H-77: a potent new renin inhibitor. In vitro and in vivo studies

Chemical modification of the backbone at the cleavage site in the (6-13)-octapeptide of equine angiotensinogen resulted in greatly increased binding affinity and resistance to cleavage by renin. The D-His6-Tyr13 octapeptide analog containing the reduced bond -CH2-NH-instead of a peptide bond -CO-NH- at the Leu10-Leu11 linkage (H-77) was a powerful in vitro inhibitor of canine renin (IC50 = 24nM). It gave an IC50 of 1 microM against human renin and 0.6 microM against rat renin. In sodium-depleted conscious dogs, infusion of H-77 caused dose-related falls of plasma angiotensin I plasma angiotensin II concentration and mean arterial pressure; the minimum effective dose was 0.1 mg . kg-1 hr-1. Similar infusions of H-77 in chronically catheterized rats have no effect on blood pressure or plasma angiotensin II concentration. Thus, the in vitro effect of H-77 as an inhibitor of renin in dog, human, and rat plasma was paralleled by its action in the whole animal.

Adults' cognitive demands at home and at nursery school

A study was made of the "cognitive demands" made of children during spontaneous conversations with their teachers at nursery school and their mothers at home. Social class differences were small compared with home/school differences. Teachers' talk contained a higher proportion of cognitive demands and "testing" demands than did mothers' talk; however, the hourly rate of these demands was higher in the mothers' talk. Teachers used more demands for attributes, simple descriptions and interpretations, whilst mothers used more demands for recall and explanation of motives and purposes. More demands were left unanswered at school than at home. The implications for nursery education are discussed.

Morphology and kinetics of erythropoiesis in haemoglobin H disease

Some aspects of erythroblast function have been investigated in two Thai patients with haemoglobin H disease. Electron microscope and high resolution autoradiographic studies revealed that (1) some erythroblasts and marrow reticulocytes contained branching intracytoplasmic inclusions and (2) the presence of such inclusions did not necessarily prevent the entry of cells either from the G1 phase into the S phase or from the G2 phase into mitosis. The distribution of early polychromatic erythroblasts in the different stages of the cell cycle was determined by the technique of combined Feulgen microspectrophotometry and 3H-thymidine autoradiography and found to be essentially normal. It is concluded that although the presence of an excess of alpha-chains in the beta-thalassaemia syndromes has been previously shown to be associated with a gross impairment of erythroblast proliferation, the presence of an excess beta-chains in HbH disease is not.

Ineffective erythropoiesis in haemoglobin E beta -thalassaemia: an electron microscope study

Electron microscope studies have been performed on the bone marrow cells of two non-splenectomized patients and the circulating erythroblasts and reticulocytes of three splenectomized patients with HbE/beta-thalassaemia. Some intracellular precipitates (probably consisting of alpha-chains) and mild dyserythropoietic changes were found in the early polychromatic erythroblasts within the bone marrow. Larger quantities of precipitate and more marked dyserythropoietic changes were found in the late polychromatic erythroblasts and reticulocytes both within the marrow and within the circulation. The bone marrow macrophages contained phagocytosed erythroblasts within their cytoplasm. These data indicate that the anaemia in HbE/beta-thalassaemia results largely from dyserythropoiesis and ineffective erythropoiesis. The ultrastructural abnormalities encountered in the cases of HbE/beta-thalassaemia were qualitatively and quantitatively similar to those seen in homozygous beta-thalassaemia.

Ultrastructure of red cells containing haemoglobin H inclusions induced by redox dyes

Electron microscope studies have been performed to investigate the ultrastructural basis of the characteristic golf-ball-like light microscope appearance which develops when the erythrocytes of patients with HbH disease are stained supravitally with brilliant cresyl blue or new methylene blue. The data indicate that the golf-ball appearance resulted from the formation of many spherical or biconvex masses of electron-dense material which were attached to and which bulged the cell membrane. These masses presumably consisted of denatured HbH. A variable proportion of the red cells of the four patients investigated failed to form such membrane-associated inclusions even after treatment with redox dyes for 24 h. Studies of subpopulations of red cells which were separated according to cell age suggested that there was a considerable variation in the HbH content of young red cells and indicated that with increasing cell age there is an increase in the proportion of red cells which do not contain appreciable quantities of HbH.

Can alphabet recall be part of a visuo-spatial task?

Fifty male and 50 female undergraduates were subjects in an experiment where they were required to recall the alphabet and to count either the number of letters containing the sound 'ee' or the number of letters with curves in the upper-case form. The results fail to replicate those of Coltheart et al. (1975), but are consistent with current models of hemispheric specialization. Males were found to complete the visuo-spatial task slower than the females and it is argued that this is due to their greater degree of hemispheric specialization which necessitates transfer of information between hemispheres.

Ultrastructural studies of erythropoiesis in beta-thalassaemia trait

The erythropoietic cells of six cases of beta-thalassaemia trait were studied by electron microscopy and electron microscope autoradiography. Intracytoplasmic and intranuclear alpha-chain precipitates were found in some late polychromatic erythroblasts and intracytoplasmic precipitates were found in several marrow reticulocytes. This provides direct morphological evidence of unbalanced globin chain synthesis in the marrow. Several of the polychromatic erythroblasts and marrow reticulocytes contained autophagic vacuoles and showed a variety of other dyserythropoietic changes. Erythroblast profiles containing moderate quantities of precipitated alpha-chains usually suffered from a marked depression of protein synthesis. The proportions of marrow cells containing alpha-chain precipitates and displaying dyserythropoietic changes varied considerably from patient to patient. It is proposed that this variation largely reflects variations in the proteolytic capacity of the erythropoietic cells in different individuals and leads to different degrees of ineffective erythropoiesis in beta-thalassaemia trait.

The anaemia of P. falciparum malaria

The haematological changes in a group of young Gambian children with P. falciparum malaria have been analysed. In children with acute infection anaemia was most marked during the period after treatment. Although many of these patients developed a positive direct Coombs test during this period of the illness it is not clear whether the anaemia which occurs after treatment has an immune basis. A second group of children showed quite different haematological findings. They appear to have a more chronic form of P. falciparum malaria infection, were profoundly anaemic at presentation, showed gross dyserythropoietic changes in their bone marrows, and had a full reticulocyte response and rise in haemoglobin after treatment. A third group of children were encountered whose haematological abnormalities were intermediate to those of the acute and chronic groups. These findings indicate that the patho-physiological mechanisms responsible for the anaemia of P. falciparum malaria are different at different stages of the illness.

Electron microscope and high resolution autoradiographic studies of the erythroblasts in haemoglobin H disease

Electron microscope studies of bone marrow from a patient with haemoglobin H (HbH) disease have revealed the presence of highly condensed branching intracytoplasmic inclusions within a proportion of the early and late polychromatic erythroblasts and reticulocytes. Intraerythroblastic inclusions of this type have not yet been described in any other haematological disorder and may well be a specific feature of HbH disease. Electron microscope autoradiographic studies of the marrow cells from the patient with HbH disease revealed that (1) active protein synthesis continues in inclusion-containing erythroblasts and (2) there is a rapid precipitation of a considerable proportion of the newly synthesized free beta chains onto the surfaces of preformed inclusions, presumably after conversion to HbH. These electron microscope and electron microscope autoradiographic findings are quite different from the findings previously reported in homozygous beta thalassaemia using the same techniques.

Evidence for an immunological relationship between Streptococcus mutans and human cardiac tissue

Two-dimensional immunoelectrophoresis, indirect immunofluorescence, and radioimmunoassay were used to demonstrate that antisera from rabbits immunized with some strains of Streptococcus mutans contain antibodies that cross-react with human cardiac tissue. These rabbits were sensitized to a shocking dose of human heart antigen, and anaphylactic deaths were sometimes produced. Myocarditis was also a result of the immunization procedure. Data obtained with all five techniques were comparable. Cross-reactivity could be associated with three antigens designated ID, IF, and HL. Antigens ID and IF were major immunogens of S. mutans Ingbritt, but HL antibodies were produced only after hyperimmunization. Corss-reactivity was of an immunological nature and not the result of nonspecific factors such as bacterial Fc reactive components or antibody elicited to growth medium constituents. These findings support the hypothesis that immunization with S. mutans can induce autoimmune reactions and indicate that antigens must be selected with caution before formulating any dental caries vaccine.

Prevalence of high (3S)-3-hydroxyquinidine/quinidine ratios in serum, and clearance of quinidine in cardiac patients with age

In the sera from 42 patients receiving quinidine, (3S)-3-hydroxyquinidine (3-OH), an active metabolite of quinidine, and quinidine were determined by high-pressure liquid chromatography with fluorescence detection. These results were added to those of 25 other patients reported previously. The 3-OH/quinidine ratio averaged 0.34 +/- 0.17 (SD) with a range of 0.10 to 0.90. Eleven patients (16%) had ratios above 0.50. After adjusting for protein binding differences between the 2 compounds, these 16% had 3-OH concentrations in serum water greater than that of quinidine. An additional 7 patients (10%) of the total) had levels of this metabolite in serum water slightly less than that of quinidine. A histogram showing the frequency distribution of 3-OH/quinidine in serum indicates extensive skewing with possibly a bimodal distribution with the antimode at 0.50. Thus, 3-OH may make a significant contribution to the effect of quinidine therapy in a fraction of treated patients. The clearance of quinidine decreased with age, indicating the need for, on the average, higher doses of quinidine in the young.

Radioimmunoassay of class-specific antibodies to Streptococcus mutans in monkey serum and saliva

A radioimmunoassay (RIA) has been developed to measure class-specific antibodies to Steptococcus mutans in the serum and saliva of monkeys (Macaca fascicularis). Anti-human immunoglobulin antibodies purified by affinity chromatography on immobilised monkey immunoglobulins and labelled with 125I were employed. Formolised cells of S. mutans and an extract of culture supernatant adsorbed to polystyrene wells were used as solid-phase antigens. The coefficients of variation for IgG, IgA and IgM assays were less than or equal to 10% for both antigen systems. Two monkeys were immunised with formolised cells of S. mutans by subcutaneous injection and subsequent instillation of bacterial cells into their right parotid ducts. IgG, IgA and IgM antibody responses to S. mutans in samples of serum and saliva were quantitated by RIA. Immobilisation of purified components of S. mutans on polystyrene wells enabled the measurement of antibody response to a number of antigens to be made. The RIA is a sensitive, reproducible and quantitative method of measuring serum and salivary antibody responses in monkeys.

Heart-rate correlates of childhood activities: play, exploration, problem-solving and day-dreaming

Heart-rate was monitored while children were engaged in different activities. The first study examined the hypothesis that the behavioural distinction between exploration and play would be supported by the psychophysiological measure. Two-year-olds showed suppression of heart rate variability (HRV) during exploration, and even more during solution of a puzzle, suggesting that the task demands these two activities were greater than those during play. The second study demonstrated a relationship between HRV during daydreaming and during problem solving in 9-year-old children which was similar to that obtained between play and problem solving in younger children. The correlative use of HRV thus strengthened functional interpretations of behaviour.

Intracellular localization of 55Fe after serum-mediated uptake by human erythropoietic cells

Marrow cells of 3 patients with normoblastic erythropoiesis and 1 with sideroblastic erythropoiesis were incubated with serum-bound 55Fe Cl3 and studied by the technique of electron microscope autoradiography. In the 3 normoblastic marrows, both the mean grain counts and the percentages of grains situated over the cytoplasm (excluding the mitochondria) were higher in the early erythroblasts than in the intermediate and late erythroblasts. The percentages of autoradiographic grains situated over the mitochondria of early intermediate and late erythroblasts were 11.9-27.4, 56.5-61.1 and 65.3-65.9, respectively. Although the mean grain counts over these three cell classes in the sideroblastic marrow were similar to those in the normoblastic marrows, the proportions of grains over the mitochondria were higher, particularly in the early erythroblasts. In all 4 cases (1) some grains were situated at the junction between heterochromatin and euchromatin and (2) a few of the 55Fe-labelled immature-looking cells did not display the ultrastructural features usually attributed to pronormoblasts.

Acromegaly due to production of a growth hormone releasing factor by a bronchial carcinoid tumor

We have studied growth hormone production in a patient with a bronchial carcinoid and acromegaly. The absence of growth hormone from the carcinoid tumour was demonstrated by extraction, cell culture and immunoperosidase techniques. Using a linked perfusion culture system, effluent from the bronchial carcinoid tumour culture stimulated a rapid release of growth hormone from a rat pituitary monolayer. This is the first time evidence of growth hormone releasing activity by a bronchial carcinoid has been demonstrated in a production.

Electron microscope autoradiographic studies of the erythroblasts of a case of congenital dyserythropoietic anaemia, type II

The bone marrow cells of a patient with congenital dyserythropoietic anaemia, type II, were incubated with 3H-thymidine, 3H-uridine or 3H-leucine for 1 h and studied using the technique of electron microscope autoradiography. Several of the erythroblasts which either displayed the characteristic subsurface double membranes or showed various non-specific abnormalities of the nuclear membrane were found to be actively engaged in DNA, RNA and protein synthesis. Both members of some pairs of erythroblasts which were joined together by a spindle bridge were found to be engaged in DNA synthesis, indicating that some spindle bridges persist for a period longer than the duration of the G1 phase. A small proportion of mononucleate and binucleate late (non-dividing) erythroblasts showed a marked depression or arrest of protein synthesis and some or all of such cells were presumably destined to be phagocytosed by the bone marrow macrophages.

Strain related infectivity of Neisseria gonorrhoeae for the guinea-pig subcutaneous chamber and the variability of the immune resistance in different breeds of guinea-pig

The ability of gonococci to infect the subcutaneous chamber in guinea-pigs is strictly strain related. This ability was usually present in prototrophic strains and auxotrophs requiring proline only which were obtained from patients with uncomplicated gonorrhoea, but it was invariably absent in Neisseria gonorrhoeae auxotypes requiring arginine, uracil, and hypoxanthine, or arginine only for growth. All the strains obtained from disseminated gonococcal infections (all dependent upon arginine, uracil, and hypoxanthine) were unable to infect the guinea-pig chamber. Hence, the high invasiveness of N. gonorrhoeae for man and its infectivity for guinea-pig chambers appear to be unrelated properties. Although guinea-pigs of the same origin (Dunkin-Hartley) were used throughout, the degree of immune resistance was found to differ between the lines supplied by various breeders--that is, after a standard immunisation schedule using whole cell gonococcal vaccines, the homologous immune resistance to challenge varied from weak or non-existent in some lines, to highly resistant in others.

Capacity of ringed sideroblasts to synthesize nucleic acids and protein in patients with primary acquired sideroblastic anaemia

Bone marrow cells from two patients with primary acquired sideroblastic anaemia were studied using the technique of electron microscope autoradiography. Whereas a significant proportion of erythroblasts containing small to moderate quantities of intramitochondrial deposits incorporated [3H]thymidine into DNA, the majority of cells containing large quantities of intramitochondrial deposits did not. These results are consistent with the idea that several of the early polychromatic cells with large quantities of deposits become arrested in their progress through the cell cycle. The data also revealed that the accumulation of increasing quantities of iron-containing material within the mitochondria of an erythroblast was frequently (but not invariably) associated with and was possibly responsible for (I) a depression of RNA synthesis and (2) a more marked depression of protein synthesis. A small proportion of the erythroblasts showing a depression of protein synthesis also displayed various non-specific ultrastructural abnormalities indicative of cellular injury such as the presence of intranuclear clefts, nuclear membrane-associated myelin figures and lipid-laden intracytoplasmic vacuoles.

High resolution autoradiographic studies of RNA, protein and DNA synthesis during human eosinophil granulocytopoiesis: evidence for the presence of RNA on or within eosinophil granules

Human bone marrow cells which had been incubated with [3H]uridine or [3H]leucine for I h were studied using the technique of electron microscope-autoradiography. The autoradiographs revealed the presence of newly-synthesized RNA and protein molecules within or on a proportion of (I) the primary and secondary granules in all classes of eosinophil precursors and (2) the secondary granules in eosinophil granulocytes. It is suggested that the granule-associated RNA molecules may be concerned with the synthesis of at least some of the new protein molecules which were incorporated into the limiting membrane or substance of eosinophil granules long after the immature primary granule stage. Studies of eosinophil precursors which had been incubated with [3H]thymidine for I h showed that the eosinophil granules do not label with this DNA precursor.

Some features of bone marrow macrophages in patients with homozygous beta-thalassaemia

The bone marrow macrophages of patients with homozygous beta-thalassaemia were frequently situated adjacent to collagen fibres and sometimes formed intrasinusoidal cytoplasmic protrusions. They also appeared to phagocytose processes of erythroblast cytoplasm (at times containing precipitated alpha-chains) which projected into them from neighbouring erythroblasts. The cytoplasm of the macrophages included large numbers of heavily-iron-loaded secondary lysosomes of various sizes and shapes in addition to phagocytosed erythroblasts, erythrocytes and extruded erythroblast nuclei. Numerous ferritin molecules were found in the cytoplasmic matrix but there were hardly any in the mitochondria, endoplasmic reticulum or golgi saccules. A small number of ferritin molecules were present within the nucleus. Electron microscope autoradiographs of marrow fragments which had been incubated with [3H]leucine for 1 h revealed the presence of newly-synthesized protein molecules in all types of secondary lysosomes. Light microscope autoradiographs showed the [3H]thymidine labelling index of the bone marrow macrophages was less than 1% and suggested that only a very small proportion of these cells were actively preparing for division.

Glenohumeral joint replacement and postoperative rehabilitation

Prosthetic replacement of the humeral head in patients with severe fractures that detach or crush the articular surface and in patients with glenohumeral arthritis has been done at the Columbia-Presbyterian Medical Center since 1953. Recently, a revised prosthesis for the articular surface of the head of the humerus has been used in combination with a polyethylene glenoid component. This method of total shoulder replacement has been used in patients with rheumatoid arthritis and in other conditions where the glenoid fossa is abnormal. Postoperative physical therapy management is especially important in this unique joint and is explained in detail.

Treatment planning with a graphics tablet

A graphics-tablet treatment planning system is described. The cost effectiveness of this approach is especially attractive where time-sharing use of a central computer facility is available.