The extraction of smooth muscle contractile and noncontractile proteins from the rat small intestine: measurement of protein synthesis and effects of ethanol toxicity.

An investigation was made into the optimum conditions for the extraction and measurement of intestinal smooth muscle contractile proteins of laboratory rats. Isolation of the seromuscular layer was achieved by "mucosal stripping" (using a glass slide); isolation of contractile proteins were achieved by differential solubility (using high and low ionic buffers and ultracentrifugation). Histological evidence revealed that after mucosal striping all cells of the longitudinal and circular muscle layers of the seromuscular region remained intact. Assay of brush-border marker enzyme activities confirmed that mucosal striping did indeed remove the mucosa and there was very little villus contamination of the smooth muscle tissue preparations. Optimum physical conditions for the isolation of seromuscular and mucosal myofibrillary proteins were identified. We ascertained that considerable amounts of myofibrillarly proteins reside in the mucosa, but could be adequately separated by mucosal striping. Improved recoveries of purified contractile proteins necessitated the inclusion of protease inhibitors during all processing steps. Using the optimum method, polyacrylamide gel electrophoresis of contractile proteins showed that the predominant smooth muscle contractile proteins, i.e., myosin heavy chain, actin, tropomyosin, and myosin light chains, were indeed preferentially isolated by our methodology. Using these techniques we demonstrated that the synthesis rates of intestinal contractile proteins were reduced by acute ethanol dosage. These results may be responsible for, or reflect, alcohol-induced defects in intestinal motility.

Ethanol-induced skeletal muscle myopathy: biochemical and histochemical measurements on type I and type II fibre-rich muscles in the young rat.

Rats were pair-fed either a nutritionally complete liquid diet containing 36% of total calories as ethanol or isovolumetric amounts of the same diet in which ethanol was substituted by isocaloric glucose. Chronic ethanol feeding caused a preferential decline in the wet weight of the plantaris (predominantly Type II muscle fibres) which was accompanied by a reduction in the total DNA content. The soleus (a predominantly Type I fibre muscle) was relatively unaffected. Chronic ethanol exposure had no effect on the biochemical index of cell size (protein/DNA ratio) in either the plantaris or soleus. Quantitative histochemistry of Type II fibres in the plantaris demonstrated that ethanol caused an increase in the proportion of fibres with smaller diameters. Similar effects were observed for Type II fibres in the soleus. In contrast, ethanol exposure was associated with an increase in the relative proportion of Type I fibres with higher diameters, in both plantaris and soleus. Light microscopic examination of myopathic muscle sections demonstrated that lesions occurred without evidence of inflammation, fibrosis or other infiltration by non-muscle cells. It is concluded that chronic exposure of rats to ethanol is associated with skeletal muscle atrophy. The lesion appears to be specific for Type II fibres, irrespective of the predominant fibre type in the particular muscle.

Pure red cell aplasia.

Complete or near complete remission of acquired pure red cell aplasia, not associated with thymoma, occurred in response to prednisone (six occasions), prednisone and cyclophosphamide (twice), cyclophosphamide alone (once) and splenectomy (once). These results were observed in four patients and confirm the value of cyclophosphamide and possibly splenectomy in patients resistant to prednisone in acquired red cell aplasia. In two of these patients, bone marrow progression from a state of ineffective erythropoiesis with many red cell precursors to that of red cell aplasia was observed. This indicates that some acquired refractory anaemias characterized by ineffective erythropoiesis may have the same pathogenesis as acquired red cell aplasia. The absence of demonstrable antibodies active against erythroblasts may merely reflect the insensitivity of currently available techniques. However it is possible that non-humoral immune mechanisms may be involved in the production of some forms of acquired red cell aplasia responsive to immunosuppressive drugs.

Long-term haematological complications of thorotrast.

Six cases representing the spectrum of haematological complications due to systemic administration of Thorotrast are reposted. Two patients suffered from acute leukaemia, one patient had marrow failure and three patients presented with haematological features of hyposplenism; two of these also had solid tumours. The literature is reviewed.

Hypoplastic acute myelogenous leukaemia.

The clinical course, diagnosis and management of nine cases of hypoplastic acute myelogenous leukaemia are described. Such cases may follow a slowly progressive course and should not receive anti-leukaemic chemotherapy unless the disease is advancing rapidly or unless some specific complication develops. If chemotherapy has to be given, usually because of severe and recurrent infections, then prompt and prolonged remission of disease may occur.

Factors influencing prognosis in adults with acute myelogenous leukaemia.

A study of the thymidine labelling index (TLI) of bone marrow blast cells in 58 untreated patients with acute myelogenous leukemia showed no correlation with remission rate but there was a strong correlation between labelling index and remission length in the 21 patients who achieved remission. The median remission length of the patients was 33 weeks. Of the 12 patients with initial labelling indices greater than 10%, only 2 had remissions longer than 33 weeks whereas 8 of the 9 patients with labelling indices less than 10% had remissions longer than 33 weeks. No correlation could be found between the degree of cytological differentiation and remission induction, remission length or survival. No correlation was found between the TLI and the degree of cytological differentiation. Age and initial platelet count were confirmed to be important factors influencing complete remission rate, but these factors did not correlate with remission length. Sixteen patients had their pretreatment sera assayed for mouse marrow colony stimulating activity and inhibitor levels but there was no correlation with subsequent response to treatment, although the number of patients examined was clearly too small for any definite conclusions to be drawn.

Immunotherapy for acute myelogenous leukaemia.

One hundred and seven untreated patients with acute myelogenous leukaemia (AML) were admitted to St Bartholomew's Hospital between 10 October 1970 and 31 January 1973. Before receiving drugs to induce remission they were allocated alternatively into 2 groups to decide their remission treatment-a group to receive chemotherapy alone and a group to receive the same chemotherapy with immunotherapy. The patients were then given induction chemotherapy and 45 of them attained complete remission. All patients in remission then received chemotherapy consisting of 5 days treatment every 28 days. Patients receiving immunotherapy were also given multiple weekly intradermal injections of irradiated stored AML cells and Glaxo B.C.G. using a Heaf gun. There were 19 patients in the group which received only chemotherapy during remission; 7 of these patients remain alive (median survival after attaining remission 303 days) and only 5 are still in their first remission (median remission length 188 days). Twenty-three patients were allocated to receive immunotherapy during remission in addition to chemotherapy and 16 remain alive (median 545 days) and 8 are in their first remission (median 312 days). The difference in survival of the two groups is significant with a P value of 0·003.

Management of adult acute myelogenous leukaemia.

Consecutive adult patients admitted to St. Bartholomew's Hospital with acute myelogenous leukaemia have been treated with a remission induction drug schedule consisting of daunorubicin and cytosine arabinoside. Intermittent five-day courses were used in 72 patients, and a complete remission was obtained in 39 patients (54%). An alternative drug schedule in 22 patients resulted in fewer remissions but this may have been due to age differences in the two groups. Age and initial platelet count were found to be important factors in determining the success of remission induction therapy; the older patients and those with low platelet counts responded less well.A series of 23 patients who achieved remissions was divided into two groups; one received intermittent combination chemotherapy as the only form of maintenance, and the other was given weekly immunotherapy in addition to the chemotherapy. The immunotherapy consisted of irradiated allogeneic leukaemic cells and B.C.G. Eight of the 10 patients on chemotherapy alone have already relapsed compared with five out of 13 patients in the immunotherapy group. It is hoped that these promising initial results with this form of maintenance will be confirmed as more patients enter the maintenance trials.

Adriamycin in the treatment of acute leukaemia.

In a preliminary study a new antitumour antibiotic, adriamycin, was found to be capable of inducing complete remission in 6 out of 17 patients with acute lymphoblastic leukaemia and in one out of four with lymphoblastic lymphosarcoma despite the fact that these patients had either failed to respond or had relapsed after chemotherapy with agents recognized to be potentially successful in each condition. In five cases of acute lymphoblastic leukaemia adriamycin was used in combination with cytosine arabinoside-three achieved complete remission and two good partial remissions. This combination seems to merit further study in patients who have relapsed on the more conventional chemotherapeutic regimens in acute lymphoblastic leukaemia.In 13 patients with acute myelogenous leukaemia previously treated with daunorubicin and cytosine arabinoside no remissions were obtained with the dose range used.