The effect of inositol 1,3,4,5-tetrakisphosphate on inositol trisphosphate-induced Ca2+ mobilization in freshly isolated and cultured mouse lacrimal acinar cells

Earlier reports have shown a remarkable synergism between InsP(4) and InsP(3) [either Ins(1,4,5)P(3) or Ins(2,4,5)P(3)] in activating Ca(2+)-dependent K(+) and Cl(-) currents in mouse lacrimal cells [Changya, Gallacher, Irvine, Potter and Petersen (1989) J. Membr. Biol. 109, 85-93; Smith (1992) Biochem. J. 283, 27-30]. However, Bird, Rossier, Hughes, Shears, Armstrong and Putney [(1991) Nature (London) 352, 162-165] reported that they could see no such synergism in the same cell type. A major experimental difference between the two laboratories lies in whether or not the cells were maintained in primary culture before use. Here we have compared directly the responses to inositol polyphosphates in freshly isolated cells versus cells cultured for 6-72 h. In the cultured cells, Ins(2,4,5)P(3) at 100 microM produced a robust stimulation of K(+) and Cl(-) currents, as much as an order of magnitude greater than that observed in the freshly isolated cells. However, the freshly isolated cells could be restored to a sensitivity similar to cultured cells by the addition of InsP(4) at a concentration two orders of magnitude lower than that of Ins(2,4,5)P(3). We discuss the implications of this with respect to the actions of InsP(4), including the possibility that disruption of the cellular structure during the isolation of the cells exposes an extreme manifestation of a possible physiological role for InsP(4) in controlling calcium-store integrity.

Quantitation of virus-specific classes of antibodies following immunization of mice with attenuated equine herpesvirus 1 and viral glycoprotein D

The antibody responses of CBA/J mice infected intranasally (i.n.) with either the attenuated KyA strain or the pathogenic RacL11 strain of equine herpesvirus 1 (EHV-1) or immunized with recombinant glycoprotein D (rgD) were investigated using the ELISPOT assay to measure EHV-1-specific antibody-secreting cells (ASC) in the regional lymphoid tissue of the respiratory tract. IgG, IgA, and IgM ASC specific for EHV-1 were detected in the mediastinal lymph nodes (MLN) and lungs 2 weeks after i.n. infection with EHV-1 strain KyA or RacL11, or immunization with heat-killed KyA or rgD. EHV-1-specific ASC were present in the MLN and lungs at 4 and 8 weeks, but declined in frequency by fivefold in the lung at 8 weeks. However, i.n. immunized (2 x 10(6) pfu KyA or 50 microgram rgD/mouse) mice infected at 8 weeks with pathogenic EHV-1 RacL11 resisted challenge and showed eight- and tenfold increases in MLN ASC and lung ASC, respectively, by 3 days after challenge. In contrast to the intranasal route of immunization, intraperitoneal immunization yielded ASC frequencies in the MLN and lungs that were only slightly above those of nonimmunized control mice. These data indicate that immunization with infectious or heat-killed EHV-1 KyA, or rgD, induces significant levels of virus-specific ASC both in the MLN and lungs, a specific memory B-cell response, and long-term protective immunity. The finding that the numbers of ASC induced by the pathogenic strain versus the attenuated strain of EHV-1, which were virtually identical, indicated that the ability to generate a B-cell response is independent of and does not contribute to EHV-1 virulence.

Incidence and presentation of coeliac disease in South Glamorgan

OBJECTIVE

To determine the incidence and presenting features of coeliac disease and dermatitis herpetiformis in the population of South Glamorgan between 1981 and 1995.

DESIGN

Retrospective case-finding study using pathology, dietetic and clinical records, data from hospital activity analysis, general practice records and a Coeliac Society questionnaire. Incidence rates were calculated using the Registrar General's mid-year estimates.

SETTING

Regional hospitals, South Glamorgan, Wales.

PARTICIPANTS

All new cases of coeliac disease or dermatitis herpetiformis.

MAIN OUTCOME MEASURES

Crude incidence rates (per quinquennia) for both children and adults. Age, sex, family history, symptoms at the time of diagnosis and time to diagnosis from symptom onset.

RESULTS

In total, 137 cases of coeliac disease (27 children, 110 adults) and 19 cases of dermatitis herpetiformis were detected. In adults with coeliac disease, incidence rates have risen from 1.32 to 3.08 per 100,000 with a 3:1 female predominance. Almost 50% of adults were over fifty years old when diagnosed and 25% had no abdominal symptoms. In children, the disease incidence has remained stable but with a rising trend in mean age at diagnosis and higher likelihood of atypical symptoms in older children. There has been no change in the incidence of dermatitis herpetiformis. Only 8.3% of all patients had an affected first-degree relative.

CONCLUSIONS

In contrast to other reports of declining incidence, coeliac disease in children has remained constant in South Glamorgan, but has markedly increased in adults, particularly women. Presentation may be at any age, often with atypical symptoms, which may delay diagnosis.

Public support for medical research in the 21st century

Key public policies that have contributed to the rise of modern medical research in the 20th Century are reviewed, focusing especially on the United States and the post-World War II period. Drawing on this history, the question is posed: "Are these policies sufficient to insure vigorous medical research in the 21st Century?" Although radical policy changes are not needed, several proposals for policy and medical research portfolio redirection are offered, including a rebalancing of public supported research in all fields of science that contribute to medical advances. Medical research must also invest in a national and international information infrastructure that will allow the linking of researchers, clinical experimenters, practicing physicians, and the public in ways heretofore not imagined. Medical researchers must be leaders and advocates for the whole research enterprise in the 21st Century.

Room at the top?

Nurse executives have joined hospital administrative teams, but are they accepted as fully integrated team executives? Learn how nurse executives and their influential colleagues view integration and its influences.

Morphological and functional characteristics of acinar atrophy and recovery in the duct-ligated parotid gland of the rat

Although acinar atrophy occurs frequently in salivary diseases, the relationship between structural changes and functional decrements is not well-established, and the potential for recovery of histological and functional integrity has not been wholly quantified. We aimed, therefore, to develop further our understanding of pathological acinar atrophy. Stensen's duct was ligated for periods up to six weeks and, in separate experiments, was de-ligated after two weeks and allowed to recover for up to two weeks. Qualitative and quantitative histological analyses were carried out. Additionally, the ability of enzymatically dispersed cells from ligated and de-ligated glands to respond to neurohormonal stimuli was also measured. The results confirmed that totally obstructed glands undergo a rapid, progressive severe atrophy amounting to absolute losses of over 85% of acinar tissue by two weeks. Acinar shrinkage and cell losses through apoptosis accounted for the glandular atrophy. Remaining intralobular epithelia consisted of extremely atrophic acini and numerous duct-like structures with intermediate forms. Dispersed cells from atrophic glands exhibited agonist-induced release of chloride similar to normal. Together, these structural-functional results confirm the persistent viability of acinar-like cells in the obstructed gland and suggest that the duct-like structures are derived from surviving atrophic acini. De-ligated glands exhibited a near-normal recovery of structure by two weeks. Their enzymatically dispersed cells responded normally to agonist stimulation. The results support the view that pathological atrophy is largely similar to physiological atrophy, providing a mechanism for acinar cell survival under adverse conditions, with the possibility of eventual recovery.

Tissue transglutaminase antibodies in celiac disease

OBJECTIVE

Tissue transglutaminase is the antigen for antiendomysial antibodies, whose power in screening for celiac disease is well known. Our aim was to assess the efficacy of an ELISA assay for tissue transglutaminase antibodies.

METHODS

Tissue transglutaminase antibodies were analyzed in serum from 39 untreated celiac disease patients and 61 controls. Tissue transglutaminase was used as antigen, and test sera analyzed by ELISA. Results higher than 0.6 optical density were considered positive, lower than 0.4 negative, and between 0.4 and 0.6 borderline.

RESULTS

Optical density of the serum from the patients with untreated celiac disease (median: 1.41; range: 0.33-1.47) were significantly higher than the controls (median: 0.32; range: 0.17-0.68; p < 0.0001; 95% confidence interval 0.87-1.08). Thirty-three patients with untreated celiac disease were positive, 4 borderline, and 2 negative. Fifty-five controls were negative, 4 borderline, and 2 positive. If we consider borderline results to be positive, sensitivity is 94.8% and specificity 90.1%. None of the controls gave results higher than 0.7 optical density. Apart from the 2 negative patients with untreated celiac disease, the two groups overlapped only between 0.4 and 0.7 optical density.

CONCLUSIONS

Because of the high sensitivity (approximately 95%) and technical simplicity, tissue transglutaminase antibodies may prove useful for the screening of celiac disease in population at low or medium risk of celiac disease. To avoid duodenal biopsies in patients without celiac disease, the specificity of the screening procedure may be increased by confirming with antiendomysial antibodies by immunofluorescence on human umbilical cord in individuals with results between 0.4 and 0.7 optical density.

Control of neuronal excitability by an ion-sensing receptor (correction of anion-sensing)

While most central nervous system (CNS) neurons receive the majority of their input through direct synaptic connections, there is evidence suggesting that they are in fact susceptible to modulation by changes in extracellular ionic composition during both physiological and pathophysiological conditions. In many regions of the CNS, there exists an identified extracellular receptor with the ability to sense levels of cations, most notably calcium. Here we report that activation of this calcium receptor (CaR) in neurons of the subfornical organ (SFO), a forebrain circumventricular structure, results in profound effects on neuronal excitability through metabotropic actions on a non-selective cation channel. Activation of the CaR by NPS R-467, an allosteric agonist of the CaR, evoked depolarizing plateau potentials ranging in duration from 5 to 30 s. Similarly, 5 mm CaCl2 caused depolarization and increased action potential frequency. NPS R-467 was found to activate a non-selective cation channel with a reversal potential of -48 +/- 4 mV, and a slope conductance of 2.54 +/- 11 nS. This current could also be elicited by spermine, a known agonist of the CaR. CaR-mediated activation of this channel was dependent upon both G proteins and intracellular Ca2+ signalling, as disruption of these pathways through inclusion of guanosine 5'-O-(2-thiodiphosphate) (GDP-beta-S) and 1,2-bis(2-aminophenoxy)ethane-N,N,N ',N '-tetraacetic acid (BAPTA), respectively, in the recording pipette prevented activation of the current. Microinjection of CaR agonists into the SFO of anaesthetized rats resulted in a significant, site-specific elevation of blood pressure (mean area under curve, 141 +/- 50 mmHg. s). Together, these results indicate that the CaR can play an important role in transducing the effects of changes in the extracellular ionic composition, and that these effects have implications for the neural control of fluid balance.

Academic preparation for healthcare executive-track personnel

This study focuses on career aspirations of executive-track health care administrative personnel and their perceptions of the competencies required to become hospital chief executive officers (CEOs). This article examines these topics using the results of a 1994 survey of 162 junior- and mid-level healthcare managers who work in hospitals in a western state. Respondents included 34 CEO aspirants and 128 CEO nonaspirants. The majority of both groups reported high satisfaction with several work-related activities. Significantly more CEO nonaspirants than CEO aspirants perceived a need for additional self-development in several work areas. CEO aspirants reported that CEOs five years from now would need improved strategy formulation and negotiation skills. CEO aspirants also perceived that in the future, successful CEOs will have to be more proficient in several areas, such as interpersonal skills and medical staff relations. Three lists of academic subject matter considered important to career preparation were generated from (1) the Association of University Programs in Health Administration (AUPHA) undergraduate standards, combined with curriculum graduate standards of the Accrediting Commission on Education for Health Services Administration (ACEHSA); (2) study participants' responses; and (3) professional literature. When compared for relatedness, the contents of the three lists were not significantly different statistically. The implications of these findings for health administration education are discussed.

In-hospital smoking cessation programs: who responds, who doesn't?

This study extends the results of a large randomized clinical trial of a multicomponent in-hospital smoking cessation intervention for general hospitalized smokers by examining subgroups of patients who responded to the intervention. The results, obtained using signal detection analysis, produced 6 subgroups of patients with varying degrees of intervention responsiveness. The subgroup most responsive was marked by 100% confidence to quit smoking at baseline. Among patients with less than 100% confidence, confidence interacted with age, depressed mood scores, addiction scores, and alcohol intake to discriminate 5 additional subgroups. Discussion focuses on how this information can be used in clinical decision making to treat subpopulations of smokers and directs attention to possible areas of underlying biopsychosocial processes that may interact to affect successful long-term cessation.

In-hospital smoking cessation programs: who responds, who doesn't?

This study extends the results of a large randomized clinical trial of a multicomponent in-hospital smoking cessation intervention for general hospitalized smokers by examining subgroups of patients who responded to the intervention. The results, obtained using signal detection analysis, produced 6 subgroups of patients with varying degrees of intervention responsiveness. The subgroup most responsive was marked by 100% confidence to quit smoking at baseline. Among patients with less than 100% confidence, confidence interacted with age, depressed mood scores, addiction scores, and alcohol intake to discriminate 5 additional subgroups. Discussion focuses on how this information can be used in clinical decision making to treat subpopulations of smokers and directs attention to possible areas of underlying biopsychosocial processes that may interact to affect successful long-term cessation.

General Green's functions for SAW device analysis

The traditional Green's function has been widely used to analyze surface acoustic wave (SAW) devices for many years because of its physical basis and its ability to model many propagating modes. Simplifications are, however, introduced in the derivation of the traditional Green's function that cause it to ignore some important effects, such as mass loading caused by surface electrodes. Recently, a generalized Green's function was introduced that is able to include mechanical loading effects. Based on previous work by E.L. Adler (1994) and R.C. Peach (1995), we use concise matrix notation to deduce the generalized Green's functions that describe the effects of surface stresses and electrical displacement on the three mechanical displacement components and on the electrical potential. Effective permittivities of 15 materials/cuts and the 16-element Green's functions for two materials are presented.

Leptin acts in the rat hypothalamic paraventricular nucleus to induce gastric mucosal damage

Leptin is produced and secreted by adipocytes to regulate body weight homeostasis. Leptin acts centrally to reduce weight by decreasing food intake and increasing energy expenditure. The paraventricular nucleus (PVN) is a central nervous system structure suggested as a site at which leptin acts to exert its central effects. Leptin microinjection (10(-6) M, 0.5 microl) into the PVN of urethan-anesthetized male Sprague-Dawley rats (150-300 g) resulted in significant gastric damage (mean score = 1.75, n = 16). Damage scores were significantly different than those observed after saline microinjection into the PVN (mean score = 0.00, n = 5, P < 0. 05), or leptin microinjection into non-PVN sites (mean score = 0.33, n = 6, P < 0.05). There were no changes in blood pressure (mean area under curve = 401.9 +/- 224.2 mmHg * s, n = 11, P > 0.05) or heart rate (mean area under curve = 40.9 +/- 25.9 beats, n = 10, P > 0.05) in response to leptin microinjection into PVN. These results suggest that leptin acts on a functionally specific population of PVN neurons involved in the control of gastrointestinal function.

Protective immunity against equine herpesvirus type-1 (EHV-1) infection in mice induced by recombinant EHV-1 gD

The ability of recombinant preparations of equine herpesvirus type 1 (EHV-1) glycoprotein D (gD) to elicit specific antibody and T lymphocyte responses in the BALB/c mouse model of respiratory infection was investigated. Recombinant gD (rgD) expressed as a glutathione-S-transferase (GST) fusion protein in Escherichia coli elicited both high titer neutralizing antibody (nAb) and CD4 T cell proliferative responses following subcutaneous or intranasal immunization, but elicited only a weak antibody response after intraperitoneal immunization. Protection against respiratory tract infection with pathogenic EHV-1 RacL11 was observed in mice immunized subcutaneously with GST-gD. Furthermore, the degree of protection correlated to the titer of nAb and the T cell response observed. Finally, GST-gD was more effective in protecting against respiratory RacL11 infection if delivered intranasally. These results confirm that gD plays an important role in eliciting the protective immune response against EHV-1 infection, and indicate that subunit vaccines containing preparations of gD may be very effective if delivered directly to the upper respiratory tract.

A comparison of barium swallow and erect esophageal transit scintigraphy following balloon dilatation for achalasia

We evaluated the relationship between radionuclide esophageal transit studies and barium swallow appearances in a group of patients following forceful balloon dilatation for the treatment of achalasia of the cardia. Paired erect radionuclide esophageal transit studies and erect barium swallows of a group of patients who had undergone pneumatic balloon dilatation for the treatment of achalasia were analyzed. Indices derived from the radionuclide transit study were the percentage of maximum activity remaining in the esophagus 30 s after swallowing a dilute volume of tracer (A30 s) and the percentage of retained activity remaining at 100 s after washout with a bolus of water (A100 s). Indices derived from the barium swallow were a subjective grading of the degree of esophageal dilatation on a 4-point scale and a similar grading of the maximum distensibility of the gastroesophageal channel. Twenty five pairs of radionuclide and barium studies in 18 patients were analyzed. There was statistically significant correlation between the amount of retained activity on the radionuclide studies and degree of esophageal dilatation on the barium studies (r = 0.69 for A30 s, r = 0.56 for A100 s, P = < 0.01). There was no correlation between the amount of retained activity on the radionuclide studies and the degree of distension of the gastroesophageal channel on barium studies. The relationship between the radionuclide esophageal transit curve and barium appearances of the esophagus following pneumatic balloon dilatation for the treatment of achalasia is complex. The transit study provides unreliable information about the distensibility of the gastroesophageal channel and should not be relied upon in isolation for assessment of the efficacy of treatment.

Characterization of the cytolytic T-lymphocyte response to a candidate vaccine strain of equine herpesvirus 1 in CBA mice

The cytolytic T-lymphocyte (CTL) response to respiratory infection with equine herpesvirus 1 (EHV-1) in CBA (H-2(k)) mice was investigated. Intranasal (i.n.) inoculation of mice with the attenuated EHV-1 strain KyA resulted in the generation of a primary virus-specific CTL response in the draining mediastinal lymph nodes 5 days following infection. EHV-1-specific CTL could be restimulated from the spleen up to 26 weeks after the resolution of infection, indicating that a long-lived memory CTL population was generated. Depletion of CD8+ T cells by treatment with antibody and complement prior to assay eliminated CTL activity from both primary and memory populations, indicating that cytolytic activity in this model was mediated by class I major histocompatibility complex-restricted, CD8+ T cells. A single i.n. inoculation with KyA induced protective immunity against infection with the pathogenic EHV-1 strain, RacL11. The adoptive transfer of splenocytes from KyA-immune donors into sublethally irradiated recipients resulted in a greater than 250-fold reduction in RacL11 in the lung. The elimination of both CD4+ and CD8+ T cells from the transferred cells abrogated clearance of RacL11, while the selective depletion of either subpopulation alone had little effect. These results suggested that both lymphocyte subpopulations contribute to viral clearance, with either subpopulation alone being sufficient.

AIR synthetase in cowpea nodules: a single gene product targeted to two organelles?

A cDNA (VUpur5) encoding phosphoribosyl aminoimidazole (AIR) synthetase, the fifth enzyme of the de novo purine biosynthesis pathway has been isolated from a cowpea nodule cDNA library. It encodes a 388 amino acid protein with a predicted molecular mass of 40.4 kDa. The deduced amino acid sequence has significant homology with AIR synthetase from other organisms. AIR synthetase is present in both mitochondria and plastids of cowpea nodules. A signal sequence encoded by the VUpur5 cDNA has properties associated with plastid transit sequences but there is no consensus cleavage site as would be expected for a plastid targeted protein. Although the signal sequence does not have the structural features of a mitochondrial targeted protein, it has a mitochondrial cleavage site motif (RX/XS) close to the predicted N-terminus of the mature protein. Southern analysis suggests that AIR synthetase is encoded by a single gene raising questions as to how the product of this gene is targeted to the two organelles. VUpur5 is expressed at much higher levels in nodules compared to other cowpea tissues and the gene is active before nitrogen fixation begins. These results suggest that products of nitrogen fixation do not play a role in the initial induction of gene expression. VUpur5 was expressed in Escherichia coli and the recombinant protein used to raise antibodies. These antibodies recognize two forms of AIR synthetase which differ in molecular size. Both forms are present in mitochondria, although the larger protein is more abundant. Only the smaller protein was detected in plastids.

Intracellular calcium signalling in rat parotid acinar cells that lack secretory vesicles

Secretory vesicles from pancreatic acinar cells have recently been shown to release Ca2+ after stimulation with Ins(1,4,5)P3 [Gerasimenko, Gerasimenko, Belan and Petersen, (1996) Cell 84, 473-480]. These observations have been used in support of the hypothesis that Ca2+ release from secretory vesicles could be an important component of stimulus secretion coupling in exocrine acinar cells. In the rat, ligation of the parotid duct causes a reversible atrophy of the parotid gland. Most notably, after atrophy the acinar cells are reduced in size and no longer contain secretory vesicles [Liu, Smith, and Scott (1996) J. Dent. Res. 74, 900]. We have measured cytosolic free-Ca2+ concentration ([Ca2+]i) in single, acutely isolated, rat parotid acinar cells, and compared Ca2+ mobilization in response to acetylcholine (ACh) stimulation in cells obtained from control animals to that in cells lacking secretory vesicles obtained after atrophy of the parotid gland. Application of 50-5000 nM ACh to control cells gave rise to a typical, dose-dependent, biphasic increase in [Ca2+]i, of which the later, plateau, phase was acutely dependent on the extracellular Ca2+ concentration. An identical pattern of response was observed with cells obtained from atrophic glands. Low concentrations of ACh (10-100 nM) occasionally produced [Ca2+]i oscillations of a similar pattern in cells from both control and atrophic glands. We were able to show that Ca2+ rises first in the apical pole of the cell and the increase then spreads to the rest of the cell in cells from control glands but not in cells from atrophic glands. However, at present we are unable to determine whether this is due to the lack of secretory vesicles or whether the separation is too small to measure in the smaller acinar cells obtained from atrophic glands. We conclude therefore, that secretory vesicles make no significant contribution to overall Ca2+ mobilization in rat parotid acinar cells, nor are they required for oscillatory changes in [Ca2+]i to occur. However we are unable to eliminate completely any role for secretory vesicles in initiating Ca2+ mobilization at the apical pole of the cell.

Analysis of the passband ripples in surface acoustic wave IIDT filters

A computer simulation, based on the quasistatic Green's function model, of the passband ripples in interdigitated interdigital transducer filters is presented. Multiple-transit echo signals and electrode interactions, under the condition of poorly matched external circuits, are included in the model. A variation on the IIDT structure that suppresses the ripples is proposed.

Hospital administrators' career paths: which way to the top?

This article examines career paths of aspirants to hospital administrator positions. It focuses on successful career objectives, barriers, and paths. The 1994 survey data from 162 hospital-employed executive track personnel in a western state facilitate comparisons with nonaspirants. Only 34 (21 percent) self-reported a goal to become an administrator. Aspirants require institutional and mentor support, and need to follow more proactive and diverse career paths than they have done previously.

Identification of a Ca2+ binding protein as a new Bermuda grass pollen allergen Cyn d 7: IgE cross-reactivity with oilseed rape pollen allergen Bra r 1

cDNA clones encoding two isoforms of an allergen from pollen of Bermuda grass (Cynodon dactylon) have been isolated using IgE from allergic patients. Homologous transcripts are present in pollen of 15 other grasses tested. This allergen, tentatively designated as Cyn d 7, contains two calcium binding domains and shows significant sequence similarity with other Ca2+ binding pollen allergens, namely Bet v 4 from birch and Bra r 1 from oilseed rape. Approximately 10% of allergic sera tested showed IgE reactivity to this allergen. IgE cross-reactivity was observed between this allergen and Bra r 1 of oilseed rape. IgE reactivity of this allergen requires protein-bound Ca2+. Using IgE affinity-purified from the recombinant allergen to probe Western blots of pollen extracts Cyn d 7 has been identified as a 12 kDA protein.

Long duration pressor responses following activation of subfornical organ neurons in rats are the result of increased circulating vasopressin

Electrical stimulation in the subfornical organ (SFO) of male Sprague-Dawley rats resulted in biphasic increases in blood pressure (BP) without a change in heart rate. The initial short duration (0-10 s) increase in BP lasted throughout the 10 s stimulation period (area under the curve (AUC) = 104.3+/-15.26 mmHg/s, (mean+/-SEM) P < 0.001). Upon termination of the electrical stimulus, the BP remained elevated for approximately 55 s (long duration response, AUC = 327.5+/-48.22 mmHg/s, P < 0.001). This long duration BP response was determined to be the result of an increase in circulating vasopressin (VP) as administration of a V1 receptor antagonist abolished this response (AUC = -210.7 +/- 42.38 mmHg/s, P < 0.01). The results of the present study demonstrate that the long duration component of the biphasic increase in BP observed on response to electrical stimulation of the SFO is the result of increased concentrations of circulating VP.

Vasopressin acts in the subfornical organ to decrease blood pressure

In addition to its traditional role as a circulating vasoactive peptide, vasopressin (VP) has been shown to play significant roles in central cardiovascular processing. The recent description of VP receptors within the subfornical organ (SFO) has suggested this circumventricular organ (CVO) as a potential locus for feedback actions of circulating VP on the brain. The well-established anatomical connections between SFO and hypothalamic autonomic control centers provide further arguments in support of such a view. This study was undertaken to determine the physiological consequences of activation of VP receptors within the SFO of urethane anesthetized rats. Microinjection (0.5 microliter) of 5 pmol VP into SFO resulted in significant decreases in blood pressure (BP, mean AUC -638.3 +/- 110.3 mm Hg.s, p < 0.01, n = 13) without a change in heart rate (HR, mean AUC 7.9 +/- 14.0 beats, p > 0.05, n = 12), effects which were repeatable. These depressor effects were specific to microinjection locations within this CVO as similar VP microinjections into non-SFO tissue were without effect on BP (mean AUC 245.4 +/- 111.5 mm Hg.s, p > 0.05, n = 10), or HR (mean AUC 1.8 +/- 3.1 beats, p > 0.05, n = 9). In contrast to the former depressor effects, VP microinjection (5 pmol in 0.5 microliter) into the third ventricle produced large increases in BP (mean AUC 1,461.8 +/- 368.97 mm Hg.s, p < 0.05, n = 6) again with no change in HR (mean AUC 1.4 +/- 5.96 beats, p > 0.05, n = 6). The hypotensive effects observed in response to VP microinjection into SFO were abolished by systemic treatment with a V1 receptor antagonist (mean AUC 89.5 +/- 67.7 mm Hg.s, p > 0.05) compared to BP response before V1 receptor blockade (mean AUC -605.9 +/- 119.8 mm Hg.s, n = 4). These results suggest that the SFO may be an essential structure in the feedback control loop through which circulating VP influences descending autonomic pathways involved in cardiovascular control.

Adrenomedullin microinjection into the area postrema increases blood pressure

Adrenomedullin (ADM) circulates in the blood at concentrations comparable to other vasoactive peptides with established roles in cardiovascular regulation. Intravenously administered ADM produces a clear hypotensive effect, whereas intracerebroventricular microinjections result in increases in blood pressure (BP). Recently, we demonstrated that ADM influences neurons of the area postrema (AP), a central nervous system site implicated in cardiovascular control. However, to address directly the physiological significance of the actions of ADM at the AP, an in vivo microinjection study was undertaken. ADM, at two concentrations (1 and 10 microM), in volumes of 50, 100, and 200 nl, was microinjected into the AP or NTS of 21 urethan-anesthetized male Sprague-Dawley rats. Microinjection of 10 microM ADM (100 nl) resulted in significant transient (2-5 min) increases in BP [120 s area under the curve (AUC): 684.3 +/- 268.6 mmHg/s (P < 0.05)], and heart rate (HR) [AUC: 12.5 +/- 4.5 beats/min (P < 0.05)]. The lower concentration of ADM (1 microM) had no effect on either BP (179.1 +/- 143.6 mmHg/s) or HR (0.8 +/- 2.6 beats/min). ADM was also microinjected into the immediately adjacent nucleus of the solitary tract, where it was found to be without effect on either BP or HR. This study demonstrates, for the first time, a physiological role for ADM acting at a specific brain site, the AP, to produce significant cardiovascular responses.

The effect of a home-based, case-managed, multifactorial risk-reduction program on reducing psychological distress in patients with cardiovascular disease

BACKGROUND

This study examined the effects of a nurse-case-managed, multifactorial, risk-reduction program on psychological distress among patients after myocardial infarction (MI).

METHODS

Five hundred eighty-five men and women aged 70 years or younger, who were hospitalized for acute MI in one of five San Francisco Bay Area hospitals, were randomized to receive a nurse-managed, home-based, multifactorial risk-reduction program (n = 293) or usual care (n = 292). The program, which began in the hospital, included a brief screen for five areas of psychological distress with further evaluation if indicated, monitoring during the follow-up phone calls, and referral for mental health treatment if needed. Patients were assessed with single-item scales at baseline, and at 6 and 12 months. Separate analyses were performed for patients with moderate-to-severe levels on the psychological distress domains and for those with low levels.

RESULTS

There was a significant reduction in the psychological distress variables for all patient groups between baseline and 12 months. The program had a significant effect on reducing anxiety in the patient group with low levels of anxiety and reducing anger in the patient group with frequent episodes of anger but, overall, the treatment and control groups showed equal levels of improvement.

CONCLUSION

Among patients post-MI without complications, psychological distress decreases significantly during the 12 months after MI.

Smoking cessation in hospitalized patients. Results of a randomized trial

BACKGROUND

Few research studies have evaluated the effectiveness of smoking interventions in hospitalized patients. This randomized controlled trial compared the efficacy of 2 smoking cessation programs in patients hospitalized in 4 community hospitals in a large health maintenance organization within the San Francisco Bay Area in California.

METHODS

Patients were randomly assigned to usual care (n = 990), nurse-mediated, behaviorally oriented inpatient counseling focused on relapse prevention with 1 postdischarge telephone contact (minimal intervention, n = 473), or the same inpatient counseling with 4 postdischarge telephone contacts (intensive intervention, n = 561). The main outcome measure, smoking cessation rate, was corroborated by plasma cotinine determination or family confirmation, 1 year after enrollment.

RESULTS

At 1 year smoking cessation rates were 27%, 22%, and 20% for intensive intervention, minimal intervention, and usual care groups, respectively (P = .009 for intensive vs usual care). Subgroup analyses by diagnosis revealed that the odds of cessation among patients with cardiovascular disease or other internal medical conditions were greater among those receiving the intensive intervention than among their counterparts receiving usual care (odds ratios, 1.6 and 2.0, respectively).

CONCLUSIONS

A multicomponent smoking cessation program consisting of physician advice; in-hospital, nurse-mediated counseling; and multiple postdischarge telephone contacts was effective in increasing smoking cessation rates among hospitalized smokers. Hospital-wide smoking cessation programs could substantially increase the effectiveness of hospital smoking bans.

Randomised double blind controlled study of recurrence of gastric ulcer after treatment for eradication of Helicobacter pylori infection

OBJECTIVE

To determine whether eradication of Helicobacter pylori infection reduces recurrence of benign gastric ulceration.

DESIGN

Randomised, double blind, controlled study. Patients were randomised in a 1:2 ratio to either omeprazole 40 mg once daily for eight weeks or the same treatment plus amoxycillin 750 mg twice daily for weeks 7 and 8. A 12 month untreated follow up ensued.

SETTING

Teaching and district general hospitals between 1991 and 1994.

SUBJECTS

107 patients with benign gastric ulcer associated with H pylori.

MAIN OUTCOME MEASURES

Endoscopically confirmed relapse with gastric ulcer (analysed with life table methods), H pylori eradication, and healing of gastric ulcers (Mantel-Haenszel test).

RESULTS

172 patients were enrolled. Malignancy was diagnosed in 19; 24 were not infected with H pylori; four withdrew because of adverse events; and 18 failed to attend for start of treatment, leaving 107 patients eligible for analysis (35 omeprazole alone; 72 omeprazole plus amoxycillin). In the omeprazole/amoxycillin group 93% (67/72; 95% confidence interval 84% to 98%) of gastric ulcers healed and 83% (29/35; 66% to 94%) in the omeprazole group (P = 0.103). Eradication of H pylori was 58% (42/72; 46% to 70%) and 6% (2/35; 1% to 19%) (P < 0.001) and relapse after treatment was 22% (16/72) and 49% (17/35) (life table analysis, P < 0.001), in the two groups, respectively. The recurrence rates were 7% (3/44) after successful H pylori eradication and 48% (30/63) in those who continued to be infected (P < 0.001).

CONCLUSIONS

Eradication of H pylori reduces relapse with gastric ulcer over one year. Eradication rates achieved with this regimen, however, are too low for it to be recommended for routine use.

A shift in the requirement for CD4+ T cells in the generation of AKR/Gross MuLV-specific CTL in AKR.H-2b:Fv-1b mice occurs prior to the onset of age-dependent CTL nonresponsiveness

In the current study, the elimination of CD4+ T cells from B6 mice, by treatment with anti-CD4 monoclonal antibody, had little effect on their ability to mount an AKR/Gross (MuLV)-specific CTL response. In contrast, for AKR.H-2b:Fv-1b mice, there was a shift as the mice aged from 5 to 7 weeks to a requirement for CD4+ T cells for AKR/Gross MuLV-specific CTL generation. When CD4+ T-cell-depleted AKR.H-2b:Fv-1b responder mice were immunized at 5 weeks of age they were able to elicit a strong anti-AKR/Gross MuLV CTL response. However, if the CD4+ T-cell depletion was done at 6 weeks and then the mice were primed in vivo, their antiviral CTL responsiveness was markedly decreased. Following CD4+ T-cell depletion at 7 weeks the mice were totally incapable of generating anti-AKR/Gross MuLV-specific CTL. AKR/Gross MuLV-specific CTL isolated from AKR.H-2b:Fv-1b mice recognized the class I-restricted immunodominant epitope (KSPWFTTL) and three subdominant epitopes, previously identified as CTL epitopes for B6 mice. Analysis of IL-2, IFN-gamma, IL-4, and IL-10 lymphokine profiles in supernates harvested from MLTC wells, and the results of supernate transfer experiments, suggested that the age-dependent shift to CD4+ T-cell dependence in AKR.H-2b:Fv-1b mice does not correlate with an obvious change in the in vitro lymphokine profiles. Experiments in which exogenous IL-2 was used to supplement in vitro cultures containing CD4+ T-cell-depleted 7-week responder mice suggested that the CD4+ T-cell requirement was at the in vivo priming stage of antiviral CTL generation. These data suggested a fundamental change in virus-specific CTL which correlates with slight aging in the AKR.H-2b:Fv-1b mouse strain. To our knowledge, this is the first report of a shift in the requirement for CD4+ T lymphocytes for the generation of virus-specific CTL over such a short period of time. Moreover, it is of interest that this shift in CD4+ T-cell-dependence by antiviral CTL occurs just prior to the onset of CTL nonresponsiveness in the AKR.H-2b:Fv-1b mouse strain.

Changing patterns of self-poisoning in a UK health district

Details of admissions to a dedicated district poisons treatment unit in South Glamorgan were analysed to assess changes in self-poisoning patterns between 1987-1988 and 1992-1993. Self-poisoning rates increased in both men and women, with male rates showing a relatively larger increase, resulting in a fall in female to male ratio for person-based rates from 1.33:1 to 1.13:1. The highest age-specific rates in both period were found in 15-19-year-old females. Paracetamol was the most commonly ingested poison in 1992-1993, with 43.4% of episodes involving its use, compared with 31.3% of episodes in 1987-88. Antidepressant involvement in self-poisoning also increased from 11.3% of episodes in 1987-1988 to 17.6% of episodes in 1992-1993. Repetition of self-poisoning was relatively common, with 18% of admissions per year in 1992-1993 representing repeats. Although hospital admission increased in this health district over the study periods, this was not reflected in an increase in in-patient all-cause mortality, which was only 0.5% in 1987-1988 and 0.1% in 1992-1993.

A nurse-managed smoking cessation program for hospitalized smokers

OBJECTIVES

This study evaluated a nurse-managed smoking cessation program for smokers hospitalized for a variety of conditions.

METHODS

Hospitalized patients who smoked prior to hospitalization and who were motivated to quit (n = 660) were randomized to intervention or usual-care groups and followed for the next year. The intervention included a meeting with the nurse-case manager; the use of a videotape, workbook, relaxation audiotape, and nicotine replacement therapy; and nurse-initiated phone contacts after discharge.

RESULTS

The 12-month confirmed cessation rates were 21% and 31% for, respectively, the usual-care and intervention groups (odds ratio = 1.7; 95% confidence interval = 1.1, 2.3).

CONCLUSIONS

A nurse-managed smoking cessation intervention can significantly increase cessation rates for hospitalized patients.

Therapeutic cup insemination with cryopreserved donor sperm: prognostic value of cervical mucus score at insemination and the number of motile sperm in mucus at 24 hours

OBJECTIVE

To examine the prognostic value of cervical mucus score at insemination and the number of motile sperm in mucus 24 hours after therapeutic cup insemination with cryopreserved donor sperm.

DESIGN

Retrospective analysis.

SETTING

Academic tertiary medical center.

PATIENTS

One hundred thirty-eight women with confirmed bilateral tubal patency who received therapeutic cup inseminations with cryopreserved donor sperm between 1986 and 1993.

INTERVENTIONS

All insemination cycles were monitored with serial daily urinary LH determinations with a single (n = 312) insemination or two inseminations (n = 212) performed on and/or 1 day after the day of LH surge detection. A single examiner assigned cervical mucus scores in all insemination cycles and recorded the number of motile sperm in mucus 24 hours after the first insemination in dual insemination cycles.

MAIN OUTCOME MEASURE

Pregnancy rate during various cervical mucus and motile sperm scores.

RESULTS

Ninety-one women conceived (66%) and seven of these achieved two pregnancies. The overall pregnancy rate per insemination cycle was 18.7%. Age and day of insemination were the only variables identified as having significant influence on cycle outcome. Pregnancy occurred with decreasing frequency as patient age increased and was nearly twice as likely after insemination on the day after the urinary LH surge as on the day of surge detection.

CONCLUSIONS

Insemination the day after the urinary LH surge is superior to the day of surge detection. Cervical mucus score and the number of motile sperm in mucus 24 hours after therapeutic cup insemination with cryopreserved donor sperm do not correlate with cycle outcome.

Amplification of the thapsigargin-evoked increase in the cytosolic free Ca2+ concentration by acetylcholine in acutely isolated mouse submandibular acinar cells

The intracellular Ca2+ concentration was measured in single, acutely isolated, mouse submandibular acinar cells loaded with fura-2 AM. All experiments were performed in the absence of extracellular Ca2+ in order to eliminate Ca2+ influx. The microsomal ATPase inhibitor, thapsigargin, was used to release Ca2+ from intracellular stores and simultaneously prevent re-uptake into the stores. Sequential application of thapsigargin (2 microM) and the Ca2+ ionophore ionomycin (500 nM) indicated that thapsigargin was able to mobilize practically all intracellular Ca2+. Furthermore, in comparison with results obtained following inhibition of the plasma membrane Ca(2+)-ATPase by La3+ (2 mM), it may be shown that slowly unloading the intracellular Ca2+ stores using thapsigargin does not normally cause a massive, cytotoxic, increase in the cytosolic Ca2+ concentration, because Ca2+ is rapidly extruded from the cell across the plasma membrane. Application of a submaximal dose of acetylcholine (500 nM) during the rising phase of the response to thapsigargin caused a 3-4-fold increase in the amplitude of the rise in the cytosolic Ca2+ concentration without any significant alteration of the time course of the response. As thapsigargin alone is capable of mobilizing all releasable Ca2+, this increase in amplitude is most likely the result of inhibition of the Ca2+ extrusion process by acetylcholine.

Cloning and expression in yeast Pichia pastoris of a biologically active form of Cyn d 1, the major allergen of Bermuda grass pollen

BACKGROUND

Pollen of grasses, such as Bermuda grass (Cynodon dactylon), represent a major cause of type I allergy.

OBJECTIVE

In this report we attempted to clone and express a biologically active form of recombinant Cyn d 1, the major allergen of Bermuda grass pollen, in the yeast Pichia pastoris.

METHODS

Clones encoding Cyn d 1 were isolated by screening a Bermuda grass pollen complementary DNA library with specific monoclonal antibodies and by polymerase chain reaction amplification. Recombinant Cyn d 1 was expressed in Escherichia coli and yeast. The expressed proteins were analyzed by Western blotting to assess binding to Cyn d 1-specific monoclonal antibodies and IgE from sera of patients allergic to Bermuda grass pollen.

RESULTS

Two isoforms of Cyn d 1 were cloned. Recombinant Cyn d 1 expressed in bacteria bound two monoclonal antibodies raised against Cyn d 1 but was not recognized by IgE from sera of patients allergic to Bermuda grass pollen. Cyn d 1 expressed in yeast bound both the monoclonal antibodies and human IgE.

CONCLUSION

An IgE-reactive Cyn d 1 was expressed in yeast but not in bacteria, suggesting that posttranslational modifications (e.g., glycosylation), which occur in eukaryotic cells such as yeast, are necessary for the production of a biologically active allergen.

Occupationally related angiosarcoma of the liver in the United Kingdom 1972-1994

BACKGROUND

Angiosarcoma of the liver (ASL) has been described in vinyl chloride workers worldwide.

AIM

To describe the UK experience of occupationally related ASL.

PATIENTS

Twenty patients who died from ASL after exposure to vinyl chloride.

METHODS

The case records and pathological findings of these 20 patients were reviewed.

RESULTS

Twenty men in the United Kingdom aged 37 to 71 years have developed ASL in association with occupational exposure to vinyl chloride monomer VCM in two factories. All had been exposed to VCM for three to 29 years, the tumour developing nine to 35 years after first exposure. Presenting clinical features included abdominal pain, malaise, jaundice, ascites, and massive hepatomegaly. In most cases the disease progressed rapidly, death occurring within a few weeks from hepatic coma. In 17 cases there was no spread outside the liver. In four cases there had been haemorrhage from oesophageal varices due to non-cirrhotic portal fibrosis diagnosed six to 18 years previously. At necropsy the livers of these men showed considerable, often massive, replacement by tumour, apparently multifocal, with necrosis and haemorrhage.

CONCLUSIONS

In view of the long latency between exposure and development of the tumour the full extent of ASL occurrence may not be known until 35 years after the introduction of the Code of Practice in 1975.

Intermodal agreement of follow-up telephone functional assessment using the Functional Independence Measure in patients with stroke

OBJECTIVE

To examine the intermodal agreement of Functional Independence Measure (FIM) ratings when obtained by two commonly used approaches: telephone interview and in-person assessment of functional performance.

DESIGN

A random sample of 40 persons with hemiparesis was tested by two registered nurses trained in FIM definitions and telephone interview techniques. The two assessments occurred within 5 days of each other. The raters were blind to previous assessments. The administration of assessments was alternated to minimize bias and order effects.

SETTING

All subjects were assessed at home, between 3 and 10 months after discharge from rehabilitation.

PATIENTS

The criteria for inclusion were: (1) diagnosis of cerebral vascular accident (CVA); (2) completion of a minimum of 2 weeks in an acute rehabilitation program; (3) currently living at home; (4) living within a 30-mile radius of the hospital; and (5) cognitive and verbal skills adequate to complete a telephone interview. From a population of 103 patients, 40 subjects were randomly selected, 18 women and 22 men ranging in age from 37 to 90 years.

MAIN OUTCOME MEASURES

The intermodal agreement between FIM ratings obtained by telephone interview and in-person assessment was examined using the intraclass correlation (ICC). FIM item scores were analyzed for agreement using the Kappa coefficient. The stability of the responses was determined by computing the coefficient of variation and plotting the data to visually examine the relationship between the two methods of administration.

RESULTS

Data analysis revealed that there was no statistically significant difference (p > .05) between the two methods of administration for total FIM score. The total FIM ICC was .97. ICC values for FIM subscales ranged from .85 to .98, except for social cognition. Kappa scores for noncognitive items ranged from .49 (bowel movement) to .93 (grooming). The coefficient of variation computed to examine cognitive and communication items with reduced variability indicated good stability across all items.

CONCLUSION

The results indicated good intermodal agreement for follow-up telephone assessment using the Functional Independence Measure. The findings were limited to persons with effective communication skills.

Paraventricular nucleus efferents influence area postrema neurons

Extracellular single-unit recordings were obtained from area postrema neurons (AP), and peristimulus histograms were used to determine the effects of paraventricular nucleus (PVN) stimulation on these cells from anesthetized Sprague-Dawley rats. Of 91 AP cells tested, 30.8% responded to PVN stimulation with a short-latency (28.2 +/- 3.3 ms, mean +/- SE), short-duration (49.3 +/- 8.0 ms) excitation, whereas 8.6% were inhibited. In animals that had stimulation sites outside of PVN (non-PVN), only 4 of the 72 AP cells tested (5.6%) were influenced by stimulation. These excitatory effects of PVN stimulation on AP neurons were unaffected by V1-receptor blockade. Of 93 nucleus of the solitary tract (NTS) cells tested, 38.9% responded to PVN stimulation with a short-latency (18.5 +/- 2.4 ms), short-duration (48.8 +/- 9.6 ms) excitation and 22.2% with short-latency (20.75 +/- 4.1 ms), long-duration (204.4 +/- 44.9 ms) inhibitions. In contrast, non-PVN stimulation sites influenced only 19% of NTS neurons tested, all of which were excited. These data demonstrate that activation of PVN neurons elicits excitatory effects on the majority of AP neurons influenced. They further emphasize the potential significance of descending hypothalamic inputs in controlling neuronal activity in this circumventricular organ.

Recombinant expression and epitope mapping of grass pollen allergens

We have studied the expression of recombinant forms of Group 1 allergens from rye-grass and Bermuda grass pollens. Recombinant Lol p 1 expressed in bacteria bound serum IgE from allergic patients. Based on analysis of fragments of the Lol p 1 cDNA clone, the major IgE-reactive epitope has been mapped to the C-terminus. However, although SDS-denatured natural Cyn d 1 (from Bermuda grass) bound IgE, the full or partial recombinant proteins expressed in bacteria did not bind IgE. We have since expressed Cyn d 1 in the yeast Pichia pastoris and restored IgE binding. cDNA clones encoding two isoforms of Lol p 5, Lol p 5A and Lol p 5B, have been expressed in bacteria and resulting polypeptides show IgE-binding. Random fragments of these clones have been generated and when expressed as partial recombinant proteins in bacteria, allowed us to identify the major IgE-binding epitopes. The allergenic epitopes were localised towards the C-terminal half of the molecule. Although both isoforms shared similar IgE-reactive epitopes, Lol p 5B did not recognise the Lol p 5A-specific monoclonal antibody A7. At sequence level, there appear to be several amino acid differences between the antigenic epitopes of these two isoallergens. These results aid in the design of diagnostics and in grass pollen immunotherapy.

New fears in gynecologic cancer

BACKGROUND

A review of the psychosocial oncology literature indicates the paucity of psychological services available in early detection programs, yet there is an increasing awareness of the need to attend to the psychosocial distress of women whose mothers have had ovarian cancer. The explosion of information transmitted to the public through the news media about ovarian cancer, early detection, and genetic susceptibility should heighten the scientific community's sensitivity to the apprehensions of women who are first-degree relatives of women with ovarian cancer.

METHOD

The emotional fragility of participants in the early detection ovarian cancer screening program at Yale University is addressed through an initial counseling session. An open-ended, unstructured interview was designed to enable participants to express their concerns about ovarian cancer. This experience is being evaluated.

RESULTS

Through psychosocial assessment and evaluation, the authors observed that life cycle events, unresolved episodic grief, cognitive adaptation to loss, and interpersonal relationships contribute to the importance of total care and medical responsibility for the gynecologic cancer patient. Psychosocial counseling has been an integral component of the Yale Early Detection Program since its inception. Preliminary results suggest the necessity of continued counseling intervention to address women's increased anxieties about gynecologic cancers.

CONCLUSION

Special attention must be paid to the psychological needs of vulnerable subjects in disease-screening programs. Medical providers of early detection screening should rigorously explore the psychosocial aspects of early detection and provide appropriate intervention to meet women's needs.

Endoscopic intubation of oesophago-gastric malignancy

OBJECTIVE

To determine what percentage of inoperable oesophageal and oesophagogastric malignancies could be successfully intubated for palliation, and to compare Atkinson and Celestin tubes.

DESIGN

A consecutive series of 210 patients who had been referred for palliation underwent endoscopy and intubation with the Nottingham introducer.

PATIENTS

One hundred and nineteen men and 91 women aged 31-91 (mean age 71) years with inoperable malignant obstruction of the oesophagus or gastro-oesophageal junction were studied. One hundred and five tumours were in the lower third of the oesophagus, 78 in the middle third, 25 in the upper third and seven in the gastric fundus. Four tracheo-oesophageal fistulae resulting from bronchial carcinomas were also successfully intubated. MAJOR OUTCOME MEASURE: Eighty-nine per cent of gastro-oesophageal malignancies were successfully intubated using 120 Atkinson and 67 Celestin tubes.

RESULTS

Eleven patients (5.2%) suffered oesophageal perforations during intubation, of whom six died. Nine of the perforations occurred in the first 100 patients treated but only two (2.3%) in the subsequent 87. Seven patients (3.7%) developed aspiration pneumonia, of whom five died. The mean survival time after intubation was 4.5 months (range 0.5-20 months), and 74% of patients required no further procedure. During follow-up, five (4.2%) Atkinson tubes displaced upwards, compared with 12 (17.9%) Celestin tubes (P < 0.01). Eighteen (9.6%) patients had recurrent dysphagia as a result of bolus obstruction and 11 (5.9%) had tumour overgrowth of the tube.

CONCLUSION

Palliative intubation of malignant dysphagia is possible in approximately 90% of patients. The mortality associated with the procedure is low (5%) and effective relief of symptoms is achieved, with 74% of patients requiring no further treatment.

Subfornical organ stimulation elicits drinking

The subfornical organ is a specialized central nervous system structure known to be involved in the control of drinking. We report here that electrical activation of subfornical organ neurons (100 microA, 10 Hz, 1 ms pulse width, for 5 min.) induced drinking in 67% (six of nine) of animals. This effect was site-specific as none of the animals with electrode placements (n = 7) dorsal or rostral to the subfornical organ drank in response to electrical stimulation. In contrast, activity levels were increased significantly during stimulation in both the subfornical and nonsubfornical organ stimulated groups. These results suggest that electrical stimulation of the subfornical organ can elicit site-specific drinking behaviour and provide further support for the involvement of the subfornical organ in the control of drinking behaviour.

Diagnosis of infection by frozen section during revision arthroplasty

We assessed the efficacy of intraoperative frozen-section histology in detecting infection in failed arthroplasties in 106 hips and knees. We found inflammatory changes consistent with infection (an average of one or more neutrophil polymorphs or plasma cells per high-power field in several samples) in 18 cases; there was a significant growth on bacterial culture in 20 cases. Compared with the bacterial cultures, the frozen sections provided two false-negative results and three false-positive results (sensitivity, 90%; specificity, 96%; and accuracy, 95%). The positive predictive value was 88%, the negative value, 98%. These results support the inclusion of intra-operative frozen-section histology in any protocol for revision arthroplasty for loose components.