Solid-phase synthesis of neurokinin A antagonists

During the preparation of the NK-2 selective tachykinin antagonist MEN 10208 (Thr-Asp-Tyr-D-Trp-Val-D-Trp-D-Trp-Arg-NH₂) and its analogs by the solid-phase method employing the Boc strategy routinely used in our laboratory, we encountered difficulties in the coupling of hydrophobic amino acids D-Trp and Val. To study the coupling problems several syntheses of MEN 10208 and analogs were carried out with different activation strategies. These syntheses yielded considerable amounts of deletion sequences even though a negative Kaiser test was obtained after each coupling. Inaccessibility of the free amino group of the growing peptide due to steric hindrance of the hydrophobic residues during coupling, and for the ninhydrin complex during the Kaiser test, may account, at least in part, for the unsatisfactory synthetics results and for the false-negative ninhydrin tests. Repetition of each synthesis with the Fmoc strategy on a newly developed DOD resin for peptide amides using the DCC/HOBt chemistry gave superior results in terms of the yield and purity of the crude peptides. Therefore, the Fmoc strategy appears to offer advantages over the Boc method for the preparation of these peptides containing hydrophobic amino acids.     

Ventricular Cross Stimulation in a Dual Chamber Pacing System: Phenomenon Analysis

Seven cases of ventricular cross stimulation from a group of 23 patients implanted with DDD devices are presented. In two patients the phenomenon was observed at the moment of DDD programming at nominal values, and in five other patients it was reproduced by increasing the atrial output voltage up to ten volts. In all 23 patients cross stimulation disappeared permanently within 24 hours after implantation. From the onset of cross stimulation to its end, atrial and ventricular threshold voltages were unchanged, while the atrial and ventricular impedances significantly decreased. These results suggest that an important role in the phenomenon occurs by impedance variation at the interface between the pulse generator and body tissue.     

DENSITOMETRY OF PAUTRIER'S MICROABSCESS CELLS IN CUTANEOUS T CELL LYMPHOMA

Background. Epidermotropic lymphoid T cell infiltrates are part of a continuous spectrum of lesions ranging from “benign” parapsoriasis to frank cutaneous T cell lymphoma (CTCL, mycosis fungoides). Either the clinical or histologic differentiation between these entities prove often difficult and the prognosis may be difficult to assess. Patients and Methods. We studied 15 patients, men aged 50 to 81 years, mean ± SD 68 ± 12 years, with patch-plaque CTCL. Sections from punch biopsies from active lesions were stained with Feulgen reagent, coupled with a “twin” adjacent hematoxylin and eosin (H&E)-stained section and analyzed with a VIDAS Zeiss-Kontron Image Analyzer. At least 50 dermal infiltrating cells and 50 epidermotropic Pautrierian cells per specimen were counted and the biopsies were repeated periodically. Results. Nine patients with aneuploid Pautrierian cell DNA patterns did well after conventional phototherapy (dermal cell ploidy was irrelevant), whereas six patients with euploid Pautrierian cell DNA patterns had to be treated aggressively (IFN + retinoids, COP). Clinical and histopathologic aspects of the first group were comparable to those of the second group. Conclusions. The classical cytophotometric aphorism seems to be reversed in this sample: “The more abnormal the ploidy of epidermotropic Pautrierian cells, the better the prognosis.” Euploid epidermotropic cell prove more efficient in invading the skin and other areas and this efficiency may be reflected in more aggressive trends in the evolution of the lymphoma. Thus, DSM analysis of epidermotropic cells could prove very useful as an inexpensive tool for routine CTCL grading.     

Duplex-Doppler assessment of cirrhosis in patients with chronic compensated liver disease

Portal venous flow velocity (PFV) was measured with duplex-Doppler equipment in 50 normal subjects and in 117 patients with suspected chronic liver disease who showed no evidence of decompensation such as ascites, hepatic encephalopathy, jaundice or oesophageal bleeding. All the patients underwent percutaneous liver biopsy which demonstrated non-cirrhotic liver disease in 58 cases (CH-patients: steatosis 8, persistent chronic hepatitis 8, active chronic hepatitis 42) and liver cirrhosis in the other 59 cases (LC-patients). The normal subjects and the CH-patients had similar values of max-PFV and mean-PFV (max-PFV 26.7±3.2 and 25.7±3.4 cm/s respectively; mean-PFV 22.9±2.8 and 22.4±3.8 cm/s respectively). The LC-patients’ values (max-PFV 19.3±3.5; mean-PFV 16.9±2.9) were significantly lower than those of the normal subjects (P<0.001) and of the CH-patients (P<0.001). Considering the normal max-PFV to be in the range 20–33.1 cm/s (mean±2 s.d. of the normal subjects, 95% confidence limits), max-PFV was reduced in 0/50 normal subjects, 1/58 CH-patients and 39/59 LC-patients (66.1% sensitivity; 98.2% specificity). In conclusion, the duplex-Doppler measurement of PFV is of great interest in the diagnostic study of patients with suspected chronic compensated liver disease and in the early diagnosis of cirrhosis. A low max-PFV is a reliable pointer to liver cirrhosis, whereas a normal max-PFV indicates a non-cirrhotic liver disease but is less probative. Each centre should standardize normal PFV values in order to establish their own threshold value for diagnosing liver cirrhosis.