L-696,474, a novel cytochalasin as an inhibitor of HIV-1 protease. I. The producing organism and its fermentation.

A novel cytochalasin, L-696,474, (18-dehydroxy cytochalasin H) that inhibits HIV-1 protease was discovered in fermentations of a bark-inhabiting Ascomycete, Hypoxylon fragiforme. The product was first identified from extracts of an agar medium. Fermentation studies on a number of media indicated that the product can be made on several solid and liquid media. Optimum production was obtained from growth in a complex medium composed of glycerol, glucose, citrate, Ardamine, soybean meal, tomato paste, and inorganic salts. Other Hypoxylon spp., related species of Xylariales, and other fungi known to produce cytochalasins, were also surveyed for their ability to make L-696,474. Only one other Hypoxylon fragiforme isolate was found to make this novel cytochalasin; none of the other cultures surveyed made L-696,474 or any other compounds which inhibit HIV-1 protease.     

Efficacy of specimen radiography of clinically occult noncalcified breast lesions

Breast biopsy specimen radiography is required to ensure the accurate removal of clinically occult lesions discovered by mammography. Although used routinely for calcified lesions, it has not been widely accepted for those abnormalities that do not contain calcium. To determine the efficacy of film-screen specimen radiography for confirming the presence of clinically occult, noncalcified lesions, we undertook a prospective study of 104 specimen radiographs obtained after mammographically guided hookwire localization and planned excision of these lesions. Ninety-seven (93%) of the excised abnormalities were visualized on specimen mammograms. Malignancy was found in 22 (21%) of them. Thirty-five percent of the specimen radiographs showed better anatomic detail of the lesion, 48% showed the same detail, and 16% showed less detail than the original mammograms. Specimen radiographs failed to show the lesion in only seven cases. Five of the seven were true-negative specimen radiographs, making the efficacy rate 98%. Film-screen specimen radiography of clinically occult, noncalcified lesions is a highly effective procedure for correctly identifying the presence of a mammographic abnormality.     

Noninvasive assessment of metabolism in wounded skin by 31P-NMR in vivo.

Phosphorus-31 nuclear magnetic resonance techniques using shallow penetrating coils have been used to noninvasively monitor severity and metabolic changes over time in skin wounds in rats. Ratios of phosphocreatine (PCr) to inorganic phosphate (Pi) indicate energy status in both thermal wounds and surgical flaps. In partial and full-thickness scald wounds, reductions in PCr/Pi ratios correlated with burn depth and improved over time postinjury, suggesting wound revascularization. No decrease in intracellular pH was noted in these wounds; the phosphate shifts may be primarily the result of tissue degradation followed by restoration of the microvasculature. Distal regions of caudally based dorsal 3 x 10 cm full-thickness skin flaps reveal progressively lower PCr/Pi ratios to 3-6 hours after elevation as well as drops in pH up to 0.5 units, presumably as a result of anaerobic glycolysis in these tissues. After 24 hours, the intracellular pH returned to normal (7.1-7.2) and the PCr/Pi ratios approached 70%-90% of the well-perfused proximal regions within 3-7 days. These results indicate the establishment of a microvasculature from the underlying bed as the distal regions survive as free grafts. The data demonstrate the potential usefulness of the technique in noninvasive measurement of the biochemical response to injury and wound healing in living organisms.     

Long-term changes in the magnetic resonance image after chemonucleolysis

Summary After treatment of a symptomatic herniated disc with chymopapain, 14 patients were re-examined by magnetic resonance imaging (MRI) at a mean follow-up of 72 months. Well-defined MRI findings before chemonucleolysis were compared with those after the procedure by an independent observer. Five MRI parameters were assessed. No significant change was noted in the signal intensity of the affected disc, the extent of osteochondrosis and endplate reaction of the affected segment. The height of the affected disc as well as the size of the disc herniation were reduced significantly. The loss of the height is seen as a direct result of chymopapain activity, whereas the alteration of the size of the herniation seems to depend on the natural history of a disc herniation and is probably not a simple result of the treatment.     

Patterns of abnormal motor cortex excitability in atypical parkinsonian syndromes.

OBJECTIVE: Multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal-ganglionic degeneration (CBGD) are all clinically characterized by an akinetic-rigid syndrome together with a variety of additional signs. We hypothesised that these atypical parkinsonian syndromes (APS) will show distinctive patterns in their motor output upon transcranial magnetic stimulation (TMS) due to their different underlying anatomico-functional deficits. METHODS: We performed single and paired-pulse TMS and assessed inhibitory and excitatory response parameters from the first dorsal interosseus muscles in 13 patients with MSA, 18 with PSP, 13 with CBGD, 15 patients with Parkinson's disease and 17 healthy subjects. RESULTS: PSP and MSA patients had significantly enlarged response amplitudes at rest, reduced intracortical inhibition (ICI) and prolonged ipsi- and contralateral silent periods, whereas CBGD patients showed significantly increased motor thresholds, smaller response amplitudes at rest, shortened contralateral silent period, reduced transcallosal inhibition and a reduced ICI. In 22% of APS patients ipsilateral motor responses occurred in upper limb muscles irrespective of the underlying disease. CONCLUSIONS: Our results indicate that motor cortex disinhibition is predominant in patients with PSP and MSA. In CBGD more severe neuronal cell loss in the motor cortex itself may lead to hypoexcitability of corticospinal and transcallosal pathways.     

Low-dose endotoxin in allergic asthmatics: effect on bronchial and inflammatory response to cat allergen

BACKGROUND: Endotoxin was proposed to increase the severity of asthma. Endotoxin levels greatly differ according to settings. In domestic environments, airborne concentrations may be dramatically low compared with levels reported in occupational settings. OBJECTIVE: Our first objective was therefore to assess the effect of inhalation of low-level lipopolysaccharide (LPS) on the immediate and late-phase asthmatic bronchial response. Our second objective was to evaluate the effect of exposure to LPS on the local and systemic inflammatory response. METHODS: Nineteen asthmatics sensitized to cat underwent on two separate occasions a bronchial challenge test to cat allergen (cat BCT) preceded randomly by a pre-exposure to either saline or LPS (2 microg). Methacholine challenge test was performed 24 h before exposure to LPS or saline. The Borg scale for dyspnoea and lung function were recorded before and after exposure to LPS or saline, and before and after cat BCT. Induced sputum and blood samples were collected before and after cat BCT, and analysed for cell counts and eosinophil cationic protein (ECP) levels. RESULTS: Inhalation of 2 microg LPS did not induce any changes in forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), FEF 25-75 and Borg scale of dyspnoea. It neither modified Fel d 1 PD20 (45.03 ng as compared with 87.03; P=0.42). As well, there was no significant difference in late-phase reaction. Pre-exposure to LPS did not influence eosinophil counts or ECP levels in blood and sputum. CONCLUSION: Our study demonstrated that pre-exposure to LPS at low levels, which may be encountered in domestic environment, had no significant effect on the immediate and late-phase bronchial response to cat allergen. It neither modified local and systemic eosinophilic inflammation.     

Early and mid–term results of the Shelhigh stentless bioprosthesis in patients with active infective endocarditis

Summary Aims This study investigated the early and mid–term results following valve replacement with the new Shelhigh^? stentless bioprosthesis made entirely of biological material in patients with active infective endocarditis (AIE). Material and methods Between 02/2000 and 12/2004, 164 patients (n = 122 men, mean age 59, 18–85 years) received implantation of an AIE Shelhigh^? stentless bioprosthesis in the aortic, mitral, tricuspid or pulmonary position. A total of 119 patients (72.6%) had native AIE and 45 (27.4%) prosthetic AIE. A large proportion of the patients reached the operating room in a condition of cardiac decompensation: 37 (22.6%) patients were intubated, 40 (24.4%) had protracted septic shock and 41 (25.0%) required intensive catecholamine treatment. Surgery was regarded as urgent in 94 patients (57.4%) and was performed as an emergency procedure in 70 (42.6%). The mean follow–up time is 1.5 ± 0.11 years (range, 5 months to 5.2 years). Echocardiographic follow–up examinations were performed early postoperatively and after 12 months. Results In terms of the operative indication, we found a highly significant difference in the survival rate between patients who were operated on urgently vs in an emergency. In patients who died within 30 days, the main cause of death was septic multiorgan failure (67.6%). Only three patients required reoperation due to reinfection of the Shelhigh^? bioprostheses; this represents a reinfection rate of 1.8% in relation to the whole cohort. The postoperative echocardiographic examinations showed the Shelhigh^? valves to have very good hemodynamics without relevant pressure gradients. Conclusion Our experience in the use of Shelhigh^? bioprostheses in patients with native and prosthetic endocarditis show the early and mid–term results, in particular the low reinfection rate and the good hemodynamics, to be comparable with the results achieved using homografts. Since these prostheses are readily available and their implantation straightforward, they are increasingly being used in patients with endocarditis. These promising results need to verified in the long term. This paper was presented at a lecture held at the 71^st annual meeting of the German Society for Cardiology, Mannheim, 31. March—2. April 2005. Disclosure Form: The following study discloses my relationship with any corporate sponsor that might relate in some way to the subject presented.     

Novel molecular aspects of prostate carcinogenesis.

Prostate adenocarcinoma is one of the most frequently diagnosed forms of cancer in the male population of the Western world. The pivotal role of androgen and its receptor in this disease has been abundantly documented and indeed, chemical castration and treatment with antiandrogens are now standard therapies. However, relapse is often observed after 18-24 months, due to the remarkable ability of prostate tumour cells to adapt to low or undetectable androgen levels. Amplification and mutations of the androgen receptor (AR) gene have been described as well as alterations in cofactor expression and crosstalk with other signalling pathways. Another recent line of research focused on the re-programming of gene expression taking place in prostate tumours. Global expression profiling of normal and cancerous prostate tissues led to the identification of tumour-distinctive patterns. Validation studies are currently underway to identify novel drug targets as well as diagnostic and outcome prediction markers.     

Rat Cytomegalovirus-Accelerated Transplant Vascular Sclerosis Is Reduced with Mutation of the Chemokine-Receptor R33

Cytomegalovirus (CMV) infection accelerates transplant vascular sclerosis (TVS) and chronic rejection (CR) in both human and animal solid organ transplantation models. The host/viral mechanisms involved in this process are unclear. We examine the role of the rat CMV (RCMV)-encoded chemokine-receptor R33 in the development of TVS using a rat heart transplantation/CR model. F344 heart grafts were transplanted heterotopically into Lewis recipients. The ability of RCMV lacking the R33 gene (RCMV-Deltar33) to accelerate CR/TVS (neointimal index, NI) was compared to wild-type (WT) RCMV. Allograft recipients were infected with 1 x 10(5) pfu RCMV or RCMV-Deltar33 on postoperative day (POD) 1. Grafts from RCMV-Deltar33-infected recipients demonstrated an accelerated time to allograft CR compared to grafts from uninfected recipients (POD = 56 vs. 90), this was slower than that seen in grafts from WT-RCMV-infected recipients (POD = 45). Similarly, the degree of graft TVS formation at terminal rejection in RMCV-Deltar33 infected recipients was more severe than uninfected recipients (NI = 63 vs. 45), yet not as severe as in WT-RCMV infected recipients (NI = 83). In parallel, RCMV-Deltar33 failed to induce vascular smooth muscle cell (SMC) migration in vitro, whereas WT-RCMV induced substantial migration. The RCMV-encoded chemokine-receptor r33 is critical for RCMV-accelerated TVS/CR and vascular SMC migration.