single peptides or mixtures of two peptides. In contrast, one of these peptides having the sequence AVLPRSAKEL, which corresponds to the N-terminal 10 amino acid residues of the 77 amino acid form of IL-8, exhibited potent chemotactic activity in human neutrophils. These results indicate that there is no contiguous ligand that can be designed based on the NMR and X-ray determined structure of IL-8 and that there may be multiple receptors responsible for neutrophil activation and chemotaxis.

Rational design, synthesis, and crystallographic analysis of a hydroxyethylene-based HIV-1 protease inhibitor containing a heterocyclic P1'--P2' amide bond isostere

The rational design and synthesis of a highly potent inhibitor of HIV-1 protease have been accomplished. The inhibitor, SB 206343, is based on a model derived from the structure of the MVT-101/HIV-1 protease complex and contains a 4(5)-acylimidazole ring as an isosteric replacement for the P1'--P2' amide bond. It is a competitive inhibitor with an apparent inhibition constant of 0.6 nM at pH 6.0. The three-dimensional structure of SB 206343 bound in the active site of HIV-1 protease has been determined at 2.3 A resolution by X-ray diffraction techniques and refined to a crystallographic discrepancy factor, R (= sigma parallel Fo magnitude of/Fc parallel/sigma magnitude of), of 0.194. The inhibitor is held in the enzyme by a set of hydrophobic and polar interactions. N-3 of the imidazole ring participates in a novel hydrogen-bonding interaction with the bound water molecule, demonstrating the effectiveness of the imidazole ring as an isosteric replacement for the P1'--P2' amide bond in hydroxyethylene-based HIV-1 protease inhibitors. Also present are hydrogen-bonding interactions between N-1 of the imidazole ring and the carbonyl of Gly-127 as well as between the imidazole acyl carbonyl oxygen and the amide nitrogen of Asp-129, exemplifying the peptidomimetic nature of the 4(5)-acylimidazole isostere. All of these interactions are in qualitative agreement with those predicted by the model.

Detectability in conventional and adaptive sampling

In this paper a simple but very general method is given for estimating a population total with any sampling design when objects in sampled units are observed with imperfect detectability--a problem characteristic of many surveys of natural and human populations. In the most general case, the method consists of dividing the value of the variable of interest associated with each detected object by the detection probability for that object and then proceeding to use the estimation method that would ordinarily be used under the design if there were no detectability problems. Examples illustrating the method include simple random sampling, conventional unequal probability sampling, and adaptive cluster sampling.

Paranuclear blue inclusions: an aid in the cytopathologic diagnosis of primary and metastatic pulmonary small-cell carcinoma

Accurate diagnosis of small-cell carcinoma of the lung (SCLC) is clinically important because of the therapeutic implications. SCLC must be distinguished from non-small-cell carcinoma (NSCLC) and lymphoma. Paranuclear blue inclusions (PBIs) were recently described as a feature of metastatic SCLC on air-dried Wright-stained bone marrow aspirate smears. To determine the utility of PBIs in distinguishing SCLC from NSCLC and lymphoma, we evaluated air-dried Diff-Quik-stained smears from 103 fine-needle aspiration (FNA) specimens and 14 touch imprint specimens. PBIs were identified in 24 (89%) of 27 cases of SCLC, in 6 (9%) of 64 non-small-cell carcinomas (P < 0.00001), and in two (8%) of the 26 lymphoma cases (P < 0.00001). No PBIs were seen on any of the alcohol-fixed Papanicolaou or hematoxylin-eosin (H&E) stained smears examined. In conclusion, PBIs appear to be a feature of SCLC on air-dried cytologic material stained with Romanowsky type stains. In the presence of cytologic features of SCLC, the identification of PBIs provides a useful diagnostic feature for differentiating between SCLC and NSCLC carcinomas, and between SCLC and lymphomas in FNA specimens and touch imprints from surgical specimens.

Radiation-induced changes in the breast: a potential diagnostic pitfall on fine-needle aspiration

The authors report a case of fine-needle aspiration (FNA) of a breast mass in a 36-year-old woman with previous history of lumpectomy and therapeutic radiation for breast carcinoma. The changes seen were interpreted as recurrent carcinoma, while subsequent biopsy showed only radiation changes. Radiation-induced changes in breast tissue are a potential diagnostic pitfall. The characteristic cytopathologic changes and their differential diagnosis are discussed.

Cytologic diagnosis of a chordoma without physaliforous cells

Fine-needle aspiration cytology of a presacral chordoma without the classic physaliforous cells is reported. The potential for the misdiagnosis of these lesions when these cells are absent is discussed. The pertinent literature related to this case is reviewed.

Refracture of the patella

Mildly displaced fractures of the patella, with an intact extensor mechanism, are widely treated in a plaster cylinder. This may lead to disuse osteoporosis of the patella and a subsequent refracture, which may be at a different site. A suggested method of splintage is to use a removable back splint for a period of 1-2 weeks.

Cerebral function before and after extra-intracranial carotid bypass

Thirty-eight patients had their cerebral function measured before and after extra-intracranial carotid bypass surgery using the Halstead-Reitan neuropsychology test battery. Two composite indices of cerebral function for each patient showed them to be impaired before operation. There was no improvement in the composite measures after operation to match that previously demonstrated after carotid endarterectomy. This may reflect the greater pre-operative cerebral impairment of the extra-intracranial group.

Prognosis in infantile idiopathic scoliosis

A review was performed of 86 cases of infantile idiopathic scoliosis treated between 1962 and 1979. The single primary curves were classified as resolving, stable, progressive with a low rib--vertebra angle difference (RVAD) and progressive with a high RVAD. Two single primary curves subsequently developed a second curve and 17 were double when first diagnosed. Prognosis was difficult to establish before the age of five years. Only 18 per cent of curves showing progression beyond 50 degrees reached that point before the age of four. Conversely, if a scoliosis of 50 degrees or more was present before the age of four it always progressed. A more favourable outcome was indicated by male sex, a left-sided curve, a low initial curve measurement, an RVAD of less than 20 degrees in the initial radiograph, and the onset of scoliosis in the first year of life.

Gender-deviant boys compared with normal and clinical control boys

The physical movement and social characteristics of effeminate behavior-problem, referred boys (N = 13) were compared with those of normal boys (N = 25) and boys (N = 12) referred for nongender problems. Parent reports, observer ratings, and videotapes were collected in a series of structured tasks. As expected, mothers described gender-problem sons as much more feminine than the other two groups in interests, activities, and mannerisms. Gender-problem sons were also seen as relatively inactive and introverted. Further, they were nonsignificantly lower than the clinical control boys in perceived behavior problems, but both groups had marginally more problems than the normal boys. Gender-problem and clinical control boys both showed more body constriction than normal boys in ratings of a videotaped interview. They also both showed less ideal ball-throw form than normal boys on a set of variables scored with slow-motion video. However, in a set of behaviors directly rated in the various tasks, the gender-problem boys gave a uniquely general impression of uncoordination. The groups did not differ on seven additional variables.