Application of contact laser scalpel in thoracic surgery

The authors have carried out 296 transthoracic and endoscopic YAG-laser operations in various diseases of bronchopulmonary system. Sapphire and quartz applicator-tips were used as a contact scalpel. The procedures of laser operations with the use of the contact mode are described in detail and comparative evaluation of both types of thermal applicator-tips is given. The combination of cutting and coagulation properties of the contact laser scalpel enables its use in various operations on the lung and pleura including thoracoplastic interventions as well as accomplishment of an endoscopic photoresection of endobronchial tumors.     

Structural requirements for the cytotoxicity of the N-terminal region of HIV type 1 Nef

We have found that the hemolytic and cytotoxic activities of myristoylated Nef N-terminal peptides require a net positive charge in the first seven amino residues of the sequence. The activities are considerably less dependent on the secondary structure of the peptides. Film balance studies showed that both active and inactive peptides interacted with neutral phospholipid monolayers, suggesting that binding to neutral lipids was not a sufficient condition for lytic activity. It was also found that nonmyristoylated N-terminal peptide did not interact to the same extent with the monolayer, indicating that myristoylation was essential for lipid interaction. It is considered that the positively charged residues of the proximate N terminus of Nef interact with acidic lipids of biological membranes, reinforcing the weak membrane-targeting properties of the myristyl chain. Parallels are drawn between this mode of interaction with membranes and that of members of the Src family of proteins, which are also myristoylated and have positively charged residues in their proximate N termini. In particular, these proteins and Nef also have serine residues in their proximal N-terminal regions, which when phosphorylated could neutralize the positive charge and thus provide a mechanism for modulating membrane interaction.     

Telemedicine in Australia. Recent developments

To assess the frequency and natural history of swallowing problems following an acute stroke, 121 consecutive patients admitted within 24 hours of the onset of their stroke were studied prospectively. The ability to swallow was assessed repeatedly by a physician, a speech and language therapist, and by videofluoroscopy. Clinically 51% (61/121) of patients were assessed as being at risk of aspiration on admission. Many swallowing problems resolved over the first 7 days, through 28/110 (27%) were still considered at risk by the physician. Over a 6-month period, most problems had resolved, but some patients had persistent difficulties (6, 8%), and a few (2, 3% at 6 months) had developed swallowing problems. Ninety-five patients underwent videofluoroscopic examination within a median time of 2 days; 21 (22%) were aspirating. At 1 month a repeat examination showed that 12 (15%) were aspirating. Only 4 of these were persistent; the remaining 8 had not been previously identified. This study has confirmed that swallowing problems following acute stroke are common, and it has been documented that the dysphagia may persist, recur in some patients, or develop in others later in the history of their stroke.     

Modification of lethal radiation injury in mice by postradiation exposure to low-intensity centimeter-band radio frequency waves

A clearly pronounced modification of acute radiation injury of mice has been obtained by prolonged action (for up to 23 hours) of low-intensity (5 +/- 1.5 mu Wt/cm2) radiofrequency radiation in the ranges of 2-8, 8-18 and 19-27 GHz with a swing frequency of 12-14 Hz, applied immediately after exposure to lethal dose of gamma-radiation. Survival of mice and average life duration of killed mice were increased.     

Pharmacokinetics of a high dose of gentamicin administered intravenously or intramuscularly to horses

PURPOSE: The effect of uridine (UR) coadministration on the intestinal metabolism from 5'-deoxy-5-fluorouridine (5'-DFUR) to 5-fluorouracil (5-FU) was evaluated by a method of concentration difference between portal and systemic bloods in conscious rats (PS method). METHODS: 5'-DFUR (100 mg/kg) alone (Group A), or 5'-DFUR + UR (100 mg/kg each) (Group B) was orally administered to conscious rats. The portal and arterial bloods were simultaneously withdrawn from two canulas at appropriate time intervals, and blood concentrations of 5'-DFUR, 5-FU, UR and uracil (U) were assayed by HPLC. The concentration-time profiles of these drugs and its metabolites were analyzed by local moment analysis. RESULTS: UR coadministration made the local absorption ratio (Fa) of 5'-DFUR decrease significantly from 60.1 +/- 10.5% to 38.0 +/- 18.6% of dose. Though the local absorption ratios (Fm(a)) of the metabolite (5-FU) were the same between Group A and Group B (8.3 +/- 1.9 and 8.7 +/- 4.0% of 5'-DFUR, respectively), AUC of arterial 5-FU in Group B was 5 times greater than that in Group A. UR was not detected in the portal blood, and Fm(a) of U was estimated to be 41.9 +/- 26.8% of UR in Group B. CONCLUSIONS: It is predicted that a large portion of 5-FU generated from 5'-DFUR is further degraded in the intestine in Group A, and U generated from UR blocks 5-FU degradation in the intestine and the systemic circulation in Group B.     

Calmodulin-stimulated cyclic nucleotide phosphodiesterase (PDE1C) is induced in human arterial smooth muscle cells of the synthetic, proliferative phenotype

The diversity among cyclic nucleotide phosphodiesterases provides multiple mechanisms for regulation of cAMP and cGMP in the cardiovascular system. Here we report that a calmodulin-stimulated phosphodiesterase (PDE1C) is highly expressed in proliferating human arterial smooth muscle cells (SMCs) in primary culture, but not in the quiescent SMCs of intact human aorta. High levels of PDE1C were found in primary cultures of SMCs derived from explants of human newborn and adult aortas, and in SMCs cultured from severe atherosclerotic lesions. PDE1C was the major cAMP hydrolytic activity in these SMCs. PDE expression patterns in primary SMC cultures from monkey and rat aortas were different from those from human cells. In monkey, high expression of PDE1B was found, whereas PDE1C was not detected. In rat SMCs, PDE1A was the only detectable calmodulin-stimulated PDE. These findings suggest that many of the commonly used animal species may not provide good models for studying the roles of PDEs in proliferation of human SMCs. More importantly, the observation that PDE1C is induced only in proliferating SMCs suggests that it may be both an indicator of proliferation and a possible target for treatment of atherosclerosis or restenosis after angioplasty, conditions in which proliferation of arterial SMCs is negatively modulated by cyclic nucleotides.     

Application of plasma scalpel for cholecystectomy

107 male patients with diabetes mellitus type II (DM) combined with hypertension aged 62 to 76 years were divided into 5 groups comparable by DM but different by characteristics of hypertension, ischemic heart disease or other associated diseases the presence of which determined the choice of one or another drugs against hypertension. These drugs belonging to 5 groups (calcium antagonists, inhibitors of angiotensin converting enzymes, beta-blockers, alpha-blockers, agonists of imidasoline receptors) were compared in monotherapy and combined therapy for hypotensive activity and safety. It was found that monotherapy with corinfar, capoten, and cint had a potent hypotensive effect, atenolol and prasosin had moderate hypotensive efficacy and caused side effects more frequently. In differentiated use of the above drugs negative effects on associated diseases did not occur.     

Potassium channels in epithelial cells

The broad array of K- channels in epithelial cells includes voltage-dependent (mainly outward) and Ca(2+)-activated channels, and K+ channels modulated by adenosine triphosphate (ATP). Voltage-dependent K+ channels mediate Na+/K+ absorption and secretion; typically, they are found in the basolateral membrane and exhibit burst activity. Ca(2+)-activated K+ (Ca2+/K+) channels regulate activity by decreasing Ca2+ influx via voltage-gated Ca2+ channels. Ca2+/K+ channels exhibit conductances of 4-300 pS, and have a low open probability (< 10(-7)) at the level of the resting membrane potential. ATP-sensitive channels have been observed mainly in insulin-secreting pancreatic beta-cells and in the urinary tract, where the open state is rapidly closed by ATP. The channels are voltage-dependent, exhibit burst activity, and, in the case of the urinary-tract cells, are Ca2+ dependent. Chemical compounds that selectively open or block K+ channels have been exploited to characterize channels found in different cells, but no opener or blocker has been found that specifically affects only one type of K+ channel. Specialized model systems and recombinant techniques have led to a general understanding of the structure of K+ channels, but many important details remain to be determined.