A local likelihood proportional hazards model for interval censored data.

We discuss the use of local likelihood methods to fit proportional hazards regression models to right and interval censored data. The assumed model allows for an arbitrary, smoothed baseline hazard on which a vector of covariates operates in a proportional manner, and thus produces an interpretable baseline hazard function along with estimates of global covariate effects. For estimation, we extend the modified EM algorithm suggested by Betensky, Lindsey, Ryan and Wand. We illustrate the method with data on times to deterioration of breast cosmeses and HIV-1 infection rates among haemophiliacs.     

The natural history of carpal tunnel syndrome in lactation.

In a retrospective postal study of 27 women who have developed carpal tunnel syndrome (CTS) in the puerperium, the condition was found to affect predominantly elderly primiparous women (mean age 31.5 years). The condition was associated with breastfeeding in 24 women. The three who did not breastfeed had less severe symptoms which resolved within one month of onset. The symptoms developed a mean of 3.5 weeks following delivery, lasted 6.5 months and started to resolve within 14 days of weaning. Symptomatic treatments with either splintage, diuretics, non-steroidal anti-inflammatory drugs or steroid injections provided some benefit. Two patients required surgical decompression. All patients were symptom-free by one year.     

Xanthogranulomatous pyelonephritis with fatal outcome in a 2-month-old infant

A 2-month-old infant died of xanthogranulomatous pyelonephritis. Preoperatively pyonephrosis was suspected, because the child presented with a number of inflammatory, septic symptoms. Nephrectomy was performed and histopathology showed the kidney to be affected by xanthogranulomatous pyelonephritis. Postoperatively the child developed persistent attacks of fever and bronchopneumonia that led to his death with signs of pulmonary insufficiency.     

Monoclonal antibody to human high-molecular-weight kininogen recognizes its prekallikrein binding site and inhibits its coagulant activity

We developed a mouse monoclonal antibody (MoAb 115-21) to human high- molecular-weight kininogen (HK) that recognizes its prekallikrein binding site (residues 565 through 595 of HK). The corresponding synthesized 31-amino acid peptide (peptide IV) was recently shown to retain native HK's prekallikrein binding property. The same peptide bound factor XI also, although less avidly. Our MoAb recognizes purified HK, peptide IV, and the light chain moiety of HK (where the peptide IV resides), as shown by enzyme-linked immunosorbent assay (ELISA) and Western blotting experiments. The apparent dissociation constant for the HK and MoAb 115-21 interaction was 2.2 nmol/L. It does not recognize low-molecular-weight kininogen (LK) with which HK shares its heavy chain moiety or any antigens in human plasma congenitally deficient in kininogens. The binding of MoAb 115-21 to purified light chain of HK was competitively inhibited by peptide IV. In addition, the antibody inhibits HK-dependent clotting activity of normal human plasma and dextran sulfate-mediated activation of prekallikrein in plasma and retards cleavage of HK in normal plasma after contact activation with dextran sulfate. Also, purified Fab fragments of MoAb 115-21 inhibited the HK-dependent coagulant activity and dextran sulfate-mediated prekallikrein activation in normal plasma. Since the kd for HK-MoAb 115- 21 interaction is ten times lower than that of HK-prekallikrein, our data suggest that binding of MoAb 115-21 to HK's peptide IV site increases the free prekallikrein concentration in plasma and thus results in the decreased efficiency of factor XIIa-mediated activation of prekallikrein. Decreased levels of kallikrein thus formed may be responsible for the inhibition of HK-dependent clotting activity and the decrease in rate and extent of HK cleavage in normal plasma on contact activation with dextran sulfate. MoAb 115-21 may thus prove very useful, especially with its high affinity for HK, in further delineation of the role of HK and prekallikrein in contact activation and kinin-related human pathology.     

Translational development of splice-modifying antisense oligomers

Introduction: Antisense nucleic acid analogues can interact with pre-mRNA motifs and influence exon or splice site selection and thereby alter gene expression. Design of antisense molecules to target specific motifs can result in either exon exclusion or exon inclusion during splicing. Novel drugs exploiting the antisense concept are targeting rare, life-limiting diseases; however, the potential exists to treat a wide range of conditions by antisense-mediated splice intervention.

Areas covered: In this review, the authors discuss the clinical translation of novel molecular therapeutics to address the fatal neuromuscular disorders Duchenne muscular dystrophy and spinal muscular atrophy. The review also highlights difficulties posed by issues pertaining to restricted participant numbers, variable phenotype and disease progression, and the identification and validation of study endpoints.

Expert opinion: Translation of novel therapeutics for Duchenne muscular dystrophy and spinal muscular atrophy has been greatly advanced by multidisciplinary research, academic-industry partnerships and in particular, the engagement and support of the patient community. Sponsors, supporters and regulators are cooperating to deliver new drugs and identify and define meaningful outcome measures. Non-conventional and adaptive trial design could be particularly suited to clinical evaluation of novel therapeutics and strategies to treat serious, rare diseases that may be problematic to study using more conventional clinical trial structures.     

Sudden infant death syndrome and diphtheria-tetanus-pertussis-poliomyelitis vaccination status

Summary— Because diphtheria, tetanus, pertussis and poliomyelitis vaccine is routinely given during the period of highest incidence of sudden infant death syndrome (SIDS), we carried out a retrospective case-control study to assess whether such vaccination increased the risk of SIDS. The vaccination status of 118 SIDS and 332 control children, matched for sex, date of birth and age of the victims at death, was compared: the victims of SIDS were not significantly more often vaccinated than control children, the odds ratio was estimated at 1.9 with a 95% confidence interval from 0.9 to 3.9. There was a statistical difference between vaccination status of SIDS cases and controls aged less than three months. Nine percent of SIDS cases under 3 months had been vaccinated whereas the matched controls had not. In our study DTCP vaccination was not a risk factor for SIDS; although more of the SIDS infants less than 3 months of age had been vaccinated. This result however, concerns only one subgroup of the population studied and needs to be confirmed with another study of only SIDS infants less than 3 months of age, because DTCP vaccination was not a risk factor for SIDS when considering the total sample of the study.     

Zero tolerance: A policy in conflict with current opinion on aggression and violence management in health care

Aggression and violence are common in the emergency department setting. In recent years, there has been a greater recognition of this problem with State Governments in Australia responding with zero tolerance policies. This paper examines the current recommendations from nursing and medical literature with regard to the minimisation and management of aggression and violence in health care. A consistent theme throughout the literature is that early recognition and use of de-escalation strategies aimed at diffusing a volatile situation is the preferred approach. Use of restraint and a zero tolerance approach are last resort measures. It is important to have practical policies, protocols and procedures in place to manage aggression and violence in the emergency department. An emphasis on training and skill development, particularly communication and negotiation strategies, is imperative for all health care professionals.     

Diabetes insipidus.

OBJECTIVES: To review the pathophysiology, diagnosis, and treatment of the syndromes of diabetes insipidus with an emphasis on those situations likely to be encountered in the critical care setting. DATA SOURCES: Extensive clinical experience and relevant publications from the English literature identified via MEDLINE search, citation in reviews, publications of original data, and endocrine texts. STUDY SELECTION AND DATA EXTRACTION: Landmark papers pertaining to all aspects of diabetes insipidus were selected. Reviews, primary articles, and case reports pertaining to diabetes insipidus in the critical care setting were identified and selected according to their content of clinically useful information. DATA SYNTHESIS AND CONCLUSIONS: Diabetes insipidus may result from impaired synthesis and release of vasopressin from the hypothalamic-pituitary unit (neurogenic) or renal insensitivity to circulating vasopressin (nephrogenic). A number of interventions, diseases, and drugs commonly encountered in the critical care setting may result in the development or exacerbation of diabetes insipidus. The diagnosis of diabetes insipidus requires the exclusion of other causes of polyuria and a systematic demonstration of the response of homeostatic mechanisms to controlled dehydration. The treatment of diabetes insipidus depends on many factors, including the clinical setting, degree and pathophysiologic classification, ability of the patient to compensate for free water losses, and expected duration of the abnormality. Underlying disorders should be treated appropriately whenever possible.     

Transfusion-related acute lung injury caused by an NB2 granulocyte- specific antibody in a patient with thrombotic thrombocytopenic purpura

HLA and granulocyte-specific antibodies have been implicated in the production of transfusion-related acute lung injury (TRALI). Reported here is a case that suggests that the patient's preexisting condition may play an important role in determining whether TRALI develops upon transfusion of blood products containing anti-white cell (WBC) antibodies. A 29-year-old woman with thrombotic thrombocytopenic purpura (TTP) underwent an uneventful 1.5-volume plasma exchange, which was followed by the transfusion of 2 red cell (RBC) units. At the end of the second RBC transfusion, the patient developed clinical signs and symptoms of noncardiogenic pulmonary edema. Serologic studies demonstrated that the serum from the second RBC donor had no HLA antibodies but did have a granulocyte-specific antibody (anti-NB2) that caused the agglutination of the recipient's granulocytes, which were NB2 positive. Serum from the donor of the first RBC unit and serum from the donors of units used in the exchange had no HLA or granulocyte-specific antibodies that reacted with the recipient's WBCs. Because the donor implicated in this reaction had a history of 21 blood donations, none of which had been associated with a transfusion reaction, we suggest that the patient's preexisting condition played a significant role in this episode of TRALI, owing to the granulocyte-specific antibody.