Biomedical subjects
Publications and source records attributed to M J Murphy.
The clinical and pathological findings in a patient with locked-in syndrome caused by a solitary pontine abscess are reported for the first time. Successful treatment of brainstem abscess rests on early and accurate diagnosis.
The role of potassium as an essential promotor of erythroid progenitor growth (BFU-e & CFU-e) from normal murine hematopoietic tissues was studied. Dialyzed fetal calf serum, over a wide range of concentrations, was shown to reduce the numbers of BFU-e and CFU-e that could be cultured from normal murine bone marrow. A dose-dependent addition of 1 M KC1 restored erythroid progenitor colony growth to the levels generally seen when normal, non-dialyzed fetal calf serum was used. Furthermore, when [K] was increased in some human urinary and sheep plasma erythropoietin preparations, the number of erythroid progenitor cells cultured also increased. This influence is crucial to the differentiation of committed stem cells into the erythroid pathway and must therefore be considered in the development of serum-free growth media.
1 The efficacy of labetalol in the treatment of severe hypertension (diastolic greater than or equal to 115 mm Hg) was studied retrospectively. Ten patients were followed for more than 6 months. At 6 months, eight were well controlled and the mean dose in those was 975 mg daily. Four of these were receiving labetalol alone; two were on labetalol and diuretic only. 2 Three patients were resistant to doses of 1600, 1800 and 2400 mg daily respectively; two of these were controlled with increased doses of vasodilator drugs. In two cases labetalol had produced large falls in the standing BP while not influencing the supine BP. 3 Three other resistant patients were seen, of whom one merely required an increase in dose to 2200 mg daily and the addition of a diuretic. Both the others were elderly, had severe vascular disease, and suffered disabling postural hypotension on a dose of labetalol which did not influence the supine BP. 4 Labetalol can control severe hypertension. There remain patients whose supine BP is not influenced by a dose of labetalol which produces marked postural hypotension.
Four patients with predominantly unilateral Parkinsonism are reported in whom involuntary movements in the affected limbs developed while on levodopa. Based on the known pathological and biochemical abnormalities underlying Parkinson's disease, it is suggested that these observations support the concept of denervation supersensitivity as the pathogenetic mechanism in the development of levodopa dyskinesias.
A procedure which provides more accuracy in the identification and scoring of in vitro derived erythroid colonies (i.e. BFU-e and CFU-e) from normal mouse and human marrow and spleen cells has been developed. Up to now identification of erythroid colonies has been based on staining with acidified benzidine which consistently displays "background staining" of granulocyte/macrophage colonies. The staining reaction with these reagents is such that identification of erythroid colonies is less than precise. The modified benzidine procedure described herein eliminates the staining reactivity of granulocyte/macrophage colonies and specifically reacts with only those cells that contain hemoglobin. Furthermore, individual colonies and/or cells may readily be counterstained and examined by high resolution light microscopy.
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In a patient presenting with the clinical features of normal pressure hydrocephalus, a membranous obstruction of the aqueduct of Sylvius was demonstrated by combined air encephalography and contrast ventriculography. Ventriculoatrial shunting resulted in clinical improvement without significant change in ventricular size.
Megakaryocytes and their precursor cells were sustained in mouse bone marrow suspension cultures for over 4-6 wk. Megakaryocyte precursor cells were detected by their capacity to form colonies of megakaryocytes in semisolid agar cultures. Colony formation was dependent on the presence of medium conditioned by a myelomonocytic leukemic cell line (WEHI-3CM). Megakaryocytes from the liquid and semisolid cultures were identified by cytoplasmic acetylcholine esterase and by ultrastructural analysis. The suspension medium from the bone marrow liquid cultures which sustained megakaryopoiesis was not directly acitive in stimulating megakaryocyte colony formation in the semisolid agar cultures, but potentiated the number of colonies detected when WEHI-3CM was present. Bone marrow-conditioned medium increased the sensitivity of megakaryocyte progenitor cells to the stimulus in WEHI-3CM. Addition of the activities present in the two sources produced a quantitative assay for the detection of mouse megakaryocyte progenitor cells. These studies showed: (1) that no inductive regulator of in vitro clones of megakaryocytes was present in the supernatants from the long-term marrow cultures and, (2) that at least two factors were necessary for the induction of megakaryocyte progenitors to proliferate and differentiate in semisolid cultures in vitro.
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Sirohaem is a new type of haem that has been detected as a prosthetic group of several bacterial and plant enzymes that catalyse the six-electron reductions of sulphite to sulphide or of nitrite to NH(3). When a methionine-requiring mutant of Escherichia coli K12 was grown on a minimal medium supplemented with d-glucose and l-[Me-(3)H]methionine, 2.4 methyl groups per spectrophotometrically detectable haem group were incorporated into the sirohaem prosthetic group of the NADPH-sulphite reductase isolated from the organism. When the same strain of cells was grown on minimal medium supplemented with d-[U-(14)C]glucose and l-[Me-(3)H]methionine, the sirohaem isolated was found to contain a ratio of glucose-derived carbon/methionine-derived methyl of 19.8. This ratio is in excellent agreement with the value of 20 predicted by the iron-dimethyl-urotetrahydroporphyrin structure for sirohaem proposed by Murphy, Siegel, Kamin & Rosenthal [(1973) J. Biol. Chem.248, 2801-2814]. It can be concluded that sirohaem is indeed methylated, with the methyl groups derived from methionine (rather than by modification of existing side chains, as in protohaem). The structure proposed by Murphy et al. (1973) is therefore probably correct in its essential features. A possible relationship between the pathway for biosynthesis of sirohaem and that for synthesis of vitamin B(12) is discussed.
BCNU,N,N1-bis(2-chloroethyl)-N-nitrosourea is known to produce 3-hydroxyethylcytidine and 3,N4-ethanocytidine when it reacts with polycytidylic acid. The nucleoside, 3,N4-ethanocytidine, presumably results from cyclization of 3-chloroethylcytidine formed initially by transfer of chloroethyl carboniumions from BCNU to cytidine. In order to study the significance of this unusual derivative, we have synthesized 3,N4-ethanocytidine and converted it to the corresponding 5'-mono- and diphosphates. 3,N4-Ethanocytidine diphosphate has been successfully converted to a high molecular weight polymer.
Saccadic and smooth eye movements are controlled by separate mechanisms within the nervous system. We describe a patient with familial ataxia, considered to be a form of olivopontocerebellar degeneration, who is incapable of generating reflex or voluntary saccades. She can, however, move her eyes smoothly to the normal limits of lateral gaze, even when her head is prevented from moving. Latency before onset of movement is prolonged, and the velocity of movement is abnormally slow. We postulate that the degenerative process may have affected selectively those cells of the ventral paramedian pontine tegmentum responsible for the generation of saccades; and the the prolonged latency from presentation of a visual stimulus to the onset of movement is related to an inability to generate burst discharges needed to overcome the viscoelastic properties of the orbital tissues.
Five to ten per cent of the cells in lymph draining renal allografts in sheep have the morphology of mononuclear phagocytes (MNP). These cells have been examined by light and electron microscopy and their functional characteristics investigated. The vast majority of MNP were of recipient origin. Their traffic increased from about 10(6)/hr immediately after grafting to between 2 and 4 X 10(7)/hr just prior to rejection. During the 1st 2 to 3 days, the majority of MNP had the morphology of monocytes, but the proportion of mature macrophages increased steadily to 30%. During the later stages, many of these large macrophages showed features of activation in terms of their spreading and phagocytic capacities. No NDA synthesis was observed in MNP until the latest stages, when a small proportion (less than 1%) of MNP labelled in vitro. Short-term cultures of lymph cells from kidneys undergoing rejection gave rise to numerous giant cells. It is suggested that there is continual traffic of MNP through the grafted kidney and that a proportion of MNP differentiate within the kidney and show features of activation.
Growth of human erythroid cells in soft-agar culture with no added erythropoietin was demonstrated. This growth was particularly marked in patients with diseases such as myelofibrosis (MF) in which patients had a previous history of polycythaemia vera (PV) characterized by excessive red cell production. A rapid assessment of the proportion of erythroid colonies was obtained by directly staining the culture with benzidine. Fixed and stained preparations of these agar-grown cells revealed elements in all stages of erythroid maturation. The morphology of these erythroid colonies was characteristic of 'erythroblastic islands' containing central, iron-containing macrophages, surrounded by erythrocytic precursors, with the more mature erythrocytes found at the periphery of the colony. These observations document that erythropoiesis may be maintained in agar cultures, and suggest that this technique may be of diagnostic value in disease states characterized by abnormalities of red cell production.
Pneumocystis carinii was propagated in vitro with primary embryonic chick epithelial lung (CEL) cells. Viability and growth of the organism were demonstrated by direct observation of the reproductive cycle in the Sykes-Moore chamber, serial passage with an increase in the number of mature cysts forms, the cytopathic effect of the organism on cell culture, and inhibition of growth of the organism by specific antiserum and pentamidine isethionate. Attempts to culture P. carinii indefinitely were not successful. However, cyst forms derived from murine and human sources increased 100-fold and 10-fold, respectively, during CEL cell culture passages. Serial passage of trophozoites alone resulted in the development of typical CPE and a maximum number of 2.8 X 10(3) cyst forms. Autoradiographic methods demonstrated active DNA, RNA, and protein synthesis within the cyst and suggest that metabolic interaction between the host cells and the organisms occurred. The nature of the attachment of P. carinii to the host CEL cell was clearly discernible by scanning electron microscopy (SEM). In the reproductive cycle a vegetative cell (designated "trophozoite") attached by tubular expansions to the hhed without entering the cell. Sporozoites developed within the detached young cyst, reaching a maximum number of eight within the mature cyst. Excystment occurred through single or multiple sites in the cyst wall, after which the released trophozoite attached to a new host cell.
Pneumocystis carinii is a parasitic microorganism which induces an often fatal pneumonitis in a variety of compromised patients (e.g., premature infants, those with congenital immune deficiency disorders, those therapeutically immune suppressed, etc.). Organisms derived from murine sources were cultivated in vitro on monolayers of primary embryonic chick epithelial lung cells. The infected cultures were then examined by scanning electron microscopy. An examination of the surface ultrastructure revealed pleomorphic organisms which were not only attached to host cells with anchoring fibers but also connected to other parasites via fine fibrils. Another type of fine fibril was observed which may play a role in the organism's nutrition.
Spontaneously flowing fistulae were established in the efferent lymphatics of popliteal, prescapular and prefemoral nodes and lumbar trunk or in the afferent lymphatics draining the kidney and liver of sheep. Lymph was collected from these sites over various time intervals and assayed for erythropoietin (Ep) content. The objective of the study was to establish the anatomic site(s) of Ep production. Normal lymph did not contain detectable titers of Ep, nor did renal lymph or blood plasma from a sheep systematically treated with cobaltous chloride. Renal lymph did contain measurable levels of Ep following renal artery constriction, unilateral hydronephrosis or phenylhydrazine-induced hemolytic anemia. Phenylhydrazine treatment also produced elevated Ep levels in lymph from the liver but not in lymph efferent from either popliteal or prescapular nodes. These results indicate that Ep is generated primarily in the kidney and that the liver may be an extrarenal source of the hormone. The surgical techniques used in this study offer distinct advantages in examining the composition and physiology of lymph in sheep.
The collision technique was used to study the incidence of anastomosis between median and ulnar nerves in the forearm (Martin-Gruber anastomosis). A motor anastomosis from median to ulnar nerve was found in 57 (17%) of 328 unselected subjects. The anomaly was bilateral in 39 subjects (68%) and unilateral in 18, nine on the right and nine on the left. Both hypothenar and thenar muscles were tested in 77 of 96 hands with the anastomosis (right and left sides combined). Both muscle groups were innervated by the communicating fibers in 63 hands (82%). Anomalous innervation was limited to hypothenar muscles in 13 and to thenar muscles in one hand. In contrast to the high incidence of the anastomosis from median to ulnar nerve, crossover from ulnar to median nerve in the forearm was found in none of 303 subjects tested.