Increased gelatinase activity in systemic sclerosis dermal fibroblast cultures with unaltered gelatinase A mRNA expression

Gelatinase A is one of the matrix metalloproteinases, the principle enzymes degrading extracellular matrix (ECM) and basement membrane components. The aim of this study was to study gelatinase expression in systemic sclerosis (SSc). Fibroblasts were grown from uninvolved and involved skin of SSc patients and from healthy controls. Gelatinase activity was assayed by degradation of tritium-labeled gelatin. Gelatinase A mRNA was quantitated by competitive reverse transcriptase-polymerase chain reaction (RT-PCR). Gelatinase activity was significantly increased in both uninvolved and involved SSc cultures. However, gelatinase A mRNA was unaltered in both cases. Neither SSc nor control skin fibroblasts expressed gelatinase B, indicating that the increased gelatinase activity is not due to gelatinase B induction. Gelatinase A is a specific basement membrane degrading enzyme, so increased gelatinase activity may be related to the pathophysiology of SSc by initiating microvascular damage and leakage of substances capable of producing further endothelial cell damage or fibroblast activation. Increased gelatinase activity in SSc fibroblasts seems to be regulated at translational and/or post-translational level.

Jelly belly: a Drosophila LDL receptor repeat-containing signal required for mesoderm migration and differentiation

Inductive interactions subdivide the Drosophila mesoderm into visceral, somatic, and heart muscle precursors. The muscle precursors form organs by executing tissue-specific migrations and cell fusions. We identified a novel gene, jelly belly (jeb), which is required for visceral mesoderm development. jeb encodes a secreted protein that contains an LDL receptor repeat. In jeb mutants, visceral mesoderm precursors form, but they fail to migrate or differentiate normally; no visceral muscles develop. Jeb protein is produced in somatic muscle precursors and taken up by visceral muscle precursors. jeb reveals a signaling process in which somatic muscle precursors support the proper migration and differentiation of visceral muscle cells. Later in embryogenesis, jeb is transcribed in neurons and Jeb protein is found in axons.

Enhancing the specificity of the COBAS AMPLICOR CT/NG test for Neisseria gonorrhoeae by retesting specimens with equivocal results

The COBAS AMPLICOR CT/NG test for Neisseria gonorrhoeae cross-reacts with certain strains of nonpathogenic Neisseria species. In some strains, the target sequence is identical to that of N. gonorrhoeae, whereas other strains have a small number of mismatches within the regions recognized by the primers or probe used in the COBAS AMPLICOR NG test. These cross-reactive strains are occasionally present in urogenital specimens, causing false-positive results in the COBAS AMPLICOR NG test. Analysis of the data generated in a large multicenter clinical trial showed that 2.9% of the specimens gave signals between A(660)s of 0.2 and 3.5 but that one-half of these equivocal specimens did not contain N. gonorrhoeae. Most of these equivocal specimens were correctly classified as true positive or true negative by retesting in duplicate and defining a PCR-positive result as two of three results with an A(660) of > or =2.0. If specimens had been classified as positive or negative based on a single test result using a cutoff of an A(660) of 0.2, specificity would have ranged from 96.2 to 98.9% depending on specimen type, sex, and presence of symptoms. By employing the equivocal zone-retesting algorithm, specificity increased to 98.6 to 99.9% with little effect (0.1 to 4.9% decrease) on sensitivity in most specimen types, enabling the test to achieve a positive predictive value of at least 90% in populations with a prevalence of 4% or higher. In lower-prevalence populations, the test could be used to screen for presumptive infections that would have to be confirmed by an independent test.

Association of Mycoplasma genitalium with nongonococcal urethritis in heterosexual men

Chlamydia trachomatis and Neisseria gonorrhoeae are universally acknowledged as urethral pathogens, yet the etiology in the majority of cases of urethritis is unclear. Our case-control study assessed the association of Mycoplasma genitalium, Ureaplasma urealyticum, and other potential pathogens with acute nongonococcal urethritis (NGU) in heterosexual men presenting to an urban sexually transmitted diseases clinic. M. genitalium was detected in 27 (22%) of 121 NGU case patients and in 5 (4%) of 117 control subjects (P<.01). Although C. trachomatis was detected in 36 (30%) of 121 NGU case patients and in 4 (3%) of 117 control subjects (P<.01), only 3 men with NGU were infected with both C. trachomatis and M. genitalium. U. urealyticum was not associated with NGU. By multivariate analyses, controlling for age, race, history of prior urethritis, and chlamydial infection, M. genitalium was associated with a 6.5-fold increased risk of urethritis (95% confidence interval, 2.1-19.5), which supports a role of this organism in the etiology of NGU.

Human immunodeficiency virus infection and genital ulcer disease in South Africa: the herpetic connection

BACKGROUND AND OBJECTIVES

While genital ulcers are a risk factor in HIV infection, the association of specific agents of genital ulcer disease (GUD) with HIV infection may vary.

GOAL

To determine the etiology of GUD in HIV-infected and HIV-uninfected men attending sexually transmitted disease (STD) clinics in Durban, Johannesburg, and Cape Town, South Africa, and the association of previous and current sexually transmitted infections with HIV infection in men with ulcerative and nonulcerative STDs.

STUDY DESIGN

A cross-sectional study of 558 men with genital ulcers and 602 men with urethritis.

RESULTS

Patients with GUD were more likely to be infected with HIV than patients with urethritis (39.4% versus 21.4%, P< or =0.001). Herpes simplex virus 2 (HSV-2) was the most common agent identified in ulcer specimens (35.9%), and was detected in a significantly higher proportion of ulcer specimens from HIV-infected patients than in specimens from HIV-uninfected patients (47.4% versus 28.2%, P< or =0.001). Patients infected with HIV-1 were significantly more likely to have HSV-2 infection, as measured by the presence of the antibody to glycoprotein G-2, than patients not infected with HIV (63.1% versus 38.5%, P< or =0.001). Patients infected with HIV-1 were also significantly more likely to have initial HSV-2 infection than HIV-uninfected patients with GUD (50.0% versus 31.6%, P = 0.007). Haemophilus ducreyi was detected in 31.7% of ulcer specimens; prevalence did not vary by HIV-infection status. Treponema pallidum DNA was detected significantly less frequently in ulcer specimens from patients infected with HIV than in specimens from patients not infected with HIV (10.2% versus 26%, P< or =0.001); no association was found between HIV-infection status and fluorescent treponemal antibody absorption test seroreactivity, even when men with M-PCR-positive syphilis lesions were excluded from the analyses.

CONCLUSION

The authors found that HSV-2 is a more common etiology of GUD than has been suggested by previous studies conducted in South Africa; serologic evidence of HSV-2 infection and current cases of genital herpes are strongly associated with HIV infection among men who present to STD clinics with GUD or urethritis.

Levels of endothelial cell stimulating angiogenesis factor and vascular endothelial growth factor are elevated in psoriasis

Neovascularization appears to play an early and important part in the evolution of psoriatic plaques. We studied the distribution and production of two known angiogenesis factors, endothelial cell stimulating angiogenesis factor (ESAF) and vascular endothelial growth factor (VEGF), in the skin of patients with chronic plaque psoriasis and normal control subjects. Our results showed that tissue levels of ESAF and VEGF were significantly elevated in involved as compared with normal control skin (P = 0.006 and P < 0. 0001, respectively). Tissue levels of ESAF and VEGF were also raised in involved skin as compared with uninvolved skin in patients with psoriasis (P = 0.001 and P < 0.0001, respectively). Tissue levels of ESAF and VEGF in plaques of psoriasis correlated closely with the clinical severity of psoriasis (r = 0.6 and r = 0.9, respectively). Serum levels of ESAF and VEGF were significantly raised in patients with psoriasis as compared with control subjects (P = 0.001 and P = 0.02, respectively). In vitro culture studies revealed that ESAF is produced by both keratinocytes and fibroblasts in approximately equal quantities in normal skin, whereas VEGF is secreted predominately by keratinocytes. A similar pattern is seen in both involved and uninvolved skin of patients with psoriasis. However, there is increased secretion of both factors in keratinocytes and fibroblasts from involved and uninvolved skin as compared with normal control skin (P < 0.001). The increased levels and secretion in plaques of psoriasis of two molecules, ESAF and VEGF, known to promote new blood vessel formation, suggest a pathogenetic role for them in this disease.

Chancroid, primary syphilis, genital herpes, and lymphogranuloma venereum in Antananarivo, Madagascar

Ulcer material from consecutive patients attending clinics in Antananarivo, Madagascar, was tested using multiplex polymerase chain reaction (M-PCR) to detect Treponema pallidum, Haemophilus ducreyi, and herpes simplex virus. Sera were tested for syphilis and for IgG and IgM antibodies to Chlamydia trachomatis by microimmunofluorescence testing (MIF). By M-PCR, 33% of 196 patients had chancroid, 29% had syphilitic ulcers, and 10% had genital herpes; 32% of the ulcer specimens were M-PCR negative. Compared with M-PCR, syphilis serology was 72% sensitive and 83% specific. The sensitivity of clinical diagnosis of syphilis, chancroid, and genital herpes was 93%, 53%, and 0% and specificity was 20%, 52%, and 99%, respectively. Less schooling was associated with increased prevalence of syphilitic ulcers (P=.001). Sixteen patients (8%) were clinically diagnosed with lymphogranuloma venereum (LGV); 1 plausible case of LGV was found by MIF. In Madagascar, primary care of genital ulcers should include syndromic treatment for syphilis and chancroid.

Genital ulcers: etiology, clinical diagnosis, and associated human immunodeficiency virus infection in Kingston, Jamaica

Individuals presenting consecutively with genital ulcers in Kingston, Jamaica, underwent serological testing for human immunodeficiency virus (HIV) infection, chlamydial infection, and syphilis. Ulcer material was analyzed by multiplex polymerase chain reaction (M-PCR) analysis. DNA from herpes simplex virus (HSV), Haemophilus ducreyi, and Treponema pallidum was detected in 158 (52.0%), 72 (23.7%), and 31 (10.2%) of 304 ulcer specimens. Of the 304 subjects, 67 (22%) were HIV-seropositive and 64 (21%) were T. pallidum-seroreactive. Granuloma inguinale was clinically diagnosed in nine (13.4%) of 67 ulcers negative by M-PCR analysis and in 12 (5.1%) of 237 ulcers positive by M-PCR analysis (P = .03). Lymphogranuloma venereum was clinically diagnosed in eight patients. Compared with M-PCR analysis, the sensitivity and specificity of a clinical diagnosis of syphilis, herpes, and chancroid were 67.7%, 53.8%, and 75% and 91.2%, 83.6%, and 75.4%, respectively. Reactive syphilis serology was 74% sensitive and 85% specific compared with M-PCR analysis. Reported contact with a prostitute in the preceding 3 months was associated with chancroid (P = .009), reactive syphilis serology (P = .011), and HIV infection (P = .007). The relatively poor accuracy of clinical and locally available laboratory diagnoses pleads for syndromic management of genital ulcers in Jamaica. Prevention efforts should be intensified.

Etiology of genital ulcers and prevalence of human immunodeficiency virus coinfection in 10 US cities. The Genital Ulcer Disease Surveillance Group

To determine the etiology of genital ulcers and to assess the prevalence of human immunodeficiency virus (HIV) infection in ulcer patients in 10 US cities, ulcer and serum specimens were collected from approximately 50 ulcer patients at a sexually transmitted disease clinic in each city. Ulcer specimens were tested using a multiplex polymerase chain reaction assay to detect Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus (HSV); sera were tested for antibody to HIV. H. ducreyi was detected in ulcer specimens from patients in Memphis (20% of specimens) and Chicago (12%). T. pallidum was detected in ulcer specimens from every city except Los Angeles (median, 9% of specimens; range, 0%-46%). HSV was detected in >/=50% of specimens from all cities except Memphis (42%). HIV seroprevalence in ulcer patients was 6% (range by city, 0%-18%). These data suggest that chancroid is prevalent in some US cities and that persons with genital ulcers should be a focus of HIV prevention activities.

Capillary growth in relation to blood flow and performance in overloaded rat skeletal muscle

Rat extensor digitorum longus muscles were overloaded by stretch after removal of the synergist tibialis anterior muscle to determine the relationship between capillary growth, muscle blood flow, and presence of growth factors. After 2 wk, sarcomere length increased from 2.4 to 2.9 micrometers. Capillary-to-fiber ratio, estimated from alkaline phosphatase-stained frozen sections, was increased by 33% (P < 0.0001) and 60% (P < 0.01), compared with control muscles (1.44 +/- 0.06) after 2 and 8 wk, respectively. At 2 wk, the increased capillary-to-fiber ratio was not associated with any changes in mRNA for basic fibroblast growth factor (FGF-2) or its protein distribution. FGF-2 immunoreactivity was present in nerves and large blood vessels but was negative in capillaries, whereas the activity of low-molecular endothelial-cell-stimulating angiogenic factor (ESAF) was 50% higher in stretched muscles. Muscle blood flows measured by radiolabeled microspheres during contractions were not significantly different after 2 or 8 wk (132 +/- 37 and 177 +/- 22 ml. min-1. 100 g-1, respectively) from weight-matched controls (156 +/- 12 and 150 +/- 10 ml. min-1. 100 g-1, respectively). Resistance to fatigue during 5-min isometric contractions (final/peak tension x 100) was similar in 2-wk overloaded and contralateral muscles (85 vs. 80%) and enhanced after 8 wk to 92%, compared with 77% in contralateral muscles and 67% in controls. We conclude that increased blood flow cannot be responsible for initiating expansion of the capillary bed, nor does it explain the reduced fatigue within overloaded muscles. However, stretch can present a mechanical stimulus to capillary growth, acting either directly on the capillary abluminal surface or by upregulating ESAF, but not FGF-2, in the extracellular matrix.

Dorsoventral patterning in the Drosophila central nervous system: the intermediate neuroblasts defective homeobox gene specifies intermediate column identity

One of the first steps in neurogenesis is the diversification of cells along the dorsoventral axis. In Drosophila the central nervous system develops from three longitudinal columns of cells: ventral cells that express the vnd/nk2 homeobox gene, intermediate cells, and dorsal cells that express the msh homeobox gene. Here we describe a new Drosophila homeobox gene, intermediate neuroblasts defective (ind), which is expressed specifically in the intermediate column cells. ind is essential for intermediate column development: Null mutants have a transformation of intermediate to dorsal column neuroectoderm fate, and only 10% of the intermediate column neuroblasts develop. The establishment of dorsoventral column identity involves negative regulation: Vnd represses ind in the ventral column, whereas ind represses msh in the intermediate column. Vertebrate genes closely related to vnd (Nkx2.1 and Nkx2.2), ind (Gsh1 and Gsh2), and msh (Msx1 and Msx3) are expressed in corresponding ventral, intermediate, and dorsal domains during vertebrate neurogenesis, raising the possibility that dorsoventral patterning within the central nervous system is evolutionarily conserved.

An investigation of genital ulcers in Jackson, Mississippi, with use of a multiplex polymerase chain reaction assay: high prevalence of chancroid and human immunodeficiency virus infection

In 1994, an apparent outbreak of atypical genital ulcers was noted by clinicians at the sexually transmitted disease clinic in Jackson, Mississippi. Of 143 patients with ulcers tested with a multiplex polymerase chain reaction (PCR) assay, 56 (39%) were positive for Haemophilus ducreyi, 44 (31%) for herpes simplex virus, and 27 (19%) for Treponema pallidum; 12 (8%) were positive for > 1 organism. Of 136 patients tested for human immunodeficiency virus (HIV) by serology, 14 (10%) were HIV-seropositive, compared with none of 200 patients without ulcers (P < .001). HIV-1 DNA was detected by PCR in ulcers of 6 (50%) of 12 HIV-positive patients. Multivariate analysis indicated that men with chancroid were significantly more likely than male patients without ulcers to report sex with a crack cocaine user, exchange of money or drugs for sex, and multiple sex partners. The strong association between genital ulcers and HIV infection in this population highlights the urgency of preventing genital ulcers in the southern United States.

Molecular methods for the diagnosis of genital ulcer disease in a sexually transmitted disease clinic population in northern Thailand: predominance of herpes simplex virus infection

A multiplex polymerase chain reaction (M-PCR) assay that simultaneously detects the three major causes of genital ulcer disease (GUD), Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus, was used to evaluate swab specimens for 38 sequential patients with GUD at a Thai sexually transmitted disease clinic. Subjects received clinical diagnoses and syndromic treatment. Swab specimens for H. ducreyi cultures and M-PCR were obtained. No H. ducreyi cultures were positive. Of 38 M-PCR specimens, 31 (81.6%) were positive for HSV, 1 (2.3%) for both HSV and T. pallidum, and none for H. ducreyi or T. pallidum alone; 6 (15.8%) were negative for all 3 pathogens. Clinical diagnoses corresponded poorly to M-PCR findings; none of 5 suspected cases of chancroid were positive by M-PCR and none of 1 for syphilis, but 21 of 24 suspected herpes lesions were confirmed by M-PCR. Human immunodeficiency virus infection status was known for 24 of 38 subjects; 11 (45.8%) were seropositive, and all 11 had HSV by M-PCR. HSV appeared to be the most common pathogen overall.

Molecular characterization of a fucosyltransferase encoded by Schistosoma mansoni

The glycans of schistosomes include many complex carbohydrates that contain fucose. Although the biological functions of these complex carbohydrates are not yet clearly understood, some of these structures are thought to play essential roles in the life cycle of the parasite. Here we present the molecular cloning and characterization of a fucosyltransferase of Schistosoma mansoni with a DNA sequence similarity of 84.6 and 63.7% to mouse and human fucosyltransferase type VII. Southern blot analysis of genomic DNA indicated that this S. mansoni fucosyltransferase is the product of a single gene. The schistosome cDNA sequence that we obtained contains an open reading frame encoding a protein of 351 amino acids with a predicted molecular size of 40.5 kDa. From the amino acid sequence, we predicted two potential N-linked and one O-linked glycosylation site. Western blot studies of extracts from stably transfected CHO cells showed a band corresponding to the schistosome fucosyltransferase at 50 kDa, suggesting that the enzyme is indeed glycosylated. We further demonstrated the expression and enzymatic activity of the fucosyltransferase in the transfected cells by immunofluorescence studies and flow microfluorimetric analysis, which indicated that the enzyme is capable of synthesizing the SLeX blood group determinant but not the LeX determinant in CHO cells. The identification of a fucosyltransferase type VII in schistosomes further underscores the importance of fucose-containing glycans in schistosome glycobiology.

Endothelial cell stimulating angiogenesis factor

Endothelial cell stimulating angiogenesis factor (ESAF) is a small (> 1000 Da) dialysable non-peptide molecule with potent angiogenic activity. ESAF activates the major pro-matrix metalloproteinases and also uniquely reactivates the complex of these active enzymes with their tissue inhibitors resulting in both active enzyme and inhibitor. These actions may be pivotal in its role as an angiogenic factor. ESAF is primarily involved in angiogenic conditions where inflammatory cells are not evident such as foetal bone growth and electrically stimulated skeletal muscles and proliferative retinopathy. However, high levels also occur in actively growing human intracranial tumours but it is not noticeably elevated in rheumatoid arthritic synovial fluid. Its extreme potency and low molecular mass make its structural determination difficult. Possible therapeutic applications would be in the treatment of ischaemic ulcers, acceleration of fracture repair, infertility and more modestly in the correction of baldness. Analogues of ESAF could be of value in treating angiogenic diseases such as psoriasis and proliferative retinopathy.

Bridging of beta-catenin and glycogen synthase kinase-3beta by axin and inhibition of beta-catenin-mediated transcription

Axin antagonizes the developmental effects of Wnt in vertebrates. We show here that Axin simultaneously binds two components of the Wnt pathway, beta-catenin and its negative regulator glycogen synthase kinase-3beta. In mammalian cells, Axin inhibits Wnt-1 stimulation of beta-catenin/lymphoid enhancer factor 1-dependent transcription. Axin also blocks beta-catenin-mediated transcription in colon cancer cells that have a mutation in the adenomatous polyposis coli gene. These findings suggest that Axin, by forming a complex with beta-catenin and glycogen synthase kinase-3beta, can block signaling stimulated by Wnt or by adenomatous polyposis coli mutations.

Comparison of clinical diagnosis and standard laboratory and molecular methods for the diagnosis of genital ulcer disease in Lesotho: association with human immunodeficiency virus infection

A multiplex polymerase chain reaction (M-PCR) assay for Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus (HSV) was compared with clinical and standard laboratory methods for the diagnosis of genital ulcer disease (GUD) in 105 patients; 36% were human immunodeficiency virus (HIV)-seropositive. Chancroid (80%), syphilis (8%), and genital herpes (8%) were the most frequent diagnoses. H. ducreyi and HSV were isolated from ulcers of 43% and 18% of patients, respectively; in 35%, all cultures were negative and the laboratory diagnosis indeterminate. M-PCR detected H. ducreyi, T. pallidum, and HSV in 56%, 23%, and 26% of patients, respectively; (no definitive diagnosis, 6%). The proportion of patients with more than one agent was 4% by culture and 17% by M-PCR (P = .002). Resolved sensitivities of M-PCR for H. ducreyi and HSV cultures were 95% and 93%, respectively. The sensitivities of H. ducreyi and HSV cultures were 75% and 60%, respectively. HSV, detected in 47% of specimens from HIV-infected versus 16% from HIV-uninfected patients (P < .001), may be emerging as a more frequent cause of GUD.

Endothelial-cell-stimulating angiogenesis factor (ESAF) activates progelatinase A (72 kDa type IV collagenase), prostromelysin 1 and procollagenase and reactivates their complexes with tissue inhibitors of metalloproteinases: a role for ESAF in non-inflammatory angiogenesis

Endothelial-cell-stimulating angiogenesis factor (ESAF) has been shown to activate procollagenase and reactivate complexes of collagenase and gelatinase A with tissue inhibitor of metallo-proteinase (TIMP)-1. In the present paper we show a purification protocol for bovine pineal ESAF and that purified ESAF activates progelatinase A and prostromelysin-1. Unlike the activation of procollagenase by plasmin/plasminogen activator, which requires the presence of stromelysin for full activation, ESAF is able to activate fully all three proenzymes. Purified ESAF is also shown to reactivate the complexes of gelatinase A, collagenase and stromelysin-1 with TIMP-2. Once separated, both enzyme and inhibitor are active; however, ESAF binds to the enzyme in a manner preventing it from further inhibition by TIMP. ESAF is the only physiological molecule able to reactivate the TIMP/enzyme complex.

Endothelial stimulating angiogenic factor in early fracture healing

The early vascular response is essential for the normal progress of fracture healing and fracture site blood flow has been shown to reach a peak in the first two weeks after injury. Angiogenesis is an important step in this response as new vessel formation is necessary to vascularize the fracture haematoma and the fracture gap. Changes in serum levels of a low molecular weight endothelial stimulating angiogenic factor (ESAF) have been previously reported in a group of four patients with tibial fractures. In this group, ESAF levels were measured on three occasions only and at different time intervals. We present a more detailed profile of serum ESAF level changes in the first 14 days after the fracture.

Simultaneous PCR detection of Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus types 1 and 2 from genital ulcers

A multiplex PCR (M-PCR) assay with colorimetric detection was devised for the simultaneous amplification of DNA targets from Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus (HSV) types 1 and 2. By using target-specific oligonucleotides in a microwell format, 298 genital ulcer swab specimens collected in New Orleans during three intervals from 1992 through 1994 were evaluated. The results of the M-PCR assay were compared with the results of dark-field microscopy and H. ducreyi culture on two different culture media. HSV culture results were available for 99 specimens collected during the third interval. Confirmatory PCR assays targeting different gene sequences for each of the three organisms were used to validate the M-PCR results. Specimens were resolved as positive for the determination of sensitivity if the reference diagnostic test was positive or if the results of both the M-PCR and the confirmatory PCR were positive. The resolved sensitivities of M-PCR for HSV, H. ducreyi, and T. pallidum were 100, 98.4, and 91%, respectively. The resolved sensitivities of HSV culture, H. ducreyi culture, and dark-field microscopy were 71.8, 74.2, and 81%, respectively. These results indicate that the M-PCR assay is more sensitive than standard diagnostic tests for the detection of HSV, H. ducreyi, and T. pallidum from genital ulcers.

Factors involved in capillary growth in the heart

Growth of capillaries in the heart occurs under physiological circumstances during endurance exercise training, exposure to high altitude and/or cold, and changes in cardiac metabolism or heart rate elicited by modification of thyroid hormone levels. Capillary growth in all these conditions can be linked with increased coronary blood flow, decreased heart rate, or both. This paper brings evidence that, although increased blood flow due to long-term administration of coronary vasodilators results in capillary growth, a long-term decrease in heart rate induced by electrical bradycardial pacing in rabbits and pigs, or by chronic administration of a bradycardic drug, alinidine, in rats, stimulates capillary growth with little or no change in coronary blood flow. Decreased heart rate results in increased capillary wall tension, increased end-diastolic volume and increased force of contraction, and thus stretch of the capillary wall. This could lead to release of various growth factors possibly stored in the capillary basement membrane. Correlation was found between capillary density (CD) and the levels of low molecular endothelial cell stimulating angiogenic factor (ESAF) both in rabbit and pig hearts with CD increased by pacing. There was no relation between expression of mRNA for basic fibroblast growth factor and CD in sham-operated and paced rabbit hearts. In contrast, mRNA for TGF beta was increased in paced hearts, and the possible role of this factor in the regulation of capillary growth induced by bradycardia is discussed.

Low-molecular-mass endothelial cell-stimulating angiogenic factor in relation to capillary growth induced in rat skeletal muscle by low-frequency electrical stimulation

The involvement of endothelial cell-stimulating angiogenic factor (ESAF) in capillary growth was studied in adult rat skeletal muscles (tibialis anterior, TA, and extensor digitorum longus, EDL) in which capillary growth was induced by chronic unilateral electrical stimulation (10 Hz, 8 h/day for 7 days), and in sham-operated and unoperated control muscles. ESAF was assayed by its ability to activate latent collagenase in units per hour per milligram protein. Anatomical capillary density (CD, number of capillaries per mm2) and capillary per fibre ratio (C/F) were estimated in frozen sections from the same muscles after staining for endothelial alkaline phosphatase. In control muscles, ESAF levels were inversely related to capillary supply, being highest (1.82 +/- 0.25 units) in the glycolytic cortex of TA (CD 273 +/- 18/mm2, C/F 1.26 +/- 0.07), lowest (1.04 +/- 0.02 units) in its oxidative highly capillarized core (CD 862 +/- 60/mm2, C/F 2.05 +/- 0.04), and intermediate in EDL (ESAF 1.59 +/- 0.37 units, CD 527 +/- 26/mm2, C/F 1.44 +/- 0.06). Neither capillary supply nor ESAF levels were affected by sham operation. However, chronic electrical stimulation increased capillary supply significantly in EDL (CD 61% greater than in controls, C/F 45% greater) and ESAF levels were elevated 3-fold to 4.77 +/- 0.74 units. In TA muscles, stimulation increased capillary supply specifically in the glycolytic cortex (C/F 2.51 +/- 0.09, p < 0.0001 vs. control) and ESAF levels were increased significantly in this region to 3.19 +/- 0.55 units (p < 0.05, vs. control). C/F ratio and ESAF in the oxidative core of TA (2.31 +/- 0.05 and 1.48 +/- 0.23 units, respectively) were not significantly different from control values. Thus, chronic electrical stimulation, which is known to increase both shear stress and wall tension in capillaries and induce angiogenesis, also increased ESAF activity.

Multiplex PCR assay and simple preparation method for stool specimens detect enterotoxigenic Escherichia coli DNA during course of infection

Infection with enterotoxigenic Escherichia coli (ETEC) is a common cause of diarrhea among travelers and residents of developing countries. ETEC produces either a heat-stable toxin or a heat-labile toxin, or both, encoded by plasmid-borne ST and LT genes, respectively. Diagnosis of infection with this subclass of E. coli can be performed with oligonucleotide hybridization probes; however, the sensitivity and specificity of this method are insufficient. A nonradioactive multiplex PCR assay that provides a sensitive and specific method for detecting the presence of either or both toxin genes has been developed. A simple procedure that removed inhibitors of the PCR while efficiently releasing ETEC DNA from stool specimens for subsequent amplification was used. The results for samples from a human volunteer study of ETEC infection indicated that this method of sample preparation results in greater clinical sensitivity than conventional total nucleic acid extraction and ethanol precipitation. Detection of ETEC by a multiplex PCR assay in stool specimens directly processed with a glass matrix and chaotropic solution had greater sensitivity than culture.

Measurement of serum angiogenic factor in devascularized experimental tibial fractures

Early recovery of the vasculature is of profound importance in healing fractures, but the exact role of the regenerating endothelium remains controversial. Serum activity of endothelial cell-stimulating angiogenesis factor (ESAF) was measured after tibial osteotomy in two groups of sheep over a period of 42 days. Each osteotomy was held in an instrumented external fixator, and in one group the musculoperiosteal vasculature was excluded from the osteotomy site. In the well-vascularized group (n = 4), ESAF activity was significantly higher 2-5 days after osteotomy, with a peak at 4 days (21.1 +/- 5.4, p < 0.05), and displayed a biphasic pattern of secretion with a second peak at 7 days (24.3 +/- 5.5). In the devascularized group (n = 4) overall activity was lower, with only a single peak occurring at 9 days (17.5 +/- 3.2). These findings were correlated with significant differences in structural properties and on histological examination. The early detection of such regional vascular responses may prove to be of significant clinical value in high-energy trauma, enabling prediction of those fractures at risk of delayed or nonunion.

DNA probes and PCR for diagnosis of parasitic infections

DNA probe and PCR-based assays to identify and detect parasites are technically complex; however, they have high sensitivity, directly detect parasites independent of the immunocompetence or previous clinical history of the patient, and can distinguish between organisms that are morphologically similar. Diagnosis of parasites is often based on direct detection by microscopy, which is insensitive and laborious and can lack specificity. Most PCR-based assays were more sensitive than DNA probe assays. The development of PCR-based diagnostic assays requires multiple steps following the initial selection of oligonucleotide primers and reporter probe. Generally, the ability to detect the DNA of one parasite was attained by PCR; however, advances in the preparation of samples for PCR (extraction of DNA while removing PCR inhibitors) will be required to achieve that sensitivity with human specimens. Preliminary PCR systems have been developed for many different parasites, yet few have been evaluated with a large number of clinical specimens and/or under field conditions. Those evaluations are essential for determination of clinical and field utility and performance and of the most appropriate application of the assay. Several situations in which PCR-based diagnosis will result in epidemiologic, medical, or public health advances have been identified.

Specific detection of Clostridium difficile toxin A gene sequences in clinical isolates

The polymerase chain reaction (PCR) was used to specifically detect toxin A gene sequences of Clostridium difficile in DNA isolated from human faeces. A set of oligonucleotide primers derived from the non-repetitive region of the toxin A gene was developed to amplify a 634-bp DNA fragment. All 28 cytotoxic strains of C. difficile, previously characterized by a toxin B-PCR assay, were positive for the presence of toxin A gene sequences. No amplification products were obtained from DNAs extracted from non-toxigenic strains, strains of C. sordellii, or C. bifermentans. In addition, amplification of DNA extracted from C. difficile 8864, a strain which does not produce toxin A, resulted in multiple bands which probed negative for toxin A gene sequences. DNAs extracted from nine stool specimens which were positive for toxin B by the cytotoxicity assay and by the toxin B-PCR assay were also positive in this assay. Toxin A gene sequences were detected in DNAs obtained from 4/11 stool specimens which were negative by the toxin B cytotoxicity assay. These four specimens were from patients who had a history of relapses due to C. difficile-associated colitis, and whose stools had previously been found to be positive by the toxin B-PCR test despite no detectable toxin B in the specimens. These data indicate a comparable degree of clinical sensitivity between these two toxin-gene PCR-based assays. This rapid, sensitive and specific assay may be useful not only in the diagnosis of C. difficile infections, but also in molecular studies of the toxin A gene in C. difficile strains.

Anisotropy and Coherent Vortex Structures in Planetary Turbulence

High-resolution numerical simulations were made of unforced, planetary-scale fluid dynamics. In particular, the simulation was based on the quasi-geostrophic equations for a Boussinesq fluid in a uniformly rotating and stably stratified environment, which is an idealization for large regions of either the atmosphere or ocean. The solutions show significant discrepancies from the long-standing theoretical prediction of isotropy. The discrepancies are associated with the self-organization of the flow into a large population of coherent vortices. Their chaotic interactions govern the subsequent evolution of the flow toward a final configuration that is nonturbulent.

Endothelial cell stimulating angiogenesis factor--a new biological marker for disease activity in ankylosing spondylitis?

Endothelial cell stimulating angiogenesis factor (ESAF) is raised in conditions of neovascularization, such as may occur at the endochondral surface of the bone growth plate or in association with syndesmophyte formation. Syndesmophytes are formed in response to chronic enthesitis. Twenty unselected patients with AS were studied and enthesitis was measured clinically using a previously validated enthesitis index. Biochemical and haematological markers of disease activity were measured along with ESAF. Radiographs were scored for the degree of sacroiliitis and syndesmophyte formation and all these measurements were correlated to the enthesitis index. ESAF was raised in AS compared with normal controls. ESAF correlated positively with the enthesitis index but not with any of the biochemical or haematological indices. Higher levels of ESAF were found in those with more advanced sacroiliitis. High ESAF activity may be reflecting the angiogenic process involved in new bone formation associated with sacroiliitis and syndesmophyte formation. ESAF may be a biochemical marker for disease activity in AS.

Raised endothelial cell stimulating angiogenesis factor in ankylosing spondylitis

Endothelial cell stimulating angiogenesis factor (ESAF) is important in the neovascularisation that precedes new bone formation, and raised levels are found in association with healing fractures and osteoarthritis. We investigated its relevance to the new bone growth that is found at inflammatory sites in ankylosing spondylitis (AS). Forty-one patients with AS were studied clinically and radiographically and had their serum ESAF levels measured. In comparison to age-matched controls the AS patients had significantly raised ESAF levels (p < 0.0001). Within the AS group, patients with relatively higher ESAF levels had no characteristic clinical or radiological features.

Collagenase and gelatinase production by calcifying growth plate chondrocytes

The regulation of cartilage resorption is important both in cartilage pathophysiology and angiogenesis. Previous work has identified a link between calcification and activation of collagenolysis. The aim here was to test whether production of collagenase itself is also calcification-dependent, using a high-density growth plate chondrocyte culture model of calcification. Ultrastructural studies indicated that calcification occurred around large hypertrophic cells. There was no indication of phagocytosis of crystals even by cells lying next to mineral aggregates, although remodeling of the organic matrix by cell processes was evident. Release of collagenase activity increased dramatically between 24 and 48 h postcalcification, from low or undetectable basal levels. In contrast, gelatinase production was not calcification-dependent. Collagenase was released almost entirely in the latent form, being a consequence of increased protein synthesis rather than activation of existing enzyme. This linkage of calcification with latent collagenase production represents part of a coordinated remodeling of both collagenous and mineral components of the matrix which may also extend, in vivo, to the control of microvascular invasion and resorption.

The origin of HIV-1 isolate HTLV-IIIB

The striking similarity between the first two human immunodeficiency virus type 1 (HIV-1) isolates Lai/LAV (formerly LAV, isolated at the Pasteur Institute) and Lai/IIIB (formerly HTLV-IIIB, reported to be isolated from a pooled culture at the Laboratory of Tumor Cell Biology (LTCB) of the National Cancer Institute) provoked considerable controversy in light of the high level of variability found among subsequent HIV-1 isolates. In November 1990, the Office of Scientific Integrity at the National Institutes of Health commissioned our group to analyse archival samples established at the Pasteur Institute and LTCB between 1983 and 1985. Retrospective analyses have shown that contamination of a culture derived from patient BRU by one from patient LAI was responsible for the provenance of HIV-1 Lai/LAV; the contaminated culture (M2T-/B) was sent to LTCB in September 1983. Our goals were to determine which HIV-1 variants were present in the samples and the sequence diversity among HIV-1 isolates from the earliest stages of the AIDS epidemic. We examined archival specimens and report here the detection of six novel HIV-1 sequences in the cultures used to establish the pool: none is closely related to HIV-1 Lai/IIIB. A sample derived from patient LAI contained variants of both HIV-1 Lai/IIIB and HIV-1 Lai/LAV, and a sequence identical to a variant of HIV-1 Lai/IIIB was detected in the contaminated M2T-/B culture. We conclude that the pool, and probably another LTCB culture, MoV, were contaminated between October 1983 and early 1984 by variants of HIV-1 Lai from the M2T-/B culture. Therefore, the origin of the HIV-1 Lai/IIIB isolate also was patient LAI.

Specific detection of toxigenic strains of Clostridium difficile in stool specimens

Clostridium difficile is the infectious agent responsible for antibiotic-associated colitis. We report the use of the polymerase chain reaction technique to identify toxigenic strains of C. difficile in human stool specimens. A set of primers based on the nucleotide sequence of the toxin B gene, which amplified a 399-bp fragment from isolates producing toxin B, was designed. We examined 28 known toxigenic strains, which were all positive by this assay. DNAs from the nontoxigenic strains examined and from strains of Clostridium sordellii and C. bifermentans were not amplified with these primers. The sensitivity of this assay allowed us to identify as little as 10% toxigenic C. difficile cells in the presence of 90% nontoxigenic cells and to detect the toxin B gene in 1 pg of DNA from a toxigenic strain. DNAs extracted from 18 clinical stool specimens that were positive for toxin B by the tissue culture cytotoxicity assay were also positive by this assay. In addition, we detected toxin B sequences in DNA from 2 of 18 stool specimens that were negative for toxin B by the cytotoxicity assay. These two stool specimens were from patients who had a clinical pattern of colitis that was compatible with C. difficile causation. This rapid, sensitive assay will be useful for specific identification of toxigenic C. difficile and for revealing cases that are undetected by analysis of fecal samples for toxin B alone.

Classification of subgroups of Giardia lamblia based upon ribosomal RNA gene sequence using the polymerase chain reaction

A sensitive and specific polymerase chain reaction-based assay has been developed to detect and analyze polymorphism in the Giardia lamblia 18S ribosomal RNA gene. Efficient amplification required the inclusion of cosolvents (glycerol and dimethyl sulfoxide) in the reaction. Following the optimization of conditions for amplification and subsequent hybridization of amplified product with radiolabeled oligonucleotide probe, a detection limit of less than one organism's worth of DNA was achieved. Thirty-five different G. lamblia strains obtained from various human and animal host types and geographic locations were analyzed by this method. The strains could be divided into 3 groups on the basis of defined nucleotide substitutions within the 183-bp amplified DNA fragment of the 18S ribosomal RNA gene. The groupings based upon the 18S ribosomal RNA gene sequence correlated with groupings previously assigned based upon patterns of surface antigens and restriction enzyme analysis. Analysis of the G. lamblia 18S ribosomal RNA gene sequences present in fecal specimens obtained from giardiasis patients revealed the presence of the different sequence types in these specimens. Some specimens contained more than one sequence type. The identification of subgroups of G. lamblia may facilitate studies of virulence, infectivity, and the epidemiology of giardia infection.

Characterization of a series of novel fucose-containing glycosphingolipid immunogens from eggs of Schistosoma mansoni

Lipid extracts of eggs, worms, and cercariae of the parasitic trematode Schistosoma mansoni have been shown to contain a large number of highly immunogenic glycolipids (Weiss, J. B., Magnani, J. L., and Strand, M. (1986) J. Immunol. 136, 4275-4282). Three fractions of schistosome egg glycolipids were selected on the basis of their reactivity with an anti-schistosome monoclonal antibody (128C3/3), which recognizes a developmentally regulated carbohydrate epitope present on both glycolipid and glycoprotein antigens from S. mansoni. These fractions were purified by silica gel chromatography and preparative high performance thin layer chromatography and characterized by monosaccharide, fatty acid, and linkage analysis with gas chromatography-mass spectrometry, as well as by positive and negative ion fast atom bombardment-mass spectrometry. The immunogens were shown to be glycosphingolipids having homologous structures based on a highly novel extension of glucosylceramide. Monosaccharide inhibition studies indicated that the epitope recognized by 128C3/3 residues in an outer region of the immunogens consisting of Fuc2GlcNAc (where Fuc is fucose) repeating units. The largest antigen characterized may have the following structure, based on the evidence presented in this paper. [sequence: see text] The evidence indicated the existence of a series of glycan structures created by deletions of one or more Fuc1----3 side chains from the above structure.

Concentrations of endothelial-cell-stimulating angiogenesis factor, a major component of human uterine angiogenesis factor, in human and bovine embryonic tissues and decidua

Embryonic development involves the establishment of new patterns of vascular growth in the fetus and within the lining of the womb. A factor, human uterine angiogenesis factor, has been purified from the decidua and stimulates the growth of blood vessels in collagen sponge implants and in the chick chorioallantoic membrane. Evidence is presented that suggests that a major active component of human uterine angiogenesis factor is an activator of latent matrix metalloproteinases, of low M(r), called endothelial-cell-stimulating angiogenesis factor and that this factor is present in substantial quantities in a number of embryonic tissues.

Increased endothelial cell stimulating angiogenesis factor in patients with tibial fractures

Angiogenesis is an important step in the normal process of fracture healing, irrespective of the method of fixation. Using a quantitative assay, the amount of endothelial cell stimulating factor (ESAF) has been determined in a small group of patients with tibial fractures. ESAF levels were found to be increased when compared with normal volunteers, although this increase was relatively less in fractures held with intramedullary nails than with external fixation.

Elevated endothelial-cell-stimulating angiogenic factor activity in rodent glycolytic skeletal muscles

1. Capillary density is greater in skeletal muscles comprised of predominantly oxidative (type I) fibres than in those comprised of mainly glycolytic (type II) fibres. In order to investigate further the angiogenic mechanisms involved in muscle capillarization, endothelial-cell-stimulating angiogenic factor activities in various rodent skeletal muscles were compared. 2. Eleven untrained adult male Wistar rats were killed and the predominantly oxidative (type I) muscle,s soleus and heart, the predominantly glycolytic (type II) muscle, extensor digitorum longus, and the mixed-fibre muscle, gastrocnemius, were removed. Each sample was separately homogenized and centrifuged and the supernatants were diafiltered to isolate the low-molecular-mass fraction containing endothelial-cell-stimulating angiogenic activity. This was assayed for its ability to activate latent collagenase and was expressed as units, where 1 unit represents the percentage activation of the enzyme h-1 (mg of protein in the supernatant)-1. 3. The results (medians and ranges) demonstrated significantly greater endothelial-cell-stimulating angiogenic factor activity in extensor digitorum longus muscle (2.14 units, 0.62-2.87 units, n = 13) than in soleus (0.82 units, 0.59-1.79 units, n = 15), gastrocnemius (0.34 units, 0.28-0.40 units, n = 4) or heart (0.43 units, 0.16-0.52 units, n = 11) (P less than 0.01 for each) muscle. 4. These findings suggest that endothelial-cell-stimulating angiogenic activity in muscle is either inversely or not related to the local capillary density, which may be at or near a maximum in physiologically contracting, predominantly oxidative muscles.

Raised levels of latent collagenase activating angiogenesis factor (ESAF) are present in actively growing human intracranial tumours

Endothelial cell stimulating angiogenesis factor (ESAF) is a potent, low molecular mass mitogen, specific for endothelial cells. In common with various protein growth factors, it displays angiogenic activity in a variety of biological test systems. However, it differs from these other factors by virtue of its low molecular mass and its ability to activate latent matrix metalloproteinases in a dose dependent manner. This activity has been used to quantify the factor in both normal and diseased brain tissue. The concentration of ESAF determined in biopsies from different types of intracranial tumours varied: in some tumour types the level was close to that of control samples whereas in others it rose to levels comparable to those encountered in the pineal gland, the richest source of ESAF in mature mammals. Tumours considered to be benign contained significantly less ESAF than those neoplasms classified as being malignant (P = 0.025). There was also a correlation between the mitotic activity of tumour samples, as determined by conventional H & E histochemical staining and the ESAF concentration present. These findings agree with previous studies in which elevated ESAF levels have been found in tissue where proliferation of vascular elements has been observed.

Activation of the matrix metalloproteinase inhibitor complex by a low molecular weight angiogenic factor

Tissue inhibitor of matrix metalloproteinases is the major inhibitor of the collagenolytic enzymes and the inhibitory complex has been thought to be irreversible. In this paper we show that a low molecular weight non-protein endothelial cell stimulating angiogenic factor is able to reactivate the enzyme from the inhibitor complex and liberate free inhibitor. The importance of an angiogenic factor able to initiate limited degradation of extra-cellular matrix such that space is created for new capillary growth is discussed.

Low molecular weight angiogenesis factors

A number of substances have been proposed for the role of angiogenesis factors. Many of these are of protein origin and are therefore amenable to the tools of the molecular biologist. However a number of low molecular weight angiogenesis factors are emerging as important initiators and/or cofactors of neovascularization. Of these a number are known to stimulate angiogenesis indirectly, possibly through an inflammatory response. Some putative angiogenic factors stimulate microvessel endothelial cells nonspecifically, also causing migration and proliferation of large vessel cells. Others are specific for microvessel cells either for stimulating migration, proliferation or both. The nature and action of the low molecular weight factors in vivo and in vitro are reviewed.

Production of endothelial cell stimulating angiogenesis factor (ESAF) by chondrocytes during in vitro cartilage calcification

The aim of this study was to identify the stimulus for production of the latent collagenase and angiogenic activator ESAF by growth plate chondrocytes. Stimulation correlated most closely with matrix calcification. Alkaline phosphatase was necessary for calcification (and so stimulation of ESAF production) but we could find no evidence for a direct link with ESAF production. ESAF production was also stimulated by addition of preformed mineral to non-calcified cultures but was inhibited by dexamethasone. Protein synthesis was necessary for the stimulation of ESAF production by calcification, though ESAF is not itself a protein. Based on these findings we suggest that chondrocytes, at a suitable stage of maturation in the growth plate, are stimulated to produce ESAF by the proximity of crystals in the matrix. Stimulation, which may consist of the induction of an enzyme or transport protein, leads to the release of this potent activator of collagenolysis as part of the angiogenic cascade.

Measurement of blood flow in the chick egg yolk sac membrane

Blood vessels of the yolk sac membrane are the transport route by which a chick embryo obtains nutrients from the egg yolk. After 4 days of incubation at 37 degrees C a sparse network of blood vessels are visible within the membrane and they become denser over the following days. The preparation has been used to assess angiogenesis. Using visual inspection to assess the growth of new vessels towards pellets of test substances placed on the membrane surface, responses are judged negative or positive. Laser Doppler flowmetry has been used to investigate the potential of this technique to quantify blood flow through the yolk sac membrane. Measurements have been taken from capillary beds and single larger vessels over a range of temperatures and from avascular yolk and egg white using a Perimed PF3 with PF310 bent-tipped probe. Capillary beds exhibited vasomotion (about one cycle per minute) and oscillations of longer duration (about five cycles per hour). Cardiac pulses, strongly present in larger vessels (mean 90 pu, pulse 75 pu), were not easily identified in the capillary bed. Avascular yolk measurements gave flux values (due to Brownian motion of yolk proteins) which were greater than for capillary beds but without oscillations. Angiogenesis was stimulated by pellets containing 2 micrograms of basic fibroblast growth factor. There were significant increases in single vessel blood flow after 24 h compared with blank control pellets placed on the same egg.

The folding properties of the Escherichia coli maltose-binding protein influence its interaction with SecB in vitro

It has been proposed that the cytoplasmic SecB protein functions as a component of the Escherichia coli protein export machinery by serving as an antifolding factor that retards folding of the precursor maltose-binding protein (preMBP) into a translocation-incompetent form. In this study, it was found that SecB directly interacts with wild-type preMBP and various mutationally altered MBP species synthesized in vitro to form a SecB-MBP complex that can be precipitated with anti-SecB serum. The association of SecB with wild-type preMBP was relatively unstable; such a complex was formed only when SecB was present cotranslationally or after denaturation of previously synthesized preMBP and was detected with only low efficiency. In marked contrast, MBP species that were defective in the ability to assume the stable conformation of wild-type preMBP or that exhibited significantly slower folding kinetics formed much more stable complexes with SecB. In one case, we demonstrated that SecB did not need to be present cotranslationally for complex formation to occur. Formation of a complex between SecB and MBP was clearly not dependent on the MBP signal peptide. However, we were unable to detect complex formation between SecB and MBP lacking virtually the entire signal peptide but having a completely intact mature moiety. This MBP species folded at a rate considerably faster than that of wild-type preMBP. The propensity of this mutant protein to assume the native conformation of mature MBP apparently precludes a stable association with SecB, whereas an MBP species lacking a signal peptide but exhibiting altered folding properties did form a complex with SecB that could be precipitated with anti-SecB serum.