Added Value of Next Generation over Sanger Sequencing in Kenyan Youth with Extensive HIV-1 Drug Resistance

HIV-1 drug resistance testing in children and adolescents in low-resource settings is both important and challenging. New (more sensitive) drug resistance testing technologies may improve clinical care, but evaluation of their added value is limited. We assessed the potential added value of using next-generation sequencing (NGS) over Sanger sequencing for detecting nucleoside reverse transcriptase inhibitor (NRTI) and nonnucleoside reverse transcriptase inhibitor (NNRTI) drug resistance mutations (DRMs). Participants included 132 treatment-experienced Kenyan children and adolescents with diverse HIV-1 subtypes and with already high levels of drug resistance detected by Sanger sequencing. We examined overall and DRM-specific resistance and its predicted impact on antiretroviral therapy and evaluated the discrepancy between Sanger sequencing and six NGS thresholds (1%, 2%, 5%, 10%, 15%, and 20%). Depending on the NGS threshold, agreement between the two technologies was 62% to 88% for any DRM, 83% to 92% for NRTI DRMs, and 73% to 94% for NNRTI DRMs, with more DRMs detected at low NGS thresholds. NGS identified 96% to 100% of DRMs detected by Sanger sequencing, while Sanger identified 83% to 99% of DRMs detected by NGS. Higher discrepancy between technologies was associated with higher DRM prevalence. Even in this resistance-saturated cohort, 12% of participants had higher, potentially clinically relevant predicted resistance detected only by NGS. These findings, in a young, vulnerable Kenyan population with diverse HIV-1 subtypes and already high resistance levels, suggest potential benefits of more sensitive NGS over existing technology. Good agreement between technologies at high NGS thresholds supports their interchangeable use; however, the significance of DRMs identified at lower thresholds to patient care should be explored further. IMPORTANCE HIV-1 drug resistance in children and adolescents remains a significant problem in countries facing the highest burden of the HIV epidemic. Surveillance of HIV-1 drug resistance in children and adolescents is an important public health strategy, particularly in resource-limited settings, and yet, it is limited due mostly to cost and infrastructure constraints. Whether newer and more sensitive next-generation sequencing (NGS) adds substantial value beyond traditional Sanger sequencing in detecting HIV-1 drug resistance in real life settings remains an open and debatable question. In this paper, we attempt to address this issue by performing a comprehensive comparison of drug resistance identified by Sanger sequencing and six NGS thresholds. We conducted this study in a well-characterized, vulnerable cohort of children and adolescents living with diverse HIV-1 subtypes in Kenya and, importantly, failing antiretroviral therapy (ART) with already extensive drug resistance. Our findings suggest a potential added value of NGS over Sanger even in this unique cohort.

What are the best endpoints for Eczema Area and Severity Index and Scoring Atopic Dermatitis in clinical practice? A prospective observational study

BACKGROUND

Multiple strategies have been used to evaluate the minimal important change (MIC) of the Eczema Area and Severity Index (EASI) and Scoring Atopic Dermatitis (SCORAD). The meaningfulness of these MICs is not well established across all severities of atopic dermatitis (AD).

OBJECTIVES

To determine the MIC of percentage and absolute improvement of EASI and SCORAD scores in adults and children with AD.

METHODS

We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist (n = 826). An anchor-based approach was used to determine thresholds for the percentage and absolute MICs of EASI, SCORAD and objective SCORAD (O-SCORAD) at follow-up from baseline.

RESULTS

One-grade improvements of Physician's Global Assessment (PGA) and validated Investigator Global Assessment scale for AD (vIGA-AD) were associated with 50%, 35% and 35% decreases of EASI, SCORAD and O-SCORAD, respectively. The thresholds for percentage MIC of EASI (Kruskal-Wallis test, P = 0·61), SCORAD (P = 0·07) and O-SCORAD (P = 0·09) were similar across baseline AD severities. One-grade improvements of PGA and vIGA-AD were associated with 14·0- and 14·9-point decreases of EASI, 19·9- and 14·9-point decreases of SCORAD, and 15·5- and 17·4-point decreases of O-SCORAD. The thresholds for the absolute MIC of EASI (P < 0·001), SCORAD (P < 0·001) and O-SCORAD (P < 0·001) significantly differed by baseline AD severity. Percentage and absolute MICs for EASI and SCORAD were associated with improvements of AD symptoms and quality of life.

CONCLUSIONS

EASI 50, SCORAD 35 and O-SCORAD 35 were meaningful percentage MICs regardless of baseline AD severity. The absolute MICs for EASI, SCORAD and O-SCORAD varied by baseline AD severity.

Measurement properties of the product of investigator's global assessment and body surface area in children and adults with atopic dermatitis

BACKGROUND

Multiple clinician-reported outcome measures exist for atopic dermatitis (AD) severity. However, there is no gold standard for use in clinical practice.

OBJECTIVES

To determine the measurement properties of the product of validated Investigator's Global Assessment for AD (vIGA) and body surface area (BSA) overall or divided into six categories (cBSA: 0%/0.1, <10%/10, <30%/30, <50%/50, <70%/70 and <90%/90-100%) and compare with other clinician-reported and patient-reported outcomes in adults and children with AD.

METHODS

We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist (n = 653).

RESULTS

vIGA*BSA and vIGA*cBSA had good convergent validity with BSA (Spearman's ρ = 0.97 and 0.93), eczema area and severity index (ρ = 0.94 and 0.92), and objective SCORAD (ρ = 0.88 and 0.89); and weak-to-good convergent validity with Numeric Rating Scale average itch (ρ = 0.22 and 0.22) and worst itch (ρ = 0.27 and 0.28), Patient-Oriented Eczema Measure (ρ = 0.44 and 0.43), Dermatology Life Quality Index (ρ = 0.48 and 0.49), ItchyQOL (ρ = 0.45 and 0.46), PROMIS Sleep Disturbance (ρ = 0.46 and 0.37) and sleep-related impairment (ρ = 0.31 and 0.31) in adults and/or children; very good discriminant validity for physician-reported global AD severity; good responsiveness to change of severity of AD and itch; and good reliability (intraclass correlation coefficient [95% confidence interval]: 0.72 [0.60-0.81] and 0.74 [0.62-0.82]) with no floor or ceiling effects. Thresholds for interpretability bands and clinically important difference were established.

CONCLUSIONS

vIGA*BSA and vIGA*cBSA scores showed good convergent and discriminant validity, reliability, responsiveness and interpretability in adults and children with AD, and were feasible for use in clinical practice. vIGA*BSA and vIGA*cBSA had slightly lower convergent validity than EASI or objective SCORAD, but might be more efficient to collect and score.

Measurement properties of the Rajka-Langeland severity score in children and adults with atopic dermatitis

BACKGROUND

Multiple atopic dermatitis (AD) severity scales exist, with no gold standard for use in clinical practice.

OBJECTIVES

To determine the measurement properties of the Rajka-Langeland score and compare it with other clinician-reported outcomes in adults and children with AD.

METHODS

We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist (n = 427).

RESULTS

Rajka-Langeland had good concurrent validity with the Eczema Area and Severity Index (Spearman rho = 0·63), SCORing AD (SCORAD) (rho = 0·61), objective-SCORAD (rho = 0·52) and body surface area (rho = 0·51); good convergent validity with the numeric rating scale average-itch (rho = 0·60) and worst-itch (rho = 0·59), Patient-Oriented Eczema Measure (rho = 0·57), Dermatology Life Quality Index (rho = 0·53), Patient-Reported Outcomes Measurement Information System Itch Questionnaire (rho = 0·35-0·55) in adults and/or children; fair discriminant validity for patient- and physician-reported global AD severity; good responsiveness to change of severity of AD and itch; good reliability; internal consistency; with no floor or ceiling effects. Interpretability bands (3, clear/almost clear; 4-5, mild; 6-7, moderate; 8-9, severe) and minimal clinically important difference (1 point) were established.

CONCLUSIONS

The Rajka-Langeland score showed good construct validity, reliability, internal consistency and responsiveness in adults and children with AD.

Measurement properties of three assessments of burden used in atopic dermatitis in adults

BACKGROUND

Standardized quality-of-life (QoL) assessments can provide important and clinically relevant information. There is currently a lack of standardization in QoL assessments used in atopic dermatitis (AD).

OBJECTIVES

To determine the content validity, construct validity, internal consistency, differential reporting, responsiveness, floor or ceiling effects and feasibility of the Dermatology Life Quality Index (DLQI), Itchy Quality of Life (ItchyQoL) and 5-dimensions (5-D) itch scales for assessing burden of AD in adults and to compare their performance.

METHODS

Self-administered questionnaires and skin examination were performed in 340 adults with AD in a dermatology practice setting.

RESULTS

DLQI, ItchyQoL and 5-D all had good content validity. DLQI, mean ItchyQoL and 5-D itch all had strong correlations with frequency of AD symptoms (Patient-Oriented Eczema Measure) and intensity of itch (numerical rating scale for itch), and moderate correlations with AD severity (Eczema Area and Severity Index and Scoring Atopic Dermatitis) (Spearman correlations, P < 0·001 for all). DLQI and 5-D itch showed good internal consistency (Cronbach's alpha = 0·89 and 0·84), although ItchyQoL appeared to have several redundant items (alpha = 0·96). Uniform and nonuniform differential item functioning by age, sex and/or race/ethnicity was found for multiple items in DLQI, ItchyQoL and 5-D itch. DLQI, ItchyQoL and 5-D itch scores all demonstrated responsiveness, although ItchyQoL demonstrated the greatest responsiveness. There were no floor or ceiling effects for total scores. The median times for completion of DLQI, ItchyQoL and 5-D itch were 2 min.

CONCLUSIONS

The DLQI, ItchyQoL and 5-D itch scales all showed good content and construct validity, and responsiveness in the assessment of AD in adults, and were feasible for use in clinical trials and practice.

Severity strata for five patient-reported outcomes in adults with atopic dermatitis

BACKGROUND

Several patient-reported outcomes have been used to assess the burden of atopic dermatitis (AD). Some are disease specific, such as the Patient-Oriented Eczema Measure (POEM), while others pertain to itch, for example the numerical rating scale (NRS)-itch, ItchyQoL and 5-D itch, or dermatological disease in general, for example the Dermatology Life Quality Index (DLQI). Development of severity strata is essential for proper interpretability of these assessments.

OBJECTIVES

To confirm previously developed strata for POEM, DLQI and raw ItchyQoL, and develop strata for the NRS-itch, mean ItchyQoL and 5-D itch scale for use in adults with AD.

METHODS

Self-administered questionnaires were completed by 210 adults with AD in a dermatology practice setting. Strata were selected using an anchoring approach based on patient-reported disease severity.

RESULTS

We confirmed the existing strata for POEM (mild 0-7, moderate 8-16, severe 17-28; κ = 0·440), DLQI (mild 0-5, moderate 6-10, severe 11-30; κ = 0·398) and NRS-itch (mild 0-3, moderate 4-6, severe 7-10; κ = 0·499). However, the preferred band for raw ItchyQoL was mild 22-58, moderate 59-74 and severe 75-110 (κ = 0·379) and for mean ItchyQoL, mild 1-2·9, moderate 3·0-3·9, severe 4·0-5·0 (κ = 0·374). The preferred band for 5-D itch scale was mild 0-11, moderate 12-17 and severe 18-25 (κ = 0·331).

CONCLUSIONS

Existing strata for POEM and DLQI performed well in adult AD. Previously reported strata for visual analogue scale-itch performed best for NRS-itch. We identified banding for the raw ItchyQoL for our AD population that varies slightly from the banding published for a more heterogeneous population. Finally, we proposed strata for mean ItchyQoL and 5-D itch scale in adult AD.

Validation of patient-reported global severity of atopic dermatitis in adults

BACKGROUND

Atopic dermatitis (AD) is associated with a heterogeneous presentation and clinical course. There is a lack of simple and validated severity assessments that are feasible for clinical practice and epidemiological research.

OBJECTIVES

We sought to validate patient-reported global AD severity in adults.

METHODS

We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist (n = 265).

RESULTS

At baseline and follow-up, patient-reported global AD severity significantly correlated with oSCORAD (Spearman ρ = 0.56 and 0.49), SCORAD (0.64 and 0.56), EASI (0.56 and 0.50), BSA (0.52 and 0.45), NRS-itch (0.60 and 0.53), POEM (0.50 and 0.48), and DLQI (0.50 and 0.49) (P < .0001 for all). Patient-reported moderate and severe AD vs mild AD were associated with significantly higher oSCORAD, SCORAD, EASI, BSA, NRS-itch, POEM, and DLQI (P < .0001 for all). There was moderate concordance between patient-reported AD severity (mild, moderate, and severe) and previously developed severity strata for oSCORAD (κ = 0.39), SCORAD (κ = 0.47), EASI (κ = 0.37), NRS-itch (κ = 0.49), POEM (κ = 0.37), and DLQI (κ = 0.40). Among patients with severe disease at baseline, those who reported mild or moderate disease on follow-up had significantly greater absolute reductions of oSCORAD (-23.4/-9.7/-1.8), SCORAD (-33.0/-13.2/-2.3), EASI (-17.1/-9.8/-3.2), BSA (-46%/-15%/-4%), NRS-itch (-5/-2/0), POEM (-5/-2/0), and DLQI (-8/-6/-1) than those who continued to report severe disease (Kruskal-Wallis, P ≤ .0003 for all).

CONCLUSIONS

Patient-reported AD severity appears to be sufficiently valid for assessing AD severity in the clinical and epidemiological setting.

Atopic dermatitis, atopic eczema, or eczema? A systematic review, meta-analysis, and recommendation for uniform use of 'atopic dermatitis'

BACKGROUND

The lack of standardized nomenclature for atopic dermatitis (AD) creates unnecessary confusion for patients, healthcare providers, and researchers. It also negatively impacts accurate communication of research in the scientific literature. We sought to determine the most commonly used terms for AD.

METHODS

A systematic review of the MEDLINE, EMBASE, and LILACS (1945-2016) for the terms AD, atopic eczema (AE), and multiple other eczematous disorders.

RESULTS

In MEDLINE, 33 060 were identified, of which 21 299 (64.4%) publications used the term 'AD', 15 510 (46.9%) 'eczema', and only 2471 (7.5%) AE. Most of these publications used the term AD (82.0%) or eczema (70.8%) without additional nomenclature; only 1.2% used AE alone. Few publications used the terminology 'childhood eczema', 'flexural eczema', 'infantile eczema', 'atopic neurodermatitis', or 'Besnier's prurigo'. AD was rarely used until the late 1970s, after which it became the most commonly used of the three terms and continuously increased until 2015. Atopic eczema decreased between 2008 and 2015. Atopic dermatitis was the most commonly used term in studies across almost all publication types, languages, and journals.

CONCLUSION

Atopic dermatitis is the most commonly used term and appears to be increasing in popularity. Given that eczema is a nonspecific term that describes the morphological appearance of several forms of dermatitis, we strongly suggest the use of a more specific term, AD, in publications, healthcare clinician training, and patient education. Support from researchers, reviewers, and editors is key to success.

Bayesian network analysis of resistance pathways against HIV-1 protease inhibitors

Interpretation of Human Immunodeficiency Virus 1 (HIV-1) genotypic drug resistance is still a major challenge in the follow-up of antiviral therapy in infected patients. Because of the high degree of HIV-1 natural variation, complex interactions and stochastic behaviour of evolution, the role of resistance mutations is in many cases not well understood. Using Bayesian network learning of HIV-1 sequence data from diverse subtypes (A, B, C, F and G), we could determine the specific role of many resistance mutations against the protease inhibitors (PIs) nelfinavir (NFV), indinavir (IDV), and saquinavir (SQV). Such networks visualize relationships between treatment, selection of resistance mutations and presence of polymorphisms in a graphical way. The analysis identified 30N, 88S, and 90M for nelfinavir, 90M for saquinavir, and 82A/T and 46I/L for indinavir as most probable major resistance mutations. Moreover we found striking similarities for the role of many mutations against all of these drugs. For example, for all three inhibitors, we found that the novel mutation 89I was minor and associated with mutations at positions 90 and 71. Bayesian network learning provides an autonomous method to gain insight in the role of resistance mutations and the influence of HIV-1 natural variation. We successfully applied the method to three protease inhibitors. The analysis shows differences with current knowledge especially concerning resistance development in several non-B subtypes.

Analysis of HIV-1 pol sequences using Bayesian Networks: implications for drug resistance

Human Immunodeficiency Virus-1 (HIV-1) antiviral resistance is a major cause of antiviral therapy failure and compromises future treatment options. As a consequence, resistance testing is the standard of care. Because of the high degree of HIV-1 natural variation and complex interactions, the role of resistance mutations is in many cases insufficiently understood. We applied a probabilistic model, Bayesian networks, to analyze direct influences between protein residues and exposure to treatment in clinical HIV-1 protease sequences from diverse subtypes. We can determine the specific role of many resistance mutations against the protease inhibitor nelfinavir, and determine relationships between resistance mutations and polymorphisms. We can show for example that in addition to the well-known major mutations 90M and 30N for nelfinavir resistance, 88S should not be treated as 88D but instead considered as a major mutation and explain the subtype-dependent prevalence of the 30N resistance pathway.

Fatal liver infarction after transjugular intrahepatic portosystemic shunt procedure

Hepatic infarction is a rare disease. We describe here a cirrhotic patient with end-stage renal failure and recurrent tense ascites with fatal hepatic infarction after transjugular intrahepatic portosystemic shunt (TIPS) procedure. Abdominal ultrasound, radionuclide liver scan, abdominal computed tomography scan, and finally liver biopsy established the diagnosis. The mechanism causing the infarct is not clear. However, as the infarct appeared after the patient had an episode of shock and disseminated intravascular coagulation, it could well be that the concomitant hepatic arterial insufficiency contributed to the infarct. Physicians should be aware of this possible catastrophic complication.

Ascending aortic pseudoaneurysm following coronary bypass in a hemodialysis patient with fever of unknown origin

A unique patient who developed pseudoaneurysm of the ascending aorta after coronary artery bypass grafting is presented. This case is peculiar due to the presenting symptom being fever of unknown origin. It is the first description of a patient on hemodialysis, who developed ascending aortic pseudoaneurysm.

Trans-tubular potassium gradient in patients with drug-induced hyperkalemia

BACKGROUND

Trans-tubular potassium gradient (TTKG) is considered to reflect mainly aldosterone bioactivity with regard to its kaliuretic response. We determined both TTKG and aldosterone serum concentrations in patients with severe drug-induced hyperkalemia (DIH).

METHODS

Ten hyperkalemic patients with serum potassium of more than 5.5 mEq/l, and serum creatinine of less than 2.5 mg/dl (221 micromol/l) were studied prospectively. Two control groups of 10 patients each were used. Control 1 group with normal renal function, and control 2 group with normokalemia and renal failure of the same magnitude as that of the hyperkalemic patients. Serum osmolarity, electrolytes, creatinine, aldosterone and urine electrolytes and osmolarity were measured and TTKG calculated.

RESULTS

DIH patients had lower TTKG values than control 1 patients (2.58 +/- 0.36 vs. 6.68 +/- 0.55, p < 0.001), and also lower than that of the control 2 patients (2.58 +/- 0.36 vs. 5.51 +/- 0.87, p < 0.01). Serum aldosterone concentration in the DIH group was higher than that of the control 1 group [24.30 +/- 5.0 vs. 7.4 +/- 2.1 pg/ml (674 +/- 139 vs. 205 +/- 58 pmol/l), p < 0.006] but not different from that of the control 2 group [24.3 +/- 5.0 vs. 15.3 +/- 3.8 pg/ml (674 +/- 139 vs. 424 +/- 106 pmol/l), respectively, p = 0.18]. Although there was some overlap in TTKG between DIH and control groups, 6 of 10 DIH patients had TTKG of less than 2.5, while none of the control patients had such a low value.

CONCLUSION

DIH is characterized by lower TTKG values than those observed in patients with normal or mild-to-moderate renal failure. Other factors in addition to aldosterone seem to be involved.

Human Immunodeficiency Virus Reverse Transcriptase and Protease Sequence Database: an expanded data model integrating natural language text and sequence analysis programs

The HIV Reverse Transcriptase and Protease Sequence Database is an on-line relational database that catalogs evolutionary and drug-related sequence variation in the human immunodeficiency virus (HIV) reverse transcriptase (RT) and protease enzymes, the molecular targets of anti-HIV therapy (http://hivdb.stanford.edu). The database contains a compilation of nearly all published HIV RT and protease sequences, including submissions from International Collaboration databases and sequences published in journal articles. Sequences are linked to data about the source of the sequence sample and the antiretroviral drug treatment history of the individual from whom the isolate was obtained. During the past year 3500 sequences have been added and the data model has been expanded to include drug susceptibility data on sequenced isolates. Database content has also been integrated with didactic text and the output of two sequence analysis programs.

Kaposi's sarcoma after lung transplantation in a Sephardic Jewish woman

One of the four types of Kaposi's sarcoma (KS), KS after organ transplantation under immunosuppression, is a well-known entity and has been abundantly described in renal, heart and liver recipients. We report the second case of cutaneous KS after lung transplantation, under regular immunosuppression, in a Sephardic Jewish woman. This case, when added to the other 10 cases of posttransplantation KS reported from Israel, all being Sephardic Jews, indicates that in Israel, Sephardic Jews are at higher risk than Ashkenazi Jews to develop posttransplantation KS. This observation should be added to the well-known increased risk of Ashkenazi Jews to develop classic KS. Moreover, in Israel Ashkenazi Jews develop classic KS at higher rates than Sephardic Jews. This apparent discrepancy in the ethnic distribution between Sephardic and Ashkenazi Jews in classic versus posttransplantation KS may shed light on the pathogenesis of KS in general.

Acquired hemophilia masked by warfarin therapy

People without hemophilia but with autoantibodies specifically directed against the procoagulant activity of factor VIII are known to have acquired hemophilia. The bleeding diathesis in these patients is often severe and life-threatening. The definite laboratory diagnosis of this disorder includes demonstration of low factor VIII levels in plasma with a high titer of factor VIII inhibitors, but the initial suspicion for its presence should rise in view of a prolonged partial thromboblastin time (PTT) and a normal prothrombin time associated with an acquired bleeding disorder. Oral anticoagulant treatment is known to prolong PTT as well, and the merger of these 2 situations may cause delayed diagnosis of acquired hemophilia with devastating consequences. We describe here the first reported case of acquired hemophilia diagnosed in a patient treated with warfarin. In such patients prolonged PTT may be ascribed to warfarin therapy rather than to acquired hemophilia, thus causing a dangerous delay in diagnosis.

[High alkaline phosphatase in subacute thyroiditis]

Subacute thyroiditis may be hard to diagnose, therefore patients are sometimes misdiagnosed and subjected to unnecessary work-up. We report a 37-year-old man with subacute thyroiditis and a high concentration of serum alkaline phosphatase. After aspirin treatment there was clinical improvement and decrease in rapid ESR, and in high serum thyroxin and alkaline phosphatase. The increased alkaline phosphatase, seen in as many as 50% of patients, is of hepatic origin, and is not caused by high serum thyroxin. Awareness of this relationship may help in diagnosis and may prevent unnecessary diagnostic procedures, which may be invasive.

Distribution of the CCR5 gene 32-base pair deletion in Israeli ethnic groups

The discovery of inhibition of HIV-1 by selected chemokines and their receptors instills hope in AIDS researchers, especially because a 32-bp deletion in the chemokine receptor CCR5 (delta32-CCR5) provides resistance to HIV infection. A recent report found that the highest delta32-CCR5 frequency is among Ashkenazi Jews (20.93%). In the present study, we have determined by PCR the allelic frequency of delta32-CCR5 in 520 individuals representing a spectrum of ethnic groups living in Israel. The samples were obtained from the Israeli National Laboratory of Genetic Diversity. Our results showed that Ashkenazi Jews, as to be expected, have the highest frequency (10.19%), yet not significantly higher than that which has been reported for whites of European decent. Other ethnic groups, North African Jews, non-Jews, Middle Eastern Jews, and Ethiopian Jews, gave allelic frequencies of 2.08, 1.35, 1.15, and 0, respectively. Thus, the delta32-CCR5 mutation is found in Jews with the same allelic frequency as that found for residents of their countries of origin. Therefore, it appears that the delta32-CCR5 allele has been introduced into Jewish communities world wide through intermarriage and genetic drift.

Automated high resolution optical mapping using arrayed, fluid-fixed DNA molecules

New mapping approaches construct ordered restriction maps from fluorescence microscope images of individual, endonuclease-digested DNA molecules. In optical mapping, molecules are elongated and fixed onto derivatized glass surfaces, preserving biochemical accessibility and fragment order after enzymatic digestion. Measurements of relative fluorescence intensity and apparent length determine the sizes of restriction fragments, enabling ordered map construction without electrophoretic analysis. The optical mapping system reported here is based on our physical characterization of an effect using fluid flows developed within tiny, evaporating droplets to elongate and fix DNA molecules onto derivatized surfaces. Such evaporation-driven molecular fixation produces well elongated molecules accessible to restriction endonucleases, and notably, DNA polymerase I. We then developed the robotic means to grid DNA spots in well defined arrays that are digested and analyzed in parallel. To effectively harness this effect for high-throughput genome mapping, we developed: (i) machine vision and automatic image acquisition techniques to work with fixed, digested molecules within gridded samples, and (ii) Bayesian inference approaches that are used to analyze machine vision data, automatically producing high-resolution restriction maps from images of individual DNA molecules. The aggregate significance of this work is the development of an integrated system for mapping small insert clones allowing biochemical data obtained from engineered ensembles of individual molecules to be automatically accumulated and analyzed for map construction. These approaches are sufficiently general for varied biochemical analyses of individual molecules using statistically meaningful population sizes.

Prevalence of a CCR5 gene 32-bp deletion in an Israeli cohort of HIV-1-infected and uninfected hemophilia patients

OBJECTIVE

The recently discovered connection of chemokines and their receptors to HIV pathogenesis, and the description of the 32-bp deletion in the CCR5 gene (delta 32 CCR5), led to heightened excitement and numerous reports regarding their role in HIV transmission and disease progression. The populations in most of these reports, except for one, consisted of homosexual men. Our objective was to investigate the significance of delta 32 CCR5 in hemophilia patients in Israel.

STUDY DESIGN/METHODS

We have determined by polymerase chain reaction (PCR) the prevalence of delta 32 CCR5 in 34 HIV-seropositive Israeli patients with hemophilia A and compared them with a control group of 42 HIV-seronegative hemophilia patients.

RESULTS

Thirteen heterozygotes were identified among the 76 hemophilia patients tested (allelic frequency, 8.5%), 5 (14.7%) among the HIV-seropositive patients, and 8 (19%) among the noninfected.

CONCLUSIONS

No protective advantage to delta 32 CCR5 heterozygosity was seen as far as infection with HIV is concerned. However, a trend of a slower progression to AIDS in delta 32 CCR5 heterozygotes compared with wild-type homozygotes may be apparent, although no absolute correlation could be made.

Orthopaedic long term aspects of bladder exstrophy

This study evaluates long term orthopaedic aspects of children with bladder exstrophy who were operated on using different techniques and at different ages. Data were accumulated from 20 patients with an age range of 2 to 29 years (average, 13 years). Fourteen patients underwent pelvic osteotomy. Interviews and physical examinations confirmed that, in the long term, children with classical bladder exstrophy do not have significant orthopaedic problems or disability, whether or not they underwent pelvic osteotomy. Radiographic imaging showed normal hip joint configuration with marked pubic diastasis. There were no clinical problems associated with the diastasis. Pelvic computed tomography studies in 7 patients showed marked remodeling of the femora and acetabula. Radiographs of the spine showed a curve in 7 (47%) of the patients, but in only 3 cases was the curve larger than 10 degrees. Pelvic osteotomy is indicated during surgical correction of bladder exstrophy to facilitate closure of the abdominal wall to prevent postoperative wound dehiscence and possibly achieve better urinary control in older age. However, there is no clear indication for pelvic osteotomy from an orthopaedic point of view.

Adults' knowledge about the use of child restraint devices

BACKGROUND

Injuries are the number one cause of morbidity and mortality among children age 14 and younger in the United States, and motor vehicle crashes account for most of these injuries. Although child restraint devices (CRDs) have been shown to protect children involved in motor vehicle crashes, only minimal decreases in mortality and morbidity have occurred since their introduction. This study evaluated the accuracy and sources of adult knowledge about CRDs.

METHODS

A self-administered questionnaire was completed by patients at a community-based family practice clinic to obtain demographic information, assess knowledge of recommendations for CRD use, and identify sources of this knowledge.

RESULTS

Of the 368 participants, 36% were men, 52% were women, and 12% did not indicate gender. The frequencies of correct responses on positioning infants younger than nine months of age and weighing less than 20 lbs in a CRD were: upright, 47%; rear middle-seat location, 22%; and rear facing, 54%. For toddlers older than nine months who weighed more than 20 lbs, the frequencies of correct responses on positioning were: using a booster seat plus a seat belt, 71%; rear-middle location, 17%; and front facing, 66%. In addition, only 42% of the respondents correctly identified the booster seat as not crash-test certified, and 44% indicated that a CRD should not be reused after an accident. The majority of respondents indicated that the year of manufacture was important and that loose objects in the car were not safe. TV/radio (51%), newspaper/magazine (41%), and relatives (31%) were the most common sources of information about CRD use.

CONCLUSION

Our findings suggest that a lack of knowledge about CRD use among adults contributes to improper use of these devices. This may explain the minimal effect CRD use has had on reducing morbidity and mortality of children from motor vehicle crashes.

[Monoclonal antibodies and uveal melanomas]

The authors, who have succeeded since 1976 in cultivating cells of ocular melanoma in continuous lines report the different stages for producing specific monoclonal antibodies. They particularly insist on the demonstration, through radioimmunoassay, of the specificity of marked monoclonal antibodies, on the immunohistochemical study and on biodistribution. From these data, an immunotherapy protocol has been perfected and starts being applied to human beings.

Analysis of rat natural killer cytotoxic factor (NKCF) produced by rat NK cell lines and the production of a murine monoclonal antibody that neutralizes NKCF

Natural killer cytotoxic factor (NKCF) is produced as a result of the interaction of murine, rat, or human natural killer (NK) cells with NK-susceptible targets. This factor has been linked to the target cell lysis mediated by the NK effector cell. In the present results, culture supernatants from rat large granular lymphocyte (LGL) tumors exhibited NKCF activity which lysed the susceptible targets, MBL-2 and YAC-1. NKCF production from these rat tumor lines was spontaneous and was not significantly increased by co-incubation of the LGL tumors with target cells, target cell membranes, or by preincubation of the LGL tumor cells with interferon or interleukin 2. In addition to NKCF activity, the supernatants lysed L929, indicating the presence of tumor necrosis factor (TNF) in these preparations. The presence of this latter cytokine was verified using specific antibodies to recombinant murine TNF which neutralized the L929 activity while not affecting the NKCF activity against MBL-2 or YAC-1. Mouse monoclonal antibodies (mAb) A0287, A0462, and A0316) which significantly inhibit the NKCF cytolytic activity of these LGL-derived supernatants were also produced. These antibodies were shown to cross-react with human NKCF in a manner similar to that seen in the rat. Interestingly these same mAb demonstrated no inhibition of L929 cytotoxicity from either LGL-derived supernatants or by recombinant murine or human TNF. To examine further the specificity of these antibodies, they were chemically linked to Sepharose 4B and found to remove a significant proportion of the NKCF cytolytic activity from LGL supernatants, while not affecting the TNF reactivities in these preparations. In addition, these antibodies demonstrated significant inhibition of cell-mediated cytotoxicity by rat LGL against YAC-1 target cells. Biochemical analysis of labeled NKCF-containing supernatants indicated the major protein recognized by these anti-NKCF mAb to be approximately 12,000 m.w. The use of these mAb against NKCF should be very useful in further purification and biochemical characterization of NKCF and in studying its role in a variety of cell-mediated cytotoxicity assays.

Analysis of rat natural killer cytotoxic factor (NKCF) produced by rat NK cell lines and the production of a murine monoclonal antibody that neutralizes NKCF

Natural killer cytotoxic factor (NKCF) is produced as a result of the interaction of murine, rat, or human natural killer (NK) cells with NK-susceptible targets. This factor has been linked to the target cell lysis mediated by the NK effector cell. In the present results, culture supernatants from rat large granular lymphocyte (LGL) tumors exhibited NKCF activity which lysed the susceptible targets, MBL-2 and YAC-1. NKCF production from these rat tumor lines was spontaneous and was not significantly increased by co-incubation of the LGL tumors with target cells, target cell membranes, or by preincubation of the LGL tumor cells with interferon or interleukin 2. In addition to NKCF activity, the supernatants lysed L929, indicating the presence of tumor necrosis factor (TNF) in these preparations. The presence of this latter cytokine was verified using specific antibodies to recombinant murine TNF which neutralized the L929 activity while not affecting the NKCF activity against MBL-2 or YAC-1. Mouse monoclonal antibodies (mAb) A0287, A0462, and A0316) which significantly inhibit the NKCF cytolytic activity of these LGL-derived supernatants were also produced. These antibodies were shown to cross-react with human NKCF in a manner similar to that seen in the rat. Interestingly these same mAb demonstrated no inhibition of L929 cytotoxicity from either LGL-derived supernatants or by recombinant murine or human TNF. To examine further the specificity of these antibodies, they were chemically linked to Sepharose 4B and found to remove a significant proportion of the NKCF cytolytic activity from LGL supernatants, while not affecting the TNF reactivities in these preparations. In addition, these antibodies demonstrated significant inhibition of cell-mediated cytotoxicity by rat LGL against YAC-1 target cells. Biochemical analysis of labeled NKCF-containing supernatants indicated the major protein recognized by these anti-NKCF mAb to be approximately 12,000 m.w. The use of these mAb against NKCF should be very useful in further purification and biochemical characterization of NKCF and in studying its role in a variety of cell-mediated cytotoxicity assays.

Studies of the normal human placental syncytiotrophoblast membrane: a combined immunological and physiochemical approach

In view of the importance of the syncytiotrophoblast in the immunobiology of human pregnancy, the composition of this interface between fetus and mother was further studied by a combination of physicochemical and immunological approaches. Trophoblast membranes were solubilized using three classes of detergents: zwitterionic (sulfobetaine14), non-ionic (Triton X-100), and anionic (deoxycholate). Quantitative studies of protein released demonstrated the importance of dispersion of membranes into detergent, and optimum solubilization was then obtained at detergent:protein ratios of 1.3:1 for sulfobetaine, 2.5:1 for Triton X-100, and 4.4:1 for deoxycholate. Analysis of chaotrope-treated detergent-solubilized membrane components was performed by preparative isoelectric focusing followed by combined physiocochemical and immunological methods. The results revealed three major proteins which were identified as placental alkaline phosphatase, albumin, and transferrin. Certain additional low molecular weight proteins were also evident; one of these components displayed physicochemical properties similar to those of actin, but none appeared to be recognized by conventional heteroantisera raised to trophoblast membrane. These findings and the results of further immunological analysis by affinity chromatography are consistent with the concept that human trophoblast may express limited immunogenicity due in part to the presence of large amounts of absorbed maternal serum components and limited expression of fetal proteins.

Molecular heterogeneity and shedding of a high-molecular-mass melanoma-associated antigen identified with monoclonal antibodies

This review briefly discusses some recent developments in the use of monoclonal antibodies to study antigens of high molecular mass associated with melanomas, including information on their molecular profile, their heterogeneity, and the effect of interferon on their shedding by melanoma cells.