Prognostic importance of hypodiploid hemopoietic precursors in myelodysplastic syndromes

It has been suggested that a poor prognosis and the development of leukemia in patients with myelodysplasia may be related to chromosomal abnormalities. We measured the DNA content of bone marrow cells with flow cytometry in 19 hematologically normal subjects and in 70 patients who had recently been diagnosed as having myelodysplasia. Thirty-four of the patients were found to have aneuploidy. This was not related to the percentage of blast cells in the bone marrow, and there was no demarcation in terms of DNA content between patients with a high percentage of blast cells and those with a low percentage of such cells. Patients with hypodiploid marrow cells had a significantly shorter survival time than other patients (P = 0.001). Patients with hyperdiploid marrow and those whose marrow had a normal DNA content had similar survival times. Hypodiploidy appears to be a better indicator of poor survival than the marrow blast-cell count. Patients with sideroblastic anemia invariably had cells with a normal or high DNA content; none of these patients died during the study. Our data suggest that there is a relation between the loss of chromosomal material and progression toward a leukemic phenotype. It is tempting to speculate that this process may involve a loss of negative regulatory genes ("anti-oncogenes").

Non-cholinergic transmission in a sympathetic ganglion of the guinea-pig elicited by colon distension

Sensory transmission from the colon was studied using a preparation of inferior mesenteric ganglion (i.m.g.) attached to a segment of distal colon in guinea-pigs, in vitro. Electrical responses to colon distension were recorded intracellularly from neurones of the i.m.g. Distension of the distal colon up to an intraluminal pressure of 20 cmH2O caused an increase in resting asynchronous synaptic activity and a concomitant slow depolarization. The asynchronous synaptic activity, but not the slow depolarization, was abolished by cholinergic antagonists. Distension-induced non-cholinergic depolarizations were elicited in 44% of i.m.g. neurons sampled. For distensions of 1 min at 10-20 cmH2O, depolarizations reached a mean amplitude of 3.4 +/- 0.3 mV and lasted 108 +/- 7 s. Continuous distension resulted in a tachyphylaxis of the depolarization. Tetrodotoxin (3 X 10(-7) M) superfused over the i.m.g. reversibly abolished the distension-induced non-cholinergic depolarization. Distension-induced non-cholinergic depolarizations were accompanied by an increase in input resistance of 21%. Neuronal excitability also increased, as sub-threshold potentials produced by intracellular current injection reached threshold for firing action potentials during colon distension. The amplitude of non-cholinergic depolarizations increased with colonic intraluminal pressure between 2 and 20 cmH2O, although the slope of the mean amplitude-pressure curve decreased progressively at higher pressures. The amplitude of distension-induced non-cholinergic depolarizations increased as membrane potential was manually hyperpolarized to approximately -80 mV, whereupon further hyperpolarization resulted in a decrease in response amplitude. Non-cholinergic slow excitatory post-synaptic potentials (e.p.s.p.s) evoked by repetitive presynaptic nerve stimulation were reversibly attenuated by 19 +/- 8% during depolarizations produced by distension. Systemic administration of capsaicin (50-350 mg/kg) reduced the number of i.m.g. neurones exhibiting the non-cholinergic mechanosensory response; direct superfusion of capsaicin over the i.m.g. attenuated the response in some neurones but had no effect in others. These results demonstrate the existence of a non-cholinergic mechanosensory pathway from the colon to the i.m.g., and suggest that non-cholinergic transmission in the ganglion participates in mediating gastrointestinal reflexes. One transmitter utilized by the non-cholinergic mechanosensory pathway may be substance P.

Fast and slow synaptic potentials produced in a mammalian sympathetic ganglion by colon distension

Radial distension of the large intestine produced a slow depolarization in a population of neurons in the inferior mesenteric ganglion of the guinea pig. The slow potentials often occurred simultaneously with cholinergic fast potentials [( excitatory postsynaptic potentials (EPSPs]) yet persisted in the presence of nicotinic and muscarinic cholinergic antagonists when all fast EPSPs were absent. The amplitude of the distension-induced noncholinergic slow depolarization increased with increasing distension pressure. For distensions of 1-min duration at pressures of 10-20 cm of water, the mean depolarization amplitude was 3.4 mV. The slow depolarization was associated with an increase in membrane resistance, and prolonged periods of colon distension resulted in a tachyphylaxis of the depolarization. Desensitization of ganglion cells to the peptide substance P attenuated the distension-induced slow potential by an average of 49% +/- 17%. Thus, two colonic mechanosensory afferent pathways converge on principal ganglion cells in the inferior mesenteric ganglion: one was previously described to be mediated by acetylcholine, and the other is described here, whose transmitter remains to be determined but which preliminary evidence suggests is mediated in part by substance P. The noncholinergic afferent pathway may enhance the intestinal inhibitory reflex mediated by cholinergic mechanosensory afferent input to the abdominal prevertebral sympathetic ganglia.

Mediator release during nasal provocation. A model to investigate the pathophysiology of rhinitis

The pathogenesis of rhinitis was investigated using a model of nasal provocation with different types of stimuli. Allergic subjects had an immediate response to antigenic challenge with symptoms of rhinitis highly correlated with increments in the concentrations of histamine, prostaglandin D2, kinins and kininogens, leukotrienes, and toluene sulfonyl arginine methyl ester esterase activity in their nasal secretions. This reaction was abated by a tricyclic antihistamine also capable of inhibiting mediator release from human mast cells in vitro and, in some subjects, by disodium cromoglycate. In a number of patients, symptoms reappeared three to 12 hours after nasal provocation. This late reaction also involves release of all of the aforementioned mediators except for prostaglandin D2, and preliminary data suggest that it can be inhibited by oral or topical steroids. Cold, dry air can induce rhinitis with mast cell mediator release from selected subjects. The pathogenesis of this reaction is unclear, but there are indications that osmolarity changes are responsible for mast cell activation. Thus, mast cells can be induced to release mediators and cause nasal symptoms by both immunologic and physical mechanisms, which may account for the pathophysiology of several types of rhinitis.

Vasopressin-mediated slow EPSPs in a mammalian sympathetic ganglion

Vasopressin is one of numerous neuropeptides contained in sympathetic ganglia, but whose function remains unresolved. In this report, we present electrophysiological evidence that arginine-vasopressin (AVP) is a neurotransmitter in guinea pig inferior mesenteric ganglion (IMG). AVP superfused over the IMG, in vitro, produced in a population of neurons a membrane depolarization accompanied by a resistance increase, both of which were blocked by a specific V1 receptor antagonist. Moreover, slow excitatory postsynaptic potentials (EPSPs) elicited by repetitive nerve stimulation were attenuated in 75% of cells tested in the presence of excess AVP, and occasionally in the presence of the antagonist. Thus, AVP joins substance P as a putative transmitter of slow potentials in the guinea pig IMG.

A slow EPSP in mammalian inferior mesenteric ganglion persists after in vivo capsaicin

The non-cholinergic slow excitatory postsynaptic potential (EPSP) in the guinea pig inferior mesenteric ganglion (IMG) is believed to be mediated by substance P (SP). Yet, in ganglia of guinea pigs treated with capsaicin (50, 100, or 350 mg/kg, s.c.), a compound that depletes SP from sensory neurons, slow EPSPs were only 50% smaller in amplitude than those in vehicle-treated controls; this was true at all dosages. When ganglia from capsaicin-treated animals were desensitized to SP, slow EPSP amplitude was decreased by 50% from predesensitization values. These data indicate that capsaicin does not eliminate the slow EPSP in the IMG and suggest that both SP and another transmitter are involved in co-mediating this response.

Immunoperoxidase examination of cutaneous infiltrates of mycosis fungoides and large-plaque atrophic parapsoriasis with OKT10

A monoclonal antibody (OKT10), which was developed recently, reacts with pro-thymocytes, T cell acute lymphoblastic leukemia (ALL) cells, cells in normal bone marrow (including plasma cells), and activated T cells. Tissues from patients with cutaneous T cell lymphoma were studied for the presence of OKT10-reactive cells with the use of an indirect immunoperoxidase technic. OKT10-reactive cells were identified in three of eight cases of mycosis fungoides, one of two cases of Sézary syndrome, with an equivocal reaction in one of ten cases of large-plaque parapsoriasis and in one of seven positive patch tests (allergic contact dermatitis). The biologic and possible clinical implications are discussed.

Minor physical anomalies and behavior in children: a review

The recent literature concerning minor physical anomalies (MPA) and their relation to behavior is reviewed. Research seems to indicate that for males there is considerable consistency in the results but the finding with females is tenuous at best. It appears that a high number of MPA are evident in several pathological groups of boys, as compared with normal controls. In addition, there is a suggestion that MPA are correlated with severity of hyperactivity, IQ, and school achievement. Furthermore, there is also a relationship between a high number of MPA and obstetrical complications. The etiology of MPA and their utility in predicting pathological behavior is discussed.

Recurrent abdominal pain: a psychogenic disorder?

A controlled study of 30 children with recurrent abdominal pain and 30 pain free children failed to show any statistically significant differences between the groups on a variety of psychological variables thought to be associated with psychogenicity. A psychogenic basis has often been assumed as the cause in diagnosis of recurrent abdominal pain when clinical examination and laboratory tests show no organic or medical reason. We emphasise that establishing a psychogenic cause is only indicated where there is positive evidence for psychological factors such as family or school stress, extreme personality characteristics, or modelling of family pain behaviour.

Differing effects of pectin, cellulose and lignin on stool pH, transit time and weight

Randomized cross-over studies were undertaken to determine the effects of daily dietary supplements of pectin (12 g/d), cellulose (15 g/d) and lignin (12 g/d) on stool characteristics of healthy volunteers. Detailed dietary records were kept throughout the study. Stool collections over 48 h were used to determine mean stool pH and weight. The single stool transit time was measured using radio-opaque markers. Pectin did not significantly alter the mean stool pH, transit time or 24 h wet weight. Cellulose lowered the mean stool pH from 6.38 to 6.12, decreased mean stool transit time by 27% and increased mean wet stool weight by 57%. Lignin lowered the mean pH from 6.34 to 6.25, decreased the stool transit time by 20% and increased stool weight by 27% but these changes were not statistically significant. These findings have shown that individual fibre components have different colonic metabolic effects and support the view that associations between dietary fibre intakes and diseases such as colorectal cancer should be evaluated with regard to the type of fibre components consumed.

OKT 9 reactivity in mycosis fungoides and large plaque (atrophic) parapsoriasis

A monoclonal antibody OKT 9 which detects a determinant expressed by a variety of proliferating cell types has been recently developed. This antibody was used in conjunction with the immunoperoxidase technique to study the cutaneous lymphoid infiltrates of nine patients with mycosis fungoides, one patient with lymphomatoid papulosis, two patients with Sézary syndrome, and ten patients with large plaque atrophic parapsoriasis (a condition which may terminate in overt mycosis fungoides.) OKT 9 reactive cells were identified in all cases of mycosis fungoides examined, in one case of lymphomatoid papulosis, one of two cases of Sézary syndrome, and one of ten cases of large plaque atrophic parapsoriasis. These results suggest that further studies using OKT 9 should be performed to assess whether OKT 9 reactivity may be used as a prognostic marker in cutaneous lymphomas and prelymphomas.