Thermal Analysis Studies of Glass Dispersion Systems

Glass dispersion systems were examined using differential scanning calorimetry. The addition of a crystalline additive to a glassy vehicle resulted in a reduction of the vehicle's glass transition temperature. Mixtures of glassy materials were immiscible, partially miscible, or completely miscible. The results can be explained using the concept of miscibility among liquids. By combining two miscible glasses in the proper ratio, it was possible to obtain greater physical stability than with either of its glassy components. This was demonstrated with a 1:1 mixture of citric acid and acetaminophen which showed no changes in its thermogram after seven weeks of storage at 23°C. The glass transition of this mixture is about 18° C.     

Unequal subfamily proportions among honey bee queen and worker brood

Queens from three colonies of feral honey bees, Apis mellifera were removed and placed in separate nucleus colonies. For each colony, eggs and larvae were taken from the nucleus and placed in the main hive on each of 3-4 consecutive weeks. Workers in the queenless parts selected young larvae to rear as queens. Queen pupae, together with the surrounding worker pupae, were removed from each colony and analysed at two to three microsatellite loci to determine their paternity. In all three colonies, the paternity of larvae chosen by the bees to rear as queens was not a random sample of the paternities in the worker brood, with certain subfamilies being over-represented in queens. These results support an important prediction of kin selection theory: when colonies are queenless, unequal relatedness within colonies could lead to the evolution of reproductive competition, that is some subfamilies achieving greater reproductive success than others. The mechanism by which such dominance is achieved could be through a system of kin recognition and nepotism, but we conclude that genetically based differential attractiveness of larvae for rearing as queens is more likely.Copyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour.     

Sequence analysis of Tn10 insertion sites in a collection of Escherichia coli strains used for genetic mapping and strain construction

The chromosomal insertion sites of Tn10-containing Escherichia coli strains were amplified by inverse PCR, and the nucleotide sequences of the junctions were determined. In 95 strains analyzed, 88 unique Tn10 positions were determined and matched to the E. coli chromosome sequence. Two gaps in insertion site positions were noted, one including the terminus of DNA replication and another bounded by recombination hot spots RhsA and RhsB.     

Regulation of insulin-stimulated GLUT4 translocation by Munc18c in 3T3L1 adipocytes

Insulin stimulates glucose transporter (GLUT) 4 vesicle translocation from intracellular storage sites to the plasma membrane in 3T3L1 adipocytes through a VAMP2- and syntaxin 4-dependent mechanism. We have observed that Munc18c, a mammalian homolog of the yeast syntaxin-binding protein n-Sec1p, competed for the binding of VAMP2 to syntaxin 4. Consistent with an inhibitory function for Munc18c, expression of Munc18c, but not the related Munc18b isoform, prevented the insulin stimulation of GLUT4 and IRAP/vp165 translocation to the plasma membrane without any significant effect on GLUT1 trafficking. As expected, overexpressed Munc18c was found to co-immunoprecipitate with syntaxin 4 in the basal state. However, these complexes were found to dissociate upon insulin stimulation. Furthermore, endogenous Munc18c was predominantly localized to the plasma membrane and its distribution was not altered by insulin stimulation. Although expression of enhanced green fluorescent protein-Munc18c primarily resulted in a dispersed cytosolic distribution, co-expression with syntaxin 4 resulted in increased localization to the plasma membrane. Together, these data suggest that Munc18c inhibits the docking/fusion of GLUT4-containing vesicles by blocking the binding of VAMP2 to syntaxin 4. Insulin relieves this inhibition by inducing the dissociation of Munc18c from syntaxin 4 and by sequestering Munc18c to an alternative plasma membrane binding site.     

Epididymal compounds and antioxidants in diluents for the frozen storage of ram spermatozoa

The epididymal compounds taurine, hypotaurine and inositol, and the antioxidants carnosine and ascorbic acid, were added to Tris-based diluents containing varying concentrations of glycerol, and their effect on the post-thaw motility characteristics and fertility of ram spermatozoa was examined. Overall, the post-thaw motility characteristics of spermatozoa were better when semen was frozen in the presence rather than in the absence of glycerol. Only taurine protected spermatozoa during cryopreservation; the presence of 25 mM or 50 mM taurine significantly improved the post-thaw percentage of motile spermatozoa but this had no effect on fertility after cervical or laparoscopic insemination of ewes. Increasing the concentration of taurine to more than 100 mM significantly reduced the percentage of motile spermatozoa, compared with the lower concentrations of the amino acid. The presence of more than 50 mM carnosine or ascorbic acid significantly reduced all motility characteristics compared with the control diluent. Given that hypotaurine, carnosine, or ascorbic acid did not improve post-thaw motility, the cryoprotective effect of taurine may be attributable to its osmoregulation rather than to its antioxidant properties.     

Effects of self-care education on the health status of inner-city patients with osteoarthritis of the knee

OBJECTIVE: To evaluate a concise program of self-care education delivered by an arthritis nurse specialist as an adjunct to primary care for inner-city patients with knee osteoarthritis (OA). METHODS: An attention-controlled clinical trial; 211 inner-city patients with knee OA were assigned arbitrarily to education (E) or attention-control (AC) conditions. Group E received an individualized 30-60-minute educational intervention that emphasized nonpharmacologic management of joint pain, preservation of function by problem-solving, and practice of principles of joint protection. Brief telephone contacts 1 week and 4 weeks later monitored and reinforced new self-care activities. Group AC viewed a 20-minute standardized public education presentation on arthritis and received followup telephone calls (only to encourage continued participation in the study). Outcomes included the Health Assessment Questionnaire (HAQ) Disability and Discomfort Scales, 10-cm visual analog scales measuring knee pain at rest and while walking, and the Quality of Well-Being (QWB) scale. Assessments were made at baseline and at 4-month intervals for 1 year. RESULTS: A total of 165 subjects (78%) completed all assessments. After control for baseline status, group E had significantly lower scores for disability and resting knee pain throughout the year of postintervention followup (P < 0.05 for both). Effects were somewhat discordant. By 12 months, functional benefits had begun to wane, while the effect on resting knee pain had grown. The overall effects of education on walking knee pain, overall joint pain (by HAQ), and general health status (by QWB) were not significant. CONCLUSION: Self-care education for inner-city patients with knee OA, delivered as an adjunct to primary care, was found to result in notable preservation of function and control of resting knee pain. The magnitude of the observed effects compares well with those of more labor-intensive and time-consuming intervention models. However, more sustained preservation of function and consistent effects on pain may require prolonged, more proactive followup, either by the patient educator or by a trained clinical assistant dedicated to the task of supporting self-care by patients with knee OA.     

Adult heart transplantation under tacrolimus (FK506) immunosuppression: histopathologic observations and comparison to a cyclosporine-based regimen with lympholytic (ATG) induction

BACKGROUND: Tacrolimus (FK506) is an effective immunosuppressant for human heart transplantation, but information about its effects on cardiac allograft and nonallograft kidney and liver histopathologic study is limited. METHODS: We therefore reviewed 1145 endomyocardial biopsy specimens and eight autopsy results from 80 heart transplant recipients who received tacrolimus as baseline immunosuppression. These were compared with 619 endomyocardial biopsy specimens and four autopsy results from 51 patients treated with cyclosporine-based immunosuppression with lympholytic induction (CLI) by use of rabbit anti-thymocyte globulin. Twenty-one histologic features including the International Society for Heart and Lung Transplantation histopathologic grade were retrospectively assessed without knowledge of the treatment regimen. The lymphocyte growth index on biopsy specimens obtained from these patients was also compared. RESULTS: In general, there were no qualitative differences in the histopathologic appearance of various allograft syndromes between tacrolimus- and CLI-treated patients. Thus histopathologic criteria used to diagnose various graft syndromes are applicable under tacrolimus immunosuppression. However, early (between 10 and 30 days) after transplantation, biopsy specimens from patients treated with tacrolimus showed a significantly higher percentage of inflamed fragments (p = 0.02), the inflammation tended to be more severe (p = 0.09), and the rejection grade tended to be slightly higher (p = 0.08). In contrast, during the late transplantation period (275 to 548 days), biopsy specimens from patients treated with CLI showed a significantly higher percentage of inflamed fragments (p = 0.03), more severe inflammation (p = 0.03), higher rejection grades (p = 0.01), and a higher frequency of Quilty lesions (p = 0.05). Although overall freedom from any grade 3A or higher rejection was greater in the CLI-treated arm, tacrolimus was successfully used to treat refractory rejection in three patients from the CLI-treated arm. Concern has been raised in the literature about the possibility of tacrolimus being a direct hepatotoxin and an accelerant of allograft obliterative arteriopathy. However, no evidence to support either of these contentions was detected in this patient population. In contrast, tacrolimus is clearly nephrotoxic, although similar to cyclosporine in this regard. CONCLUSIONS: Tacrolimus is an effective immunosuppressive drug for heart transplantation. The cardiac allograft histopathologic study of patients treated with tacrolimus immunosuppression does not significantly differ from those given conventional, cyclosporine-based triple therapy with lympholytic induction.