Understanding depression treatment and perinatal service preferences of Kenyan pregnant adolescents: A discrete choice experiment

BACKGROUND

Understanding mental health treatment preferences of adolescents and youth is particularly important for interventions to be acceptable and successful. Person-centered care mandates empowering individuals to take charge of their own health rather than being passive recipients of services.

METHODS

We conducted a discrete choice experiment to quantitatively measure adolescent treatment preferences for different care characteristics and explore tradeoffs between these. A total of 153 pregnant adolescents were recruited from two primary healthcare facilities in the informal urban settlement of Nairobi. We selected eight attributes of depression treatment option models drawn from literature review and previous qualitative work. Bayesian d-efficient design was used to identify main effects. A total of ten choice tasks were solicited per respondent. We evaluated mean preferences using mixed logit models to adjust for within subject correlation and account for unobserved heterogeneity.

RESULTS

Respondents showed a positive preference that caregivers be provided with information sheets, as opposed to co-participation with caregivers. With regards to treatment options, the respondents showed a positive preference for 8 sessions as compared to 4 sessions. With regards to intervention delivery agents, the respondents had a positive preference for facility nurses as compared to community health volunteers. In terms of support, the respondents showed positive preference for parenting skills as compared to peer support. Our respondents expressed negative preferences of ANC service combined with older mothers as compared to adolescent friendly services and of being offered refreshments alone. A positive preference was revealed for combined refreshments and travel allowance over travel allowance or refreshments alone. A number of these suggestions were about enhancing their experience of maternity clinical care experience.

CONCLUSION

This study highlights unique needs of this population. Pregnant adolescents' value responsive maternity and depression care services offered by nurses. Participants shared preference for longer psychotherapy sessions and their preference was to have adolescent centered maternal mental health and child health services within primary care.

Interpersonal Psychotherapy's problem areas as an organizing framework to understand depression and sexual and reproductive health needs of Kenyan pregnant and parenting adolescents: a qualitative study

BACKGROUND

Peripartum adolescents experience significant interpersonal transitions in their lives. Depression and emotional distress are often exacerbated by adolescents' responses to these interpersonal changes. Improved understanding of pregnancy-related social changes and maladaptive responses to these shifts may inform novel approaches to addressing the mental health needs of adolescents during the perinatal period. The paper aims to understand the sources of psychological distress in peripartum adolescents and map these to Interpersonal Psychotherapy's (IPT) problem areas as a framework to understand depression.

METHOD

We conducted interviews in two Nairobi primary care clinics with peripartum adolescents ages 16-18 years (n = 23) with experiences of depression, keeping interpersonal psychotherapy framework of problem areas in mind. We explored the nature of their distress, triggers, antecedents of distress associated with an unplanned pregnancy, quality of their relationships with their partner, parents, and other family members, perceived needs, and sources of support.

RESULTS

We found that the interpersonal psychotherapy (IPT) framework of interpersonal problems covering grief and loss, role transitions, interpersonal disputes, and social isolation was instrumental in conceptualizing adolescent depression, anxiety, and stress in the perinatal period.

CONCLUSION

Our interviews deepened understanding of peripartum adolescent mental health focusing on four IPT problem areas. The interpersonal framework yields meaningful information about adolescent depression and could help in identifying strategies for addressing their distress.

Prevalence and risk factors associated with depression in pregnant adolescents in Nairobi, Kenya

Background

Adolescent parenthood can be associated with a range of adverse outcomes for young mothers such as depression, substance abuse, and posttraumatic stress disorder. Identification of depression and understanding risk factors among pregnant adolescents is important for development of appropriate interventions and programs focused on adolescent mental health. This paper reports on the findings of the prevalence of depression and its associated risk factors among pregnant adolescents in Nairobi, Kenya.

Methods

We recruited 153 pregnant adolescent (14-18 years) who were accessing maternal health services in one of two Nairobi County primary health care facilities in the cross-sectional survey conducted in 2021. The Patient Health Questionnaire 9 was used to screen for depression. Multivariate Stepwise linear regression modelling was used to identify key predictors of depression.

Results

Using a cut off of 10 and above on PHQ-9, we found that 43.1% of the respondents were depressed. Depressive symptoms in were independently associated with being in school, experience of intimate partner violence, substance use within the family and having experienced pressure to use substances by family or peers.

Limitations

Cross-sectional by design and the applications of our findings are limited to settings that are similar to our study population. The PHQ-9 used has not been psychometrically validated locally in this sample.

Conclusion

We found a high prevalence of depressive symptoms among respondents. These risk factors identified merit further investigation. Comprehensive mental health screening needs to be integrated in primary and community health services on the possible presence of depression.

Human-centered design exploration with Kenyan health workers on proposed digital mental health screening and intervention training development: Thematic analysis of user preferences and needs

Background

Health providers' perceived sense of knowledge, competency, and self-efficacy to support the needs of their patients contributes to optimal patient health outcomes. With regards to mental health service delivery in Kenya, this area needs further exploration. Guided by the e-health technology acceptance mode, the needs and preferences of health care providers around mental health training for clinical management and their ability to intervene in peripartum adolescent mental health care are explored. We probed how well-equipped service providers are, their engagement with technology to learn and offer services. The health care provider's technology use preferences were also explored.

Method

Guided by a human-centered design-focused qualitative inquiry we interviewed 20 specialists around their needs, perspectives, and preferences for digitized mental health screening and intervention. Mean age was 44.2 years, (range of 32–58 years), 25% (5) males and 75% (15) females. After a written consenting process, the online interviews (30−45 min) were conducted in April 2021, once personal information was de-identified interviews were transcribed and coded. Thematic analysis was used and we combined rapid appraisal of Google Jamboard online storyboards to do individual human-centered design personas alongside.

Results

Our participants were well-exposed to digital technologies. Prohibitive costs of data bundles, lack of funds for consistent online engagement, high workload, and instability of access to appropriate gadgets were found to be barriers to e-health training. Emerging opportunities were well-identified adolescent mental health service and intervention needs, willingness to take online courses offered on learning platforms, and wish for these to be disseminated through diverse social media. Other recommendations were the need to have a user-friendly interface such as data-light engaging and practical materials including animations, short, group-based learning.

Conclusion

Understanding contextual factors that influence perceived usefulness and ease of use of the remote/digital components would be critical for e-training development and its uptake.

Impact of being an adolescent mother on subsequent maternal health, parenting, and child development in Kenyan low-income and high adversity informal settlement context

BACKGROUND

Women who have experienced adolescent pregnancy and early motherhood are disproportionately affected in terms of their health and parenting capabilities, as well as their offspring's health. Guided by Stress Process and Social Determinants of Health (SDH) Frameworks, which posit that multiple sources of stressors and structural determinants of adolescent pregnancy influence adolescent mothers' subsequent health and quality of parenting (Xavier et al 2018, McLoyd 1998, Conger et al 2010, Gipson et al 2008). These dynamics then further impact offspring's outcomes. Using an Integrated Stress-SDH Process for Health Disparities model and we test on whether early motherhood is associated with and subsequent maternal and child health from two informal settlements in Nairobi.

METHODS

A cross-sectional design with 394 mothers of 2-16 years old children who sought maternal and child health services at Kariobangi and Kangemi public health centers between October 2015 to April 2016 were recruited. Participating mothers were asked questions related to their adolescent pregnancy history, their current health, wellbeing, and parenting practices, and their child's health. Structural equation modeling (SEM) was utilized to examine hypothesized mediational pathways that adolescent pregnancy history has negative influences on women's health and parenting during adulthood, which also influence their child's health and development.

RESULTS

Our study supports that women with a history of adolescent motherhood have poor physical and mental health outcomes as adults after adjusting for demographic confounders. SEM results partially support the Stress-SDH Process model that history of adolescent pregnancy had negative consequences on women's adulthood health, which also negatively impacted offspring's physical and mental health.

CONCLUSION

Consistent with the Stress Process and SDH literature, we found consistent cross-cultural literature that adolescent pregnancy set the stage for, subsequent poor maternal health and child outcomes. Although history of adolescent pregnancy and motherhood was not necessarily associated with negative parenting, consistent with parenting literature, negative parenting was associated with poor child mental health. Findings suggest importance of providing integrated care that address health and parenting needs to optimize offspring's development in instances of early motherhood.

Mental Health Consequences for Healthcare Workers During the COVID-19 Pandemic: A Scoping Review to Draw Lessons for LMICs

Background: The COVID-19 pandemic has had a significant impact on the mental health of healthcare workers (HCWs) particularly in low and middle-income countries (LMICs). This scoping review provides a summary of current evidence on the mental health consequences of COVID on HCWs. Methods: A scoping review was conducted searching PubMed and Embase for articles relevant to mental health conditions among HCWs during COVID-19. Relevant articles were screened and extracted to summarize key outcomes and findings. Results: A total of fifty-one studies were included in this review. Depressive symptoms, anxiety symptoms, psychological trauma, insomnia and sleep quality, workplace burnout and fatigue, and distress were the main outcomes reviewed. Most studies found a high number of symptoms endorsed for depression, anxiety, and other conditions. We found differences in symptoms by sex, age, and HCW role, with female, younger-aged, frontline workers, and non-physician workers being affected more than other subgroups. Conclusion: This review highlights the existing burden of mental health conditions reported by HCWs during COVID-19. It also demonstrates emerging disparities among affected HCW subgroups. This scoping review emphasizes the importance of generating high quality evidence and developing informed interventions for HCW mental health with a focus on LMICs.

Mental Distress and Human Rights Violations During COVID-19: A Rapid Review of the Evidence Informing Rights, Mental Health Needs, and Public Policy Around Vulnerable Populations

Background: COVID-19 prevention and mitigation efforts were abrupt and challenging for most countries with the protracted lockdown straining socioeconomic activities. Marginalized groups and individuals are particularly vulnerable to adverse effects of the pandemic such as human rights abuses and violations which can lead to psychological distress. In this review, we focus on mental distress and disturbances that have emanated due to human rights restrictions and violations amidst the pandemic. We underscore how mental health is both directly impacted by the force of pandemic and by prevention and mitigation structures put in place to combat the disease. Methods: We conducted a review of relevant studies examining human rights violations in COVID-19 response, with a focus on vulnerable populations, and its association with mental health and psychological well-being. We searched PubMed and Embase databases for studies between December 2019 to July 2020. Three reviewers evaluated the eligibility criteria and extracted data. Results: Twenty-four studies were included in the systematic inquiry reporting on distress due to human rights violations. Unanimously, the studies found vulnerable populations to be at a high risk for mental distress. Limited mobility rights disproportionately harmed psychiatric patients, low-income individuals, and minorities who were at higher risk for self-harm and worsening mental health. Healthcare workers suffered negative mental health consequences due to stigma and lack of personal protective equipment and stigma. Other vulnerable groups such as the elderly, children, and refugees also experienced negative consequences. Conclusions: This review emphasizes the need to uphold human rights and address long term mental health needs of populations that have suffered disproportionately during the pandemic. Countries can embed a proactive psychosocial response to medical management as well as in existing prevention strategies. International human rights guidelines are useful in this direction but an emphasis should be placed on strengthening rights informed psychosocial response with specific strategies to enhance mental health in the long-term. We underscore that various fundamental human rights are interdependent and therefore undermining one leads to a poor impact on the others. We strongly recommend global efforts toward focusing both on minimizing fatalities, protecting human rights, and promoting long term mental well-being.

[Pedigree survey in a family with hereditary protein S deficiency]

Objective: To observe the clinical feature of familiar hereditary protein S deficiency(HPSD), and to explore the related gene mutations. Methods: A total of seven family members were enrolled in this study and examined during the June to September 2015. Medical histories of the families were analyzed to detect HPSD according to the diagnostic criteria. PROS1 genes of the proband and her family were analyzed. DNA was extracted from peripheral blood. The 15 exons and their intron-exon boundaries of PROS1 were amplified with PCR, and the PCR products were sequenced and analyzed to identify potential mutations. Medical histories from the family members died prior this study were also obtained. Results: Four out of 7 family members of 2 generations were diagnosed as HPSD. The proband suffered from pulmonary embolism, her elder brother suffered from cerebral infarction and her niece suffered from deep vein thrombosis. A missense mutation at the 1063 bp of cDNA(c.1063C>T)was detected in the exon 10 of PROS1, which resulted in arginine 355 to cysteine replacement in the first ball domain of laminin of the protein S(p.R355C). Conclusion: HPSD is an autosomal dominant genetic disease, patients often suffer from recurring vein thrombosis and pulmonary embolism. A missense mutation(c.1063C>T, p. R355C)of PROS1 was discovered in this Chinese family with HPSD, thus, this mutation might be the genetic basis responsible for these family members with HPSD .

Genetic characterization of red-colored heartwood genotypes of Chinese fir using simple sequence repeat (SSR) markers

The present study investigated the genetic characterization of red-colored heartwood Chinese fir [Cunninghamia lanceolata (Lamb.) Hook.] in Guangxi using 21 simple sequence repeat (SSR) markers and analyzes of the genetic variation (N = 149) in samples obtained from five sites in Guangxi Province, China. The number of different alleles and the Shannon's information index per locus ranged from 3 to 12 and from 0.398 to 2.258 with average values of 6 and 1.211, respectively, indicating moderate levels of genetic diversity within this germplasm collection. The observed and expected heterozygosity ranged from 0.199 to 0.827 and from 0.198 to 0.878 with an average of 0.562 and 0.584, respectively. Although, the mean fixation index was 0.044, indicative of a low level of genetic differentiation among germplasms, analysis of molecular variance revealed considerable differentiation (99%) within the samples. The neighbor-joining dendrogram revealed that the majority of red-colored Chinese fir genotypes were apparently not associated with their geographic origins. Further analysis by STRUCTURE showed that this Guangxi germplasm collection could be divided into three genetic groups comprising 76, 37, and 36 members, respectively; these were classified into mixed groups with no obvious population structure. These results were consistent with those of the cluster analysis. On the whole, our data provide a starting point for the management and conservation of the current Guangxi germplasm collection as well as for their efficient use in Chinese fir-breeding programs.

Thermal response of a dental tissue induced by femtosecond laser pulses

This paper reports a theoretical and experimental study for thermal transport in a thin slice of human tooth induced by a 120 fs, 800 nm pulse laser at a repetition rate of 1 kHz. The surface reflectivity of enamel and the convection heat transfer coefficient were determined using an inverse heat transfer analysis. Instead of a fully three-dimensional modeling, two simplified two-dimensional (2D) planar and axisymmetric heat conduction models were proposed to simulate the temperature fields. The temperature responses obtained from the 2D planar and axisymmetric model agree well with the experimental measurements. On the other hand, the one-dimensional (1D) result significantly differs from the 2D axisymmetric one, suggesting that care should be taken when a 1D thermal model is considered for estimating temperature response.

Enhancement of bacterial infections in mice by newcastle disease virus

This report describes an attempt to define the factors which incite secondary bacterial pneumonias. Groups of mice were given bacteria intraperitoneally and, at various intervals, Newcastle disease virus intravenously. There was an increase in the number of deaths and in the rates of death in these groups, when compared with a control group which was given only bacteria. These results were obtained with Streptococcus pneumoniae (Diplococcus pneumoniae), Pseudomonas aeruginosa, and Salmonella enteritidis ser. typhimurium. Newcastle disease virus increased the mortality rate of mice with bacterial infections when the two agents were given within 24 hr.

Metabolic Activity of the Trench Fever Rickettsia, Rickettsia quintana

A study of the metabolic activity of Rickettsia quintana was carried out by conventional Warburg and radioisotope techniques with intact cells harvested while growing in the fluid counterpart of the medium of Vinson and Fuller. Like other rickettsiae, R. quintana did not utilize glucose, but did metabolize glutamate and glutamine. Unlike typhus rickettsiae, R. quintana did not require a diluent high in K(+) for metabolic activity, and it utilized glutamine more efficiently than glutamate. In typical experiments, this microorganism produced 1.6 to 2.0 mumoles of CO(2) from glutamine per mg of rickettsial protein per hr at 37 C, while consuming 1.5 to 1.7 mumoles of O(2). R. quintana also utilized, in descending order, succinate, alpha-ketoglutarate, glutamate, pyruvate, and citrate; the first-named substrate was utilized more rapidly than glutamine. R. quintana, like typhus rickettsiae, has a glutamate-oxaloacetate transaminase because aspartate was isolated, by means of thin-layer chromatography, as one of the end products of the utilization of glutamine. When the microorganisms were incubated with glutamine-(14)C and unlabeled intermediates of the citric acid cycle, labeled dicarboxylic acids of the cycle were recovered. Labeled tricarboxylic acids, however, were not recovered, possibly because of cellular impermeability to the corresponding unlabeled intermediates. In the case of cis-aconitate, it was shown that this substrate interfered with the uptake of glutamine. These observations are believed to provide convincing evidence that glutamine is utilized through the citric acid cycle and that R. quintana, with the differences noted, resembles other rickettsiae.

Low-loss propagation in Cr4+:YAG double-clad crystal fiber fabricated by sapphire tube assisted CDLHPG technique

Cr4+:YAG double-clad crystal fiber with an uniform 10-microm core was fabricated by using a sapphire tube as a heat capacitor to stabilize the power fluctuation of the CO2 laser in the co-drawing laser-heated pedestal growth system. The uniformity of the fiber core showed a factor of 3 improvement compared to that without the use of sapphire tube. The variation of the core diameter is within the +/-1.35-degree adiabatic criterion and has a autocorrelation length of 1.7 mm. The measured propagation loss is only 0.02 dB/cm. The sapphire tube also reduces the vertical temperature gradient during the crystal fiber growth process so the 10-microm crystal core exhibits a smooth perimeter. The sapphire tube assisted system can be applied to the growth of many other optical crystal materials.

Double-clad Cr4+:YAG crystal fiber amplifier

A novel double-clad Cr4+:YAG crystal fiber is demonstrated by use of a codrawing laser-heated pedestal growth method. Up to 10 dB of gross gain at a wavelength of 1.52 microm is achieved at a pump power of 0.83 W, which, to our knowledge, is the first Cr4+-doped fiber amplifier in the optical fiber communication band.

Sharps injuries among hospital support personnel

Sharps injuries (SIs) among support personnel in hospitals have received little attention in the scientific literature. A cross-sectional study was undertaken to measure the incidence of SIs in Taiwanese support personnel. All support personnel, including laundry workers, cleaners, porters and central supply workers, from 16 hospitals were surveyed for SIs, sustained between June 1996 and July 1997. Either a questionnaire or face-to-face interviews, for those staff with a literacy problem, were used. Of the 862 persons eligible for study, 79.4% (684) were evaluable. Few staff (30.4%) had attended a prevention programme and 61% had suffered an SI in the past year. Few (25.4%) reported their injury. Hollow-bore needles, of which 72.2% had been used, were associated with 42.2% of injuries. Cleaners sustained the majority (65.7%) of injuries, and inappropriate disposal was associated with 54.7% of all injuries. For those staff employed for more than four years, the risk of sustaining an injury increased significantly with length of employment (P<0.001). Most of the injuries were sustained by cleaners handling sharps inappropriately disposed of by clinical staff. A safer environment for support staff could be achieved with the co-operation of clinical staff to correctly dispose of sharps to ensure single handling of sharps. A formal orientation of support staff in the reporting of SIs would enable clinical assessment and management of injuries, as well as an evaluation of needle and sharps safety in the healthcare setting.

Spontaneous femoral neck fracture complicating a healed subtrochanteric fracture--a case report

A rare case of spontaneous femoral neck fracture complicating a healed subtrochanteric fracture was encountered in an 85-year-old female. The subtrochanteric fracture was caused by a minor trauma with no other combined injury. Patient received close reduction and internal fixation two days later and the fracture healed in three months. Six months after operation, spontaneous ispilateral femoral neck fracture occurred without trauma. Although there were some reports about subcapital fracture or femur neck fracture complication after operation, this is the first case of spontaneous femoral neck fracture after healed subtrochanteric fracture which was treated with a 95 degrees dynamic condylar screw (DCS) and side plate previously without technical error.

Limited cutaneous systemic sclerosis: report of one case

We report a case of systemic sclerosis, limited type, in a 5 year old boy in Taiwan. He presented with erythema, tight skin over his face and digits, subcutaneous calcification, telangiectasis, as well as Raynaud's phenomenon. The laboratory data showed weakly positive antinuclear antibody (ANA), and Topoisomerase 1 antibody (anti-Scl-70) titers. However his esophagogram, CO diffusion capacity, as well as cardiac and renal function were all normal. He suffered from the skin change for 2 to 3 years before visiting our pediatric clinic when he was 7 years old. We gave him Dipyridamole, D-penicillamine, Colchicine, and Nifedipine. There was some remission of the scleroderma and Raynaud's phenomenon after our treatment.

Association of hypertriglyceridemia and insulin resistance in uremic patients undergoing CAPD

OBJECTIVE

Hyperlipidemia is frequently encountered in uremic patients and may be worsened by continuous ambulatory peritoneal dialysis (CAPD) treatment. The lipid abnormalities in these patients may be multifactorial. Insulin resistance (or its compensatory hyperinsulinemia) is commonly observed in uremic patients, but its association with hyperlipidemia in these patients has not been studied.

PATIENTS AND METHODS

Lipid profiles of 35 nondiabetic nonobese patients undergoing CAPD for more than 1 year (mean 52.3 months) were studied. Current laboratory data and parameters related to peritoneal dialysis (PD) within the previous 3 months were recorded. After overnight fasting and interruption of PD, an oral 75-g glucose tolerance test (OGTT) was examined.

RESULTS

After CAPD treatment for more than 12 months, these patients had higher serum triglyceride (TG) (p = 0.001) and total cholesterol (p = 0.0058) levels than their values before commencing CAPD. Twelve of 14 patients with serum TG higher than 200 mg/dL (high-TG) were diagnosed de novo, in contrast with only 1 patient diagnosed of de novo hypercholesterolemia (total cholesterol > 240 mg/dL). There was no difference in age, gender, body mass index (BMI), duration of PD treatment, serum albumin, hematocrit, intact serum parathyroid hormone (iPTH), peritoneal glucose load, solute transport, or weekly Kt/V urea between normal-TG and high-TG patients. After adjusting for age, gender, BMI, weekly Kt/V urea, and iPTH, the high-TG patients had higher levels of area under the curve for glucose (AUC(Glu)), area under the curve for insulin (AUC(Ins)), and AUC(Ins)/AUC(Glu) ratios (F = 10.63, 10.14, and 8.65; p = 0.0029, 0.0035, and 0.0065, respectively), indicating that the high-TG patients were more insulin resistant. There were 24 patients with normal glucose tolerance (NGT), and 11 patients with impaired glucose tolerance (IGT). The IGT group had higher serum TG (F = 10.43, p = 0.003) and total cholesterol (F = 8.05, p = 0.009) than the NGT group, after adjusting for BMI, duration of CAPD treatment, peritoneal glucose load, solute transport, serum albumin, and lipid levels before PD treatment. TheTG levels after CAPD treatment were positively correlated with AUC(Glu), AUC(Ins), and AUC(Ins)/AUC(Glu) ratio (r = 0.48, 0.53, and 0.49; p = 0.0037, 0.001, and 0.0028, respectively).

CONCLUSIONS

These results indicate that insulin resistance is an important factor in the development of hypertriglyceridemia in CAPD patients.

Ataxia telangiectasia: report of two cases

Ataxia telangiectasia (A-T) is a rare autosomal recessive multisystem disease. The diagnosis of A-T is based on the typical clinical picture: ataxia and telangiectasia. However, an increase in (alpha-fetoprotein (AFP) level and the identification of the A-T mutated gene (ATM) assist in an early diagnosis. Here we report two cases of A-T diagnosed in our hospital (case 1: a 7-year-old boy; case 2: an 8-year-old girl). Both of these patients had typical clinical pictures of ataxia and telangiectasia, AFP was also increased (case 1:471.2 ng/dL; case 2: 196 ng/dL). T-cell dysfunction was noted in both patients. Case 1 had IgG2 deficiency and case 2 had IgA, IgG2 and IgG3 deficiency. Case 2 developed malignant lymphoma at 9 years of age and died of pneumonia with respiratory failure at 10 years of age. Because of rhe rarity of A-T in Taiwan, we report two cases to help pediatricians make an early diagnosis of A-T if they have a patient with progressive ataxia and oculocutaneous telangiectasia.

Adversarial search by evolutionary computation

In this paper, we consider the problem of finding good next moves in two-player games. Traditional search algorithms, such as minimax and alpha-beta pruning, suffer great temporal and spatial expansion when exploring deeply into search trees to find better next moves. The evolution of genetic algorithms with the ability to find global or near global optima in limited time seems promising, but they are inept at finding compound optima, such as the minimax in a game-search tree. We thus propose a new genetic algorithm-based approach that can find a good next move by reserving the board evaluation values of new offspring in a partial game-search tree. Experiments show that solution accuracy and search speed are greatly improved by our algorithm.

Failure of the locking mechanism between the acetabular metal shell and the polyethylene liner after primary total hip arthroplasty--a case report

The short and intermediate-term clinical and radiographic results associated with Harris-Galante II porous-coated acetabular modular cup without cementing have been excellent in most patients. Nevertheless, its modular design introduced the potential for failure of the locking mechanism. There are four pairs of locking ties on the rim of metal shell to fix the polyethylene liner within it. Failure of any locking tine would result in less rigid fixation between the metal shell and the polyethylene liner and potentially produce instability or even disassembling of the liner. Only nine cases have been reported previously about the fractures of the locking tine, but it has never been reported in literature in Taiwan. We report a case with fracture of one tine following minor trauma at five years after primary total hip arthroplasty. During reoperation, scratching injury on the outer surface of the polyethylene liner in contact with the inferior tines of the metal shell was noted. Although no disassembling of the liner was noted, the remaining locking mechanism was found to be less rigid when the liner was taken out of the shell. The locking mechanism of HG II cup may be mechanically weak and may fail without major trauma; therefore, its design ought to be improved in an attempt to prevent postoperative dissociation of the polyethylene liner.

Comparison of antileukemic immunity against U937 cells in atopic asthmatics versus healthy controls

To assess the antitumor effects in atopic asthmatics versus healthy adults, we designed this study using in vitro mononuclear cells (MNC) culture as an immunity model with human leukemic U937 cells as the target. MNCs were collected from asthmatic subjects and healthy controls. Conditioned media from the MNC cultures (MNC-CM) were collected after stimulation with various concentrations of phytohemagglutinin (PHA). We treated U937 cells with these MNC-CMs, then assayed their proliferation and differentiation after 5 days of culture. At lower PHA doses (1.25 microg/ml), as well as in absence of PHA, the asthmatic MNC-CMs inhibited U937 cells growth to a slightly greater extent than did the MNC-CMs from controls. In contrast, when higher doses of PHA were used (5, 10 microg/ml), this growth-inhibiting effect was dramatically reversed. The dual effect of MNC-CM in these two groups was also shown in U937 cell differentiation assay, assessed as follows: morphological change by Liu's staining, functional change by NBT reduction test and CD 14 expression by flow cytometric detection. We suggest that the antileukemic effects of MNCs from asthmatic patients result from a slightly immunopotentiated status. This immunity may be dramatically reversed, however, after marked activation of MNCs.

Core decompression for osteonecrosis of the femoral head at pre-collapse stage

Twenty-five patients (27 hips) were retrospectively studied for core decompression in the treatment of osteonecrosis of the femoral heads at pre-collapse stage, Ficat and Alert stages I and II, from Apr. 1984 to Jun. 1998 with follow-up period at least 1 yr (mean 28 months). Eleven hips (10 patients) were considered to have failed due to progressive collapsed more than 2 mm, severe pain or reoperation. We further analyzed the results with regard to the stages, the size of the necrotic area according to the Ohzono classification, the lateral head index (LHI) and the Kerboul combined necrotic angle. The survival rate according to the Ohzono classification was type 1B: 100%, 1C: 44%, 2: 25%, and 3B: 0%. Hips with Kerboul angle less than 250 degrees revealed satisfactory results in all except one hip. All hips with Kerboul angle more than 250 degrees collapsed. Fourteen of the 15 hips (93%) with lateral head index more than 20% did not collapse and all hips except one (7/8) with LHI less than 12% collapsed. We conclude core decompression yields satisfactory results in osteonecrotic femoral heads at pre-collapse stage and with small necrotic area or good lateral buttress.

Experimental infection with bovine herpesvirus-4 enhances atherosclerotic process in rabbits

An association of herpesvirus and atherosclerosis has been suggested by seroepidemiologic studies and detection of the virus in arterial tissues. To facilitate the studies of the pathogenic role of herpesvirus in atherosclerosis, we established a rabbit model of atherosclerosis with bovine herpesvirus type-4 (BHV-4). Forty New Zealand White rabbits were randomly divided into six groups. Groups 1, 2, and 3 were inoculated iv with BHV-4 and control Groups 4, 5, and 6 with normal saline. Groups 1 and 4 were fed a regular diet throughout the experiment; Groups 2 and 5 were fed a diet supplemented with 2% cholesterol for 3 weeks starting at 3 weeks postinoculation; and Groups 3 and 6 with a diet supplemented with 2% cholesterol for 6 weeks starting at 3 days postinoculation. Extensive atherosclerotic lesions in Groups 2, 3, and 6, and small lesions in two rabbits in Group 1 were observed, but no obvious lesions were observed in Groups 4 and 5. BHV-4 DNA was demonstrated by polymerase chain reaction and liquid hybridization in aortic sections, various tissue samples, and peripheral blood mononuclear cells of all infected rabbits. Our studies demonstrated that BHV-4 can accelerate the atherosclerotic process in rabbits, and that experimental infection of rabbits with BHV-4 can be a useful atherosclerosis model.

Epidemiology of cervical and trochanteric fractures of the proximal femur in 1996 in Kaohsiung City, Taiwan

The goal of this study was to determine the incidence of cervical and trochanteric fractures of the proximal femur in 1996 in Kaohsiung City, Taiwan. Kaohsiung City is the industrial and commercial center of southern Taiwan, with a population of 1,433,621 in 1996. The number of individuals over 65 years of age accounted for 6.2% of the total population. Data from the archives of reimbursement of the National Health Insurance program were used to investigate the incidence of fractures of the proximal femur. This study detected 580 cervical and trochanteric fractures (40.5 fractures per 100,000 population per year) in 261 males (35.8 fractures per 100,000 men per year) and 319 females (45.3 fractures per 100,000 women per year), with 420 (72%) of these fractures occurring in individuals over 65 years of age. The age-specific incidences of cervical and trochanteric fractures increased exponentially with age in both genders. The overall ratio of cervical to trochanteric fractures was 1:1.04. The mean ages of women with cervical or trochanteric fractures (71.6 and 74.0 years, respectively) were significantly higher than those of males (59.9 and 64.8 years, respectively; P < 0.01). The age-adjusted incidences of fractures of the proximal femur in Kaohsiung City were higher than in other Asian countries, but were lower than in Western countries such as the United States and Norway. The urban lifestyle and low daily calcium intake may be responsible for this increased incidence of proximal femoral fractures in Kaohsiung City.

Hip arthroplasty for osteonecrosis in patients with systemic lupus erythematosus

Thirty-seven hip arthroplasties including 19 bipolar hemiarthroplasties (BH) and 18 total hip arthroplasties (THA) were performed in our hospital in 23 patients with systemic lupus erythematosus (SLE) for femoral head osteonecrosis between July 1984 and July 1996. These patients were followed up retrospectively to compare the results of BH and THA. One case with right side BH and left side THA expired about 1 year after operation and was excluded from this study. In both groups, these hips with pre-operative osteonecrosis were subclassified in Ficat and Arlet classification. The mean duration of follow-up was 44.5 months (24-85 months) for THA was 70.2 months (24-119 months) for BH. The mean Harris scores pre-operatively were 56.7 +/- 1.09 points in the BH group and 50.7 +/- 1.29 points in the THA group. The mean post-operative scores were 81.9 +/- 4.37 points in the BH group and 95.5 +/- 0.80 points in the THA group at final follow up. The clinical results of the THA group were better than those of the BH group. However, at an early stage before collapse of the femoral head (Ficat stage II), the results of BH were as good as those of THA. Five BH were converted to THA at the time ranging from 39 months to 113 months (mean 63.2 months) after primary operation due to acetabular cartilage wearing or severe groin pain. The failure rate of BH group was 27.8% (5/18). There was no loosening or revision in the THA group. Although the follow-up durations were different in these two groups, the clinical result was obviously superior in the THA group, particularly after the femoral heads had collapsed. Considering the relatively short life span of SLE patients, we prefer THA over BH in the treatment of the femoral head osteonecrosis in SLE patients. However, based on our results, BH is still a very good choice of treatment before the collapse of the femoral head.

Prevalence of nonreporting behavior of sharps injuries in Taiwanese health care workers

BACKGROUND

Health care workers (HCWs) were surveyed to identify factors associated with nonreporting behavior of sharps injuries (SIs) in Taiwan.

METHODS

We surveyed 10,469 full-time medical, nursing, technical, and supporting personnel employed at 16 randomly selected hospitals from 132 available accredited teaching hospitals in Taiwan. Information about the most recent injury and reporting behavior after an SI were collected from July 1996 to June 1997 by using a pretested structured questionnaire. Eleven categories, including an open-ended option, were provided for participants to explain their nonreporting behavior.

RESULTS

Questionnaires were completed by 82.6% (8645) of our sample, of whom 87.3% reported to have experienced a recent SI. A used item was the most commonly (P <. 001) involved item in an SI, and SIs with a used item were significantly more likely (odds ratio 3.6; CI 95%, 3.03-4.26; P <. 001) to be reported compared with an SI that involved unused items. A total of 81.8% of injuries were not reported, with job category significantly affecting reporting behavior (P <.001). Medical staff had the highest nonreporting rate (85.2%). Although attendees of a prevention program were statistically more likely (P <.001) to report an injury compared with nonattendees, the level of reporting in both groups was not encouraging (21.3% and 17.2%, respectively). All reasons given for nonreporting were disconcerting, but none more so than the use of subjective assessment of risk by 21.7% of HCWs who did not report their injuries. Other reasons for not reporting SIs included that the item was unused (34%) and that the HCW was too busy to report the SI (14.9%), unaware of reporting requirements (14. 4%), or immune to hepatitis B virus (12.4%).

CONCLUSIONS

With 82% of SIs in Taiwanese HCWs going unreported, the expected national incidence will be seriously underestimated and impact the appropriateness of prevention programs. The very low rate of reporting suggests that the current reporting system requires simplification. Because most injuries involved used items, the reporting systems also should include a more responsive management component. The results also suggest that the current prevention programs, currently provided by the general nursing department, require expert content knowledge in infection control if nonreporting and SIs are to be reduced.

Differential distribution of apolipoprotein E in young and aged spontaneously hypertensive and stroke-prone rats

OBJECTIVES

To evaluate whether the differential distribution of apolipoprotein E among lipoprotein fractions and hepatic expression of the apolipoprotein E gene are causal factors in the regulation of lipid metabolism and physiological functions in young and aged spontaneously hypertensive and stroke-prone rats.

DESIGN AND METHODS

Biochemical analyses were performed on serum and hepatic specimens from young (2-month-old) and aged (8-month-old) spontaneously hypertensive rats, stroke-prone spontaneously hypertensive rats and normotensive Wistar-Kyoto rats. Levels of apolipoprotein E among various lipoprotein fractions were determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Liver concentrations of apolipoprotein E mRNA were analyzed by Northern blotting and relative levels of apolipoprotein E mRNA in different strains of rats were compared. Statistical analysis was performed by measuring correlations between hepatic apolipoprotein E mRNA levels and biological parameters.

RESULTS

Levels of apolipoprotein E in high-density and low-density lipoproteins were significantly lower in hypertensive rats than in age-matched normotensive Wistar- Kyoto rats. Although there was a significant increase in high-density lipoprotein apolipoprotein E contents in all aged animals, the elevation in aged hypertensive rats was much less than that in aged normotensive rats. Levels of apolipoprotein E in the very-low-density lipoprotein fraction were diminished in young stroke-prone rats but were remarkably high in aged rats. Steady-state levels of apolipoprotein E mRNA increased with age in all strains of rats, whereas aged hypertensive rats exhibited lower apolipoprotein E mRNA levels than aged normotensive rats.

CONCLUSIONS

The distribution of apolipoprotein E among various lipoprotein fractions was dramatically altered with age, and the alteration varied among different strains of rats. The differential distribution of apolipoprotein E in young and aged spontaneously hypertensive and stroke-prone rats suggests that apolipoprotein E could be a causal factor that disturbs the homeostasis of lipids and lipoproteins and perturbs physiological functions in hypertensive rats.

Needlestick and sharps injuries among health-care workers in Taiwan

Sharps injuries are a major cause of transmission of hepatitis B and C viruses and human immunodeficiency virus in health-care workers. To determine the yearly incidence and causes of sharps injuries in health-care workers in Taiwan, we conducted a questionnaire survey in a total of 8645 health care workers, including physicians, nurses, laboratory technicians, and cleaners, from teaching hospitals of various sizes. The reported incidence of needlestick and other sharps injuries was 1.30 and 1.21 per person in the past 12 months, respectively. Of most recent episodes of needlestick/sharps injury, 52.0% were caused by ordinary syringe needles, usually in the patient units. The most frequently reported circumstances of needlestick were recapping of needles, and those of sharps injuries were opening of ampoules/vials. Of needles which stuck the health-care workers, 54.8% had been used in patients, 8.2% of whom were known to have hepatitis B or C, syphilis, or human immunodeficiency virus infection. Sharps injuries in health-care workers in Taiwan occur more frequently than generally thought and risks of contracting blood-borne infectious diseases as a result are very high.

Modified Mitchell osteotomy for hallux valgus

From 1988 to 1995, 96 patients (161 feet) underwent a modified Mitchell distal metatarsal osteotomy performed for mild-to-moderate hallux valgus. On AP x-rays of the standing foot, the average intermetatarsal angle was corrected from 15 degrees to 9 degrees, and the first metatarsophalangeal angles were corrected from an average of 41 degrees to 15 degrees. Criteria for evaluation of clinical results included relief of pain, appearance of foot, and shoe wear. After an average follow-up of 38 months, the overall satisfaction rate was 92.5%. Complications included 13 pin tract infections, two delayed unions, and two correction losses. The most common late sequela was transfer metatarsalgia of the lesser toes, which occurred in 20 feet (12.4%), leading to some dissatisfaction. The Mitchell osteotomy can be used on cases with less than 20 degrees of intermetatarsal angle, offering a stable construct with easy postoperative care.

Minocycline and cefotaxime in the treatment of experimental murine Vibrio vulnificus infection

We conducted an in vivo study with the mouse model of Vibrio vulnificus infection to evaluate the efficacies of therapy with minocycline or cefotaxime alone and in combination. V. vulnificus was introduced subcutaneously into the area over the right thigh. The inoculum size ranged from 1.0 x 10(3) to 1.2 x 10(8) CFU from experiment to experiment but was constant for all animals in the same experiment. Antibiotics were given intraperitoneally 2 h after the bacteria were inoculated. In experiments 1 to 4, the standard dose for humans was used to treat the infection, while in experiment 5, five times the standard dose for humans was used to treat the infection. In experiment 1, with a small inoculum of 5 x 10(3) CFU, all mice in the saline-treated control group and the cefotaxime-, minocycline-, and combined antibiotic-treated groups survived. In experiment 2, with a moderate inoculum of 1.2 x 10(5) CFU, all the mice in the three antibiotic-treated groups survived, while only two of nine mice in the control group survived. In experiment 3, with a large inoculum of 8.0 x 10(7) CFU, six of nine mice in the combined antibiotic-treated group survived, while only one of nine mice in the cefotaxime-treated group and none of the mice in the control and minocycline-treated groups survived. In experiment 4, with a large inoculum of 1.2 x 10(8) CFU, 8 of 20 mice in the combined antibiotic-treated group survived, while none of the 20 mice in the control group, the group treated with cefotaxime alone, and the group treated with minocycline alone survived. In experiment 5, in which mice were infected with a large inoculum of 6.6 x 10(7) CFU and treated with five times the standard human dose of antibiotics, 10 of 12 mice in the combined antibiotic-treated group survived, while only 4 of 12 mice in the minocycline-treated group, 1 of 12 mice in the cefotaxime-treated group, and none of the mice in the control group survived. In experiments 3 to 5, the difference in the survival rates between the combined antibiotic-treated and minocycline-treated groups was statistically significant (P < 0.05). These results indicate that combination therapy with cefotaxime and minocycline is distinctly more advantageous than therapy with the single antibiotic regimen for the treatment of severe experimental V. vulnificus infections.

In vitro synergism between cefotaxime and minocycline against Vibrio vulnificus

We conducted time-kill studies to evaluate the inhibitory activities of either cefotaxime or minocycline alone and the two drugs in combination against a clinical strain of Vibrio vulnificus. The MICs of cefotaxime and minocycline were 0.03 and 0.06 microg/ml, respectively. When approximately 5 x 10(5) CFU of V. vulnificus per ml was incubated with cefotaxime at 0.03 or 0.05 microg/ml, the bacterial growth was inhibited during the initial 2 and 8 h, respectively. Thereafter, V. vulnificus regrew and the level of growth reached that of the control. Within the dose range of less than five times the MIC, the duration of the inhibitory effect of cefotaxime was proportional to its concentration. When minocycline at 0.015, 0.03, 0.045, and 0.06 microg/ml was used to evaluate the inhibitory effect, a similar trend was observed. Either antibiotic at a concentration of five times the MIC or greater prevented the regrowth of V. vulnificus for at least 48 h. When cefotaxime at 0.05 microg/ml and minocycline at 0.045 microg/ml were combined in the same culture, the inhibitory effect against V. vulnificus persisted for more than 48 h, with no regrowth noted. The use of a combination of these two antibiotics resulted in the reduction of growth by 6 orders of magnitude compared to the use of either of the two antibiotics alone, and the number of surviving organisms in the presence of the antibiotics combined was approximately 3 orders of magnitude less than that in the starting inoculum. We conclude that cefotaxime and minocycline acted synergistically in inhibiting V. vulnificus in vitro.

Mouse skin damage caused by a recombinant extracellular metalloprotease from Vibrio vulnificus and by V. vulnificus infection

Vibrio vulnificus wound infection is characterized by an intense acute cellulitis which spreads along the subcutaneous tissue with severe tissue destruction. Toxins produced by the bacteria appear to be involved in the pathogenesis of skin necrosis and to facilitate microbial dissemination in vivo. We report microscopic studies of mouse skin damage caused by a single intradermal injection of V. vulnificus or of an extracellular metalloprotease isolated from this organism. The gene encoding this metalloprotease has been cloned and expressed in Escherichia coli. The crude metalloprotease extract obtained from the periplasmic fraction by osmotic shock was used in this study. Intradermal injection of this preparation resulted in marked edematous changes of the skin, which extended throughout the dermis and subcutaneous tissues and into adjacent muscles. The collagen and elastic fibers degenerated and some muscle cells even appeared necrotic. Blood vessels became congested, with moderate perivascular neutrophil and mononuclear cell infiltration. There was no evidence of necrotic changes in the blood vessel itself. These results show that the damage to the connective tissues caused by V. vulnificus is at least partly attributable to its protease. Therefore, the protease seems to be an important virulence factor of this microbe.

Natural killer activity in mice infected with Trypanosoma musculi

Trypanosoma musculi infection affected natural killer (NK) activity in mice. In the spleen, an increase of two to three times normal was displayed on days 2 to 4 after inoculation of parasites, followed by rapid decline to a subnormal level of activity that persisted for more than 3 weeks and included the phase of rapid parasite elimination. NK activity increased dramatically in peritoneal exudate and marrow early in infection, but the subsequent decline was more moderate than in the spleen. The subnormal splenic activity was not elevated by treating infected mice with an interferon inducer, polyinosinic acid-polycytidylic acid. Serum interferon levels were elevated early in infection, but by day 4 postinoculation, they had returned to undetectable. Injection of mice with antiserum to murine interferon-beta did not inhibit the early rise in NK activity or alter the course of trypanosome infection; in fact, the antiserum treatment enhanced splenic NK activity in infected mice. The early rise and subsequent decline of NK activity did not correlate with the course of T. musculi infection and subsequent cure. The cause of the dramatic decline in splenic NK activity is under investigation; it could result, for example, from arousal of suppressor cells, inhibition by prostaglandins, or inhibition by trypanosome-derived substances. Thus, NK cells may be prevented from fulfilling their potential of attacking the extracellular trypanosomes by the effects of inhibitory substances.

Thymosin peptides and lymphokines do not directly stimulate adrenal corticosteroid production in vitro

There is developing evidence that certain thymosin peptides and lymphokines produce a transient increase in steroid hormones when introduced systemically. Conversely, the repressive effect of adrenocortical steroids on the immune system is well documented. In the present study, the direct effect of certain components of the immune system on steroid output by rat adrenal fasciculata cells was tested. With this system, there was no direct steroidogenic effect of either the partially purified thymosin fraction 5, or any of the purified peptide components tested (thymosin alpha 1, alpha 7, or beta 4). These peptides also did not synergize the cellular response to ACTH, nor did they induce cAMP production by a ACTH- and NaF-responsive adrenal membrane preparation. Supernatants from Con A-stimulated spleen cells, which were demonstrated to contain lymphokine activity, and partially purified mouse interferon were also without a significant direct or synergistic effect on steroidogenesis by adrenocortical cells. These results suggest that the steroidogenic response to these peptides observed in vivo may be mediated by the central nervous system.

Thymosin peptides and lymphokines do not directly stimulate adrenal corticosteroid production in vitro

There is developing evidence that certain thymosin peptides and lymphokines produce a transient increase in steroid hormones when introduced systemically. Conversely, the repressive effect of adrenocortical steroids on the immune system is well documented. In the present study, the direct effect of certain components of the immune system on steroid output by rat adrenal fasciculata cells was tested. With this system, there was no direct steroidogenic effect of either the partially purified thymosin fraction 5, or any of the purified peptide components tested (thymosin alpha 1, alpha 7, or beta 4). These peptides also did not synergize the cellular response to ACTH, nor did they induce cAMP production by a ACTH- and NaF-responsive adrenal membrane preparation. Supernatants from Con A-stimulated spleen cells, which were demonstrated to contain lymphokine activity, and partially purified mouse interferon were also without a significant direct or synergistic effect on steroidogenesis by adrenocortical cells. These results suggest that the steroidogenic response to these peptides observed in vivo may be mediated by the central nervous system.

Augmentation of mouse natural killer activity and induction of interferon by tumor cells in vivo

Conventional and nude mice inoculated with syngeneic or allogenic tumor cells developed a rapid rise in serum interferon (IF) levels, peaking within 24 h. Within the same period, natural killer (NK) activity was readily boosted in the spleen. Both activities usually declined at 3 d. Cells that lacked the ability to augment NK activity also failed to induce detectable levels of IF. The boosting of IF and NK functions did not appear to be a result of contamination of the tumor lines by viruses because inoculation of several type C viruses into normal mice had no effect, and other viruses, like lymphocytic choriomeningitis virus and influenza, elevated IF and NK levels with a significantly later kinetics, peaking 3-4 d. The IF induced by tumor cells was heat and acid labile, species specific, and appeared to be in the type II class, although it was susceptible to antisera against Newcastle disease virus-induced IF. These data suggest that an early, nonthymus-dependent consequence of tumor-cell recognition is the production of IF, which, in turn, activates NK cells to lyse the tumor cells.

Immunity to virus-free syngeneic tumor cell transplantation in the BALB/c mouse after immunization with homologous tumor cells infected with type C virus

Syngeneic tumor cell lines free of endogenous type C virus or viral antigen antigen expression were derived from spontaneously occurring tumors of the BALB/cCr mouse. Two cell lines free of endogenous type C virus were examined and found to be highly tumorigenic in tumor growth kinetic studies. In vitro inoculation of these cell lines with Rauscher-murine leukemia virus (R-MuLV) resulted in their chronic infection in which 95 to 100% of the cells were scored as virus positive. These infected lines showed a highly significant increase in their immunogenicity as compared to their uninfected controls. Animals in which these virus-positive tumors regressed were then shown to be highly resistant to challenge with the uninfected tumor cell lines as well as to live R-MuLV. This observed resistance to uninfected tumor cell lines could not be induced by immunization of the mouse with uninfected tumor cells and R-MuLV simultaneously at the same injection site, nor could it be induced with lethally irradiated virus-infected tumor cells, subtumorigenic doses of uninfected cells, or inactivated R-MuLV or Gross leukemia virus (G-MuLV). Cell-mediated cytotoxicity studies revealed that spleen cells obtained from animals whose virus-infected tumors regressed were cytotoxic to homologous infected and uninfected tumor cells as well as to other uninfected tumor cell lines syngeneic to the BALB/c mouse. Correlation of in vitro cytotoxicity with in vivo immunity was provided by the Winn assay, by inoculation into susceptible mice of immune and nonimmune spleen cells premixed with uninfected tumor cells. The immune cells were highly effective in preventing this tumor cell transplantation. It was concluded that type-C virus infection of these syngeneic tumor cells resulted in their acquiring strong transplantation antigens that were in part due to the virion, but were at least in part due to alterations of antigens or haptens that are present in a less immunogenic form on the uninfected tumor cell.

Interferon preparations enhance phagocytosis in vivo

Previous studies have shown that interferon (IF) preparations enhance phagocytic activity in cultured mouse peritoneal macrophages. It is shown here that cell culture fluids containing large amounts of IF, which had been treated with acid and clarified of the inducer, Newcastle disease virus, enhanced phagocytic activity when injected into mice. Enhanced phagocytic activity also was observed after injection of Newcastle disease virus into mice, but the contribution of IF to this event was unclear. The kinetics of the phagocytic response to inducers in vivo were biphasic. Depression of phagocytosis occurred around 16 to 18 h after injection of Newcastle disease virus. The observed enhancement began about 12 h later and lasted for at least 60 h more. It was concluded that the complexity of the response of mice to an inducer makes analysis of the role of IF in the ensuing events difficult. However, because of documented phagocytosis-enhancing effects of IF in vitro, it is very likely that the in vivo effects observed here are to some degree mediated by IF. On this basis, the concept of the activity of IF as a lymphokine is potentially expanded.

Neutralization of the phagocytosis-enhancing activity of interferon preparations by anti-interferon serum

A wide variety of distinctive mouse interferon (IF)-containing preparations consistently exhibited the phagocytosis-enhancing activity reported previously. The enhancing as well as the antiviral activity of IF preparations were neutralized by a highly specific anti-IF serum.

Enhancement of phagocytosis by interferon-containing preparations

Exposure of mononuclear cells from the mouse peritoneal cavity to interferon (IF)-containing mouse sera enhanced phagocytosis of colloidal carbon particles by the cells. The same effect was observed when the cells were exposed to IF-containing cell culture harvest free of serum. The magnitude of this effect of IF-containing preparations paralleled the titer of IF and was not related to the dilution of various IF-containing serum specimens tested. The factor responsible for the enhancing effect was stable at pH 2, inactivated by trypsin, and nonsedimentable at 105,000 x g. Heating at 60 C for 1 hr destroyed it, and its kinetics of heat inactivation paralleled that of the antiviral activity of IF. A period of incubation of phagocytic cells with IF-containing serum was necessary before a maximum level of enhancement was reached, and once established was not removable by repeated washing of cells. The kinetics of the production of the enhancing factor in mice injected with Newcastle disease virus was essentially identical to that of the simultaneous production of IF as measured by antiviral activity. Contrary to the effect of mouse IF preparations, human IF preparation did not enhance the activity of mouse phagocytes. It appears, therefore, that the phagocytosis-enhancing factor falls within the present definition of IF.

Enhancement of the lethal effects of endotoxins by interferon inducers

Prior treatment of mice with poly I:C or NDV enhanced the lethal effect of E. coli or B. dermatitidis endotoxins.