Attendance patterns in general practice

OBJECTIVE

To determine the completeness of data acquired previously on the attendance patterns of patients visiting three general practices and the exclusivity of attendance at these practices.

DESIGN

A retrospective comparison of attendance data with data extracted from the Health Insurance Commission database. Three study practices were investigated to give a rough cross-section of general practice in Western Australia.

RESULTS

Eighty-nine per cent of patients and 92% of services recorded in our earlier study were also recorded by the HIC, with 31% of patients also attending another general practice during the six months, mostly only once or twice. However, there was considerable variation between practices in data match and attendance at other practices.

CONCLUSIONS

We found a high level of completeness of data. Sixty-nine per cent of patients attended no other practice during the six months, indicating that doctors in the study practices have some opportunity to provide continuity of care to their patients. The implications for patients' needs and doctors' resources of variations in attendance patterns need to be examined further.

Reducing donor exposure in preterm infants requiring multiple blood transfusions

Preterm infants frequently require multiple blood transfusions. Traditionally, 'fresh' (less than seven days old) blood has been used but this often results in transfusions from multiple donors. To reduce donor exposure the policy for top-up transfusions was changed. A unit of blood under five days old with additional satellite packs was ordered for each infant and used up to its expiry date, allowing up to eight transfusions from a single donation to be given. The mean (SD) number of transfusions per infant in 43 infants transfused according to previous policy and in 29 transfused according to the new policy was similar at 5.6 (4.0) and 5.3 (3.1), respectively. However, donor exposure fell following the change in policy from 4.9 (3.5) to only 2.0 (0.9). Only one infant was exposed to more than three donors compared with 24 infants in the control group. Plasma potassium concentrations were not significantly different following transfusion of blood stored for up to 33 days. This simple change in policy has reduced donor exposure in infants requiring multiple top-up transfusions.

Stability of attendance in general practice

Data on the attendances of all patients at three general practices in Western Australia for two 6-month periods 11 months apart were collected as part of a previous study. The present study examined the stability of the attendance patterns of the patients over the two study periods in terms of number of patients, number of visits and diagnoses. The patients who attended in both study periods were classified into four attendance groups: low to low; low to high; high to low; and high to high. The age, sex and diagnoses for each were compared. The results showed that whilst the patient populations remained constant over the two periods, these populations were not comprised of the same patients. Only 45% of those who attended in the first 6 months also attended in the second. Similarly, whilst 8% of patients in each study period were classified as high attenders, only 22% of the high attenders in the first period were also high attenders in the second. The long-term high attenders were older and suffered from chronic diagnoses. The short-term high attenders were found to suffer from more self-limiting diseases and conditions such as depression and pregnancy.

Effect of zinc, copper and glucocorticoids on metallothionein levels of cultured neurons and astrocytes from rat brain

The knowledge of brain metallothionein (MT) regulation and especially of MT presence in specific cell types is scarce. Therefore, the effect of several well-known MT inducers, measured by radioimmunoassays using antibodies that cross-react with MT-I and MT-II or specific for MT-I and which do not cross-react with human growth inhibitory factor (GIF or MT-III), has been studied in primary cultures of neurons or astrocytes obtained from rat cerebrum. MT-I levels in glial cells were about ten times higher than those in neuronal cells (538 +/- 194 vs. 49 +/- 16 pg MT-I/micrograms protein, mean +/- S.D. from three separate cell preparations). Increasing the concentration of Zn in the bovine serum albumin (BSA)-containing culture medium up to 50 microM significantly increased MT-I levels by up to 3.5-fold in neurons and 2.5-fold in astrocytes. In contrast, Cu up to 50 microM increased MT-I levels in a saturable manner in both neurons (up to 5-fold) and astrocytes (up to 1.5-fold), the maximum effect occurring at 5 microM Cu. In general, the combination of Zn and Cu further increased MT-I levels. The effect of the metals on MT-I appeared to reflect metal uptake, since MT-I induction was less marked when the BSA concentration in the medium was increased from 2 to 10 mg/ml. Dexamethasone increased MT-I levels in both neurons and astrocytes in vitro in a concentration-dependent manner. Endotoxin, IL-1 and IL-6 did not have a significant effect on glial MT levels at the concentrations studied. The administration of dexamethasone to rats increased MT-I levels in non-frontal cortex, cerebellum, pons+medulla, midbrain and hippocampus, but not in hypothalamus, frontal cortex and striatum. Endotoxin increased liver but not brain MT-I levels. Immunocytochemical studies in adult rat brain preparations with a polyclonal antibody that cross-reacts with MT-I and MT-II indicated that immunostaining was always nuclear in glial cells, whereas in neurons it was nuclear in the cerebral cortex, hippocampus and the granular layer of the cerebellum, and nuclear plus cytoplasmic in Purkinje cells in the cerebellum, hypothalamic nuclei and gigantocellular reticular nucleus in the brain stem. Meninges, choroidal plexus, ependymal and endothelial cells were also MT-immunoreactive.

Efficacy of urgent thoracotomy for trauma in patients attended by a helicopter emergency medical service

Over a 12-month period the Helicopter Emergency Medical Service underwent 1084 missions attending casualties in the London area. Sixteen patients required an emergency thoracotomy for resuscitation, nine of which were performed at the scene and seven in the emergency department. The median injury severity score of these patients was 29.9 (SIR 11.8) of which 11 had suffered blunt injuries. Medical attention at scene was administered 16.2 min (SIR 4.0) following the London ambulance service receiving the emergency call. Significantly longer time was spent attending patients who had a scene thoracotomy (35.1 min SIR 16.4) compared with those in whom the thoracotomy was performed in the casualty department. No patient in this series survived resuscitative thoracotomy. It is suggested that scene thoracotomy be abandoned and emphasis placed upon the rapid transport of patients to an emergency facility. This enables other resuscitative measures in addition to thoracotomy to be applied effectively and concentrated over a brief period by a multidisciplinary team.

Patterns of cell behaviour underlying somitogenesis and notochord formation in intact vertebrate embryos

We have made a detailed analysis of cell behaviour using high resolution time-lapse microscopy of the earliest cellular interactions taking place during morphogenesis of the notochord and somites in intact teleost embryos. Notochord formation is typified by active intercalation of paraxial mesenchyme cells into the lateral surfaces of the primordium. Following this recruitment phase, complete immiscibility develops between cells of the notochord and the presomitic mesenchyme. Dorso-ventral and rostro-caudal expansion of the notochord is characterised by translocation of cells within dorso-ventral planes of section and is supported by elongation of the remaining cells and reduction in width across its latero-medial axis. A lateral palisading of paraxial mesenchyme against the lateral aspects of the notochord precedes overt segmentation. Intersomitic furrows form by localised de-adhesion at small foci at the nascent intersomitic planes, which are consolidated by coalescence of such areas by de-adhesion to produce the interface. It is not possible to predict precisely where cells would initiate de-adhesion since there is a stochastic element to the phenomenon. Once formed, boundaries between somites are stable and provide no opportunity for mixing, except across the first formed furrow, which disintegrates at the 4-6 somite stage. The first ten somites form at a constant rate of 2.3 somites/hr, during which time we recorded constant relative displacement of the segmental plate against the rostro-caudally elongating notochord. Unlike teleost epiboly and gastrulation, no large-scale movements of individual cells can be detected during elaboration of the embryonic axis.

Sexual development of malaria parasites is inhibited in vitro by the neem extract azadirachtin, and its semi-synthetic analogues

We have shown that azadirachtin, a compound from the neem tree, Azadirachta indica, and selected semi-synthetic derivatives, block the development of the motile male malarial gamete in vitro. Changes in the hemiacetal group at position C11 in the molecule result in a loss of activity in this assay. The motility of fully formed male gametes, and other selected flagellated cells, is unaffected by azadirachtin in vitro. These findings raise the possibility of developing azadirachtin-based compounds as antimalarials with transmission-blocking potential, as well as permitting the further study of structure-activity relationships in these compounds.

Psychodynamic Group Therapy for Older Adults: The Life Experiences Group

1. Psychodynamically oriented group psychotherapy is an effective treatment mode for older adults. The common denominator of members of the Life Experiences Group is lifelong difficulties in relationships. 2. Group goals of the Life Experiences Group are twofold: To improve interpersonal relationships through increased self-awareness and group feedback; and to enhance self-perception and attitude, and relieve symptoms through a focus on wellness within long-term illness. 3. Elders are not as vulnerable as portrayed in ageist stereotypes; they can deal with painful issues when provided with the opportunity, and they can benefit from the experience in terms of enhanced relationships and improved self-esteem.

The effect of anticholinergic bronchodilator therapy on cough during upper respiratory tract infections

1. Oxitropium bromide (Oxivent), an anticholinergic bronchodilator, inhibits coughing induced by hypotonic aerosols in both asthmatic and non-asthmatic individuals. We have now extended this work to investigate whether this antitussive activity is reproducible in cough associated with viral infection. 2. The effect of oxitropium bromide (200 micrograms three times daily) on cough and pulmonary function has been studied in 56 non-asthmatic volunteers with upper respiratory tract infections (URTI) in a double-blind, randomised, parallel group, placebo controlled study over 10 days. 3. Lung function, symptom questionnaire and cough response to ultrasonically nebulised distilled water (UNDW) inhalation were initially recorded within 72 h of development of cough and again after the 10 day treatment period. By use of a diary card at home, frequency and severity of cough, nocturnal symptoms and general malaise were assessed daily throughout the treatment period using 5 cm visual analogue scales (VAS). Peak expiratory flow rate (PEFR) was recorded thrice daily before treatment over this 10 day period. 4. VAS scores of symptoms and UNDW-induced cough frequency all decreased over the 10 days of observation whether oxitropium bromide or placebo was administered. The mean PEFR showed a statistically significant fall in morning values during the early stages of infection which lessened with recovery but no effect of treatment with oxitropium bromide was observed (P > 0.05). 5. Oxitropium bromide, which inhibits the cough response to UNDW, does not offer an effective therapy for cough associated with an upper respiratory tract viral infection.

Specific induction of intracellular calcium oscillations by complement membrane attack on oligodendroglia

Oligodendroglia (ODG) are unique among glial cell types in their capacity to activate complement in the absence of antibody, causing insertion of the potentially damaging membrane attack complex (MAC) into the plasma membrane. Using microfluorimetry of indo-1 fluorescence we have detected a complex oscillatory [Ca2+]i response in ODG following exposure to sublethal dilutions of serum-derived complement. Oscillations were transitory and preceded complete and stable return to resting [Ca2+]i levels, whereas nonoscillating ODG underwent rapid lysis. Depletion of the terminal complement component C9 from serum removed the oscillatory stimulus, which could be restored by reconstitution with purified C9. Exposure to the C9-homologous peptide melittin produced [Ca2+]i oscillations similar in pattern to those induced by whole serum. However, this type of response could not be reproduced by Ca2+ ionophores or mechanical wounding, suggesting that oscillations cannot be provoked by Ca2+ influx alone and depend on the presence of the MAC or a pore-forming lesion. Oscillations were not prevented in the continuous presence of caffeine, demonstrating independence from caffeine-releasable intracellular stores. Inhibition of the endoplasmic reticular Ca(2+)-ATPase with thapsigargin produced an abrupt elevation in [Ca2+]i but did not alter the latency between exposure to serum and the initial complement-induced transient. However, the slope of this initial transient was considerably reduced and oscillations suppressed, demonstrating dependence of the oscillatory mechanism on functional endoplasmic reticular Ca2+ stores. The coincidence of ODG recovery with oscillating [Ca2+]i suggests that the complex calcium signal that follows MAC attack may stimulate repair or protective mechanisms.

Relationship between cell adherence and proteoglycan synthesis in cultures of human peripheral blood mononuclear cells: effects of concanavalin A

Human, blood-derived mononuclear cells (MC), stimulated with Concanavalin A (Con A), synthesized a chondroitin sulfate (CS) proteoglycan (PG), which was elaborated largely by T-cells. Following Con A stimulation, the majority of MC adhered to the culture dish by day 2, but as incubation progressed to day 10 the proportion of non-adherent (NAd) MC increased in a fashion which approximately paralleled the accumulation of PG in the medium. Cell kinetic studies suggest that, following Con A stimulation, there was an inverse relationship between the amount of newly synthesized cellular PG and adherence, which appears to be related to a reciprocal effect on PG synthesis of the declining adherent (Ad) cell density with time of culture. In the stimulated cultures, NAd cells contained much more newly synthesized CS/cell than Ad cells up to day 6 of incubation. Cell type analysis, using monoclonal antibodies against specific cell surface markers, suggested that the higher PG synthesis in the NAd population may, at least in part, be due to a greater proportion of T-helper cells.

The management of renal cell carcinoma with inferior vena-caval involvement

Seven patients with renal cell carcinoma involving the inferior vena cava underwent surgical resection between 1975 and 1991. Pre-operative staging defined five patients with stage T3bNoMo disease, one patient with stage T3bN1Mo, and one patient with stage T3bNoM1 disease. At operation one patient had tumour thrombus filling the right atrium. Two patients had tumour thrombus within the intrahepatic vena cava and four infrahepatic tumour thrombus. The mean follow-up is 34.4 months (median 40 months). Four patients have been followed for over 4 years. Three of these patients are survivors, two have remained disease-free since their initial surgery. The other patient had a liver resection at 49 months for a solitary metastases; he is currently disease free. One patient died at 38 months from a gastrointestinal haemorrhage. Three patients are 12 months or less postoperation. Operative mortality was zero. The mean postoperative hospital stay was 14.7 days. Data suggests that 3-10% of renal cell carcinomas will involve the inferior vena cava. The small number of patients in this series suggests that many patients with renal cell carcinoma involving the inferior vena cava are not referred for surgical assessment. These patients are potential surgical candidates. Their survival after surgical resection, excluding the group with extension of tumour thrombus into the hepatic cava or above, is not reduced when compared with other patients with renal carcinoma.

Pharmacotherapy of bulimia nervosa--experience with fluoxetine

A number of compounds having an effect on serotonergic transmission have been shown to have a beneficial therapeutic action in patients with bulimia nervosa. Many previous studies, however, have suffered from methodological shortcomings, in particular small population sizes. This article reviews present data which suggest that fluoxetine is effective in the treatment of bulimia nervosa. Two trials of unprecedented size (n = 387 and 398, respectively) have recently been reported. These two studies show that fluoxetine, 60 mg daily, has a clear beneficial effect on behavioural and other (attitudinal) measures of bulimic symptomatology, and that this dose of fluoxetine is well tolerated in patients with bulimia nervosa. The role of pharmacotherapy in the long-term treatment of this disorder and the relative roles of pharmacotherapy and psychotherapy in treating bulimia nervosa are also discussed.

Pharmacotherapy of obsessive compulsive disorder--experience with fluoxetine

Recent epidemiological data have shown that obsessive compulsive disorder (OCD) has a lifetime prevalence of 2.5-3.0%. Compounds having an effect on serotonergic neurotransmission have demonstrated a reproducible therapeutic effect in OCD. Most recent attention has been focused on the specific serotonin re-uptake inhibitor (SSRI) class of compounds. The pooled data from two recently completed placebo-controlled studies of the SSRI, fluoxetine, have demonstrated clear evidence of a clinically valuable therapeutic effect in patients with OCD. Combined efficacy and safety data suggest that fluoxetine, 20 mg/day, will be effective in many patients. The therapeutic response emerges slowly and increases gradually. Data from extension studies suggest that, in some patients, an optimal response may only be achieved with higher daily doses of fluoxetine. Clinical response has been shown to be sustained over periods of 9 months of treatment and following withdrawal in an open-label trial. Fluoxetine is safe and well tolerated in this group of patients.

Segregation and early dispersal of neural crest cells in the embryonic zebrafish

We have exploited our ability to visualize and follow individual cells in situ, in the living embryo, to study the development of trunk neural crest in the embryonic zebrafish. In most respects, the development of zebrafish trunk neural crest is similar to the development of trunk neural crest in other species: zebrafish trunk neural crest cells segregate from the dorsal neural keel in a rostrocaudal sequence, migrate ventrally along two pathways, and give rise to neurons of the peripheral nervous system, Schwann cells, and pigment cells. However, some aspects of the development of zebrafish trunk neural crest differ from those of other vertebrates: zebrafish trunk neural crest cells are significantly larger and fewer in number than those in avian embryos and the locations of their migratory pathways are slightly different. This initial description of neural crest development in the zebrafish embryo provides the foundation for future experimental studies.

Differential effects of concanavalin A, serum and cytokines on proteoglycan elaboration and DNA synthesis by mononuclear cells from human peripheral blood

Human blood derived mononuclear cell (MC) cultures required concanavalin A (Con A) stimulation to synthesize and secrete into the medium high levels of a protease-resistant proteoglycan (PG) containing predominantly chondroitin sulfate (CS), which was elaborated largely by T-cells in culture. PG and DNA synthesis were studied in MC cultures in the absence and presence of Con A as well as serum and some biologically active polypeptide factors. In the presence of Con A, stimulation of PG synthesis was substantially greater in T-cell enriched cultures than in B-cell enriched cultures. DNA synthesis was also stimulated in the presence of Con A. This stimulation was concentration-dependent, but required the presence of serum for additional responses. DNA and cell proliferation were stimulated by interleukin-2 (IL-2), but PG production was not stimulated by conditioned media, IL-1, IL-2, IL-3, or transforming growth factor-beta (TGF-beta). Our results indicate that the elaboration of PG from T-cells of human MC is independent of the effects of regulatory peptides on cell proliferation and DNA synthesis.

A synthetic peptide corresponding to a sequence in the GTPase activating protein inhibits p21ras stimulation and promotes guanine nucleotide exchange

Amino acid sequence homology between the GTPase Activating Protein (GAP) and the GTP-binding regulatory protein, Gs alpha, suggests that a specific region of GAP primary structure (residues 891-898) may be involved in its stimulation of p21ras GTP hydrolytic activity (McCormick, F. [1989] Nature 340, 678-679). A peptide, designated p891, corresponding to GAP residues 891-906 (M891RTRVVSGFVFLRLIC906) was synthesized and tested for its ability to inhibit GAP-stimulated p21ras GTPase activity. At a concentration of 25 microM, p891 inhibited GAP activity approximately 50%. Unexpectedly, p891 also stimulated GTP binding to p21N-ras independent of GAP. This stimulation correlated with an enhancement of p21N-ras.GDP dissociation; an approximate 15-fold increase in the presence of 10 microM p891. In contrast, dissociation of the p21N-ras.GTP gamma S complex was unaffected by 10 microM p891. The p21N-ras.GDP complex was unresponsive to 100 microM mastoparan, a peptide toxin shown previously to accelerate GDP dissociation from the guanine nucleotide regulatory proteins, Gi and Go. p21H-ras, as well as the two p21H-ras effector mutants, Ala-38, and Ala-35, Leu-36, also exhibited increased rates of GDP dissociation in the presence of p891. Also tested were three ras-related GTP-binding proteins; rap, G25K and rac. The rap.-GDP complex was unaffected by 10 microM p891. Dissociation of the G25K- and rac.GDP complexes were enhanced slightly; approximately 1.3- and 1.8-fold over control, respectively. Thus, the inhibitory effect of p891 on GAP stimulation of p21ras suggests that amino acids within the region 891-906 of GAP may be essential for interaction with p21ras. In addition, p891 independently affects the nucleotide exchange properties of p21ras.

The transient expression of type II collagen at tissue interfaces during mammalian craniofacial development

Using immunocytochemical techniques, the spatiotemporal distribution of the major collagen isoform of cartilage, type II collagen, has been investigated during early craniofacial development in the mouse embryo. Early and transient expression was associated with the otic and optic vesicles, the ventrolateral surfaces of the developing brain, olfactory conchi, endocardial and mesocardial tissues, the lateral and basal surfaces of the pharyngeal endoderm and beneath the ectoderm of the branchial arches. A number of these locations are sites of epithelial-mesenchymal tissue interaction believed to generate the component parts of the chondrocranium; here, type II collagen appears transiently in advance of overt chondrogenesis in the mesenchyme. At such sites, immunofluorescence is typically localised along the basal surface of the epithelial partner, with the strongest reaction detected between the basal aspects of the otic and rhombencephalic epithelia. Immunoelectron microscopy, using pre-embedding immunostaining and a protein G-gold technique, reveals that the type II collagen is adjacent to, but not integral with, the basal laminae. Gold particles are clearly associated with 10–15 nm fibrils of the extracellular matrix in the reticulate lamina region. The pattern of type II collagen expression in the mouse closely correlates with that demonstrated previously in the quail, indicating a high degree of phylogenetic conservation between these two vertebrate species. These findings are consistent with the hypothesis that the pattern of epithelial secretion of type II collagen, or a coexpressed matrix molecule, constitutes a morphogenetic signal, realised as a matrix-mediated tissue interaction, and specifying the form of the vertebrate chondrocranium. Three-dimensional reconstruction of early type II collagen distribution, and of the subsequent chondrocranial cartilages, reveals that chondrocranial form can be derived from a ‘pre-pattern’ of epithelially derived type II collagen expressed at epithelial-mesenchymal tissue interfaces.

Administering heparin subcutaneously: an evaluation of techniques used and bruising at the injection site

This experimental study tested the effects of four different subcutaneous injection techniques on bruising at the injection site. The independent variables of aspiration of the syringe prior to injecting heparin and pressure on the site following injection, and the dependent variable of size of bruising were studied. Aspiration of the syringe had little effect on bruising. After the first injection, fewer subjects who received pressure following the injection had bruising, the difference being significant for females. However analysis of subsequent injections did not support the conclusion that pressure reduces the probability of bruising.

Kleptomania in a 13-year-old boy. A sequel of a 'lethargic' encephalitic/depressive process?

A 13-year-old boy developed severe kleptomania after a depressive illness. This was a response to psychological trauma, and appeared in the context of a probable 'lethargic' encephalitic process.

Cardiac surgery in Down syndrome

Between January 1976 and December 1987 42 children with Down syndrome and congenital heart disease underwent cardiac surgery. Four children had two operations. Age at the time of surgery ranged from 11 days to 14 years. The commonest operative procedure was repair of a patent ductus arteriosus. Four patients died post-operatively, two following repair of a complete atrio-ventricular canal defect (CAVD), one following correction of tetralogy of Fallot in association with a CAVD, and a fourth following closure of ventricular septal defect and atrial septal defect. The mortality for those who had open heart surgery was 13.3% and for the series as a whole the mortality was 6.6% over a period of follow-up ranging from two months to four years. A relatively conservative approach has been adopted with regard to surgery, based on the shorter natural expectation of life in Down syndrome, the complexity of many of the cardiac lesions involved and the recognition of the frequency of early intellectual deterioration in Down patients.

Recurrent symptoms after ventricular pacing in unexplained syncope

We report clinical and hemodynamic data in two cases of recurrent syncope. Both patients received permanent demand ventricular pacing (VVI) for unexplained syncope. Both patients experienced recurrent syncope after pacemaker implantation. They later underwent 60 degrees head-up tilt testing, initially noninvasively and then with hemodynamic profile. A vasovagal response to tilt occurred with bradycardia and was complicated by the onset of ventricular pacing and retrograde atrioventricular conduction (RAVC) with hemodynamic deterioration and rapid reproduction of syncope. Limited intracardiac electrophysiological study (EPS) excluded atrioventricular (AV) conduction disease, sinus node disease, and carotid sinus syndrome, and confirmed RAVC. Both patients were upgraded to dual chamber pacing, DDI mode, with 50/80 rate hysteresis. One patient was asymptomatic at repeat tilt testing; the other experienced continued symptoms due to the vasodepressor component of vasovagal syncope. Cardiac pacing alone is ineffective treatment for this phenomenon, and no proven therapy is presently available. Ventricular pacing applied to patients with unexplained syncope may lead to an increase in or continuation of symptoms rather than an amelioration. There is a need for full investigation of such patients, which must include tilt testing, to allow for the most accurate diagnosis possible and guide the most appropriate therapy.

Airway mucosal bioelectric potential difference in cystic fibrosis after lung transplantation

Bioelectrical potential difference (PD) across the respiratory mucosa is raised in cystic fibrosis (CF). We have recorded airway potentials from seven patients with CF who had undergone heart-lung transplantation and from eight patients without CF who had had transplants for cardiovascular disease; comparison of these populations controls for the effects of denervation and immunosuppressive treatment. Six patients without CF who had not had transplants formed an additional control. PD was recorded during routine fiberoptic bronchoscopy, using a Ringer's-perfused exploring bridge connected across a high impedance amplifier to an intravenous reference bridge. Bronchial lavage and sputum culture revealed no evidence of infection. Bronchial PD was similar in all three groups of patients at equivalent sites. However, nasal PD was raised in the CF group (mean value, 44 mV +/- 3.9 SE) compared with the patients who had transplants for cardiovascular disease (mean, 18 mV +/- 1.1 SE), and the control patients (mean, 15 mV +/- 1.2 SE). We conclude that the epithelial defects that result in raised airway potentials in CF do not recur in the transplanted lung.

Hepatitis B vaccination and GPs

Doctors seem ambivalent to their own health needs even though, when it comes to infectious diseases, their families are also at risk. This study looks at GPs' attitudes to getting themselves vaccinated against hepatitis B. Despite the risk, 21 per cent of GPs have no intention of being vaccinated.

Depressed activities of purine enzymes in lymphocytes of patients infected with human immunodeficiency virus

Enzyme activities were studied in peripheral blood lymphocytes from patients infected with, or at risk for, infection with human immunodeficiency virus (HIV). No significant differences were observed in the HIV-infected and HIV-seronegative high-risk patients with regard to enzyme activities of hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) and purine nucleoside phosphorylase (EC 2.4.2.1) in peripheral blood. Adenosine deaminase (EC 3.5.4.4) was significantly (P less than 0.02) depressed in asymptomatic HIV-seropositive patients and HIV-seronegative patients at high risk of HIV infection as compared with a healthy HIV-seronegative population. Adenosine kinase (AK, EC 2.7.1.20) was significantly increased in the asymptomatic seropositive (P less than 0.02) and also in the HIV-seronegative high-risk groups (P = 0.01) compared with the normal controls. AK activity was significantly lower in subjects with AIDS than in the asymptomatic (P less than 0.002) and high-risk groups (P less than 0.01). Taken together, these results indicate that adenosine deaminase and AK activities are influenced by the health of the patient, and that measurement of AK activity may prove useful in monitoring the clinical progress of patients with HIV infection.

Depressed activities of purine enzymes in lymphocytes of patients infected with human immunodeficiency virus

Enzyme activities were studied in peripheral blood lymphocytes from patients infected with, or at risk for, infection with human immunodeficiency virus (HIV). No significant differences were observed in the HIV-infected and HIV-seronegative high-risk patients with regard to enzyme activities of hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) and purine nucleoside phosphorylase (EC 2.4.2.1) in peripheral blood. Adenosine deaminase (EC 3.5.4.4) was significantly (P less than 0.02) depressed in asymptomatic HIV-seropositive patients and HIV-seronegative patients at high risk of HIV infection as compared with a healthy HIV-seronegative population. Adenosine kinase (AK, EC 2.7.1.20) was significantly increased in the asymptomatic seropositive (P less than 0.02) and also in the HIV-seronegative high-risk groups (P = 0.01) compared with the normal controls. AK activity was significantly lower in subjects with AIDS than in the asymptomatic (P less than 0.002) and high-risk groups (P less than 0.01). Taken together, these results indicate that adenosine deaminase and AK activities are influenced by the health of the patient, and that measurement of AK activity may prove useful in monitoring the clinical progress of patients with HIV infection.

Estradiol binding to plasma proteins after changing to a low-fat diet

Breast cancer development is believed to be associated with both dietary fat consumption and the proportion of biologically available estradiol in the serum. A study was undertaken to determine if a reduction in fat consumption would influence the binding, and thus the bioavailability, of estradiol. Groups of pre- and postmenopausal women were randomized to begin either a standard western diet (40% energy from fat) or a low-fat diet (20% energy from fat). After two months, each woman changed over to the alternate diet. Blood samples were taken at the end of each dietary period. Change of diet made no significant difference to the proportions of nonprotein-bound (free), albumin-bound, or sex hormone binding globulin-bound estradiol in this study. However, the number of women studied and the duration of change were relatively small.

Accurate measurement of airway thermal challenge

Rapid and accurate measurement of air temperature is needed to determine both heat and water losses from the respiratory tract during breathing. We have designed, constructed and validated a low dead-space, two-channel valve/mouthpiece which prevents mixing of inspired and expired air outside the body. The effects of airflow on the thermocouple response time and of thermocouple position within the airstream on the temperature measured were assessed. The 63% thermocouple response time fell from 159 to 78.8 ms as airflow rose from 23.7 to 297 1 min-1, a range including the peak flows observed while breathing at rest and during exercise. Measurement of temperature profiles across the valve/mouthpiece at different flows indicated that thermocouples were best positioned at the centre of the airstream, though small deviations did not adversely affect accuracy.

Contact guidance on microfabricated substrata: the response of teleost fin mesenchyme cells to repeating topographical patterns

The mesenchymal tissue component of the teleost pectoral fin bud has been explanted onto microfabricated quartz discs containing patterns of regular grooves of dimensions similar to those encountered by contact-guided cells in the intact fin system. Computer-aided analysis of cell migration on five separate patterns, from 1.8 to 7.4 microns repeat spacing, revealed that migration was predominantly aligned parallel to the long axis of the grooves, with individual cells becoming highly polarized, and the highest index of alignment (3.7) produced on the widest repeat spacings. When these cells are cultured on planar quartz, which is both chemically and physically isotropic, they flatten and adopt a morphology similar to that shown by cultured fibroblastic cell types on flat surfaces, suggesting that fin mesenchymal cells are not intrinsically predisposed to adopt an arborized morphology, like that observed in the intact fin bud. These results clearly demonstrate a directional migration in response to substratum topography, from a cell type known to be contact guided in vivo, and in the complete absence of adhesive heterogeneities.

Antitussive properties of inhaled bronchodilators on induced cough

We have studied the antitussive effects of two anticholinergic agents, oxitropium bromide (200 micrograms) and ipratropium bromide (80 micrograms), and a combined beta-agonist and anticholinergic preparation containing fenoterol hydrobromide (200 micrograms) and ipratropium bromide (80 micrograms), in 16 normal and ten asthmatic volunteers in a double-blind, randomized, placebo-controlled crossover trial. Cough was induced by inhalation of ultrasonically nebulized distilled water and hypotonic saline solution. All treatments significantly reduced the cough response to inhaled distilled water aerosol when compared with placebo (p less than 0.001). There was no difference between oxitropium bromide and ipratropium bromide (p greater than 0.05), but the combination preparation displayed a greater antitussive effect than either oxitropium bromide (p less than 0.05) or ipratropium bromide (p less than 0.025). Cough frequencies in response to hypotonic 0.18 and 0.32 percent saline aerosol were lower than those obtained with distilled water (p less than 0.005) for all treatments. Asthmatic patients coughed less frequently than normal volunteers in response to all solutions when placebo was given (p less than 0.05), but there is no evidence to suggest that the response to treatment was different in the two groups. Our results suggest that inhaled anticholinergic bronchodilators alone or in combination with beta 2-adrenergic agonists might be effective in the treatment of pathologic cough.

Teleost epiboly: a reassessment of deep cell movement in the germ ring

Using the prominent cell nucleus as an intrinsic marker, individual deep cell blastomeres have been monitored in vivo using Nomarski differential interference contrast microscopy during spreading of the teleost blastoderm. Involution of these cells has been recorded during early to mid stages of epiboly about an apparent point of shear located centrally within the germ ring. This involuting movement involves superficial deep cells, adjacent to the enveloping layer, as well as those located more centrally within the germ ring and is associated with a continuous vegetal displacement of the outer strata of deep cell blastomeres towards the edge of the blastodisc. During the early stages of epiboly this process is qualitatively similar at any location around the entire circumferential margin of the blastodisc. Postinvoluting deep cells are found close to the yolk syncytial layer, are surrounded by considerable intercellular space and illustrate less directional displacement. In contrast to the deep cell layer, the enveloping layer was never observed to invaginate. These results contradict the current view that no involution or global rearrangement of deep cells occurs during teleost gastrulation and present the first direct evidence of involution within the deep cell population during early epiboly.

Modification by pertussis toxin of the responses of bovine anterior pituitary cells to acetylcholine and dopamine: effects on hormone secretion and 86Rb efflux

Acetylcholine is known to stimulate the secretion of growth hormone and prolactin and the efflux of 86Rb from bovine anterior pituitary cells: dopamine prevents the stimulation of 86Rb efflux and of prolactin but not growth hormone secretion. The sensitivity of these responses to pertussis toxin has been determined. Treatment of bovine anterior pituitary cells in primary culture with pertussis toxin (18 h, 100 ng/ml) did not modify the stimulation of prolactin secretion by acetylcholine, but prevented its inhibition by dopamine. In lactotrophs, dopamine but not acetylcholine receptors are therefore coupled to secretion through a pertussis toxin substrate. The stimulation of 86Rb efflux by acetylcholine was also unaffected by pertussis toxin and, again, its inhibition by dopamine was prevented. Treatment of the cells with pertussis toxin enhanced the secretion of growth hormone in response to acetylcholine. Nitrendepine (1 mumol/l) prevented the cholinergic stimulation of growth hormone but not prolactin secretion from these cells. Acetylcholine increased the cytoplasmic calcium concentration and this rise was enhanced by treatment of the cells with pertussis toxin. Nitrendepine partially inhibited the rise in calcium caused by acetylcholine, and prevented the enhancement of the rise following pertussis toxin treatment. Cholinergic stimulation of growth hormone therefore depends on calcium entry through nitrendepine-sensitive channels, whereas stimulation of prolactin secretion does not, and in somatotrophs a pertussis toxin substrate may limit calcium entry through these channels. These different sensitivities of somatotrophs and lactotrophs to pertussis toxin and nitrendepine may reflect differences in the properties of the predominant calcium currents in the two cell types.

An ultrastructural and morphometric analysis of an in vivo contact guidance system

The pectoral fin bud of the developing teleost embryo contains a highly ordered extracellular matrix of collagenous fibrils, called ‘actinotrichia’. During invasion of the fin fold, mesenchymal cells, migrating distally from the base of the fin, become contact aligned by the actinotrichial fibrils. Behavioural aspects of this response have previously been studied using Nomarski differential interference contrast microscopy and time-lapse video recording (Wood & Thorogood, 1984). Here we present an ultrastructural description of these cells and their matrix associations and a computer- based morphometric analysis of selected parameters within the migration substratum, relevant to this in vivo ‘contact guidance’ phenomenon. The study shows that a differentiated and aligned matrix of actinotrichial fibrils can be detected before invasion of the fin fold, at levels up to 40μm distal to the advancing mesenchymal cell margin. Subsequently, during invasion of the fin fold, aligned mesenchymal cells and processes are almost exclusively associated with actinotrichia and not the intervening surface of the epithelial basal lamina. However, aligned cell processes appear to avoid the smaller actinotrichia and at late stages of development 87á0% of actinotrichia without cell process contacts are distributed at the lower end of the size range. Study of cell ultrastructure revealed a complete absence of cytoskeletal organization within this mesenchymal cell population, although cytoskeletal components are clearly visible in adjacent epithelia. The computer-based morphometric survey of the migration substratum has shown a gradual but progressive increase in the mean diameter of actinotrichia at a level at which distal cell processes are first detectable in sections of fins. However, at similar levels over the same period the mean value for interactinotrichial spacings remained virtually constant. These results suggest that the spacing between actinotrichia is not significant in contributing to progressive changes in mesenchymal cell phenotype, but that the actinotrichia themselves are strongly implicated in providing the guidance cues to direct cell migration within the developing fin and the initiation of cell migration. These findings are discussed in the general context of cell movement and contact guidance both in vivo and in vitro.

Comparison of the stimulation of glycosaminoglycan synthesis in cultures of mononuclear cells from blood and of fibroblastic cells

A small molecular weight factor, derived from bovine bone ('matrigenin'), stimulated glycosaminoglycan and proteoglycan synthesis of cultured human fibroblastic cells but not of mononuclear cells from human blood. However, proteoglycan synthesis and secretion by the mononuclear cells was stimulated by the addition of concanavalin A. The proteoglycan from the concanavalin-A-stimulated mononuclear cells was of smaller molecular weight than the proteoglycan from the 'matrigenin'-stimulated fibroblastic cells. The major increase in proteoglycan synthesis and secretion occurred much later during the culture period for concanavalin-A-stimulated mononuclear cells than for 'matrigenin'-stimulated fibroblastic cells.

Antisera to the variable region of ras oncogene proteins, and specific detection of H-ras expression in an experimental model of chemical carcinogenesis

Antisera were prepared in mice, rats and rabbits by immunization with peptides corresponding to regions of highest variability, located near the C-termini of four ras proteins. Two of these, H-ras (171-189) and K-rasB (171-186), react uniquely with H-ras and K-rasB gene products in immunoblots and immunoprecipitation reactions. Affinity-purified rabbit H-ras (171-189) antibody detects H-ras p21 in tissue culture cells and in tissue sections. Epithelial cells in normal mouse skin and cells in papillomas and carcinomas, in a mouse model system of chemical carcinogenesis in which mutational activation of H-ras occurs with high frequency, express high levels of H-ras p21 protein. These results suggest an hypothesis to explain the mechanism and preferential activation of particular ras loci in certain neoplasia.

Analysis of in vivo cell movement using transparent tissue systems

The embryos of certain teleost species are transparent and cell behaviour within the intact embryo can be observed and recorded using Nomarski microscopy coupled with time-lapse video recording or time-lapse cine filming. In this report we review some of our recent analyses of cell behaviour patterns underlying key morphogenetic events. (1) Contact-guided cell migration through a structurally ordered extracellular matrix during fin development; (2) movement of tissue layers during epibolic overgrowth; and (3) cell 'social' behaviour during the establishment of the body axis (i.e. notochord formation and somitogenesis). These results, on cell behaviour correlated with normal morphogenesis, provide a baseline for further work in which hypotheses concerning subcellular and molecular controls of cell behaviour can be tested by experimental perturbation in vivo.

Immunochemical recognition of phosphate ester derivatives of phenol rings is dependent upon the electronic charge of the ester group

The recognition of phosphate and sulphate esters of tyrosine residues has been studied employing antisera with specificity for tyrosine phosphate, and the enzymes aryl sulphatase, and acid and alkaline phosphatases. The ability of tyrosine phosphate, and of phosphate esters of phenol, to inhibit the antiserum was pH dependent. The capacity to effect inhibition appeared to correlate with alterations in the ionisation of the inhibitor. Moreover, the antisera with reactivity for tyrosine phosphate had no reactivity with tyrosine sulphate or sulphate esters of phenol at any pH value studied. The enzymes alkaline phosphatase, acid phosphatase, and aryl sulphatase were also studied. The phosphatases were found not to hydrolyse sulphate ester containing substrate analogues at any pH value in the range 5.0-9.0. In contrast, aryl sulphatase appeared to hydrolyse phosphate esters at pH 5.0 and 7.0, but not at pH 9.0.

Microbial flora of the eyes of cattle

The bacteria and mycoplasma occurring in the eyes of normal healthy calves were monitored in three groups of animals from purchase at about one week old to slaughter at about 15 months old. Non-haemolytic Moraxella bovis, Branhamella catarrhalis and Mycoplasma bovoculi were all isolated regularly, though their seasonal occurrence varied. The significance of these findings with respect to infectious bovine keratoconjunctivitis is discussed.

Effects of conditioned medium upon proliferation, deoxynucleotide metabolism, and antimetabolite sensitivity of promyelocytic leukemic cells in vitro

In order to investigate the interaction of factors from leukocyte-conditioned medium with leukemic cells, effects of an ammonium sulfate-precipitated conditioned medium concentrate were tested upon HL-60 cells. This preparation increased tritiated thymidine incorporation into DNA of HL-60 cells markedly, an effect which was found to be attributable in large part to greater thymidine accumulation in the intracellular nucleotide triphosphate pool. A modestly expanded population of DNA synthetic phase cells was also demonstrated by flow cytometry. Similar effects were noted of the K562 and KG-1 cell lines and were also demonstrable with giant cell tumor-conditioned medium. These effects were not demonstrable with a purified preparation of granulocyte-monocyte colony-stimulated factor. Because of the altered pattern of nucleotide metabolism noted, the effect of the conditioned medium concentrate upon 5-fluorouracil sensitivity was tested. Following continuous 24-h exposure to 5-fluorouracil at 5 X 10(-6) M, tritiated thymidine incorporation of HL-60 cells increased in parallel with depletion of endogenous thymidylate. Conditioned medium concentrate markedly sensitized cells to this effect of 5-fluorouracil and also increased growth retardation, cytotoxicity, and cell cycle arrest as assessed by flow cytometry. These studies thus demonstrated marked effects of a factor in conditioned medium on deoxynucleotide uptake and metabolism of the HL-60 line. These effects occurred in conjunction with, but were relatively more marked than, effects upon cell cycle distribution and were found to influence chemotherapy sensitivity.