Histone phosphorylation and chromatin structure were examined in synchronized CHO Chinese hamster cells during progression through mitosis. Cell population distribution in various phases of mitosis was determined by electron microscopy. Entry into mitosis was seen to occur in two stages: (1) the gathering of chromatin into aggregates of dense chromatin clumps during preprophase, followed by (2) the condensation of these aggregates into chromosome structures during prophase. Exit from mitosis was observed essentially as the reverse process, chromosomes first being disorganized into dense chromatin clumps during telophase, followed by dispersion of these aggregates in early G1. Correlating these structural changes with histone phosphorylation revealed that interphase-type histone H1 phosphorylation (H1 I) involving 1 -3 phosphates per molecule existed in interphase and during the chromatin aggregation stages of mitosis (preprophase and telophase). Also, no histone H3 phosphorylation occurred during these periods of the cell cycle. It is proposed that HIl phosphorylation may be involved with the submicroscopic changes in chromatin organization observed during interphase using molecular probes of chromatin structure. However, during mitosis, histone phosphorylation was correlated with microscopic chromatin structural changes. During the second stage of mitosis (prophase, metaphase, and anaphase), when chromosome structures were fully condensed, virtually all histone H1 existed as superphosphorylated molecules (H 1M) containing 3-6 phosphates, and all histone H 3 molecules were phosphorylated. Exit of cells from anaphase correlated closely with the dephosphorylation of H3 to unphosphorylated H3 and with the dephosphorylation of H~M to subphosphorylated H1 containing 0-3 phosphates. Further dephosphorylation of subphosphorylated HI to unphosphorylated H1 occurred as these cells left telophase and entered G1. These experiments demonstrated that H1M superphosphorylation and H3 phosphorylation are strictly mitotic events which occur only when chromosomes are fully condensed. The absence of Colcemid in some of these experiments eliminates the possibility that H I M and H3 phosphorylations are artifacts of the Colcemid treatment. It is proposed that histones H1 and H3 may impose a restriction on chromatin structure which prevents chromosome condensation during interphase and that the HlM and H3 phosphorylations remove this restriction during mitosis.Many investigators have proposed that DNA activities might be controlled by modulating the structure of chromatin through reversible modifications of the histone proteins (for recent review see [l I). Experimental results from our laboratory have supported this concept by demonstrating that the modification of histones by phosphorylation is associated with changes in chromatin structure [2-101. The strongest evidence for a correlation between histone phosphorylation and chromatin structural change has been found at mitosis. For example, in synchronized cultured mammalian cells,...

A retrospective review of Mayo Clinic records through 1983 revealed 84 patients (24 male and 10 female; mean age, 41 years) with the diagnosis of pulmonary alveolar phospholipoproteinosis. The major clinical features were dyspnea, cough, fever, and chest pain. Chest roentgenograms usually showed bilateral symmetric alveolar infiltrates, but asymmetric, unilateral, and chronic patchy patterns were also noted. Diagnosis was established by thoracotomy-lung biopsy in 26 patients. Histologic analysis revealed uniform filling of the alveoli by periodic acid-Schiff-positive material and maintenance of normal alveolar architecture. Electron microscopy showed enlarged alveolar macrophages with lamellar osmiophilic inclusions, dense granules, and myeloid bodies. Of the 21 patients who underwent therapeutic bronchoalveolar lavage, 13 had no recurrence of the disease during a mean follow-up of 8.8 years. In patients who underwent pulmonary function testing both before and after lavage, significant restrictive dysfunctions present before the procedure were alleviated afterward. Three deaths occurred among the 34 patients. Pulmonary alveolar phospholipoproteinosis may result from defective clearance of phospholipids by the alveolar macrophages, excessive production of phospholipids by type II pneumocytes, or both. It is likely a nonspecific response to a variety of injuries to the alveolar macrophage or type II pneumocyte or both, including exposure to certain dusts and chemicals and occurrence of hematologic diseases or infections. The uncommon occurrence of this disorder suggests individual susceptibility.

Histologic, ultrastructural, chemical, and statistical methods were used to study liver biopsy and autopsy specimens from 43 patients who had primary sclerosing cholangitis (PSC), with or without chronic ulcerative colitis (CUC), and from 19 patients who had CUC without PSC. In all study groups, essentially the same abnormalities were found in the hepatic parenchyma outside the major bile ducts, although nondiagnostic tissue samples were observed also. Specimens from patients with extrahepatic PSC were indistinguishable from those patients with combined extra- and intrahepatic PSC. Common findings included periductal fibrosis and inflammation, portal edema and fibrosis, focal proliferation of bile ducts and ductules, focal bile duct obliteration and loss of bile ducts, copper deposition, and cholestasis. Proliferation of bile ducts in some portal tracts and obliteration or absence of bile duct in others were the most characteristic changes. In most specimens, inflammatory changes appeared mild, yet biliary cirrhosis had developed in 34% of the patients. Specimens from patients with PSC, with or without CUC, more often contained bile and strikingly increased stainable copper (Grades 2 and 3) than did specimens from patients with CUC without PSC. Hepatic copper contents, measured by atomic absorption spectrophotometry, also were higher in specimens from patients with PSC. Study of PCS specimens by transmission electron microscopy and by energy-dispersive X-ray microanalysis revealed that most copper was sequestered in lipolysosomes. The recognition of strikingly similar morphologic features in many liver specimens from patients with either PSC or CUC or both suggests that the causes of these conditions are closely related.

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