Hypertensive and normal pregnancy: a longitudinal study of blood pressure, distensibility of dorsal hand veins and the ratio of the stable metabolites of thromboxane A2 and prostacyclin in plasma

OBJECTIVE

By combining serial measurements of the circulating concentrations of thromboxane A2 and prostacyclin with measurements of venous distensibility (taken during the pregnancies of both normal women and those with pregnancy induced hypertension or pre-eclampsia), to test the following hypotheses: 1. that changes in the venous plasma ratio of thromboxane (TXB2) and 6-keto-PGF1 alpha would correlate with changes in the blood pressure of women developing and recovering from pregnancy induced hypertension or pre-eclampsia and 2. that changes in venous distensibility would correlate with changes in arterial blood pressure in pregnancy induced hypertension or pre-eclampsia.

DESIGN

Prospective, longitudinal cohort study.

SETTING

John Hunter Hospital clinic, Newcastle, Australia.

SUBJECTS

One hundred and sixty primiparous women, recruited when presenting for their first routine antenatal visit, were investigated at, or close to, 19, 28 and 37 weeks of gestation; a subgroup was also studied in the postnatal period. The measurements of the patients who developed pregnancy induced hypertension or pre-eclampsia were compared with those of controls selected from the cohort.

MAIN OUTCOME MEASURES

Serial measurements of the circulating concentrations of the stable metabolites of thromboxane A2 and prostacyclin (TXB2 and 6-keto-PGF1 alpha, respectively), venous distensibility and immediate (no rest) and resting (for at least 30 min) blood pressures.

RESULTS

There was no significant difference between the subject and control groups at any time during or after the pregnancy in the concentrations of prostaglandin metabolites, their ratio or venous distensibility. In contrast, there was a significant difference between the groups at 19 weeks for immediate and resting readings of diastolic pressure (6 mmHg (95% CI 1.5 to 10.5) and 4 mmHg (95% CI 0.1 to 7.9), respectively). These differences increased through the pregnancy but mean postnatal readings for the groups were almost identical suggesting that the subjects were not intrinsically hypertensive compared with controls. Blood pressures for the subject group, both immediate and resting, were significantly different from the 19 week readings at 28 weeks (diastolic) and at 37 weeks (systolic and diastolic). The only significant change from first readings among controls was in postnatal systolic pressure which was significantly higher than 19 week values, probably reflecting the vasodilatation, with accompanying hypotension, of early, normal pregnancy. This difference was not observed in those who subsequently developed pregnancy induced hypertension or pre-eclampsia.

CONCLUSIONS

Our study was unable to demonstrate differences in circulating metabolites or venous distensibility between normotensive women and those with pregnancy induced hypertension or pre-eclampsia. If pregnancy induced hypertension or pre-eclampsia in humans represents not so much the presence of abnormal constrictor influences as a process initiated by failure of normal vasodilatation in early pregnancy, studies carried out later may detect mainly adaptive and secondary changes.

Contrast sensitivity and coherent motion detection measured at photopic luminance levels in dyslexics and controls

Development dyslexics perform differently from controls on a number of low level visual tasks. We carried out three experiments to explore some of these differences. Dyslexics have been found to have reduced luminance contrast sensitivity at mesopic luminance levels. We failed to replicate this finding at photopic luminance levels. We also compared the (photopic) coherent motion detection thresholds of groups of child and adult dyslexics with those of age matched controls. Dyslexics were significantly less sensitive to motion. The results are discussed in relation to a recent suggestion that developmental dyslexia may be associated with a magnocellular visual deficit.

Purchaser-provider: the international dimension

Purchaser-provider systems in health care are being implemented in several countries and are under consideration in many more. These new arrangements are described for the United Kingdom, Finland, New Zealand, and Australia, and in each case responsibility for funding, purchasing, providing, and ownership is identified. The four systems, along with managed care organisations in the United States, are also compared with regard to several important features. There is a fundamental similarity between these purchaser-provider arrangements but several key differences are well worth systematic study. This is a major challenge for academic bodies in Britain and other countries, and the opportunity to learn from each other should not be missed.

Aspects of current and future inhibin research

Inhibin was first isolated in 1985. Major progress has been made in defining various aspects of its structure and physiology, using a heterologous radioimmunoassay. Current research is aimed at characterizing the nature of the circulating forms of inhibin and is examining whether there are sex-specific roles for inhibins A and B. It has been recognized that various forms of epithelial and stromal ovarian cancer produce members of the inhibin peptide family but the precise nature of these products is not yet clear. The recognition that the inhibin subunits together with follistatin are expressed locally within the pituitary has lead to an investigation of their possible roles in intrapituitary regulation. It is clear that these peptides also have intragonadal roles. Of particular current interest is the nature of the signals that control the specificity of cellular peptide production and that determine whether a particular cell produces inhibin or activin. The inhibins are members of a complex family with many potential roles in physiology and pathophysiology. The role of the inhibins in feedback control of follicle stimulating hormone in the male, particularly, remains unclear. New applications for inhibin and related peptides are likely to be developed.

Immunohistochemical analysis of cathepsin D in prostate carcinoma

Cathepsin D is a carboxyl protease that has been implicated as an important factor in tumor cell invasion. Sixty-nine cases of primary adenocarcinoma of the prostate were studied by the indirect immunoperoxidase method using a primary monoclonal anti-cathepsin D antibody. Immunoreactivity was graded from 0 (negative) to 4+ (intense reaction). The normal tubuloalveolar glands were, in general, negative. However, nine cases revealed focal staining of nonneoplastic luminal cells. Basal cells were negative except in areas of basal-cell hyperplasia, which were intensely positive. Thirty-nine of 78 carcinoma samples revealed 2+ or greater positive punctate lysosomal staining. In the 39 positive-stained cases, the reactivity was diffuse in three and focal in the remainder. The percentage of carcinoma cases whose worst lesions stained 2+ or greater showed a nonsignificant (P = 0.055) relation to Gleason grade but a significant (P = 0.031) relationship to pathologic stage. Thus, cathepsin D may prove to be a useful marker of prostate cancer progression.

Colonic preparation with Picolax: patient tolerance and approaches to fluid replacement

Sodium picosulphate (Picolax) is widely used for bowel preparation prior to colonic investigation or surgery. The most troublesome side effect reported is headache, which has been thought to be due to dehydration. In a prospective randomized study we investigated the incidence of adverse effects in patients given Picolax prior to barium enema examination, and assessed the incidence of adverse effects with different oral fluid regimens. A total of 197 outpatients were allocated to one of five fluid regimens on the day prior to the enema: (a) 4 pints of Dioralyte (glucose and electrolyte solution); (b) 4 pints of half-strength Dioralyte; (c) 4 pints of water; (d) 6 pints of water; and (e) free fluids. In a questionnaire, 36% of patients had no headache (graded 0/5), while 38% had a significant headache (graded 3/5 or greater). Sixteen per cent had significant abdominal pain, 42% had dry mouths, 43% thirst and 34% tiredness or irritability. There was no correlation between headache and fluid regimen. Furthermore, we have found no evidence of dehydration. None of the five fluid regimens was shown to offer any advantage, and we therefore recommend that patients be allowed to drink according to thirst when taking Picolax.

Integrated specialty and operational system for diabetes management in south west England

The management and control of diabetes throughout South West England has been assisted by the use of a networked computerised information system which is totally integrated with hospital and community information systems. The objectives of the diabetes system are to produce an aid to diabetes management, which includes the creation of a district diabetes register accessed and maintained by clinicians based in both the hospital and in the community, whilst at the same time providing auditable information.

Hepatitis B virus replication in diverse cell types during chronic hepatitis B virus infection

Hepatitis B virus-specific nucleic acid sequences and proteins have been detected in extrahepatic tissues of acutely and chronically infected patients. However, apart from peripheral blood mononuclear cells and bone marrow cells, little is known about the specific cell types that permit viral replication. In this study, we assessed the extrahepatic tissues of four patients who died with chronic hepatitis B virus infection and two uninfected controls by means of in situ hybridization and immunohistochemical study. Three of these patients had diffuse extrahepatic distribution of the virus. Hepatitis B virus nucleic acid sequences and proteins were detected in the lymph nodes, spleen, bone marrow, kidney, skin, colon, stomach, testes and periadrenal ganglia. The following cell types were found to be positive for hepatitis B virus: endothelial cells, macrophages/monocytes, hematopoietic precursors, basal keratinocytes, mucosal epithelial cells, stromal fibroblasts and sustentacular and neuronal cells. It is probable that these cells could support viral replication because hepatitis B virus DNA replicative intermediates, viral transcripts and HBsAg and HBcAg proteins were detected in most. These findings may be relevant to the initiation of extrahepatic syndromes associated with chronic hepatitis B virus infection such as vasculitis, glomerulonephropathy, neuropathy and dermatitis.

Electrophysiology and burst-firing of rat subicular pyramidal neurons in vitro: a comparison with area CA1

Intracellular recordings were made from subicular and CA1 neurons in slices of the ventral hippocampal and parahippocampal region of the rat. All of the subicular cells that were stained by intracellular injection of biocytin were pyramidal in form. Although most electrophysiological properties were similar in the two areas, in response to depolarising current injection, the majority of subicular cells displayed a distinctive pattern of burst-firing which was rarely seen in CA1 cells. Burst-firing was voltage sensitive but was not abolished by blocking excitatory synaptic transmission, suggesting that it is an intrinsic membrane property of subicular pyramidal cells.

Serum and liver hepatitis B virus DNA in chronic hepatitis B after sustained loss of surface antigen

Polymerase chain reaction (PCR) was used to detect hepatitis B virus DNA in the sera and livers of nine patients with chronic hepatitis B after treatment-induced or spontaneous loss of serum hepatitis B surface antigen. Patients were evaluated at intervals ranging from 3 to 67 months after disappearance of hepatitis B surface antigen. PCR was performed using primer pairs from the surface and core gene regions, and surface gene products were quantitated. Liver tissue was also evaluated by in situ hybridization to assess viral transcription. Five of the nine patients had viral DNA detectable in serum by PCR. Quantitation of polymerase chain reaction products in serum and liver showed that the DNA levels tended to decline progressively after antiviral therapy. Six of seven surface antigen-negative patients tested had detectable viral DNA in the liver, and four of the six DNA-positive patients were negative for DNA in serum by PCR. None had surface gene messenger RNA. Thus, it is concluded that hepatitis B virus DNA may be detectable by PCR in liver tissue years after the disappearance of hepatitis B surface antigen, even in the absence of detectable hepatitis B virus DNA in serum.

A comparison of four methods for projecting households

"The purpose of this paper is to extend the headship rate method for projecting households to encompass both sexes. Four models are considered that explicitly incorporate the impact of changes in the number of men and women on the number and joint age distribution of husband-wife households. The models are applied to the Philippines using data from the 1988 National Demographic Survey to project households to 2010. The models are also evaluated by 'backcasting' and comparing the results with special tabulations from the 1970 and 1980 censuses and the 1975 National Demographic Survey."

Hepatitis B virus DNA in peripheral-blood mononuclear cells in chronic hepatitis B after HBsAg clearance

In this study, peripheral-blood mononuclear cells from patients with chronic hepatitis B and spontaneous or therapy-induced disappearance of HBsAg were examined for HBV DNA. Samples were evaluated by in situ hybridization and polymerase chain reaction both before and after clearance of HBsAg. By in situ hybridization, positive signals were observed in 2 of 13 samples collected after HBsAg loss, in 8 of 15 samples before HBsAg loss and in 0 of 4 control patients without serological markers of active or prior HBV infection. When polymerase chain reaction analyses were performed, HBV DNA was detected in 5 of 12 HBsAg-negative samples and 10 of 15 HBsAg-positive samples from the study group. Testing of mononuclear cells after disappearance of HBsAg revealed that two of eight patients were HBV DNA positive by in situ hybridization and by polymerase chain reaction, whereas two additional patients were positive by polymerase chain reaction alone. Mononuclear cell-associated HBV DNA was detected between 2 and 9 mo after the disappearance of circulating HBsAg by in situ hybridization and as long as 4 yr later by polymerase chain reaction. These data indicate that patients who have undergone HBsAg seroconversion may nonetheless harbor HBV DNA in their peripheral-blood mononuclear cells for prolonged periods.

Adjuvant psychological therapy for patients with cancer: a prospective randomised trial

OBJECTIVE

To determine the effect of adjuvant psychological therapy on the quality of life of patients with cancer.

DESIGN

Prospective randomised controlled trial comparing the quality of life of patients receiving psychological therapy with that of patients receiving no therapy, measured before therapy, at eight weeks, and at four months of follow up.

SETTING

CRC Psychological Medicine Group of Royal Marsden Hospital.

PATIENTS

174 patients aged 18-74 attending hospital with a confirmed diagnosis of malignant disease, a life expectancy of at least 12 months, or scores on various measures of psychological morbidity above previously defined cut off points.

INTERVENTION

Adjuvant psychological therapy, a brief, problem focused, cognitive-behavioural treatment programme specifically designed for the needs of individual cancer patients.

MAIN OUTCOME MEASURES

Hospital anxiety and depression scale, mental adjustment to cancer scale, Rotterdam symptom checklist, psychosocial adjustment to illness scale.

RESULTS

156 (90%) patients completed the eight week trial; follow up data at four months were obtained for 137 patients (79%). At eight weeks, patients receiving therapy had significantly higher scores than control patients on fighting spirit and significantly lower scores on helplessness, anxious preoccupation, and fatalism; anxiety; psychological symptoms; and on orientation towards health care. These differences indicated improvement in each case. At four months, patients receiving therapy had significantly lower scores than controls on anxiety; psychological symptoms; and psychological distress. Clinically, the proportion of severely anxious patients dropped from 46% at baseline to 20% at eight weeks and 20% at four months in the therapy group and from 48% to 41% and to 43% respectively among controls. The proportion of patients with depression was 40% at baseline, 13% at eight weeks, and 18% at four months in the therapy group and 30%, 29%, and 23% respectively in controls.

CONCLUSIONS

Adjuvant psychological therapy produces significant improvement in various measures of psychological distress among cancer patients. The effect of therapy observed at eight weeks persists in some but not all measures at four month follow up.

Effects in vivo of purified recombinant human activin and erythropoietin in mice

Activin has been shown to act in vitro as an erythroid specific enhancing activity for erythropoietin (epo)-stimulated erythroid (BFU-E) and multipotential (CFU-GEMM) progenitor cells. To evaluate effects in vivo, purified recombinant activin-A and epo were administered s.c. to hypertransfused polycythemic mice for analysis of iron (59Fe) uptake, and to previously untreated mice for effects on reticulocyte release and proliferation of bone marrow (BM) and spleen (Spl) hematopoietic progenitors (CFU-GEMM, BFU-E, CFU-GM) and BM stem (CFU-S) cells. Activin alone had no effect in polycythemic BDF1 mice, but synergised with epo to significantly enhance 59Fe-incorporation into erythrocytes. In untreated C3H/HeJ mice, a single dose of activin enhanced reticulocyte release in 24 h to the level seen with epo. Activin plus epo did not further enhance reticulocyte release. Reticulocyte release was still apparent at day 4 in mice given epo twice a day for 3 days, but not in mice given activin twice a day for 3 days. Activin or epo each significantly enhanced the percent cells in S-phase of BM and Spl CFU-GEMM, BFU-E and CFU-GM in C3H/HeJ, W/Wv and Sl/Sld mice and BM CFU-S in BDF1 mice. The combination of epo plus activin did not further enhance proliferation. These results demonstrate activin's erythropoietic enhancing activities in vivo, and also activin and epo induction of enhanced proliferation of non-erythroid, as well as erythroid progenitors.

Primary structure and biological activity of human brain-derived neurotrophic factor

Brain-derived neurotrophic factor (BDNF) is a 27-kDa basic protein of noncovalently linked 13.5-kD subunits related to nerve growth factor and is produced by the central nervous system (CNS). BDNF has been shown to promote the survival of neurons located in or directly connected with the CNS and is likely to function in adjusting the cell number within neuronal populations to the need of this projection field. Here we describe the primary structure of a human BDNF cDNA, the biological activities of pure recombinant human BDNF, and the tissue distribution of rat BDNF. BDNF mRNA can be found in some peripheral tissues as well as in the CNS, and recombinant human BDNF is a potent neurotrophic factor for primary peripheral sensory neurons.

Ossifying parotid carcinoma ex pleomorphic adenoma: CT findings

The CT appearance of a large necrotic carcinoma ex pleomorphic adenoma of the parotid gland is described. The tumour contained trabecular bone, which was correctly identified on a preoperative CT examination and which indicated the origin of the tumour to be a benign pleomorphic adenoma. This degree of macroscopic bone formation is rare in pleomorphic adenoma, and its demonstration by CT has not been previously reported.

Effect of recombinant inhibin on gonadotropin secretion during proestrus and estrus in the rat

This work investigated the ability of recombinant human (rh) inhibin A or the GnRH antagonist [Ac-D2Nal1, delta Cpa2, delta 3Pal3, Arg5 delta 5-(p-methoxyphenyl)5-oxo-2-aminopentanoic acid6, delta Ala10]GnRH to alter plasma immunoreactive LH and FSH levels in cycling female rats. In a first series of experiments, rh inhibin A (25 micrograms/kg) was injected iv between 0800 and 0830 h, or at 0800 and 1200 h, on proestrus, and plasma hormone levels were measured from 1200-1900 h. Both regimens of administration significantly (P less than or equal to 0.01) lowered mean plasma FSH levels but did not mask the primary FSH surge. This treatment also lowered the overall amount of LH released, although the difference between control and inhibin-treated rats only reached statistical significance (P less than or equal to 0.05) after two injections of the protein. Measurement of the number of tubal ova shed on the next estrus showed no difference between rats injected with the vehicle or inhibin at 0830 h. Finally, it was shown that administration of the GnRH antagonist (100 micrograms/kg) at 1200 h interfered with the primary surges of both LH and FSH. In a second series of experiments, rh inhibin A (25 micrograms/kg) was injected once at 2000 h on proestrus. In these animals, inhibin significantly (P less than or equal to 0.01) decreased mean plasma FSH levels between 2000 h on proestrus and 0500 h on estrus and totally suppressed the secondary FSH surge. LH secretion remained low in control animals, and no measurable changes were observed after inhibin treatment. Flushing of the ova 5 days later (i.e. during estrus of the subsequent cycle) showed no difference between control and inhibin-treated rats. Injection of the GnRH antagonist (100 micrograms/kg) at 2000 h on proestrus decreased the total amount of FSH secreted during late proestrus and early estrus. However, FSH secretion showed an increase at between 0100 and 0400 h of estrus despite blockade of GnRH receptors. These results indicate that administration of rh inhibin A interferes with both the primary and secondary FSH surges. In contrast to its inability to alter LH release by ovariectomized rats, inhibin also blunted LH secretion during the afternoon of proestrus. Whether these results represent differential effects of inhibin on LH secreted by intact and gonadectomized animals, or whether the documented changes in pituitary responsiveness to GnRH during proestrus are accompanied by an increased sensitivity to inhibin, needs further investigation.

Effect of recombinant inhibin on luteinizing hormone and follicle-stimulating hormone secretion in the rat

We investigated the effect of the iv injection of recombinant human (rh) inhibin on FSH and LH secretion in the female rat under various experimental circumstances. Rh inhibin caused dose-related decreases in mean plasma FSH, but not LH, levels in ovariectomized female rats 14 days old and older. The duration of this inhibition was proportional to the dose of rh inhibin, but no consistent changes in FSH secretion were observed until 4 h after treatment. Maximum suppression of FSH release was observed at about 15 micrograms rh inhibin/kg BW and lasted 8-10 h. Measurement of the area under the curve from 4-12 h after injection of inhibin indicated a dose-related decrease in total FSH secreted. When blood samples were withdrawn every 10 min to evaluate pulsatile gonadotropin release, analysis of FSH pulse parameters indicated that rh inhibin (25 micrograms/kg) interfered with pulse frequency, amplitude, and peak levels in both intact and ovariectomized rats. In contrast, pulsatile LH secretion was not measurably altered. These results demonstrate that rh inhibin acts primarily at the level of the pituitary to inhibit all parameters of FSH secretion and suggest that this effect is at least not entirely mediated by changes in GnRH receptors.

Synaptic transmission between individual pyramidal neurons of the rat visual cortex in vitro

Synaptic transmission between pairs of neurons in layer 2/3 of in vitro slices from the rat visual cortex was studied by dual intracellular recording. The intrinsic electrophysiological properties of these neurons suggested that they were pyramidal cells. More than 1/3 of the total number of synaptically connected neurons were stained by intracellular iontophoresis of biocytin, and all had pyramidal morphology. Postsynaptic potentials (PSPs) were evoked by single action potentials (elicited by current injection) in presynaptic cells. Measurements of PSP latency, amplitude, and shape were made on spike-triggered averages. Forty-eight synaptic connections were found out of a possible total of 549, equivalent to a probability of about 0.09. For these 48 connections, the distance between the 2 impalement sites ranged from 50 to 340 microns. All PSPs were depolarizing at rest (-74 +/- 5 mV, mean +/- SD), and all 14 of the PSPs that were also recorded with the postsynaptic cell depolarized to around action potential threshold (about -55 mV) remained depolarizing. PSPs had short latencies (1.2 +/- 0.6 msec, mean +/- SD), suggesting that they were mediated by monosynaptic pathways. Peak amplitudes of the averaged PSPs varied widely (range, 0.05-2.08 mV), but the majority were less than 0.5 mV. PSPs decayed exponentially with time constants that were correlated with, but slightly longer than, the membrane time constants of the postsynaptic cells measured using injected current pulses. Four cell pairs were connected reciprocally, and 6 examples of convergent input were found in which a single cell was postsynaptic to more than 1 presynaptic cell. Trial-to-trial fluctuations in PSP amplitude were analyzed for 16 synaptic connections. The amplitude of the PSP evoked by a presynaptic action potential fluctuated more than could be accounted for by the background noise.

Using census data for household projections: an overview of results from the HOMES Project

"This article provides an overview of the household projection model HOMES [a computer model developed to forecast the number and characteristics of households] and presents new household projections for six countries--China, Indonesia, Japan, the Republic of Korea, Thailand, and the Philippines. The household projections are based on recently released population projections from The World Bank and on rules governing living arrangements quantified with the latest available census or demographic survey for each country. Growth in the number of households to the year 2030 is projected along with changes in household membership and the dependency burden."

Role of CD2 in regulation of CD3- LGL function

CD2 is a differentiation marker present on T cells and NK cells. Cytotoxic T lymphocytes (CTL) can be activated by antibodies directed against the CD3/T-cell receptor complex and CD2 structures; however, the role of CD2 in regulation of CD3- large granular lymphocyte (LGL) functions has only recently been studied. Anti-CD2 monoclonal antibodies (mAbs) may be either augmenting or inhibitory and T-cell activation via the CD2 molecule occurs only when mAb binds defined combinations of the CD2 epitopes. Since LGL can be activated by a single stimulus (e.g., IL-2) to proliferate, produce IFN gamma, and increase their cytolytic potential, these functions were chosen to examine the effects of the anti-CD2 mAb and its combinations. Anti-CD2 mAb (D66, GT2, and X11-1) were incubated with LGL for various times in the absence or presence of IL2 and IFN gamma production was monitored. Single anti-CD2 mAb treatment demonstrated minimal augmentation of IFN gamma production. However, combinations of anti-CD2 (9.6) and the other anti-CD2 mAb resulted in a significant, synergistic enhancement of the IFN gamma production. Anti-CD2 mAb treatment appeared to inhibit production generated by optimal doses of IL-2 (1,000 U/ml). The effect of anti-CD2 mAb on IFN gamma production parallel their effects on LGL NK and LAK activity. These data suggested that mAb against the CD2 molecule were important in regulating LGL functions in the absence of a functional CD3 receptor in LGL.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlations between morphology and electrophysiology of pyramidal neurons in slices of rat visual cortex. I. Establishment of cell classes

The purpose of this study was to determine whether different classes of neocortical pyramidal neurons possess distinctive electrophysiological properties. Neurons were assigned to classes on the basis of their somadendritic morphology as revealed by intracellular HRP injection. The electrophysiological features of each class are compared in the following paper (Mason and Larkman, 1990). Coronal slices were prepared from the visual cortex of the albino rat and maintained in vitro. Pyramidal neurons from layers 2/3 and 5 were impaled with electrodes containing HRP. After intracellular recording, the cells were injected, reacted to visualize the enzyme, and examined in the light microscope. The 18 neurons from layer 2/3 showed an underlying similarity of somadendritic morphology and were considered to constitute a single cell class, although some features varied with the depth of the soma in the cortex. The 22 layer 5 cells were more diverse and were divided into 2 main classes. Eleven cells had single, thick apical trunks which ascended to close to the layer 1 border then branched to form a terminal arbor. These cells were termed thick layer 5 cells, and were found mainly in the upper part of the layer. Ten layer 5 cells had single apical trunks which tapered to a fine diameter and terminated, without forming an obvious terminal arbor, near the top of layer 4 (3 cells) or in layer 2/3 (7 cells). These cells were termed slender layer 5 cells and were found throughout the layer.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlations between morphology and electrophysiology of pyramidal neurons in slices of rat visual cortex. II. Electrophysiology

The aim of this study was to determine whether the different morphological classes of pyramidal neurons in layers 2/3 and 5 of rat visual cortex (Larkman and Mason, 1990) have particular electrophysiological properties. Neurons in in vitro slices of rat visual cortex were impaled with glass micropipettes containing horseradish peroxidase (HRP) and studied using current-clamp techniques prior to pressure injection of HRP into the neurons. On morphological grounds, cells stained in layer 2/3 were placed into a single class whereas layer 5 cells were divided into 2 classes. Cells in one of these classes had thick apical dendrites which arborized in layer 1, whereas the apical dendrites of cells in the other class were thinner and did not reach layer 1 (Larkman and Mason, 1990). Despite variation between individual cells of a single class, significant differences were found in the time constants, current/voltage relations, and repetitive firing behaviors of the 3 classes. Burst firing responses to injected current pulses were confined to the layer 5 cells with thick apical dendrites. These results add to those from other areas of the brain demonstrating that the electrophysiological properties of pyramidal neurons are heterogeneous. Furthermore, we have shown that distinctive intrinsic membrane properties of pyramidal neurons in visual cortex are correlated with different morphologies.

Just for the record

An efficient health service cannot function without an efficient records system. In the first of three articles, Dina Tetlow and Alastair Mason examine some of the issues involved.

Superovulation and embryo recovery in goats treated with ovagen and folltropin

The purpose of the present study was to examine ovulation rates and embryo numbers and quality in goats of feral origin following treatment with either Folltropin (Vetrepharm Inc., Ontario, Canada) or Ovagen (Immuno-Chemical Products Ltd., Auckland). The mean +/- s.e.m. numbers of corpora lutea (CL) and embryos recovered after Ovagen treatment (N = 17 animals) were 16.2 +/- 2.1 and 12.6 +/- 1.9 respectively whereas after Folltropin treatment (N = 18 animals), the respective numbers were 16.3 +/- 1.8 and 10.2 +/- 1.6. The mean +/- s.e.m. numbers of good (i.e. transferable) embryos were 11.1 +/- 1.8 in the Ovagen group and 7.9 +/- 1.4 in the Folltropin group. AII the above values for each of the treatment groups were not significantly different from one another. There was a significant linear relationship between the number of CL and number of embryos (p<0.01; R = 0.925) after Ovagen treatment whereas there was no significant relationship after FolItropin treatment (p>0.05; R = 0.461). The proportions of animals producing more than five recoverable embryos after Ovagen (i.e. 76%) or Folltropin treatment (i.e. 72%) were similar although 22% of the Folltropin treated animals produced abnormal or prematurely regressing CL whereas no such CL were found after Ovagen treatment.

The in vitro slice preparation for combined morphological and electrophysiological studies of rat visual cortex

The morphological condition of slices of rat visual cortex, maintained in vitro in an interface-type recording chamber, was assessed. In addition, neurones in these slices were impaled with glass micropipettes for intracellular recording and horseradish peroxidase (HRP) injection. After fixation and embedding, slices were examined by light and electron microscopy. Slices sectioned orthogonally to the original plane of cutting showed a vertical zonation of tissue preservation. The upper zone contained dense and flattened neuronal somata, although the neuropil appeared normal. The central zone was well preserved, with the appearance of most somata, dendrites, axons and synapses comparing favourably with perfusion-fixed material. The lower zone contained many abnormal, vacuolated somata. The morphology of HRP-injected neurones was assessed by light microscopy. Dendrites could be visualised in great detail and spines were clearly visible. Local axon arbors were well represented. There was good correlation between electrophysiological and morphological criteria for the assessment of the condition of the slice. We conclude that, provided the extent of degeneration within the slice is monitored and appreciated, slices of visual cortex can provide both electrophysiological and morphological data of high quality.

Electrocardiographic monitoring of cardiac transplants in mice

In the murine cardiac model for vascularised transplantation graft function may be monitored by direct palpation, electrocardiography, and graft histology. To assess the merits of these methods, and to measure ischaemic damage, isografts and allografts were examined at regular intervals from 0 to 60 days after grafting. Heart transplants were vascularised from the abdominal great vessels, using microsurgical techniques, with ischaemic times of less than 60 min. Isografts showed no decrease in heart rate over 60 days, as measured by palpation and electrocardiography, but the voltage of the ventricular complex fell progressively over the first 28 days after grafting then remained stable for more than 60 days. The voltage drop was associated with atrophy of myocardial tissue. Allografts in recipients treated with rabbit antimouse antilymphocyte serum were maintained for more than 60 days with little change in palpation rate or recorded heart rate but with significant falls in ventricular complex voltage, reflecting myocardial atrophy and fibrosis. Untreated allografts were rejected in 10-14 days and showed a rapid fall in palpated heart rate, measured heart rate, and ventricular complex voltage. Thus, in this study, palpation of the heart graft gave an accurate measure of the pulse rate and correlated with electrical activity in acutely rejecting grafts, but in long surviving grafts measurement of ventricular complex voltage showed myocardial damage that was not detectable by direct palpation.

The replacement effect and comparisons of per capita income across countries: a short note

This article is intended to clarify two aspects of Leibenstein's replacement effect that have not been adequately addressed in print. First, formal analysis of the replacement effect demonstrates that it is not determined by the quality of entering and departing workers alone but, rather, by the entire age schedule of labor quality. Second, a simple model is used to demonstrate the absence of welfare implications associated with the replacement effect and to quantify the magnitude of the replacement effect.

A method for intracellular injection of horseradish peroxidase by pressure

A technique for intracellular injection of horseradish peroxidase and other tracers into neurones is described. The method utilises gas pressure to force the tracer solution out of glass micropipettes and allows electrophysiological recordings to be made simultaneously with the injection process. Constructional details of the simple and inexpensive equipment are given. The method has the advantages of being equally suitable for charged and uncharged tracer molecules, and of providing reliable indication of the success of the injection at the time of the injection attempt.

Tinkering with successful synapse regeneration in the leech: adding insult to injury

In the leech, synapse regeneration in adults and synapse formation during embryonic development can be studied in single, identifiable cells that make precise connections with their targets. Certain cellular components, such as synaptic targets and glia, were selectively destroyed to study how the regenerating axons locate their targets, what triggers axons to start growing and what stops them. The results showed that glia and targets play only a limited role in synapse regeneration and in axon degeneration. For example, contact with the synaptic target may inhibit sprouting and availability of targets may promote it. Comparative studies on axon growth and synapse formation by interneurones in embryos showed that regeneration does not simply recapitulate embryonic development. There are clearly separate constraints on the two processes. Axon survival is a different problem. Although isolated axon segments can survive for up to a year in the leech, temperature is a major factor in survival. Axon segments in a tropical leech that regenerates synapses well at 31 degrees C degenerated within 2–3 weeks at this elevated temperature, even when regeneration was prevented. In similar leeches at room temperature (22 degrees C), segments survived for months. Overall, results in the leech support the idea that degeneration as well as regeneration share fundamental mechanisms with other invertebrates and the vertebrates, including mammals. Perhaps long-lived axon segments and other features of the leech that speed or encourage functional regeneration can now be made to operate in repair of the mammalian nervous system.

Making medical records professional(s)

In 1986 a joint medical records project group was set up by the Institute of Health Services Management, the Association of Health Care Information and Medical Records Officers and the NHS Training Authority, with Mr Vic Peel as chairman. The group was supported by Arthur Andersen & Co, management consultants. The following is a shortened and edited version of an interim report drafted for the group by Dr Alastair Mason. It is intended for discussion and does not yet represent the definitive views of the sponsoring bodies.

Occult (non-surface expression) of T, B and monocyte markers in human large granular lymphocytes

Human large granular lymphocytes were examined for non-surface expression with a panel of monoclonal antibodies to T cell, B-cell and monocyte markers. T101, antibody to the T65 antigen, showed binding to crude fractions containing intracellular membranes but not to immobilized whole cells. Non-surface expression of T65 was also demonstrated by flow cytometry using lysolecithin to transiently permeabilize cells. With the latter technique nonsurface expression was also demonstrated with monoclonal antibodies B2 and MO-2. T65 was shown to be synthesized by large granular lymphocytes by metabolic labeling, indirect immunoprecipitation and SDS-PAGE. T65 from large granular lymphocytes was the same mol. wt as antigen for T cells derived from the same donor. These results indicate that human large granular lymphocytes synthesize, but do not express on the surface, certain monoclonal antibody-derived markers heretofore considered specific for other cell lineages.