ADP-ribosyl transferase, rearrangement of DNA, and cell differentiation

Cell differentiation is the process by which genetic information is selectively expressed to produce cells with various morphologies and functions. The integrated changes necessary for this fundamentally important process have recently been the subject of intense study. This review will summarize data from several laboratories correlating differentiation with the activity of the enzyme ADP-ribosyl transferase and with changes in single-strand DNA breaks in various diverse eukaryotic systems. We will then discuss the implications of these observations for differentiation in general, including the possibility that rearrangement of genetic material is a widespread mechanism for controlling gene expression.

Granulomatous inflammation--a review

The granulomatous inflammatory response is a special type of chronic inflammation characterised by often focal collections of macrophages, epithelioid cells and multinucleated giant cells. In this review the characteristics of these cells of the mononuclear phagocyte series are considered, with particular reference to the properties of epithelioid cells and the formation of multinucleated giant cells. The initiation and development of granulomatous inflammation is discussed, stressing the importance of persistence of the inciting agent and the complex role of the immune system, not only in the perpetuation of the granulomatous response but also in the development of necrosis and fibrosis.

Direct radioactive labelling of poly(ADP-ribose) in developing Xenopus laevis embryos

It has not previously been possible to label the nuclear protein modification poly(ADP-ribose) directly from NAD because of the impermeability of the cell membrane. We have overcome this important problem by micro-injection of radioactively labelled NAD into Xenopus laevis early embryos. The polymer was identified and then quantified by its insensitivity to DNAase, RNAase, and spleen phosphodiesterase and by the chromatographic mobility of the products of digestion with snake-venom phosphodiesterase. The quantity of poly(ADP-ribose) present after 25 h of development (129 ng/mg DNA) is lower than that found in fully differentiated tissue.

NAD turnover during early development of Xenopus laevis

The NAD pools of Xenopus laevis oocytes and early embryos can be radioactively labelled by microinjection of [adenine-3H]NAD. This technique is used to study the metabolism of NAD in oocytes and during early development. The rate at which NAD is degraded in vivo has been monitored by determining the rate of transfer of adenine residues from the NAD pool into other nucleotides and polynucleotides. In oocytes, NAD turnover is extremely slow, with a half-life of about 400 h. NAD turnover increases dramatically after fertilisation, and the half-life of the compound decreases to 37 h in 5-h-old embryos and to 10 h in 40-h-old embryos. 2 mM 3-aminobenzamide, a specific inhibitor of poly(ADP-ribose) polymerase, reduces the NAD turnover rate by about 20%, whereas 5 mM isonicotinic acid hydrazide, a specific inhibitor of NAD glycohydrolase, produces no significant inhibition. This indicates that a significant fraction of the considerable NAD turnover observed involves poly(ADP-ribose) polymerase. Our results indicate that poly(ADP-ribose) polymerase is active during early development and suggest that this activity may be involved in one or more aspects of the nuclear metabolism of the embryo.

Fractionation of membrane proteins on phenylboronic acid-agarose

Detergent-solubilized plasma-membrane proteins from lymphocytes of patients with chronic lymphocytic leukaemia were applied to phenylboronic acid-agarose. Some of the polypeptides were bound specifically and subsequently eluted with sorbitol. Immunoprecipitation analyses showed that no surface immunoglobulin M was bound, but that most of the histocompatibility antigens HLA-A, HLA-B, HLA-C and HLA-DR were.

Growth of Trypanosoma cruzi in vitro: development and application of a continuous-flow culture system

The design and operation of a modular, bacteriological continuous-flow culture system have been adapted for the growth of Trypanosoma cruzi epimastigotes in simple monophasic media. The system was designed to achieve a minimum of 200 days of continuous culture and provision was made for the continuous supply of medium and collection of parasites under sterile conditions. The system provides large quantities of epimastigotes with homogeneous morphology and uniform viability. The system also lends itself to the analysis of the factors which affect parasite growth. We examined the effects of changes in environmental parameters on epimastigote growth rate. Optimal growth was observed at 27 degrees C. The rate of stirring of the culture had a small but definable effect on the growth rate, which was greatest at 80 rp.m. Growth was only slightly affected by the level of dissolved oxygen between 10 and 50% saturation, but was inhibited at higher concentrations. Growth was slower at extreme values of pH but showed a broad optimum around pH 7.4.

Isolated epithelioid cells from disaggregated BCG granulomas - some functional studies

Isolated epithelial cells from disaggregated rat BCG granulomas show a morphological spectrum from "plasmacytoid" to "vesicular" froms on electron microscopy. Functional studies on these isolated cells showed that all epithelial cells exhibited poor trypsin-resistant glass adherence and poor phagocytosis of latex, zymosan, antibody coated and complement coated and complement coated erythrocytes when compared with macrophages, especially at the vesicular end of the spectrum. A high proportion of all epithelioid cell types was found to have Fc surface receptors but C3 receptors were reduced on vesicular cells compared with the plasmacytoid variety. The findings indicate that the progressive transformation of mononuclear phagocytes into vesicular epithelioid cells through plasmacytoid intermediates is accompanied by a concomitant modification of cell function. The significance of these changes is discussed.

Isolated epithelioid cells from disaggregated BCG granulomas - an ultrastructural study

Non-caseating epithelioid granulomas have been induced in rats by the subcutaneous injection of BCG vaccine and their cellular disaggregation to yield isolated epithelioid cells has been achieved using collagenase. Ultrastructurally epithelioid cells in both intact granulomas and disaggregated cell suspensions showed a spectrum of appearances ranging from cells with conspicuous rough surfaced endoplasmic reticulum ("plasmacytoid epithelioid cells") to cells containing numerous cytoplasmic membrane-bound vesicles ("vesicular epithelioid cells"). Numerous intermediate forms were present. Endocytosed material was inconspicuous. Investigation of disaggregated 4, 10 and 28 day lesions showed that the proportion of vesicular epithelioid cells increased with maturation of the granulomas. Nevertheless a full spectrum of epithelioid cell morphology was present as early as 4 days. It is suggested that mononuclear phagocyte cells entering the granuloma transform into vesicular epithelioid cells via an intermediate plasmacytoid stage. The successful isolation of viable epithelioid cells from granulomas may allow the function of these cells to be evaluated further.

Gastric-juice enzymes--an aid in the diagnosis of gastric cancer?

Lactic dehydrogenase (LDH) and beta-glucuronidase concentrations were measured in the resting gastric juice of 113 patients presenting with dyspepsia. All patients were investigated by double-contrast barium meal, endoscopy with biopsy, and, when appropriate, by laparotomy. In all patients tested there was a positive correlation between LDH and beta-glucuronidase concentrations. An index derived from the two enzyme activities correctly predicted the presence of gastric carcinoma in 41 out of 42 cases, and identified the only 2 cases of early gastric cancer in the series. There were 13 (11.5%) false-positive results, all in cases with extensive intestinal metaplasia, a change which may be associated with an increased risk of gastric malignancy. The measurement of gastric-juice enzymes is useful in the diagnosis of gastric cancer and may be of value in the identification of high-risk groups. The test is easily performed, inexpensive, and reproducible.

Computed tomography and histological correlation of the thymic remnant

Pre-operative computed tomography (CT) of the anterior mediastinum was performed in eight patients undergoing surgery for cardiac conditions. At operation the anterior mediastinum was generously biopsied. Histology of the material allowed evaluation of the proportion of normal residual thymic tissue. Wide variation in CT appearances and in the degree of thymic involution was found, but there was good correlation between CT findings and thymic histology. This normal variation is of importance when considering the CT diagnosis of anterior mediastinal soft tissue density tumours.

Depth of ulceration in acute colitis: correlation with outcome and clinical and radiologic features

The depth of colonic ulceration has been graded histologically in 40 patients treated by urgent colectomy for acute colitis. Dilatation of the colon occurred in only 2 of 16 patients with ulceration limited to the submucosa, but in 18 of 24 patients with ulceration which extended into the muscle layer. Perforation occurred in 4 of the 6 patients in whom ulceration was seen to penetrate the muscle completely; the only two deaths occurred among these 4 patients. Complications of colitis thus correlated with the depth of ulceration. The clinical, laboratory, and radiologic features just before operation have been correlated with the depth of ulceration. While there was tendency for anorexia, abdominal tenderness on palpation, fever, tachycardia, leucocytosis, and hypoproteinemia to occur more commonly as the depth of ulceration increased, no single feature or combination of these features correlated well with ulcer depth. A colonic segment exceeding 5 cm in diameter with an irregular mucosal edge, outlined by gas on a plain abdominal radiograph, correlated strongly with ulceration involving the colonic muscle.

Metaplastic polyps and polyposis of the colorectum

Five hundred and fifty-four colorectal metaplastic polyps have been studied histologically. Whilst most lesions were small and sessile, 16.1% measured greater than 0.5 cm in diameter and 0.9% were greater than 1 cm. The larger polyps were frequently pedunculated and occasionally showed a tubulo-villous or villous pattern. A structural similarity between the larger metaplastic polyps and colorectal adenomas is illustrated and the importance of the distinction of metaplastic from dysplastic epithelium in the differentiation of these lesions is stressed. Other unusual features of metaplastic polyps are described. Evidence is given to suggest that males have a greater propensity to develop metaplastic polyps than females. A search for men adenomas, but relatively frequent (20.8%) in juvenile polyps. Finally, seven patients with multiple metaplastic polyps of the colorectum are described, in whom a diagnosis of adenomatous polyposis had been made at some stage in their management. Six of the seven patients were males and the mean age at presentation was 37.4 years. Larger metaplastic polyps were frequent in these cases. The necessity for histological confirmation in all cases of intestinal polyposis is stressed, and the possibility that 'metaplastic polyposis' is a pathological entity is discussed.

Squamous carcinoma of the colorectum and its genesis

A case of pure aquamous carcinoma of the rectum is presented, and the literature reviewed. Squamous carcinomas of the colorectum are rare tumours which have clinicopathological features in common with adenocarcinomas. Evidence is presented to support the proposal that most tumours of the large intestine that consist partly or completely of squamous elements arise from areas of squamous differentiation in pre-existing adenomas. The pathogenesis of squamous carcinoma and adenosquamous carcinoma appears to be similar to that of adenocarcinoma.

Neutropenia during treatment of rheumatoid arthritis with levamisole

Of 60 patients with rheumatoid arthritis treated with levamisole 35% showed a persistent decrease in neutrophil counts from pre-treatment levels and 6 (10%) develped severe neutropenia of less than 1.0 X 10(9)/1. One of these neutropenic patients recoverd without stopping therapy and the other 5 patients recovered rapidly when the drug was withdrawn. In some patients neutropenia recurred on reinstitution of levamisole.

Bacteraemia in a London teaching hospital 1966-75

Analysis of blood-cultures done at St. Bartholomew's Hospital over the decade 1966-75 has revealed a five-fold increase in the incidence of bacteraemia. This increase was particularly prominent in patients with non-malignant disease. The predominance of bacteraemia caused by gram-negative organisms declined in recent years, whereas bacteraemia due to gram-positive organisms, anaerobes, and Candida spp. increased. A recent increase in the number of blood-cultures performed was associated with the introduction of commercially prepared bottles. This led to a higher rate of investigation of patients who ultimately proved to have negative results, and also to a higher incidence of contamination which exceeded the positivity-rate.

Percutaneous teflon injection of a vocal cord under fibre optic laryngoscopic control

The technique of percutaneous injection of Teflon paste into a paralysed abducted vocal cord using a fibre optic laryngoscope to observe and control the effect is described. Its use in vocal cord paralysis caused by inoperable bronchogenic carcinoma and the results in 14 patients are discussed.

Fibreoptic laryngoscopy in the assessment of laryngeal disorders

The fibreoptic laryngoscope is described, and its method of use detailed. Seventy patients were submitted to this examination. Its advantages and disadvantages in the assessment of the various groups of laryngeal disorders in these patients are discussed and compared with indirect and direct laryngoscopy. Its teaching and research possibilities are also mentioned. The technique shows considerable promise and will, we believe, achieve an accepted place as an addition to our diagnostic armamentarium in the investigation of laryngeal disorders.

Spontaneous rupture of the pharynx

A case of spontaneous rupture of the pharynx is described occurring during the act of vomiting. Comparisons are made with the only known previously recorded case of spontaneous pharyngeal rupture.