Functional Assessment of Rabbit Alveolar Macrophages following Intermittent Inhalation Exposures to Sulfuric Acid Mist

Functional Assessment of Rabbit Alveolar Macrophages followingIntermittent Inhalation Exposures to Sulfuric Acid Mist. SCHLESINGER,R. B. (1987). Fundam. Appl. Toxicol. 8, 328–334. Sulfuricacid (H₂SO₄) aerosols are common in both ambient and occupationalenvironments. This study examined the numbers and selected invitro functional properties of alveolar macrophages recoveredfrom rabbits undergoing inhalation exposure to 0.5 mg/m³ submicrometer(0.3 µm) H₂SO₄ for 2 hr/day. Bronchoalveolar lavage wasperformed on Days 3, 7, and 14 during the exposure period (specifically,24 hr after either 2, 6, or 13 exposures). Total cell numbersand macrophage counts were increased on Day 3, but returnedto control levels by Day 7; no change in polymorphonuclear leukocyteswas observed at any time point. Macrophage substrate attachmentwas not affected by exposures to H₂SO₄, but random mobilitywas severely depressed at Days 7 and 14. The numbers of phagocyticallyactive macrophages and the level of such activity were increasedon Day 3, but became depressed by Day 14. These results demonstratesignificant alterations in important functional properties ofalveolar macrophages due to short-term intermittent exposuresto H₂SO₄ aerosols; these changes have implications for the abilityof the lungs to maintain adequate defense against depositedviable and nonviable particles.     

Solid phase peptide synthesis utilizing 9-fluorenylmethoxycarbonyl amino acids

9-Fluorenylmethoxycarbonyl (Fmoc) amino acids were first used for solid phase peptide synthesis a little more than a decade ago. Since that time, Fmoc solid phase peptide synthesis methodology has been greatly enhanced by the introduction of a variety of solid supports, linkages, and side chain protecting groups, as well as by increased understanding of solvation conditions. These advances have led to many impressive syntheses, such as those of biologically active and isotopically labeled peptides and small proteins. The great variety of conditions under which Fmoc solid phase peptide synthesis may be carried out represents a truly “orthogonal” scheme, and thus offers many unique opportunities for bioorganic chemistry.     

Phenytoin in the Treatment of Inducible Ventricular Tachycardia: Results of Electrophysiologic Testing and Long-Term FoUow-Up

Phenytoin treatment of inducible ventricular tachyarrhythmias was assessed by serial electrophysiologic studies (EPS) in 64 patients with spontaneous ventricular tachycardia, cardiac arrest, or symptoms compatible with a ventricular tachyarrhythmia. Coronary artery disease was the primary cardiac disease in 75% of the patients. All subjects had either inducible ventricular tachycardia (greater than or equal to 10 repetitive beats) or ventricular fibrillation at electrophysiologic study. Phenytoin was administered intravenously in 38 studies and orally in 31 studies. The mean serum phenytoin level was 19.5 +/- 4.7 mcg/ml. Only seven patients (11%) had a negative electrophysiologic study (less than or equal to 10 repetitive beats) after the administration of phenytoin and were classified as phenytoin responders (group I). The remaining 54 patients (89%) were classified as nonresponders (group II). For the nonresponders, phenytoin increased the cycle length of identical monomorphic ventricular tachycardias from a mean of 31 ms to a mean of 327 ms (p less than 0.001). For the four patients tested receiving both intravenous and oral phenytoin, the intravenous response always predicted the oral response. For the seven patients in whom electrophysiologic study indicated phenytoin efficacy, two are alive and arrhythmia-event free, two had sudden death when the regimen was changed (one case, quinidine added; one case, subtherapeutic serum level), and three died from nonarrhythmic causes. For the 10 patients treated empirically with phenytoin, either alone (seven patients) or in combination with another antiarrhythmic agent (three patients), four died secondary to an arrhythmic event.(ABSTRACT TRUNCATED AT 250 WORDS)     

Late Retesting of System Performance in ICD Patients Without Spontaneous Shocks

One hundred five implantable cardioverter defibrillator (ICD) patients (71 ± 9 years of age, 83% men) without spontaneous ICD discharges for ≥ 12 months were tested to assess high voltage (HV) circuit integrity and the system's ability to recognize and terminate ventricular fibrillation (VF). Indications for ICD implantation were sustained ventricular tachycardia (VT) (35%), cardiac arrest (27%), and inducible VT (38%). Eighty-two percent of the patients had coronary artery disease (CAD), and the mean left ventricular ejection fraction (LVEF) was 36%± 13%. Results: One hundred patients had inducible VF and five did not. Testing led to ICD reprogramming in 50 (49%) patients. Two (1.9%) patients required ICD replacement: (1) a 45-year-old patient with a Ventritex 110 ICD implanted for 13 months interfaced with a CPI 0062 lead implanted for 46 months could not be defibrillated internally (impedance nonmeasurable); (2) an 82-year-old patient with a 23-month-old Medtronic 7219 ICD interfaced with 6936 and 6933 leads whose defibrillation threshold (DFT) had doubled since implantation (24 J from 12 J). Lead fractures were found in both cases (proximal coil of the 0062, and subcutaneously in the 6933). Based on DFT determinations, the first shock output was programmed lower in 37 patients and higher in 10 patients. Shock pulse width was changed in one patient and the ventricular refractory period in another. No programming changes were made in 54 (51%) patients. Conclusions: (1) Late testing of HV circuit integrity in ICD patients without an ICD shock in ≥ 12 months identifies previously unsuspected HV lead fractures; (2) chronic DFT testing resulted in HV output reprogramming in one-half of the patients.     

STUDIES ON THE PHYSIOLOGY OF THE WHITE BLOOD CELL: THE GLYCOGEN CONTENT OF LEUKOCYTES IN LEUKEMIA AND POLYCYTHEMIA

The technic of determining glycogen in isolated white blood cells was appliedto the study of the different types of leukemia and of polycythemia, in order toobtain information on the physiology of the white blood cell. From this study itis concluded that the granulated leukocyte is the only carrier of glycogen in wholeblood. The "reducing substances" in lymphocytes and blast cells are not consideredas true glycogen.

The glycogen content of wet white blood cells in the rabbit amounts to about1 per cent. In the human being a range of from 0.17 to 0.67 per cent was calculated.In disease higher percentages occur, in polycythemia up to 1.64 per cent and inglycogen storage disease up to 3.05 per cent.

The glycogen concentration of normal white blood cells is within the same rangeas that of the striated muscle.

Note: I acknowledge with gratitude my indebtedness to Dr. William Dameshek for giving me the opportunity of analyzing the blood of some of the patients studied. Miss M. H. Campbell, Miss H. A. Clark,and Miss L. M. Garofalo have aided in carrying out many of the blood counts.

     

Reliability of Coated Wire Defibrillation Leads

A higher rate of complications and need for reoperation has been identified with epicardial and endocardial defibrillator systems. Improved reliability may be achieved with alternate designs that use coated wire and coated coil conductors. Six-year reliability in the 98% range is reported for one bipolar design, the Sulzer Intermedics Intervene® lead.     

The essential drugs programme in Zimbabwe: new approaches to training

The Zimbabwe Essential Drugs Action Programme has developedan innovative approach to training within the overall programme.The programme depends on the active participation of rural healthstaff in the production of training materials, combined withdesk-top publishing technology. The modules thus produced havebeen used at provincial and district workshops. Such an approachto the production of training materials is applicable to subjectsother than essential drugs.