Super-resolution time-resolved imaging using computational sensor fusion

Imaging across both the full transverse spatial and temporal dimensions of a scene with high precision in all three coordinates is key to applications ranging from LIDAR to fluorescence lifetime imaging. However, compromises that sacrifice, for example, spatial resolution at the expense of temporal resolution are often required, in particular when the full 3-dimensional data cube is required in short acquisition times. We introduce a sensor fusion approach that combines data having low-spatial resolution but high temporal precision gathered with a single-photon-avalanche-diode (SPAD) array with data that has high spatial but no temporal resolution, such as that acquired with a standard CMOS camera. Our method, based on blurring the image on the SPAD array and computational sensor fusion, reconstructs time-resolved images at significantly higher spatial resolution than the SPAD input, upsampling numerical data by a factor \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$12 \times 12$$\end{document}12×12, and demonstrating up to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$4 \times 4$$\end{document}4×4 upsampling of experimental data. We demonstrate the technique for both LIDAR applications and FLIM of fluorescent cancer cells. This technique paves the way to high spatial resolution SPAD imaging or, equivalently, FLIM imaging with conventional microscopes at frame rates accelerated by more than an order of magnitude.

Ontogenetic development of the endangered Atlantic whitefish (Coregonus huntsmaniScott, 1987) eggs, embryos, larvae, and juveniles

Atlantic whitefish ( Coregonus huntsmani Scott, 1987 ) are an endangered species endemic to Canada and are known only from Nova Scotia. Information concerning their early life-history stages — not previously described — is required to support several recovery actions under the federal Species at Risk Act (SARA). We describe the ontogenetic development of Atlantic whitefish eggs, larvae, and juveniles acquired through captive-mating of wild-caught adults, following criteria established for fishes in general and for other North American coregonine species where possible. We then conduct interspecific comparisons between Atlantic whitefish and the two most closely phylogenetically related species (i.e., lake whitefish ( Coregonus clupeaformis (Mitchill, 1818)) and cisco ( Coregonus artedii Lesueur, 1818)) to (i) identify ontogenetic differences that may facilitate field identification, (ii) determine whether differences at common ontogenetic milestones reinforce the recognition of Atlantic whitefish at the species level, and (iii) comment on whether these differences are consistent with the putative ancestral status of Atlantic whitefish. Interspecific differences were observed at all ontogenetic stages, several of which may serve as field identification criteria. Evidence for heterochrony during embryogenesis, as well as interspecific differences in egg size, myomere counts, and pigmentation patterns, substantiate the recognition of Atlantic whitefish as a valid species and support its putative ancestral status.

Effect of combination therapy on immunologic progression of human immunodeficiency virus at a population level

There is accumulating evidence from clinical trials and cohort studies that highly active antiretroviral combination therapy is effective at halting immunologic and clinical progression of human immunodeficiency virus (HIV). Its impact at a population level is less well known because the regimes may be difficult to tolerate and compliance poorer. The authors make use of population data for almost all of the HIV-infected people in Scotland in 1997 who were under clinical care and monitor their response to therapy during the first year when these effective treatments became widely available. More than two thirds of the HIV-positive patients were on some form of antiretroviral therapy during the year. The authors show that all treated groups, even those who were on changing regimes, showed net improvement in immunologic status during the year. For the group of patients on triple or quadruple therapy, there was an average increase of more than 100 CD4 cells/mm(3) over the year, with other treatment groups showing more modest, but significant, increases.

Viral subtype and heterosexual acquisition of HIV infections diagnosed in Scotland

OBJECTIVE

As at December 1998, 87% of the estimated 33 million people living with HIV throughout the world resided in Africa and South East Asia. In Scotland (and the United Kingdom), a major public health concern has been that non-B subtypes of HIV which predominate in the regions above might enter the country and spread heterosexually among the indigenous population. The authors conducted an investigation to determine if, and to what extent, such transmission had occurred.

METHODS

Stored blood samples from people who were diagnosed as HIV positive in central Scotland during 1995-7 and who were reported to have acquired their infection heterosexually, were identified. Sequence data were sought from each sample and, where obtained, viral subtype was assigned. For each case, viral subtype was linked to corresponding epidemiological details on heterosexual risk.

RESULTS

Viral sequence was obtained from specimens for 53 of 59 cases. For 43 of the 53 cases, information on region of sexual contact was known. All 19 cases who had a sexual risk in Africa or Asia had a non-B subtype (A, C, or E) while 20 of 24 cases who did not report sexual contact in these regions had a B subtype (p < 0.0001). Of the remaining 10 cases, nine had a subtype B and one a subtype C virus.

CONCLUSION

There is no evidence that non-B viral strains from developing countries have yet disseminated appreciably among indigenous heterosexual men and women within Scotland. Continuing to collect both demographic and molecular data from indigenous heterosexuals who are newly diagnosed with HIV would improve the chances of detecting rapidly any appreciable dissemination of non-B subtypes among this population if it were to occur. Such information would be helpful in informing HIV prevention strategies.

The impact of British and US guidelines for initiating combination antiretroviral therapy on estimating national treatment requirements for HIV-positive patients. Collaborating Immunologists and the Scottish HIV and AIDS Group

This paper uses comprehensive national data on HIV positive patients in Scotland to carry out a needs assessment exercise for combination antiretroviral therapy. The objective of this study was to estimate the numbers of HIV positive patients in Scotland who would be eligible for combination antiretroviral therapy under current British and US guidelines and to demonstrate the impact of these different guidelines on the resources required. The proportion of the Scottish population that would be eligible for combination therapy ranged from 76% to 91%, under different guidelines for initiating therapy. We thus estimate that for countries such as Scotland, including western Europe and the United States, where a large proportion of the HIV population became infected in the early to mid-1980s, the majority of patients will be eligible for combination therapy, regardless of the guideline.

The recent impact of antiretroviral combination therapy on CD4 counts, AIDS and death in HIV-infected persons: routine HIV surveillance in Scotland

Our aim was to investigate if the clinical benefits of combination antiretroviral therapy recently reported from clinical trials are reproduced in a population-based HIV surveillance scheme. This surveillance scheme is estimated to cover 90% of the HIV-positive population currently under immunological monitoring in Scotland. Our results showed a considerable reduction in new AIDS cases among this group from 107 in 1995 to 59 in 1996 and an estimated 58 in 1997 (allowing for reporting delay). There was a similar fall in deaths from 75 in 1995 to 59 in 1996 and an estimated 24 in 1997. These observations are temporally associated with increasing prescription of antiretroviral therapy in Scotland throughout 1996 and 1997. Examination of those individuals monitored in both 1996 and 1997 showed that from their first CD4 count in 1996 to their first count in 1997 there has been a median gain of 6 CD4 cells/mm3 (95%CI 0-12) compared with a median fall of 27 CD4 cells/mm3 (95%CI -35, -17) for those monitored in both 1995 and 1996. Highest median gains in CD4 cell counts from 1996 to 1997 were seen in those receiving triple or quadruple therapy (median gain 32CD4 cells/mm3). These results are further strengthened by the results of a separate longitudinal analysis showing a highly significant (P < 0.001) effect of treatment on CD4 cell loss with the highest mean CD4 gains being seen in those in triple or quadruple therapy. Our results indicate that the benefits of combination antiretroviral therapy previously seen in clinical trials are being reproduced at a population level. It remains to be seen if these benefits can be sustained in the long term.

Lymphocyte subpopulations in early human pregnancy

OBJECTIVE

To examine changes in lymphocyte subpopulations in early pregnancy using a methodologically appropriate study design that addresses previous sources of bias.

METHODS

Thirty-seven healthy women without risk factors for human immunodeficiency virus (HIV) were reviewed when less than 9 weeks pregnant (median 51 days, range 44-61) and again at least 4 weeks following termination of pregnancy. No woman took the oral contraceptive pill. Blood was taken on each occasion at the same time of day under the same conditions of rest and food intake, transported immediately to the laboratory, and directly prepared for analysis. Lymphocyte surface markers were determined by staining with dual-colored, isotype-matched monoclonal antibody fluorescent conjugates, followed by whole blood lysis and subsequent flow cytometric analysis.

RESULTS

Pregnancy was associated with a significant reduction in total lymphocytes (P < .0001) and also in CD4+ cells, whether expressed as a percentage of lymphocytes (P = .004), an absolute count (P = .0006), or a ratio (P = .01). Change was independent of the basal level except for lymphocytes, and almost all indices had significant correlations between pregnant and nonpregnant values.

CONCLUSIONS

In this study design, each woman served as her own control and all factors remained constant except the pregnancy state. Early pregnancy causes a reduction in total lymphocytes of about 6% expressed as a percentage of total white cell count, and in CD4+ cells by 3% as a percentage of lymphocytes, or 100/mm3. We believe this fall can be accepted as definitive.

Maternal factors in HIV transmission

In order to identify features associated with an increased risk of transmission of HIV from seropositive women to their offspring, 70 children of 58 HIV seropositive mothers were studied. Fifty-six children were followed prospectively from pregnancy; in 14 identified after the puerperium, obstetric notes were reviewed and stored serum was tested. Twelve infants of 10 mothers were HIV infected. Risk of transmission was increased in the first year after seroconversion; 5/9 infants born at this time were infected compared with 7/61 born subsequently (P < 0.001). Progression to stage IV in transmitters was more likely, occurring in the mothers of 9 infected children at a median of 3 years (range 0.5-6.5) and in mothers of 19 non-infected children at a median of 5 years (range 1-7) (P = 0.032). Maternal CD4+ counts < 400 x 10(6)/l were found in 7/12 transmitting and 7/49 non-transmitting pregnancies (P < 0.01). Differences in HIV antigenaemia did not reach significance. These factors may influence the counselling of mothers regarding their child's and their own prognosis.

Antiglycolipid antibodies, immunoglobulins and paraproteins in motor neuron disease: a population based case-control study

The role of humoral autoimmune factors in the pathogenesis of motor neuron disease (MND) is currently under considerable scrutiny. In particular, there have been many reports of abnormal serum immunoglobulin patterns and elevated titres of anti-ganglioside antibodies in patients with MND. However, many of these studies may be biased by the selection criteria for patients and controls. In order to carefully address this issue we obtained 82 blood samples from consecutive MND patients identified through a national MND register in combination with 82 community controls matched for age, sex and geographical area. We used these samples to determine the frequency of monoclonal immunoglobulins (mIgs) and measure the levels of serum immunoglobulins and anti-GM1 ganglioside antibodies in sporadic cases of MND in comparison with normal controls. Serum mIgs detected using high resolution and immunofixation agarose electrophoresis were present in 1.2% of MND patients and 2.4% of controls. Using a highly sensitive isoelectric focusing and immunoblotting method, monoclonal or oligoclonal immunoglobulins were found in 28% of MND patients and 27% of controls. Anti-GM1 antibodies were present in 26% of MND patients and 18% of controls (odds ratio = 1.5, 95%, CI 0.7-3.6) with no significant differences in titres between the 2 groups. Mean immunoglobulin G, A and M levels were equal in 2 groups. Thus, although alterations in these parameters were identified, we were unable to demonstrate any significant difference between MND patients and controls. We conclude that the majority of sporadic cases of MND are unlikely to have an autoimmune basis as judged by the lack of abnormalities in these parameters.

Use of zidovudine for drug misusers infected with human immunodeficiency virus

The use of zidovudine in drug misusers, especially current drug misusers, has not been extensively studied. Since periods of abstinence may be interspersed with drug misuse, it is necessary to establish the safety of zidovudine in injection drug misuse-related human immunodeficiency virus (HIV) infection under a variety of conditions. HIV serology became available in October 1985 and we have now examined medically 289 HIV seropositive patients, 85% of whom acquired their infection via injection drug misuse. Since March 1987 we have treated 40 individuals with zidovudine, 25 of whom were former or current injection drug misusers and one who was a heterosexual contact of a drug misuser. Eighteen patients were taking various types of opiates. Six of this latter group injected either occasionally or regularly whilst taking zidovudine. There were no adverse clinical events associated with zidovudine treatment and continued opiate drug misuse whether by mouth or by injection. Although defaults from clinic visits were a problem, these defaults were not associated with any particular form of drug misuse. Compliance with zidovudine therapy as judged by change in the mean corpuscular volume was no different for the various risk groups. In our experience it is possible to treat safely current and former drug misusers with zidovudine.

The significance of serum sperm-agglutinating antibodies in men with infertile marriages

Three hundred consecutive male partners of infertile marriages had serum samples tested for sperm agglutinating and sperm immobilising antibodies, using a micro-technique: 30.3% were found to be positive. Out of a control group of 100 fertile men 10 had antibodies detected (10%) and these at low titre; this difference was significant. The results of these serum tests were found to correlate with the results of seminal plasma tests, the mixed antiglobulin reaction for IgG and sperm cervical mucus contact testing, although all of these tests were less discriminatory with regard to fertility. The serum micro-immobilisation test showed a statistical association with fertility when analysed in those couples where both husband's and wife's tests showed no other bar to fertility.

The treatment of iron-deficiency anaemia by iron-dextran infusion, with special reference to the effect on blood-grouping, coagulation, sedimentation and haemolysis

Fifty patients with iron-deficiency anaemia were treated by total-dose infusion of iron-dextran. The therapeutic response was satisfactory in all cases. No severe systemic side effects occurred. In ten patients in whom detailed investigations were made there was no change in erythrocyte sedimentation rate or blood coagulation nor was there evidence of haemolysis following the iron-dextran infusion. No difficulty was found in ABO and Rh blood grouping and cross matching after infusion.