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G Huldt

Publications and source records attributed to G Huldt.

54 records · Page 3Linked to original sources
PubMed1974

A microplate method of enzyme-linked immunosorbent assay and its application to malaria.

A microplate method of enzyme-linked immunosorbent assay is described. This method, which may be of value in the measurement of antibodies in various infectious diseases, is simple, cheap, and easy to carry out on a large scale. For field use, results can be assessed subjectively. The potential of the test is illustrated by a small seroepidemiological study of malaria.

4-Nitrophenylphosphatase↗
PubMedDate not supplied

Visceral leishmaniasis in Somalia: prevalence of markers of infection and disease manifestations in a village in an endemic area.

Prevalence and disease manifestations of visceral leishmaniasis (VL) were studied in a Somali village in an area which has long been known to be endemic for VL. Demographic data were collected from 102 households, comprising 438 inhabitants. Clinical examination was performed of 306 individuals, 72% of the 426 eligible persons. Of these, 276 (90%) agreed to give blood and 246 (80%) to be skin tested with leishmanin. Leishmanin reactions were positive; in 26% anti-Leishmania antibodies were detected in 11%, and splenomegaly was recorded in 14% (23% of those who were seropositive). Malaria was hypoendemic and therefore unlikely to be responsible for more than 10% of the cases with splenomegaly. Three of the seropositive villagers with splenomegaly complained of feeling ill. The remaining 91 sero- and/or leishmanin-positive individuals had no complaint regarding their health and had not experienced any long period of illness. There was a slight over-representation of males in the group of sero- and/or leishmanin-positive villagers, possibly due to a gender-associated difference in exposure to the parasite. Among the patients with clinical VL treated at Mogadishu hospitals during 1989 and 1990, the male/female ratio was 3.3:1, which may indicate a selection of male patients for hospital care. Most patients were < or = 15 years old, suggesting that the highest risk of becoming clinically ill was among children.

Adolescent↗
PubMedDate not supplied

An epidemic of Plasmodium falciparum malaria in Balcad, Somalia, and its causation.

The causative factors of an epidemic of falciparum malaria were investigated in Balcad, Somalia, a town with previously low malaria transmission, where malaria incidence rose more than twenty-fold between 1986 and 1988. The emergence of chloroquine resistance, accelerated by high drug pressure, low herd immunity and favourable meteorological conditions were identified as major causes of the epidemic. Chloroquine resistance of grades RII and RIII was first observed in Balcad in 1987 and rapidly increased to 72% of the Plasmodium falciparum infections in 1988. In the absence of alternative treatment, resistance resulted in the accumulation of a massive infective reservoir and therefore increased malaria transmission, associated with intensive clinical symptomatology. The advent of chloroquine resistance was less violent in the area of Malable, where malaria is stable and communal immunity higher than in Balcad.

Adult↗
PubMedDate not supplied

Visceral leishmaniasis in Somalia: prevalence of leishmanin-positive and seropositive inhabitants in an endemic area.

In an endemic area of Somalia both humoral and cell mediated immunity against Leishmania donovani was demonstrated in 246 inhabitants. In a study of 14 patients with active visceral leishmaniasis, we found that antibodies appear early in infection and that they are then demonstrable for a limited period only. Leishmanin positivity develops later and persists longer, but does not seem to be lifelong. The majority of the immunoreactive individuals were either sero- or leishmanin positive. This finding is in accord with the result obtained in recent experimental studies indicating a regulatory effect exerted on humoral and cell mediated immunity by different T lymphocyte subsets.

Adolescent↗
PubMedDate not supplied

Diffraction imaging of single particles and biomolecules.

Theory predicts that with a very short and very intense X-ray pulse, the image of a single diffraction pattern may be recorded from a large macromolecule, a virus, or a nanocluster of proteins without the need for a crystal. A three-dimensional data set can be assembled from such images when many copies of the molecule are exposed to the beam one by one in random orientations. We outline a method for structure reconstruction from such a data set in which no independent information is available about the orientation of the images. The basic requirement for reconstruction and/or signal averaging is the ability to tell whether two noisy diffraction patterns represent the same view of the sample or two different views. With this knowledge, averaging techniques can be used to enhance the signal and extend the resolution in a redundant data set. Based on statistical properties of the diffraction pattern, we present an analytical solution to the classification problem. The solution connects the number of incident X-ray photons with the particle size and the achievable resolution. The results are surprising in that they show that classification can be done with less than one photon per pixel in the limiting resolution shell, assuming Poisson-type photon noise in the image. The results can also be used to provide criteria for improvements in other image classification procedures, e.g., those used in electron tomography or diffraction.

Electrons↗