Expression of the Plasmodium berghei ookinete protein Pbs21 in a baculovirus-insect cell system produces an efficient transmission blocking immunogen

A surface protein of Plasmodium berghei ookinetes, Pbs21, was expressed in a baculovirus-insect cell system in cell culture and in Heliothis virescens larvae. Groups of BALB/c mice received two intraperitoneal inoculations of either i) Tris-buffer or homogenized H. virescens larvae infected with wild-type baculovirus; ii) enriched, homogenized ookinetes, or Hi) homogenizedH. virescens larvae expressing recombinant Pbs21 (rPbs21). All animals immunized with ookinetes or with rPbs21 had high litres of antibodies (IgG isotype) that bound to native Pbs21. The large majority of antibodies in immune sera of both groups recognized the antigen under non-reducing but not under reducing conditions. The predominant IgG-sub-classes in mice immunized with ookinetes was IgGl and in mice immunized with rPbs21, the subclasses were IgGl and IgG2a. Immunization with rPbs21 reduced the infec-tivity of P. berghei to mosquitoes by 91% compared to a 99% reduction following immunization with ookinetes. This preliminary data indicate that rPbs21 expressed in this eukaryotic system induces a transmission-blocking immunity which is more effective than that achieved using rPbsll expressed in Escherichia coli (Matsuoka et al. 1994).     

Patient anxiety in the accident and emergency department

• ? Structured interviews were carried out with a sample of 96 patients to identify the sources of anxiety for patients in the accident and emergency (A & E) department.
• ? Only two patients reported that they were not at all anxious about any aspect of being in A & E. The average number of anxieties reported was 69.
• ? The most frequently reported anxieties were ‘not being able to carry on your usual activities’, ‘not knowing what will happen to you in the department’, ‘having to undergo an uncomfortable procedure’, ‘feeling pain’ and ‘not knowing what is wrong’.
• ? The findings indicate that patients were as concerned with psychological and social aspects associated with admission as they were about psysical factors.
• ? The authors suggest that it is essential for nurses in A & E to assess patients holistically and consider their psychological state and social circumstances as well as their physical condition. There is also a need for closer links to be developed between accident and emergency departments and other community health agencies and for more emphasis to be placed on referral to other bodies.

     

Clinical Experience with a New Multiprogrammable Dual Chamber Pacemaker

We evaluated the clinical performance of a new dual chamber pacemaker, ELA Chorus(tm), in 35 patients. This device incorporates linear rate adaptive AV delay (AVDR), rate smoothing, fallback, impedance telemetry, pacemaker mediated tachycardia (PMT) recognition and reprogramming software, intracardiac electrogram displays, aufothreshold testing, diagnostic data, battery depletion curves, and laptop computer programming. Mean patient age was 68 years; 18 patients had AV block, six had sinus node dysfunction (one with AV block), nine had carotid sinus hypersensitivity (three with AV block), and two had vagally mediated syncope. At hospital discharge, programming was DDD with a mean low rate of 60 (50–70) beats/min, mean high rate of 126 (120–154) beats/mm; AVDR was ON in 21 patients, rate smoothing ON in six patients, fallback ON in six patients, and PMT reprogramming algorithm ON in 27 patients, Pacemaker follow-up involved 500 clinic visits over 14.3 months (1–36). Three patients developed atrial fibrillation, reprogrammed to DDI mode (two patients) or fallback (one patient). Fallback was used 617 times. PMT occurred 427 times in six patients; the PMT algorithm reprogrammed AV delay and postventricular atrial refractory period (PVARPJ automatically, a function unique to the Chorus(tm). Intracardiac electrograms and autothreshold testing improved follow-up efficiency. This new dual chamber pacemaker enhances programming flexibility and improves diagnostic accuracy at follow-up.     

Analysis of the Effectiveness of In-Office and Transtelephonic Follow-Up in Terms of Pacemaker System Complications

A study was undertaken to determine the most effective method of pacemaker follow-up in terms of the total number of complications detected and yield per follow-up in single and dual chamber pacing systems. The analysis involved 9,786 patient records from 635 patients. The records were reviewed with respect to method of follow-up, number of chambers paced, and complications detected. Complications included: oversensing, undersensing, noncapture, pocket and diaphragmatic stimulation, pacemaker mediated tachycardia, crosstalk, pulse generator malfunction, lead malfunction, infection/erosion, premature end of service, exit block, and other miscellaneous problems. Eight thousand two hundred eighty-eight of the 9,786 follow-ups were performed in the office while 1,498 were transtelephonic. Single chamber pacing systems were implanted in 329 patients and 306 were dual chamber systems. A total of 599 complications were detected. Analysis yielded a per patient complication rate of 5.1 % (single chamber) and 8.4% (dual chamber) for in-office follow-up. This compared to a transtelephonic follow-up per patient complication rate of only 0.3% (single chamber) and 1.0% (dual chamber). In-office pacemaker follow-up is significantly more effective (P < 0.001) than transtelephonic follow-up in detecting both single and dual chamber pacemaker system complications.     

Encainide for the Treatment of Refractory Ventricular Tachycardia in Patients Undergoing Programmed Electrical Stimulation

Encainide was evaluated in 26 patients undergoing programmed electrical stimulation (PES) for ventricular arrhythmias. These patients had inducible symptomatic ventricular tachyarrhythmias during baseline PES and had previously failed a mean of 3.2 antiarrhythmic agents. Encainide was discontinued in six patients prior to PES because of spontaneous ventricular tachycardia (VT) (five patients) and adverse effect (one patient). Encainide increased, the PR, QRS, QTc intervals, and right ventricular effective refractory period (RVERP) significantly from baseline (P < 0.05) in 16 patients who were extensive metabolizers. Encainide, at a mean dose of 110 ± 28 mg/day increased the ventricular tachycardia cycle length (VTCL) from 278 ± 77.1 msec to 334 ± 68.8 msec (P < 0.05). Encainide alone was effective (< 15 beats induced) or partially effective (converting inducible sustained VT to < 15 beats asymptomatic nonsustained VT or increasing the VTCL < 100 msec with no symptoms) in two and seven patients respectively. In seven patients, encainide was also reevaluated at a higher dose (mean dose 148 ± 22 mg/day), but this dose did not significantly alter the overall response or measured parameters. Seven patients were subsequently evaluated on combination of encainide and another antiarrhythmic agent. The combination was effective in three patients and partially effective in three patients. Serum concentrations were measured during each testing period; a moderate correlation was observed between the PR and RR intervals and total concentrations in patients who were extensive metabolizers. Eleven patients who were effective or partially effective during acute testing were placed on long-term encainide therapy (three patients alone and eight patients on combination therapy). In a mean follow-up of 8.9 months (1–25 months) encainide was discontinued in five patients (two patients due to nonsudden cardiac death, one patient due to recurrent nonfatal VT, and two patients due to side effects of combination therapy.) Conclusion: Encainide alone is minimally effective (7.7%) for preventing inducible ventricular tachycardia, but partially effective in 38.9%. Retesting at a higher dose does not offer any additional benefit. However, encainide in combination with another antiarrhythmic agent may improve the response in patients who remain inducible on encainide alone. Further studies are needed to verify this observation.     

Fibronectin in synovial fluid and tissue in rheumatoid arthritis

Fibronectin is a glycoprotein found in body fluids, loose connective tissue matrix and in basement membranes. Fibronectin in rheumatoid arthritis synovial fluid was immunologically indistinguishable from the plasma form, as shown by double-diffusion analysis. Fibronectin isolated from rheumatoid synovial fluid by affinity chromatography on gelatin--Sepharose had a polypeptide pattern similar to that of plasma fibronectin in SDS--polyacrylamide gel electrophoresis. In fifty-one patients with rheumatoid arthritis and related diseases fibronectin concentrations is synovial fluid were 445 +/- 103 micrograms/ml (mean +/- SD) and within normal range, 335 +/- 52 micrograms/ml, in plasma. Immunofluorescence staining showed a prominent increase of fibronectin in the proliferating synovial connective tissue in rheumatoid arthritis as compared to normal synovial membrane. The results suggest an increased local production of fibronectin in rheumatoid synovial tissue.     

A marvellous and authentic account: the first written report of haemophilia in America

Summary. The first written record of haemophilia in America is reputed to be the 1791 newspaper obituary of Isaac Zoll. The earlier, original publication of this obituary is identified.