SARS-CoV-2 RNA positive pediatric organ donors: A case report

BACKGROUND

Preliminary evidence suggests that non-lung organ donation from resolved, asymptomatic or mildly symptomatic SARS-CoV-2 infected adults may be safe. However, several biological aspects of SARS-CoV-2 infection differ in children and the risk for transmission and outcomes of recipients from pediatric donors with SARS-CoV-2 infection are not well described.

METHODS

We report two unvaccinated asymptomatic pediatric non-lung organ deceased donors who tested positive for SARS-CoV-2 RNA by RT-PCR. Donor One unexpectedly had SARS-CoV-2 RNA detected in nasopharyngeal swab and plasma specimens at autopsy despite several negative tests (upper and lower respiratory tract) in the days prior to organ recovery. Donor Two had SARS-CoV- 2 RNA detected in multiple nasopharyngeal swabs but not lower respiratory tract specimens (endotracheal aspirate and bronchoalveolar lavage) during routine surveillance prior to organ recovery and was managed with remdesivir and monoclonal antibodies prior to organ recovery.

RESULTS

Two hearts, two livers and four kidneys were successfully transplanted into seven recipients. No donor to recipient transmission of SARS-CoV-2 was observed and graft function of all organs has remained excellent for up to 7 months of followup.

CONCLUSIONS

Due to the persistent gap between organ availability and the number of children waiting for transplants, deceased pediatric patients with non-disseminated SARS-CoV-2 infection, isolated to upper and/or lower respiratory tract, should be considered as potential non-lung organ donors.

CNS Persistence of HIV-1 in Children: the Untapped Reservoir

PURPOSE OF REVIEW

The central nervous system (CNS) represents a potential HIV-1 reservoir that may need to be specifically targeted by remission strategies. Perinatally HIV-1-infected children and youth are exposed to HIV-1 at a critical period of brain development. This review summarizes the current literature regarding HIV-1 and the CNS in perinatal infection.

RECENT FINDINGS

HIV-1-associated encephalopathy is prevalent with perinatal infection and neurocognitive impairment persists even following antiretroviral treatment (ART)-mediated suppression of viremia. Compartmentalization of HIV-1 between plasma and CSF of ART-naïve, perinatally infected children suggests the presence of a CNS reservoir; however, similar studies have not yet been conducted with ART suppression. CSF viral escape where CSF and plasma virus concentrations are discordant has been reported in this population, but larger studies with well-defined virologic and immunologic parameters are needed. A better understanding of HIV-1 persistence in the CNS with perinatal infection is essential for improving long-term neurocognitive outcomes and for designing strategies to induce HIV-1 remission in this population.

Quarter Century of Anti-HIV CAR T Cells

PURPOSE OF REVIEW

A therapy that might cure HIV is a very important goal for the 30-40 million people living with HIV. Chimeric antigen receptor T cells have recently had remarkable success against certain leukemias, and there are reasons to believe they could be successful for HIV. This manuscript summarizes the published research on HIV CAR T cells and reviews the current anti-HIV chimeric antigen receptor strategies.

RECENT FINDINGS

Research on anti-HIV chimeric antigen receptor T cells has been going on for at least the last 25 years. First- and second-generation anti-HIV chimeric antigen receptors have been developed. First-generation anti-HIV chimeric antigen receptors were studied in clinical trials more than 15 years ago, but did not have meaningful clinical efficacy. There are some reasons to be optimistic about second-generation anti-HIV chimeric antigen receptor T cells, but they have not yet been tested in vivo.

H1N1 influenza vaccination in HIV-infected women on effective antiretroviral treatment did not induce measurable antigen-driven proliferation of the HIV-1 proviral reservoir

Objectives

Antigen-induced activation and proliferation of HIV-1-infected cells is hypothesized to be a mechanism of HIV persistence during antiretroviral therapy. The objective of this study was to determine if proliferation of H1N1-specific HIV-infected cells could be detected following H1N1 vaccination.

Methods

This study utilized cryopreserved PBMC from a previously conducted trial of H1N1 vaccination in HIV-infected pregnant women. HIV-1 DNA concentrations and 437 HIV-1 C2V5 env DNA sequences were analyzed from ten pregnant women on effective antiretroviral therapy, before and 21 days after H1N1 influenza vaccination.

Results

HIV-1 DNA concentration did not change after vaccination (median pre- vs. post-vaccination: 95.77 vs. 41.28 copies/million PBMC, p = .37). Analyses of sequences did not detect evidence of HIV replication or proliferation of infected cells.

Conclusions

Antigenic stimulation during effective ART did not have a detectable effect on the genetic makeup of the HIV-1 DNA reservoir. Longitudinal comparison of the amount and integration sites of HIV-1 in antigen-specific cells to chronic infections (such as herpesviruses) may be needed to definitively evaluate whether antigenic stimulation induces proliferation of HIV-1 infected cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12981-017-0135-1) contains supplementary material, which is available to authorized users.

Engineering HIV-Resistant, Anti-HIV Chimeric Antigen Receptor T Cells

The treatment or cure of HIV infection by cell and gene therapy has been a goal for decades. Recent advances in both gene editing and chimeric antigen receptor (CAR) technology have created new therapeutic possibilities for a variety of diseases. Broadly neutralizing monoclonal antibodies (bNAbs) with specificity for the HIV envelope glycoprotein provide a promising means of targeting HIV-infected cells. Here we show that primary human T cells engineered to express anti-HIV CARs based on bNAbs (HIVCAR) show specific activation and killing of HIV-infected versus uninfected cells in the absence of HIV replication. We also show that homology-directed recombination of the HIVCAR gene expression cassette into the CCR5 locus enhances suppression of replicating virus compared with HIVCAR expression alone. This work demonstrates that HIV immunotherapy utilizing potent bNAb-based single-chain variable fragments fused to second-generation CAR signaling domains, delivered directly into the CCR5 locus of T cells by homology-directed gene editing, is feasible and effective. This strategy has the potential to target HIV-infected cells in HIV-infected individuals, which might help in the effort to cure HIV.

Combining Cell and Gene Therapy in an Effort to Eradicate HIV

More than 30 million people are infected with HIV, and HIV remains the fifth leading cause of disability-adjusted life years worldwide. Antiretroviral therapy (ART) dramatically decreases mortality rate, but there are side effects, long-term toxicities, expenses, stigmas, and inconveniences associated with chronic treatment, and HIV-infected individuals on ART have an increased risk of malignancies, cardiovascular disease, neurologic disease, and shortened life expectancy. Therefore, a cure for HIV remains an important goal. Combining new cell and gene therapy technology is an exciting approach that appears promising in vitro. Animal testing and careful clinical trials will be needed to determine if these strategies are clinically useful.

Efficient modification of CCR5 in primary human hematopoietic cells using a megaTAL nuclease and AAV donor template

Genetic mutations or engineered nucleases that disrupt the HIV co-receptor CCR5 block HIV infection of CD4(+) T cells. These findings have motivated the engineering of CCR5-specific nucleases for application as HIV therapies. The efficacy of this approach relies on efficient biallelic disruption of CCR5, and the ability to efficiently target sequences that confer HIV resistance to the CCR5 locus has the potential to further improve clinical outcomes. We used RNA-based nuclease expression paired with adeno-associated virus (AAV)-mediated delivery of a CCR5-targeting donor template to achieve highly efficient targeted recombination in primary human T cells. This method consistently achieved 8 to 60% rates of homology-directed recombination into the CCR5 locus in T cells, with over 80% of cells modified with an MND-GFP expression cassette exhibiting biallelic modification. MND-GFP-modified T cells maintained a diverse repertoire and engrafted in immune-deficient mice as efficiently as unmodified cells. Using this method, we integrated sequences coding chimeric antigen receptors (CARs) into the CCR5 locus, and the resulting targeted CAR T cells exhibited antitumor or anti-HIV activity. Alternatively, we introduced the C46 HIV fusion inhibitor, generating T cell populations with high rates of biallelic CCR5 disruption paired with potential protection from HIV with CXCR4 co-receptor tropism. Finally, this protocol was applied to adult human mobilized CD34(+) cells, resulting in 15 to 20% homologous gene targeting. Our results demonstrate that high-efficiency targeted integration is feasible in primary human hematopoietic cells and highlight the potential of gene editing to engineer T cell products with myriad functional properties.

HIV latency. Proliferation of cells with HIV integrated into cancer genes contributes to persistent infection

Antiretroviral treatment (ART) of HIV infection suppresses viral replication. Yet if ART is stopped, virus reemerges because of the persistence of infected cells. We evaluated the contribution of infected-cell proliferation and sites of proviral integration to HIV persistence. A total of 534 HIV integration sites (IS) and 63 adjacent HIV env sequences were derived from three study participants over 11.3 to 12.7 years of ART. Each participant had identical viral sequences integrated at the same position in multiple cells, demonstrating infected-cell proliferation. Integrations were overrepresented in genes associated with cancer and favored in 12 genes across multiple participants. Over time on ART, a greater proportion of persisting proviruses were in proliferating cells. HIV integration into specific genes may promote proliferation of HIV-infected cells, slowing viral decay during ART.

Quantification of mitochondrial toxicity in HIV-infected individuals by quantitative PCR compared to flow cytometry

BACKGROUND

Non-invasive diagnostic assays to evaluate mitochondrial toxicity could have significant clinical utility for HIV-infected individuals on antiretroviral therapy (ART).

METHODS

This study compared the ratio of mitochondrial to nuclear DNA determined by quantitative polymerase chain reaction (qPCR) to the ratio of mitochondrial to nuclear-encoded proteins by flow cytometry, in peripheral blood mononuclear cells from 73 HIV-infected individuals with and without risk factors for mitochondrial toxicity.

RESULTS

PCR detected similar mitochondrial/nuclear DNA in HIV-infected individuals without a history of ART, and those receiving ART with lipodystrophy, lipoatrophy, or a history of suspected lactic acidosis. However, the ratio was significantly greater in ART-untreated compared to those receiving either stavudine or didanosine. In contrast, flow cytometry did not detect any differences in mitochondrial/nuclear protein (Lin et al., Cytometry B 2009;76B:181-190). There was no correlation between the assays (rho = -0.05, P = 0.65).

CONCLUSIONS

Assessment of the mitochondrial/nuclear DNA ratio by qPCR performed better than the mitochondrial/nuclear-encoded protein ratio by flow cytometry to detect adverse effects of nucleoside analogs on mitochondria.

Epidemiology and aetiology of maternal parasitic infections in low- and middle-income countries

BACKGROUND

There have been very few systematic reviews looking at maternal infections in the developing world, even though cutting maternal mortality by three quarters is United Nation's Millennium Development Goal number five. This systematic review has two aims. The first is to present the prevalence of parasitic infections in the developing world over the last 30 years and the second is to evaluate the quality and distribution of research in this field.

METHODS

A systematic review of Medline, EMBASE and Global Health databases was undertaken using pre-determined search criteria. Three levels of quality criteria for exclusion of inadequate studies identified 115 out of initial 8580 titles. The data were extracted for 5 domains: worldwide pathogen prevalence, year of study, study setting, sample size and diagnostic test for each pathogen.

RESULTS

The initial search retrieved 8580 results. From these titles, 43 studies on malaria, 12 studies on helminths, 49 studies on Toxoplasma gondii, 7 studies on Chagas disease, 5 studies on Trichomonas, 1 leishmaniasis study and 1 study on trichinellosis were extracted for analysis. High prevalence of malaria was found in Gabon (up to 57%) India (55%), Cameroon (50%), Yemen (55%), Nigeria (up to 64%) and Ghana (54%). High prevalence of hookworm infections was found in Nepal at 78.8% and high values of Ascaris lumbricoides were found in Nepal, (56.2%), Kenya (52.3%) and Gabon (45.5%). High levels of Schistosoma mansoni were found in Zimbabwe (50%) and Tanzania (63.5%). The prevalence of active Toxoplasma gondii infection was found to be highest in India (27.7%).

CONCLUSION

This study highlights the large burden of maternal parasitic infections globally. It may serve as a useful starting point for health policy development and research prioritization in this area.

Epidemiology and aetiology of maternal bacterial and viral infections in low- and middle-income countries

BACKGROUND

Maternal morbidity and mortality in low- and middle-income countries has remained exceedingly high. However, information on bacterial and viral maternal infections, which are important contributors to poor pregnancy outcomes, is sparse and poorly characterised. This review aims to describe the epidemiology and aetiology of bacterial and viral maternal infections in low- and middle-income countries.

METHODS

A systematic search of published literature was conducted and data on aetiology and epidemiology of maternal infections was extracted from relevant studies for analysis. Searches were conducted in parallel by two reviewers (using OVID) in the following databases: Medline (1950 to 2010), EMBASE (1980 to 2010) and Global Health (1973 to 2010).

RESULTS

Data from 158 relevant studies was used to characterise the epidemiology of the 10 most extensively reported maternal infections with the following median prevalence rates: Treponema pallidum (2.6%), Neisseria gonorrhoeae (1.5%), Chlamydia trachomatis (5.8%), Group B Streptococcus (8.6%), bacterial vaginosis (20.9%), hepatitis B virus (4.3%), hepatitis C virus (1.4%), Cytomegalovirus (95.7% past infection), Rubella (8.9% susceptible) and Herpes simplex (20.7%). Large variations in the prevalence of these infections between countries and regions were noted.

CONCLUSION

This review confirms the suspected high prevalence of maternal bacterial and viral infections and identifies particular diseases and regions requiring urgent attention in public health policy planning, setting research priorities and donor funding towards reducing maternal morbidity and mortality in low- and middle-income countries.

Emerging biomarkers for the diagnosis of severe neonatal infections applicable to low resource settings

More than 500 000 children die each year in low resource settings due to serious neonatal infections. Better diagnostics that can be utilized in these settings to identify infected infants have the potential to significantly reduce neonatal deaths and the associated morbidity. A systematic review was performed and identified more than 250 potential new biomarkers for the diagnosis of serious neonatal infections. Eight of these biomarkers were both high-performance and high-abundance (antithrombin, inter-α inhibitor proteins, interferon-γ inducible protein-10, interleukin-1 receptor antagonist, LPS binding protein, mannose binding lectin, serum amyloid A, resistin, visfatin), and are promising for the diagnosis of serious neonatal infections in low resource settings. Future clinical trials comparing these biomarkers with more traditional biomarkers seem warranted.

Astrovirus encephalitis in boy with X-linked agammaglobulinemia

Encephalitis is a major cause of death worldwide. Although >100 pathogens have been identified as causative agents, the pathogen is not determined for up to 75% of cases. This diagnostic failure impedes effective treatment and underscores the need for better tools and new approaches for detecting novel pathogens or determining new manifestations of known pathogens. Although astroviruses are commonly associated with gastroenteritis, they have not been associated with central nervous system disease. Using unbiased pyrosequencing, we detected an astrovirus as the causative agent for encephalitis in a 15-year-old boy with agammaglobulinemia; several laboratories had failed to identify the agent. Our findings expand the spectrum of causative agents associated with encephalitis and highlight unbiased molecular technology as a valuable tool for differential diagnosis of unexplained disease.

Test of the equivalence principle using a rotating torsion balance

We used a continuously rotating torsion balance instrument to measure the acceleration difference of beryllium and titanium test bodies towards sources at a variety of distances. Our result Deltaa(N),(Be-Ti)=(0.6+/-3.1)x10(-15) m/s2 improves limits on equivalence-principle violations with ranges from 1 m to infinity by an order of magnitude. The Eötvös parameter is eta(Earth,Be-Ti)=(0.3+/-1.8)x10(-13). By analyzing our data for accelerations towards the center of the Milky Way we find equal attractions of Be and Ti towards galactic dark matter, yielding eta(DM,Be-Ti)=(-4+/-7)x10(-5). Space-fixed differential accelerations in any direction are limited to less than 8.8x10(-15) m/s2 with 95% confidence.

Characterization of a family of Arabidopsis genes related to xyloglucan fucosyltransferase1

To understand primary cell wall assembly in Arabidopsis, we have focused on identifying and characterizing enzymes involved in xyloglucan biosynthesis. Nine genes (AtFUT2-10) were identified that share between 47% and 62% amino acid similarity with the xyloglucan-specific fucosyltransferase AtFUT1. Reverse transcriptase-PCR analysis indicates that all these genes are expressed. Bioinformatic analysis predicts that these family members are fucosyltransferases, and we first hypothesized that some may also be involved in xyloglucan biosynthesis. AtFUT3, AtFUT4, and AtFUT5 were expressed in tobacco (Nicotiana tabacum L. cv BY2) suspension culture cells, and the resulting proteins did not transfer fucose (Fuc) from GDP-Fuc to tamarind xyloglucan. AtFUT3, AtFUT4, and AtFUT5 were overexpressed in Arabidopsis plants. Leaves of plants overexpressing AtFUT4 or AtFUT5 contained more Fuc than wild-type plants. Stems of plants overexpressing AtFUT4 or AtFUT5 contained more xylose, less arabinose, and less galactose than wild-type plants. We suggest that the AtFUT family is likely to include fucosyltransferases important for the synthesis of wall carbohydrates. A targeted analysis of isolated cell wall matrix components from plants altered in expression of these proteins will help determine their specificity and biological function.

Characterization of a family of Arabidopsis genes related to xyloglucan fucosyltransferase1

To understand primary cell wall assembly in Arabidopsis, we have focused on identifying and characterizing enzymes involved in xyloglucan biosynthesis. Nine genes (AtFUT2-10) were identified that share between 47% and 62% amino acid similarity with the xyloglucan-specific fucosyltransferase AtFUT1. Reverse transcriptase-PCR analysis indicates that all these genes are expressed. Bioinformatic analysis predicts that these family members are fucosyltransferases, and we first hypothesized that some may also be involved in xyloglucan biosynthesis. AtFUT3, AtFUT4, and AtFUT5 were expressed in tobacco (Nicotiana tabacum L. cv BY2) suspension culture cells, and the resulting proteins did not transfer fucose (Fuc) from GDP-Fuc to tamarind xyloglucan. AtFUT3, AtFUT4, and AtFUT5 were overexpressed in Arabidopsis plants. Leaves of plants overexpressing AtFUT4 or AtFUT5 contained more Fuc than wild-type plants. Stems of plants overexpressing AtFUT4 or AtFUT5 contained more xylose, less arabinose, and less galactose than wild-type plants. We suggest that the AtFUT family is likely to include fucosyltransferases important for the synthesis of wall carbohydrates. A targeted analysis of isolated cell wall matrix components from plants altered in expression of these proteins will help determine their specificity and biological function.

Characterization of a family of Arabidopsis genes related to xyloglucan fucosyltransferase1

To understand primary cell wall assembly in Arabidopsis, we have focused on identifying and characterizing enzymes involved in xyloglucan biosynthesis. Nine genes (AtFUT2-10) were identified that share between 47% and 62% amino acid similarity with the xyloglucan-specific fucosyltransferase AtFUT1. Reverse transcriptase-PCR analysis indicates that all these genes are expressed. Bioinformatic analysis predicts that these family members are fucosyltransferases, and we first hypothesized that some may also be involved in xyloglucan biosynthesis. AtFUT3, AtFUT4, and AtFUT5 were expressed in tobacco (Nicotiana tabacum L. cv BY2) suspension culture cells, and the resulting proteins did not transfer fucose (Fuc) from GDP-Fuc to tamarind xyloglucan. AtFUT3, AtFUT4, and AtFUT5 were overexpressed in Arabidopsis plants. Leaves of plants overexpressing AtFUT4 or AtFUT5 contained more Fuc than wild-type plants. Stems of plants overexpressing AtFUT4 or AtFUT5 contained more xylose, less arabinose, and less galactose than wild-type plants. We suggest that the AtFUT family is likely to include fucosyltransferases important for the synthesis of wall carbohydrates. A targeted analysis of isolated cell wall matrix components from plants altered in expression of these proteins will help determine their specificity and biological function.

WAKs: cell wall-associated kinases linking the cytoplasm to the extracellular matrix

There are only a few proteins identified at the cell surface that could directly regulate plant cell wall functions. The cell wall-associated kinases (WAKs) of angiosperms physically link the plasma membrane to the carbohydrate matrix and are unique in that they have the potential to directly signal cellular events through their cytoplasmic kinase domain. In Arabidopsis there are five WAKs and each has a cytoplasmic serine/threonine protein kinase domain, spans the plasma membrane, and extends a domain into the cell wall. The WAK extracellular domain is variable among the five isoforms, and collectively the family is expressed in most vegetative tissues. WAK1 and WAK2 are the most ubiquitously and abundantly expressed of the five tandemly arrayed genes, and their messages are present in vegetative meristems, junctions of organ types, and areas of cell expansion. They are also induced by pathogen infection and wounding. Recent experiments demonstrate that antisense WAK expression leads to a reduction in WAK protein levels and the loss of cell expansion. A large amount of WAK is covalently linked to pectin, and most WAK that is bound to pectin is also phosphorylated. In addition, one WAK isoform binds to a secreted glycine-rich protein (GRP). The data support a model where WAK is bound to GRP as a phosphorylated kinase, and also binds to pectin. How WAKs are involved in signaling from the pectin extracellular matrix in coordination with GRPs will be key to our understanding of the cell wall's role in cell growth.

Wall-associated kinases are expressed throughout plant development and are required for cell expansion

The mechanism by which events in the angiosperm cell wall are communicated to the cytoplasm is not well characterized. A family of five Arabidopsis wall-associated kinases (WAKs) have the potential to provide a physical and signaling continuum between the cell wall and the cytoplasm. The WAKs have an active cytoplasmic protein kinase domain, span the plasma membrane, and contain an N terminus that binds the cell wall. We show here that WAKs are expressed at organ junctions, in shoot and root apical meristems, in expanding leaves, and in response to wall disturbances. Leaves expressing an antisense WAK gene have reduced WAK protein levels and exhibit a loss of cell expansion. WAKs are covalently bound to pectin in the cell wall, providing evidence that the binding of a structural carbohydrate by a receptor-like kinase may have significance in the control of cell expansion.

Gravitropism and gravimorphism during regeneration from protoplasts of the moss Ceratodon purpureus (Hedw.) Brid

Wild-type (WT) protonemata of the moss Ceratodon purpureus grow upwards in darkness (negative gravitropism), whereas protonemata of the mutant, wrong-way response (wwr-1) grow down. Since Ceratodon protoplasts regenerate to form new protonemata, we analyzed whether the direction of filament emergence was influenced by gravity (gravimorphism) and determined the cytological events that correlated with the onset of gravitropism in WT and wwr-1 filaments formed de novo. In the WT the direction of filament emergence appeared to be gravimorphic as more than 66% of the new filaments emerged above the horizontal. In contrast, the direction of filament emergence was random in wwr-1. Tip-growing cells of both genotypes became gravitropic within a total of one to two cell divisions. Gravitropic curvature in wwr-1 was opposite in direction to that of WT, and the timing of curvature was comparable, indicating that the wwr-1 mutation acts during the onset of gravitropic competence. In time-lapse studies of both genotypes, neither a plastid-free zone nor obvious and extensive plastid sedimentation characteristic of mature dark-grown protonemata was observed in the new filaments prior to gravitropic curvature. Thus, it appears that these latter two features are not required for gravitropism in new protonemal filaments from protoplasts.

Visual loss as a complication of spine surgery. A review of 37 cases

STUDY DESIGN

Thirty-seven patients who experienced visual loss after spine surgery were identified through a survey of the members of the Scoliosis Research Society and a review of the recent literature.

OBJECTIVES

Records were reviewed in an attempt to identify preoperative and intraoperative risk factors and to assess the likelihood of recovery.

SUMMARY OF BACKGROUND DATA

Postoperative blindness after spine surgery has been documented in case reports or small series. The authors report the largest group of such cases to date and the first to allow conclusions regarding risk and prognosis.

METHODS

Letters were sent to members of the Scoliosis Research Society requesting copies of medical records concerning patients who experienced postoperative visual deficits after spine surgery. An additional 10 well-documented recent cases were identified from published reports.

RESULTS

Patients with visual loss had a mean age of 46.5 years. Surgery included instrumented posterior fusion in 92% of the cases, with an average operative time of 410 minutes and blood loss of 3500 mL. Most cases had significant intraoperative hypotension, with a mean drop in systolic blood pressure from 130 to 77 mm Hg. However, comparison with a matched group of patients with no visual symptoms showed no differences in the hematocrit or blood pressure values. Visual loss occurred because of ischemic optic neuropathy, retinal artery occlusion, or cerebral ischemia. Eleven cases were bilateral, and 15 patients had complete blindness in at least one eye. Most deficits were permanent.

CONCLUSIONS

The authors conclude that blindness after spine surgery is more common than has been recognized previously. Most cases are associated with complex instrumented fusions.

A positively gravitropic mutant mirrors the wild-type protonemal response in the moss Ceratodon purpureus

Wild-type Ceratodon purpureus (Hedw.) Brid. protonemata grow up in the dark by negative gravitropism. When upright wild-type protonemata are reoriented 90 degrees, they temporarily grow down soon after reorientation ("initial reversal") and also prior to cytokinesis ("mitotic reversal"). A positively gravitropic mutant designated wrong- way response (wwr-1) has been isolated by screening ultraviolet light-mutagenized Ceratodon protonemata. Protonemata of wwr-l reoriented from the vertical to the horizontal grow down with kinetics comparable to those of the wild-type. Protonemata of wwr-1 also show initial and mitotic reversals where they temporarily grow up. Thus, the direction of gravitropism, initial reversal, and mitotic reversal are coordinated though each are opposite in wwr-1 compared to the wild-type. Normal plastid zonation is still maintained in dark-grown wwr-1 apical cells, but the plastids are more numerous and plastid sedimentation is more pronounced. In addition, wwr-1 apical cells are wider and the tips greener than in the wild-type. These data suggest that a functional WWR gene product is not necessary for the establishment of some gravitropic polarity, for gravitropism, or for the coordination of the reversals. Thus, the WWR protein may normally transduce information about cell orientation.

Repair of a pseudarthrosis of the lumbar spine. A functional outcome study

Eighty-six patients had a total of eighty-eight primary attempts at repair of a pseudarthrosis that had developed after a localized arthrodesis in the lumbar spine. A follow-up questionnaire was sent to all patients at a mean of fifty-one months (range, twenty-five to seventy-eight months) after the operation; seventy-two patients (84 percent) completed to questionnaire. A solid fusion was ultimately achieved after the treatment of eighty-one (94 percent) of the eighty-six pseudarthroses for which radiographic data were available. With the numbers available, we could find no significant association between a solid fusion and the patient's age, gender, body-mass index, return to work, or outcome score. Despite the high rate of fusion after the index repair and subsequent procedures, only nineteen (26 percent) of the seventy-two patients who completed the questionnaire eventually had a good or excellent outcome. Seven (10 percent) had an excellent result (90 to 100 points), twelve (17 percent) had a good result (70 to 89 points), fourteen (19 percent) had a fair result (50 to 69 points), and thirty-nine (54 percent) had a poor result (less than 50 points). Nevertheless, fifty-one patients (71 percent) reported that the operation led to some improvement, and fifty-five (76 percent) said that they would have the operation again if the circumstances were similar to those before the repair of the pseudarthrosis. Thirty-four of the seventy-two patients were smokers and thirty-eight were non-smokers at the time of the operation. There was a negative linear association between the outcome scores and the number of pack-years (p = 0.02). Cessation of smoking before the operation positively affected the outcome; the patients who had stopped smoking had a mean outcome score of 65 points, compared with 45 points for those who had not stopped (p = 0.03). Patients who had stopped smoking were also more likely to return to work full time (p < 0.001). At the latest follow-up evaluation, twenty of the seventy-two patients had returned to full-time employment. Patients who had been receiving Workers' Compensation at the time of the operation generally did poorly on the outcome questionnaire, but, with the numbers available, they did not have a significantly different rate of solid fusion than patients who had not been receiving Workers' Compensation. Also, the outcome score and the rate of fusion were nor significantly affected by age or by obesity.

Spine and scalp recordings as a function of intensity. A model for changes during spinal cord monitoring

STUDY DESIGN

Spinal cord monitoring has used both spine and scalp recordings as indicators of spinal cord integrity. The relative merits of spine or scalp recordings to predict the quality of the afferent volley in the somatosensory pathway were addressed in this study by using various stimulus intensities as a way to model alterations of the size of the afferent volley.

OBJECTIVES

The results were analyzed to determine the correlation of central recordings taken at the spine or scalp with peripheral recordings.

SUMMARY OF BACKGROUND DATA

Spinal cord monitoring with somatosensory evoked potentials has been achieved with recordings of signals generated by either the spinal cord or the somatosensory cortex. Spine recordings are thought to be more stable, yet little evidence exists to document this statement.

METHODS

Seven patients were studied in the course of standard intraoperative spinal cord monitoring. Responses were recorded at the popliteal fossa, thoracic epidural, cervical spine, and scalp to tibial nerve stimulation at intensities varying from 0.5 to 2.0 times muscle twitch threshold.

RESULTS

Normalized amplitudes of the response at the popliteal fossa were used to reflect the magnitude of the afferent volley. The amplitudes of the popliteal fossa response showed a high correlation (r = 0.90) with normalized amplitudes of epidural and cervical spine responses and moderate correlation (r = 0.49) with normalized amplitudes of scalp responses. The width of the 95% confidence limits for the inverse prediction of the afferent volley from epidural and cervical responses was nearly a third narrower than that from scalp responses. At low stimulus intensities, scalp responses were consistently observed when spine responses were absent, and scalp responses had lower response thresholds than did spine responses. The latencies of the popliteal fossa responses were not well correlated with latencies of either the epidural or cervical responses.

CONCLUSIONS

These correlation and inverse prediction data suggest that the size of an afferent volley may be predicted more accurately by spine responses than by scalp responses. The presence of scalp responses at intensities too low to elicit detectable spinal-level responses suggests that scalp responses may be considered a sensitive indicator of a minimal afferent volley.

[Tolerance of preventive influenza vaccination with a subunit vaccine]

The frequency and intensity of undesirable side effects after protective vaccination against influenza with a commercially available vaccine were studied. 82 gainfully employed persons of both sexes were questioned in respect of local reactions such as weal and flare reactions, itching, sensation of heat, tenderness on pressure, and impeded movement, as well as systemic reactions e.g. elevated temperature or fever, profound sweating, headache, malaise, and insomnia. In 61 of 82 questioned persons local reactions occurred within 24 hours after vaccination, mainly weal and flare reactions and tenderness on pressure. 10 persons had systemic reactions, chiefly headache and fever, 39 of the questioned persons who reported on undesirable effects considered these impairments to be slight, whereas 28 of the group did not feel that the impairments disturbed or upset them in any way.

Azidomorphines and heterogenous opiate receptors

The N-cyclopropylmethyl derivative of azidomorphine (CAM) was found to have strong opiate agonist and antagonist activity, in various in vitro and in vivo animal tests. The derivatives of azidomorphine were not only more potent analgesics than the corresponding members of the morphine family but their lipid solubility was also markedly improved: the ratios of the median effective subcutaneous/intracerebroventricular doses are between 6.2-22.0 in the azido-group, while that of morphine is 381. The antagonist potencies of N-cyclopropyl-N-allyl azidomorphine derivatives were also quantitatively estimated in oxymorphone righting test, and were found to possess antagonists activity as potent as naloxone and more potent than other opiate antagonists (nalorphine, pentazocine Mr-1452 etc.). CAM also has been shown to produce depression of acetylcholine release from the cat lateral cerebral ventricle similarly to morphine, in a naloxone reversible manner, regardless the applied stimulus (electrical stimulation of sciatic nerve, or ouabain perfusion). CAM, similarly to bremazocine, the reported kappa opioid agonist drug, markedly increased the urinary output in normally hydrated rats. This effect was reversed by high dose of naloxone, suggesting the kappa agonist action of CAM.