Cloning and primary structure of the chiA gene from Aeromonas caviae

The chiA gene from Aeromonas caviae encodes an extracellular chitinase, 865 amino acids long, that shows a high degree of similarity to chitinase A of Serratia marcescens. Expression in Escherichia coli yielded an enzymatically active protein from which a leader sequence was removed, presumably during transport of the enzyme across the cell membrane.     

The effect of oxygenated mycolic acid composition on cell wall function and macrophage growth in Mycobacterium tuberculosis

There are three major structural classes of mycolic acids in the cell envelope of Mycobacterium tuberculosis (MTB): alpha-, methoxy- and ketomycolate. The two oxygen-containing classes are biosynthetically related through a common alpha-methyl hydroxymycolate intermediate. BCG strains that fail to produce methoxymycolate and instead produce only keto- and alpha-mycolic acids show apparent defects in the O-methyltransferase MMAS-3. Overproduction of MMAS-3 from MTB resulted in a complete replacement of ketomycolate by methoxymycolate in both BCG and MTB. In vitro growth of these recombinant strains lacking ketomycolate was impaired at reduced temperatures but appeared to be normal at 37 degrees C. Glucose uptake was significantly decreased in such strains, but uptake of chenodeoxycholate and glycine was unaffected. Although sensitivity to INH remained unchanged, these cells were found to be hypersensitive to ampicillin and rifampicin. Infectivity of BCG and H37Rv wild type or MMAS-3 overproducers in THP-1 cells was somewhat affected, but the ability of the strains lacking ketomycolate to grow within this macrophage-like cell line was severely compromised. In vivo labelling of mycolic acids during growth of H37Rv within THP-1 cells revealed a substantial increase in ketomycolate and alphamycolate synthesized by intracellularly grown mycobacteria. These results establish a critical role for mycolate composition in proper cell wall function during the growth of MTB in vivo.     

Biological dyes may improve the safety of local anesthetics

One of our patients was a 66-year-old woman with a T2 renal cell carcinoma weighing 3900 g. Two years after radical nephrectomy the woman was alive and well. A survey of Japanese medical literature revealed that patients with renal cell carcinomas weighing more than 2000 g have an unexpectedly favorable prognosis with a 5-year survival rate of 76.9%.     

Growth-inhibitory activities of benzofuran and chromene derivatives toward Tenebrio molitor

Growth-inhibitory activities of selected natural benzofurans (4-9), trans-cinnamic acid derivatives (10-13), chromene compounds (14 and 16), and some semisynthetic derivatives were determined in last instar larvae of Tenebrio molitor via topical administration in Me2CO. The most inhibitory of the tested compounds were 3-gamma, gamma-dimethylallyl-p-coumaric acid (10) and the benzofuran derivative 12-(p-cumaroyloxy)-tremetone (5), the former compound acting on the pupae and the latter on the last instar larvae. Several developmental deficiencies were observed, and some structure-activity relationships are discussed.     

Mapping of specific and promiscuous HLA-DR-restricted T-cell epitopes on the Plasmodium falciparum 27-kilodalton sexual stage-specific antigen

We have characterized HLA-DR-restricted T-cell epitopes on the 27-kDa protein (Pfg27), a sexual stage-specific antigen, of the human malaria parasite Plasmodium falciparum in subjects with a history of malaria. Pfg27, expressed early in the sexual stages, is recognized by monoclonal antibodies capable of reducing the infectivity of gametocytes in mosquitoes. By using 16 Pfg27-specific CD4(+)-T-cell clones derived from three donors, seven different T-cell epitopes were identified. Among them, P11 (amino acids 191 to 210 of the Pfg27 sequence, IDVVDSYIIKPIPALPVTPD) was found to contain a previously described binding motif for multiple HLA-DR allotypes. Indeed, P11 was found to be promiscuous in that it could be recognized by T cells in the context of at least five different HLA-DR molecules. The cytokine profile of the clones was mixed. Seven of nine T-cell clones exhibited a Th0-like cytokine profile, producing high levels of gamma interferon (IFN-gamma) and interleukin-4 (IL-4) upon stimulation with specific peptides and mitogens. The other two clones had a Th1-like cytokine profile with high expression of IFN-gamma and no IL-4. Identification of a promiscuous epitope in Pfg27 could play a significant role in the design of a subunit vaccine for suppressing malaria transmission.     

Kikuchi''s histiocytic necrotizing lymphadenitis associated with ruptured silicone breast implant

Mortality rates and injuries requiring medical treatment associated with sports and exercise are generally low. However, higher injury rates are reported for athletes and members of sports clubs. This study focuses on the sport- and exercise-related injury rate for various age and sex groups in the general population and how sport and exercise injury rates compare with those for other activities. The data presented are based on telephone interviews. Of the participants (N = 6,596), 335 (5.1%) reported having sustained an injury in the previous month; 46% of injuries among males and 14% of those among females were sport or exercise related. The data show a downward trend in sport- and exercise-related injury rates with increasing age. It is concluded that, as a proportion of all injuries sustained, the sport- and exercise-related injury rate is high, particularly among males. Possible future research on sport- and exercise-related injuries is discussed.     

Bcmd governs recruitment of new B cells into the stable peripheral B cell pool in the A/WySnJ mouse

BACKGROUND & AIMS: Nitric oxide is synthesized from L-arginine and is metabolized to nitrate and nitrite. This study evaluates the effects of a pharmacological blockade of NO synthesis on fluid transport by the inflamed gallbladder mucosa. METHODS: Experiments were performed in cats with cholecystitis and in control animals. NO synthase activity was measured in gallbladder tissue; the enzyme was characterized by immunoblotting techniques and localized by immunofluorescence. Fluid transport and release of nitrate and nitrite by the gallbladder mucosa and bile and bile salt secretion from the liver were registered simultaneously in vivo. RESULTS: Fluid secretion in inflamed gallbladders was reversed to a net absorption in response to the NO synthase blockers N omega-nitro-L-arginine and aminoguanidine, and formation of nitrate was reduced. The effects were reversed by L-arginine. Increased levels of inducible NO synthase in inflamed gallbladders were shown by immunoblotting, by immunofluorescence (mainly in macrophages), and by Ca(2+)-independent [3H]citrulline formation from [3H]arginine. The NO synthase blockers had no effect on gallbladder fluid transport in normal gallbladders. CONCLUSIONS: Increased levels of inducible NO synthase activity are shown in inflamed gallbladders, and a pharmacological blockade of this enzyme blocks fluid secretion and decreases nitrate release from the mucosa.