Radioisotopic Pacemaker: Long-Term Clinical Results

In order to prolong the service life of the generator, the isotopic pacemakers, powered by Pu²³⁸, have been developed and implanted since 1970. We report the follow-up of 325 patients (mean age 39 ± 18 years) implanted with an isotopic pulse generator (Medtronic 9000/9090) between April 1970 and July 1982. The mean follow-up was 12 years (range 6 days to 18.5 years). The generator was highly reliable; the mean value of pacing rate between implantation and last follow-up decreased significantly but no more than 1 beat/min (72.7 vs 71.8 beats/ min; P < 0.001) and the pulse width did not change significantly. The actuarial survival of the device was 97% at 18.5 years. During the follow-up period, 122 reoperations were performed in 85 patients: 88 explanations of the entire pacing system and 34 modifications of the lead system. Lead dysfunction accounted for 68% of the 122 reoperations, generator failure for 6%, and miscellaneous reasons for 26%. However, 72% of patients remain free of intervention during the follow-up period and 61 patients (20%) died during this period. Most deaths (52%) were of nonsudden cardiovascular origin, 17% were related to cancer, and 13% to sudden death. After 5, 10, and 18.5 years, 94%, 89%, and 73% of the patients were alive, respectively. No side effect could be attributed to the radioisotope. We conclude that this isotopic pacemaker demonstrated its reliability for long-term cardiac pacing.     

Intensive melphalan chemotherapy and cryopreserved autologous bone marrow transplantation for the treatment of refractory cancer

Thirty-three adult and pediatric patients with refractory malignancies were treated with escalating doses of melphalan (120-225 mg/m2 IV over 3 days) followed by reinfusion of previously harvested and cryopreserved autologous marrow. The hematological and nonhematological toxicities and the therapeutic effects of this regimen were evaluated. Increasing doses of melphalan did not alter the rate of decline nor the recovery of peripheral blood counts. Granulocyte (greater than 500/microL) and platelet count (greater than 20,000/microL) recovery occurred in a median of 19 (range 12-54) and 24 (range: 12-54) days after bone marrow transplantation, respectively. Five patients experienced severe infection, three of which were fatal, and one patient died due to thrombocytopenic hemorrhage. Toxicity to the gastrointestinal system was dose limiting. The maximum tolerated dose of melphalan was 180 mg/m2; only three of 24 patients experienced severe stomatitis, esophagitis, and diarrhea at this level or less, while eight of nine patients at 225 mg/m2 were affected (p less than 0.005). Administration of cyclophosphamide (300 mg/m2 IV) 1 week before melphalan therapy did not reduce the incidence of severe gastrointestinal toxicity. Plasma melphalan concentration peaked 30-60 min after infusion (4.8-11.5 micrograms/mL) but declined rapidly. Cerebrospinal fluid concentration was 10% of the corresponding plasma concentration and was undetectable at 3 hours. Antitumor responses occurred in nine of 13 patients with malignant melanoma (five complete and four partial remissions), and ranged 2-12+ months with a median of 5 months. Four of six neuroblastomas demonstrated responses (three complete and one partial remission( lasting a median of 7.5 (range: 5-10) months. Other tumors in which this regimen had activity included breast cancer and Ewing's sarcoma. The overall response rate for the 33 patients was 30% complete remissions (10 patients) and 21% partial remissions (seven patients). High dose melphalan and autologous bone marrow transplantation is a promising therapy for patients with malignancies for which no effective treatment is known or for patients whose cancer is refractory to conventional therapeutic agents.     

Presence of leucocyte inclusions in spleen and bone marrow of patients with Felty's syndrome.

The spleens from two patients with Felty's syndrome and the bone marrow from one patient with Felty's syndrome were examined for the presence of intracytoplasmic inclusions in neutrophils when stained with antibodies to IgG, IgM, IgA, and betalc. Four normal spleens from trauma patients were similarly examined. In both spleens and the bone marrow from the Felty patients, large inclusions were noted. In none of the four normal spleens were large inclusions present. These studies suggest that phagocytosis of immune complexes by neutrophils in Felty patients may induce sequestration of these cells in the spleen and bone marrow.     

The distribution of blood group antigens and alloantibodies among Chinese in Taiwan

Most blood group antigens among Chinese people are very homogeneous (e.g., D, 99.4%; K, 0%; Fya, 99.7%). The frequency of clinically significant alloantibodies detected by the authors' crossmatching was only 0.146 percent, suggesting that pretransfusion testing can be greatly simplified in Chinese populations.