A New Model of Global Reconstructive Surgery Training With Reduced Carbon Footprint of Outreach

This economic evaluation compares carbon dioxide emissions from air transportation for surgical mission trips vs team training trips.

Modeling the Lifetime Impact of Reconstructive Plastic Surgery Training: Implications for Building Capacity in Global Surgery

Background

Training local surgeons and building local surgical capacity is critical to closing the gap in unmet surgical burden in low- and middle-income country (LMIC) settings. We propose a conceptual framework to quantify the impact of a single surgeon's training across multiple generations of trainees.

Methods

A literature review was conducted to identify existing models for quantifying the impact of training. A model to estimate the attributable impact of surgical training was devised, based on a surgeon's attributable impact on a trainee and the lifetime number of cases trainees would perform. A quantitative survey was sent to high-income country and LMIC-based surgeons to determine the model's inputs across eight index procedures in reconstructive plastic surgery.

Results

We found no existing models for quantifying the multigenerational impact of training in surgery, medicine, or nonmedical fields. Twenty-eight US-based academic plastic surgeons and 19 LMIC-based surgeons representing 10 countries provided responses. The lifetime impact of multigenerational surgical training ranged from 4100 attributable cases (skin graft) to 51,900 attributable cases (cleft lip repair) in high-income countries and from 18,200 attributable cases (carpal tunnel release) to 134,300 attributable cases (cleft lip repair) in LMICs.

Conclusions

There is a sizeable impact in the first generation of training, and this impact is even greater in the second generation of training, highlighting the importance of a "multiplier effect," particularly in LMIC settings. Given the paucity of surgeons, this multiplier effect is critical in closing the surgical gap, as efforts are underway to train new cohorts of reconstructive plastic surgeons.

Patient-specific Predictors of Surgical Delay in a Large Tertiary-care Hospital Operating Room

PURPOSE

The purpose of this study was to describe patient-specific factors predictive of surgical delay in elective surgical cases.

DESIGN

Retrospective cohort study.

METHODS

Data were extracted retrospectively from the electronic health record of 32,818 patients who underwent surgery at a large academic hospital in Los Angeles between May 2012 and April 2017. Following bivariate analysis of patient-specific factors and surgical delay, statistically significant predictors were entered into a logistic regression model to determine the most significant predictors of surgical delay.

FINDINGS

Predictors of delay included having monitored anesthesia care (odds ratio [OR], 1.28; 95% confidence intervals [CI], 1.20-1.36), American Society of Anesthesiologist class 3 or above (OR, 1.21; 95% CI, 1.15-1.28), African American race (OR, 1.25; 95% CI, 1.12-1.39), renal failure (OR, 1.20; 95% CI, 1.09-1.32), steroid medication (OR, 1.13; 95% CI, 1.04-1.23) and Medicaid (OR,1.18; 95%CI, 1.09-1.30) or medicare insurance (OR, 1.14; 95% CI, 1.07-1.21). Six surgical specialties also increased the odds of delay. Obesity and cardiovascular anesthesia decreased the odds of delay.

CONCLUSIONS

Certain patient-specific factors including type of insurance, health status, and race were associated with surgical delay. Whereas monitored anesthesia care anesthesia was predictive of a delay, cardiovascular anesthesia reduced the odds of delay. Additionally, obese patients were less likely to experience a delay. While the electronic health record provided a large amount of detailed information, barriers existed to accessing meaningful data.

Economic Evaluation of a Global Reconstructive Surgery Visiting Educator Program

Objective

The objective of this study was to quantify the cost-effectiveness and economic value of a reconstructive surgery visiting educator trip program in a resource-constrained setting.

Background

Reconstructive surgical capacity remains inadequate in low- and middle-income countries, resulting in chronic disability and a significant economic toll. Education and training of the local surgical workforce to sustainably expand capacity have been increasingly encouraged, but economic analyses of these interventions are lacking.

Methods

Data were analyzed from 12 visiting educator trips and independently-performed surgical procedures at 3 Vietnamese hospitals between 2014 and 2019. A cost-effectiveness analysis was performed using standardized methodology and thresholds to determine cost-effectiveness. Sensitivity analyses were performed with disability weights, discounting, and costs from different perspectives. Economic benefit was estimated using both the human capital method and the value of a statistical life method, and a benefit-cost ratio was computed.

Results

In the base case analysis, the visiting educator program was very cost-effective at $581 per disability-adjusted life year (DALY) averted. Economic benefit was between $21·6 million and $29·3 million, corresponding to a 12- to 16-fold return on investment. Furthermore, when considering only costs to the organization, the cost decreased to $61 per DALY averted, with a 113- to 153-fold return on investment for the organization.

Conclusions

Visiting educator programs, which build local reconstructive surgical capacity in limited-resource environments, can be very cost-effective with significant economic benefit and return on investment. These findings may help guide organizations, donors, and policymakers in resource allocation in global surgery.

Fostering global data sharing: highlighting the recommendations of the Research Data Alliance COVID-19 working group

The systemic challenges of the COVID-19 pandemic require cross-disciplinary collaboration in a global and timely fashion. Such collaboration needs open research practices and the sharing of research outputs, such as data and code, thereby facilitating research and research reproducibility and timely collaboration beyond borders. The Research Data Alliance COVID-19 Working Group recently published a set of recommendations and guidelines on data sharing and related best practices for COVID-19 research. These guidelines include recommendations for clinicians, researchers, policy- and decision-makers, funders, publishers, public health experts, disaster preparedness and response experts, infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations), and other potential users. These guidelines include recommendations for researchers, policymakers, funders, publishers and infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations). Several overarching themes have emerged from this document such as the need to balance the creation of data adherent to FAIR principles (findable, accessible, interoperable and reusable), with the need for quick data release; the use of trustworthy research data repositories; the use of well-annotated data with meaningful metadata; and practices of documenting methods and software. The resulting document marks an unprecedented cross-disciplinary, cross-sectoral, and cross-jurisdictional effort authored by over 160 experts from around the globe. This letter summarises key points of the Recommendations and Guidelines, highlights the relevant findings, shines a spotlight on the process, and suggests how these developments can be leveraged by the wider scientific community.

Combining natural language processing and metabarcoding to reveal pathogen-environment associations

Cryptococcus neoformans is responsible for life-threatening infections that primarily affect immunocompromised individuals and has an estimated worldwide burden of 220,000 new cases each year—with 180,000 resulting deaths—mostly in sub-Saharan Africa. Surprisingly, little is known about the ecological niches occupied by C. neoformans in nature. To expand our understanding of the distribution and ecological associations of this pathogen we implement a Natural Language Processing approach to better describe the niche of C. neoformans. We use a Latent Dirichlet Allocation model to de novo topic model sets of metagenetic research articles written about varied subjects which either explicitly mention, inadvertently find, or fail to find C. neoformans. These articles are all linked to NCBI Sequence Read Archive datasets of 18S ribosomal RNA and/or Internal Transcribed Spacer gene-regions. The number of topics was determined based on the model coherence score, and articles were assigned to the created topics via a Machine Learning approach with a Random Forest algorithm. Our analysis provides support for a previously suggested linkage between C. neoformans and soils associated with decomposing wood. Our approach, using a search of single-locus metagenetic data, gathering papers connected to the datasets, de novo determination of topics, the number of topics, and assignment of articles to the topics, illustrates how such an analysis pipeline can harness large-scale datasets that are published/available but not necessarily fully analyzed, or whose metadata is not harmonized with other studies. Our approach can be applied to a variety of systems to assert potential evidence of environmental associations.

We expand the utility of Natural Language Processing (NLP), backtracking through metabarcodes, utilizing papers that may not mention our subject of interest, C. neoformans, in a departure from usual text analysis methods. We confirm that C. neoformans is associated with decomposing wood which is reinforced by the inferred literature studied here on C. neoformans and its close congeneric relatives. This work demonstrates the potential utility of pairing NLP with single-locus metagenetic data for the study of Neglected Tropical Diseases. While the results of this article are largely confirmatory, we present a novel method to study the ecological niches of rare pathogens that leverages the immense amount of data available to researchers in the NCBI Sequence Read Archive (SRA) combined with a text-mining analysis based on Natural Language Processing. We demonstrate that text processing, noun identification, and verb identification can play an important role in analyzing a large corpus of documents together with metagenetic data. Forging this connection requires access to all of the available ecological 18S ribosomal RNA and Internal Transcribed Spacer NCBI SRA datasets. These datasets use metabarcoding to query taxonomic diversity in eukaryotic organisms, and in the case of the Internal Transcribed Spacer, they specifically target Fungi. The presence of specific species is inferred when diagnostic 18S or ITS gene region sequences are found in the SRA data. We searched for C. neoformans in all 18S and ITS datasets available and gathered all associated journal articles that either cite the SRA data accessions or are cited in the SRA data accessions. Published metagenetic data often have associated metadata including: latitude and longitude, temperature, and other physical characteristics describing the conditions in which the metagenetic sample was collected. These metadata are not always presented in consistent formats, so harmonizing study methods may be needed to appropriately compare metagenetic data as commonly required in metanalysis studies. We present an analysis which takes as input articles associated with SRA datasets that were found to contain evidence of C. neoformans. We apply NLP methods to this corpus of articles to describe the niche of C. neoformans. Our results reinforce the current understanding of C. neoformans’s niche, indicating the pertinence of employing an NLP analysis to identify the niche of an organism. This approach could further the description of virtually any other organism that routinely appears in metagenetic surveys, especially pathogens, whose ecological niches are unknown or poorly understood.

Are we curing by cutting? A call for long-term follow up and outcomes research in global surgery interventions - perspective

Success in global surgery interventions cannot be claimed until consistent long-term follow up is achieved and corresponding outcomes are studied. However, post-operative outcomes remain inconsistently collected and analyzed in the setting of global surgery, with current efforts largely focused on the delivery of surgical care. Barriers in low- and middle-income countries include patient cost and distance, low surgical workforce capacity, poor patient health literacy, lack of affordable technology availability, inconsistent documentation, and structural deficiencies. Here, we suggest that future work can be focused on (1) enhancing systems to facilitate long-term follow up and care, (2) expanding availability and adoption of electronic medical record systems, and (3) collaboration with local surgeons in the development of international cross-organizational registries and standardized quality measures. Long-term collaborations between local healthcare administrators and providers, policymakers, international bodies, nonprofit organizations, patients, and the private sector are necessary to build and sustain processes to achieve reliable long-term follow up and rigorous data collection, with the goal of ultimately ensuring better patient outcomes.

Fostering global data sharing: highlighting the recommendations of the Research Data Alliance COVID-19 working group

The systemic challenges of the COVID-19 pandemic require cross-disciplinary collaboration in a global and timely fashion. Such collaboration needs open research practices and the sharing of research outputs, such as data and code, thereby facilitating research and research reproducibility and timely collaboration beyond borders. The Research Data Alliance COVID-19 Working Group recently published a set of recommendations and guidelines on data sharing and related best practices for COVID-19 research. These guidelines include recommendations for researchers, policymakers, funders, publishers and infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations). Several overarching themes have emerged from this document such as the need to balance the creation of data adherent to FAIR principles (findable, accessible, interoperable and reusable), with the need for quick data release; the use of trustworthy research data repositories; the use of well-annotated data with meaningful metadata; and practices of documenting methods and software. The resulting document marks an unprecedented cross-disciplinary, cross-sectoral, and cross-jurisdictional effort authored by over 160 experts from around the globe. This letter summarises key points of the Recommendations and Guidelines, highlights the relevant findings, shines a spotlight on the process, and suggests how these developments can be leveraged by the wider scientific community.

FAIR Principles: Interpretations and Implementation Considerations

The FAIR principles have been widely cited, endorsed and adopted by a broad range of stakeholders since their publication in 2016. By intention, the 15 FAIR guiding principles do not dictate specific technological implementations, but provide guidance for improving Findability, Accessibility, Interoperability and Reusability of digital resources. This has likely contributed to the broad adoption of the FAIR principles, because individual stakeholder communities can implement their own FAIR solutions. However, it has also resulted in inconsistent interpretations that carry the risk of leading to incompatible implementations. Thus, while the FAIR principles are formulated on a high level and may be interpreted and implemented in different ways, for true interoperability we need to support convergence in implementation choices that are widely accessible and (re)-usable. We introduce the concept of FAIR implementation considerations to assist accelerated global participation and convergence towards accessible, robust, widespread and consistent FAIR implementations. Any self-identified stakeholder community may either choose to reuse solutions from existing implementations, or when they spot a gap, accept the challenge to create the needed solution, which, ideally, can be used again by other communities in the future. Here, we provide interpretations and implementation considerations (choices and challenges) for each FAIR principle.

Clinical trial: renzapride treatment of women with irritable bowel syndrome and constipation - a double-blind, randomized, placebo-controlled, study

BACKGROUND

Renzapride, a 5-hydroxytryptamine type-4 (5-HT(4)) receptor agonist and 5-HT(3) receptor antagonist, has been proposed as a new treatment of irritable bowel syndrome with constipation (IBS-C).

AIM

To assess the efficacy and safety of renzapride in women with IBS-C.

METHODS

Women with IBS-C were randomized to renzapride 4 mg daily, 2 mg b.d. or placebo for 12 weeks. The primary outcome measure was global relief of IBS symptoms. A subset of patients were enrolled in a 12-month, open-label study of renzapride 4 mg daily.

RESULTS

A total of 1798 patients were included in the efficacy analysis and 971 patients entered the long-term study. The mean (S.E.M.) number of months with relief of overall IBS symptoms was 0.55 (0.04), 0.60 (0.04) and 0.44 (0.04) in the renzapride 4 mg daily, 2 mg b.d. and placebo groups (P = 0.027 and P = 0.004 respectively). Small yet statistically significant differences in favour of renzapride were observed on stool consistency and frequency, and bloating/abdominal distension scores. Renzapride was generally well tolerated; however, three episodes of ischaemic colitis were reported in the long-term study.

CONCLUSION

Given the limited increase in efficacy over placebo and the incidence of ischaemic colitis observed, our data suggest that the benefit/risk ratio of renzapride is not sufficient to warrant further study in IBS-C.

Communication, information and well-being for Australians with physical disabilities

PURPOSE

This paper is a literature review, the purpose of which was to examine the legislative framework and the Australian Government Information Policy and how this has impacted on virtual communication and the well-being of Australians with disabilities.

METHOD

This has been a systematic review of current Australian literature that considers especially how communication and information can contribute positively towards connecting people with disabilities with other people during and post-rehabilitation.

RESULTS

The results of this systematic literature review has been encouraging in that Australians with disabilities are being taken account of in the planning processes and evaluation of communications technologies.

CONCLUSION

The paper also deals with how these interactive telecommunications may play an important role by assisting persons with disabilities in dealing with the loss of a sense of control over one's destiny, which is often prevalent during the acute phase of injury in persons with disabilities.

Randomized controlled study of in-hospital exercise training programs in children with cystic fibrosis

The aim of this study was to compare aerobic and resistance training in children with cystic fibrosis (CF) admitted to hospital with an intercurrent pulmonary infection with a control group. The subjects were randomized into three groups on the first day of admission. The fat-free mass (FFM) was calculated, using the skin fold thickness from four sites (biceps, triceps, subscapular, and iliac crest). Pulmonary function tests were performed within 36 hr of admission and repeated on discharge from the hospital, and again at 1 month after discharge. All subjects performed an incremental treadmill exercise test, using a modified Bruce protocol. Lower limb strength was measured using a Cybex dynamometer. An assessment of quality of life was made using the Quality of Well Being Scale, as previously reported. Activity levels were measured using a 7-day activity diary, and subjects also wore an accelerometer on their hips. There were no significant differences between the three groups in terms of disease severity, and length of stay in hospital. Subjects in all three groups received intravenous antibiotics and nutritional supplementation as determined by the physician. Children randomized to the aerobic training group participated in aerobic activities for five sessions, each of 30-min duration, a week. The children randomized to the resistance training group exercised both upper and lower limbs against a graded resistance machine. Subjects in the control group received standard chest physiotherapy. Our study demonstrated that children who received aerobic training had significantly better peak aerobic capacity, activity levels, and quality of life than children who received the resistance training program. Children who received resistance training had better weight gain (total mass, as well as fat-free mass), lung function, and leg strength than children who received aerobic training. A combination of aerobic and resistance training may be the best training program, and future studies to assess optimal training programs for CF patients are indicated.

Leucocyte entry and endothelial E-selectin expression following intradermal Propionibacterium acnes administration

Immune responses in porcine skin to intradermal inoculation of heat-killed Propionibacterium acnes (HKPA), the major bacterial agent associated with human inflammatory acne, were studied. Pigs were chosen as experimental animals because their skin is similar in structure and composition to that of man and because the use of genetically inbred pigs enables leucocytes to be transferred between animals without eliciting rejection responses. Two pigs were sensitized intradermally with 10 mg of HKPA and were challenged 2 weeks later with doses ranging from 1-100 microg of HKPA in various intradermal sites on the ventral aspect of the abdomen. Four further pigs, previously sensitized with Bacillus Calmette-Guérin (BCG) but not HKPA, were challenged with purified protein derivative (PPD) of bovine tuberculin and HKPA. Entry of(51)Cr-labelled peripheral blood lymphocytes (PBLs) over 48 h was studied in all the challenge sites. Peak PBL entry occurred at 4 h, remaining sustained up to 24 h. There was a dose-dependent effect of HKPA on the level of PBL entry, which was antigen-specific, as few leucocytes were seen in PPD-challenge sites in HKPA-sensitized pigs or in HKPA-challenged sites in BCG-sensitized pigs. There was also a substantial influx of(111)Indium-labelled neutrophils into the lesions. Lymphocytes present were predominantly of the CD3(+)CD2(+)T-cell subset, although gammadelta TCR(+)cells were present also, particularly after 24 h. E-selectin was markedly upregulated on dermal endothelium in the P. acnes sites. The histological infiltration and kinetics were similar to those reported in human inflammatory acne.

The impact of OBRA '87 on psychiatric services in nursing homes. Joint testimony of the American Psychiatric Association and the American Association for Geriatric Psychiatry

The Institute of Medicine has formed a Committee on Improving Quality in Long-Term Care, which is examining the legislative and quality-of-care impact that the Omnibus Budget Reconciliation Act of 1987 (OBRA '87) had on long-term care. The American Psychiatric Association and the American Association for Geriatric Psychiatry were asked to provide written and oral testimony before the Committee in March 1998. The two organizations summarized the key outcomes of OBRA '87 on the psychiatric needs of individuals who receive services in long-term care settings. The written testimony also encouraged the Committee to insist that the long-term care industry develop, test, and refine psychiatric and mental health quality outcome measures for nursing facilities and other long-term care settings.

Induction of single and dual cytotoxic T-lymphocyte responses to viral proteins in mice using recombinant hybrid Ty-virus-like particles

The induction of cytotoxic T-lymphocyte (CTL) responses to viral proteins is thought to be an essential component of protective immunity against viral infections. Methods for generating such responses in a reproducible manner would be of great value in vaccine development. We demonstrate here that the recombinant antigen-presentation system based on the yeast transposon (Ty) particle-forming p1 protein is a potent means of inducing CTL responses to a variety of viral CTL epitopes, including influenza virus nucleoprotein (two epitopes), Sendai virus and vesicular stomatitis virus nucleoproteins, and the V3 loop of human immunodeficiency virus type-1 (HIV-1) gp120. CTL were primed by hybrid Ty-virus-like particles (VLP) carrying the minimal epitope or as much as 19,000 MW of protein. Ty-VLP carrying two different epitopes (dual-epitope Ty-VLP) were capable of priming CTL responses in two different strains of mice or against two epitopes in the same individual. Furthermore, co-administration of a mixture of two different Ty-VLP carrying single epitopes could induce responses to both epitopes in the same individual. Ty-VLP appear to represent a reproducible and flexible system for inducing CTL responses in mice, and warrant further evaluation in primates.

Structural similarity between the p17 matrix protein of HIV-1 and interferon-gamma

The human immunodeficiency virus (HIV) matrix protein, p17, forms the outer shell of the core of the virus, lining the inner surface of the viral membrane. The protein has several key functions. It orchestrates viral assembly via targeting signals that direct the gag precursor polyprotein, p55, to the host cell membrane and it interacts with the transmembrane protein, gp41, to retain the env-encoded proteins in the virus. In addition, p17 contains a nuclear localization signal that directs the preintegration complex to the nucleus of infected cells. This permits the virus to infect productively non-dividing cells, a distinguishing feature of HIV and other lentiviruses. We have determined the solution structure of p17 by nuclear magnetic resonance (NMR) with a root-mean square deviation for the backbone of the well-defined regions of 0.9 A. It consists of four helices connected by short loops and an irregular, mixed beta-sheet which provides a positively charged surface for interaction with the inner layer of the membrane. The helical topology is unusual; the Brookhaven protein database contains only one similar structure, that of the immune modulator interferon-gamma.

Targeted lymph node immunization with simian immunodeficiency virus p27 antigen to elicit genital, rectal, and urinary immune responses in nonhuman primates

A s.c. route of immunization was developed in non-human primates, which targets the genitourinary-rectal associated lymphoid tissue. A vaccine consisting of rSIV gag p27, expressed as hybrid Ty virus-like particles (p27: Ty-VLP) was administered in the proximity of the internal iliac lymph nodes. Secretory IgA and IgG Abs to the p27 Ag were elicited in the vaginal, male urethral, rectal and seminal fluids, urine and serum. Two or more immunodominant B cell epitopes were identified within peptides 51-90 and 121-170 of the sequence of p27, using serum or biliary IgA and IgG Abs. CD4+ T cell proliferative responses to p27 were elicited predominantly in the targeted internal iliac, as well as the inferior mesenteric lymph nodes and the spleen, but not in the unrelated lymph nodes. These cells were then studied for helper function in p27 specific B cell Ab synthesis. Specific IgA and IgG Abs were detected in the same lymphoid tissues as those that displayed proliferative responses. However, cross-over reconstitution experiments between splenic and iliac lymph node B and CD4+ T cells suggest that the iliac B cells are essential for specific IgA Ab synthesis, whereas splenic B cells preferentially synthesize IgG Ab. The targeted lymph node (TLN) route of immunization gave comparable B cell, proliferative T cell, and Th cell responses to the vaginal, male genitourinary, and rectal mucosal routes, which were augmented by oral immunization. However, the TLN route induced urinary and seminal fluid sIgA and IgG Abs in addition to genital and rectal Abs. Generating secretory IgA and IgG Abs at the mucosal surfaces, and T and B cell immunity in the regional draining lymph nodes, spleen and circulation by TLN immunization may prevent transmission of virus through the mucosa, dissemination of the virus, and the formation of a latent reservoir of infection.

Targeted lymph node immunization with simian immunodeficiency virus p27 antigen to elicit genital, rectal, and urinary immune responses in nonhuman primates

A s.c. route of immunization was developed in non-human primates, which targets the genitourinary-rectal associated lymphoid tissue. A vaccine consisting of rSIV gag p27, expressed as hybrid Ty virus-like particles (p27: Ty-VLP) was administered in the proximity of the internal iliac lymph nodes. Secretory IgA and IgG Abs to the p27 Ag were elicited in the vaginal, male urethral, rectal and seminal fluids, urine and serum. Two or more immunodominant B cell epitopes were identified within peptides 51-90 and 121-170 of the sequence of p27, using serum or biliary IgA and IgG Abs. CD4+ T cell proliferative responses to p27 were elicited predominantly in the targeted internal iliac, as well as the inferior mesenteric lymph nodes and the spleen, but not in the unrelated lymph nodes. These cells were then studied for helper function in p27 specific B cell Ab synthesis. Specific IgA and IgG Abs were detected in the same lymphoid tissues as those that displayed proliferative responses. However, cross-over reconstitution experiments between splenic and iliac lymph node B and CD4+ T cells suggest that the iliac B cells are essential for specific IgA Ab synthesis, whereas splenic B cells preferentially synthesize IgG Ab. The targeted lymph node (TLN) route of immunization gave comparable B cell, proliferative T cell, and Th cell responses to the vaginal, male genitourinary, and rectal mucosal routes, which were augmented by oral immunization. However, the TLN route induced urinary and seminal fluid sIgA and IgG Abs in addition to genital and rectal Abs. Generating secretory IgA and IgG Abs at the mucosal surfaces, and T and B cell immunity in the regional draining lymph nodes, spleen and circulation by TLN immunization may prevent transmission of virus through the mucosa, dissemination of the virus, and the formation of a latent reservoir of infection.

Mucosal model of genital immunization in male rhesus macaques with a recombinant simian immunodeficiency virus p27 antigen

Human immunodeficiency virus (HIV) can be transmitted through infected seminal fluid or vaginal or rectal secretions during heterosexual or homosexual intercourse. To prevent mucosal transmission and spread to the regional lymph nodes, an effective vaccine may need to stimulate immune responses at the genitourinary mucosa. In this study, we have developed a mucosal model of genital immunization in male rhesus macaques, by topical urethral immunization with recombinant simian immunodeficiency virus p27gag, expressed as a hybrid Ty virus-like particle (Ty-VLP) and covalently linked to cholera toxin B subunit. This treatment was augmented by oral immunization with the same vaccine but with added killed cholera vibrios. Polymeric secretory immunoglobulin A (sIgA) and IgG antibodies to p27 were induced in urethral secretions, urine, and seminal fluid. This raises the possibility that the antibodies may function as a primary mucosal defense barrier against SIV (HIV) infection. The regional lymph nodes which constitute the genital-associated lymphoid tissue contained p27-specific CD4+ proliferative and helper T cells for antibody synthesis by B cells, which may function as a secondary immune barrier to infection. Blood and splenic lymphocytes also showed p27-sensitized CD4+ T cells and B cells in addition to serum IgG and IgA p27-specific antibodies; this constitutes a third level of immunity against dissemination of the virus. A comparison of genito-oral with recto-oral and intramuscular routes of immunization suggests that only genito-oral immunization elicits specific sIgA and IgG antibodies in the urine, urethra, and seminal fluid. Both genito-oral and recto-oral immunizations induced T-cell and B-cell immune responses in regional lymph nodes, with preferential IgA antibody synthesis. The mucosal route of immunization may prevent not only virus transmission through the genital mucosa but also dissemination and latency of the virus in the draining lymph nodes.

Penetration of host cells by Rickettsia rickettsii appears to be mediated by a phospholipase of rickettsial origin

Internalization of obligate intracellular bacteria belonging to the genus Rickettsia by eukaryotic cells requires participation of both the parasitized host and the microorganism. The term "induced phagocytosis" has been used specifically to describe the entry of Rickettsia prowazekii, although a similar mechanism is likely for R. rickettsii. A role for a phospholipase in the internalization process has been proposed for both of these organisms, with the strongest supporting evidence provided for R. prowazekii. Despite general acceptance of the notion that phospholipase activity is involved in the internalization process of these bacteria, the origin of the enzyme is not known. The results of the study presented here, which used R. rickettsii and Vero cells, suggest that a rickettsial phospholipase, rather than a host cell phospholipase, mediates internalization of the organism. This conclusion is based upon results which show that pretreatment of R. rickettsii, but not of host cells, with a specific chemical inhibitor of phospholipase, and also antiserum to this enzyme, significantly reduces uptake of the organism and its ability to cause plaque formation.

Cycloleucine uptake in the brainstem of thiamine-deficient rats

Immature female rats were subjected to acute dietary deficiency of thiamine. An autoradiographic method was used in the semi-quantitative determination of concentration of 1-aminocyclopentane-1-carboxylic acid-carboxylic-14C (cycloleucine) in brainstem regions after intravenous administration of tracer quantities. The time course of tissue concentrations was followed and compared with that of normal and isocaloric control animals. Our data indicate that thiamine deficiency of sufficient magnitude to induce brainstem lesions has an effect on the transport of cycloleucine. The initial 2 min values in the nuclear areas are appreciably reduced whereas the 6 min values are significantly elevated as compared with controls; no change was demonstrated in the white matter of the inferior cerebellar peduncle. The effect on transport appears to be more on the mechanism of efflux than of influx in terms of blood brain barrier function.

Microscope densitometer system for point measurement of autoradiograms

A photometric system for measuring optical densities generated by tissue autoradiograms has been adapted to an ordinary light microscope. The optics of the microscope are used to direct the light transmitted through the autoradiogram to ocular-mounted photoconductive cells coupled to a bridge amplifier. Readout is on a digital panel meter. The integrated area analyzed varies between 33.16 to 0.02 0.02 mm2 depending on the objective magnification. The system is linear over a range of optical densities from 0.5 to 0.05.

Glucose uptake in the brainstem of thiamine-deficient rats

Acute dietary deficiency of thiamine was produced in immature female rats. Uptake of glucose by brainstem nuclei was determined by autoradiographic examination of tissue concentrations of 14-C-3-O-methyl-d-glucose following a test dose, and compared with levels in normal and isocaloric control animals. The experiment showed that glucose uptake was depressed in the lesions of thiamine deficiency as compared with the controls, that the depression occurred with the occurrence of morphologic evidence of tissue edema, and that the depression was temporally independent of the breakdown of the blood-brain barrier to protein which is found in the late, necrotic lesions.