Osteosarcoma of the jaw

The records of 66 patients with osteosarcoma of the jaw were reviewed. The ages of the 42 males and 24 females ranged from 12 to 79 years (mean, 34.2 years). Swelling and pain, the most frequent presenting complaints, were noted an average of three months before the patient was seen by a physician. Fifty-one percent of the lesions involved the maxilla and 49% involved the mandible. The most common sites of involvement were the body of the mandible and the alveolar ridge of the maxilla. Radiologically, most of the lesions in the maxilla were osteoblastic (50%), whereas most of those in the mandible were osteolytic (43%). Chondroblastic osteosarcoma was the most frequent histologic type (48%) and was associated with the best survival rate (47%). Treatment included radical and local surgery with radiotherapy, chemotherapy, or various combinations. The recurrence rate for all treatment modalities was 70%. Patients treated by initial radical surgery had the best survival (80%). Survival decreased to 27% with local surgery. Of the 43 (65%) patients who died, most died with uncontrolled local disease; only four patients had documented distant metastasis, which involved lung, cervical lymph nodes, spinal column, and brain.

Widespread silent transmission of pertussis in families: antibody correlates of infection and symptomatology

Four children with pertussis and their 18 family members were subjects of a 1-year study to detect infection and antibody responses to Bordetella pertussis. Attack rate for pertussis infection in contacts was 83%. Two-thirds of cases in these immunized contacts were subclinical. All infected family contacts had diagnostically elevated serologic tests for pertussis at the time the index case was diagnosed. Culture identified only 20% of infected contacts. Infected individuals had a mean of 5.5 of 10 antibody tests diagnostic for recent infection. ELISA assay for IgG to pertussis toxin and assay for IgA to filamentous hemagglutinin on serum and nasal secretions were the most discriminating diagnostic tests. Index cases and immunized contacts had different type and timing of antibody responses, making a single assay or sampling unable to identify all infected individuals. Symptomatic infection was characterized by higher magnitude of pertussis toxin antibody response and asymptomatic infection by filamentous hemagglutinin. After pertussis immunization, immunity to disease is greater than is protection from infection.

Laser midline glossectomy as a treatment for obstructive sleep apnea

Multiple site specific procedures have been proposed to treat obstructive sleep apnea syndrome (OSAS). Midline glossectomy (MLG) is a procedure that directly enlarges the hypopharyngeal airspace using the carbon dioxide laser. The initial experience of 12 patients is presented. Midline glossectomy as the sole procedure was performed on 11 patients who had failed uvulopalatopharyngoplasty (UPPP) and who were felt to have significant hypopharyngeal collapse on physical examination and Müller's maneuver. One patient with primary hypopharyngeal narrowing underwent MLG. Five (42%) were considered responders with Respiratory Disturbance Index (RDI) decreasing from 60.6 per hour to 14.5 per hour. In seven nonresponders, there was no significant change in the RDI (62.6 events per hour to 48.4 events per hour). Cephalometric analysis showed that responders tended to be more retrognathic (sella-nasion-supramentale (S-N-B = 74.4 degrees)) than nonresponders (S-N-B = 79.3 degrees). Responders were significantly less obese (body mass index (BMI = 30.6)) than nonresponders (BMI = 37.9). There were five minor complications including minor bleeding (n = 3), prolonged odynophagia (n = 1), and minor change in taste (n = 1). There were no major complications, and no persistent difficulties with speech or swallowing. These results demonstrate that direct surgical modification of the tongue base and associated structures can significantly impact obstructive apnea. Midline glossectomy or similar procedures may be useful in a subset of patients with OSAS.

Insulin biosynthesis in the rat: demonstration of two proinsulins

Proinsulin, a single-chain precursor of insulin, has been detected in biosynthetic studies in vitro,(1-4) and in crystalline preparations of insulin from several species.(1, 5-7) It appears that proinsulin normally serves neither as a major storage nor secretory form of the hormone.(8) Its primary functions seems to be to facilitate the efficient formation of the disulfide bonds of insulin.(9)Although several species of fish have two insulins differing slightly in primary structure,(10-12) the rat is the only mammal where this is known to be the case.(13, 14) As the two rat insulins are nonallelic(14) and presumably coded by two distinct genes, a separate proinsulin would be expected to precede each insulin. We have demonstrated the biosynthesis of both insulins(15) and of a proinsulin corresponding to each in isolated islets of Langerhans, and have detected probable intermediates in the conversion of these proinsulins to insulin. Labeled peptide material corresponding to the free connecting segment of proinsulin (C-peptide) was detected in insulin-containing fractions isolated from incubated rat islets. It was noted that islets incubated in vitro secreted small amounts of newly synthesized proinsulin as well as the two insulins and essentially equivalent amounts of C-peptide. Increasing the glucose content of the medium selectively enhanced the incorporation of radioactivity into proinsulin and insulin and also seemed to increase the relative proportion of labeled proinsulin appearing in the medium.

The spontaneous reoxidation of reduced beef and rat proinsulins

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Obesity following ART initiation is common and influenced by both traditional and HIV-/ART-specific risk factors

Background

Obesity rates are increasing among HIV-infected individuals, but risk factors for obesity development on ART remain unclear.

Objectives

In a cohort of HIV-infected adults in Rio de Janeiro, Brazil, we aimed to determine obesity rates before and after ART initiation and to analyse risk factors for obesity on ART.

Methods

We retrospectively analysed data from individuals initiating ART between 2000 and 2015. BMI was calculated at baseline (time of ART initiation). Participants who were non-obese at baseline and had ≥90 days of ART exposure were followed until the development of obesity or the end of follow-up. Obesity incidence rates were estimated using Poisson regression models and risk factors were assessed using Cox regression models.

Results

Of participants analysed at baseline (n = 1794), 61.3% were male, 48.3% were white and 7.9% were obese. Among participants followed longitudinally (n = 1567), 66.2% primarily used an NNRTI, 32.9% a PI and 0.9% an integrase strand transfer inhibitor (INSTI); 18.3% developed obesity and obesity incidence was 37.4 per 1000 person-years. In multivariable analysis, the greatest risk factor for developing obesity was the use of an INSTI as the primary ART core drug (adjusted HR 7.12, P < 0.0001); other risk factors included younger age, female sex, higher baseline BMI, lower baseline CD4+ T lymphocyte count, higher baseline HIV-1 RNA, hypertension and diabetes mellitus.

Conclusions

Obesity following ART initiation is frequent among HIV-infected adults. Key risk factors include female sex, HIV disease severity and INSTI use. Further research regarding the association between INSTIs and the development of obesity is needed.

Regulation of ornithine decarboxylase in 3T3 cells by putrescine and spermidine: indirect evidence for translational control

Addition of putrescine of spermidine prevents the increase in ornithine decarboxylase activity in cultures of 3T3 cells brought about by pituitary growth factors and results in a rapid, specific, and reversible reduction of enzyme activity in cultures previously stimulated by the growth factors. These effects are not due to polyamine toxicity and do not require other organic medium components. The amines apparently share a single carrier-mediated transport system in 3T3 cells. Methylglyoxal bis(guanylhydrazone), an inhibitor of spermidine synthesis from putrescine was found to also inhibit uptake of each amine. Studies with this drug indicate that each amine is effective without further metabolism. Since ornithine decarboxylase activity decays more rapidly in the presence of each polyamine after addition of camptothecin, the major locus of amine action appears to be in the cytoplasm. However, direct inhibition of the enzyme in vivo by assimilated amines appears to account for at most a small part of the reduction in activity, a conclusion supported by the inability to recover activity in vitro. Also, neither amine seems to act by accelerating enzyme inactivation. When amines are removed from the medium, the subsequent recovery of enzyme activity is totally prevented by trichodermin, an inhibitor of protein synthesis, but is only slightly reduced by camptothecin. It is suggested that both putrescine and spermidine reduce ornithine decarboxylase activity by selectively inhibiting translation.

Effective treatment of severe cancer pain of the head using low-dose ketamine in an opioid-tolerant patient

We report the case of a 39-year-old man with severe pain due to unresectable squamous-cell carcinoma of the maxillary sinus that had invaded cranial bone and had metastasized to the cervical spine. Tolerance to opioids had developed, and high doses of transdermal, continuous intravenous, and epidural opioids did not control his pain. An acute episode of extremely severe head pain was immediately controlled with a subanesthetic dose of ketamine after failure of a stress dose of corticosteroid and intravenous lidocaine. Because the patient was terminally ill and invasive procedures were not options, we controlled his pain using a low-dose ketamine infusion until his death 13 days later. Ketamine may be a good co-analgesic for breakthrough pain and for severe pain caused by terminal cancer when invasive techniques are inappropriate. Its mechanism of action may include reversal of opioid tolerance in addition to an inherent analgesic effect.

Modulation of invasive properties of murine squamous carcinoma cells by heterologous expression of cathepsin B and cystatin C

Murine SCC-VII squamous carcinoma cells have the capacity to penetrate reconstituted basement membranes (Matrigel) in vitro. The invasion of Matrigel layers by SCC-VII cells was significantly reduced by E-64, a specific inhibitor of lysosomal cysteine proteinases. The cathepsin-B-selective E-64 derivative, CA-074, inhibited penetration of Matrigel by SCC-VII cells to the same extent, indicating a major role for this particular lysosomal enzyme in extracellular-matrix degradation during squamous-carcinoma-cell invasion. SCC-VII cells were stably transfected with a cDNA encoding human procathepsin B, in an attempt to modulate the invasive properties of the cell line. The transfected cells expressed the heterologous gene, secreted increased amounts of procathepsin B and displayed enhanced invasive potential. In vivo, the activity of cathepsin B is strictly regulated by endogenous inhibitors. SCC-VII cells were therefore also stably transfected with a cDNA encoding human cystatin C, the most potent cysteine-proteinase inhibitor in mammalian tissues. The expression of this transgene resulted in the production of active recombinant cystatin C and a pronounced reduction in Matrigel invasion. These studies demonstrate that the invasive properties of squamous-cell carcinomas can be changed by modulation of the balance between cathepsin B and its endogenous inhibitors, and provide further evidence for the involvement of this lysosomal cysteine proteinase in tumour invasion and metastasis.

Baricitinib versus dexamethasone for adults hospitalised with COVID-19 (ACTT-4): a randomised, double-blind, double placebo-controlled trial

BACKGROUND

Baricitinib and dexamethasone have randomised trials supporting their use for the treatment of patients with COVID-19. We assessed the combination of baricitinib plus remdesivir versus dexamethasone plus remdesivir in preventing progression to mechanical ventilation or death in hospitalised patients with COVID-19.

METHODS

In this randomised, double-blind, double placebo-controlled trial, patients were enrolled at 67 trial sites in the USA (60 sites), South Korea (two sites), Mexico (two sites), Singapore (two sites), and Japan (one site). Hospitalised adults (≥18 years) with COVID-19 who required supplemental oxygen administered by low-flow (≤15 L/min), high-flow (>15 L/min), or non-invasive mechanical ventilation modalities who met the study eligibility criteria (male or non-pregnant female adults ≥18 years old with laboratory-confirmed SARS-CoV-2 infection) were enrolled in the study. Patients were randomly assigned (1:1) to receive either baricitinib, remdesivir, and placebo, or dexamethasone, remdesivir, and placebo using a permuted block design. Randomisation was stratified by study site and baseline ordinal score at enrolment. All patients received remdesivir (≤10 days) and either baricitinib (or matching oral placebo) for a maximum of 14 days or dexamethasone (or matching intravenous placebo) for a maximum of 10 days. The primary outcome was the difference in mechanical ventilation-free survival by day 29 between the two treatment groups in the modified intention-to-treat population. Safety analyses were done in the as-treated population, comprising all participants who received one dose of the study drug. The trial is registered with ClinicalTrials.gov, NCT04640168.

FINDINGS

Between Dec 1, 2020, and April 13, 2021, 1047 patients were assessed for eligibility. 1010 patients were enrolled and randomly assigned, 516 (51%) to baricitinib plus remdesivir plus placebo and 494 (49%) to dexamethasone plus remdesivir plus placebo. The mean age of the patients was 58·3 years (SD 14·0) and 590 (58%) of 1010 patients were male. 588 (58%) of 1010 patients were White, 188 (19%) were Black, 70 (7%) were Asian, and 18 (2%) were American Indian or Alaska Native. 347 (34%) of 1010 patients were Hispanic or Latino. Mechanical ventilation-free survival by day 29 was similar between the study groups (Kaplan-Meier estimates of 87·0% [95% CI 83·7 to 89·6] in the baricitinib plus remdesivir plus placebo group and 87·6% [84·2 to 90·3] in the dexamethasone plus remdesivir plus placebo group; risk difference 0·6 [95% CI -3·6 to 4·8]; p=0·91). The odds ratio for improved status in the dexamethasone plus remdesivir plus placebo group compared with the baricitinib plus remdesivir plus placebo group was 1·01 (95% CI 0·80 to 1·27). At least one adverse event occurred in 149 (30%) of 503 patients in the baricitinib plus remdesivir plus placebo group and 179 (37%) of 482 patients in the dexamethasone plus remdesivir plus placebo group (risk difference 7·5% [1·6 to 13·3]; p=0·014). 21 (4%) of 503 patients in the baricitinib plus remdesivir plus placebo group had at least one treatment-related adverse event versus 49 (10%) of 482 patients in the dexamethasone plus remdesivir plus placebo group (risk difference 6·0% [2·8 to 9·3]; p=0·00041). Severe or life-threatening grade 3 or 4 adverse events occurred in 143 (28%) of 503 patients in the baricitinib plus remdesivir plus placebo group and 174 (36%) of 482 patients in the dexamethasone plus remdesivir plus placebo group (risk difference 7·7% [1·8 to 13·4]; p=0·012).

INTERPRETATION

In hospitalised patients with COVID-19 requiring supplemental oxygen by low-flow, high-flow, or non-invasive ventilation, baricitinib plus remdesivir and dexamethasone plus remdesivir resulted in similar mechanical ventilation-free survival by day 29, but dexamethasone was associated with significantly more adverse events, treatment-related adverse events, and severe or life-threatening adverse events. A more individually tailored choice of immunomodulation now appears possible, where side-effect profile, ease of administration, cost, and patient comorbidities can all be considered.

FUNDING

National Institute of Allergy and Infectious Diseases.

Culturing selects for specific genotypes of Borrelia burgdorferi in an enzootic cycle in Colorado

In Colorado, Borrelia burgdorferi sensu stricto, the etiologic agent of Lyme disease, is maintained in an enzootic cycle between Ixodes spinipalpis ticks and Neotoma mexicana rats (27). The frequencies of flagellin (fla), 66-kDa protein (p66), and outer surface protein A (ospA) alleles were examined in 71 B. burgdorferi isolates from samples from Colorado. Approximately two-thirds of these samples were isolates from I. spinipalpis ticks that had been cultured in BSK-H medium prior to DNA extraction. The remaining samples were from total DNA extracted directly from infected I. spinipalpis ticks. A portion of each gene was amplified by PCR and screened for genetic variability by single-strand conformation polymorphism (SSCP) analysis. We identified three alleles in the fla gene, seven in the p66 gene, and seven in the ospA gene. Sequencing verified that the amplified products originated from B. burgdorferi template DNA and indicated 100% sensitivity and specificity of the SSCP analysis. The frequencies of the p66 and ospA alleles were significantly different between cultured and uncultured spirochetes. The number of three-locus genotypes and the genetic diversity of alleles at all loci were consistently lower in cultured spirochetes, suggesting that culturing of B. burgdorferi in BSK-H medium may select for specific genotypes.

Transgender Women Living with HIV Frequently Take Antiretroviral Therapy and/or Feminizing Hormone Therapy Differently Than Prescribed Due to Drug-Drug Interaction Concerns

PURPOSE

Both hormone therapy (HT) and antiretroviral therapy (ART) can be lifesaving for transgender women (TW) living with HIV, but each has side effects and potential drug-drug interactions (DDI). We assessed how concerns about HT-ART interactions affect treatment adherence.

METHODS

This study used a cross-sectional survey of TW (n = 87) in Los Angeles, CA.

RESULTS

Fifty-four percent were living with HIV; 64% used HT. Only 49% of TW living with HIV discussed ART-HT DDI with their provider; 40% reported not taking ART (12%), HT (12%), or both (16%) as directed due to DDI concerns.

CONCLUSION

Imperfect HT/ART use and limited provider communication suggests a need for improved HT-ART integration.

Problem drinking is associated with increased prevalence of sexual risk behaviors among men who have sex with men (MSM) in Lima, Peru

BACKGROUND

Alcohol use is an important but understudied HIV risk factor among men who have sex with men (MSM), particularly in Latin America. We studied the relationship between problem drinking and sexual risk among MSM in Lima, Peru.

METHODS

We recruited 718 participants from 24 neighborhoods for a study on sexually transmitted infections and community-building among MSM. Multivariate analysis was used to identify factors independently associated with problem drinking, which was defined via the CAGE Questionnaire.

RESULTS

Of 718 participants, 58% met criteria for problem drinking. In univariate analysis, problem drinkers were significantly more likely to report failing to always use condoms, use alcohol or drugs prior to their most recent sexual encounter, report a history of sexual coercion and to engage in transactional sex. Problem drinkers also reported significantly higher numbers of recent and lifetime sexual partners. In multivariate analysis, factors independently associated with problem drinking included a history of sexual coercion [OR 1.8 95%, CI 1.2-2.6], having consumed alcohol prior to the most recent sexual encounter [OR 2.1 95%, CI 1.5-2.9], receiving compensation for sex in the last six months [OR 1.6, 95% CI 1.1-2.2] or having reported a prior HIV+ test [OR 0.5, 95% CI 0.2-0.9].

DISCUSSION

We found a high prevalence of problem drinking among MSM in Lima, Peru, which was associated with increased sexual risk in our study. Of note, individuals who were already HIV-infected were less likely to be problem drinkers. Further studies and targeted interventions to reduce problem drinking among MSM are warranted.

A cross-sectional study of low HIV testing frequency and high-risk behaviour among men who have sex with men and transgender women in Lima, Peru

BACKGROUND

Increased HIV testing frequency among high-risk populations such as men who have sex with men (MSM) and male-to-female transgender women (TW) can lead to earlier treatment and potentially reduce HIV transmission.

METHODS

We analyzed baseline survey data from 718 high-risk, young (median age 29 [interquartile range 23-35]) MSM/TW enrolled in a community-based HIV prevention trial between 2008-2009. Participants were recruited from 24 neighborhoods in and around Lima, Peru. We assessed HIV testing frequency, testing behaviour, and motivations and barriers to testing. Multivariate analysis identified correlates to prior HIV testing.

RESULTS

Overall, 79.6% reported HIV testing within their lifetimes, however, only 6.2% reported an average of two tests per year, as per Peruvian Ministry of Health guidelines. The most commonly reported motivators for testing were to check one's health (23.3%), lack of condom use (19.7%), and availability of free testing (14.0%), while low self-perceived risk for HIV (46.9%), fear of a positive result (42.0%), and lack of access to testing services (35.7%) were the most frequently reported barriers. In multivariate analysis, factors independently associated with HIV testing included age [adjusted prevalence ratio (APR) 1.00, 95% CI (1.00-1.01)], transgender-identification vs. gay-identification [APR 1.11, 95% CI (1.03-1.20)], history of transactional sex [APR 1.16, 95% CI (1.07-1.27)], and prior sexually transmitted infection diagnosis [APR 1.15, 95% CI (1.07-1.24)].

CONCLUSIONS

An overwhelming majority of participants did not meet the standard-of-care for testing frequency. The reported motivations and barriers to testing highlight issues of risk perception and accessibility. Our findings suggest utilizing non-traditional outreach methods and promoting HIV testing as a routine part of healthcare in Peru to encourage testing and knowledge of HIV serostatus.

Social isolation and connectedness as determinants of well-being: Global evidence mapping focused on LGBTQ youth

Social isolation describes a lack of a sense of belonging, the inability to engage and connect with others, and the neglect or deterioration of social relationships. This conceptual review describes how social isolation and connectedness affect the well-being of LGBTQ youth. Most studies focused on the psychosocial experience of social isolation, which led to suicide attempt, self-harm, sexual risk, and substance use. Scholarly work has drawn from a variety of frameworks, ranging from minority stress theory to positive youth development, to devise interventions that target isolation and connectedness in schools, community-based organisations, and in online environments. Finally, we discuss the importance of addressing social, cultural, and structural dimensions of social isolation in order to foster enabling environments that allow LGBTQ youth to thrive. This conceptual review suggests that individual and social transformations are the result of young people's meaningful participation in shaping their environment, which is made possible when their capabilities are fostered through social well-being. Our findings suggest the need for measures of social isolation among youth in databanks produced by global institutions, such as the World Health Organization.

Prevalence of HIV, STIs, and risk behaviors in a cross-sectional community- and clinic-based sample of men who have sex with men (MSM) in Lima, Peru

Background

Further research is necessary to understand the factors contributing to the high prevalence of HIV/STIs among men who have sex with men (MSM) in Peru. We compared HIV/STI prevalence and risk factors between two non-probability samples of MSM, one passively enrolled from an STI clinic and the other actively enrolled from community venues surrounding the clinic in Lima, Peru.

Methods

A total of 560 self-identified MSM were enrolled between May-December, 2007. 438 subjects enrolled from a municipal STI clinic and 122 subjects enrolled during community outreach visits. All participants underwent screening for HIV, syphilis, HSV-2, gonorrhoea, and chlamydia and completed a survey assessing their history of HIV/STIs, prior HIV testing, and sexual behavior.

Results

HIV prevalence was significantly higher among MSM enrolled from the clinic, with previously undiagnosed HIV identified in 9.1% compared with 2.6% of community participants. 15.4 % of all MSM screened were infected with ≥1 curable STI, 7.4% with early syphilis (RPR≥1∶16) and 5.5% with urethral gonorrhoea and/or chlamydia. No significant differences between populations were reported in prevalence of STIs, number of male sex partners, history of unprotected anal intercourse, or alcohol and/or drug use prior to sex. Exchange of sex for money or goods was reported by 33.5% of MSM enrolled from the clinic and 21.2% of MSM from the community (p = 0.01).

Conclusions

Our data demonstrate that the prevalence of HIV and STIs, including syphilis, gonorrhoea, and chlamydia are extremely high among MSM enrolled from both clinic and community venues in urban Peru. New strategies are needed to address differences in HIV/STI epidemiology between clinic- and community-enrolled samples of MSM.

Risk factors for the spread of HIV and other sexually transmitted infections among men who have sex with men infected with HIV in Lima, Peru

OBJECTIVES

To assess the prevalence of sexually transmitted infections (STIs), the frequency of sexual risk behaviours, and the relation between knowledge of HIV infection status and sexual risk behaviour among men who have sex with men (MSM) infected with HIV attending an STI clinic in Peru.

METHODS

We recruited a convenience sample of 559 MSM from a municipal STI clinic in Lima, Peru. Participants completed a survey and provided blood for HIV, syphilis and HSV-2 antibody testing, and urine for gonorrhoea and chlamydia nucleic acid testing.

RESULTS

Among 124 MSM with HIV, 72.6% were aware that they were infected with HIV. Active syphilis (RPR> or =1:8) was diagnosed in 21.0% of men infected with HIV, HSV-2 in 79.8%, urethral gonorrhoea in 1.6% and chlamydia in 1.6%. Among 41 participants reporting insertive anal intercourse with their last sex partner, 34.2% did not use a condom. Of the 86 participants reporting receptive anal intercourse, 25.6% did not use a condom. At least one episode of insertive unprotected anal intercourse (UAI) with a partner uninfected with HIV during the past 6 months was reported by 33.6% (35/104) of participants, and receptive UAI with a partner uninfected by HIV was reported by 44.6% (45/101). There was no difference in frequency of UAI with partners infected or uninfected with HIV observed between men who knew their serostatus compared with those who were previously undiagnosed (all p values >0.05).

CONCLUSIONS

MSM with HIV in Peru engaged in high-risk behaviours for spreading HIV and STIs. Knowledge of whether someone was infected with HIV was not associated with a decreased frequency of UAI. Additional efforts to reduce risk behaviour after the diagnosis of HIV infection are necessary.

Partner notification for sexually transmitted diseases in Peru: knowledge, attitudes, and practices in a high-risk community

OBJECTIVES

Notification and treatment of sex partners after diagnosis of a sexually transmitted disease (STD) is essential to reduce reinfection and further transmission.

GOAL

The goal of this study was to determine the prevalence of partner notification and subsequent health-seeking behavior in a high-risk population in Lima, Peru.

STUDY DESIGN

STD-infected participants of an HIV/STD prevention trial completed a questionnaire concerning partner notification.

RESULTS

Of the 502 STD-positive subjects, 287 completed the survey. Among survey participants, 65% informed their primary partner and 10.5% informed casual or anonymous partners. Reasons for failure to notify varied by partner type and included not understanding the importance of partner notification, embarrassment, fear of rejection, and inability to locate the partner. When notified, approximately one third of all partners sought medical attention.

CONCLUSIONS

Partner notification in Peru is limited by relationship dynamics, social stigma, and limited contact information. Interventions could emphasize the importance of notification, improvement of communication skills, and introduce contact tracing programs (including Internet-based systems) and expedited partner therapy.

Serologic evidence of subclinical pertussis in immunized children

Incidental to a vaccine study involving 783 immunized children conducted at two study sites, inner city children had significantly higher geometric mean pertussis agglutinin titers compared with suburban children just before the fourth dose of diphtheria-tetanus-whole cell pertussis vaccine (47 vs. 25; P less than 0.001). Higher titers in the inner city were correlated with residence in census tracts where cases of pertussis were reported. Three hundred thirty-two children in a placebo arm of the study who were clinically observed and had paired serum samples taken during a 2- to 4-month period were analyzed for evidence of natural Bordetella infection. Twelve (11%) inner city children and three (1.3%) suburban children had spontaneous 4-fold or greater rises in at least two different pertussis antibodies measured (agglutinin, antitoxin or enzyme-linked immunosorbent assay for IgG to pertussis toxin, IgG and IgA to filamentous hemagglutinin). Eighty percent of these children had IgA to filamentous hemagglutinin. Nine of 12 inner city children with serologic evidence of pertussis lived within 6 blocks of a case of pertussis reported within 1 month of the observed antibody rise in study subjects; none had a household member with pertussis and none had symptomatic disease.

Bringing testing to the people - benefits of mobile unit HIV/syphilis testing in Lima, Peru, 2007-2009

Mobile unit (MU) HIV testing is an alternative method of providing healthcare access. We compared demographic and behavioural characteristics, HIV testing history and HIV prevalence between participants seeking testing at a MU vs. fixed clinic (FC) in Lima, Peru. Our analysis included men and transgender women (TW) in Lima aged ≥ 18 years old seeking HIV testing at their first visit to a community-based MU or FC from October 2007 to November 2009. HIV testing history, HIV serostatus and behavioural characteristics were analysed. A large percentage of MU attendees self-identified as transgender (13%) or heterosexual (41%). MU attendees were more likely to engage in transactional sex (24% MU vs. 10% FC, p < 0.001), use alcohol/drugs during their last sexual encounter (24% MU vs. 20% FC, p < 0.01) and/or be a first-time HIV tester (48% MU vs. 41% FC, p < 0.001). MU HIV prevalence was 9% overall and 5% among first-time testers (49% in TW and 11% in men who have sex with men [MSM] first-time testers). MU testing reached large numbers of at-risk (MSM/TW) populations engaged in unsafe sexual behaviours, making MU outreach a worthy complement to FC testing. Investigation into whether MU attendees would otherwise access HIV testing is warranted to determine the impact of MU testing.

Pyridoxal 5'-phosphate and the regulation of ornithine decarboxylase activity and stability

There are two forms of ornithine decarboxylase with respect to pyridoxal 5'-phosphate (pyridoxal-P) affinity in exponentially-growing Swiss 3T3 mouse fibroblasts: form I (Km approximately 10 muM) accounts for 30% of the total activity, and form II (Km approximately 0.4 muM) the remainder. Each form of the enzyme is in rapid equilibrium with ornithine and pyridoxal-P; neither form recognizes the Schiff base between ornithine and pyridoxal-P as a substrate. Total pyridoxal-P concentrations indicate that both forms may normally be at least partially active in vivo. Upon stimulation of 3T3 cells by pituitary growth factors, form I becomes undetectable within 4 h. As total activity increases over 10-fold during this time and continues to increase thereafter, a possible conversion of form I to form II could account for this increase only if the Km change reflects other changes in preexisting enzyme. The rates of cofactor dissociation are apparently the same for each form and neither rate changes with the growth state. Since rapid equilibrium kinetics apply, the forms apparently differ in their rate of cofactor association. The half-lives of the two forms in vivo are the same in unstimulated cells when measured concurrently. Also, the half-life of total activity decreases markedly upon stimulation as form II becomes dominant. These and other observations are not consistent with pyridoxal-P serving a major protective function for the enzyme in vivo.