Dubowitz syndrome with keloidal lesions

The case of a 7-year-old boy affected by Dubowitz syndrome is described. The characteristic features of the syndrome—intrauterine growth retardation, low neonatal weight, short stature, characteristic facies, atopic dermatitis and mental retardation—are discussed with reference to the absence of microcephaly and the presence of spontaneous keloids.     

Overdrive and Programmed Atrial Electrostimulation in the Study of the Electrogenetic Mechanism of Atrial Flutter in Man

The response of atrial flutter (AF) to programmed atrial stimulation (PAS) (13 cases) and overdrive atrial pacing (OAP) ws studied in a total of 18 patients. During PAS the return cycle was equal to the basic cycle of AF in six patients, shorter in one patient, and slightly longer in six; it was never compensatory. ATrial flutter terminated in two patients by PAS and by OAP in three. In 4 patients, PAS resulted in an acceleration of the AF rate, followed by spontaneous interruption within 2 seconds. In the remaining patients, the stimulation either converted the AF into an uncommon type of AF (two patients) or into atrial fibrillation that was followed by spontaneous return to sinus rhythm. In two patients it was possible to reproduce the AF with PAS; in one of the patients another type of AF was induced. Some of the data observed suggest a re-entry circuit as the electrogenetic mechanism responsible for AF in man.     

Epidural Spinal Electrostimulatory System (ESES) in the Management of Diabetic Foot and Peripheral Arteriopathies

Epidural spinal electrostimulatory system (ESES) or dorsal column stimulation (DCS) may be used for the treatment of peripheral vascular diseases of the lower extremities. ESES has been used in our metabolic and surgical department as a way to ameliorate inadequate blood supply in patients suffering from diabetic foot (seven patients), painful chronic arterial narrowing, or inoperable occlusions (25 patients). The continuous stimulation by an implantable apparatus (Medtronic model Itrel, Medtronic, Inc., Minneapolis, MN, USA) led to a reduction or disappearance of pain, an improvement in plethysmographic curves, functional performance, and trophic lesions in about 75% of the patients. The system is safe and well-tolerated by patients.     

THERMOLYSIN AND BACILLUS SUBTILIS NEUTRAL PROTEASE

A comparative study on thermolysin from Bacillus thermoproteolyticus and neutral protease from Bacillus subtilis involving far-and near-ultraviolet circular dichroism (CD) and immunological techniques is reported. These enzymes are homologous metalloendopeptidases, having similar size, kinetic behaviour, substrate specificity and susceptibility to inhibitors. The far-ultraviolet CD spectrum of each protein shows a minimum at 208 and a shoulder near 220 nm; differences in the extent of ellipticity, however, have been observed. Estimates of secondary structure obtained by quantitation of the far-ultraviolet CD spectra indicated a higher helicity of neutral protease relative to thermolysin. In the presence of ethylenediaminetetraacetic acid, which removes calcium and the functional zinc ion from the metalloenzymes, neutral protease is immediately denatured, whereas thermolysin maintains a globular structure, although thermolabile. On the other hand, the zinc-specific chelating agent tetraethylenepentamine does not have measurable effects on the conformation and conformational stability of either protein. Marked higher stability to temperature and guanidine hydrochloride were observed for thermolysin as compared with neutral protease, as indicated by monitoring conformational transitions with CD measurements at 220 nm. Antisera prepared in rabbits using thermolysin as immunogen do not cross-react with neutral protease, indicating differences of surface structure between the two proteins. On the basis and limitations of the techniques employed, it is proposed that the two sequentially and functionally homologous metalloendopeptidases may have similar conformations at specific regions (active and binding sites, at least) of the polypeptide chain essential for biological function, while some variability in the structure of other regions may be tolerated.