Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Abstract P3-03-05: Establishment and evaluation of ER+ breast cancer models using an optimized methodology for exogenous hormone delivery

Preclinical in vivo models of estrogen receptor positive (ER+) breast cancer rely on exogenous supplementation of hormones for growth. This requirement leads to animal toxicity and mortality over time, limiting development and drug testing in these types of models. Efficacy of test agents, particularly endocrine therapies, may also be altered in these models due to excessive hormone exposure, highlighting the need to improve methods for the establishment and testing of ER+ breast models.

We have developed an alternative method of hormone supplementation in ER+ breast cancer models and optimized this method for testing of endocrine therapies. Using two cell-based breast models, we demonstrated improved breast tumor take and time to tumor volume endpoint while reducing animal toxicity and mortality associated with standard hormone supplementation. Subsequent studies identified the lowest effective dose (LED) of supplement for hormone dependent model growth with a preclinically relevant time to tumor volume endpoint. Activity of endocrine therapies including tamoxifen, letrozole, fulvestrant and exemestane were compared at the standard and LED hormone concentrations. In these studies tamoxifen treatment resulted in tumor regressions which was not appreciably improved using the LED dose of supplement. However letrozole activity was improved in the LED study suggesting hormone supplementation can impact activity of some agents. Using this process we also generated a panel of ER+ patient-derived xenograft (PDX) models, including two novel hormone therapy responsive models from chemo-naïve or hormone therapy pretreated patients, designated ST986 and ST2177, respectively.

This improved method of hormone supplementation diminishes the adverse effects of standard hormone supplementation and provides utility for development of anticancer therapies in ER+ breast models.

Citation Format: Wick MJ, Vaught T, Meade J, Gamez L, Farley M, Tolcher AW, Rasco D, Patnaik A, Drengler RL, Rosenthal A, Papadopoulos KP. Establishment and evaluation of ER+ breast cancer models using an optimized methodology for exogenous hormone delivery. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-03-05.

A high-density SNP genome-wide linkage scan in a large autism extended pedigree

We performed a high-density, single nucleotide polymorphism (SNP), genome-wide scan on a six-generation pedigree from Utah with seven affected males, diagnosed with autism spectrum disorder. Using a two-stage linkage design, we first performed a nonparametric analysis on the entire genome using a 10K SNP chip to identify potential regions of interest. To confirm potentially interesting regions, we eliminated SNPs in high linkage disequilibrium (LD) using a principal components analysis (PCA) method and repeated the linkage results. Three regions met genome-wide significance criteria after controlling for LD: 3q13.2-q13.31 (nonparametric linkage (NPL), 5.58), 3q26.31-q27.3 (NPL, 4.85) and 20q11.21-q13.12 (NPL, 5.56). Two regions met suggestive criteria for significance 7p14.1-p11.22 (NPL, 3.18) and 9p24.3 (NPL, 3.44). All five chromosomal regions are consistent with other published findings. Haplotype sharing results showed that five of the affected subjects shared more than a single chromosomal region of interest with other affected subjects. Although no common autism susceptibility genes were found for all seven autism cases, these results suggest that multiple genetic loci within these regions may contribute to the autism phenotype in this family, and further follow-up of these chromosomal regions is warranted.

Physical symptoms, posttraumatic stress disorder, and healthcare utilization of women with and without childhood physical and sexual abuse

For four groups of women: no abuse, physical abuse alone, combined sexual and physical abuse, and unclear about memories of abuse, we examined the associations between childhood sexual and physical abuse, chronic physical symptoms in adulthood, PTSD, and health care utilization. Of a randomly selected sample of 600 adult femalc members of a health maintenance organization, 86 (14%) chose to participate. Women with a history of physical and sexual abuse in childhood reported significantly more cardiovascular, immune, musculoskeletal, neurologic, and reproductive symptoms than those without this history. While the Sexual/Physical Abuse group had the most chronic physical symptoms, medical visits, emergency room visits, prescriptions, and severe PTSD, the Unclear Memory group consistently ranked second on these same measures--higher than either Controls or the Physical Abuse group. Findings underscore the importance of screening for trauma history among patients seen in medical clinics, and the importance for psychotherapists of attending to patients' physical as well as psychological symptoms of childhood trauma.

Nevoid basal cell carcinoma syndrome and non-Hodgkin's lymphoma

Nevoid basal cell carcinoma syndrome (NBCCS) is a hereditary disorder with a predilection for numerous basal cell carcinomas in addition to odontogenic keratocysts, palmoplantar pitting, and skeletal malformations. NBCCS has been associated with a number of benign and malignant neoplasms. We report the first case of NBCCS in association with non-Hodgkin's lymphoma.

The pressor response to water drinking in humans : a sympathetic reflex?

BACKGROUND

Water drinking increases blood pressure profoundly in patients with autonomic failure and substantially in older control subjects. The mechanism that mediates this response is not known.

METHODS AND RESULTS

We studied the effect of drinking tap water on seated blood pressure in 47 patients with severe autonomic failure (28 multiple system atrophy [MSA], 19 pure autonomic failure patients [PAF]). Eleven older controls and 8 young controls served as control group. We also studied the mechanisms that could increase blood pressure with water drinking. Systolic blood pressure increased profoundly with water drinking, reaching a maximum of 33+/-5 mm Hg in MSA and 37+/-7 in PAF mm Hg after 30 to 35 minutes. The pressor response was greater in patients with more retained sympathetic function and was almost completely abolished by trimethaphan infusion. Systolic blood pressure increased by 11+/-2.4 mm Hg in elderly but not in young controls. Plasma norepinephrine increased in both groups. Plasma renin activity, vasopressin, and blood volume did not change in any group.

CONCLUSIONS

Water drinking significantly and rapidly raises sympathetic activity. Indeed, it raises plasma norepinephrine as much as such classic sympathetic stimuli as caffeine and nicotine. This effect profoundly increases blood pressure in autonomic failure patients, and this effect can be exploited to improve symptoms due to orthostatic hypotension. Water drinking also acutely raises blood pressure in older normal subjects. The pressor effect of oral water is an important yet unrecognized confounding factor in clinical studies of pressor agents and antihypertensive medications.

Variations of the pursestring suture in skin cancer reconstruction

BACKGROUND

The pursestring suture (PSS) utilizes a circumferentially placed intradermal suture to decrease the size of a defect. Its primary application in dermatologic surgery has been to allow placement of a smaller full-thickness skin graft and to enhance secondary intention wound healing.

OBJECTIVE

To present our experience with 3 variations of the PSS.

METHODS

The oval defects resulting after surgical excision of cutaneous malignancies were managed with 3 variations of the traditional pursestring technique. These variations included (1) complete closure of the PSS-reduced defect by the placement of traditional interrupted sutures; (2) PSS with the Burow's triangle graft; (3) use of a PSS only part way around an oval defect to avoid distortion of a nearby free margin.

RESULTS

In the 7 years of performing these variations of the PSS technique, we have consistently achieved favorable results.

CONCLUSION

We report 3 simple-to-use variations of the PSS technique that have been extremely useful in the management of cutaneous malignancies.

Risk factors for invasive pneumococcal disease in children: a population-based case-control study in North America

OBJECTIVE

To identify risk factors for invasive pneumococcal disease, including penicillin-resistant infections, among children 2 to 59 months of age.

DESIGN

Case-control study.

PARTICIPANTS

Patients with invasive pneumococcal infections identified by population-based surveillance (n = 187) and controls identified through random-digit telephone dialing (n = 280).

OUTCOME MEASURES

Invasive pneumococcal disease was defined as isolation of Streptococcus pneumoniae from a normally sterile site. Patients 2 to 59 months of age who were residents of one of four active surveillance areas were included. S pneumoniae isolates were tested by broth microdilution. Isolates with a minimum inhibitory concentration to penicillin >/=2 microg/mL were considered resistant.

RESULTS

Invasive pneumococcal disease was strongly associated with underlying disease and with day care attendance in the previous 3 months. Among 2- to 11-month-olds, current breastfeeding was associated with a decreased likelihood of invasive pneumococcal disease (odds ratio, 0.27; 95% confidence interval: 0.08, 0.90). Penicillin-resistant infections were independently associated with day care attendance, at least one course of antibiotics, and at least one ear infection in the previous 3 months.

CONCLUSIONS

This study shows the association of underlying illnesses, day care attendance, and lack of breastfeeding with risk of invasive pneumococcal disease in children. The association of recent antibiotic use and infection with penicillin-resistant S pneumoniae highlights the need to avoid unnecessary antibiotic use in children.

Geocoding and linking data from population-based surveillance and the US Census to evaluate the impact of median household income on the epidemiology of invasive Streptococcus pneumoniae infections

The emergence of drug-resistant Streptococcus pneumoniae poses new clinical challenges and may also reflect a change in the epidemiology of S. pneumoniae infections. A variety of studies have shown that drug-resistant S. pneumoniae infections are linked to antimicrobial use. It has been hypothesized that persons of high socioeconomic status are at increased risk for a drug-resistant infection because of greater access to antimicrobial drugs. To assess whether median household income is associated with increased risk of penicillin-nonsusceptible S. pneumoniae infections, the authors geocoded and linked data from population-based surveillance for invasive pneumococcal disease with data from the 1990 US Census. Among invasive pneumococcal isolates from Atlanta, Georgia, in 1994, increasing proportions of penicillin-nonsusceptible isolates were associated with higher median household incomes (chi2 for trend, 15.17; p=0.002). Despite higher rates of invasive pneumococcal disease among blacks and persons who resided within lower median household income areas, white patients in areas with higher median household income had a higher risk of being infected with strains that were not susceptible to penicillin (Wilcoxon rank sum, Z=2.66, p=0.008). These findings demonstrated the utility of geocoding and US Census data in describing the epidemiology of drug-resistant S. pneumoniae and also provided more evidence that socioeconomic factors may influence the development of drug resistance.

Serum and cerebrospinal fluid pharmacokinetics of intravenous and oral lamivudine in human immunodeficiency virus-infected children

We studied the pharmacokinetics of intravenously and orally administered lamivudine at six dose levels ranging from 0.5 to 10 mg/kg of body weight in 52 children with human immunodeficiency virus infection. A two-compartment model with first-order elimination from the central compartment was simultaneously fitted to the serum drug concentration-time data obtained after intravenous and oral administration. The maximal concentration at the end of the 1-h intravenous infusion and the area under the concentration-time curve after oral and intravenous administration increased proportionally with the dose. The mean clearance of lamivudine (+/- standard deviation) in the children was 0.53 +/- 0.19 liter/kg/h (229 +/- 77 ml/min/m2 of body surface area), and the mean half-lives at the distribution and elimination phases were 0.23 +/- 0.18 and 2.2 +/- 2.1 h, respectively. Clearance was age dependent when normalized to body weight but age independent when normalized to body surface area. Lamivudine was rapidly absorbed after oral administration, and 66% +/- 25% of the oral dose was absorbed. Serum lamivudine concentrations were maintained above 1 microM for >/=8 h of 24 h on the twice daily oral dosing schedule with doses of >/=2 mg/kg. The cerebrospinal fluid drug concentration measured 2 to 4 h after the dose was 12% (range, 0 to 46%) of the simultaneously measured serum drug concentration. A limited-sampling strategy was developed to estimate the area under the concentration-time curve for concentrations in serum at 2 and 6 h.

Prostitution, violence, and posttraumatic stress disorder

One hundred and thirty people working as prostitutes in San Francisco were interviewed regarding the extent of violence in their lives and symptoms of posttraumatic stress disorder (PTSD). Fifty-seven percent reported that they had been sexually assaulted as children and 49% reported that they had been physically assaulted as children. As adults in prostitution, 82% had been physically assaulted; 83% had been threatened with a weapon; 68% had been raped while working as prostitutes; and 84% reported current or past homelessness. We differentiated the types of lifetime violence as childhood sexual assault; childhood physical abuse; rape in prostitution; and other (non-rape) physical assault in prostitution. PTSD severity was significantly associated with the total number of types of lifetime violence (r = .21, p = .02); with childhood physical abuse (t = 2.97, p = .004); rape in adult prostitution (Student's t = 2.77, p = .01); and the total number of times raped in prostitution (Kruskal-Wallace chi square = 13.51, p = .01). Of the 130 people interviewed, 68% met DSM III-R criteria for a diagnosis of PTSD. Eighty-eight percent of these respondents stated that they wanted to leave prostitution, and described what they needed in order to escape.

Determining the burden of human illness from food borne diseases. CDC's emerging infectious disease program Food Borne Diseases Active Surveillance Network (FoodNet)

Food borne diseases cause a significant burden of illness in the United States. The Food Borne Diseases Active Surveillance Network (FoodNet), established in 1995, continues to monitor the burden and causes of food borne diseases and provide much of the data to address this public health problem.

Bacterial meningitis in the United States in 1995. Active Surveillance Team

BACKGROUND

Before the introduction of the conjugate vaccines, Haemophilus influenzae type b was the major cause of bacterial meningitis in the United States, and meningitis was primarily a disease of infants and young children. We describe the epidemiologic features of bacterial meningitis five years after the H. influenzae type b conjugate vaccines were licensed for routine immunization of infants.

METHODS

Data were collected from active, population-based surveillance for culture-confirmed meningitis and other invasive bacterial disease during 1995 in laboratories serving all the acute care hospitals in 22 counties of four states (total population, more than 10 million). The rates were compared with those for 1986 obtained by similar surveillance.

RESULTS

On the basis of 248 cases of bacterial meningitis in the surveillance areas, the rates of meningitis (per 100,000) for the major pathogens in 1995 were Streptococcus pneumoniae, 1.1; Neisseria meningitidis, 0.6; group B streptococcus, 0.3; Listeria monocytogenes, 0.2; and H. influenzae, 0.2. Group B streptococcus was the predominant pathogen among newborns, N. meningitidis among children 2 to 18 years old, and S. pneumoniae among adults. Pneumococcal meningitis had the highest case fatality rate (21 percent) and in 36 percent of cases was caused by organisms that were not susceptible to penicillin. From these data, we estimate that 5755 cases of bacterial meningitis were caused by these five pathogens in the United States in 1995, as compared with 12,920 cases in 1986, a reduction of 55 percent. The median age of persons with bacterial meningitis increased greatly, from 15 months in 1986 to 25 years in 1995, largely as a result of a 94 percent reduction in the number of cases of H. influenzae meningitis.

CONCLUSIONS

Because of the vaccine-related decline in meningitis due to H. influenzae type b, bacterial meningitis in the United States is now a disease predominantly of adults rather than of infants and young children.

Estrone sulfatase: probing structural requirements for substrate and inhibitor recognition

The enzyme-catalyzed desulfation of steroids is a transformation that plays an important role in steroid biosynthesis. Conversion of steroid sulfates to unconjugated steroids may provide a source of steroids for processes such as steroid transport and the growth and proliferation of breast cancer. Steroid sulfatase catalyzes the hydrolysis of 3beta-hydroxysteroid sulfates. To identify structural features important in enzyme-inhibitor interaction, a variety of steroidal and non-steroidal phosphate esters were synthesized and tested as inhibitors of steroid sulfatase activity. We report that the basic structure for enzyme-inhibitor binding does not include the steroid nucleus. Furthermore, the hydrophobicity of the non-steroidal phosphates was determined to be an important factor for optimal inhibition. The monoanionic form of the phosphorylated compounds was found to be the inhibitory species. The best non-steroidal inhibitor of steroid sulfatase activity was n-lauroyl tryamine phosphate with a Ki of 3.6 microM and 520 nM at pH 7.5 and 7.0. The poorest non-steroidal based inhibitor of sulfatase activity was tetrahydronaphthyl phosphate with a Ki of 870 and 360 microM at pH 7.5 and 7.0.

Somatization, dissociation, and tension-reducing behaviors in psychiatric outpatients

BACKGROUND

Conceptual and methodological difficulties exist in assessing coping behaviors.

METHODS

This study investigated coping behaviors in 102 psychiatric outpatients. We used the Dissociative Experiences Scale, a 17-item posttraumatic stress disorder (PTSD) checklist; 2 measures of somatization (the Wahler Physical Symptom Inventory and the Physical Symptom Questionnaire), and 21 questions about subject involvement in positive and pathologic tension-reducing behaviors.

RESULTS

Preliminary data suggest that dissociative symptoms, PTSD-like symptoms, and somatization are associated with a variety of positive and pathologic tension-reducing behaviors.

CONCLUSIONS

The results suggest that psychiatric outpatients have an array of coping behavior: some are health-promoting, others are relatively self-destructive.

Physical symptoms, somatization, and dissociation in women survivors of childhood sexual assault

This study investigated the relation between history of sexual abuse, somatization, and dissociation in 53 women with a self-reported history of sexual assault in childhood and in 30 women who did not report such a history. Dissociation and reporting of chronic physical symptoms were positively correlated in subjects who had a history of sexual abuse, but this relation did not occur in subjects who reported no history of sexual abuse. The more perpetrators a subject reported, the greater the number of reported chronic physical symptoms. As the age of onset of abuse neared puberty, the more the subjects reported childbirth complications. The relation between somatization and dissociation is discussed.

Evaluation of human immunodeficiency virus (HIV) type 1 RNA levels in cerebrospinal fluid and viral resistance to zidovudine in children with HIV encephalopathy

The amount of human immunodeficiency virus (HIV) type 1 RNA and the presence of a codon 215 mutation indicative of zidovudine resistance were evaluated in cerebrospinal fluid (CSF) and plasma obtained from HIV-1-infected children. The level of HIV-1 RNA in CSF was highest in children with severe encephalopathy (n = 25; median, 430 copies/mL; range, 0-2.2 x 10(5) copies/mL) followed by the moderately encephalopathic (n = 7; median, 330; range, 0-1130) and nonencephalopathic groups (n = 9; median, 0; range, 0-566) (P = .007). There was no correlation between CSF and plasma HIV-1 RNA levels. Five of 7 children with the codon 215 mutation in CSF had a progression of encephalopathy, while all 8 children with wild type codon 215 had improved or stable disease during zidovudine treatment (P = .007). These findings suggest that increased viral replication and emergence of drug-resistant HIV-1 variants within the central nervous system may play a role in progression of HIV encephalopathy.

Comparison of virus burden in blood and sequential lymph node biopsy specimens from children infected with human immunodeficiency virus

BACKGROUND

Lymph nodes serve as reservoirs for the replication of human immunodeficiency virus (HIV) type 1. Comparison of serial measurements of virus burden in lymph nodes and peripheral blood after a change in antiretroviral therapy may provide insights into pathogenic mechanisms and permit a more accurate assessment of a therapeutic response.

STUDY DESIGN

Nevirapine was added to the drug regiment of eight children with HIV infection treated with the combination of zidovudine and didanosine who had increasing levels of serum p24 antigen. Lymph node biopsies were performed at entry and after 12 weeks of therapy.

RESULTS

Neither CD4 counts nor p24 antigen level correlated with the degree of viremia as measured by ribonucleic acid copy numbers in plasma. Correlations were found between HIV DNA copy number in peripheral blood mononuclear cells and HIV DNA copy number in lymph nodes (p = 0.02), as well as between peripheral blood CD4 counts and lymph node architecture. The HIV signals in the lymph nodes conformed to the anatomic organization of apical light zones in the germinal centers; however, in more advanced disease stages, organized germinal centers disappeared as evidence by a decline in the extent of the follicular dendritic network.

CONCLUSIONS

Lymph node biopsies in this small number of HIV-infected children revealed a progressive loss of an organized architecture, especially of the follicular dendritic network. This correlated with a progressive loss of CD4+ cells but not with other measures of disease stage, including viral load, as measured by ribonucleic acid copy numbers.

Lamivudine in children with human immunodeficiency virus infection: a phase I/II study. The National Cancer Institute Pediatric Branch-Human Immunodeficiency Virus Working Group

The safety, tolerability, pharmacokinetic profile, and preliminary activity of lamivudine (2'-deoxy-3'-thiacytidine), a novel cytidine nucleoside analogue with antiretroviral activity, in human immunodeficiency virus (HIV)-infected children beyond the neonatal period were studied. Ninety children received dosages of 1-20 mg/kg/day. Pharmacokinetic evaluation demonstrated serum and cerebrospinal fluid concentrations that increased proportionally to dose. As of January 1994, 11 children had been withdrawn from study for disease progression and 10 because of possible lamivudine-related toxicity, and 6 had died. CD4 and CD8 cell counts remained stable over 24 weeks in therapy-naive children and decrease slightly in previously treated children. Quantitative immune complex-dissociated p24 antigen and HIV RNA were decreased significantly at 12 and 24 weeks. In vitro resistance to lamivudine was documented in sequential virus isolates from some patients by 12 weeks. Lamivudine was well-tolerated and exhibited virologic activity in children, although future use in children is likely to be in combination antiretroviral regimens.

Dissociation in an outpatient sample of women reporting childhood sexual abuse

Researchers are providing evidence for the presence of dissociative symptoms in patients with histories of childhood sexual abuse. A total of 53 outpatient women who reported sexual abuse in childhood were interviewed and compared with 30 outpatient controls who reported no abuse. Controlling for the effect of physical abuse or maltreatment unrelated to sexual abuse, significant differences in mean scores were found on the Dissociative Experiences Scale. The effect of physical abuse or maltreatment on dissociation scores was not significant but may have been sensitive to the size of the sample.

Pharmacokinetic evaluation of the combination of zidovudine and didanosine in children with human immunodeficiency virus infection

As part of a phase I/II trial in children infected with human immunodeficiency virus, we studied the pharmacokinetics of zidovudine and didanosine administered as single agents and in combination. Zidovudine (60 to 180 mg/m2 per dose) was given orally every 6 hours, and didanosine (60 to 180 mg/m2 per dose) every 12 hours. Pharmacokinetic samples were obtained from 54 patients and the area under the plasma concentration-time curve (AUC) was estimated by means of a previously defined limited sampling strategy. Follow-up blood samples were obtained after 4 and 12 weeks of treatment. The mean AUC for zidovudine ranged from 4.8 mumol.hr per liter at 60 mg/m2 to 11.0 mumol.hr per liter at the 180 mg/m2 level, and increased in proportion to the dose. The mean AUC for didanosine ranged from 2.8 mumol.hr per liter (60 mg/m2) to 8.0 mumol.hr per liter (180 mg/m2), with a wide interpatient variability. The AUCs of zidovudine and didanosine remained unchanged when the agents were administered in combination. There was no significant change in the AUCs of either drug after 4 and 12 weeks in comparison with those on day 3 of therapy. However, there was greater interpatient and intrapatient variability with didanosine than with zidovudine. These observations have implications for the future utility of therapeutic drug monitoring with these agents.

Zidovudine and didanosine combination therapy in children with human immunodeficiency virus infection

OBJECTIVE

Zidovudine and didanosine are both beneficial for the treatment of human immunodeficiency virus (HIV) infection in children. Because disease progression and toxicity often limit their long-term use as single agents, new approaches to using nucleoside analogues are necessary to improve current antiretroviral therapy.

DESIGN

We conducted a phase I-II study to evaluate the tolerance, pharmacokinetics, and antiviral activity of the combination of zidovudine and didanosine in children with HIV infection. Sixty-eight children who were either previously untreated or who had manifested hematologic toxicity on full-dose zidovudine were enrolled. Eight dose combinations were studied in the previously untreated children, with doses of zidovudine ranging from 90 to 180 mg/m2 every 6 hours and doses of didanosine ranging from 90 to 180 mg/m2 every 12 hours.

RESULTS

Fifty-four previously untreated HIV-infected children were enrolled in this part of the study, of whom 49 remained in the study for a minimum of 24 weeks. For children with previous zidovudine-related hematologic toxicity, three dose levels with zidovudine at 60 mg/m2 every 6 hours orally and didanosine ranging from 90 to 180 mg/m2 every 12 hours orally were used. A total of 14 children were enrolled in this part of the study, and 12 remained on therapy for at least 24 weeks. No evidence of new or enhanced toxicity was observed in either group. After 24 weeks, the median CD4 cell count for all patients increased from 331 to 556 cells/mm3 (P = .01). For the previously untreated group, the median increase in CD4 counts was from 386 to 726 cells/mm3 (P = .003). The median p24 antigen concentration (in those with a detectable level at baseline) decreased from 95 to < 31 pg/mL (p < .001). The geometric mean titer of HIV in plasma decreased from 83.1 to 2.7 tissue culture infectious doses/mL (P = .001).

CONCLUSIONS

The combination of zidovudine and didanosine was well-tolerated at doses as high as those used in single agent therapy. Potent in vivo antiviral activity was observed. Combination therapy with nucleoside analogues may be an important approach to optimizing the use of these agents in the treatment of HIV infection.

Long-term outcome of children after intensive care

To determine the long-term outcome of children admitted to a pediatric ICU (PICU), we studied 976 consecutive patients admitted to our PICU in the 12 months ending June 30, 1983, and evaluated their outcome 30 to 36 months after PICU admission. There was no relationship between duration of PICU admission and outcome. Young children were more likely to die than older children, but young children who survived did not have an increased risk of handicap. Of the 974 children available for follow-up, 20% died, 5% had a severe handicap, 2% had a moderate handicap, 12% had a mild handicap, 17% were functionally normal but required medical supervision, and 42% were normal. Thus, 80% of the children survived 30 months or more, and 91% of the survivors will probably lead an independent life.

Chloroplast gene for Mr 32000 polypeptide of photosystem II in Euglena gracilis is interrupted by four introns with conserved boundary sequences

The gene for the Mr 32000 herbicide binding polypeptide of photosystem II has previously been mapped to the 5 kbp EcoRI fragment Eco I of Euglena gracilis chloroplast DNA. The nucleotide sequence of 3324 bp of Eco I, containing the psbA locus, has been determined. This locus encodes a polypeptide of 345 amino acids which is co-linear with, and has 86% derived amino acid sequence homology to sequences derived from four higher plants chloroplast psbA loci. The Euglena psbA gene contains four introns of size 435, 443, 434, and 617 bp. The four introns have conserved boundary sequences of the type previously described in the Euglena chloroplast gene (rbcL) for the large subunit of ribulose-1,5-bisphosphate carboxylase (Koller et al., Cell 36, 545-553, 1984).

Randomized prospective evaluation of cimetidine and antacid control of gastric pH in the critically ill

One hundred forty-four critically ill patients admitted to an intensive care setting were randomly assigned to cimetidine or antacid treatament groups. Gastric pH was monitored hourly. One hundred twenty-three (85%) patients demonstrated a fall in pH to less than 4 and were considered to require prophylaxis. Prophylaxis was considered adequate if the measured pH could then be maintained at greater than or equal to 4. Fifty-eight patients received antacids alone, the average requirement being 41 cc/hour. Sixty-five patients received cimetidine. Seventeen (26%) of the cimetidine prophylaxis patients failed to raise their pH and were than placed on hourly administration of antacid with successful elevations of pH to greater than or equal to 4 in all cases on an average supplementary dose of 53 cc/hour. Risk factors, including sepsis, hypotension, head injury, respiratory failure, degree of trauma, and age, were not statistically different in the two treated groups. Using these same criteria, responders to cimetidine could not be differentiated from nonresponders. All patients were protected from significant stress bleeding while on this study. Significant complications of either treatment were minimal. Antacids offered consistent protection against gastric acidity and were 100% effective. A routine schedule of 300 mg every six hours of cimetidine was effective in only 47% of patients, and the maximum dose of cimetidine was effective in only 74% of patients. Hourly measurement of intragastric pH is required for monitoring the response to prophylaxis of stress bleeding in severely ill patients.