Background and Aims

Specific leaf area (SLA), a key element of the ‘worldwide leaf economics spectrum’, is the preferred ‘soft’ plant trait for assessing soil fertility. SLA is a function of leaf dry matter content (LDMC) and leaf thickness (LT). The first, LDMC, defines leaf construction costs and can be used instead of SLA. However, LT identifies shade at its lowest extreme and succulence at its highest, and is not related to soil fertility. Why then is SLA more frequently used as a predictor of soil fertility than LDMC?

Methods

SLA, LDMC and LT were measured and leaf density (LD) estimated for almost 2000 species, and the capacity of LD to predict LDMC was examined, as was the relative contribution of LDMC and LT to the expression of SLA. Subsequently, the relationships between SLA, LDMC and LT with respect to soil fertility and shade were described.

Key Results

Although LD is strongly related to LDMC, and LDMC and LT each contribute equally to the expression of SLA, the exact relationships differ between ecological groupings. LDMC predicts leaf nitrogen content and soil fertility but, because LT primarily varies with light intensity, SLA increases in response to both increased shade and increased fertility.

Conclusions

Gradients of soil fertility are frequently also gradients of biomass accumulation with reduced irradiance lower in the canopy. Therefore, SLA, which includes both fertility and shade components, may often discriminate better between communities or treatments than LDMC. However, LDMC should always be the preferred trait for assessing gradients of soil fertility uncoupled from shade. Nevertheless, because leaves multitask, individual leaf traits do not necessarily exhibit exact functional equivalence between species. In consequence, rather than using a single stand-alone predictor, multivariate analyses using several leaf traits is recommended.

Background and Aims

Genome size is a function, and the product, of cell volume. As such it is contingent on ecological circumstance. The nature of ‘this ecological circumstance’ is, however, hotly debated. Here, we investigate for angiosperms whether stomatal size may be this ‘missing link’: the primary determinant of genome size. Stomata are crucial for photosynthesis and their size affects functional efficiency.

Methods

Stomatal and leaf characteristics were measured for 1442 species from Argentina, Iran, Spain and the UK and, using PCA, some emergent ecological and taxonomic patterns identified. Subsequently, an assessment of the relationship between genome-size values obtained from the Plant DNA C-values database and measurements of stomatal size was carried out.

Key Results

Stomatal size is an ecologically important attribute. It varies with life-history (woody species < herbaceous species < vernal geophytes) and contributes to ecologically and physiologically important axes of leaf specialization. Moreover, it is positively correlated with genome size across a wide range of major taxa.

Conclusions

Stomatal size predicts genome size within angiosperms. Correlation is not, however, proof of causality and here our interpretation is hampered by unexpected deficiencies in the scientific literature. Firstly, there are discrepancies between our own observations and established ideas about the ecological significance of stomatal size; very large stomata, theoretically facilitating photosynthesis in deep shade, were, in this study (and in other studies), primarily associated with vernal geophytes of unshaded habitats. Secondly, the lower size limit at which stomata can function efficiently, and the ecological circumstances under which these minute stomata might occur, have not been satisfactorally resolved. Thus, our hypothesis, that the optimization of stomatal size for functional efficiency is a major ecological determinant of genome size, remains unproven.

Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and temporal parameters of movement. Research on motor learning suggests that augmented feedback may provide a beneficial effect for training movement. This study examined the effects of the presence and frequency of online augmented visual kinematic feedback (AVKF) and clinician-provided perceptual feedback on speech accuracy in 2 adults with acquired AOS. Within a single-subject multiple-baseline design, AVKF was provided using electromagnetic midsagittal articulography (EMA) in 2 feedback conditions (50 or 100%). Articulator placement was specified for speech motor targets (SMTs). Treated and baselined SMTs were in the initial or final position of single-syllable words, in varying consonant-vowel or vowel-consonant contexts. SMTs were selected based on each participant's pre-assessed erred productions. Productions were digitally recorded and online perceptual judgments of accuracy (including segment and intersegment distortions) were made. Inter- and intra-judge reliability for perceptual accuracy was high. Results measured by visual inspection and effect size revealed positive acquisition and generalization effects for both participants. Generalization occurred across vowel contexts and to untreated probes. Results of the frequency manipulation were confounded by presentation order. Maintenance of learned and generalized effects were demonstrated for 1 participant. These data provide support for the role of augmented feedback in treating speech movements that result in perceptually accurate speech production. Future investigations will explore the independent contributions of each feedback type (i.e. kinematic and perceptual) in producing efficient and effective training of SMTs in persons with AOS.

Functional adipocyte glucose disposal is a key component of global glucose homeostasis. PKCβII is involved in rat skeletal muscle cell ISGT. Western blot analysis and Real-Time PCR revealed 3T3-L1 cells developmentally regulated PKCβ splicing such that PKCβI was downregulated and PKCβII was upregulated during the course of differentiation. An initial glucose uptake screen using PKC inhibitor LY379196 pointed to a PKC isozyme other than PKCζ mediating 3T3-L1 adipocyte ISGT. Subsequent use of PKCβII inhibitor CGP53353 pointed to a role for PKCβII in ISGT. Western blot analysis showed that CGP53353 specifically inhibited phosphorylation of PKCβII Serine 660. Subcellular fractionation and immunofluorescence demonstrated that PKCβII regulates GLUT4 translocation. Further western blot, immunofluorescence and co-immunoprecipitation analysis reveal that PKCβII inhibition does not affect mTORC2 activity yet abrogates phosphorylation of Akt Serine 473. PKCβII regulates GLUT4 translocation by regulating Akt phosphorylation and thus activity.

An integrated and coordinated set of programs has been established to meet ICBG goals in Papua New Guinea (PNG). Here we give an overview of the PNG ICBG and focus on the key elements and major steps taken to establish a program necessary for the pharmacological assessment of botanicals and traditional medicines in PNG and, by extrapolation, in other developing countries.

BACKGROUND—Insulin resistance is associated with ischaemic heart disease and has been proposed as a risk factor for subsequent myocardial infarction.
AIM—To investigate the potential use of a recently proposed insulin resistance index in identifying insulin resistance in patients admitted with an acute coronary syndrome.
METHODS—Single centre study of 441 non-diabetic patients admitted with chest pain to a coronary care unit and followed prospectively for a median of three years for outcome. Admission glucose and insulin concentrations were measured and from these values an admission index of insulin resistance (AIRI) calculated. Its association with other known factors in the insulin resistance syndrome, and subsequent outcome, was examined.
RESULTS—The AIRI was greater in patients with myocardial infarction than in a control group without myocardial infarction (p < 0.0001). A Cox regression model for subsequent cardiac death identified previous myocardial infarction (p < 0.0001), infarct size (p < 0.0001), and AIRI (p = 0.0033) as positive risk predictors. Patients of Indian subcontinent ethnic origin had greater AIRI values than white patients: mean (SD) 7.5 (1.3) v 4.6 (0.2), p < 0.001.
CONCLUSIONS—A simple index of insulin resistance measured on patients admitted with myocardial infarction provides an important predictive measure of poor outcome and is superior to admission glucose measurement. It may be useful in identifying patients admitted with myocardial infarction who could benefit from alternative early management strategies.


Keywords: myocardial infarction; unstable angina; insulin resistance; glucose

Background—Basic fibroblast growth factor (bFGF) promotes angiogenesis and healing of gastric ulcers in rats, and bFGF expression is up regulated in such ulcers. However, little is known about expression of bFGF in human gastric mucosa. 
Aims—To investigate bFGF expression in intact human gastric mucosa and gastric ulcers and to determine whether low bFGF content or altered binding by mucosa is associated with ulceration. 
Subjects—Endoscopy outpatients, gastrectomy patients, and organ donors. 
Methods—bFGF was isolated by heparin affinity chromatography and characterised by western blotting and endothelial cell bioassay. bFGF was measured by immunoassay and its distribution defined by immunohistochemistry and in situ hybridisation. Binding of bFGF by heparan sulphate proteoglycans was investigated by sodium chloride and heparin extraction. 
Results—Bioactive bFGF (19 kDa) was detected in normal mucosa but bFGF mRNA was not found. bFGF expression was up regulated in granulation tissue endothelial cells, mononuclear cells, and epithelial cells at the ulcer rim. Gastric ulcer patients had constitutively low bFGF concentrations in intact antral mucosa which were not explained by changes in binding to heparan sulphate proteoglycans. 
Conclusions—bFGF expression is up regulated in human gastric ulcers. Low intact mucosal bFGF content is associated with gastric ulceration. 



Keywords: basic fibroblast growth factor; gastric mucosa; heparan sulphate proteoglycan; peptic ulceration

In this study, we report on the distribution of tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) mRNA expression in human normal colorectal mucosa, adenomas and adenocarcinomas. Northern blot analysis showed five TIMP-3 mRNA transcripts to be present in normal mucosal epithelium and in moderately and poorly differentiated carcinoma. Adenomas and well-differentiated carcinomas were not examined in this part of the investigation. In situ hybridization studies showed no detectable TIMP-3 mRNA in normal and adenomatous tissue. In contrast, TIMP-3 mRNA is localized to stromal fibroblast-like cells in colorectal carcinomas, with an increased incidence in moderately and poorly differentiated groups compared with well-differentiated carcinomas. Expression in both the moderately and the poorly differentiated tumour groups was strongest at the tumour invasive edge; none of the poorly differentiated carcinomas showed mRNA expression in regions ahead of the invasive edge, compared with 3 of 12 of the moderate group. To our knowledge, this is the first detailed report on the regional localization of TIMP-3 mRNA in colorectal tumours. We suggest that the lack of TIMP-3 mRNA expression in host stromal tissues ahead of poorly differentiated carcinomas may contribute to their increased invasiveness.

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Objective: The purpose of this study was to prospectively test the null hypothesis that there is no difference in the clinical effectiveness of azithromycin and erythromycin for the treatment of chlamydia cervicitis in pregnancy.

Methods: All antepartum obstetrical patients underwent routine screening for chlamydia cervicitis using a DNA probe assay (Gen-Probe Pace, San Diego, CA). Women who tested positive for chlamydia cervicitis were prospectively randomized to receive either azithromycin 1 g orally at enrollment, or erythromycin 500 mg orally 4 times a day for 7 days. Sexual partners were referred to the county health department for evaluation and treatment. A test of cure was repeated in 2 weeks. Results were analyzed by chi-square analysis and Fisher's exact test when indicated.

Results: One hundred forty women tested positive for chlamydia cervicitis and agreed to randomization. There were 4 (6.2%) treatment failures in the azithromycin group and 18 (27.7%) in the erythromycin group (P = 0.005). Gastrointestinal side effects were reported by 42 (65.5%) of the women taking erythromycin, but only 12 (19.4%) of those taking azithromycin (P < 0.002). Gastrointestinal side effects and resultant noncompliance were significantly related to treatment failure with erythromycin.

Conclusions: The findings of this study support the conclusion that a single dose of azithromycin is a significantly more effective and better tolerated treatment regimen for chlamydia cervicitis in pregnancy than erythromycin which is currently recommended.

The oestrogen receptor content of colorectal adenocarcinoma was investigated using an established ligand binding biochemical assay and two more recently introduced techniques using specific monoclonal antibodies (Abbott ER-EIA and ER-ICA assay kits). Twenty nine tumours were investigated by the ligand binding assay. Only one (3.4%) tumour gave a weakly positive result (11 fmol/mg cytosol protein); the rest were all negative. Where sufficient tissue was available, the receptors were also determined by a quantitative immunoassay in 18 patients and an immunohistochemical method in 13 patients. The results were similarly all negative. It is concluded that most colorectal carcinomas, irrespective of sex, are oestrogen receptor negative, and it is thus unlikely that hormonal manipulation would have an influence on the course of the disease.

3'-Azido-2',3'-deoxythymidine and carbovir [racemic and (-) enantiomer] were evaluated individually and in combination for antiviral activity against human immunodeficiency virus type 1 replication and cytotoxicity in vitro. The combination of these drugs synergistically inhibited human immunodeficiency virus type 1 replication in C3 and Jurkat cells and in human peripheral blood mononuclear cells, although the same combination also produced synergistic cytotoxicity in human peripheral blood mononuclear cells.

We evaluated several simple laboratory tests that have been used to identify pathogenic serotypes of Yersinia enterocolitica or to indicate the pathogenic potential of individual strains. A total of 100 strains of Y. enterocolitica were studied, including 25 isolated during five outbreak investigations, 63 from sporadic cases, and 12 from stock cultures. The pyrazinamidase test, which does not depend on the Yersinia virulence plasmid, correctly identified 60 of 63 (95% sensitivity) strains of pathogenic serotypes and 34 of 37 (92% specificity) strains of nonpathogenic serotypes. Salicin fermentation-esculin hydrolysis (25 degrees C, 48 h) correctly identified all 63 (100% sensitivity) strains of the pathogenic serotypes and 34 of 37 (92% specificity) strains of the nonpathogenic serotypes. The results of the pyrazinamidase and salicin-esculin tests disagreed for only 7 of the 100 strains of Y. enterocolitica, and these would require additional testing. Congo red-magnesium oxalate (CR-MOX) agar determines Congo red dye uptake and calcium-dependent growth at 36 degrees C, and small red colonies are present only if the strain contains the Yersinia virulence plasmid. This test has proven to be extremely useful for freshly isolated cultures, but only 15 of 62 strains of pathogenic serotypes that had been stored for 1 to 10 years were CR-MOX positive. None of the 16 strains of Y. enterocolitica serotype O3 fermented D-xylose, so this test easily differentiated strains of this serotype, which now appears to be the most common in the United States. Although antisera that can actually be used to serotype strains of Y. enterocolitica are not readily available, the four simple tests described above can be used to screen for pathogenic serotypes.

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Two collections of trimethoprim R plasmids, isolated from strains of Escherichia coli during 1978-83 and 1987-8 respectively, were retrospectively screened with specific biotinylated DNA probes for the presence of genes encoding particular DHFR enzymes. The results confirmed that the type I DHFR gene was the predominant plasmid-encoded gene conferring trimethoprim resistance in strains of E. coli from the Nottingham area of the UK, but indicated that genes encoding the more recently recognized types of DHFR enzymes had appeared in the bacterial gene pool and could be recognized with increased frequency in the latter plasmid collection. This was particularly true of the type IIIa and type VII enzymes which together accounted for 27% of the trimethoprim R plasmids examined in 1987-8.

From 1 December 1988 through 28 February 1991, 7,290 rectal swab specimens received in our laboratory were screened for Yersinia enterocolitica. A total of 76 patients had Y. enterocolitica isolated from their stool samples. Of these patients, 59 (77.6%) were 12 months old or younger. Y. enterocolitica was second only to Salmonella spp. in this age group. Routine screening for Y. enterocolitica may be warranted in hospitals serving large pediatric populations.

The CD4 molecule, a glycoprotein expressed primarily on the cell surface of specific T lymphocytes, is thought to function in T-cell antigen recognition and activation. In addition, CD4 serves as a receptor for human immunodeficiency virus type 1 (HIV-1) by a direct interaction with the HIV-1 surface glycoprotein (gp120). To further characterize the HIV-1-cell interaction, a HeLa cell line was established that expressed a chimeric molecule of CD4 and decay-accelerating factor (DAF). In the chimeric CD4-DAF molecule the transmembrane and cytoplasmic domains of CD4 were deleted and replaced with the carboxy-terminal 37 amino acids of DAF. This resulted in the anchoring of the extracellular domain of CD4 to the cell membrane via a glycophospholipid linkage. The glycophospholipid-anchored CD4 had a molecular size of approximately 56 to 62 kDa and was released following treatment of the cells with phosphatidylinositol-specific phospholipase C. HeLa cells expressing the CD4-DAF hybrid could be infected with HIV-1, as evidenced by reverse transcriptase activity, p24 core antigen content, and infectious virus production. In addition, transfection of the HeLa CD4-DAF cells with a plasmid that directs the synthesis of HIV-1 envelope glycoproteins or cocultivation with HeLa cells expressing the virus glycoproteins resulted in syncytium formation. These results indicate that the transmembrane and cytoplasmic domains of the CD4 molecule are dispensable for both HIV infection and syncytium formation.

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(-)-Carbovir, the minus optical isomer of carbocyclic-2',3'-didehydro-2',3'-dideoxyguanosine, has been shown to be the biologically active form for the inhibition of human immunodeficiency virus type 1 replication. The concentration of (-)-carbovir required to reduce reverse transcriptase activity by 50% compared with the control was 0.8 microM in H9 cells infected with the HTLV-IIIb strain; the 50% inhibitory concentration for cytotoxicity was greater than 2 mM in these cells. The effect of the timing of drug addition, pre- and postinfection, and the effect of increasing amounts of virus on the antiviral activities of (-)-carbovir and 3'-azido-3'-deoxythymidine were determined.

We have generated two serum- and anchorage-dependent revertants from NIH 3T3 cells transformed with multiple copies of the human c-H-ras oncogene. In both revertants, the c-H-ras oncogene was fully expressed. Fusion of either revertant with untransformed cells or of the two revertants with one another resulted in transformed progeny. These results indicated that the two revertants were recessive and in different complementation groups. We believe that in our two revertants some of the genes mediating the transforming activity of the c-H-ras oncogene are defective; we are attempting to identify these mediator genes.

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An unusual isolate from a human leg wound was identified as Xenorhabdus luminescens. This finding led to the discovery or isolation of four additional strains, two from blood and two from wounds. Three of the five strains were from patients in San Antonio, Tex. Three strains were studied by DNA-DNA hybridization (S1 nuclease-trichloroacetic acid method) and were 77 to 100% related to each other, 34% related to the type strain of X. luminescens, 35 to 40% related to three of Grimont's other DNA hybridization groups of X. luminescens, and 9% related to the type strain of Xenorhabdus nematophilus. The new group of five strains was designated X. luminescens DNA hybridization group 5. All five strains were very inactive biochemically and fermented only D-glucose and D-mannose. The key reactions for recognizing this new organism are yellow pigment production, negative test for nitrate reduction to nitrite, weak bioluminescence (10 to 15 min of dark adaptation is required to see the weak light produced), and a unique hemolytic reaction on sheep blood agar plates incubated at 25 degrees C. Two case histories of strains from wounds are given; these suggest that X. luminescens DNA hybridization group 5 may be a new bacterial agent that causes wound infections. The two cases of wound infection, along with the two blood isolates, suggest that the new organism is clinically significant.

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Three strains of a Pasteurella haemolytica-like bacterium were isolated from lesions of a progressive granuloma of cattle in southern Brazil. Their characteristics and their differentiation from P. haemolytica varieties and Actinobacillus lignieresii are described. The name "Pasteurella granulomatis" is proposed for this apparently new taxon.

Sera from 91 patients with hereditary angioedema were screened for thyroid antibodies. The results for the 77 patients more than 17 years old were compared with previously published data for the prevalence of thyroid disease in a large community (Whickham). Of the female patients with hereditary angioedema, the prevalence of thyroglobulin antibodies (TGA) was 14.0%, higher than the expected 3% (p less than 0.001). The prevalence of thyroid microsomal antibodies (TMA) was 20%, also higher than the expected 7.6% (p less than 0.01). The age distributions of the females in both groups differed: in the group with hereditary angioedema there was a greater proportion of younger patients which should have resulted in a lower prevalence of thyroid antibodies. Adjusting for related patients with hereditary angioedema, there was still an increased prevalence of TGA (p less than 0.01) and TMA (p less than 0.01).