Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.     

Carboxylic acid replacement structure-activity relationships in suosan type sweeteners. A sweet taste antagonist. 1.

N-(4-Cyanophenyl)-N'-(2-carboxyethyl)urea (2), an analogue of suosan [1,N-(4-nitrophenyl)-N'-(2-carboxyethyl)urea], is a known high-potency sweetener derived from beta-alanine. Sulfonic and phosphonic acid analogues of 2 were prepared to develop structure-activity relationships through modification of the carboxylic acid region of this family of sweeteners. Neither of the carboxylic acid replacements resulted in sweet analogues. However, we found that N-(4-cyanophenyl)-N'-[(sodiosulfo)methyl]urea (7) is an antagonist of the sweet taste response. The bitter taste response to caffeine, quinine, and naringin was also antagonized. Antagonist 7 was found to inhibit the sweet taste perception of a variety of sweeteners. Antagonist 7 had no effect on the sour or salty taste response.     

Specific Serological Diagnosis of Leprosy with a Recombinant Mycobacterium leprae Protein Purified from a Rapidly Growing Mycobacterial Host

In this report we demonstrate the utility of an monoclonal antibody inhibition enzyme-linked immunosorbent assay based on the Mycobacterium leprae 35-kDa protein, purified from the rapidly growing host Mycobacterium smegmatis, for the serodiagnosis of multibacillary leprosy. The assay proved highly specific (97.5%) and sensitive (90%) and compared favorably with two other established methods routinely utilized for leprosy serodiagnosis.     

Role of dietary fat in calorie intake and weight gain

This paper reviews the literature on the role of dietary fat in calorie intake and body weight gain in humans and laboratory animals. An overview of 40 animal studies which compared growth on high-fat (HF) and high-carbohydrate (HC) solid/powdered diets indicated that the HF diet elicited greater weight gain in 33 out of 40 studies. Enhanced growth on the HF diet was often, but not exclusively, attributable to greater caloric intake. Additional evidence for the growth-enhancing effect of HF diets emerges from "diet option" and "supermarket" feeding studies in rats, and experimental and epidemiological studies in humans. Three principal factors that contribute to the different responses to HF and HC diets are (a) caloric density, (b) sensory properties and palatability, and (c) postabsorptive processing. It is concluded that both calorie intake and metabolic energy expenditure are biased towards weight gain when a HF diet is consumed, and that the high caloric density of high-fat diets plays a primary role in weight gain. Humans may be biologically predisposed to gain weight when a HF diet is consumed.     

The combination of plasmid interleukin-12 with a single DNA vaccine is more effective than Mycobacterium bovis (bacille Calmette-Guèrin) in protecting against systemic Mycobacterim avium infection

Sub‐unit vaccines utilizing purified mycobacterial proteins or DNA vaccines induce partial protection against mycobacterial infections. For example, immunization with DNA vaccines expressing the gene for the immunodominant 35 000 MW protein, common to Mycobacterium avium and Mycobacterium leprae but absent from the Mycobacterium tuberculosis complex, conferred significant protection against infection with either virulent M. avium or M. leprae in mice. However, the level of protection was equivalent to that obtained with the viable, attenuated vaccine, Mycobacterium bovis, bacille Calmette–Guèrin (BCG). The cytokine, interleukin (IL)‐12, is essential for priming naïve CD4⁺ T lymphocytes to differentiate into interferon‐γ (IFN‐γ)‐secreting T cells. We have used a novel self‐splicing vector expressing both chains of murine IL‐12 to determine if plasmid IL‐12 would increase the efficacy of a vaccine expressing the M. avium 35 000 MW protein (DNA‐Av35). Co‐immunization with p2AIL‐12 and DNA‐Av35 led to a significant increase in the number of antigen‐specific IFN‐γ secreting cells and total amount of IFN‐γ released, but a concomitant fall in the antibody response to the 35 000 MW protein. This pattern of response was associated with enhanced clearance of M. avium from the liver and spleen of coimmunized mice, and was significantly more effective than BCG or DNA‐Av35. alone. Following M. avium challenge there was significant increase in the expansion of the 35 000 MW antigen‐reactive T cells in the coimmunized mice. Therefore, plasmid‐delivered IL‐12 acts as an effective adjuvant to increase the protective efficacy of a single DNA vaccine against M. avium infection above that achieved by BCG, and this strategy may improve the efficacy of subunit vaccines against M. leprae and M. tuberculosis.     

Gamma interferon responses induced by a panel of recombinant and purified mycobacterial antigens in healthy,non-mycobacterium bovis BCG-vaccinated Malawian young adults

We have previously shown that young adults living in a rural area of northern Malawi showed greater gamma interferon (IFN-gamma) responses to purified protein derivatives (PPD) prepared from environmental mycobacteria than to PPD from Mycobacterium tuberculosis. In order to define the mycobacterial species to which individuals living in a rural African population have been exposed and sensitized, we tested T-cell recognition of recombinant and purified antigens from M. tuberculosis (38 kDa, MPT64, and ESAT-6), M. bovis (MPB70), M. bovis BCG (Ag85), and M. leprae (65 kDa, 35 kDa, and 18 kDa) in >600 non-M. bovis BCG-vaccinated young adults in the Karonga District of northern Malawi. IFN-gamma was measured by enzyme-linked immunosorbent assay (ELISA) in day 6 supernatants of diluted whole-blood cultures. The recombinant M. leprae 35-kDa and 18-kDa and purified native M. bovis BCG Ag85 antigens induced the highest percentages of responders, though both leprosy and bovine tuberculosis are now rare in this population. The M. tuberculosis antigens ESAT-6 and MPT64 and the M. bovis antigen MPB70 induced the lowest percentages of responders. One of the subjects subsequently developed extrapulmonary tuberculosis; this individual had a 15-mm-diameter reaction to the Mantoux test and responded to M. tuberculosis PPD, Ag85, MPT64, and ESAT-6 but not to any of the leprosy antigens. We conclude that in this rural African population, exposure to M. tuberculosis or M. bovis is much less frequent than exposure to environmental mycobacteria such as M. avium, which have antigens homologous to the M. leprae 35-kDa and 18-kDa antigens. M. tuberculosis ESAT-6 showed the strongest association with the size of the Mantoux skin test induration, suggesting that among the three M. tuberculosis antigens tested it provided the best indication of exposure to, or infection with, M. tuberculosis.     

Autocrine IL-10 impairs dendritic cell (DC)-derived immune responses to mycobacterial infection by suppressing DC trafficking to draining lymph nodes and local IL-12 production

The production of IL-12 by dendritic cells (DC) early in an immune response is considered critical for the polarization of CD4(+) T lymphocyte response towards a Th1 pattern, a key process in the clearance of intracellular pathogens. Infection of bone marrow-derived DC with Mycobacterium bovis Bacillus Calmette Guérin (BCG) induced a concurrent and dose-dependent releaseof IL-10 and IL-12. Here we examined whether the production of IL-10 by DC affected their IL-12 response to mycobacterial infection and the generation of protective immune responses in vivo. Compared to wild-type (WT) DC, DC deficient for IL-10 synthesis (IL-10(-/-)) showed increased IL-12 production in response to BCG infection and CD40 stimuli in vitro. Moreover, when transferred into mice, infected IL-10(-/-) DC were more efficient than WT DC at inducing IFN-gamma production to mycobacterial antigens in the draining lymph nodes (DLN).This effect was associated with increased trafficking of IL-10(-/-) DC to the DLN and enhanced IL-12 production by DC within the DLN. These data show that autocrine IL-10 exerts a dual inhibitory effect on the induction of primary immune responses by DC: first, by down-regulating the migration of infected DC to the DLN and second, by modulating the IL-12 production by DC in the DLN.