Relationship of OKT3 sensitization and vascular rejection in cardiac transplant patients receiving OKT3 rejection prophylaxis

We prospectively and serially monitored plasma levels of OKT3 in 20 patients who were receiving 14- or 21-day rejection prophylaxis with OKT3. We retrospectively compared plasma OKT3 levels with biopsy scores assessed by light microscopy and immunofluorescence, clinical findings, human antimouse antibody (HAMA) production assessed by a blocking assay and by ELISA, and circulating immune complex levels assessed by a flow cytometric Raji cell assay. Using these methods, we evaluated the relationship of OKT3 sensitization, a humorally mediated immune response, to the development of vascular rejection in these patients. We found that 6 of 20 patients had declines in plasma OKT3 levels to less than 50% of their steady-state value before the conclusion of therapy (OKT3 consumption). This fall in plasma OKT3 preceded a significant rise in the CD 3 lymphocyte level by up to 3 days. All 6 patients showed HAMA production by either blocking or ELISA assay (P = less than 0.02) and developed vascular rather than cellular rejection (P = less than 0.01). OKT3 sensitization was significantly more common in patients treated with 21-day rejection prophylaxis (4 of 6 patients, P = less than 0.01). Only 4 of 14 other patients showed vascular rejection; 2 of these 4 also developed HAMA without OKT3 consumption and both had been treated with 21-day rejection prophylaxis with OKT3. None of the 20 patients showed significant levels of circulating immune complexes. This study demonstrates that OKT3 sensitization is strongly associated with vascular rejection. Vascular rejection was usually demonstrated 7 days after OKT3 consumption was seen and was coincident with HAMA production. By contrast, 4 patients without OKT3 sensitization had vascular rejection demonstrable in the early posttransplant period; in such patients, prospective immunofluorescence of biopsies was the only reliable indicator of this rejection type. The higher incidence of vascular rejection in these 20 patients was definitely related to the use of 21-day OKT3 rejection prophylaxis. Overall, 7 of the 12 patients treated with this regimen developed vascular rejection. Allograft and patient survival among patients with vascular rejection was significantly worse than in patients with cellular rejection (P = less than 0.01). Prospective monitoring of patients treated with OKT3 by serial plasma levels and by biopsy immunofluorescence will identify patients at risk for these types of humoral rejection.

Permeability of the blood-brain barrier to the immunosuppressive cyclic peptide cyclosporin A

Uptake of the immunosuppressive lipophilic peptide cyclosporin A has been measured by a number of techniques. The brain uptake index (BUI) technique in the rat yields only a small BUI value that is not significantly different from that of sucrose and mannitol and is comparable to other published BUI values for this compound. Brain perfusion studies in the guinea pig produce a unidirectional cerebrovascular permeability constant (Kin) of 1.2 +/- 0.28 microliter g-1 min-1 for the hippocampus. Intravenous bolus injection techniques also in the guinea pig characteristically produce a larger Kin value of 2.53 +/- 0.38 microliter g-1 min-1 for the same brain region, even after a correction for the inulin space of the tissue has been made. Apparent penetration of cyclosporin A into the cerebrospinal fluid (CSF) determined with the intravenous bolus injection technique is small with a Kin of 0.79 +/- 0.07 microliter g-1 min-1. However it is suggested that the radioactivity present in CSF is largely tritiated water. Studies with cultured cerebral endothelial cells from the rat have also been carried out and show that the cultured cells take up and accumulate cyclosporin A in vitro, achieving a tissue-to-medium ratio of 20 after 25 min of incubation. It is suggested that cyclosporin A is primarily taken up from lipoprotein at the blood-brain interface but, because of tight junctions at the blood-brain and blood-CSF barriers, becomes effectively trapped in the cerebral endothelial cells and the choroid plexus.

Creating a new drug service in Edinburgh

After one year Edinburgh's Community Drug Problem Service has shown that if psychiatric services offer consultation and regular support for drug users many general practitioners will share the care of such patients and prescribe for them, under contract conditions, whether the key worker is a community psychiatric nurse or a drug worker from a voluntary agency. This seems to apply whether the prescribing is part of a "harm reduction" strategy over a long period or whether it is a short period of methadone substitution treatment. Given the 50% prevalence of HIV infection among drug users in the Edinburgh area and the fact that only half of them have been tested for seropositivity, the health and care of this demanding group of young people with a chaotic lifestyle are better shared among primary care, community based drug workers, and specialist community drugs team than treated exclusively by a centralised hospital drug dependency unit. As the progression to AIDS is predictable in a larger proportion of drug users who are positive for HIV, there is an even greater need for coordinated care between specialists and community agencies in the near future.

Dual importance of positive charge in the C-terminal region of filamentous bacteriophage coat protein for membrane insertion and DNA-protein interaction in virus assembly

Gene VIII encoding the procoat protein of the Class II filamentous bacteriophage Pf1 (infecting Pseudomonas aeruginosa) has been cloned and expressed in Escherichia coli and subjected to site-directed mutagenesis. The two positively charged residues clustered near the C-terminus, arginine-44 and lysine-45, were systematically converted to uncharged residues and serine-41 was converted to an arginine residue. Removal of positive charge in the C-terminal region of the molecule seriously impaired the ability of the procoat molecule to undergo insertion at the E. coli cell inner membrane, as manifested by the diminished processing of the N-terminal leader peptide. The basic amino acids near the C-terminus of the coat protein are also involved in neutralizing the negatively charged viral DNA during virus assembly. However, despite its additional positive charge, the S41R mutant protein was unable to participate in the assembly of Class I bacteriophage fd in E. coli. This dual requirement of positively charged residues in the C-terminal region of the coat protein for membrane processing and insertion and for electrostatic neutralization of the encapsidated DNA poses important constraints on the evolution of filamentous bacteriophages with two different helical symmetries.

The transport of leucine and aminocyclopentanecarboxylate across the intact, energy-depleted rat blood-brain barrier

The transport across the blood-brain barrier of the large neutral amino acid leucine and the nonmetabolised aminocyclopentanecarboxylate (ACPC), of similar molecular size, was studied in the perfused, energy-depleted rat brain. It was found that when both leucine and ACPC were perfused for periods of up to 10 min their accumulation in the brain increased in a linear fashion. The ratio of perfusate radioactivity per milliliter and tissue radioactivity per gram (Rt/Rp) rose to above unity for both leucine and ACPC, indicating continued uptake against a concentration gradient of the radiolabel within the CNS. When the effect of increasing the concentration of the amino acid upon its influx into the brain was studied, it was found that under these conditions the kinetics of transport for both leucine and ACPC were of a similar order of magnitude to those reported previously in vivo. The values for the Michaelis constant for transport (Km), maximum rate of transport (Vmax), and the constant for the apparently linear, nonsaturable component (Kd) for leucine into the cerebrum were 84.5 +/- 29.0 microM, 45.5 +/- 1.5 nmole/min/g, and 2.62 +/- 0.15 microliters/min/g, respectively, and for ACPC 381 +/- 64 microM, 54.0 +/- 1.5 nmole/min/g and 0.35 +/- 0.10 microliter/min/g, respectively. Comparing this data with previously reported values it is suggested that the transport of leucine into the central nervous system from a perfusate or bolus where no other competing amino acids are present, is flow dependent. Furthermore, ACPC enters the brain almost entirely by a carrier-mediated process, with little or no nonsaturable influx despite a similar oil/water partition coefficient as leucine.

The effect of a low pH saline perfusate upon the integrity of the energy-depleted rat blood-brain barrier

The effect of a low pH perfusate upon the integrity of the rat blood-brain barrier was studied using an in situ supravital brain perfusion technique in which high-energy phosphates are depleted. Control animals were perfused for 10 min with a Ringer's salt solution containing the metabolic inhibitor 2,4-dinitrophenol (DNP) and adjusted to a pH of 7.4. In two separate experimental groups the perfusate, consisting of either the same medium as the controls or with additional buffering from Tris maleate, was switched after 5 min at a pH of 7.4, to a medium adjusted to pH 5.5 with lactic acid. Following a total perfusion time of 10 min, the integrity of the blood-brain barrier was assessed using the small molecular weight tracer [14C]mannitol. The cerebral perfusate flow rates (CPFR) after 10 min of perfusion were also determined in the three groups by perfusing for 40 s with [14C]iodoantipyrine. In each group, mannitol was excluded from the tissue of the brain to the same degree as has been previously reported in vivo, indicating an intact blood-brain barrier. There was also no significant pH-dependent change in CPFR. Ultrastructural examination of animals that had been perfusion fixed following in situ perfusion revealed no obvious differences between the cerebral endothelium of the control and low pH perfused animals. These results demonstrate that in the absence of energy-producing metabolism a perfusate pH of 5.5 is insufficient to disrupt the blood-brain barrier.

Characterization of cells comprising murine thymocyte multicellular complexes

Characterization of complexes between thymocytes and thymic stromal cells was facilitated in the present study by demonstrating that complexes would reform if cells were incubated for 1.5 to 2 h in vitro at ambient temperature. Several immunologic approaches were used to determine the phenotype of complexed cells. Bound T cells were 97% double-positive (CD4 and CD8), 3% double-negative and greater than 99% CD3 positive by using immunoperoxidase immunohistology on cytospins. Five percent expressed the TCR beta-chain and 1 to 2% were IL-2R positive. The percentages were the same whether complexes were preformed in vivo or formed in vitro. Despite the apparent absence of single positive cells in complexes, when isolated CD4 or CD8 positive cells were tested for their ability to bind to adherent thymic macrophages, each subpopulation contained some cells which were capable of complex formation. When thymocytes were fractionated by density, steroid sensitivity or peanut agglutinin positivity then allowed to form complexes, cells with an immature phenotype had a greater propensity for complex formation. Central stromal cells all were class II MHC gene product (I-A and I-E) positive, expressed macrophage-associated Ag (B23.1 and MAC-1), were negative for cytokeratin but positive for vimentin, were reactive with a polyclonal antimacrophage serum, but did not express dendritic cell Ag (33D1). The data demonstrate that immature thymocytes bind exclusively to class II MHC gene product positive thymic macrophages. This binding step may play a role in the acquisition of T cell function in the thymus.

Characterization of cells comprising murine thymocyte multicellular complexes

Characterization of complexes between thymocytes and thymic stromal cells was facilitated in the present study by demonstrating that complexes would reform if cells were incubated for 1.5 to 2 h in vitro at ambient temperature. Several immunologic approaches were used to determine the phenotype of complexed cells. Bound T cells were 97% double-positive (CD4 and CD8), 3% double-negative and greater than 99% CD3 positive by using immunoperoxidase immunohistology on cytospins. Five percent expressed the TCR beta-chain and 1 to 2% were IL-2R positive. The percentages were the same whether complexes were preformed in vivo or formed in vitro. Despite the apparent absence of single positive cells in complexes, when isolated CD4 or CD8 positive cells were tested for their ability to bind to adherent thymic macrophages, each subpopulation contained some cells which were capable of complex formation. When thymocytes were fractionated by density, steroid sensitivity or peanut agglutinin positivity then allowed to form complexes, cells with an immature phenotype had a greater propensity for complex formation. Central stromal cells all were class II MHC gene product (I-A and I-E) positive, expressed macrophage-associated Ag (B23.1 and MAC-1), were negative for cytokeratin but positive for vimentin, were reactive with a polyclonal antimacrophage serum, but did not express dendritic cell Ag (33D1). The data demonstrate that immature thymocytes bind exclusively to class II MHC gene product positive thymic macrophages. This binding step may play a role in the acquisition of T cell function in the thymus.

Dietary amino acid analogues and transport of lysine or valine across the blood-brain barrier in rats

Studies were undertaken to determine if dietary disproportions of amino acids would alter flux into brain of the amino acid present in the diet in a growth-limiting concentration. Rats were adapted to a lysine-limiting diet before receiving a meal of this control diet, alone or with added lysine or homoarginine (a competitor for lysine transport) or both, before intravenous infusion of [14C]lysine. The brain-to-plasma radioactivity ratio was lower in rats fed extra lysine or homoarginine than in rats fed the control diet, whereas lysine flux and brain lysine concentration were high in rats fed extra lysine alone. Flux and concentration were lower in rats fed homoarginine + lysine than in rats fed extra lysine alone. Other rats were fed a valine-limiting diet containing added valine, norleucine (a competitor for valine transport) or both, before [14C]valine was infused. Valine flux and brain valine concentrations were higher in rats fed extra valine than in control rats, whereas flux was lower in the group fed norleucine alone. Valine flux was higher in rats fed norleucine + valine than in the rats fed norleucine alone. Our studies show that dietary disproportions of amino acids can alter the flux of specific amino acids across the blood-brain barrier.

Hyperosmolar opening of the blood-brain barrier in the energy-depleted rat brain. Part 1. Permeability studies

A simple saline perfusion system was used to investigate the effects of hyperosmolar solutions of arabinose and mannitol upon the permeability of the blood-brain barrier. The small, polar molecule [14C]mannitol and the larger, visual marker Evans blue were used as indicators of barrier integrity in the perfused energy-depleted brain. One-minute perfusion of hyperosmolar solutions consistently opened the barrier suggesting that the mechanism of osmotic barrier opening is independent of energy-producing metabolism. The accumulation of radiolabel in the brain was expressed as the ratio of tissue to perfusate radioactivity (Rt/Rp) and, for cerebrum, this increased from a control value of 0.0022 +/- 0.0007 (mean +/- SEM; n = 4) to a value of 0.0124 +/- 0.0008 (n = 4) following 0.9 M arabinose and to 0.0495 +/- 0.0072 (n = 4) following 1.8 M arabinose. There was a significant reduction of water content of hyperosmolar perfused brains. These findings support the hypothesis that osmotic barrier opening is the result of the passive shrinkage of endothelial cells and the surrounding tissue.

Increased immunoglobulin response to gamma-interferon by lymphocytes from patients with systemic lupus erythematosus

The factors responsible for abnormal B-cell activation in systemic lupus erythematosus (SLE) are incompletely understood. This study tested the hypothesis that the abnormal B-cell activation observed in human SLE may be due to an augmented response to a helper signal. We demonstrated that non-T cells from 10 of 19 SLE patients increased IgG production in response to interferon-gamma (IFN-gamma) by a mean factor of 20.9 +/- 3.9 over resting levels, while controls stimulated a mean factor of 3.0 +/- 0.5 (P less than 0.005). We found no relationship of IFN-gamma responsiveness to disease activity. Serotyping for HLA A, B, C, and D loci suggested that the hyperresponsiveness may be genetically linked to HLA-Cw7. We conclude that IFN-gamma may contribute to the development and perpetuation of SLE in a subset of patients with SLE.

Threonine entry into rat brain after diet-induced changes in plasma amino acids

Passage of amino acids across the blood-brain barrier is modified by the amino acid composition of the blood. Because blood amino acid concentrations respond to changes in protein intake, we have examined associations among diet, plasma amino acid patterns, and the rate of entry of threonine into the brain. Rats were adapted for 8 h/day for 7-10 days to diets containing 6, 18, or 50% casein before receiving a single, independently varied, final meal of a diet containing 0, 6, 18, or 50% casein. After 4-7 h, they were anesthetized and infused intravenously with [14C]threonine for 5 min before plasma and brain samples were taken for determination of radioactivity and amino acid content. Plasma and brain threonine concentrations decreased as protein content increased in the diets to which the rats had been adapted. Plasma threonine concentrations increased twofold, from 1.6 to 3.0 mM, when rats adapted to 6% casein meals received a single 50% casein meal rather than a nonprotein meal; a fivefold increase, from 0.13 to 0.69 mM, occurred when rats had been previously adapted to 50% casein meals. Increasing the protein content of the final meal did not increase brain threonine concentrations. Highest and lowest rates of threonine entry into the brain occurred, respectively, in rats adapted to 6 and 50% casein meals. Changes in plasma threonine concentrations and threonine flux into brain reflected protein content of both pretreatment and final meals.

Valine entry into rat brain after diet-induced changes in plasma amino acids

Passage of amino acids across the blood-brain barrier is assumed to be modified by amino acid composition of the blood. To gain a better understanding of the effects of protein intake on brain amino acid uptake, we examined associations among diet, plasma amino acid patterns, and the rate of entry of valine into the brain. Rats were fed (8 h/day for 7-10 days) diets containing 6, 18, or 50% casein before receiving one meal of a diet containing 0, 6, 18, or 50% casein. After 4-7 h, they were anesthetized and infused intravenously with [14C]valine for 5 min before plasma and brain samples were taken for determination of radioactivity and content of individual amino acids. As protein content of the meal was increased from 0 to 50% casein, plasma and brain concentrations of valine and most other large neutral amino acids (LNAA) increased severalfold; also the ratio of [14C]valine in brain to that in plasma decreased by greater than 50%, and the rate of valine entry into the brain increased 3.5-fold. The increase in valine flux slowed as plasma levels of LNAA, competitors for valine transport, increased. The results were far more dependent on protein content of the final meal than on that of the adaptation diet; thus changes in protein intake, as reflected in altered plasma amino acid patterns, markedly altered valine entry into the brain.

The effect of a metabolic inhibitor upon the properties of the cerebral vasculature during a whole-head saline perfusion of the rat

The effect of the metabolic inhibitor 2,4-dinitrophenol (DNP) has been assessed during a simple in situ Ringer solution perfusion of the rat brain. The preparation was perfused, with or without the addition of DNP, for periods ranging up to 30 min. Following this pre-test perfusion, both the vascular permeability and cerebral perfusate flow were assessed. In the absence of DNP significant barrier disruption had taken place by 10 min and the flow rates showed greater fluctuations with time. In the presence of DNP, however, perfusate flow remained constant and the blood-brain barrier remained intact to [14C]mannitol for at least 10 min, but subsequently the flow rate dropped and the barrier began to show evidence of disruption. The unbound visual marker, Evans Blue, was apparently excluded from all regions other than those that are known to lack a blood-brain barrier. The water content of the brain showed no significant increase until 20 min. Patency of the capillaries was demonstrated by direct visualization of the cerebral vasculature with an Indian ink-gelatin mixture and in some animals there was evidence of incomplete filling following 30 min of perfusion. It is concluded that the use of DNP in the perfusate provides a useful preparation for the short-term study of passive properties of the blood-brain barrier, such as carrier-facilitated diffusion, as well as mechanisms of barrier opening.

Transport of thiamin across the blood-brain barrier of the rat in the absence of aerobic metabolism

By employing an anaerobic brain perfusion technique the dependency of thiamin transport across the blood-brain barrier upon high-energy phosphate production has been studied. Analysis of the data revealed essentially identical influx kinetics as those previously reported in vivo, the influx being considerably greater than that for the non-transported small molecule mannitol. These results provide for the first time direct evidence that, unlike at other cell surfaces, the influx of thiamin at the blood-brain barrier is independent of energy-yielding metabolism.

Sex therapy outcome research: a reappraisal of methodology. 1. A treatment study of male sexual dysfunction

In the first section a controlled treatment study of male sexual dysfunction is described. 'Unlucky' randomization of subjects yielded treatment groups which differed with respect to variables of possible prognostic significance. Hence the results are largely uninterpretable. In the second section the predominantly negative or inconsistent findings in sex therapy outcome research are reviewed and methodological problems, such as those described in the first part, are considered as possible reasons for these negative findings. The interrelationships are explored between small treatment groups, prognostic variability, bias, power, and small expected treatment effects. A strategy for future research is proposed, with particular emphasis on the recognition and use of relevant prognostic indices.

The effect of dexamethasone on vascular permeability of experimental brain tumours

The vessels of experimental gliomas show an abnormally high permeability to small polar molecules, such as mannitol. To establish whether this change in vessel permeability is modified by treatment with the corticosteroid dexamethasone, the kinetics of [14C]mannitol transfer into rat astrocytomas were estimated in both steroid-and saline-treated, tumour-bearing animals. This was achieved by injecting [14C]-mannitol i.v., using a specially devised technique, so as to maintain a constant concentration of tracer in the blood plasma. In separate experiments steady levels of the tracer were maintained in the circulation from 1 to 30 min. Mean plasma and tumour radioactivity were measured, and the apparent transfer constant of mannitol across the vascular endothelium and the size of the extravascular extracellular mannitol space in the tumours were calculated. Despite a significant clinical improvement in the treated animals and adequate circulating levels of dexamethasone at the time of the permeability studies, no difference in either the apparent transfer constant for the movement of mannitol into the tumours or the fractional extracellular mannitol space was detected between these animals and the controls. With steroid treatment both tumour-bearing and non-tumour bearing animals lost weight, and in the latter there was no consistent change in routine biochemical or haematological parameters. It was concluded that under these conditions it is unlikely that clinical improvement with dexamethasone therapy was due to a non-specific reduction in tumour vessel permeability to polar substances.

Comparison of the effects of some thiamine analogues upon thiamine transport across the blood-brain barrier of the rat

The flux of thiamine from the blood into the brain has been measured by a specially devised procedure in which a steady raised level of the vitamin, with or without radioactive labelling, was achieved rapidly and maintained steadily in the circulating blood plasma. This was done by a single rapid I.V. injection followed by a continuous injection given at a rate adjusted according to a pre-determined programme, so as to replace the injected material at the rate at which it had been found to leave the circulation in preliminary experiments. A series of four chemical analogues of thiamine were given to see how each affected the flux of thiamine into the brain and the findings are compared with those for a fifth analogue studied in previous work. Pyrithiamine, thiamine disulphide and acetylthiamine, like amprolium, inhibited thiamine transport across the blood-brain barrier. Kinetic analysis shows that they compete mainly for the saturable component of thiamine flux across the blood-brain barrier, with only a slight inhibition of the non-saturable component, most clearly seen with pyrithiamine. Oxythiamine, despite its close chemical similarity to thiamine did not have any significant effect upon the flux of the vitamin into the brain. These findings help to explain the efficacy of pyrithiamine administration, especially in conjunction with a thiamine-deficient diet, in rapidly producing central neurological signs of deficiency.

Maintenance of the integrity of the blood-brain barrier in the rat during an in situ saline-based perfusion

Integrity of the blood-brain barrier to the small polar tracer mannitol was maintained for up to 30 min during an in situ perfusion of the brain with a saline-based solution containing the metabolic inhibitor 2,4-dinitrophenol. The patency of the capillary bed after perfusion was demonstrated by injecting a solution of Indian ink and gelatin, and ultrastructural examination showed the microvasculature to be well preserved. These findings suggest that the blood-brain barrier can be studied under conditions that are independent of normal cerebral function and metabolism.

The dexamethasone suppression test in the puerperium

A consecutive series of 45 women admitted to an obstetric unit were given the dexamethasone suppression test (DST) on days three to five post-partum, 82% being abnormal. The likelihood of an abnormal DST on one or both occasions increased linearly across the days of testing. Subjects completed the Beck self-report depression measure and the General Health Questionnaire at baseline and at six weeks. Baseline cortisol levels were not associated with baseline morbidity as assessed on the questionnaires and were not predictive of morbidity assessed at the six-week follow-up. It is concluded that the immediate post-partum period be included as a false-positive influence on the DST.

The vasculature of experimental brain tumours. Part 4. The quantification of vascular permeability

In order to quantify changes in vessel permeability seen previously in experimental astrocytomas produced in rats by an intracerebral injection of cultured neoplastic glial cells, the flux of mannitol across the vascular endothelium from the blood into the normal brain or tumour tissue was measured using a specially devised technique by which a steady level of radioactively labelled mannitol can be achieved rapidly and maintained in the bloodstream. This is done by a continuous injection given at a rate which is adjusted by a predetermined programme so as to replace the tracer at the rate at which it has been found to leave the circulation in previous experiments. In separate experiments on both tumour-bearing and control rats steady levels of the tracer were maintained in the circulation for progressively longer times of up to 30 min. The kinetic parameters of the process gave estimates for the apparent transfer constant of mannitol across the vascular endothelium and of the size of the extravascular extracellular mannitol space in the tumours. The apparent transfer constant for the movement of mannitol across the blood-brain barrier was increased more than a hundred-fold in the region of the tumour compared to the values for the brain of control rats or that of tumour-bearing rats remote from the tumour site. The extracellular extravascular space within the tumour was estimated to be 22%, somewhat larger than accepted normal values.

Nursing research: a position paper

It is argued herein that orthodox approaches to nursing research reflect a fundamental misunderstanding concerning the nature of nursing, a misunderstanding that results in the production of findings that are perceived as irrelevant to clinical practice. The reasons for this are analysed and two specific research monographs, Hayward (1975) and Ogier (1982) are criticized where appropriate in order to illuminate the analysis. Nursing is explicated as a social phenomenon and practice discipline and the peculiar suitability of action research to its investigation is demonstrated.

Changes in plasma amino acid patterns in chronic alcoholic patients during ethanol withdrawal syndrome: their clinical implications

Changes or imbalances in plasma amino acid patterns during withdrawal from ethanol were recorded in six randomly selected male chronic alcoholic patients (age range 23-47 years). Duration of drinking ranged from 4-15 years and their average daily amount of ethanol intake was more than 100G. Plasma amino acids (taurine, threonine, serine, glutamate, glutamine, proline, glycine, alanine, cysteine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, histidine, tryptophan, ornithine, lysine and arginine) were estimated by autoanalyzer in all patients on admission before starting conventional detoxification therapy for ethanol withdrawal syndrome, and during therapy on day 3 and day 6. On admission, there was a statistically significant rise in the plasma levels of almost all aminoacids, particularly glutamate, glutamine, phenylalanine, proline, glycine, methionine, cysteine, lysine, tyrosine, valine, isoleucine, leucine, serine, threonine, alanine and arginine (in comparison to those of normal controls) in five out of six patients. During the following six days of treatment and total abstinence, the pattern of plasma aminoacid levels did not change significantly despite considerable clinical improvement. Plasma tryptophan levels were undetectable in all patients on admission, day 3 and also on day 6 except in one patient with lesser amount and shorter duration of drinking, the levels just returned to within normal range only on day 6. Plasma levels of histidine and taurine were found to be slightly lower than normal.

Isolation and characterization of high-buoyant-density proteoglycans from bovine femoral-head cartilage

Proteoglycans were extracted from bovine (15-18 months old) femoral-head cartilage. The heterogeneity of the A1D1 proteoglycan fraction was examined by gel chromatography, sedimentation velocity, sucrose rate-zonal centrifugation and CS2SO4 isopycnic centrifugation. In all cases polydisperse but unimodal distributions were obtained. Chemical analysis of the preparation yielded a galactosamine/glucosamine molar ratio of 7:1, and 13C n.m.r. spectroscopy showed that the chondroitin sulphate comprised equal proportions of the 4- and 6-sulphate isomers. Gel chromatography of a papain and Pronase digest of the proteoglycan indicated that the chondroitin sulphate chains had a Mn of approx. 10500. The mean buoyant density of the proteoglycan in pure CS2SO4 was 1.46 g/ml. Physical characterization of the proteoglycan preparation in 4M-guanidine hydrochloride, pH 7.4, by using conventional light-scattering gave a radius of gyration of 42 nm and a Mw of 0.96 X 10(6). Quasi-elastic light-scattering in the same solvent yielded a translational diffusion coefficient, D020, of 5.41 X 10(-8) cm2 X S-1, and ultracentrifugation gave a sedimentation coefficient, S020, of 12.0S. Thus from sedimentation-diffusion studies a Mw of 1.36 X 10(6) was calculated. The possible origins for the differences in the two molecular-weight estimates are discussed. It is concluded that the high-buoyant-density proteoglycans from bovine articular cartilage are significantly smaller than those from bovine nasal septum, and that this is largely due to the smaller size of their chondroitin sulphate chains.

Inhibition of thiamine transport across the blood-brain barrier in the rat by a chemical analogue of the vitamin

The flux of thiamine from the blood into the brain has been measured using a specially devised technique by which a steady raised level of the vitamin, with or without radioactive labelling, can be achieved rapidly and maintained in the bloodstream. This is done by a continuous injection, given at a rate which is adjusted by a pre-determined programme so as to replace the tracer at the rate at which it has been found to leave the circulation in previous experiments. A further programme was worked out to maintain, in a similar manner by a separate injection, a steady raised level in the bloodstream of a chemical analogue of thiamine, 1-[(4-amino-2-propyl-5-pyrimidinyl)methyl]-2-picolinium chloride HCl (amprolium). In the presence of a high concentration of amprolium the flux of thiamine across the blood-brain barrier was greatly reduced and no longer saturable by raising the blood thiamine concentration up to at least 10 microM. It was concluded that this analogue of thiamine inhibited the saturable component of thiamine transport across the barrier but not the non-saturable component. In a further series of experiments, progressively higher levels of thiamine were maintained in the bloodstream and the influx of the vitamin across the blood-brain barrier was measured. From kinetic analysis of the results, it was clear that the affinity of amprolium for the transport carrier was of a similar magnitude to that of thiamine itself. That the inhibition was competitive was shown by the way in which it could be overcome if the level of thiamine in the blood plasma was raised sufficiently above the normal.

Parental representations of schizophrenics and their association with onset and course of schizophrenia

The view that schizophrenics have been exposed to a parental style of low care and overprotection was assessed in a case-control study of 72 schizophrenics using the Parental Bonding Instrument (PBI) which measures perceived parental characteristics. Those who assigned one or both parents to the low care/overprotection group had an earlier age of initial hospitalization, and in nine months following hospital discharge were more likely to be readmitted. The PBI is a simple measure capable of predicting schizophrenic relapse.

Comparison of the cerebral function monitor and plasma concentrations of thiopentone and alphaxalone during total i.v. anaesthesia with repeated bolus doses of thiopentone and althesin

Repeated bolus doses of thiopentone or Althesin were administered to 10 patients every 240 s while cerebral electrical activity was recorded with the Cerebral Function Monitor (CFM). Peripheral venous blood samples were collected at 60 and 225 s after each bolus dose for the measurement of plasma concentrations of the drugs. Significant correlations in the range r = 0.56-0.96 (P = 0.02-0.00001) between plasma thiopentone or alphaxalone concentrations and the upper and lower edges of the CFM trace were found. For the patients with relatively poor correlations, better correlations were obtained when 60- and 225-s sample were analysed separately.

Kinetics of thiamine transport across the blood-brain barrier in the rat

1. By measurement of the rate of disappearance of injected tracer thiamine from the bloodstream, a programme for the continuous injection of thiamine at a variable rate has been devized by which a steady raised level can be achieved rapidly and maintained in the circulation. By this means the flux of radioactive thiamine across the blood-brain barrier has been measured. 2. In separate experiments progressively higher levels of thiamine were maintained in the bloodstream. Evidence was obtained that the transport of thiamine across the blood-brain barrier is a carrier-mediated process which can be saturated by raised levels of thiamine. 3. The saturation of the transport process was incomplete: kinetic analysis showed that there was a non-saturable component of the transport which was probably due to passive diffusion. 4. The contribution of the non-saturable component was normally small and is probably insufficient to meet the needs of the brain for the vitamin unless the concentration of the vitamin in the blood is raised considerably above normal. 5. This two-component transport process had substantially similar kinetic parameters in different regions of the brain.

Treatment of streptozotocin-diabetic dogs with a long-acting somatostatin analog

A long-acting somatostatin analog, Wy-41,747, improved glucose homeostasis in steptozotocin-diabetic dogs. In insulin-withdrawn, fasted dogs, a single 100 μg/kg s.c. injection of Wy-41,747 significantly suppressed plasma glucagon levels for 2 h (a nadir of 53 ± 8% of basal being reached at 1 h) and plasma glucose for 3 h (77 ± 5% of basal); even more potent suppression of glucagon and glucose levels was observed during experiments with 500 μ/kg of Wy-41,747. During meal studies, the combined administration of Wy-41,747 (100 μ/kg) and insulin resulted in lower postprandial glucagon and glucose levels than did the administration of insulin alone. When the somatostatin analog was given alone to fed animals, a rise in glucose occurred 4-5 h after the meal, suggesting the possibility of delayed absorption under these conditions. Improved glucose tolerance profiles followed oral administration of glucose or 14C-3-O-methyl glucose; a normal or near-normal time course of absorption was observed with diminished peak plasma glucose or 14C levels. No major malabsorption of carbohydrate occurred in the 14C-3-O-methyl glucose study, since only low levels of 14C were found in the feces of peptide-treated dogs. No undesirable gastrointestinal effects were noted during these studies. In conclusion, administration of a singlesubcutaneous dose of the long-acting somatostatin analog Wy-41,747 to streptozotocin-diabetic dogs lowered fasting plasma glucose levels and augmented insulin action in lowering postprandial glucose levels.

Oligodendrogliomas of the fourth ventricle: report of two cases

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