Video2Haptics: Converting Video Motion to Dynamic Haptic Feedback with Bio-Inspired Event Processing

In cinematic VR applications, haptic feedback can significantly enhance the sense of reality and immersion for users. The increasing availability of emerging haptic devices opens up possibilities for future cinematic VR applications that allow users to receive haptic feedback while they are watching videos. However, automatically rendering haptic cues from real-time video content, particularly from video motion, is a technically challenging task. In this paper, we propose a novel framework called "Video2Haptics" that leverages the emerging bio-inspired event camera to capture event signals as a lightweight representation of video motion. We then propose efficient event-based visual processing methods to estimate force or intensity from video motion in the event domain, rather than the pixel domain. To demonstrate the application of Video2Haptics, we convert the estimated force or intensity to dynamic vibrotactile feedback on emerging haptic gloves, synchronized with the corresponding video motion. As a result, Video2Haptics allows users not only to view the video but also to perceive the video motion concurrently. Our experimental results show that the proposed event-based processing methods for force and intensity estimation are one to two orders of magnitude faster than conventional methods. Our user study results confirm that the proposed Video2Haptics framework can considerably enhance the users' video experience.

A Q-learning-based routing scheme for smart air quality monitoring system using flying ad hoc networks

Air pollution has changed ecosystem and atmosphere. It is dangerous for environment, human health, and other living creatures. This contamination is due to various industrial and chemical pollutants, which reduce air, water, and soil quality. Therefore, air quality monitoring is essential. Flying ad hoc networks (FANETs) are an effective solution for intelligent air quality monitoring and evaluation. A FANET-based air quality monitoring system uses unmanned aerial vehicles (UAVs) to measure air pollutants. Therefore, these systems have particular features, such as the movement of UAVs in three-dimensional area, high dynamism, quick topological changes, constrained resources, and low density of UAVs in the network. Therefore, the routing issue is a fundamental challenge in these systems. In this paper, we introduce a Q-learning-based routing method called QFAN for intelligent air quality monitoring systems. The proposed method consists of two parts: route discovery and route maintenance. In the part one, a Q-learning-based route discovery mechanism is designed. Also, we propose a filtering parameter to filter some UAVs in the network and restrict the search space. In the route maintenance phase, QFAN seeks to detect and correct the paths near to breakdown. Moreover, QFAN can quickly identify and replace the failed paths. Finally, QFAN is simulated using NS2 to assess its performance. The simulation results show that QFAN surpasses other routing approaches with regard to end-to-end delay, packet delivery ratio, energy consumption, and network lifetime. However, communication overhead has been increased slightly in QFAN.

First-in-human phase 1 study of the anti-TIGIT antibody vibostolimab as monotherapy or with pembrolizumab for advanced solid tumors, including non-small cell lung cancer

BACKGROUND

In this first-in-human phase 1 study, we investigated the safety and efficacy of the anti-TIGIT antibody vibostolimab as monotherapy or in combination with pembrolizumab.

METHODS

Part A enrolled patients with advanced solid tumors and part B enrolled patients with non-small cell lung cancer (NSCLC). Patients received vibostolimab 2.1-700 mg alone or with pembrolizumab 200 mg in part A and vibostolimab 200 mg alone or with pembrolizumab 200 mg in part B. Primary end points were safety and tolerability. Secondary end points included pharmacokinetics and objective response rate (ORR) per RECIST v1.1.

RESULTS

Part A enrolled 76 patients (monotherapy, 34; combination therapy, 42). No dose-limiting toxicities were reported. Across doses, 56% of patients receiving monotherapy and 62% receiving combination therapy had treatment-related adverse events (TRAEs); grade 3-4 TRAEs occurred in 9% and 17% of patients, respectively. The most common TRAEs were fatigue (15%) and pruritus (15%) with monotherapy and pruritus (17%) and rash (14%) with combination therapy. Confirmed ORR was 0% with monotherapy and 7% with combination therapy. In part B, 39 patients had anti-PD-1/PD-L1-naïve NSCLC (all received combination therapy) and 67 had anti-PD-1/PD-L1-refractory NSCLC (monotherapy, 34; combination therapy, 33). In patients with anti-PD-1/PD-L1-naive NSCLC: 85% had TRAEs-the most common were pruritus (38%) and hypoalbuminemia (31%); confirmed ORR was 26%, with responses occurring in both PD-L1-positive and PD-L1-negative tumors. In patients with anti-PD-1/PD-L1‒refractory NSCLC: 56% receiving monotherapy and 70% receiving combination therapy had TRAEs-the most common were rash and fatigue (21% each) with monotherapy and pruritus (36%) and fatigue (24%) with combination therapy; confirmed ORR was 3% with monotherapy and 3% with combination therapy.

CONCLUSION

Vibostolimab plus pembrolizumab was well tolerated and demonstrated antitumor activity in patients with advanced solid tumors, including patients with advanced NSCLC.

Deep learning in generating radiology reports: A survey

Substantial progress has been made towards implementing automated radiology reporting models based on deep learning (DL). This is due to the introduction of large medical text/image datasets. Generating radiology coherent paragraphs that do more than traditional medical image annotation, or single sentence-based description, has been the subject of recent academic attention. This presents a more practical and challenging application and moves towards bridging visual medical features and radiologist text. So far, the most common approach has been to utilize publicly available datasets and develop DL models that integrate convolutional neural networks (CNN) for image analysis alongside recurrent neural networks (RNN) for natural language processing (NLP) and natural language generation (NLG). This is an area of research that we anticipate will grow in the near future. We focus our investigation on the following critical challenges: understanding radiology text/image structures and datasets, applying DL algorithms (mainly CNN and RNN), generating radiology text, and improving existing DL based models and evaluation metrics. Lastly, we include a critical discussion and future research recommendations. This survey will be useful for researchers interested in DL, particularly those interested in applying DL to radiology reporting.

Evaluation of safety and efficacy of p53MVA vaccine combined with pembrolizumab in patients with advanced solid cancers

BACKGROUND

Vaccination of cancer patients with p53-expressing modified vaccinia Ankara virus (p53MVA) has shown in our previous studies to activate p53-reactive T cells in peripheral blood but without immediate clinical benefit. We hypothesized that the immunological responses to p53MVA vaccine may require additional immune checkpoint blockade to achieve clinically beneficial levels. We therefore conducted a phase I trial evaluating the combination of p53MVA and pembrolizumab (anti-PD-1) in patients with advanced solid tumors.

PATIENTS AND METHODS

Eleven patients with advanced breast, pancreatic, hepatocellular, or head and neck cancer received up to 3 triweekly vaccines in combination with pembrolizumab given concurrently and thereafter, alone at 3-week intervals until disease progression. The patients were assessed for toxicity and clinical response. Correlative studies analyzed p53-reactive T cells and profile of immune function gene expression.

RESULTS

We observed clinical responses in 3/11 patients who remained with stable disease for 30, 32, and 49 weeks. Two of these patients showed increased frequencies and persistence of p53-reactive CD8+ T cells and elevation of expression of multiple immune response genes. Borderline or undetectable p53-specific T cell responses in 7/11 patients were related to no immediate clinical benefit. The first study patient had a grade 5 fatal myocarditis. After the study was amended for enhanced cardiac monitoring, no additional cardiac toxicities were noted.

CONCLUSION

We have shown that the combination of p53MVA vaccine with pembrolizumab is feasible, safe, and may offer clinical benefit in select group of patients that should be identified through further studies.

Ureteroscopy in the diagnosis of upper tract transitional cell cancer: a 10-year experience providing outcome data for informed consent

PURPOSE

The aim of the study was to assess the effectiveness of ureteroscopy and biopsy in the diagnosis and management of upper tract urothelial carcinoma.

METHODS

We retrospectively collated data from pathology, radiology and operating theatre data sets from two large UK hospitals. During the 10-year period examined, 160 patients underwent ureteroscopy prior to nephro-ureterectomy (NU)/distal ureterectomy (DU).

RESULTS

Of the 160 patients identified, 140 were ureteroscopically evaluated and biopsied, 104 (74.3%) had positive biopsies, 5 (3.6%) had negative biopsies and 31 (22.1%) had nondiagnostic biopsies.One hundred and forty patients of 160 (88.8%) resulted in positive findings as a result of their ureteroscopy [positive biopsy/positive operative cytology/visible upper tract urothelial carcinoma (UTUC) at ureteroscopy)].A total of 108 patients had cytological samples sent for histological analysis where grade was able to be assessed at DU/NU. Of these samples, 35 had positive cytology, 58 had an abnormal result that was not diagnostic and 15 had negative cytology.Patients with positive biopsies had upstaging (58.4%) and/or upgrading (30.5%) of their initial ureteroscopic histology at NU/DU.The overall success rate of ureteroscopy for cancer diagnosis was 88.8%.

CONCLUSIONS

Upper tract endoscopy and biopsy yielded positive biopsy results in 74.3% of cases and confirmed a cancer diagnosis in 88.8%. Five patients had negative histology at biopsy, all of whom eventually underwent a NU/DU confirming cancer.

A phase I study of bortezomib and temozolomide in patients with advanced solid tumors

PURPOSE

The primary objective was to determine the maximum tolerated doses (MTDs) of the combination of bortezomib and temozolomide in patients with solid tumors. The secondary objective was to evaluate the pharmacokinetics (PK) of bortezomib with and without concurrent hepatic enzyme-inducing anticonvulsants (HEIAs).

METHODS

Bortezomib was administered on days 2, 5, 9, and 12; temozolomide on days 1-5 of a 28-day cycle. Dose escalation proceeded using a standard 3+3 design. Patients with primary or metastatic brain tumors were eligible and were stratified based on whether they were taking HEIAs or not.

RESULTS

Of the 25 patients enrolled, 22 were not taking HEIAs. MTDs were only given to patients not receiving HEIAs. Dose-limiting toxicities (DLTs) consisted of grade-3 constipation, hyponatremia, fatigue, elevated hepatic enzymes, and grade-4 neutropenia, thrombocytopenia, constipation, and abdominal pain. Stable disease (>8 weeks) was observed in 5 patients. Bortezomib systemic clearance (CL(sys)) on day 9 was 51% of the CL(sys) on day 2 (P < 0.01) Similarly, the normalized area under the concentration-time curve (norm AUC) on day 9 was 1.9 times the norm AUC on day 2 (P < 0.01). The median bortezomib CL(sys) on days 2 and 9 was significantly higher (P < 0.04) in patients taking HEIAs, and the median norm AUC was correspondingly lower (P < 0.04).

CONCLUSIONS

The MTDs for the combination of bortezomib and temozolomide in patients not taking HEIAs are 1.3 and 200 mg/m(2), respectively. The rate of bortezomib elimination in patients taking HEIAs was increased twofold. Additional trials are needed to better define the optimal dosing in such patients.

Phase I evaluation of lapatinib and everolimus in patients with advanced malignancies: Southwest Oncology Group trial S0528

3553

Background: Anti-tumor activity of Her inhibitors including lapatinib, an oral inhibitor of Her1 and Her 2, appears to correlate with their ability to down regulate PI3/Akt pathway. Everolimus, an oral inhibitor of mTOR, a serine/threonine kinase downstream of Akt, has shown enhanced efficacy when combined with Her inhibitors in pre-clinical studies. This phase I study is being conducted to determine the maximum tolerated dose (MTD) and pharmacokinetics (PK) of the combination of lapatinib and everolimus. Methods: Pts with advanced tumors, for which there was no effective therapy, were eligible. The study consists of two parts. In Part I dose escalation to define MTD was performed with both drugs being given together. MTD was defined by dose limiting toxicities (DLT) in the first cycle (each cycle is of 4 weeks duration). In Part II, PK of both drugs are being analyzed in patients treated at MTD and randomized to either cohort A- everolimus alone for a week followed by both drugs, or cohort B- lapatinib alone for a week followed by both drugs. 12 PK eligible pts will be accrued to each cohort to detect the influence of one drug over the other drug's PK. Results: 26 pts were enrolled in Part I of the study, 23 were evaluable for DLT. Median age- 63 (29–76); males/females- 20/6. Common tumors were breast (4), lung cancer (3), adenoid cystic (3). 79 cycles (median 2, range 1–15) have been administered to date. 6 pts developed DLTs: pneumonitis, rash, diarrhea, stomatitis (2), and fatigue (2). The MTD of the combination is lapatinib 1250mg and everolimus 5mg, daily. None of the pts had a response but 11 pts (2 liver, 1 breast, 1 renal, 1 sarcoma, 2 adenoid cystic, 1 melanoma, 1 bladder, 1 NSCLC, 1 colorectal) had stable disease for 8 weeks or longer. Conclusions: The MTD of the combination is lapatinib 1250 mg and everolimus 5 mg. The dose limiting toxicities observed were diarrhea, stomatitis and fatigue. Accrual to Part II is ongoing and pharmacokinetic analysis is pending.

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Massage intervention for promoting mental and physical health in infants aged under six months

BACKGROUND

Infant massage is increasingly being used in the community for low-risk babies and their primary care givers. Anecdotal claims suggest benefits for sleep, respiration, elimination and the reduction of colic and wind. Infant massage is also thought to reduce infant stress and promote positive parent-infant interaction.

OBJECTIVES

The aim of this review was to assess the effectiveness of infant massage in promoting infant physical and mental health in population samples.

SEARCH STRATEGY

Searches were undertaken of CENTRAL 2005 (Issue 3), MEDLINE (1970 to 2005), PsycINFO (1970 to 2005), CINAHL (1982 to 2005), EMBASE (1980 to 2005), and a number of other Western and Chinese databases.

SELECTION CRITERIA

Studies in which babies under the age of six months were randomised to an infant massage or a no-treatment control group, and utilising a standardised outcome measuring infant mental or physical development.

DATA COLLECTION AND ANALYSIS

Weighted and standardised mean differences and 95% confidence intervals are presented. Where appropriate the results have been combined in a meta-analysis using a random effects model.

MAIN RESULTS

Twenty-three studies were included in the review. One was a follow-up study and thirteen were included in a separate analysis due to concerns about the uniformly significant results and the lack of dropout. The results of nine studies providing primary data suggest that infant massage has no effect on growth, but provides some evidence suggestive of improved mother-infant interaction, sleep and relaxation, reduced crying and a beneficial impact on a number of hormones controlling stress. Results showing a significant impact on number of illnesses and clinic visits were limited to a study of Korean orphanage infants. There was no evidence of effects on cognitive and behavioural outcomes, infant attachment or temperament. The data from the 13 studies regarded to be at high risk of bias show uniformly significant benefits on growth, sleep, crying and bilirubin levels.

AUTHORS' CONCLUSIONS

The only evidence of a significant impact of massage on growth was obtained from a group of studies regarded to be at high risk of bias. There was, however, some evidence of benefits on mother-infant interaction, sleeping and crying, and on hormones influencing stress levels. In the absence of evidence of harm, these findings may be sufficient to support the use of infant massage in the community, particularly in contexts where infant stimulation is poor. Further research is needed, however, before it will be possible to recommend universal provision.

Oral cancer educational materials for the general public: 1998

OBJECTIVES

Previous studies have shown that US adults are not well informed about oral cancers and only 15 percent ever have had an oral cancer examination. This study sought to determine the quantity and adequacy of educational materials designed to inform or educate US adults about risks for, and signs and symptoms of, oral cancer and the need for an oral cancer examination.

METHODS

Letters requesting copies of oral cancer educational materials produced by the organization or agency--leaflets, fact sheets, pamphlets, videos, posters--were sent to 172 national and state organizations or agencies. To determine the adequacy of the items, a previously developed, tested, and used form based on current science was adapted for this study. In addition, the SMOG index was used to determine readability for printed items.

RESULTS

Seventy-seven percent or 132 of the selected organizations responded to queries. A total of 59 items were received that focused on or included the topic of oral cancer. Twenty of these 59 items focused specifically on oral cancer; the balance, on other topics, but mentioned oral cancer. The readability ranged from sixth to 13th grade.

CONCLUSIONS

This study demonstrates a dearth of educational materials about oral and pharyngeal cancers; most are written at too high a grade level for the general public. These findings may help to explain why the public is so uninformed about these neoplasms.

Biophysical and functional characterization of full-length, recombinant human tissue inhibitor of metalloproteinases-2 (TIMP-2) produced in Escherichia coli. Comparison of wild type and amino-terminal alanine appended variant with implications for the mechanism of TIMP functions

Matrix metalloproteinases (MMPs) function in the remodeling of the extracellular matrix that is integral for many normal and pathological processes. The tissue inhibitor of metalloproteinases family, including tissue inhibitor of metalloproteinases-2 (TIMP-2), regulates the activity of these multifunctional metalloproteinases. TIMP family members are proteinase inhibitors that contain six conserved disulfide bonds, one involving an amino-terminal cysteine residue that is critical for MMP inhibitor activity. TIMP-2 has been expressed in Escherichia coli, folded from insoluble protein, and functionally characterized. The wild type protein inhibited gelatinase A (MMP-2), whereas a variant with an alanine appended to the amino terminus (Ala+TIMP-2) was inactive. Removal of amino-terminal alanine by exopeptidase digestion restored protease inhibitor activity. This confirms the mechanistic importance of the amino-terminal amino group in the metalloproteinase inhibitory activity, as originally suggested from the x-ray structure of a complex of MMP-3 with TIMP-1 and a complex of TIMP-2 with MT-1-MMP. The Ala+TIMP-2 variant exhibited conformational, pro-MMP-2 complex formation and fibroblast growth modulating properties of the wild type protein. These findings demonstrate that Ala+TIMP-2 is an excellent biochemical tool for examining the specific role of MMP inhibition in the multiple functions ascribed to TIMPs.

Short-term vs long-term dexamethasone treatment: effects on rat diaphragm structure and function

The effects of dexamethasone treatment duration (2.5 vs 10 weeks) on diaphragm myosin heavy chain isoforms, fiber types, and contractile characteristics were studied in male rats. Compared with ad libitum-fed and pair-fed controls, dexamethasone significantly decreased body weight, costal diaphragm weight, and the relative expression of myosin heavy chain isoform MHC-2B. Compared with pair-fed controls, the effect on MHC-2B expression was greater after 10 weeks than after 2.5 weeks. Type I and type II costal diaphragm fiber atrophy occurred, and type II fiber atrophy was greater after 10 weeks. Costal diaphragm-specific forces were not affected significantly by dexamethasone, regardless of the treatment duration or control group comparison. Fatigue resistance indexes were increased significantly after long term treatment compared with pair-fed controls and after both short-term and long-term treatment compared with ad libitum-fed controls. In conclusion, the effects of dexamethasone on MHC isoform phenotype expression, fiber type costal diaphragm atrophy, and fatigue resistance were dependent on treatment duration, with greater effects after long-term (10 weeks) treatment.

Short- and long-term effects of testosterone on diaphragm in castrated and normal male rats

The effects of short- and long-term testosterone absence or treatment on the diaphragm were studied in castrated and sexually normal male rats. Compared with control rats (untreated normal males), testosterone absence or treatment did not significantly affect costal weight. In untreated castrated males, there were significant decreases in specific forces, type II fiber cross-sectional area, and myosin heavy chain (MHC) isoform 2B after 2.5 wk. In castrated males that received testosterone, there were significant increases in specific forces, type II total fiber proportional area, and relative expression of all adult diaphragm fast MHC isoforms (MHC-2all) after 2.5 wk. In normal males that received testosterone, the only significant finding was an increase in MHC-2B after 2.5 wk. Across all groups, there was close correlation between increases in maximum tetanic forces and MHC-2all. Changes in diaphragm function and composition were closely related to changes in serum testosterone levels at 2.5 wk. The lack of significant change in diaphragm function at 10 wk occurred despite changes in serum testosterone levels and diaphragm composition similar to those at 2.5 wk. These findings support our hypothesis that the effects of testosterone are dependent on basal circulating androgen levels and study duration.

In vivo T-cell clonal amplification at time of acute graft-versus-host disease

In a series of patients transplanted with HLA-matched allogeneic bone marrow grafts (alloBMT), we previously showed that a few T-cell receptor (TCR) V alpha and V beta gene segment transcripts were overexpressed in skin compared with blood at the time of acute graft-versus-host disease (aGVHD). Here, in one selected patient with overexpressed V beta 16 and V alpha 11 transcripts in skin, we analyzed the junctional variability of these transcripts in donor blood, patient blood, and skin collected at aGVHD onset. A unique junctional region sequence accounted for 81% of in frame V beta 16 transcripts (13 of 16) in skin and 59% (13 of 22) in patient blood. Similarly, two recurrent junctional region sequences were found in skin V alpha 11 transcripts, one accounting for 66% (21 of 32) and the other for 16% (5 of 32). These recurrences were also found in patient blood (36% and 15% of V alpha 11 transcripts, respectively). To extend our analysis, a polymerase chain reaction (PCR)-based method was used to precisely determine TCR beta transcript length in run-off reactions using uncloned bulk cDNA samples. All V beta-C beta PCR products analyzed in donor blood, as well as the majority of those analyzed in patient blood, included transcripts with highly diverse junctional region sizes. As expected from the sequence data, most V beta 16-C beta PCR products in skin and patient blood were of the same size (ie, same junctional region). In addition, V beta 3, V beta 5, and V beta 17 transcripts in skin were shown to display highly restricted size variability. The clonality of the V beta 16-C beta and V beta 17-C beta transcripts was further supported by the results of run-off reactions using 13 J beta specific primers. We have identified several recurrent TCR transcripts in skin, some of them also present in patient blood. These data support the view that several T-cell subpopulations are clonally expanded in vivo at the time of aGVHD onset in this case of related HLA-matched alloBMT.

Influence of human leukocyte antigen genes on TCR V gene segment frequencies

Human leukocyte antigen (HLA)-dependent selection mechanisms exerted during thymic maturation are supposed to be main contributing factors to the genetic predetermination of the TCR repertoire and may have a detectable effect on adult peripheral blood lymphocyte V segment frequencies. Here, we analyzed whether polymorphic or non-polymorphic HLA determinants are associated with selected expression of some V gene segment specificities. We first examined the reactivity of 17 V segment specific mAb on purified CD4+ and CD8+ cell fractions in 10 unrelated people. We found a significant overexpression of only three V segment products (V beta 2, V beta 5.1 and V beta 6.7) in CD4+ and none in CD8+ cell fractions in most individuals. Skewing of certain V beta segments by non-polymorphic HLA determinants (i.e. class II for CD4+ and class I for CD8+ cells) is therefore more limited (3/17) than previously thought. Considering the effects of polymorphic HLA determinants, we compared TCR V segment frequencies in HLA-identical siblings to sibling pairs who differ at one or both HLA haplotypes, using 13 V beta specific mAb. In pairwise comparisons, we found that the HLA complex had no detectable effect on TCR repertoire in five large families with multiple siblings. Together, these observations suggest that HLA-predicted selection mechanisms exerted during thymic maturation might not have a predominant influence shaping the TCR repertoire of normal adults.

TCR gene segments from at least one third of V alpha subfamilies rearrange at the delta locus

Using PCR and an experimentally validated V alpha subfamily-specific oligonucleotide panel (V alpha 1-w29), we have investigated whether the TCR delta chain may increase its combinatorial diversity by using V genes considered as alpha chain-specific. We show that at least 10 distinct human V alpha segments rearrange at the J delta locus, leading to scrambling of the two V gene repertoires. Fifty-five per cent of the V alpha/J delta transcripts characterized here were in frame. The 17 V alpha/C delta chains analysed included an extended CDR3 region with up to 18 aa encoded by the junctional region. In addition, a new J delta segment (J delta 4) has been characterized. Together, these findings demonstrate that combinatorial diversity in the human delta locus is larger than previously thought.

Rat brain hexokinase: further studies on the specificity of the hexose and hexose 6-phosphate binding sites

Based on the lack of correlation between the ability of various hexoses to serve as substrate and the ability of the corresponding hexose 6-phosphates to inhibit brain hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1), R. K. Crane and A. Sols (1954, J. Biol. Chem. 210, 597-606) proposed that this enzyme possesses two discrete sites capable of binding hexose moieties, one serving as the substrate binding site and a second, regulatory in function, to which inhibitory 6-phosphates bind. Subsequent work has provided further experimental support for this proposal. The pioneering work by Crane and Sols focused primarily on the specificity of these sites with respect to requirements for orientation of hydroxyl substituents at the various positions of the pyranose ring. The present study explores additional aspects of the specificity of these sites, namely, the effect of substitution of a sulfur atom in place of the oxygen in the pyranose ring on ability to serve as substrate or inhibitor, and the effect of modification in charge of the substituent at the 6-position on inhibitory effectiveness. 5-Thioglucose is a linear competitive (versus glucose) inhibitor of rat brain hexokinase, with a Ki of about 0.2 mM, and is a linear mixed inhibitor (versus ATP), with Ki values in this same range. 5-Thioglucose is not, however, readily phosphorylated by brain hexokinase. Thus, although 5-thioglucose binds with moderate affinity to the glucose binding site, it is not effectively used as a substrate of the enzyme. Inhibition of brain hexokinase by glucose 6-phosphate or its analogs has been found to require a dianionic substituent at the 6-position. The 6-fluorophosphate derivative and glucose 6-sulfate are poor inhibitors of the enzyme, and the Ki for inhibition by 1,5-anhydroglucitol 6-phosphate increases markedly at pH values below the pK of the 6-phosphate group, indicating that the monoanionic form is ineffective as an inhibitor. In contrast to the detrimental effect that substitution of the oxygen atom in the pyranose ring with a sulfur has on ability to serve as substrate, 5-thio analogs are considerably more effective as inhibitors, the Ki for inhibition by 5-thioglucose 6-phosphate being 10-fold lower than that seen with glucose 6-phosphate. This effect of the heteroatom substitution can partially offset the decreased inhibition resulting from monoanionic character at the 6-position, but the 6-fluorophosphate derivative of 5-thioglucose 6-phosphate still inhibits with a Ki about 1000-fold greater than that seen with 5-thioglucose 6-phosphate.(ABSTRACT TRUNCATED AT 400 WORDS)

Imuthiol influences on cytotoxic T cells and NK activity in +/+ and athymic nude BALB/c mice

The effects of imuthiol (sodium ditiocarb, DTC) on the expression of cytotoxic responses (CTL) and natural killer (NK) activity were evaluated in aged and young euthymic mice, and in nu/nu BALB/c mice. Imuthiol generated CTL and concomitantly reduced NK activity in nu/nu mice, suggesting that the agent can generate T cells in athymic nude animals. Treatment for up to 4 months augmented spleen NK and CTL activities in young or aged euthymic mice, but the generation of CTL in old animals was increased by long-term treatments better than by a single injection. The capacity of imuthiol to activate specific and nonspecific cytotoxic functions in euthymic mice may contribute to enhancement of resistance in vivo against transformed cells after treatment with this agent.

Circannual rhythm in natural killer activity and mitogen responsiveness of murine splenocytes

Seasonal variations were observed in murine splenic natural killer (NK) cell activity and also in murine lymphocyte responsiveness to mitogens, namely, concanavalin A, phytohemagglutinin, and lipopolysaccharide. The maximum and minimum splenic NK cell activities were observed in January-February and July-August, respectively. Conversely, maxima and minima of lymphoproliferative responses to all the three mitogens occurred in April-June and January-February, respectively. Such variations, when inferential statistics are used, appeared to be accounted for by circannual and other low-frequency (infradian) bioperiodicities. More specifically, the circannual rhythm in murine NK cell activity was demonstrated in data from a total of 356 mice collected over a period of 5 years. The various components of the immune system are characterized by a multifrequency time structure. The understanding of the organization of the immune system along the yearly scale may have bearings on that of the seasonal incidence of numerous infectious diseases and on the success/failure of immunotherapy.

In vivo immunopharmacological properties of tuftsin (Thr-Lys-Pro-Arg) and some analogues

Tuftsin (Thr-Lys-Pro-Arg) is part of the Fc fragment of a leukophilic IgG and is a stimulator of the phagocytic activity of macrophages and polymorphonuclear cells (PMN) when cleaved from its carrier molecule. Tuftsin was shown to stimulate in vitro all PMN and macrophage functions examined through binding to specific cell surface receptors. In the present work, we provide further evidence that synthetic tuftsin administered to mice may act as an immunomodulator and that its effects on immune functions may result from a primary action on macrophages. After i.v. injection at a dosage of 25 micrograms/mouse, tuftsin stimulated effector (phagocytosis) and regulatory (IL1 production) functions of macrophages and potentiated DTH reaction. Lymphocyte functions (proliferative response to mitogens, T cell-mediated cytotoxicity, IL2 and gamma IFN production) were depressed at times at which macrophage activities were maximally enhanced, suggesting that negative regulatory functions of these latter cells were also stimulated. Tuftsin analogues were synthetized representing substitution or derivatization of the threonyl residue. The relative potencies of these analogues in augmenting phagocytosis-induced chemiluminescence of macrophages were tuftsin greater than or equal to (Gly1)-tuftsin greater than for-tuftsin greater than (for-Met1)-tuftsin greater than (Met1)-tuftsin. Concerning potentiation of DTH reaction the order was (Gly1)-tuftsin greater than or equal to (for-Met1)tuftsin greater than tuftsin greater than (Met1)-tuftsin greater than for-tuftsin. In contrast to tuftsin, none of the analogues induced depression of spleen cell reactivity to mitogens. In addition, (for Met1)-tuftsin administration resulted in an increased production of IL2 and IFN by ConA-stimulated spleen cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Modifications of host defence mechanisms by an acute non-immunological inflammatory reaction

Mice developing an acute non-immunological inflammatory reaction were examined for modification of specific and non-specific defence mechanisms on the basis of previous observations that these animals displayed an increased resistance to bacterial and parasitic infections but an impaired resistance to neoplasia. Local acute inflammation was induced by injection into the pleural cavity of a non-antigenic, endotoxin-free irritant--calcium pyrophosphate microcrystals or low-molecular-weight dextran. Effector functions of macrophages at remote sites from the inflammatory focus were markedly stimulated. This was shown by: (a) an accelerated elimination of Listeria monocytogenes in the liver and spleen of mice with inflammation; (b) the acquisition of cytostatic activity for tumour cells by peritoneal macrophages; and (c) an enhancement of chemiluminescence emission and superoxide production in response to phagocytosis. Natural killer activity of spleen and peritoneal cells was stimulated in a biphasic manner. In contrast, cytolytic T cell differentiation upon in vitro immunization of spleen cells against allogeneic tumour cells was impaired. All these effects were observed very early (2 h) after the onset of inflammation and were still detectable at least 3 days after the inflammatory process had disappeared.

Multiple photon coincidence tomography

Coincidence scanning devices that measure the distribution of radioisotopes emitting multiple photons in nuclear cascade decays offer a possible supplementary approach to tomography in nuclear medicine. Design factors that serve to determine resolution, sensitivity, and statistical noise for the multiphoton coincidence linear scanner (MCLS), the total organ kinetic imaging monitor (TOKIM), and related systems have been well studied. Focused collimator coincidence scanner (FCCS) systems are capable of extremely high resolution--spherical cold lesions of less than 0.2 cu cm volume being easily detectable. Although FCCS scan speeds are too slow for imaging of large organs, scan times for small organs or for the rescanning of suspicious or ambigous regions appearing on conventional scans are well within practical clinical limits. In view of recent developments in the on-site cyclotron production of short-lived radioisotopes and the current interest in high resolution localization of neurologic receptors in vivo, FCCS systems may prove also to be of value in basic neurophysiologic studies.