Dynein light chain binding to a 3'-untranslated sequence mediates parathyroid hormone mRNA association with microtubules

The 3'-untranslated region (UTR) of mRNAs binds proteins that determine mRNA stability and localization. The 3'-UTR of parathyroid hormone (PTH) mRNA specifically binds cytoplasmic proteins. We screened an expression library for proteins that bind the PTH mRNA 3'-UTR, and the sequence of 1 clone was identical to that of the dynein light chain LC8, a component of the dynein complexes that translocate cytoplasmic components along microtubules. Recombinant LC8 binds PTH mRNA 3'-UTR, as shown by RNA electrophoretic mobility shift assay. We showed that PTH mRNA colocalizes with microtubules in the parathyroid gland, as well as with a purified microtubule preparation from calf brain, and that this association was mediated by LC8. To our knowledge, this is the first report of a dynein complex protein binding an mRNA. The dynein complex may be the motor that is responsible for transporting mRNAs to specific locations in the cytoplasm and for the consequent is asymmetric distribution of translated proteins in the cell.

An axonemal dynein at the Hybrid Sterility 6 locus: implications for t haplotype-specific male sterility and the evolution of species barriers

Poor sperm motility characterized by a distinct aberration in flagellar waveform known as "curlicue" is a hallmark of t haplotype (t) homozygous male sterility. Previous studies have localized "curlicue" and a flagellar developmental defect, "whipless", to the Hybrid Sterility 6 locus (Hst6), between the markers Pim1 and Crya1. More recent heterospecific breeding experiments between Mus spretus (Spretus) and Mus musculus domesticus (Domesticus) have mapped the primary source(s) of both "curlicue" and "whipless" to a small sub-locus of Hst6, Curlicue a (Ccua). Here we report the complete physical isolation of the Ccua locus and the identification of a candidate gene for expression of both "whipless" and "curlicue" at its proximal end, an axonemal dynein heavy chain gene, Dnahc8, formerly mapped by interspecific backcross analysis near Pim1. Dnahc8 mRNA expression commences in the Domesticus wild-type testis just prior to flagellar assembly and is testis-specific in the adult male. However, expression of Dnahc8 is not readily evident in the testis of either Spretus or "whipless" animals (Domesticus males homozygous for the Spretus allele of Dnahc8). Our results argue that Dnahc8 is fundamental to flagellar organization and function in Domesticus, but not Spretus, and suggest that Dnahc8 is integral to both Hst6- and t-specific male infertility.

Toronto street youth and HIV/AIDS: prevalence, demographics, and risks

PURPOSE

The purposes of this study were: (a) to identify human immunodeficiency virus (HIV) prevalence in Toronto street youth through paired blood and saliva specimens; (b) to identify the HIV risk and prevention behaviors of street involved youth; and (c) to identify demographic or other factors that may contribute to the risk of street youth becoming infected with HIV/acquired immunodeficiency syndrome (AIDS) in the future.

METHODS

This was a cross-sectional convenience study of street-involved youth aged 14-25 years. The youth participated in interviews to identify HIV-related knowledge and personal risk and preventive behaviors. Following interviews, they were asked to provide a saliva sample, blood spot, or both. They could refuse one or both samples without jeopardizing their involvement or receiving an honorarium. Two males were the only participants who declined to provide a sample.

RESULTS

Fifteen of 695 (2.2%) youth tested positive for HIV infection. All were male, ranging in age from 18 to 25 years. Same and opposite sex, intravenous (IV) drug use, prostitution, and incarceration were risk factors associated with positive HIV test results. The rate of HIV infection was seven times greater for the group 20 years of age and older (20-25) compared to the younger group aged 14-9 years. The proportion testing positive for HIV from small cities, towns, and rural communities in Ontario was 40%; yet, they represented 21% of the study population. Most (57%) youth had been on their own for no more than 3 years and had moved frequently. Nearly two thirds (60%) had stayed in hostels or homeless shelters in the previous 6 months.

CONCLUSION

Street youth in Canada are at high risk of HIV infection with their risk increasing with age. Unprotected (same and opposite) sex, IV drug use, prostitution and incarceration were linked to their HIV infections. The high level of mobility identified by street youth challenges governments, communities, and public health officials to develop appropriate prevention strategies and to carefully monitor the spread of HIV infection in this vulnerable population.

LC2, the chlamydomonas homologue of the t complex-encoded protein Tctex2, is essential for outer dynein arm assembly

Tctex2 is thought to be one of the distorter genes of the mouse t haplotype. This complex greatly biases the segregation of the chromosome that carries it such that in heterozygous +/t males, the t haplotype is transmitted to >95% of the offspring, a phenomenon known as transmission ratio distortion. The LC2 outer dynein arm light chain of Chlamydomonas reinhardtii is a homologue of the mouse protein Tctex2. We have identified Chlamydomonas insertional mutants with deletions in the gene encoding LC2 and demonstrate that the LC2 gene is the same as the ODA12 gene, the product of which had not been identified previously. Complete deletion of the LC2/ODA12 gene causes loss of all outer arms and a slow jerky swimming phenotype. Transformation of the deletion mutant with the cloned LC2/ODA12 gene restores the outer arms and rescues the motility phenotype. Therefore, LC2 is required for outer arm assembly. The fact that LC2 is an essential subunit of flagellar outer dynein arms allows us to propose a detailed mechanism whereby transmission ratio distortion is explained by the differential binding of mutant (t haplotype encoded) and wild-type dyneins to the axonemal microtubules of t-bearing or wild-type sperm, with resulting differences in their motility.

Small-Angle Neutron Scattering and Fluorescence Studies of Mixed Surfactants with Dodecyl Tails

The mixed micelles formed in solutions of the anionic surfactant sodium dodecylsulfate (SDS) and the nonionic surfactant dodecylmalono-bis-N-methylglucamide (DBNMG) were studied by surface tension, fluorescence, and small-angle neutron scattering. Measurements of the critical micelle concentration (CMC) by surface tension and fluorescence show that these two surfactants mix nonideally. The experimental values of the CMCs for surfactant mixtures for all compositions are less than the ideal prediction proposed by Clint (J. Chem. Soc. 71, 1327 (1975)). Regular solution theory (for example, Penfold et al., Langmuir 11, 2498 (1995)) can be used to calculate the composition of the micelle at the CMC. The micellar composition thus calculated differs significantly from that at higher total surfactant concentrations, the latter being much closer to the stoichiometric composition. The polarity of the micellar environment, as perceived by a solubilized fluorescence probe, is identical for both the single-component and the mixed micelles. The scattering data show that the mixed micelles are comparable in size to the pure nonionic micelle and slightly larger than the anionic micelle. Parallel studies with deuterated SDS showed no evidence of segregation or local ordering within the mixed micelle. The effective charge on the mixed micelle is determined by the amount of ionic surfactant within the micelle. Addition of 0.1 M NaCl to these systems has no effect on the CMC, micelle ellipticity, and aggregation number-a behavior very different from that observed for simple SDS solutions. Copyright 1999 Academic Press.

Light chain 1 from the Chlamydomonas outer dynein arm is a leucine-rich repeat protein associated with the motor domain of the gamma heavy chain

The LC1 light chain from Chlamydomonas outer arm dynein is tightly bound to the gamma heavy chain. Molecular cloning revealed that LC1 is a member of the SDS22+ subclass of the leucine-rich repeat protein family and as such is likely involved in mediating interactions between dynein and the components of a signal transduction pathway. Through the combination of covalent cross-linking and vanadate-mediated photolysis, LC1 was found to associate with that portion of the gamma HC that is C-terminal to the P1 loop. This region comprises most of the globular head domain of the heavy chain and includes the stalk-like structure that is involved in microtubule binding. Attachment of LC1 to this region represents the only known example of an accessory polypeptide directly associated with a dynein motor domain. Additional cross-linking experiments revealed that LC1 also interacts directly in situ with an approximately 45 kDa axonemal component; this interaction is disrupted by the standard high salt treatment used to remove the outer arm from the axoneme. These data suggest that LC1 acts to mediate the association between this 45 kDa axonemal polypeptide and the motor unit of the gamma HC.

Assigning secondary structure from protein coordinate data

We have developed a program to convert the three dimensional coordinates describing protein structure in the Brookhaven Data Bank into an assignment of secondary structure. The program assigns secondary structure in the same way a person assigns structure visually. It uses two angles and three distances to assign alpha-helix, 3(10)-helix, beta-strand, hydrogen-bonded beta-turn, non-hydrogen-bonded beta-turn, and poly (L-proline) II type 3(1)-helix. The program is concerned with amide-amide interactions and should be particularly useful to spectroscopists.

The proapoptotic activity of the Bcl-2 family member Bim is regulated by interaction with the dynein motor complex

Bcl-2 family members that have only a single Bcl-2 homology domain, BH3, are potent inducers of apoptosis, and some appear to play a critical role in developmentally programmed cell death. We examined the regulation of the proapoptotic activity of the BH3-only protein Bim. In healthy cells, most Bim molecules were bound to LC8 cytoplasmic dynein light chain and thereby sequestered to the microtubule-associated dynein motor complex. Certain apoptotic stimuli disrupted the interaction between LC8 and the dynein motor complex. This freed Bim to translocate together with LC8 to Bcl-2 and to neutralize its antiapoptotic activity. This process did not require caspase activity and therefore constitutes an initiating event in apoptosis signaling.

Escape-related behaviours in an unstable elevated and exposed environment. I. A new behavioural model of extreme anxiety

The aim of this study was to validate a new behavioural test for extreme anxiety, designed to elicit unconditioned escape from animals on an unstable, elevated and exposed plus maze. The animals were also run on a standard elevated plus maze, so that well-validated anxiety measures could be compared with the animals' propensity to escape. The first experiment compared the behavioural repertoire of three rat strains; more escape behaviours were elicited from the Sprague Dawleys (SDs) and dark agouti (DAs) than from the hooded listers (HLs) on the unstable maze. Similarly, the SDs and DAs exhibited higher anxiety profiles than the HLs on the standard plus maze. There was a clear correlation, therefore, between the propensity to escape and well-validated anxiety measures. A further group of rats [HLs] was tested on both the unstable and standard plus mazes (Experiment 2) and principal components analyses carried out on all behavioural measures. The extracted factors identified separate and independent factors relating to escape-linked behaviours on the unstable plus maze and anxiety on the standard plus maze. The escape-linked behaviours exhibited on the unstable plus maze appear to reflect a different type of anxiety from that exhibited on the standard plus maze. The bias towards escape behaviours shown by some rats on the unstable plus maze may mimic the chronically hyper-aroused, persistent 'fight/flight' state exhibited by certain categories of anxiety patients, and hence provide a behavioural model of extreme anxiety.

Escape-related behaviours in an unstable, elevated and exposed environment. II. Long-term sensitization after repetitive electrical stimulation of the rodent midbrain defence system

The behavioural indices of anxiety/fear/panic range from freezing/inhibition of ongoing behaviour to active defence strategies i.e. fight/flight, depending on the proximity or intensity of the aversive stimulus. However, evidence suggests that when the initial stressor is sufficiently intense, the neural defence circuitry may undergo a long-term increase in sensitivity. Such sensitization has been evoked to explain the chronically hyper-aroused fight/flight state of patients suffering from extreme anxiety states. The purpose of this study was to establish whether direct activation of the rodent midbrain defence system could result in a similar long-term alteration of the animal's responses to subsequent stressful events. This was achieved by studying the behaviour of animals in a threatening environment after repetitive electrical stimulation of the superior colliculus. Animals were then placed on an unstable, elevated and exposed plus maze and their behaviour recorded. Testing was carried out regularly over 3 months. Stimulated animals reliably exhibited significantly increased levels of behaviours designed to escape the aversive conditions of the unstable plus maze. These included visual scanning, end-reaching, preparing to jump, and jumping off the apparatus. Unstimulated control animals, on the other hand, exhibited decreased levels of these behaviours post-stimulation. In contrast, the experimental animals' performance on standard anxiety tests did not differ from controls. These results demonstrate that repetitive tactile stimulation can produce a long-term change in reactions to threat, and is proposed as a functional model of extreme anxiety.

Cytoplasmic dynein contains a family of differentially expressed light chains

Cytoplasmic dynein contains a series of accessory proteins associated with the motor containing heavy chains.1 These include three distinct classes of light chains (Mr < approximately 22 000). Here we demonstrate that a previously cloned protein termed rp3 is a bona fide Mr 14 000 light chain component of this microtubule motor complex. The rp3 polypeptide is approximately 55% identical to the Tctex1 dynein light chain, and together, these two proteins define one branch of a diverse family of Mr 14 000 light chains associated with both cytoplasmic and flagellar dyneins. The Tctex1 and rp3 light chains are differentially expressed in various tissues: rp3 is most prevalent in liver and brain cytoplasmic dynein, whereas those tissues contain the least amounts of Tctex1. Immunofluorescence analysis was consistent with the tissue-specific distribution of these proteins and revealed that both rp3 and Tctex1 are present in multiple perinuclear punctate particles. Furthermore, in two cell lines, rp3 was found associated with an elongated structure located in the layer of cytoplasm above the nucleus. Electrophoretic/immunological analysis indicates that there are only single isoforms for these proteins in brain and PC-12 cells, suggesting that alterations in the Mr 14 000 light chains of dynein are achieved at the level of the individual proteins and not by posttranslational modification. Dissection of the cytoplasmic dynein complex revealed that Tctex1, an Mr 8000 LC dimer, and IC74 associate to define a basal-located intermediate chain/light chain complex analogous to that found in flagellar outer arm dynein.

Notifying patients exposed to blood products associated with Creutzfeldt-Jakob disease: theoretical risk for real people

BACKGROUND

In July 1995 the Canadian Red Cross Society recalled blood products because of the hypothetical risk of transmission of Creutzfeldt-Jakob disease (CJD) through those blood products. The authors undertook a survey to determine the views of patients and parents of patients about being notified that they or their child had received such blood products.

METHODS

The study population consisted of 528 transfusion recipients, of whom 453 (85.8%) were under 16 years of age, notified by the Hospital for Sick Children, Toronto, of the CJD recalls in 1995 and 1996. Families attending an information session were asked to complete a self-administered questionnaire (85 cases). Ninety-seven families randomly selected from those who did not attend the session were interviewed by telephone. The questionnaire was adapted from a questionnaire used to evaluate families' responses to notification of transfusion and risk of HIV infection.

RESULTS

More than 80% of the respondents said they wanted to be notified and would want to be notified if there were another recall. On initial receipt of the notification about two-thirds of the respondents had been anxious, fearful or angry. There was no one method of conveying the information that suited all, but a personalized letter was seen as the most acceptable method.

INTERPRETATION

Most parents of children who have received blood products are in favour of being informed about the risk of CJD, despite the uncertainty of the information on risk and the anxiety that such information causes.

Serum immunoreactive erythropoietin levels and associated factors amongst HIV-infected children

OBJECTIVES

To determine the spectrum of serum immunoreactive erythropoietin (SIE) levels amongst HIV-infected children aged < 13 years in relation to the levels among healthy children as well as those with renal failure; to examine the relationship between clinical and laboratory parameters and SIE levels.

DESIGN

A cross-sectional study with a descriptive non-interventional format. HIV-infected Canadian subjects were recruited through four tertiary Canadian and one Bahamian centre. Children with renal failure and healthy children were recruited from one of the Canadian centres.

METHODS

Study subjects had clinical and laboratory profiles determined at baseline and at each of five follow-up periods over 1 year. SIE levels were measured by radioimmunoassay with a normal range of 12-28 IU/I. Data handling and statistical functions were performed by the Canadian HIV Trials Network.

RESULTS

The study enrolled 133 HIV-infected subjects and 38 controls. Of these, 117 HIV-infected subjects, 24 healthy controls, and 11 controls with renal failure were eligible for analysis. The median age of infected subjects was 44 months, whereas that of healthy controls was 56 months, and 95 months for controls with renal failure. The median SIE levels were 14 and 11 IU/I for subjects with renal failure and healthy subjects, respectively. The median SIE level was 61 IU/I among zidovudine (ZDV)-treated subjects and 22 IU/I among ZDV-naive HIV-infected subjects. HIV-infected children almost invariably had SIE levels < 200 IU/I. The median SIE levels amongst HIV-infected subjects whose hemoglobin levels were < 100 g/l were 98 and 31 IU/I for ZDV-treated and ZDV-naive subjects, respectively (P = 0.002). This difference in median SIE levels between ZDV-treated subjects and ZDV-naive subjects was also observed among subjects whose hemoglobin levels were > 100 g/l (median, 58 and 15 IU/l, respectively; P < 0.001). Hemoglobin level was the most important predictor of log10 SIE (P < 0.01 for ZDV-treated and ZDV-naive subjects).

CONCLUSIONS

SIE levels amongst HIV-infected children were affected by HIV infection, use of ZDV, and presence or absence of anemia. SIE levels amongst HIV-infected children were generally lower than 200 IU/I. This characterization of SIE levels will facilitate clinical trials of exogenous recombinant human erythropoietin in HIV-infected children with anemia.

The APCI1307K allele and cancer risk in a community-based study of Ashkenazi Jews

Mutations in APC are classically associated with familial adenomatous polyposis (FAP), a highly penetrant autosomal dominant disorder characterized by multiple intestinal polyps and, without surgical intervention, the development of colorectal cancer (CRC). APC is a tumour-suppressor gene, and somatic loss occurs in tumours. The germline T-to-A transversion responsible for the APC I1307K allele converts the wild-type sequence to a homopolymer tract (A8) that is genetically unstable and prone to somatic mutation. The I1307K allele was found in 6.1% of unselected Ashkenazi Jews and higher proportions of Ashkenazim with family or personal histories of CRC (ref. 2). To evaluate the role of I1307K in cancer, we genotyped 5,081 Ashkenazi volunteers in a community survey. Risk of developing colorectal, breast and other cancers were compared between genotyped I1307K carriers and non-carriers and their first-degree relatives.

Sequential use of intravenous and oral acyclovir in the therapy of varicella in immunocompromised children

BACKGROUND

Immunocompromised children are at risk for disseminated varicella infections. Standard management involves hospitalization and intravenous acyclovir for 7 to 10 days. This approach is expensive, is inconvenient and may not be necessary. We undertook a pilot study to assess the safety and efficacy of an alternative approach that utilized a combination of intravenous (i.v.) followed by oral (p.o) acyclovir in a cohort of immunocompromised children.

METHODS

The cohort consisted of 26 immunocompromised children between the ages of 1.5 and 12.7 years (mean, 6.3). Therapy was commenced with i.v. acyclovir (1500 mg/m2/day in 3 divided doses). Concurrent management included holding or reducing immunosuppressive therapy (by 50%) and administering varicella-zoster immunoglobulin in 69% (11 of 16) of cases where exposure to chickenpox was recognized. Patients were eligible to switch to p.o therapy after receiving a minimum of 48 h of i.v. acyclovir therapy provided they were afebrile; had no new lesions for 24 h; had no internal organ involvement and were able to tolerate oral medications. Patients were observed in hospital for a further 24 h and then discharged provided they remained well. Oral acyclovir was continued for a total of 7 to 10 days (i.v. plus p.o).

RESULTS

Of the 26 patients 25 were successfully switched from i.v. to p.o after 4.1 +/- 1.2 days (mean +/- SD) (range, 2.3 to 6) Children had fever for a mean of 2.0 +/- 1.6 days (range, 0 to 5) and developed new lesions for 2.9 +/- 0.7 days (range, 2 to 4). All 25 patients switched to p.o therapy had resolution of their disease and no patient required resumption of i.v. therapy.

CONCLUSIONS

The sequential use of i.v. followed by p.o acyclovir is feasible in the treatment of varicella in immunocompromised children and results in a reduction in duration of intravenous therapy and hospitalization.

Hepatitis C in children after transfusion: assessment by look-back studies

Look-back studies to identify paediatric patients with post-transfusion hepatitis C have been conducted at several tertiary-care hospitals in Canada. A general look-back study was conducted at the Hospital for Sick Children in Toronto for the time period December 1985 to May 1990. All patients transfused at the Hospital for Sick Children during this time period were identified from hospital Blood Bank records. Letters of notification were sent by registered mail to all recipients excluding those known to have died. In the letter anti-HCV testing was recommended. Letters were mailed to 6332 transfusion recipients; 4496 letters were delivered. Of these 146 anti-HCV-positive transfusion recipients (92 pts < 18 yrs old; 54 pts > 18 yrs old) were identified. Sixty-four of these patients were definitely transfused only during this time period. Assuming that all notified patients were tested, the minimum prevalence of new infection in this time period was 1.4%. When possible, identified patients were tested for presence of HCV RNA in the serum by RT-PCR. The proportion of patients anti-HCV positive but HCV RNA negative on one or more occasions was similar in both whole cohort and subset: approximately one-third. These data suggest that chronic hepatitis C may be less likely to develop after transfusion in children than in adults.

Identification of the t complex-encoded cytoplasmic dynein light chain tctex1 in inner arm I1 supports the involvement of flagellar dyneins in meiotic drive

The cytoplasmic dynein light chain Tctex1 is a candidate for one of the distorter products involved in the non-Mendelian transmission of mouse t haplotypes. It has been unclear, however, how the t-specific mutations in this protein, which is found associated with cytoplasmic dynein in many tissues, could result in a male germ cell-specific phenotype. Here, we demonstrate that Tctex1 is not only a cytoplasmic dynein component, but is also present both in mouse sperm and Chlamydomonas flagella. Genetic and biochemical dissection of the Chlamydomonas flagellum reveal that Tctex1 is a previously undescribed component of inner dynein arm I1. Combined with the recent identification of another putative t complex distorter, Tctex2, within the outer dynein arm, these results support the hypothesis that transmission ratio distortion (meiotic drive) of mouse t haplotypes involves dysfunction of both flagellar inner and outer dynein arms but does not require the cytoplasmic isozyme.

Erythrocyte insulin-like growth factor-L binding in younger and older males

OBJECTIVE

Insulin-like growth factor-1 (IGF-l) levels are lower in older compared with younger subjects. We tested the hypothesis that the reduction in circulating IGF-l would be accompanied by upregulation in tissue IGF-l binding in at least some tissues. We tested erythrocyte IGF-l binding since blood is an accessible tissue in humans, and there is growing evidence to suggest that erythrocyte IGF-l binding is influenced by circulating IGF-l.

DESIGN AND PATIENTS

We compared 9 healthy older males (61-68 years old) with 9 healthy younger males (15-19 years old).

MEASUREMENTS

Standard techniques were used to assay circulating IGF-l and IGF binding proteins 1-5 (IGFBPs 1-5). Erythrocyte IGF-l binding was first measured by studies in which native [125l]-IGF-l was displaced with unlabelled native IGF-l. In order to determine a possible role for IGF binding proteins (IGFBP), native [125l]-IGF-l was displaced with des-(1-3)IGF-1, which binds with IGF receptors but not IGFBPs.

RESULTS

As expected, circulating IGF-l was significantly lower in the older compared with the younger subjects. In addition, IGFBP-3 and 5 were significantly lower, and IGFBP-4 higher, in older compared with younger subjects. When native [125l]-IGF-l was displaced with unlabelled native IGF-l, the number of IGF-l binding sites per erythrocyte was higher in the older subjects (43 +/- 5 vs. 18 +/- 2, older vs. younger, respectively; P < 0.05). In contrast, when native [125l]-IGF-l was displaced with des-(1-3), IGF-l binding capacity was not different between the two age groups.

CONCLUSIONS

Erythrocyte IGF binding was increased in older compared with younger subjects. Surprisingly, the mechanism of the increase may not be a simple up regulation of IGF-l receptors in response to reduced circulating IGF-l, but possibly by an increase in the levels of as yet unidentified erythrocyte membrane-associated IGF binding proteins.

Randomized comparison of ganciclovir plus intravenous immune globulin (IVIG) with IVIG alone for prevention of primary cytomegalovirus disease in children receiving liver transplants

A randomized placebo-controlled trial was conducted to determine the benefit of ganciclovir (5 mg/[kg x d]) for 30 days in addition to intravenous immune globulin (IVIG) for 16 weeks for prevention of primary cytomegalovirus (CMV) disease in children receiving liver transplants. Patients were monitored for 6 months after transplantation. The two groups of patients (recipients of 29 ganciclovir plus IVIG and 27 recipients of IVIG alone) were similar in terms of age, sex, and underlying disease. The incidence of CMV disease among the ganciclovir plus IVIG recipients and the IVIG alone recipients was 17% and 26%, respectively, and the time to disease in these recipients was 46 days and 32 days, respectively. There was no difference between groups in terms of survival; episodes of rejection, bacteremia, or fungemia; use of immunosuppressive agents; and incidence of leukopenia or thrombocytopenia. These results suggest that a 4-week course of ganciclovir with IVIG is not more effective than IVIG alone for prevention of primary CMV disease. Since short-term prophylaxis with ganciclovir may delay the onset of CMV disease, further studies with a longer course of ganciclovir prophylaxis are warranted.

Adverse reactions to trimethoprim-sulfamethoxazole among children with human immunodeficiency virus infection

BACKGROUND

The clinical course of HIV infection is frequently different among infants and children from that in adults. In adults among the most common sources of morbidity related to therapy are adverse drug reactions, notably to trimethoprim-sulfamethoxazole. Although there are case reports of serious adverse reactions to trimethoprim-sulfamethoxazole among infants and children with HIV infection, the precise rate and clinical characteristics of these adverse reactions among HIV-infected children are unknown.

METHODS

We reviewed the clinical records of all children referred to a regional HIV clinic in a 6-year period. Therapy and suspected adverse drug reactions to therapy were reviewed by one of the investigators not involved in patient care. Adverse drug reactions were identified and characterized according to previously established criteria.

RESULTS

During this time 78 children were referred for assessment of possible HIV infection, 45 of whom were ultimately determined to have the infection. Twenty-five were treated with trimethoprim-sulfamethoxazole, 15 (60%) of whom tolerated therapy and 10 (40%) of whom had adverse reactions. The most common type of adverse reaction was erythema multiforme (70%), followed by neutropenia (20%) and Stevens-Johnson syndrome (10%). In two patients a serious adverse reaction to trimethoprim-sulfamethoxazole led to the diagnosis of HIV infection.

CONCLUSIONS

The overall incidence and type of serious adverse reactions to trimethoprim-sulfamethoxazole among infants and children with HIV infection appear to be similar to those among adults.