Depression of lymphocyte response to phytohaemagglutinin in the presence of plasma from children with acute protein energy malnutrition.

Phytohaemagglutinin-induced lymphocyte transformation of four healthy adults and a child with kwashiorkor was performed in the presence of plasma from nineteen patients with protein energy malnutrition and a nutritionally normal child. Marked inhibition occurred in the presence of plasma from six patients who subsequently died, moderate inhibition occurred in six other patients in the acute stage and in two of these six in the convalescent stage, whilst in the remaining seven there was no effect. Reduction in response did not appear to be due to plasma cytotoxicity. Plasma factors in some cases of malnutrition, associated with certain infections appear to inhibit the lymphocyte response and this may have prognostic implications.     

Psychosocial factors in medical and psychological treatment avoidance: the role of the doctor-patient relationship

A community sample of 1106 adults was examined to assess the impact of the doctor-patient relationship on participants' avoidance of treatment for a recognized medical or psychological problem. Of five aspects of participants' previous experience with their physicians, all but waiting time predicted participants' self-reported treatment avoidance. In two logistic regression models participants who felt their physicians listened more to their concerns were less likely to avoid treatment for both medical and psychological problems during the previous 12 months. These findings suggest that patients' perceptions of how they are treated by physicians may help explain why many people delay or avoid healthcare treatment, even when faced with a significant health problem.     

Crosslink formation in porcine valves stabilized by dye-mediated photooxidation

Bovine pericardial and porcine valve materials stabilized by dye-mediated photooxidation have shown potential for bioprosthetic valve use. Previously, in vitro and in vivo stability of these materials was demonstrated through enzymatic, chemical, extraction, rat subcutaneous, and functional challenges. Here, we examine the stability of photooxidized porcine aortic valves through amino acid, crosslink, and hydrothermal isometric tension analysis. Photooxidation reduced intact histidine residues from 17.0 to 0 residues per 1000, indicating the photooxidative alteration of this amino acid. Diphenyl borinic acid-derivitized hydrolyzates of proteins were separated by high-performance liquid chromatography, which identified several amino acid crosslinks that appeared with photooxidation that were absent in untreated controls. Thermal relaxation analysis indicated a significantly higher (p < 0.0002) thermal stability for photooxidized porcine cusps than that of untreated controls, with mean relaxation times for untreated cusps of 14,000 +/- 4650 versus 22,900 +/- 2480 s for photooxidized cusps. In summary, porcine aortic valve tissue treated by dye-mediated photooxidation contains new chemical species and exhibits properties consistent with intermolecular crosslink formation, which explain the increased biostability of this material and its potential for use in bioprosthetic devices.     

Abnormal IL-2 receptor levels in non-pregnant women with a history of recurrent miscarriage

BACKGROUND: Immunological abnormalities have been found in pregnant women with a history of recurrent miscarriage. This study compared interleukin-2 receptor (IL-2R) levels in non-pregnant women with a history of recurrent miscarriage with those found in serum from a non-pregnant group with no such history. METHODS: Group 1 comprised 49 non-pregnant women with a history of recurrent miscarriage (at least three consecutive miscarriages). Group 2 comprised 22 non-pregnant women with no history of miscarriage. Serum IL-2R levels were measured in all patients. RESULTS: The results obtained showed that although all women were not pregnant at the time of sampling, IL-2R levels were significantly higher in women in Group 1 compared with those in Group 2 (1589 +/- 1289 versus 1082 +/- 823 pg/ml; P < 0.05). Follow-up data were available for 21 women from Group 1. The next pregnancy ended successfully for 14 of these women, while seven miscarried again. The IL-2R levels obtained pre-pregnancy were not significantly different between the two groups (1480 +/- 910 versus 1356 +/- 716 pg/ml). CONCLUSION: This study has shown that non-pregnant women with a history of recurrent miscarriage have raised IL-2R levels. These increased pre-pregnancy IL-2R levels did not necessarily predict miscarriage for the next pregnancy.     

Categorization of clinical isolates of Helicobacter pylori on the basis of restriction digest analyses of polymerase chain reaction-amplified ureC genes.

Restriction endonuclease analyses of a 1.1-kb polymerase chain reaction-amplified portion of the ureC gene from Helicobacter pylori were used to group or to differentiate 21 clinical isolates. Isolates were placed into 4 groups after HindIII digestion alone, and placement was expanded into 15 groups after isolates were digested with AluI and PvuI.     

Effect of subthreshold voltage-dependent conductances on the transfer function of branched excitable cells and the conduction of synaptic potentials

1. Impulse response functions were determined from complex point impedance and transfer functions from cultured NG-108 cells to simulate the propagation of a synaptic potential in response to the release of transmitter. In general, the flow of synaptic current has a much shorter duration than the normal membrane time constant, thereby making the use of impulse response functions useful approximations to synaptic events. 2. The resonance observed during the activation of the potassium conductance was reflected in the impulse response function as a pronounced damped oscillation. A comparison of the impulse response functions calculated from point impedance and transfer functions showed similar results for current injections in the growth cone. 3. In addition to the resonance effects of the voltage-dependent conductances on transfer and impulse response functions due principally to the activation of conductances for outward currents, transfer functions were measured during the activation of a steady-state negative conductance. Under these conditions the phase function approaches 180 degrees, indicating that the voltage response is out of phase with the current. 4. In the steady state, the effect of a negative conductance is to algebraically add to the positive conductances and generally decrease the absolute conductance unless there is a net negative current. The decreased conductance enhances the impulse response and the DC space constant, thus leading to a better propagation of slow potentials. This effect can be seen as a decrease in the electrotonic length, L, with intermediate depolarizations. At large depolarizations the steady-state activation of the K conductance generally dominates and leads to a greatly increased electrotonic length. 5. Both the net conductances and the associated kinetics play a role in shaping the potential changes during a synaptic current. This is especially critical if there is a net negative steady-state conductance. Under these conditions there is a surprising reduction in the impulse response function. 6. Thus, during a subthreshold activation of the voltage-dependent negative conductances, the observable synaptic potentials would be either large potential responses due to an apparent increase in the impedance (algebraic summation of positive and negative conductances with a net positive conductance) or a minimal response because of the phasic cancellation due to a net negative conductance. The latter condition could exist near the synaptic reversal potential due to a large synaptic drive and would appear experimentally as a form of inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)