A meta-analysis of deep brain structural shape and asymmetry abnormalities in 2,833 individuals with schizophrenia compared with 3,929 healthy volunteers via the ENIGMA Consortium

Schizophrenia is associated with widespread alterations in subcortical brain structure. While analytic methods have enabled more detailed morphometric characterization, findings are often equivocal. In this meta-analysis, we employed the harmonized ENIGMA shape analysis protocols to collaboratively investigate subcortical brain structure shape differences between individuals with schizophrenia and healthy control participants. The study analyzed data from 2,833 individuals with schizophrenia and 3,929 healthy control participants contributed by 21 worldwide research groups participating in the ENIGMA Schizophrenia Working Group. Harmonized shape analysis protocols were applied to each site's data independently for bilateral hippocampus, amygdala, caudate, accumbens, putamen, pallidum, and thalamus obtained from T1-weighted structural MRI scans. Mass univariate meta-analyses revealed more-concave-than-convex shape differences in the hippocampus, amygdala, accumbens, and thalamus in individuals with schizophrenia compared with control participants, more-convex-than-concave shape differences in the putamen and pallidum, and both concave and convex shape differences in the caudate. Patterns of exaggerated asymmetry were observed across the hippocampus, amygdala, and thalamus in individuals with schizophrenia compared to control participants, while diminished asymmetry encompassed ventral striatum and ventral and dorsal thalamus. Our analyses also revealed that higher chlorpromazine dose equivalents and increased positive symptom levels were associated with patterns of contiguous convex shape differences across multiple subcortical structures. Findings from our shape meta-analysis suggest that common neurobiological mechanisms may contribute to gray matter reduction across multiple subcortical regions, thus enhancing our understanding of the nature of network disorganization in schizophrenia.

Brain aging in major depressive disorder: results from the ENIGMA major depressive disorder working group

Major depressive disorder (MDD) is associated with an increased risk of brain atrophy, aging-related diseases, and mortality. We examined potential advanced brain aging in adult MDD patients, and whether this process is associated with clinical characteristics in a large multicenter international dataset. We performed a mega-analysis by pooling brain measures derived from T1-weighted MRI scans from 19 samples worldwide. Healthy brain aging was estimated by predicting chronological age (18-75 years) from 7 subcortical volumes, 34 cortical thickness and 34 surface area, lateral ventricles and total intracranial volume measures separately in 952 male and 1236 female controls from the ENIGMA MDD working group. The learned model coefficients were applied to 927 male controls and 986 depressed males, and 1199 female controls and 1689 depressed females to obtain independent unbiased brain-based age predictions. The difference between predicted "brain age" and chronological age was calculated to indicate brain-predicted age difference (brain-PAD). On average, MDD patients showed a higher brain-PAD of +1.08 (SE 0.22) years (Cohen's d = 0.14, 95% CI: 0.08-0.20) compared with controls. However, this difference did not seem to be driven by specific clinical characteristics (recurrent status, remission status, antidepressant medication use, age of onset, or symptom severity). This highly powered collaborative effort showed subtle patterns of age-related structural brain abnormalities in MDD. Substantial within-group variance and overlap between groups were observed. Longitudinal studies of MDD and somatic health outcomes are needed to further assess the clinical value of these brain-PAD estimates.

Exploring the implications of the first COVID-19 lockdown on patients with melanoma: a national survey

The impact of the COVID‐19 pandemic upon care of malignant melanoma (MM) remains as yet poorly understood. We undertook a UK‐wide national survey, in conjunction with a patient support group (Melanoma UK), to explore patient perceptions of the impact of the pandemic upon treatment and outpatient care of their MM. Our findings suggest that following the onset of COVID‐19, a significant minority of treatments and appointments have been delayed, there has been a shift from face‐to‐face to virtual outpatient consultations and there may be a rise in psychological comorbidities in patients with MM. We would urge clinicians to consider mental health interventions as part of a holistic care package.

Lithium prevents grey matter atrophy in patients with bipolar disorder: an international multicenter study

BACKGROUND

Lithium (Li) is the gold standard treatment for bipolar disorder (BD). However, its mechanisms of action remain unknown but include neurotrophic effects. We here investigated the influence of Li on cortical and local grey matter (GM) volumes in a large international sample of patients with BD and healthy controls (HC).

METHODS

We analyzed high-resolution T1-weighted structural magnetic resonance imaging scans of 271 patients with BD type I (120 undergoing Li) and 316 HC. Cortical and local GM volumes were compared using voxel-wise approaches with voxel-based morphometry and SIENAX using FSL. We used multiple linear regression models to test the influence of Li on cortical and local GM volumes, taking into account potential confounding factors such as a history of alcohol misuse.

RESULTS

Patients taking Li had greater cortical GM volume than patients without. Patients undergoing Li had greater regional GM volumes in the right middle frontal gyrus, the right anterior cingulate gyrus, and the left fusiform gyrus in comparison with patients not taking Li.

CONCLUSIONS

Our results in a large multicentric sample support the hypothesis that Li could exert neurotrophic and neuroprotective effects limiting pathological GM atrophy in key brain regions associated with BD.

Neuroharmony: A new tool for harmonizing volumetric MRI data from unseen scanners

•We present Neuroharmony, a harmonization tool for images from unseen scanners. •We developed Neuroharmony using a total of 15,026 sMRI images. •The tool was able to reduce scanner-related bias from unseen scans. •Neuroharmony represents a significant step towards imaging-based clinical tools. •Neuroharmony is available at https://github.com/garciadias/Neuroharmony .

The Relationship Between White Matter Microstructure and General Cognitive Ability in Patients With Schizophrenia and Healthy Participants in the ENIGMA Consortium

OBJECTIVE

Schizophrenia has recently been associated with widespread white matter microstructural abnormalities, but the functional effects of these abnormalities remain unclear. Widespread heterogeneity of results from studies published to date preclude any definitive characterization of the relationship between white matter and cognitive performance in schizophrenia. Given the relevance of deficits in cognitive function to predicting social and functional outcomes in schizophrenia, the authors carried out a meta-analysis of available data through the ENIGMA Consortium, using a common analysis pipeline, to elucidate the relationship between white matter microstructure and a measure of general cognitive performance, IQ, in patients with schizophrenia and healthy participants.

METHODS

The meta-analysis included 760 patients with schizophrenia and 957 healthy participants from 11 participating ENIGMA Consortium sites. For each site, principal component analysis was used to calculate both a global fractional anisotropy component (gFA) and a fractional anisotropy component for six long association tracts (LA-gFA) previously associated with cognition.

RESULTS

Meta-analyses of regression results indicated that gFA accounted for a significant amount of variation in cognition in the full sample (effect size [Hedges' g]=0.27, CI=0.17-0.36), with similar effects sizes observed for both the patient (effect size=0.20, CI=0.05-0.35) and healthy participant groups (effect size=0.32, CI=0.18-0.45). Comparable patterns of association were also observed between LA-gFA and cognition for the full sample (effect size=0.28, CI=0.18-0.37), the patient group (effect size=0.23, CI=0.09-0.38), and the healthy participant group (effect size=0.31, CI=0.18-0.44).

CONCLUSIONS

This study provides robust evidence that cognitive ability is associated with global structural connectivity, with higher fractional anisotropy associated with higher IQ. This association was independent of diagnosis; while schizophrenia patients tended to have lower fractional anisotropy and lower IQ than healthy participants, the comparable size of effect in each group suggested a more general, rather than disease-specific, pattern of association.

Age-Related Changes in Topological Degradation of White Matter Networks and Gene Expression in Chronic Schizophrenia

Current hypotheses stipulate core symptoms of schizophrenia (SZ) result from the brain's incapacity to integrate neural processes. Converging diffusion magnetic resonance imaging and graph theory studies provide evidence of macrostructural alterations in SZ. However, age-related topological changes within and between white matter (WM) networks and its relationship to gene expression with disease progression remain incompletely understood. This cross-sectional study uses network modeling to investigate changes in WM network organization with disease progression in chronic SZ as well its relationship with gene expression in healthy brains. First, we replicate prior findings demonstrating altered global WM network topology in SZ. Novel results show significantly altered age-related network degradation patterns in patients compared with controls. Specifically, controls show stereotyped, linear global network decline with age. In contrast, patients show nonlinear network decline with age. Further analysis reveals lack of significant topological decline in younger adult patients, which is subsequently followed by stereotyped linear decline in older adult patients. Node-specific analyses show significant topological differences in frontal and limbic regions of younger adult patients compared with age-matched controls, which become less pronounced with age in older adult patients compared with age-matched controls. Lastly, we show several gene expression profiles, including DISC1, are associated with age-related changes in WM disconnectivity. Together, these findings provide novel WM topological and genetic evidence supporting neurodevelopmental models of SZ, suggesting that network remodeling continues throughout the third decade of life before stabilizing.

Widespread white matter microstructural differences in schizophrenia across 4322 individuals: results from the ENIGMA Schizophrenia DTI Working Group

The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.

Circulating immunoreactive substance P in man

Immunoreactive substance P (iSP) has been measured in plasma in 77 normal subjects and in 125 hospital patients. Factors affectingin-vitro degradation of iSP were studied.In vivo, iSP is degraded in the liver and its level in the circulation is independent of kidney excretory function.During insulin-induced hypoglycaemic stress and also during glucose-tolerance test, iSP in plasma decreased transiently. No circadian rhythm of iSP was observed, but in a study in sleeping volunteers episodic secretory bursts were seen, separated by one- to two-hour intervals, the first peak appearing about 90 minutes after the subjects fell asleep.In a patient with carcinoid metastases in the liver, an elevated level of iSP was found in the general circulation with a marked gradient at the hepatic venous effluent.

The miR-137 schizophrenia susceptibility variant rs1625579 does not predict variability in brain volume in a sample of schizophrenic patients and healthy individuals

The micro RNA 137 (miR-137) variant rs1625579 has been identified as a genome-wide significant risk variant for schizophrenia. miR-137 has an established role in neurodevelopment and may mediate cognitive dysfunction in schizophrenia. This role of miR-137 may be related to changes in brain morphology for risk-related genotypes; however this has not yet been delineated. Here we considered whether rs1625579 genotype was predictive of indices of brain structure in patients with schizophrenia and healthy controls. Structural magnetic resonance imaging (sMRI) data (i.e. 3T T1-TFE or 1.5T T1-MPRAGE) were acquired from 150 healthy controls and 163 schizophrenic patients. Two volumetric analyses that considered the impact of miR-137/rs1625579 genotype were carried out on sMRI data. In the first analysis, voxel based morphometry was employed to consider genotype-related variability in local grey and white matter across the entire brain volume. Our secondary analysis utilized the FIRST protocol in FSL to consider the volume of subcortical structures (i.e. bilateral accumbens, amygdala, caudate, hippocampus, pallidum, putamen and thalamus). Several brain regions in both analyses demonstrated the expected main effect of participant group (i.e. schizophrenics < controls), yet there were no regions where we observed an impact of rs1635579 genotype on brain volume. Our analyses suggest that the mechanism by which miR-137 confers risk for schizophrenia and impacts upon cognitive function may not be mediated by changes in local brain volume. However, it remains to be determined whether or not alternative measures of brain structure are related to these functions of miR-137.

White matter microstructural abnormalities in families multiply affected with bipolar I disorder: a diffusion tensor tractography study

BACKGROUND

White matter (WM) abnormalities are proposed as potential endophenotypic markers of bipolar disorder (BD). In a diffusion tensor imaging (DTI) voxel-based analysis (VBA) study of families multiply affected with BD, we previously reported that widespread abnormalities of fractional anisotropy (FA) are associated with both BD and genetic liability for illness. In the present study, we further investigated the endophenotypic potential of WM abnormalities by applying DTI tractography to specifically investigate tracts implicated in the pathophysiology of BD.

METHOD

Diffusion magnetic resonance imaging (MRI) data were acquired from 19 patients with BD type I from multiply affected families, 21 of their unaffected first-degree relatives and 18 healthy volunteers. DTI tractography was used to identify the cingulum, uncinate fasciculus (UF), arcuate portion of the superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF), corpus callosum, and the anterior limb of the internal capsule (ALIC). Regression analyses were conducted to investigate the effect of participant group and genetic liability on FA and radial diffusivity (RD) in each tract.

RESULTS

We detected a significant effect of group on both FA and RD in the cingulum, SLF, callosal splenium and ILF driven by reduced FA and increased RD in patients compared to controls and relatives. Increasing genetic liability was associated with decreased FA and increased RD in the UF, and decreased FA in the SLF, among patients.

CONCLUSIONS

WM microstructural abnormalities in limbic, temporal and callosal pathways represent microstructural abnormalities associated with BD whereas alterations in the SLF and UF may represent potential markers of endophenotypic risk.

Genomic analysis of filoviruses associated with four viral hemorrhagic fever outbreaks in Uganda and the Democratic Republic of the Congo in 2012

In 2012, an unprecedented number of four distinct, partially overlapping filovirus-associated viral hemorrhagic fever outbreaks were detected in equatorial Africa. Analysis of complete virus genome sequences confirmed the reemergence of Sudan virus and Marburg virus in Uganda, and the first emergence of Bundibugyo virus in the Democratic Republic of the Congo.

Deviated nasal septum hinders intranasal sprays: a computer simulation study

BACKGROUND

This study investigates how deviated nasal septum affects the quantity and distribution of spray particles, and examines the effects of inspiratory airflow and head position on particle transport.

METHODS

Deposition of spray particles was analysed using a three-dimensional computational fluid dynamics model created from a computed tomography scan of a human nose with leftward septal deviation and a right inferior turbinate hypertrophy. Five simulations were conducted using FluentTM software, with particle sizes ranging from 20-110 &#956;m, a spray speed of 3 m/s, plume angle of 68(deg), and with steady state inspiratory airflow either present (15.7 L/min) or absent at varying head positions.

RESULTS

With inspiratory airflow present, posterior deposition on the obstructed side was approximately four times less than the contralateral side, regardless of head position, and was statistically significant. When airflow was absent, predicted deposition beyond the nasal valve on the left and right sides were between 16% and 69% lower and positively influenced by a dependent head position.

CONCLUSION

Simulations predicted that septal deviation significantly diminished drug delivery on the obstructed side. Furthermore, increased particle penetration was associated with presence of nasal airflow. Head position is an important factor in particle deposition patterns when inspiratory airflow is absent.

Genome-wide linkage in Utah autism pedigrees

Genetic studies of autism over the past decade suggest a complex landscape of multiple genes. In the face of this heterogeneity, studies that include large extended pedigrees may offer valuable insights, as the relatively few susceptibility genes within single large families may be more easily discerned. This genome-wide screen of 70 families includes 20 large extended pedigrees of 6-9 generations, 6 moderate-sized families of 4-5 generations and 44 smaller families of 2-3 generations. The Center for Inherited Disease Research (CIDR) provided genotyping using the Illumina Linkage Panel 12, a 6K single-nucleotide polymorphism (SNP) platform. Results from 192 subjects with an autism spectrum disorder (ASD) and 461 of their relatives revealed genome-wide significance on chromosome 15q, with three possibly distinct peaks: 15q13.1-q14 (heterogeneity LOD (HLOD)=4.09 at 29 459 872 bp); 15q14-q21.1 (HLOD=3.59 at 36 837 208 bp); and 15q21.1-q22.2 (HLOD=5.31 at 55 629 733 bp). Two of these peaks replicate earlier findings. There were additional suggestive results on chromosomes 2p25.3-p24.1 (HLOD=1.87), 7q31.31-q32.3 (HLOD=1.97) and 13q12.11-q12.3 (HLOD=1.93). Affected subjects in families supporting the linkage peaks found in this study did not reveal strong evidence for distinct phenotypic subgroups.

Ethyl 6-amino-2-methoxypyridine-3-carboxylate, interplay of molecular and supramolecular structure

The title compound, C(9)H(12)N(2)O(3), crystallizes with two molecules in the asymmetric unit. There is extensive hydrogen bonding which results in the formation of a two-dimensional corrugated sheet. This supramolecular structure is determined by the formation of hydrogen-bonded chains resulting from the presence of a 6-amino group and an ethoxycarbonyl group as substituents on a pyridine ring in relative para positions which constitute a pi-electron 'push-pull' system.

Bis[N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxypyrimidin-2-yl)glycyl-glycinato]triaquacalcium: coordination polymer chains linked by hydrogen bonds

In the title compound, [Ca(C9H11N6O5)2(H2O)3], the Ca atom lies on a twofold rotation axis in C2/c and the three water molecules are all disordered, each over two sites having equal occupancy. The anion acts as a bridging ligand between pairs of Ca sites on the same twofold axis, thus forming a one-dimensional coordination polymer, with the chains lying along the twofold axes. These chains are linked by multiple O-H...O and N-H...O hydrogen bonds into a single three-dimensional framework.

Soft C—H...O hydrogen bonds in methyl 2,4-dinitrobenzenesulfenate: sheets built fromR22(10) andR66(42) rings

Molecules of the title compound, C(7)H(6)N(2)O(5)S, are linked into sheets containing R(2)(2)(10) and R(6)(6)(42) rings by C-H.O hydrogen bonds [C.O 3.405 (3) and 3.511 (2) A; C-H.O 159 and 169 degrees ], in which both acceptors are in the same nitro group. Comparisons are made with the hydrogen bonding in other nitrobenzenesulfenate esters.

N-(2-Amino-1,6-dihydro-5-nitroso-6-oxopyrimidin-4-yl)-L-isoleucine-water (4/1): interplay of molecular and supramolecular structures

In the title compound, 2C10H15N5O4-0.5H2O, there are two independent molecules of the pyrimidinylisoleucine in general positions and a water molecule lying on a twofold rotation axis. The bond lengths within the organic moieties demonstrate significant polarization of the electronic structure. Each of the organic molecules participates in 12 intermolecular hydrogen bonds, of O-H...O and N-H...O types, while the water molecule acts as a double donor and as a double acceptor of O-H...O hydrogen bonds. The organic components are linked by the hydrogen bonds into a single three-dimensional framework, reinforced by the water molecules.

Methyl 7-hydroxy-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropteridine-6-carboxylate–dimethyl sulfoxide (1/1) forms chains containing O—H...O and C—H...O hydrogen bonds and aromatic π–π-stacking interactions

In the title compound, C11H12N4O5-C2H6OS, the molecular components are linked by a short hydrogen bond with dimensions O...O 2.517 (2) A and O-H...O 168 degrees. Paired C-H...O hydrogen bonds [C...O 3.362 (2) and 3.382 (2) A; C-H...O 157 and 140 degrees] generate cyclic centrosymmetric four-component aggregates reinforced by aromatic pi-pi-stacking interactions, and further C-H...O hydrogen bonds [C.O 3.472 (3) and 3.521 (2) A; C-H...O 156 and 157 degrees] link these aggregates into chains.

Hydrogen bonding in substituted nitroanilines: isolated nets in 1,3-diamino-4-nitrobenzene and continuously interwoven nets in 3,5-dinitroaniline

Molecules of 1,3-diamino-4-nitrobenzene, C(6)H(7)N(3)O(2), are linked by N-H.O hydrogen bonds [N.O 2.964 (2) and 3.021 (2) A; N-H.O 155 and 149 degrees] into (4,4) nets. In 3,5-dinitroaniline, C(6)H(5)N(3)O(4), where Z' = 2, the molecules are linked by three N-H.O hydrogen bonds [N.O 3.344 (2)-3.433 (2) A and N-H.O 150-167 degrees] into deeply puckered nets, each of which is interwoven with its two immediate neighbours.

A cohort study of health care workers to assess nosocomial transmissibility of Nipah virus, Malaysia, 1999

During 1998-1999, an outbreak of Nipah virus encephalitis occurred in Malaysia. To assess the possibility of nosocomial transmission, 338 health care workers (HCWs) exposed and 288 HCWs unexposed to outbreak-related patients were surveyed, and their serum samples were tested for anti-Nipah virus antibody. Needlestick injuries were reported by 12 (3%) HCWs, mucosal surface exposure to body fluids by 39 (11%), and skin exposure to body fluids by 89 (25%). No encephalitis occurred in either group. Three exposed and no unexposed HCWs tested positive by EIA for IgG antibodies. It is likely that these 3 were false positives; no IgM response occurred, and the serum samples were negative for anti-Nipah virus neutralizing antibodies. The risk of nosocomial transmission of Nipah virus appears to be low; however, given the high case-fatality rate and the presence of virus in respiratory secretions and urine of some patients, standard and droplet infection-control practices should be maintained with these patients.

An instrumented glove for grasp specification in virtual-reality-based point-and-direct telerobotics

Hand posture and force, which define aspects of the way an object is grasped, are features of robotic manipulation. A means for specifying these grasping "flavors" has been developed that uses an instrumented glove equipped with joint and force sensors. The new grasp specification system will be used at the Pennsylvania State University (Penn State) in a Virtual Reality based Point-and-Direct (VR-PAD) robotics implementation. Here, an operator gives directives to a robot in the same natural way that human may direct another. Phrases such as "put that there" cause the robot to define a grasping strategy and motion strategy to complete the task on its own. In the VR-PAD concept, pointing is done using virtual tools such that an operator can appear to graphically grasp real items in live video. Rather than requiring full duplication of forces and kinesthetic movement throughout a task as is required in manual telemanipulation, hand posture and force are now specified only once. The grasp parameters then become object flavors. The robot maintains the specified force and hand posture flavors for an object throughout the task in handling the real workpiece or item of interest. In the Computer integrated Manufacturing (CIM) Laboratory at Penn State, hand posture and force data were collected for manipulating bricks and other items that require varying amounts of force at multiple pressure points. The feasibility of measuring desired grasp characteristics was demonstrated for a modified Cyberglove impregnated with Force-Sensitive Resistor (FSR) (pressure sensors in the fingertips. A joint/force model relating the parameters of finger articulation and pressure to various lifting tasks was validated for the instrumented "wired" glove. Operators using such a modified glove may ultimately be able to configure robot grasping tasks in environments involving hazardous waste remediation, flexible manufacturing, space operations and other flexible robotics applications. In each case, the VR-PAD approach will finesse the computational and delay problems of real-time multiple-degree-of-freedom force feedback telemanipulation.

Gas chromatographic determination of methamphetamine and its metabolite amphetamine in human plasma and urine following conversion to N-propyl derivatives

A gas chromatographic method for the simultaneous determination of methamphetamine and its metabolite amphetamine in human plasma and urine is described. The method utilizes reductive alkylation with propionaldehyde and sodium borohydride to produce N-propyl derivatives, which have excellent chromatographic properties. Structural analogs of the analytes, p-methylmethamphetamine and p-methylamphetamine, are used as internal standards. The method has good precision and accuracy for concentrations ranging from less than 10 ng/ml to 5000 ng/ml and has been used to measure plasma concentrations as part of a pharmacokinetic/pharmacodynamic study of methamphetamine in humans.

Selective inhibition of human immunodeficiency viruses by racemates and enantiomers of cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine

2',3'-Dideoxy-5-fluoro-3'-thiacytidine (FTC) has been shown to be a potent and selective compound against human immunodeficiency virus type 1 in acutely infected primary human lymphocytes. FTC is also active against human immunodeficiency virus type 2, simian immunodeficiency virus, and feline immunodeficiency virus in various cell culture systems, including human monocytes. The antiviral activity can be prevented by 2'-deoxycytidine, but not by other natural nucleosides, suggesting that FTC must be phosphorylated to be active and 2'-deoxycytidine kinase is responsible for the phosphorylation. By using chiral columns or enzymatic techniques, the two enantiomers of FTC were separated. The (-)-beta-enantiomer of FTC was about 20-fold more potent than the (+)-beta-enantiomer against human immunodeficiency virus type 1 in peripheral blood mononuclear cells and was also effective in thymidine kinase-deficient CEM cells. Racemic FTC and its enantiomers were nontoxic to human lymphocytes and other cell lines at concentrations of up to 100 microM. Studies with human bone marrow cells indicated that racemic FTC and its (-)-enantiomer had a median inhibitory concentration of > 30 microM. The (+)-enantiomer was significantly more toxic than the (-)-enantiomer to myeloid progenitor cells. The susceptibilities to FTC of pretherapy isolates in comparison with those of posttherapy 3'-azido-3'-deoxythymidine-resistant viruses in human lymphocytes were not substantially different. Similar results were obtained with well-defined 2',3'-dideoxyinosine- and nevirapine-resistant viruses. (-)-FTC-5'-triphosphate competitively inhibited human immunodeficiency virus type 1 reverse transcriptase, with an inhibition constant of 2.9 microM, when a poly(I)n.oligo(dC)19-24 template primer was used. These results suggest that further development of the (-)-Beta-enantiomer of FTC is warranted as an antiviral agent for infections caused by human immunodeficiency viruses.

Activities of the four optical isomers of 2',3'-dideoxy-3'-thiacytidine (BCH-189) against human immunodeficiency virus type 1 in human lymphocytes

Four different isomers of 2',3'-dideoxy-3'-thiacytidine [beta-DL-(+-)-BCH-189] were evaluated in primary human lymphocytes infected with human immunodeficiency virus type 1. The beta-L-(-) isomer was the most potent enantiomer, with a median effective concentration of 1.8 nM and no discernible cytotoxicity up to 100 microM. The relative order of potencies for the isomers was beta-L-(-) greater than beta-DL-(+-) racemic greater than beta-D-(+) greater than alpha-L-(+) greater than alpha-D-(-). The beta-L-(-) enantiomer was as potent as 3'-azido-3'-deoxythymidine.

Role of affect and personality in gastric acid secretion and serum gastrin concentration. Comparative studies in normal men and in male duodenal ulcer patients

The role of mood state (affect) and personality on basal acid secretion and basal serum gastrin concentrations were examined in seven healthy men and eight patients with duodenal ulcer. In each subject, gastric secretion and affect were assessed simultaneously on 5 separate days. None of 10 self-reported affect variables correlated with daily fluctuations in basal acid secretion in either group. Three variables (tension, conflict, and anxiety) correlated significantly with serum gastrin fluctuations in normal subjects, but these relationships were not present in patients with ulcer, who were hypergastrinemic regardless of their affective state. The degree to which serum gastrin fluctuated was unrelated to personality, as assessed by Minnesota Multiphasic Personality Inventory. On the other hand, several Minnesota Multiphasic Personality Inventory scales correlated with the degree of variability in basal acid secretion, including scales that measured impulsivity and social isolation/alienation. These studies indicate that serum gastrin concentrations are related to affective state in normal men, that this relationship is altered in men with duodenal ulcer, and that certain personality traits, such as impulsivity and social isolation, are associated with more labile basal acid secretion rates.

Comparing two sampling techniques for endocervical cell recovery on Papanicolaou smears

The importance of endocervical cells in a Pap smear is well-recognized. A Pap smear lacking endocervical cells is considered inadequate and necessitates a repeat test. Clinicians continue to search for techniques that will ensure consistently adequate samples. In this study, Pap smears were obtained for 200 subjects, alternating use of a saline-moistened cotton-tipped applicator with the Zelsmyr Cytobrush for endocervical cell collection. Endocervical cells were present in all 100 Cytobrush smears, compared with 91 of the cotton-tipped applicator smears. The difference is significant (p less than 0.005). The nine smears that lacked endocervical cells were repeated, using the Cytobrush; all nine repeat smears contained endocervical cells. Although the sample used in this study was small, results indicate that the Cytobrush is more effective in obtaining endocervical cells than the cotton-tipped applicator. Use of the Cytobrush is recommended in the interest of reducing the number of false negative reports.

Effects of increased cardiac output on pulmonary blood flow distribution during lobar ventilation hypoxia and collapse

Electromagnetic flow probes were placed around the pulmonary artery and left lower lobe artery in anaesthetized open-chest dogs in order to measure possible changes in the ratio of lobar-to-total pulmonary blood flow (Ql/Qt) in response to changes in cardiac output produced by the opening of arterio-venous fistulae or fluid loading. Ventilation of the lobe with 7% oxygen or lobar collapse reduced Ql/Qt by 35% and 42%, respectively, but there were no significant changes in Ql/Qt in response to increases in Qt of 29-133%. It is concluded that the changes in Qt, pulmonary vascular pressures and mixed venous PO2 within the range studied did not influence Ql/Qt.

Effects of altered patterns of ventilation and of increased cardiac output on blood flow to a collapsed lung in anaesthetized, closed-chest dogs

Right-to-left shunt (Qs/Qt) was measured by the SF6 and oxygen methods in 13 anaesthetized closed-chest dogs intubated with a double-lumen endobronchial tube. Collapse of the left lung increased Qs/Qt from 10% to 23%, suggesting that blood flow to the left lung had been reduced by about 60%. Increasing right lung mean airway pressure by the alteration of the inspiratory:expiratory time ratio or the application of PEEP produced a small but non-significant increase in Qs/Qt with significant increases in arterial and mixed venous carbon dioxide tensions, and arterial to right lung end-tidal carbon dioxide tension difference. Fluid loading during collapse increased cardiac output and pulmonary vascular pressures, but Qs/Qt did not differ significantly from the normovolaemic collapsed state. Increasing the right mean airway pressure in this condition had no effect on Qs/Qt or carbon dioxide tensions.

Effects of the pattern of ventilation and of an increase in cardiac output on the distribution of blood flow to a hypoxic lung lobe

Electromagnetic flow probes were used to measure the fraction of the pulmonary blood flow perfusing the left lower lobe (Ql/Qt) in 16 anaesthetized, open-chest dogs in order to study the effects of right lung airway pressure on the distribution of blood flow to a hypoxic lung lobe. Ventilation of the lobe with 7% oxygen in nitrogen resulted in a 37% reduction in Ql/Qt at the beginning and end of the main procedure, thus confirming that the hypoxic pulmonary vasoconstrictor response was unchanged throughout the study. The effects of varying mean airway pressure to the right lung by changing inspiratory:expiratory time ratio and by the addition of a positive end-expiratory pressure were studied when the left lower lobe was insufflated with oxygen or 7% oxygen in nitrogen, or was collapsed. Insufflation of the lobe with 7% oxygen in nitrogen and collapse reduced Ql/Qt by 61% and 66%, respectively. However, changing mean airway pressure in the right lung produced no significant changes in Ql/Qt in any of the different lobar conditions or when collapse was produced after fluid loading. Fluid loading during collapse increased cardiac output and pulmonary vascular pressures and increased Ql/Qt to a value which was not significantly different from lobar ventilation with 7% oxygen in nitrogen. It is concluded that moderate increases in mean airway pressure do not increase Ql/Qt when this has been reduced by exposure of the lobe to mixed venous blood-gas tensions.

Reversal of nitrous oxide-induced depression of hypoxic pulmonary vasoconstriction by lignocaine hydrochloride during collapse and ventilation hypoxia of the left lower lobe

The blood flow to the left lower lobe (QL), and total (QT) pulmonary blood flow, were measured in 10 open-chest dogs using electromagnetic flowmeters. Ventilation of the left lower lobe with 7% oxygen in nitrogen produced a greater reduction in QL/QT (41%) than lobar ventilation with 7% oxygen in nitrous oxide (33%). Lobar collapse reduced QL/QT by 65%, but there was no change in QL/QT when 50% nitrous oxide was administered to the right lung. The i.v. infusion of lignocaine hydrochloride during ventilation of the lobe with 7% oxygen in nitrogen produced no change in QL/QT. However, lignocaine infusion during lobar ventilation with 7% oxygen in nitrous oxide produced a further reduction in QL/QT to a value which was not significantly different from that observed during ventilation with 7% oxygen in nitrogen. Lignocaine had no effect on QL/QT during lobar collapse whether the right lung was ventilated with 50% oxygen in nitrogen or 50% oxygen in nitrous oxide. It is concluded that lignocaine reverses the depression of hypoxic pulmonary vasoconstriction produced by lobar ventilation with nitrous oxide.

Effect of lignocaine and nitrous oxide on hypoxic pulmonary vasoconstriction in the dog constant-flow perfused left lower lobe preparation

The effects of lignocaine hydrochloride on hypoxic pulmonary vasoconstriction in the presence and absence of nitrous oxide were examined during constant-flow perfusion of the left lower lobe. Lignocaine had no effect on lobar pulmonary vascular resistance during lobar ventilation with oxygen or 7% oxygen in nitrogen. The substitution of nitrous oxide for nitrogen diminished the hypoxic vasoconstrictor response, whilst the subsequent infusion of lignocaine during 7% oxygen in nitrous oxide increased the response to a value which was not significantly different from that produced by 7% oxygen in nitrogen alone.

Substance P in the blood plasma in hypophysial portal vessels

The aim of the present study was to check if Substance P (SP) is released from the hypothalamus into the hypophysial portal vessels and by this route exerts its direct influence on the adenohypophysis. For this purpose SP radioimmunoactivity was assayed in the blood plasma collected from hypophysial portal vessels and from the cephalic end of the external jugular vein. The SP levels in blood plasma collected from hypophysial portal vessels and from the jugular vein do not differ significantly. Neither does application of a noxious factor, such as bilateral femoral bone fracture, change significantly the SP level in the blood plasma from portal vessels and from the jugular vein. Hypoxia seems to increase the SP level in portal blood plasma and may be followed by its decrease. It is concluded that hypothalamic SP is not released into the hypophysial portal vessels under normal conditions and its direct influence on the adenohypophysis is not mediated this way.

Immunoreactive substance P and LH-RH content in median eminence and pituitary gland during proestrus, oestrus, lactation and after anterior hypothalamic deafferentation

Substance P (SP) and luteinizing hormone releasing hormone (LH-RH) content were measured by radioimmunoassay in median eminence of female rats, SP only in rats pituitary after decapitation on the day of oestrus (E), on the first and second day of dioestrus (D1 and D2), on the day of proestrus (P) and in "constant oestrus" (AD) caused by anterior hypothalamic deafferentation and in lactation (L). During four days of oestrus cycle the highest SP and LH-RH content of median eminence was found in dioestrus. Both during cyclic oestrus and "constant oestrus", SP and LH-RH were significantly lower than on the second day of dioestrus. These results may suggest the reciprocal functional relation of both hypothalamic peptides in the mechanism of the control of gonadotropin release. The highest LH-RH concentration of the median eminence was found in the animals on the 11th to 15th day of lactation, while the SP content in the median eminence of these animals is not significantly different from those of the remaining groups except the value for dioestrus (D2) rats. The SP content in pituitary of lactating rats was significantly higher than those of rats during cyclic or "constant oestrus".

Delayed reaction to the Dacron buttress used in urethropexy

Eleven patients developed a delayed reaction to the Dacron buttress used in Stamey urethropexy. The reaction was characterized by pain, dyspareunia, vaginal discharge and/or bleeding, induration of the abdominal incision, vaginal granulation tissue and draining abdominal or vaginal sinus tracts. This complication occurred in 5% of the 163 patients we treated with the Stamey procedure for stress urinary incontinence. Treatment consisted of removal of the nylon suture and Dacron buttress. None of the 11 patients developed recurrent incontinence. The subjective cure rate for stress urinary incontinence was 92% using the Stamey procedure.

Nonoperative treatment of the acute tear-drop fracture of the cervical spine

The tear-drop fracture is a severe injury to the cervical spine often associated with severe cord damage. Previous authors have reported high rates of instability after nonoperative treatment of this injury and have recommended early surgical fusion. During the period from January 1978 to December 1979, ten patients with acute tear-drop fractures were treated nonoperatively. Only one required surgical fusion because of latent instability. Contrary to previous reports, adequate stability of the cervical spine was achieved nonoperatively when the spinal canal had been adequately realigned by a closed method of treatment.

Immunoreactive substance P content in median eminence and pituitary gland during oestrus, dioestrus and after anterior hypothalamic deafferentation

The aim of the present study was to find a relation between the Substance P (SP) content in the median eminence and the pituitary gland in rats and hypothalamic regulaton of the oestrus cycle. SP content was measured by radioimmunoassay in female rat pituitary and median eminence during oestrus, dioestrus and after anterior hypothalamic deafferentation. SP content in rat's pituitary did not vary significantly among individual groups of animals. The greatest average SP content in rat's median eminence was found in dioestrus. Both during cyclic and constant oestrus resulting from anterior hypothalamic deafferentation SP content in median eminence was lower than in dioestrus. This fact indicates the possibility of SP involvement in the control of cyclic LH-RH release from hypothalamus.

Substance P in ovarian carcinoid

A high content of substance P (124 ng/g wet tissue) was demonstrated by radioimmunoassay in lymph node metastases in a patient with bilateral ovarian carcinoid tumours. The plasma substance P level was elevated but urinary 5-hydroxyindoleacetic acid (5-HIAA) was low. It is suggested that, in some carcinoid patients, an elevated plasma substance P level may help diagnosis and follow-up when urinary 5-HIAA is normal.

Substance P in medullary carcinoma of the thyroid

High levels of substance P-like immunoreactivity were demonstrated by radioimmunoassay in the plasma and tumour of a patient with a medullary carcinoma of the thyroid.

Substance P plasma levels in pregnancy and in various clinical disorders

Using radioimmunoassay, immunoreactive SP (iSP) has been measured in the plasma of 162 hospital patients with various disorders and in the plasma of 67 pregnant women. In pregnancy, iSP was undetectable in 40% women as compared to 12% in other hospital patients. The mean iSP plasma level in pregnancy was 37.8 +/- 4.6 (SEM) as compared to 77.1 +/- 4.9 (SEM) pg/ml in other hospital patients. The results support earlier observations based on bioassay, suggesting that the blood of pregnant women contains higher concentrations of a SP-inactivating factor. Of the hospital patients, elevated levels of iSP were found in patients with chronic leukaemia, in one patient with a basaloid carcinoma of the anus, and in one patient with toxic liver damage and pancreatic insufficiency. No correlation was found between thyroid function and iSP plasma levels. ISP plasma levels in various gastrointestinal disorders were similar to those found in normal subjects.