Specific binding of 3n-melatonin with plasma cell membrane in rats thyroid gland

The present study compared the Kato-Katz thick smear and formol ether sedimentation techniques in the diagnosis of Schistosoma mansoni infections. A stool specimen was collected from 915 individuals representing a high prevalence community (63.3%) and from 471 individuals representing a relatively low prevalence village (40%). The overall sensitivity of a single Kato-Katz smear was 70.8%, and it increased with each additional slide to reach 91.7% on examining four smears. However, the sensitivity was 83.3% when using the formol ether sedimentation technique. In terms of quantitative analysis, the geometric mean egg count was 94 eggs per gram (epg) of stool by two Kato-Katz smears, and 43 epg by the sedimentation technique. This means that more than 50% of eggs were missed when using the sedimentation technique, a fact that should be taken into consideration when relating infection level with morbidity.     

Use of 13C nuclear magnetic resonance and gas chromatography to examine methionine catabolism by lactococci

Formation of methanethiol from methionine is widely believed to play a significant role in development of cheddar cheese flavor. However, the catabolism of methionine by cheese-related microorganisms has not been well characterized. Two independent methionine catabolic pathways are believed to be present in lactococci, one initiated by a lyase and the other initiated by an aminotransferase. To differentiate between these two pathways and to determine the possible distribution between the pathways, 13C nuclear magnetic resonance (NMR) performed with uniformly enriched [13C]methionine was utilized. The catabolism of methionine by whole cells and cell extracts of five strains of Lactococcus lactis was examined. Only the aminotransferase-initiated pathway was observed. The intermediate and major end products were determined to be 4-methylthio-2-oxobutyric acid and 2-hydroxyl-4-methylthiobutyric acid, respectively. Production of methanethiol was not observed in any of the 13C NMR studies. Gas chromatography was utilized to determine if the products of methionine catabolism in the aminotransferase pathway were precursors of methanethiol. The results suggest that the direct precursor of methanethiol is 4-methylthiol-2-oxobutyric acid. These results support the conclusion that an aminotransferase initiates the catabolism of methionine to methanethiol in lactococci.     

The development of monoclonal antibodies for the therapy of cancer

Monoclonal antibodies (Mabs) were first described by K?hler and Milstein in 1975. Not only did this discovery lead to a Nobel prize, but it created an enormous scientific field that has now become a multimillion dollar industry. Mabs made the transition from laboratory reagents to clinical diagnostics very quickly. However, their development as therapeutic agents was, as predicted, more costly and time-consuming. Indeed, clinicians and scientists were required to learn a new set of rules for using these large, immunogenic, targeted agents in humans. Nevertheless, in 1997 the first Mab was licensed in the U.S. and several others will soon follow. In this review, we discuss Mab-based strategies for the treatment of cancer. We compare native, fragmented, recombinant and chimeric antibodies, bispecific antibodies, immunoconjugates, and immunoliposomes. The rationale for their development, their advantages, their in vitro and in vivo performance, and their clinical usefulness are discussed.     

Reconstruction of an abnormal hepatic vein in a donor liver: a case report

In the era of worldwide organ shortage for liver transplantation, every effort must be made to use all potentially available livers. In this case report, we present a liver graft with abnormal left hepatic vein draining directly to the right atrium of the donor heart, which was discovered during back table preparation of a liver graft. The vein was reconstructed and the subsequent liver transplantation was successful. Five years after the transplantation, no signs of complications have emerged.     

Breeding structure of screwworm fly populations (Diptera: Calliphoridae) in Colima, Mexico

Starch gel electrophoresis was used to resolve gene frequencies among populations of screwworm, Cochliomyia hominivorax (Coquerel). The loci examined coded for alpha-glycerophosphate dehydrogenase, octanol dehydrogenase, and phosphoglucomutase. Flies were sampled by traps widely distributed in Colima Province, southwestern Mexico. Gene frequencies at Odh differed significantly among the 11 populations. Alleles segregating at Pgm and alpha-Gpdh were homogeneous among populations. There were significant departures from random mating within populations, but no genetic differentiation among populations was detected. The data suggest unrestricted gene flow among populations. Departures from random mating within populations were explained by the pooling of samples from separate breeding units.     

Lack of difference in sensibility between the dominant and non-dominant hands as tested with Semmes-Weinstein monofilaments

The sensibility of the dominant hand was compared with that of the non-dominant hand using Semmes-Weinstein monofilaments in each of 22 bilateral palmar sites in 50 healthy volunteers. No difference in sensibility was found in 51% of all 2,200 tested palmar sites. Statistically significant superior sensibility was found in the non-dominant hand at 34% of all sites, whereas the dominant side showed superior sensibility in the remaining 15%.     

Comparisons using optoelectronic modulation spectroscopy of n-type GaAs epitaxial layers formed on buffer layers prepared at normal and low temperatures

Optoelectronic modulation spectroscopy (OEMS) has been used to examine defect-related states in GaAs metal-semiconductor, field-effect transistor (MESFET) structures prepared by molecular-beam epitaxy (MBE) on buffer layers formed at normal and low temperatures. The technique was used to simultaneously observe the spectra of defect states near to the interface with the buffer layer and in the active layer. There were few responses that were common to the structures. The most prominent was an electron trap with a depth of 0.92 eV. This was present throughout both structures and may be from a native defect in GaAs. With few exceptions the states seen in a particular structure were present in the active layer as well as near to the interface with the buffer layer suggesting that, in each case, the defects originated from the active/buffer layer interface or from the buffer layer. The most significant difference was that states in the low-temperature (LT)-based structure generally exhibited replicating responses with specific energy periodicities. A model describes this in terms of optical-absorption transitions to the local vibrational states of defects. Five different replica series were observed. The vibrational characteristics of the defects found in the LT material suggest that they are different in character and extent to those defects found in material formed on a normally prepared buffer layer. Their Frank-Condon energies ranged from 9–332 meV.