Home visitation programs for at-risk young families. A systematic literature review.

BACKGROUND: This systematic literature review is stimulated by the perceived need of investigator, practice and policy stakeholders for a complete but parsimonious summary of key elements of programs that use home visitation for at-risk young families as the major delivery method. OBJECTIVES: To describe the program components, practices, outcomes, and reliability of the evaluation approaches. METHODS: Computer and hand searches of literature were carried out. Reports of established programs, from the last five years, that describe home visitation services to at-risk families were included. A comprehensive data collection tool was used in the analysis of the findings. FINDINGS: Improvements over the previous five years were seen in the following areas: use of early intervention model, inclusion of comparison groups and adequate sampling. DISCUSSION: Challenges remain in development, targeting and reporting of home visitation practice, overall lack of impact, differential effects by program site, retention of participants and appropriate measurement.

Respite care users who have children with chronic conditions: are they getting a break?

Caregiving for children with chronic illness and disabilities by family caregivers at home is widely recognized as an optimal choice for the child and family. To promote and maintain the health of the child, primary caregiver, and entire family, respite care has been established as an important caregiving resource. The purpose of this study was to describe primary caregivers' respite service use, perceptions of actual respite, and barriers to respite and respite care. A descriptive design with written survey methods and convenience sampling techniques was used. We found that, despite accessing a variety of respite services, the participants perceived limited actual respite from caregiving. Increased preparation of respite care providers and revision of available services may be means for achieving respite for primary caregivers and their families.

Seroprevalence of hepatitis C virus in the general population of northwest Tanzania.

Sera from 516 participants enrolled in a population-based cross-sectional study in northwest Tanzania were tested for antibodies to hepatitis C virus (HCV). The mean age of study subjects was 29 years (range = 16-49 years); 43% were men, 6% reported a history of blood transfusion, and 4% were infected with human immunodeficiency virus-1 (HIV-1). Although 53 of 516 sera (10.3%, 95% confidence interval [CI] = 7.8-13.2%) were repeatedly reactive by a third-generation enzyme immunoassay (EIA-3), only 6 of the 53 were positive when tested with a third-generation recombinant immunoblot assay (confirmed HCV seroprevalence = 1.2%, 95% CI = 0.4-2.5%). The positive predictive value of the HCV EIA-3 in this population was 18.8% (95% CI = 7.0-36.4%). False positivity was not correlated with EIA-3 optical density values, age, sex, infection with HIV-1, or a history of blood transfusion, but it was marginally associated with increased serum IgG levels. We conclude that the prevalence of HCV is low in this region and that the HCV EIA-3 has a higher false-positivity rate in this population than has been reported among U.S. blood donors.

Wild-type and mutant HIV type 1 nucleocapsid proteins increase the proportion of long cDNA transcripts by viral reverse transcriptase.

HIV-1 nucleocapsid, p7, contains two retroviral zinc fingers, which are both necessary for efficient packaging of genomic RNA and infectivity. The nucleocapsid protein is bound tightly to genomic RNA in the mature virion. In this study, the effect of p7 on polymerization of nascent cDNA by viral reverse transcriptase (RT) was examined. An 874-base RNA of HIV-1 was synthesized and used as a template in RT assays with varying concentrations of intact p7, mutants of p7 that have transposed or repeated zinc fingers, and several different peptides that represent various structural regions of p7. Results indicate that at greater than or equal to 50% saturation of p7-binding sites, with p7, there is up to a 90% reduction in total cDNA synthesis, as measured by nucleotide incorporation. However, the cDNA products that are made are almost exclusively full length. Three zinc finger mutants exhibited effects similar to those of wild-type p7. N-terminal and C-terminal halves of p7 inhibited total nucleotide incorporation, but also inhibited synthesis of long cDNA products by RT. In the absence of p7 an array of short transcripts (< 200 bases) was produced by RT. These studies show that full-length p7 is necessary to increase the proportion of long cDNA transcripts produced by RT. The relative position of the two zinc fingers is not critical for this effect.

The development of mothers' understanding of infant crying.

This study examines the development of mothers' understanding of their infants' crying. Semistructured tape-recorded interviews were conducted with 17 mothers at 6 weeks, 10 weeks, and 16 weeks postpartum. The mothers (9 primiparous, 8 multiparous) were chosen for their good health status and for their immediate support system. Two major themes were identified from the interviews. In general, it was found that as the mothers became more experienced, the understanding of the cry situation became more complete and soothing was more effective. The relation between crying and soothing became more differentiated, more cohesive, and more complete. The effect of experience on understanding was particularly dramatic in the case of multiparous mothers. Both health promotional and illness prevention programming are proposed as nursing care measures for mothers of crying infants. The important assumptions underlying each approach are delineated.

Human T cell lymphotropic virus types I and II in intravenous drug users in San Francisco: risk factors associated with seropositivity.

Serologic assays for human T cell lymphotropic virus types I and II (HTLV I/II) infection were done in 676 intravenous drug users (IVDUs) in San Francisco between 1985 and 1987: 150 in 1985, 44 in 1986, and 482 in 1987. All sera were tested by Western blot, ELISA, and p24 RIA. A total of 111 participants were seropositive in a minimum of two assays. Duration of intravenous heroin use was strongly associated with the risk of HTLV I/II seropositivity: greater than or equal to 21 years odds ratio, 6.1 (95% confidence interval [CI], 2.2-17.5), compared with less than 10 years of heroin use. Additional independent risk factors included black or Hispanic race, female sex, and the use of drugs in a shooting gallery. Coinfection of HTLV I/II and human immunodeficiency virus was less frequent than expected by chance (P less than .02). Longitudinal specimens were available in 154 participants. The age- and race-adjusted seroconversion rate was 3.4% (95% CI, 1.3-8.9) per person per year. Of the 349 homosexual men tested, none were HTLV I/II-seropositive.

C-terminal fragments of gp120 and synthetic peptides from five HTLV-III strains: prevalence of antibodies to the HTLV-III-MN isolate in infected individuals.

The immunoreactivity of HTLV-III-infected individuals and virus-inoculated chimpanzees with gp120 synthetic peptides of the HTLV-III gp120 envelope principle neutralizing domain (amino acid 301-324 sequences), derived from the HTLV-III isolates 3B, RF, MN, WMJ2, and SC were determined. Sequential bleeds from an infected lab worker and chimpanzees, both infected with the HTLV-IIIB, were immunoreactive only with the 3B peptide. In contrast, 33 HTLV-III-infected individuals were immunoreactive with the HTLV-III(MN) peptide. Of these 33 individuals, 23 were also immunoreactive with the HTLV-III(SC) peptide, and 18 with the HTLV-III(WMJ2) peptide. The data suggest that HTLV-III strains related to MN are most prevalent among HTLV-III-infected individuals. The binding specificities of goat sera generated against either of these synthetic peptides or the C-terminal fragment of gp120 (PB-1, amino acid 287-467, derived from the HTLV-III isolates 3B, RF, MN, WMJ2, and SC) were also determined. Four different ELISA formats (peptide sera/peptide antigens, peptide sera/PB-1 antigens, PB-1 sera/PB-1 antigens, and PB-1 sera/peptide antigens) were utilized to determine the cross-reactivity patterns of goat sera with the antigens. Goat sera generated against MN and SC sequences (PB-1 proteins, as well as synthetic peptides) were highly cross reactive. Thus, patient sera cross reactivity to multiple strains of the principal neutralizing domain may reflect the antigenic relatedness of the virus isolates rather than multiple infection events or strains generated during disease progression.

Experimental investigation of radiation from the interaction of an electron beam and a conducting grating.

Recent experimental results on the radiation generated from an electron beam passing closely over a conducting grating are presented. The most striking results are that the output power is 4 orders of magnitude more intense than that predicted by the Smith-Purcell explanation and that the output power increases exponentially with the beam thickness until it saturates at a thickness of a 1000 times the grating period. The recent theoretical model of Chang and McDaniel [Phys. Rev. Lett. 63, 1066 (1989); J. Opt. Soc. Am. B 7, 239 (1990)] is shown to compare favorably with these results.

Mother-to-infant transmission of human immunodeficiency virus type 1: association with prematurity or low anti-gp120.

In a prospective study of pregnant women infected with human immunodeficiency virus type 1 (HIV-1) in Brooklyn, New York, USA, 16 (29%) of 55 evaluable infants were infected with HIV-1. 9 infants had paediatric acquired immunodeficiency syndrome, 6 had less severe clinical manifestations of HIV-1 infection, and 1 was symptom-free but was seropositive for HIV-1 beyond 15 months of age. The 10 infants born at 37 weeks of gestation or earlier were at higher risk of HIV-1 infection than infants born at 38 weeks of gestation or later (60% vs 22%) but the median age at appearance of disease was approximately 5 months in both groups. The HIV-1 transmission rate was not associated with predelivery levels of maternal T cells, anti-p24, or neutralising antibodies but it was higher, among full-term infants, for those with mothers in the lowest third of the distribution of anti-gp120 levels (53%). On immunoblot, transmitting mothers lacked a gp120 band but not other bands. Protection was not associated with antibody to recombinant peptides from the hypervariable region of the major neutralising gp120 epitope, and the anti-gp120 endpoint dilution titre was similar in transmitting and non-transmitting mothers. Mothers of uninfected full-term infants appear to confer immunological protection against HIV-1 infection of their offspring by way of a high-affinity antibody to a gp120 epitope, whose specificity has importance for vaccine development and possibly perinatal immunotherapy.

A prospective study of human immunodeficiency virus type 1 infection and the development of AIDS in subjects with hemophilia.

We evaluated a multicenter cohort of 1219 subjects with hemophilia or related disorders prospectively, focusing on 319 subjects with documented dates of seroconversion to human immunodeficiency virus type 1 (HIV-1). The incidence rate of the acquired immunodeficiency syndrome (AIDS) after seroconversion was 2.67 per 100 person-years and was directly related to age (from 0.83 in persons 1 to 11 years old up to 5.66 in persons 35 to 70 years old; Ptrend = 0.00003). The annual incidence of AIDS ranged from zero during the first year after seroconversion to 7 percent during the eighth year, with eight-year cumulative rates (+/- SE) of 13.3 +/- 5.3 percent for ages 1 to 17, 26.8 +/- 6.4 percent for ages 18 to 34, and 43.7 +/- 16.4 percent for ages 35 to 70. Serial immunologic and virologic markers (total numbers of CD4 lymphocytes, presence of serum interferon or HIV-1 p24 antigen, and low or absent serum levels of anti-p24 or anti-gp120) predicted a high risk for the subsequent development of AIDS. Adults 35 to 70 years old had a higher incidence of low CD4 counts than younger subjects (P less than or equal to 0.005), whereas adolescents had a low rate of anti-p24 loss (P = 0.0007) and subjects 1 to 17 years old had a lower incidence of AIDS after loss of anti-p24 (P = 0.03). These findings not only demonstrate that the risk of AIDS is related directly to age but also suggest that older adults are disproportionately affected during the earlier phases of HIV disease, that adolescents may have a low replication rate of HIV, and that children and adolescents may tolerate severe immunodeficiency better because they have fewer other infections or because of some unmeasured, age-dependent cofactor or immune alteration in the later phase of HIV disease.

Predictive markers for the acquired immunodeficiency syndrome (AIDS) in hemophiliacs: persistence of p24 antigen and low T4 cell count.

STUDY OBJECTIVE: To investigate the predictive value of assays for human immunodeficiency virus (HIV) p24 antigen, p24 antibody, and gp120 antibody compared with T4 cell counts. DESIGN: Prospective cohort selected from persons who had HIV-antibody seroconversion. PATIENTS: Eighty-seven persons with hemophilia with an actuarial cumulative acquired immunodeficiency syndrome (AIDS) incidence of 26% (CI, 12% to 40%), 8 years after HIV-antibody seroconversion. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Human immunodeficiency virus p24 antigen was detected in 8 of 74 (11%) of the patients without AIDS and 7 of 13 (54%) of the patients with AIDS. The 2-year actuarial incidence of AIDS was 24% (CI, 0% to 48%) after detection of p24 antigen, 16% (CI, 0% to 34%) after loss of p24 antibody, 20% (CI, 0% to 45%) after loss of gp120 antibody, 31% (CI, 15% to 47%) after a T4 count of less than 200 cells/microL, and 67% (CI, 31% to 100%) after a T4 count of less than 200 cells/microL among those patients positive for p24 antigen. Very low numbers of T4 and T8 lymphocytes, presence of p24 antigen in serum, and absence of p24 antibody all had some predictive value. However, only p24 antigen (relative hazard 6.0, P = 0.008) and T4 counts (relative hazard 5.3, P = 0.002 with T4 count less than 200 cells/microL) independently predicted AIDS up to 12 months before diagnosis. CONCLUSIONS: Strong predictors of AIDS are p24 antigenemia or low T4 counts. Detection of p24 antigen is highly specific and complementary to the greater sensitivity of low T4 counts. These findings have important implications regarding prognosis, counseling, and the planning of clinical trials.

Magnetic resonance imaging in the diagnosis of temporal bone and skull base lesions.

Six patients are presented in whom total reliance on magnetic resonance imaging (MRI) interpretations would have resulted in less than ideal treatment. The misleading information on magnetic resonance imaging could be divided into two types; as follow: type I were those in which there was no signal but nonosseous pathology was present, and in type II an abnormal signal was present but misinterpreted. In three of these patients (cases, 2, 3, and 5), information gained from more traditional means (history, physical examination, audiologic and vestibular testing, and computed tomography) led to proper treatment, whereas, in two patients (cases 4 and 6), treatment exceeded that required by the disease process. In one patient (case 1), ideal therapy resulted, despite a negative magnetic resonance imaging study, when a small intracanalicular tumor was found fortuitously during a translabyrinthine vestibular nerve section for vertigo. Although magnetic resonance imaging provides excellent supplemental information to more traditional means of diagnosis, it cannot be used entirely in their place. As gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) becomes more readily available, as the resolution of magnetic resonance imaging improves, and as we gain more familiarity with this diagnostic modality, misleading information from these studies should decrease.

Molecular characterization and comparison of simian immunodeficiency virus isolates from macaques, mangabeys, and African green monkeys.

Simian immunodeficiency virus (SIV)/Mne has been inoculated into three species of macaques and into baboons. Virus was isolated from all the macaques who subsequently died at 15 to 120 weeks (mean 80 weeks) with various manifestations of immune deficiency. Individual animals varied in their viral antibody profile as a function of time after infection. Independent SIV isolates obtained from African green monkeys and magabeys were compared to SIV/Mne for their ability to replicate in lymphocytes and macrophages and with respect to the immunological relatedness of their viral proteins. Antibodies present in human immunodeficiency virus-2 (HIV-2)-infected individuals were readily detected by the virus produced by a single-cell clone of SIV/Mne.

Smith-Purcell radiation in the high conductivity and plasma frequency limits.

Radiation is calculated from currents produced by a nonrelativistic point charge that moves at a constant velocity above a conducting grating. Two different limits are considered. In the high conductivity limit, the surface charge is calculated from a nonretarded image charge, surface currents from the continuity equation, and the far field vector potential from the surface current. In the plasma frequency limit of the grating substrate a nonretarded electric potential is calculated from a two-region problem, bulk current from an interior potential, and the far field vector potential from the bulk current.

Human T lymphotropic virus type I antibody patterns: evidence of difference by age and risk group.

Detection of human T lymphotropic virus type I (HTLV-I) antibody was assessed on 368 sera from subjects with different clinical features and from different parts of the world. Enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay for purified p24 antibodies (p24-RIA) used as screening tests agreed in 88.7% of the sera. The results from 247 selected sera were compared with western blot (WB). WB was reactive in sera five to 25 times more dilute than the last positive ELISA or p24-RIA, but different WB batches varied in sensitivity. ELISA was more sensitive than p24-RIA, and p24-RIA was more specific than ELISA. Indeterminate WB interpretations were common (25.5%). Most seropositive intravenous drug abusers had unusually strong p24 bands by WB. Among healthy individuals, positive WB reactivity increased with age, whereas indeterminate reactivity declined (P = .034). Thus, more-sensitive and -specific HTLV-I antibody tests are needed.

A method for predicting individual HIV infection status in the absence of clinical information.

Latent structure analysis can be used to determine sensitivity and specificity rates of human immunodeficiency virus antibody assays in the absence of previous clinical or laboratory results. The technique was applied to the analysis of data obtained when a panel of serum samples, collected as part of a large-scale screening project, were subjected to four conventional bioassays (ag121, p24, gp120, and an enzyme-linked immunosorbent assay). To determine the accuracy of this statistical approach, the results of latent structure analysis were compared with the known clinical diagnoses of patients from whom the samples were taken, and nearly 100% agreement was obtained. Although a two-class latent structure model had some predictive value, a three-class model more adequately explained assay patterns. The use of the four standard assays in conjunction with the statistical methods described here would largely reduce the need for confirmatory Western blot assays in analyses of large panels of samples.

BK virus specific humoral and cell mediated immunity in allogeneic bone marrow transplant (BMT) recipients.

BKV specific humoral and cell mediated immunity was examined weekly in 19 allogeneic BMT recipients and correlated with the occurrence of BKV shedding. Responses to staphylococcal antigen (SPL) and tetanus toxoid (TET) were measured as specificity controls. Responses and virus shedding were assayed weekly for up to 15 weeks after BMT. Fourteen of 19 patients enrolled in this study were immunized with TET on the day of transplant. Significant rises in TET specific IgG were observed in TET immunized, but not in unimmunized, subjects. Similarly, TET specific lymphoproliferative responses were observed only in TET immunized subjects when they emerged from aplasia 3 to 4 weeks later. In contrast, all subjects had positive lymphoproliferative responses to SPL, an antigen derived from a ubiquitous agent All subjects were assayed weekly for the presence of BKV in the urine as detected by ELISA. By 15 weeks, 11 (58%) of these patients shed detectable quantities of BKV antigen at least once. Subjects who excreted BKV (BKV+) maintained BKV specific IgG at pretransplant levels, whereas levels steadily declined in those who did not (BKV-) (p less than 0.001). Lymphoproliferative responses to BKV, TET, and SPL antigens were not significantly different across time or between excretion groups. The temporal relationship of BKV shedding and the expression of BKV specific immunity was investigated by examining average responses measured in 5-week intervals surrounding positive and negative antigen detection assays. Both BKV specific IgG and BKV specific lymphoproliferative responses were higher (1.8 fold, p less than 0.005 and 2.5 fold, p = 0.06, respectively) surrounding positive detection assays. These findings indicate a strong association between BKV excretion and the development of indicators of virus specific immunity following BMT.

Cell-mediated immune responses to BK virus in normal individuals.

A lymphoproliferative assay was developed to study cell-mediated immunity (CMI) to BK virus (BKV), a human papovavirus, in healthy volunteer subjects. Responses to ultraviolet-inactivated antigen prepared from BKV-infected fibroblasts were compared to those elicited against a mock antigen preparation and an unrelated control antigen (tetanus toxoid, TET). CMI to BKV and TET were contrasted with humoral immunity as measured by enzyme-linked immunosorbent assay (ELISA). Specificity of the assay was confirmed by absence of response to mock antigen in all subjects studied. Positive response to BKV antigen was observed in all of 15 seropositive individuals but not in 5 neonates or 1 seronegative child. Similarly, all TET seropositive (n = 13) but no seronegative subjects (n = 2) responded to TET. The magnitude of lymphoproliferation to either antigen did not correlate with antibody titer. Additionally, the frequency of peripheral blood BKV-specific proliferating lymphocytes was determined by limiting dilution analysis (LDA). The frequency was approximately tenfold less than that observed for TET in the same group of subjects (1/30,300 vs 1/2,700). This may be due to differences in route and frequency of antigen exposure, both of which are unknown, at present, for BKV.