Autopsy Case Report of Severe COVID-19 Pneumonia at a General Municipal Hospital.

We present the autopsy procedure and findings of severe coronavirus disease 2019 (COVID-19) pneumonia in an 85-year-old man. The patient required intubation immediately after admission for severe COVID-19 pneumonia. He had severe hypoxia that did not improve despite treatment with remdesivir, corticosteroids, and appropriate mechanical ventilation. On day 13, the patient developed sudden hypercapnia. His renal dysfunction subsequently worsened and became associated with hyperkalemia, and he passed away on day 15. An autopsy was performed to clarify the cause of the hypercapnic hypoxia. None of the medical personnel involved in the autopsy developed symptoms of COVID-19. Histologic examination showed various stages of diffuse alveolar damage throughout the lungs, with intra-alveolar hemorrhage in the upper zones. Microscopic examination of the kidneys revealed acute tubular necrosis. There was no significant systemic thrombosis. The autopsy findings were consistent with those typical of COVID-19.

Long-term follow-up of busulfan, etoposide, and nimustine hydrochloride (ACNU) or melphalan as conditioning regimens for childhood acute leukemia and lymphoma.

We retrospectively evaluated early and long-term complications of an intensified conditioning regimen consisting of busulfan and etoposide in combination with either nimustine hydrochloride (ACNU) (BVA regimen, n = 18) or melphalan (BVL regimen, n = 34) in 52 children with acute leukemia or non-Hodgkin's lymphoma. With a median follow-up of 13.2 years after the BVA regimen and 8.1 years after the BVL regimen, 61% and 76% of patients, respectively, are in continuous complete remission. Transplantation-related mortality was 17% and 6% after the BVA and BVL regimens, respectively, and the corresponding relapse rates were 17% and 15%. The most common and severe toxicity was pulmonary complication in the BVA regimen, which was seen in 67% of patients and was life-threatening in 20%. Thirty-three percent of patients after the BVA regimen and 24% after BVL died of relapse or disease progression (n = 9), interstitial pneumonia (n = 2), fungal pneumonia (n = 1), or chronic graft-versus-host disease (n = 2). One of the long-term survivors developed secondary leukemia. A significant decrease in the height standard deviation score of more than 2 SD from diagnosis to the last follow-up was seen in 17% of the patients, with hypothyroidism in 15%, and alopecia in 42%. Because our experience is limited to a small heterogeneous population of patients who mainly underwent transplantation in the first remission, we cannot draw conclusions on the treatment's effectiveness. The BVL regimen is tolerable, however, because no regimen-related death was observed, whereas the BVA regimen is not recommended because of the high incidence of pulmonary complications. The effectiveness of the BVL regimen requires further study.

Serial transplantation of p53-deficient hemopoietic progenitor cells to assess their infinite growth potential.

Thirty-five years ago, Siminovitch et al. (Siminovitch L, Till JE, McCulloch EA. J Cell Com Physiol 64:23-32, 1964), using serially transplanted mouse spleens at 14-day intervals, observed a markedly progressive decline in the proliferative capacity of bone marrow (BM) cells, with the loss of clonogenicity by the fourth transplant generation. Using the same protocol, we assessed the proliferative capacity of p53-deficient mouse BM cells transplanted serially at the same 14-day intervals into lethally irradiated mice, which was a useful tool for understanding the characteristics of hemopoietic stem cells lacking solely the p53 gene function. BM cells from p53-deficient homozygous (p53(-/-)), p53-heterozygous (p53(+/-)), and wild-type (p53(+/+)) C57BL/6 mice were transplanted into lethally irradiated C57BL/6 recipients. Fourteen days later, the repopulated spleens were harvested, and 10(7)cells were retransplanted into secondary recipients. Serial transplantation was continued at 14-day intervals until hemopoietic repopulation failure. The number of heterozygous and homozygous p53-deficient spleen cells increased logarithmically up to the fourth and fifth passages, respectively, whereas wild-type spleen cells ceased to proliferate by the third passage. The number of macroscopic spleen colonies increased logarithmically until the third passage in recipients of heterozygous and homozygous p53-deficient cells, but ceased to grow by the second passage in recipients of wild-type cells. The numbers of heterozygous and homozygous p53-deficient colony forming units in spleen (CFUs-S) remained stable during the first four transplant generations, whereas that of wild-type CFUs-S decreased progressively from the first transplant generation onward. The clonogenicity of p53-deficient cells was lost when the number of CFUs-S per spleen decreased to below 10. This suggests that one out of 10 CFUs-S might be long-term repopulating cells (LTRCs), and that p53-deficient LTRCs may proliferate more rapidly than wild-type LTRCs. Longer passages that were possible in the p53-deficient groups were considered to be due to the faster cell cycle of the p53-deficient hemopoietic progenitor cells, as determined by bromodeoxyuridine incorporation with purging by UV light exposure, followed by hemopoietic colony assay (BUUV assay).