Ian A. R. More

ATUBULAR GLOMERULI AND GLOMERULAR CYSTS—A POSSIBLE PATHWAY FOR NEPHRON LOSS IN THE HUMAN KIDNEY?

Glomerular tufts were removed and scanning electron microscopy was used to study the interior of Bowmans capsule, in order to identify atubular glomeruli. Normal renal cortex was studied from six kidneys removed for tumour and six renal transplants removed for end‐stage rejection. Atubular glomeruli occurred in normal renal cortex in less than 1 percent of glomeruli, but were more common in transplant nephropathy, representing up to 61 percent of glomeruli.

REAPPRAISAL OF THE ULTRASTRUCTURE OF THE HUMAN ENDOMETRIAL GLANDULAR CELL

A survey of the ultrastructure of histologically normal endometrial biopsies from 30 women at various stages of the menstrual cycle was made. The nucleus and nucleolus showed morphological variations in the different phases of the cycle which could be correlated with the changing metabolic needs of the cytoplasm. During the ovulatory phase, glycogen, giant mitochondria and nucleolar basket formation were observed and the functional morphology of the latter two organelles is discussed. The secretory phase was characterized by the apocrine and merocrine secretion of glycogen and glycoprotein, as well as by age changes and ultimate cellular breakdown.

Tuft-to-capsule adhesions and their precursors: differences between the vascular and tubular poles of the human glomerulus

Human glomerular capillary tufts were removed by microdissection and scanning electron microscopy was used to examine the surface of the capillary tuft and the interior of its Bowmans capsule in order to identify connections between the tuft and capsule. Glomeruli were examined in histologically normal renal cortex from 12 kidneys removed for tumour and 12 renal allografts removed for end‐stage rejection. In normal kidney, the glomerular tuft was connected to Bowmans capsule by single podocytes and their processes. At the vascular pole, these were predominantly associated with parietal podocytes which lined Bowmans capsule. At the tubular pole, occasional podocytic processes derived from the capillary tuft bridged Bowmans space and connected to Bowmans capsule where there were no parietal podocytes. These podocytic connections were also found in all rejected transplants, but in addition adhesions were identified which consisted of thicker connections between the tuft and capsule. At the vascular pole, tuft‐to‐capsule adhesions were found in all 12 kidneys; these were always associated with parietal podocytes. Tubular pole adhesions were identified in ten of the 12 transplants. They were associated with abnormal squamous cells, but not with parietal podocytes. When the capillary tuft herniated into the proximal tubule, the tuft sometimes formed an adhesion with the origin of the proximal tubule. These observations suggest that podocyte connections between the glomerular tuft and Bowmans capsule may be precursors of glomerular adhesions at the vascular pole. Since tuft‐to‐capsule adhesions at the vascular pole differ morphologically from those at the tubular pole, this may reflect different pathogenetic mechanisms at the opposite poles of the glomerulus.

Thirteen new mammary tumor cell lines from different mouse strains

Abstract Seventeen mammary tumors transplantable in various strains of mice were cultured to obtain established cell lines. All but four tumors have been successfully established as monolayers, have been subcultured regularly, and produced tumors on inoculation into syngeneic mice. Histological examination showed that seven lines (SHF and SHK in C3H mice, S6C in ACA mice, S3W in ASW mice, S2Y in ABY mice, SBfnHA and SBfnHB in CBA mice) are adenocarcinomas, three (TA3Ha, TA3St in A mice and SBfnHD in CBA mice) are poorly differentiated carcinomas, and three (SHG in C3H mice, S40C in ACA mice and SBfnHC in CBA mice) are spindle celled, ‘sarcoma-like’ tumors associated with much reticulin and collagen. Electron-microscopy demonstrated that all lines, including the ‘sarcoma-like’ SHG, S40C and SBfnHC are carcinomatous. Eleven lines showed secretion vacuoles consistent with the presence of milk protein. SHG, S40C and SBfnHC are thus to be regarded as spindlecelled carcinomas. All cell lines, except SHG and SBfnHC, were sensitive to antimammary tumor virus serum. SHK, S2Y and SBfnHB showed extremely high reactivity to this antiserum. These thirteen established cultured lines promise to be useful in the further study of mouse mammary tumors.

CYCLICAL CHANGES IN THE ULTRASTRUCTURE OF THE NORMAL HUMAN ENDOMETRIAL STROMAL CELL

A survey of the ultrastructure of the stromal cell in histological normal endometrial biopsies from 41 women at various stages of the menstrual cycle was made. The nucleus and nucleolus showed structural changes which could be correlated with the metabolic activity of the cell at various stages of the cycle. The latter stages of the cycle were characterized by the differentiation of the stromal cells into two distinct cell lines; the predecidual cell and the endometrial granulocyte. The cyclical changes were compared with those occurring in the endometrial glandular cell and the autonomy of the stromal cell is discussed.

A scanning electron-microscopic study of the peripolar cell of the rat renal glomerulus

SummaryThe interior of Bowmans capsules of rat kidneys has been examined by scanning electron microscopy, and a distinctive population of cells around the exposed vascular poles of glomerular tufts were identified. The cells were situated in the annular groove at the root of the glomerulus, between the parietal epithelial cells and the podocytes. These peripolar cells were dendritic cells with long processes embracing the glomerular arterioles. Up to three peripolar cells were present at each vascular pole and they were mainly distributed in the glomeruli of the outer third of the renal cortex. This first detailed study of the surface morphology of the glomerular peripolar cell supports the suggestion that changes in the diameter of the polar region of the glomerular tuft may cause variations in stretching of the cuff of peripolar cells, and hence modulation of their secretory activity.

Viral expression and immunogenicity of CBA mammary carcinomas and their hybrid lines with an L-cell derivative (A9HT)☆

Abstract Somatic cell hybrid lines were obtained by Sendai virus mediated fusion of a highly tumorigenic variant of L-cell subline A9 of C3H mouse origin (A9HT) with two CBA mouse mammary carcinomas (SBfnHA and SBfnHC) that had been inoculated into CBAT6 mice. Hybridity was confirmed by the presence of biarmed marker chromosomes from the A9HT parent, and the total chromosome number, which in both hybrids (SBfnHA/A9HT and SBfnHC/A9HT) approximated the sum of the parental chromosomes. The absence of the T6 marker in both the hybrids confirmed that fusion was not between a stroma cell from CBAT6 mice and A9HT. Both hybrids showed spindle cell carcinoma morphology. Complement dependent cytotoxicity assays revealed that SBfnHA and A9HT expressed the MTV-associated antigens including one major structural component, gp52 and the MuLV structural components gp71. and p30 on the cell-surface, while SBfnHC expressed only gp71. The hybrid line SBfnHA/A9HT lost the surface expression of MTV gp52 and MuLVp30, and there was also decreased expression of gp71 in comparison with SBfnHA. In contrast, in SBfnHC/A9HT there was increased expression of gp71 over that of SBfnHC. All parental and hybrid lines had unchanged sensitivity to the cytotoxic effect of anti-H-2 k sera. Immunization of CBA mice with heavily irradiated either syngeneic SBfnHA or hybrid SBfnHA/A9HT cells, followed by challenge with viable SBfnHA cells revealed that SBfnHA was a highly immunogenic tumor, while the hybrid line SBfnHA/A9HT decreased in the immunogenicity of the parental SBfnHA line. On the other hand, immunization of CBA mice with heavily irradiated either syngeneic SBfnHC or hybrid SBfnHC/A9HT cells, followed by challenge with viable SBfnHC cells showed that SBfnHC/A9HT slightly increased the very low immunogenicity of the parental SBfnHC. These results are consistent with the possibility that MTV-and MuLV-associated cell-surface antigens influence the immunogenicity of CBA mammary carcinomas.

Non-granulated peripolar cells exist in the rat glomerulus

SummaryThe peripolar cell is a unique cell type in the mammalian glomerulus. Peripolar cells are said to be identifiable during light microscopy by their cytoplasmic granules and by their position at the vascular pole; and during scanning electron microscopy by their distinctive surface morphology. We used both techniques to count peripolar cells in 6 normal rat kidneys. Scanning microscopy revealed that 55(±5)% of glomeruli contained at least one peripolar cell whereas light microscopy revealed granulated peripolar cells in only 4(±2)% of glomeruli. Vascular poles which contained peripolar cells previously identified by scanning were then examined by light and by transmission electron microscopy. Serial sections through these peripolar cells demonstrated the absence of cytoplasmic granules. Our observations suggest that the majority of peripolar cells in the rat contain no granules.