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Biomedical subjects

D Hopwood

Publications and source records attributed to D Hopwood.

At least 145 records · Page 8Linked to original sources
PubMed1977

Electron histochemistry of mucosubstances in normal human rectal epithelium.

The electron microscopic histochemistry of mucosubstances in sigmoidoscopically and microscopically normal rectal biopsies was studied using techniques currently available. The deposition of Alcian Blue and Ruthenium Red and the distribution of Concanavalin A receptors were limited to the epithelial cell borders. Mucosubstances in the fuzzy coat, Golgi apparatus, lysosomes and secretory vesicles were demonstrated by the periodic acid-chromic acid oxidation methods. Glycogen was demonstrated in the epithelium by periodate oxidation methods and the complex cyanide technique. There was little difference in the distribution of mucosubstances in the epithelial cells at any level of the crypts. Phosphotungstic acid staining under controlled conditions gave a similar distribution of mucosubstances to those revealed by the oxidation techniques.

Alcian Blue↗
PubMed1977

An ultrastructural study of osmiophilia in the human rectum.

Rectal biopsies from subjects with a normal rectum and from patients with various forms of inflammatory bowel disease were studied by the prolonged osmication technique. No consistent ultrastructural differences were observed between these groups, but there were striking differences between individual epithelial cells in the same biopsy and between the epithelium and the cells of the lamina propria. The Golgi apparatus was demonstrated occasionally in the epithelium, often in endothelium. Endoplasmic reticulum, perinuclear cisterna and mitochondria were variably outlined. In plasma cells, there were striking differences in osmiophilia. The underlying mechanism of the different staining patterns is not clear. The findings do not appear to help in the differential diagnosis of inflammatory bowel disease nor to shed any new light on their underlying pathogenic mechanisms.

Cell Membrane↗
PubMed1977

Effect of gallstone-dissolution therapy on human liver structure.

To assess potential toxic effects liver biopsies were performed before and after 6-8 months therapy with chenodeoxycholic acid (CDCA), 750 mg daily, in 6 patients with gallbladder stones. Minor fatty change and lipofuscin were seen prior to therapy, which tended to increase afterwards. Otherwise there was no consistent change on light microscopy. Electron microscopy showed parallel changes in the hepatocytes with no marked damage. There was a patchy loss of microvilli in the biliary epithelium. However, there was a significant increase in sinusoidal lipocytes or Ito cells, which was seen in every case. These 6 patients were representative of a group of 20 patients in whom serum liver function tests have been followed monthly for at least 6 months. During this period aspartate aminotransferase levels rose slightly but significantly, the mean remaining within the normal range. There was a trend to a decline in alpha-glutamyl transpeptidase levels, but this was less impressive and not statistically significant.

Aspartate Aminotransferases↗
PubMed1977

Potentiation of the action of azaserine on the rat pancreas by raw soya bean flour.

Rats were treated with raw soya flour to produce pancreatic hypertrophy and also received azaserine, a pancreatic carcinogen. The combined treatment resulted in the development of large numbers of hyperplastic nodules in the acinar tissue of the rat pancreas. We conclude that the pancreas of the rat stimulated to proliferate by raw soya flour provides a sensitive model for detecting and studying pancreatic carcinogens.

Animals↗
PubMed1977

Intercellular spaces and cell junctions in endometrial glands: their possible role in menstruation.

Intercellular spaces and cell junctions in human endometrial glands were studied by elctron microscopy following different methods of fixation. The size of the spaces, known to alter during the cycle, was found to depend also on the method of fixation. Various intrusive cells and different types of cell debris were seen in these spaces. The three most widely recognized cell junctions (desmosomes, tight junctions and gap junctions), were all most abundant near the cell apices. The possible significance of these findings in elucidating the cellular mechanism of menstruation is discussed.

Endometrium↗
PubMed1977

Liver ultrastructure in psoriatics related to methotrexate therapy. 1. A prospective study of findings in hepatocytes from 24 patients before and after methotrexate treatment.

To show what damage occurs in the hepatocytes of psoriatics receiving Methotrexate (MTX) therapy liver biopsies from 24 psoriatics with severe psoriasis before and after MTX therapy were studied blind by light and electron microscopy. We also aimed to determine the severity of lesions and find possible correlations, and to seek a relationship of these observations with light microscopical and clinical findings. The present study has shown that MTX probably caused damage to the hepatocytes reflected in the membrane whorls (p less than 0.05) and the accumulation of lipid droplets (p less than 0.05). There was an increase (p less than 0.05) in autophagic vacuoles, which mostly contained glycogen and cell sap with residual bodies. These residual bodies were then found in an increased number in the nearby Kupffer cells. Crystals were found in megamitochondria in most patients before and after MTX therapy. Some of these crystals were found free in the cytoplasm. Mitochondria containing crystals were shown in autophagic vacoules, representing possible pathways of their breakdown. Bile canaliculi commonly contained debris but only one patient had evidence of cholestasis. There was no significant change in nuclei, Golgi apparatus, or the endoplasmic reticulum and no statistically significant correlation between the shown changes and the total dose of MTX given.

Cell Membrane↗
PubMed1977

Liver ultrastructure in psoriatics related to methotrexate therapy. 2. Findings in bile ducts from 11 methotrexate treated psoriatics and 2 controls.

To determinate what damage occurred in the bile ducts of psoriatics receiving Methotrexate (MTX) therapy liver biopsies from 11 patients were studied with the light and electron microscope and compared with normal material. Thick sections (1 micrometer) showed light and dark cells in biliary epithelium and lipofuscin granules. At the ultrastructural level these were confirmed. The lumen of the bile ducts contained debris. The microvilli were decreased in number and damaged forms appeared. Damage to the biliary epithelial mitochondria was widespread and there were foci of intracellular oedema. The Golgi apparatus was hypertrophied and dilated. Atrophic cells were seen. The lateral intercellular spaces were dilated and contained debris and the basement membrane showed zones of duplication. Similar changes were found in the ducts of Hering.

Adult↗
PubMed1976

Atrophy and apoptosis in the cyclical human endometrium.

Electron microscopy of human cyclical endometrium indicates that there is considerable loss of gland epithelial cells with formation of apoptotic bodies in the late secretory, premenstrual and menstrual phases, but also to a lesser extent in the proliferative phase. Apoptotic bodies containing nuclear fragments may be recognised on light microscopy as basophilic or Feulgen positive granules. These granules accumulate in greatest numbers towards the end of the cycle and may be used as an additional aid in dating curettings.

Atrophy↗
PubMed1976

Effect of methotrexate therapy in psoriatics on the Ito cells in liver biopsies, assessed by point-counting.

To evaluate the relationship, both quantitative and qualitative, between the Ito cells and methotrexate (MTX) therapy Ito cells were studied by light microscopy in 1 mum toluidine blue stained sections and by electron microscopy in 24 pairs of Menghini needle biopsies before and after MTX therapy of 24 consenting patients with severe psoriasis. Light microscopy showed a statistically significant increase in pathological findings (P less than 0-05) and in the number of Ito cells and their size (P less than 0-0001) after MTX therapy. It was not possible to show a statistically significant correlation between the increase in the number of Ito cells and the cumulative dose of MTX. Ultrastructural analysis of Ito cells showed no marked difference from pre to post-MTX specimens. The fibrosis and cirrhosis seen after MTX therapy in some liver biopsies from psoriatics and the post-MTX increase in the number of Ito cells direct attention to the possible role of Ito cells as fibroblast precursors.

Adult↗
PubMed1975

The reactions of glutaraldehyde with nucleic acids.

The kinetics of the reactions between glutaraldehyde, RNA and DNA have been investigated. At temperatures up to 64 degree C no reaction occurred between native DNA and glutaraldehyde. At temperatures above 75 degree C the reaction followed pseudofirst order kinetics, proceeding more quickly at higher temperatures. Reactions between RNA and glutaraldehyde were similar, except that they began above 45 degree C. These findings were corroborated by thermal transition profiles. There was little evidence for the formation of cross-links between nucleic acid molecules even at elevated temperatures.

Aldehydes↗
PubMed1972

Ultrastructural findings in idiopathic recurrent cholestasis.

Needle liver biopsies of patients with idiopathic recurrent cholestasis were studied by light and electron microscopy. Many hepatocytes showed non-specific damage to their organelles. Crystalloids were found both in the cytoplasm and within mitochondria in one patient. The microscopic and clinical findings were interpreted as being in favour of primary hepatocyte injury.

Adult↗