Topically applied recombinant tissue plasminogen activator for the treatment of venous ulcers. Preliminary report

BACKGROUND

Increasing evidence suggests that fibrin deposition is an important pathogenic component of venous ulceration and that fibrin removal could accelerate ulcer healing.

OBJECTIVE

We sought to determine whether topical application of recombinant tissue plasminogen activator (tPA) compounded in 1% hyaluronate acid (HA) can be used safely in venous ulcers and whether it can accelerate healing.

METHODS

Twelve patients were randomized in a double-blind fashion in three sequential groups of four subjects each, so as to receive daily topical application of either placebo (HA alone, one patient) or tPA/HA (three patients) at escalating doses of 0.25, 0.5, and 1.0 mg/ml of tPA for 4 weeks.

RESULTS

No safety problems occurred, and we found a close direct correlation between mean ulcer reepithelialization, fibrin removal, and the dose of topically applied tPA (r = 0.991).

CONCLUSION

In this first study to examine its usefulness, topically applied tPA appears to be a safe and promising agent for treating venous ulcers.

Base-boronated dinucleotides: synthesis and effect of N7-cyanoborane substitution on the base protons

Boron-modified nucleic acids comprise a new set of DNA mimics that have potential biological and therapeutic applications. A series of nine dinucleotides containing N7-cyanoborane-2'-deoxyguanosine ((7b)dG) at the 3', 5' or both positions of the phosphodiester linkage have been synthesized using solution phase phosphoramidite chemistry. Fmoc was used as the 5'-protecting group because of incompatibility of the cyanoborane moiety with 5'-DMT cations generated during the deprotection step. The presence of the cyanoborane group was confirmed on the basis of Fab-MS and 1H NMR spectroscopy. The H-8 proton of (7b)dG in the dinucleotides shifted 0.35-0.80 p.p.m. downfield relative to that of unmodified dG. A comparison of the D20 exchange kinetics of the H-8 proton at 60 degrees C showed that H-8 of (7b)dG is very labile relative to unmodified dG, indicating that the N7-cyanoborane modification increases the acidity of the H-8 proton of (7b)dG. These studies illustrate the feasibility of synthesizing boron-containing oligonucleotides which are modified at the N7-guanine to block Hoogsteen pairing in the DNA major groove.

Serum levels of immunoglobulins in thermal burns

Thermal injury is known to induce alterations in the immune system. Sixty-four patients of thermal burns have been studied for serum immunoglobulins. Concentrations of IgG, IgA and IgM were decreased immediately after injury and gradually increased up to normal limits on the 30th postburn day.

Recognition of B-cell epitopes of the 65 kDa HSP in Behçet's disease

B-cell epitopes of the mycobacterial 65 kDa heat shock protein (HSP) were mapped in sera from patients with Behçet's Disease (BD). A series of 47 overlapping synthetic peptides (15ers) derived from the sequence of the Mycobacterium tuberculosis 65 kDa HSP was used in ELISA. Significant increases in IgA and IgG antibody levels were observed with peptides 111-125, 154-172 and 311-326 in sera from BD, compared with those from controls. Homologous peptides derived from the sequence of the human mitochondrial 60 kDa HSP were then examined. Peptides 136-150 and 336-351 showed comparable results to the homologous mycobacterial peptides 111-125 and 311-326, respectively. The B-cell epitopes defined in this investigation overlap with the T-cell epitopes the authors have previously reported in BD. Inhibition studies are consistent with the view that antibodies to each of the three B-cell epitope peptides represent a small proportion of the total B-cell epitope repertoire elicited by the 65 or 60 kD HSP. Sequential antibody studies suggest that IgA and IgG antibody titres to one or all three peptides tested may increase during exacerbation of ocular disease. The functional role of these antibodies needs to be determined, but the peptides may be involved in the immunopathogenesis of BD as they can induce experimental uveitis in Lewis rats, which is a principal manifestation of BD.

Vascular complications of lung transplantation

BACKGROUND

The data on vascular anastomotic complications after single-lung and bilateral lung transplantation are scant.

METHODS

We reviewed the data on our patients having single and bilateral lung transplantation to examine our experience and management of vascular anastomotic complications.

RESULTS

We retrospectively identified 5 of 109 consecutive patients undergoing lung transplantation who had postoperative pulmonary arterial or venous obstruction. There were 4 women and 1 man (age range, 32 to 53 years). Three patients had left single-lung transplantation, 1 patient had right single-lung transplantation, and 1 patient underwent bilateral sequential lung transplantation. Complications comprised two right-sided and two left-sided pulmonary artery stenoses and one combined left pulmonary arterial and venous obstruction. Isotope perfusion scanning was used in 3 patients and suggested a vascular stenosis in all of them. Pulmonary angiography was used in each as a confirmatory test and to demonstrate anatomic details. Transesophageal echocardiography was used in 1 patient and did not detect a right pulmonary artery stenosis. One patient underwent revision of a pulmonary artery stenosis with a period of warm ischemia and subsequent fatal lung injury. Two revisions were undertaken on cardiopulmonary bypass with a cold blood flush to the transplanted lung. One venous anastomotic angioplasty with stent insertion was performed. Two patients died before treatment. All 5 patients died between 5 and 630 days postoperatively.

CONCLUSIONS

Vascular complications carry a high mortality. Reoperation, preferably using cardiopulmonary bypass and a cold blood flush technique to avoid further lung injury, is recommended. In high-risk patients, dilation or stent insertion can be considered.

Evaluation of 1-azabicyclo[2.2.2]oct-3-yl alpha-fluoroalkyl-alpha-hydroxy-alpha-phenylacetates as potential ligands for the study of muscarinic receptor density by positron emission tomography

Both 1-azabicyclo[2.2.2]oct-3-yl alpha-(1-fluoroeth-2-yl)-alpha-hydroxy-alpha-phenylacetate (FQNE, 5) and 1-azabicyclo[2.2.2]oct-3-yl alpha-(1-fluoropent-5-yl)-alpha-hydroxy-alpha-phenylacetate (FQNPe, 6) were prepared and evaluated as potential candidates for the determination of muscarinic cholinergic receptor (mAChR) density by positron emission tomography (PET). The results of in vitro binding assays demonstrated that although both 5 and 6 had high binding affinities for m1 and m2 mAChR subtypes, 6 displayed a higher affinity (nM, m1; KD, 0.45, m2; KD, 3.53) as compared to 5 (nM, m1; KD, 12.5, m2; KD, 62.8). It was observed that pretreatment of female Fisher rats with either 5 or 6 prior to the i.v. administration of Z-(-)(-)-[131I]-IQNP, a high-affinity muscarinic ligand, significantly blocked the uptake of radioactivity in the brain and heart measured 3 h postinjection of the radiolabeled ligand. These new fluoro QNB analogues represent important target ligands for evaluation as potential receptor imaging agents in conjunction with PET.

Role of gamma delta T cells in pathogenesis and diagnosis of Behcet's disease

BACKGROUND

Behcet's disease (BD) is a multisystem disorder of unknown pathogenesis. The diagnosis is based on a set of international clinical criteria. Previous investigations have suggested that immunological cross-reactivity between peptides within streptococcal heat-shock proteins and human peptides might be involved in the pathogenesis of BD. We tested four peptides from mycobacterial heat-shock proteins to see if they specifically stimulated gamma delta T cells from BD patients. We then investigated this response to see whether it could be used as a laboratory test to diagnose BD.

METHODS

We used a T-cell proliferative test to assay responses to four mycobacterial 65 kDa heat-shock-protein peptides and to four homologous peptides derived from the sequence of the human 60 kDa heat-shock protein.

FINDINGS

We elicited significant gamma delta T-cell responses to the mycobacterial peptides in 25 (76%) of 33 patients with BD, compared with 2 (3.6%) of 55 controls with recurrent oral ulcers, systemic disease, or no disorders. The proportion of BD patients who had false-negative results decreased if the test was done during clinical manifestation of disease activity. There was a correlation between disease activity and T-cell responses. Four homologous peptides from human 60 kDa heat-shock protein also specifically stimulated T cells from patients with BD but with lower stimulation indices.

INTERPRETATION

Activation of peripheral-blood mononuclear cells with the four heat-shock-protein peptides elicited significant T-cell proliferative responses by the gamma delta subset of T cells, which may regulate alpha beta T cells. Because these peptides have a high specificity for BD, this assay can be used as a laboratory diagnostic test for BD.

Healing of the bronchus in pulmonary transplantation

OBJECTIVE

To review the results of bronchial healing in a consecutive series of 100 isolated pulmonary transplants, performed at one centre between 1987 and 1994.

METHODS

A retrospective review of 123 assessable bronchi (61 in single lung and 62 in bilateral lung) transplants was carried out. All anastomoses were assessed by bronchoscopy at 7-10 days, and follow up was from one to seven years. The effect on bronchial dehiscence or stenosis requiring endobronchial stent, of suture technique, pre and post operative steroid administration, bronchial wrap, donor ischaemic time and time to first rejection episode was assessed.

RESULTS

Complications of airways healing occurred in four patients: stenosis in two and dehiscence in two (1.6% of bronchi at risk in both groups). Airway complication was not affected by steroids, pre-operative diagnosis, presence of a wrap (34 with pericardium or omentum, 89 with peribronchial tissue alone) or any other variable. There was a higher incidence of dehiscence (2/36) with continuous rather then interrupted (0/87) suture, but this was not statistically significant. There was one airway-related death. Two patients who required anastomotic stenting remain alive and well.

CONCLUSIONS

A very low complication rate can be achieved without recourse to bronchial wrapping, telescoping anastomoses or steroid avoidance. Combined heart-lung transplantation or bronchial revascularisation are not required to achieve reliable bronchial healing.

Effects of short term ischemia and reperfusion on coronary vascular reactivity and myocardial function

Ischemia and reperfusion have been shown to cause damage to the endothelium as well as to the cardiac myocyte. Although the vasodilator response has been shown to be impaired following ischemia and reperfusion, the effect of a short period of global ischemia on the contractile response of the coronary vasculature is not clear. In the present study, coronary vasoconstriction in response to U46619, PGF2 alpha, 5-HT, and KCl was found to be depressed for at least 15 min following 15 min of in vitro global ischemia in rats hearts. Vasodilator blockers or inactivators were used in an effort to restore this depressed coronary response. Indomethacin (5 microM) was used to block production of vasodilator prostaglandins, L-NAME (30 microM) to block production of nitric oxide (NO), and adenosine deaminase (2.4 units/ml of coronary flow) to inactivate adenosine. None of these agents restored the normal coronary constrictor response following ischemia. When superoxide dismutase and catalase (both 20 micrograms/ml of coronary flow) were infused for 5 min before and after ischemia, the coronary response recovered more than 100% of its preischemic value by 15 min of reperfusion, but still remained depressed at 5 min reperfusion. These data suggest that free radicals produced during ischemia and/or reperfusion may be at least partly responsible for this temporary "stunning" of the coronary vasculature. Since the impaired contractile response was still present at 5 min reperfusion when the buffer was supplemented with oxygen radical scavengers, another mechanism must also be involved in this "stunning" process.

Flavonoid glycosides and an anthraquinone from Rumex chalepensis

Besides rutin, quercetin 3-rhamnoside and kaempferol 3-rhamnosyl(1-->6) galactoside, a new flavonol glycoside, quercetin 3-glucosyl(1-->4)galactoside, and 1,6,8-trihydroxy-3-methyl anthraquinone (emodin) have been characterized from leaves of Rumex chalepensis. The structures were established on the basis of Rf values, acid hydrolysis to aglycone and sugar and UV, EI and FAB-mass spectra, 1H NMR, 13C DEPT NMR, NOE difference measurement, 1H-H COSY and 1H-13C COSY spectral data.

Bilateral sequential lung transplantation for end stage septic lung disease

BACKGROUND

Bilateral sequential lung transplantation (BSLT) has been widely adopted as an alternative to combined heart and lung transplantation for the management of end stage septic lung disease in many transplant centres.

METHODS

A retrospective review was undertaken of the first 32 consecutive patients with septic lung disease to undergo BSLT at the Freeman Hospital.

RESULTS

Between April 1988 and October 1994 32 patients underwent BSLT. Survival at 30 days was 85% and actuarial survival at one year was 70%. Improved pulmonary function was seen in all surviving patients.

CONCLUSION

BSLT for septic lung disease offers comparable survival to heart-lung transplantation, with excellent functional results. Long term results may be superior because the disadvantages of transplanting the heart are avoided.

Recognition of a unique peptide epitope of the mycobacterial and human heat shock protein 65-60 antigen by T cells of patients with recurrent oral ulcers

T cell epitopes of the 65-kD heat shock protein (hsp) were investigated in patients with recurrent oral ulcers (ROU). Peripheral blood mononuclear cells were stimulated with overlapping synthetic peptide (15ers), derived from the sequence of the 65-kD hsp of Mycobacterium tuberculosis. Specific lymphoproliferative responses were stimulated only with peptide 91-105 in ROU, compared with healthy or disease controls (P < 0.01). This was confirmed by studying 760 short term cell lines generated with the 65-kD hsp and then stimulated with the peptides. The frequency of short term cells lines responding to peptide 91-105 in ROU was significantly greater than in healthy (P < 0.0001) or disease controls (P < 0.01). A comparative investigation with the homologous human 60-kD hsp peptide 116-130 also showed significantly greater lymphoproliferative responses in ROU than in healthy (P < 0.01) or disease controls (P < 0.001). The potential involvement of the T cell epitope 91-105 in the pathogenesis of ROU is supported by finding a significant increase in the lymphoproliferative responses stimulated with peptide 91-105 during the stage of ulceration, compared with remission in 9/11 patients studied sequentially (P < 0.05). The results suggest that oral ulceration might be initiated by the microbial hsp peptide 91-105 stimulating the mucosal Langerhans cells, which may generate autoreactive T cell clones primed to the homologous peptide 116-130.

Pentoxifylline, pentifylline, and interferons decrease type I and III procollagen mRNA levels in dermal fibroblasts: evidence for mediation by nuclear factor 1 down-regulation

Pentoxifylline (PTX) is a methylxanthine that exhibits multiple biologic activities, including the inhibition of collagen synthesis by dermal fibroblasts. Because some PTX activities have recently been linked to transcription factor-mediated regulation of gene transcription, we have investigated if PTX acts to inhibit collagen synthesis at a transcriptional locus by measuring procollagen mRNA levels by assaying for the presence of an activator of procollagen gene promoters, nuclear factor (NF)-1. The effects of another methylxanthine, pentifylline (PTF), shown herein to be a tenfold more potent inhibitor of collagen synthesis than PTX, and interferon-alpha, -beta, and -gamma were studied in parallel. Analysis of extracellular protein and RNA from 48-h-treated fibroblasts showed that PTX, PTF, and interferons decreased alpha 1(I), alpha 2(I), and alpha 1(III) procollagens by reducing the steady-state levels of the corresponding procollagen mRNA transcripts. Reduction of procollagen mRNA levels appeared to be dependent on new protein synthesis, as it was prevented by treatment with cycloheximide. Assay for the presence of nuclear NF-1 by gel mobility shift analysis showed that extracts from interferon, PTX, and PTF-treated fibroblasts lacked proteins recognizing the consensus DNA binding sequence for NF-1. Taken together, these observations suggest interferons and methylxanthines may inhibit fibroblast collagen synthesis by a common mechanism requiring new protein synthesis that suppresses procollagen gene transcription through down-regulation of NF-1.

Visual fixation and smooth pursuit eye movement abnormalities in patients with schizophrenia and their relatives

Increasing evidence suggests that smooth pursuit eye movement (SPEM) dysfunction may serve as an endophenotype or genetic marker of schizophrenia. The authors tested SPEM and visual fixation (VF) in 31 patients with schizophrenia, 33 of their first-degree relatives, and 24 patients with major depressive disorder. A high rate of abnormal VF was found in schizophrenic patients and their first-degree relatives, but not in affective disorder patients with or without psychotic features. Rate of VF abnormality distinguished schizophrenic patients from acutely depressed mood disorder patients; SPEM did not. VF and SPEM performance correlated only moderately, suggesting that the pathophysiologies of these two eye movement abnormalities may be partially independent. Implications for identifying a schizophrenia endophenotype are discussed.

Mechanical ventricular assistance for the failing right ventricle after cardiac transplantation

Right ventricular failure secondary to elevated pulmonary vascular resistance (PVR) following orthotopic cardiac transplant is a complication with a high mortality; and patients with high resistance are often not accepted on transplant waiting lists. We describe six cases of right ventricular failure after cardiac transplant managed by right ventricular assist device (RVAD), four of whom died and two patients who survived following life-threatening complications.

Oncostatin M stimulates collagen and glycosaminoglycan production by cultured normal dermal fibroblasts: insensitivity of sclerodermal and keloidal fibroblasts

It is thought that normal fibrotic repair progresses to dermal fibrosis when fibroblasts are activated persistently by chronic exposure to cytokines such as transforming growth factor-beta. However, additional cytokines and mechanisms may play a role in the development of fibrosis. Thus, we examined a recently described T-lymphocyte/macrophage-derived cytokine, oncostatin M, for its effect on the production of collagen and glycosaminoglycan by microcultures of normal dermal, sclerodermal, and keloidal fibroblasts. Treatment with oncostatin M for 48 h induced dose-dependent (1-100 ng/ml) increases in the collagen and glycosaminoglycan production of nine normal fibroblast strains, which in the absence of fetal bovine serum at 100 ng/ml averaged 196% and 244%, respectively. Oncostatin M treatment increased both types I and III procollagens and their mRNA transcripts, as well as levels of hyaluronic acid, chondroitin-4/6 sulfates, and dermatan sulfate, but not fibronectin or general noncollagenous protein synthesis. In contrast, the collagen production of six of eight sclerodermal and keloidal fibroblast strains was essentially unresponsive to oncostatin M treatment, with 100 ng/ml inducing an average increase of only 34% for the eight fibrotic strains. Oncostatin M stimulation of fibrotic fibroblast glycosaminoglycan production was also hyporesponsive, as 100 ng/ml of oncostatin M induced an average increase of only 101%. These results indicate that oncostatin M could function as a stimulator of normal fibrotic repair via activation of fibroblast collagen and glycosaminoglycan synthesis and that the persistent activation of sclerodermal and keloidal fibroblasts is accompanied by a loss of sensitivity to oncostatin M stimulation.

Heat shock protein peptides reactive in patients with Behçet's disease are uveitogenic in Lewis rats

Mycobacterial and homologous human heat shock protein T cell peptide epitopes specific for T lymphocytes in Behçet's disease were investigated for their pathogenicity in Lewis rats. The potential pathogenicity of eight peptides and two controls was assessed by administering the peptides in enriched Freund's adjuvant into the footpads of male Lewis rats. Anterior uveitis which is a major manifestation of Behçet's disease was induced with two out of the four mycobacterial and all four homologous human peptides. The most effective peptides inducing iridocyclitis in 64-75% of rats were peptides with amino acids 336-351 and 136-150, derived from the sequence of the human 60-kD heat shock protein. A few of the rats also showed evidence of focal loss of photoreceptors. These results suggest that selected peptides within heat shock protein 60 kD which function as T cell epitopes in Behçet's disease are capable of inducing uveitis in rats. This supports the view that the peptide T cell determinants may be involved in the pathogenesis of Behçet's disease.

Red cell aplasia resembling Diamond-Blackfan anemia in seven children in a family

PATIENTS AND METHODS

Seven children of the same family with a possible variant of Diamond-Blackfan anemia (DBA) are reported. Five were male siblings, and the other two were their cousins, one male and one female. All were products of consanguineous marriages of healthy parents. All cases occurred within one generation. Anemia was present at birth or shortly after birth. Hepatosplenomegaly was present in all. Four had short stature. Hematological findings included normochromic, normocytic, or macrocytic anemia, marked reticulocytopenia, with initial normal white blood cell and platelet count, and absent or markedly decreased erythroid precursors on bone marrow examination. All were treated initially with prednisolone; in one patient oxymetholone was added.

RESULTS

Three children failed to respond to the initial treatment, and also failed to respond to cyclosporin A and pulse doses of methylprednisolone. Myelofibrosis occurred in two siblings, 9 and 11 years from diagnosis. In two children the disease recurred 9 and 12 years after initial diagnosis.

CONCLUSIONS

Our cases point to a possible variant of DBA characterized by the presence of normochromic normocytic anemia, hepatosplenomegaly, absent skeletal malformations, and unusual long- term complications.

Single lung transplantation with simultaneous contralateral pneumonectomy for cystic fibrosis

A 24-year-old man with cystic fibrosis and marked reduction of volume of the left hemithorax caused by skeletal asymmetry and mediastinal shift underwent successful right single lung transplantation with simultaneous left pneumonectomy. Despite significant preoperative microbiologic contamination, it proved possible to sterilize the pneumonectomy space and no airway complications occurred. Good long-term results have been achieved, and the historic assumption that single lung transplantation is unsuitable for patients with septic lung disease is challenged.

2-substituted thioadenine nucleoside and nucleotide analogues: synthesis and receptor subtype binding affinities (1)

The design, synthesis, and receptor subtype binding affinities of several 2-substituted thioadenosine nucleoside and nucleotide analogues are described. Alkylation of 2-thioadenosine (1) with iodopentenylboronic acid followed by iododeboronation gave 2-((E)-1-iodo-1-penten-5-yl) thioadenosine (9). Compound 1 on treatment with 4-nitrobenzyl bromide and propargyl bromide furnished compounds 3 and 5, respectively. The 5'-monophosphate analogues of compounds 3, 5, 7, and 9 were prepared similarly using 2-thioadenosine 5'-monophosphate (2). Treatment of 1 with bromoethylamine hydrobromide provided 2-[(aminoethyl)thio]adenosine (11) which on coupling with N-succinimidyl 3-(4-hydroxyphenyl)propionate gave 2-[[[3-(4-hydroxyphenyl)propionamido]ethyl]thio]adenosine (12). Iodination of 12 gave 2-[[[3-(4-hydroxy-3-iodophenyl)propionamido]ethyl]thio]adenosine (13). Compounds 3-13 were evaluated for their affinities toward A1 and A2 adenosine receptors in rat brain cortex and striatum, respectively using [3H]DPCPX and [3H]CGS21680 as ligands. The nucleotide analogues 4, 6, 8, and 10 inhibited binding of [3H]DPCPX by 10-20% and of [3H]CGS21680 by 40-50% at a concentration of 100 microM suggesting weak affinity toward adenosine receptors. The nucleoside analogues 3, 5, 7, 9, 12, and 13 inhibited the A2 receptor binding of [3H]CGS21680 with Ki values of 1.2-3.67 microM, while A1 receptor binding of [3H]DPCPX was inhibited with Ki values 10-17 microM. The A1/A2 ratios suggest 4-8-fold A2 receptor selectivity.

Videothoracoscopy in the diagnosis of intrathoracic pathology: early experience

We report our experience using the new technique of videothoracoscopy in the diagnosis of intrathoracic pathology. In the last 12 months, 40 patients (24 male; 16 female) have undergone investigation by this method. Lung biopsy has been performed in 17 patients, pleural biopsy in 20 patients and mediastinal biopsy in three patients. The majority had been referred after other investigations had been inconclusive. All biopsies were diagnostic except one mediastinal biopsy. This early experience suggests that videothoracoscopic biopsy is a well-tolerated technique with high diagnostic yield.