Significance of Antibody to Hepatitis B Core Antigen in a Hemodialysis Unit

Serum hepatitis B surface antigen (HB_sAg), antibody to HB_sAg (anti-HB_s) and antibody to hepatitis B core antigen (anti-HB_c) were determined serially in patients and staff in a hemodialysis unit. A low prevalence of HB_sAg (2.8 percent) was found. However, in patients without HB_sAg, anti-HB_c alone was present in 9.2 percent, and coexistent anti-HB_s and anti-HB_c in 19.2 percent. In persons with anti-HB_c only, the levels of anti-HB_c correlate positively with abnormal results on liver function studies (LFS). In all subjects with abnormal LFS findings, anti-HB_c levels were greater than 6.04 radioimmunoassay (RIA) units. In subjects with both anti-HB_s and anti-HB_c, all five subjects with higher anti-HB_c relative levels had abnormal LFS results and all subjects with normal LFS results had higher anti-HB_s relative levels. Along with other recent reports in the literature, these findings suggest a hepatitis B prevalence in this hemodialysis unit far in excess of that anticipated on the basis of HB_sAg prevalence.     

Tolerance to hepatitis B antigen: a hypothesis for its termination with 'immune-RNA'

Immunologic tolerance to hepatitis B antigen, evidenced by a lack of specific cellular and humoral immune response to HB_sAg, produces a chronic carrier state which serves as an epidemiologic reservoir for the transmission of viral hepatitis type B. It is proposed that cell-mediated immunity transferred with immune-RNA may serve to terminate immunologic tolerance to hepatitis B antigen and abolish the carrier state. The efficacy and safety of ‘immune-RNA’ administration to chronic carriers can be validated by leukocyte migration inhibition techniques $\text{in vitro}$ and in HB_sAg positive chimpanzees $\text{in vivo}$.     

A double-blind evaluation of transfer factor therapy of HBsAg-positive chronic aggressive hepatitis: preliminary report of efficacy.

A controlled, prospective, double-blind trial of transfer factor in chronic aggressive hepatitis was carried out. This report presents the results obtained from study of the nine HB_sAg-positive subjects who were included in the trial. Transfer factor was prepared from adults who had recovered from acute hepatitis B or from acute non-B viral hepatitis and was administered to five HB_sAg-positive subjects. Four HB_sAg-seropositive subjects received placebo. Percutaneous liver biopsy was performed at the beginning and at the conclusion of the 10-week study period; biochemical and clinical parameters were monitored throughout. Cell-mediated immunity was assessed at the beginning and at the end of the study period. Four of five transfer factor recipients showed moderate or marked improvement in hepatic histology, clinical status, and serum transaminase levels, while none of four placebo recipients demonstrated improvement. The difference in response between the two groups was significant (P = 0.048). No consistent changes in in vivo or in vitro correlates of cell-mediated immunity were demonstrated. No adverse effects were noted among transfer factor recipients. These data suggest that transfer factor may be of benefit in chronic aggressive hepatitis associated with HB_sAg. Additional studies appear to be indicated to delineate the mode of action of transfer factor as well as the role that such immunotherapy should play in the management of patients with this disorder.     

The duality of fractals: roughness and self-similarity

The fractal dimension (D _HB) is an interesting metrics because it is supposed to quantify by a single value, scale independence and roughness of ecological objects. However, we show here that those two properties may be quantified by a single dimension only in some specific cases. In general, a non-integer D _HB quantifies only the roughness, and self-similarity needs to be evidenced or postulated by other means. Second, we revisit some aspects of the practical estimation of D _HB. We recommend the use of madogram instead of variogram for estimations based on geostatistics. We propose a simplification of its estimation for 2D fields and discuss its possible relationship with self-similarity. We finally underline the problem of scale and resolution. Field data recorded during a scientific acoustic survey on the North Sea herring are used for illustrations. The paper concludes on a synthesis of practical recommendations to ecologists when using fractal dimension.     

Investigation of the Application of miR10b and miR135b in the Identification of Semen Stains

To evaluate the identification method using the microRNA markers miR10b and miR135b to distinguish semen stains from menstrual blood, peripheral blood, vaginal fluid and so on body fluid stains. The expression levels of miR10b and miR35b in semen stains and menstrual blood and so on were detected utilizing a real-time quantitative PCR technique with a specific fluorescence-labeled TaqMan probe. RNU6b was used as the internal reference gene; the difference in their expression was analyzed, and the specificity, sensitivity, and detection capability of the techniques were evaluated. The expression of miR10b and miR135b in semen stains was significantly higher than that of other body fluid stains, with a mean value of ΔCт from-6 to-7. However, it ranged from-2 to-4 for other body fluid stains. The initial criteria for judging which semen stains can be identified were determined by analyzing the research results. When the threshold value was set to 0.04, the C_T value could be detected in the target genes miR10b, miR135b and in the internal reference gene RNU6b, and C_T values are<40, ΔC_T[10b-U6]<-5.5, and ΔC_T[135b-U6]<-6, respectively, and the semen stain could be identified. The expression levels of miR10b and miR135b are higher in semen with strong tissue specificity; thus, they can be used to differentiate semen stains from other body fluid stains in forensic science.     

Viral Hepatitis: Problems of Incidence and Control in Military Personnel

(A) Hepatitis B virus (HBV) is now the major cause of infectious viral hepatitis in U.S. military personnel and probably also in the civilian population over 15 years of age. (B) The incidence of icteric, viral hepatitis is much higher in U.S. military personnel than in comparable age groups in the civilian population. The 17-to 20-year-old enlisted men show the highest rates. (C) In parts of the world (e.g., U.S.A., Germany) where most of the inapparent infection is caused by the adw subtype of HBV, most of the acute clinical disease is caused by the ayw subtype. In the U.S.A. and Germany, 95% or more of HB_s Ag isolates from U.S. military personnel with acute hepatitis is ayw. (D) It may be many years before one can expect to have sufficient data for a decision as to the possible availability of an effective HBV vaccine. Accordingly, a decision is urgently needed regarding either the immediate use of the best practically available hepatitis immune gamma globulin, that can be prepared by modern techniques, for the prevention of hepatitis in U.S. military personnel or postponement of such use until an adequate and properly controlled trial can be carried out in active duty military personnel in an area of high incidence.     

Population sizes,HIV prevalence,and HIV prevention among men who paid for sex in sub-Saharan Africa (2000–2020): A meta-analysis of 87 population-based surveys

BackgroundKey populations, including sex workers, are at high risk of HIV acquisition and transmission. Men who pay for sex can contribute to HIV transmission through sexual relationships with both sex workers and their other partners. To characterize the population of men who pay for sex in sub-Saharan Africa (SSA), we analyzed population size, HIV prevalence, and use of HIV prevention and treatment.Methods and findingsWe performed random-effects meta-analyses of population-based surveys conducted in SSA from 2000 to 2020 with information on paid sex by men. We extracted population size, lifetime number of sexual partners, condom use, HIV prevalence, HIV testing, antiretroviral (ARV) use, and viral load suppression (VLS) among sexually active men. We pooled by regions and time periods, and assessed time trends using meta-regressions. We included 87 surveys, totaling over 368,000 male respondents (15–54 years old), from 35 countries representing 95% of men in SSA. Eight percent (95% CI 6%–10%; number of surveys [N_s] = 87) of sexually active men reported ever paying for sex. Condom use at last paid sex increased over time and was 68% (95% CI 64%–71%; N_s = 61) in surveys conducted from 2010 onwards. Men who paid for sex had higher HIV prevalence (prevalence ratio [PR] = 1.50; 95% CI 1.31–1.72; N_s = 52) and were more likely to have ever tested for HIV (PR = 1.14; 95% CI 1.06–1.24; N_s = 81) than men who had not paid for sex. Men living with HIV who paid for sex had similar levels of lifetime HIV testing (PR = 0.96; 95% CI 0.88–1.05; N_s = 18), ARV use (PR = 1.01; 95% CI 0.86–1.18; N_s = 8), and VLS (PR = 1.00; 95% CI 0.86–1.17; N_s = 9) as those living with HIV who did not pay for sex. Study limitations include a reliance on self-report of sensitive behaviors and the small number of surveys with information on ARV use and VLS.ConclusionsPaying for sex is prevalent, and men who ever paid for sex were 50% more likely to be living with HIV compared to other men in these 35 countries. Further prevention efforts are needed for this vulnerable population, including improved access to HIV testing and condom use initiatives. Men who pay for sex should be recognized as a priority population for HIV prevention.

Caroline Hodgins and colleagues investigate the HIV prevalence, population sizes, and HIV prevention among men who paid for sex in sub-Saharan Africa (2000-2020).     

Identification of forensically relevant body fluids using a panel of differentially expressed microRNAs

The serology-based methods routinely used in forensic casework for the identification of biological fluids are costly in terms of time and sample and have varying degrees of sensitivity and specificity. Recently, the use of a molecular genetics-based approach using messenger RNA (mRNA) profiling has been proposed to supplant conventional methods for body fluid identification. However, the size of the amplification products used in these mRNA assays (∼ 200-300 nt) might not be ideal for use with degraded or compromised samples frequently encountered in forensic casework. Recently, there has been an explosion of interest in a novel class of small noncoding RNAs, microRNAs (miRNAs, ∼20-25 bases in length), with numerous published studies reporting that some miRNAs are expressed in a tissue-specific manner. In this article, we provide the first comprehensive evaluation of miRNA expression in dried, forensically relevant biological fluids—blood, semen, saliva, vaginal secretions, and menstrual blood—in an attempt to identify putative body fluid-specific miRNAs. Most of the 452 human miRNAs tested (∼67% of the known miRNAome) were either expressed in multiple body fluids or not expressed at all. Nevertheless, we have identified a panel of nine miRNAs—miR451, miR16, miR135b, miR10b, miR658, miR205, miR124a, miR372, and miR412—that are differentially expressed to such a degree as to permit the identification of the body fluid origin of forensic biological stains using as little as 50 pg of total RNA. The miRNA-based body fluid identification assays were highly specific because the miRNA expression profile for each body fluid was different from that obtained from 21 human tissues. The results of this study provide an initial indication that miRNA profiling may provide a promising alternative approach to body fluid identification for forensic casework.     

The genetics of congenital amusia (tone deafness): a family-aggregation study

Congenital amusia (commonly known as “tone deafness”) is a lifelong impairment of music perception that affects 4% of the population. To estimate whether congenital amusia can be genetically transmitted, its prevalence was quantified by direct auditory testing of 71 members of 9 large families of amusic probands, as well as of 75 members of 10 control families. The results confirm that congenital amusia is expressed by a deficit in processing musical pitch but not musical time and also show that the pitch disorder has a hereditary component. In amusic families, 39% of first-degree relatives have the same cognitive disorder, whereas only 3% have it in the control families. The identification of multiplex families with a high relative risk of experiencing a musical pitch deficit (λ_s=10.8; 95% confidence interval 8–13.5) enables the mapping of genetic loci for hereditary amusia.     

Acclimation of the Hermatypic Coral Stylophora pistillata to Bright Light

Photoacclimation dynamics to bright light was studied in the symbiotic reef-building coral Stylophora pistillata. Coral colonies were collected from shallow shaded sites (2 m, 40–20% PAR_s) from a fringing reef at Sesoko Island, Okinawa, Japan. Outer branches were broken off from the colonies and placed in an outdoor aquarium until the start of the experiments. After maintenance of the branches in an aquarium under a light intensity of 30% PAR_s for 30 days (experiment 1) or for 90 days (experiment 2), the samples were exposed to 95% PAR_s for 120 days in the same aquarium. The population density of zooxanthellae, chlorophyll concentration, locations of zooxanthellae, proliferating zooxanthellae frequency (PZF), and degrading zooxanthellae frequency (DZF) were examined. It was shown that after acclimation of coral branches to bright light, the population density of zooxanthellae, chlorophyll concentration calculated per 1000 polyps, and chlorophyll concentration in zooxanthellae decreased. The size of zooxanthellae significantly decreased. A decrease in the population density of zooxanthellae was detected by the eighth day of acclimation, and stabilization in the density of the symbionts occurred in the period from the 40th to the 60th day of the experiment. The chlorophyll concentration in zooxanthellae significantly decreased by the second day of exposure to bright light and stabilized by the fourth day. The PZF level sharply dropped on the second day, while the DZF level sharply increased and was higher than the PZF level for 40 days of exposure to bright light. We conclude, therefore, that the population density of zooxanthellae is regulated by the rates of two processes: cell division and the cell degradation.     

ds-erythro-2-amino-3,4-dihydroxybutanoic acid,a constituent in the edible mushroom,lyophyllum ulmarium

An unusual amino acid occurring in the fruiting bodies of Lyophyllum ulmarium was identified as d_s-erythro- 2-amino-3,4-dihydroxybutanoic acid, which is a compound found for the first time in biological materials.     

Frequency-domain order parameters for the burst and spike synchronization transitions of bursting neurons

We are interested in characterization of synchronization transitions of bursting neurons in the frequency domain. Instantaneous population firing rate (IPFR) R(t), which is directly obtained from the raster plot of neural spikes, is often used as a realistic collective quantity describing population activities in both the computational and the experimental neuroscience. For the case of spiking neurons, a realistic time-domain order parameter, based on R(t), was introduced in our recent work to characterize the spike synchronization transition. Unlike the case of spiking neurons, the IPFR R(t) of bursting neurons exhibits population behaviors with both the slow bursting and the fast spiking timescales. For our aim, we decompose the IPFR R(t) into the instantaneous population bursting rate R_b(t) (describing the bursting behavior) and the instantaneous population spike rate R_s(t) (describing the spiking behavior) via frequency filtering, and extend the realistic order parameter to the case of bursting neurons. Thus, we develop the frequency-domain bursting and spiking order parameters which are just the bursting and spiking “coherence factors” β_b and β_s of the bursting and spiking peaks in the power spectral densities of R_b and R_s (i.e., “signal to noise” ratio of the spectral peak height and its relative width). Through calculation of β_b and β_s, we obtain the bursting and spiking thresholds beyond which the burst and spike synchronizations break up, respectively. Consequently, it is shown in explicit examples that the frequency-domain bursting and spiking order parameters may be usefully used for characterization of the bursting and the spiking transitions, respectively.     

Significance of Population Size on the Fixation of Nonsynonymous Mutations in Genes Under Varying Levels of Selection Pressure

Previous studies observed a higher ratio of divergences at nonsynonymous and synonymous sites (ω = d_N/d_S) in species with a small population size compared to that estimated for those with a large population size. Here we examined the theoretical relationship between ω, effective population size (N_e), and selection coefficient (s). Our analysis revealed that when purifying selection is high, ω of species with small N_e is much higher than that of species with large N_e. However the difference between the two ω reduces with the decline in selection pressure (s → 0). We examined this relationship using primate and rodent genes and found that the ω estimated for highly constrained genes of primates was up to 2.9 times higher than that obtained for their orthologous rodent genes. Conversely, for genes under weak purifying selection the ω of primates was only 17% higher than that of rodents. When tissue specificity was used as a proxy for selection pressure we found that the ω of broadly expressed genes of primates was up to 2.1-fold higher than that of their rodent counterparts and this difference was only 27% for tissue specific genes. Since most of the nonsynonymous mutations in constrained or broadly expressed genes are deleterious, fixation of these mutations is influenced by N_e. This results in a higher ω of these genes in primates compared to those from rodents. Conversely, the majority of nonsynonymous mutations in less-constrained or tissue-specific genes are neutral or nearly neutral and therefore fixation of them is largely independent of N_e, which leads to the similarity of ω in primates and rodents.     

Distribution of Gene Frequency as a Test of the Theory of the Selective Neutrality of Polymorphisms

The variation in gene frequency among populations or between generations within a population is a result of breeding structure and selection. But breeding structure should affect all loci and alleles in the same way. If there is significant heterogeneity between loci in their apparent inbreeding coefficients F=s_p²/p(1-p), this heterogeneity may be taken as evidence for selection. We have given the statistical properties of F and shown how tests of heterogeneity can be made. Using data from human populations we have shown highly significant heterogeneity in F values for human polymorphic genes over the world, thus demonstrating that a significant fraction of human polymorphisms owe their current gene frequencies to the action of natural selection. We have also applied the method to temporal variation within a population for data on Dacus oleae and have found no significant evidence of selection.     

The Added and Interpretative Value of CGM-Derived Parameters in Type 1 Diabetes Depends on the Level of Glycemic Control

ObjectiveIn type 1 diabetes mellitus (T1DM) management, continuous glucose monitoring (CGM)-derived parameters can provide additional insights, with time in range (TIR) and other parameters reflecting glycemic control and variability being put forward. This study aimed to examine the added and interpretative value of the CGM-derived indices TIR and coefficient of variation (CV%) in T1DM patients stratified according to their level of glycemic control by means of HbA1C.MethodsT1DM patients with a minimum disease duration of 10 years and without known macrovascular disease were enrolled. Patients were equipped with a blinded CGM device for 7 days. TIR and time spent in hypoglycemia and hyperglycemia were determined, and CV% was used as a parameter for glycemic variability. Pearson (r) and Spearman correlations (r_s) and a regression analysis were used to examine associations.ResultsNinety-five patients (age: 45 ± 10 years; HbA1C level: 7.7% ± 0.8% [61 ± 7 mmol/mol]) were included (mean blood glucose [MBG]: 159 ± 31 mg/dL; TIR: 55.8% ± 14.9%; CV%: 43.5% ± 7.8%) and labeled as having good (HbA1C level ≤7% [≤53 mmol/mol]; n = 20), moderate (7%-8%; n = 44), or poor (>8% [>64 mmol/mol]; n = 31) glycemic control. HbA1C was significantly associated with MBG (r_s = 0.48, P < .001) and time spent in hyperglycemia (total: r_s = 0.52; level 2: r = 0.46; P < .001) but not with time spent in hypoglycemia and CV%, even after an analysis of the HbA1C subgroups. Similarly, TIR was negatively associated with HbA1C (r = −0.53; P < .001), MBG (r_s = −0.81; P < .001), and time spent in hyperglycemia (total: r_s = −0.90; level 2: r_s = −0.84; P < .001) but not with time in hypoglycemia. The subgroup analyses, however, showed that TIR was associated with shorter time spent in level-2 hypoglycemia in patients with good (r_s = −0.60; P = .007) and moderate (r_s = −0.25; P = .047) glycemic control. In contrast, CV% was strongly positively associated with time in hypoglycemia (total: r_s = 0.78; level 2: r_s = 0.76; P < .001) but not with TIR or time in hyperglycemia in the entire cohort, although the subgroup analyses showed that TIR was negatively associated with CV% in patients with good glycemic control (r = −0.81, P < .001) and positively associated in patients with poor glycemic control (r = +0.47; P < .01).ConclusionThe CGM-derived metrics TIR and CV% are related to clinically important situations, TIR being strongly dependent on hyperglycemia and CV% being reflective of hypoglycemic risk. However, the interpretation and applicability of TIR and CV% and their relationship depends on the level of glycemic control of the individual patient, with CV% generally adding less clinically relevant information in those with poor control. This illustrates the need for further research and evaluation of composite measures of glycemic control in T1DM.     

Analyzing Illumina Gene Expression Microarray Data from Different Tissues: Methodological Aspects of Data Analysis in the MetaXpress Consortium

Microarray profiling of gene expression is widely applied in molecular biology and functional genomics. Experimental and technical variations make meta-analysis of different studies challenging. In a total of 3358 samples, all from German population-based cohorts, we investigated the effect of data preprocessing and the variability due to sample processing in whole blood cell and blood monocyte gene expression data, measured on the Illumina HumanHT-12 v3 BeadChip array.Gene expression signal intensities were similar after applying the log₂ or the variance-stabilizing transformation. In all cohorts, the first principal component (PC) explained more than 95% of the total variation. Technical factors substantially influenced signal intensity values, especially the Illumina chip assignment (33–48% of the variance), the RNA amplification batch (12–24%), the RNA isolation batch (16%), and the sample storage time, in particular the time between blood donation and RNA isolation for the whole blood cell samples (2–3%), and the time between RNA isolation and amplification for the monocyte samples (2%). White blood cell composition parameters were the strongest biological factors influencing the expression signal intensities in the whole blood cell samples (3%), followed by sex (1–2%) in both sample types. Known single nucleotide polymorphisms (SNPs) were located in 38% of the analyzed probe sequences and 4% of them included common SNPs (minor allele frequency >5%). Out of the tested SNPs, 1.4% significantly modified the probe-specific expression signals (Bonferroni corrected p-value<0.05), but in almost half of these events the signal intensities were even increased despite the occurrence of the mismatch. Thus, the vast majority of SNPs within probes had no significant effect on hybridization efficiency.In summary, adjustment for a few selected technical factors greatly improved reliability of gene expression analyses. Such adjustments are particularly required for meta-analyses.     

Empirical Distributions of F ST from Large-Scale Human Polymorphism Data

Studies of the apportionment of human genetic variation have long established that most human variation is within population groups and that the additional variation between population groups is small but greatest when comparing different continental populations. These studies often used Wright’s F _ST that apportions the standardized variance in allele frequencies within and between population groups. Because local adaptations increase population differentiation, high-F _ST may be found at closely linked loci under selection and used to identify genes undergoing directional or heterotic selection. We re-examined these processes using HapMap data. We analyzed 3 million SNPs on 602 samples from eight worldwide populations and a consensus subset of 1 million SNPs found in all populations. We identified four major features of the data: First, a hierarchically F _ST analysis showed that only a paucity (12%) of the total genetic variation is distributed between continental populations and even a lesser genetic variation (1%) is found between intra-continental populations. Second, the global F _ST distribution closely follows an exponential distribution. Third, although the overall F _ST distribution is similarly shaped (inverse J), F _ST distributions varies markedly by allele frequency when divided into non-overlapping groups by allele frequency range. Because the mean allele frequency is a crude indicator of allele age, these distributions mark the time-dependent change in genetic differentiation. Finally, the change in mean-F _ST of these groups is linear in allele frequency. These results suggest that investigating the extremes of the F _ST distribution for each allele frequency group is more efficient for detecting selection. Consequently, we demonstrate that such extreme SNPs are more clustered along the chromosomes than expected from linkage disequilibrium for each allele frequency group. These genomic regions are therefore likely candidates for natural selection.     

Neuroendocrine heart and hypothalamus

Data on the endocrine heart—neurosecretory cells of heart, producing coronarydilatory, metabolically active glycopeptides with physico-chemical and biological properties similar to those of previously discovered cardioactive hypothalamic neurohormones—are summarized. Heart hormones participate in both local and distant regulation of heart metabolism and function. Formation and action of these heart hormones is closely related to hypothalamic cardioactive neurohormones K, C, and G and their protein precursors. Neurohormones from heart and hypothalamus comprise a system of neurohumoral connections between these two organs. A possible role of APUD cells in the generation of a number of heart peptides and glycopeptides exerting hormonal activity is discussed.Abbreviations Used NC Neurohormone C - NK Neurohormone K - NC-H Hypothalamic NC - NK-H Hypothalamic NK - PC-NC NC cleaved from protein-carrier - PC-NK NK cleaved from protein-carrier - BB-NC Brain blood NC - BB-NK Brain blood NK - H₁ Substrate 1 from heart - H₂ Substrate 2 from heart - H₃ Substrate 3 from heart - HB₁ Substrate 1 from heart blood - HB₂ Substrate 2 from heart blood - PC-H₁ H₁ cleaved from protein-carrier - PC-H₂ H₂ cleaved from protein-carrier - PC-H₃ H₃ cleaved from protein-carrier - PC-CC Coronaroconstrictory substance cleaved from protein-carrier - GPG Gomori-positive granules - MLC Mast-like cells     

Detection of Diffusion Heterogeneity in Single Particle Tracking Trajectories Using a Hidden Markov Model with Measurement Noise Propagation

We develop a Bayesian analysis framework to detect heterogeneity in the diffusive behaviour of single particle trajectories on cells, implementing model selection to classify trajectories as either consistent with Brownian motion or with a two-state (diffusion coefficient) switching model. The incorporation of localisation accuracy is essential, as otherwise false detection of switching within a trajectory was observed and diffusion coefficient estimates were inflated. Since our analysis is on a single trajectory basis, we are able to examine heterogeneity between trajectories in a quantitative manner. Applying our method to the lymphocyte function-associated antigen 1 (LFA-1) receptor tagged with latex beads (4 s trajectories at 1000 frames s⁻¹), both intra- and inter-trajectory heterogeneity were detected; 12–26% of trajectories display clear switching between diffusive states dependent on condition, whilst the inter-trajectory variability is highly structured with the diffusion coefficients being related by D ₁ = 0.68D ₀ − 1.5 × 10⁴ nm² s⁻¹, suggestive that on these time scales we are detecting switching due to a single process. Further, the inter-trajectory variability of the diffusion coefficient estimates (1.6 × 10² − 2.6 × 10⁵ nm² s⁻¹) is very much larger than the measurement uncertainty within trajectories, suggesting that LFA-1 aggregation and cytoskeletal interactions are significantly affecting mobility, whilst the timescales of these processes are distinctly different giving rise to inter- and intra-trajectory variability. There is also an ‘immobile’ state (defined as D < 3.0 × 10³ nm² s⁻¹) that is rarely involved in switching, immobility occurring with the highest frequency (47%) under T cell activation (phorbol-12-myristate-13-acetate (PMA) treatment) with enhanced cytoskeletal attachment (calpain inhibition). Such ‘immobile’ states frequently display slow linear drift, potentially reflecting binding to a dynamic actin cortex. Our methods allow significantly more information to be extracted from individual trajectories (ultimately limited by time resolution and time-series length), and allow statistical comparisons between trajectories thereby quantifying inter-trajectory heterogeneity. Such methods will be highly informative for the construction and fitting of molecule mobility models within membranes incorporating aggregation, binding to the cytoskeleton, or traversing membrane microdomains.