The dopamine D3 receptor and schizophrenia: pharmacological, anatomical and genetic approaches

Antipsychotic drug therapy mainly rests on the use of antagonists of dopamine D2-like (D2, D3 and D4) receptors, for which all clinically active compounds have high affinity. The D3 receptor has a restricted expression in brain limbic areas, associated with cognitive functions and motivated behavior. D3 selective agonists and antagonists reveal an inhibitory role on motor behaviors for the D3 receptor, opposite to that of the D2 receptor. An opposing role for D2 and D3 receptors is also suggested by the contrasted effects of D2/D3 antagonists on neurotensin expression in discrete subdivisions of nucleus accumbens, where D2 and D3 receptors are selectively expressed. Tolerance to the motor but not to the therapeutic effects of neuroleptics is observed after repeated administration, which upregulates the D2, but not the D3 receptor in animals. In genetic association studies, an excess of homozygosity for both alleles of the BalI polymorphism at the D3 receptor gene was found in schizophrenic patients, suggesting that this gene may have subtle influence on the liability to develop schizophrenia. These results suggest the D3 receptor as an important target for antipsychotic drug action, and D3 receptor selective antagonists as promising therapeutic agents.

The human cardiac mast cell: localization, isolation, phenotype, and functional characterization

We have isolated and characterized the human cardiac mast cell (CMC) and compared this novel mast cell (MC type with MC obtained from uterus, skin, and lung. Heart tissue was obtained from 14 patients with cardiomyopathy (CMP, heart transplantation). CMC were isolated by enzymatic digestion using collagenase, pronase-E, hyaluronidase, and DNAse. Substantial amounts of CMC (0.5% to 1.5% of isolated cells) were found in the atrial appendages but not in ventricular digests or other sites of the heart (< 0.1%). In situ staining of atrial tissue revealed the presence of CMC in the myocardium (2.16 +/- 0.7 MC/mm2), endocardium (2.24 +/- 0.9 MC/mm2), and epicardium. As assessed by combined toluidine blue/immunofluorescence staining with monoclonal antibodies (MoAbs), isolated CMC expressed surface IgE, the receptor for stem cell factor (c-kit receptor/CD117), the p24 antigen (CD9), the Pgp-1 homing receptor (CD44), the pan leukocyte antigen (CD45), and the ICAM-1 antigen (CD54). CMC were not recognized by MoAbs to lymphocyte function associated antigen 2 (LFA-2; CD2), T-cell receptor (TcR; CD3), T4 antigen (CD4), LFA-1 alpha-chain (CD11a), C3biR alpha-chain (CD11b), CR4 alpha-chain (CD11c), LPS-R related Ag (CD14), 3-FAL/x-hapten (CD15), Fc gamma RIII (CD16), lactosylceramid (CDw17), the B-cell antigen CD19, or CR1 (CD35). In situ expression of leukocyte antigens on CMC was demonstrable by indirect immunoperoxidase staining technique and double-labeling immunohistochemistry. Almost all CMC (90%) reacted with MoAbs against tryptase and chymase and thus were MCTC. Cardiac mast cells were also stained by the heparin-binding dye Berberine sulfate and expressed measurable amounts of histamine (4.6 +/- 1.4 pg per cell). Cross linking of either IgE receptor or SCF receptor (c-kit) on CMC resulted in histamine secretion (non-specific release: < 6% of total histamine, alpha IgE induced: 12% to 52%; SCF-induced release: 9% to 18%), whereas neither substance P (a skin MC agonist) nor the basophil agonist FMLP showed an effect on CMC. Together, the CMC is an MCTC primarily located in the appendage of the atrium. This novel type of MC exhibits surface membrane antigen and functional properties similar to those of lung and uterus MC.

Typing of Clostridium perfringens by in vitro amplification of toxin genes

The strains of Clostridium perfringens are classified according to major toxins produced. Classically, this determination involves the seroneutralization of their lethal effect in mice. However, this method requires specific antisera and a large number of mice. In this work, a new typing method was developed based on the amplification of toxin genes by polymerase chain reaction (PCR). By combination of several pairs of primers, the toxinotype of a Cl. perfringens strain was determined by looking at the pattern of bands on an agarose gel electrophoresis. This mixture contained primers amplifying simultaneously a part of alpha-toxin, beta-toxin, epsilon-toxin and enterotoxin genes. In order to distinguish between toxinotype A and E, the l-toxin gene fragment must be amplified in a separate PCR reaction. Moreover, with the primers combination, in most cases, a PCR product corresponding to the alpha-toxin gene was obtained from direct enrichments of animal intestinal contents.

Experience of a single team of operators in 891 diagnostic funipunctures

OBJECTIVE

To assess the efficacy and safety of diagnostic funipuncture.

METHODS

Between October 1985 and November 1993, fetal circulation was accessed 891 times in 828 pregnancies. The technique was similar to that described in earlier studies. We did not make more than two attempts at the procedure in any session. Each procedure was recorded prospectively in a computerized data base. Data included information about indications, laboratory indices, gestational age, number of successful and failed punctures, duration of fetal bradycardia, duration of bleeding, ultrasonographic findings, follow-up of pregnancies, and perinatal outcome.

RESULTS

The most frequent indication was rapid karyotyping (48.9%), followed by risk of congenital infection (38.6%). The success rate of the method was high (98.6%). Most samples (97%) were pure fetal blood, undiluted by amniotic fluid. Transient bleeding was observed from the cord puncture site in 9.8% of the procedures. Sixty-three percent of prolonged bradycardia occurred in growth-retarded or congenitally malformed fetuses. Seven fetal and neonatal deaths (five pregnancies) occurred within 1 week after the funipuncture; the funipuncture indication was rapid karyotyping in four of these cases.

CONCLUSION

Funipuncture performed by operators trained in ultrasonic needle guidance is a safe and reliable procedure.

Drooping upper eyelids and polycystic kidney disease

Over the last 26 yr, 33 cases and/or families of patients with autosomal dominant polycystic kidney disease (ADPKD) and a particular appearance of the eyes have been observed. ADPKD was unremarkable and in most cases had led to the usual slow development of end-stage renal failure. The facial feature concerned the upper eyelid, which drooped obliquely over the eyeball with a fold hiding the upper segment of the iris (blepharochalasis). The aspect was so typical that the diagnosis of ADPKD was suggested on first contact with new renal patients. All affected patients were white, of various origins, including French, Polish, Scandinavian, Italian, and Spanish. In retrospect, drooping eyelids had been present in the parents and/or grandparents who had died of renal failure, with or without an established diagnosis of ADPKD. In order to disclose the cosegregation of blepharochalasis with ADPKD, the screening of its prevalence in a well-circumscribed region with a catchment population of 410,000 was undertaken. The facial feature was found in 24 (32%) of 75 ADPKD families. Family transmission was confirmed in those kindreds, because at least two members suffered from ADPKD. Cosegregation was sought by analyzing family group photographs taken over several generations, the oldest member of which was born in 1973. All members with blepharochalasis had died of renal failure or are presently being followed up for ADPKD. A bibliographic search showed that the association of ocular and/or eyelid deformities and various inborn renal diseases is far from rare, suggesting a simultaneous event in the embryonic timetable.(ABSTRACT TRUNCATED AT 250 WORDS)

Thoracoabdominal aneurysm repair: spinal cord protection using profound hypothermia and circulatory arrest

Between January 1991 and February 1993, 14 patients (11 male, 3 female) between 21 and 79 years of age (median 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, and in three patients coronary artery bypass grafting had previously been performed. All patients were operated on a via a posterolateral thoracotomy using cardiopulmonary bypass with continuous blood cardioplegia and hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, flat-EEG). All patent lower intercostal and lumbar arteries (T3 to L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0%; after replacement of the thoracoabdominal aorta, mortality was 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurological deficit or renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic aorta and 18 days for patients after replacement of the thoracoabdominal aorta. Our results suggest that use of elective hypothermia and circulatory arrest for spinal cord protection is highly effective. We, therefore, recommend this method for complex reconstructions of the thoracoabdominal aorta.

Evaluation in patients with Alport syndrome of knowledge of the disease and attitudes toward prenatal diagnosis

Cloning of the COL4A5 gene has now made possible prenatal testing for Alport syndrome with X-linked dominant inheritance. We interviewed 27 females and 24 males with Alport syndrome to evaluate their knowledge of the disease and its transmission, and their attitudes to prenatal testing. Twenty-two males and 8 females were on renal replacement therapy. In all cases transmission was compatible with X-linked disease. Only 59% of the interviewees (74% of women, 42% of men) knew that gender was the major determinant in progression of the disease. Knowledge of the mode of inheritance was adequate in only 25%, in both sexes. Seventy percent of the participants (78% of women, 63% of men) would use prenatal testing. Of the women in favor of prenatal diagnosis, 67% and 39% would terminate pregnancy in the case of an affected male or female fetus, respectively. Of the men in favor of prenatal diagnosis, 53% would consider termination of an affected fetus. In summary, a majority would use prenatal testing, but only one or two thirds of them wished to use selective abortion. As in other inherited disorders, there is a discrepancy between the demand for prenatal diagnosis and the decision to terminate pregnancy. Most of the participants who would terminate a pregnancy had, however, little knowledge of the clinical and genetic aspects of Alport syndrome on which to base such a decision. An important aspect of genetic counselling is to assist consultants in reaching a decision regarding future reproductive behaviour which is appropriate to their situation. This study underlines the need to improve education and counselling to assure appropriate use of prenatal testing.

Epidemiology of primary glomerular diseases in a French region. Variations according to period and age

Between January 1, 1976 and December 31, 1990, histological diagnosis of primary glomerular diseases (PGD) was made in 480 patients born and living at the time of diagnosis in a region of France, comprising 410,664 inhabitants, of whom 390,574 were aged from 10 to 80 years. The prevalence of PGD during a 70 year exposure to risk (10 to 80 years of age) was evaluated to 5.7 in 1000 (7.6 in 1000 males and 3.8 in 1000 females). The most common PGD was IgA nephropathy with a prevalence of 1.9 in 1000 (3.3 in 1000 males, 1 in 1000 females). The annual incidence of the disease was evaluated separately for three consecutive five-year periods: period A (1976-80), period B (1981-85), and period C (1986-90). Within each of these three periods the number of patients with PGD was 179, 170 and 131, respectively, and annual incidence was 9.3, 8.8 and 6.7 in 100,000. The incidence of IgA nephropathy remained the same throughout the three periods: 2.6, 3.1 and 2.5 in 100,000. The incidence of membranoproliferative glomerulonephritis decreased from 1981 onward (0.9, 0.5 and 0.15 in 100,000), while that of membranous nephropathy increased slightly (1.2, 1.6 and 1.7 in 100,000). Acute streptococcal glomerulonephritis virtually disappeared during periods B and C. Lipoid nephrosis was less frequent in period C and idiopathic proliferative glomerulonephritis with crescents slightly increased (0.3, 0.4 and 0.6 in 100,000). There was no significant difference between the three periods regarding the incidence of other PGD.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ambulatory blood pressure determination]

Recent studies have confirmed that the mean blood pressure levels recorded during ambulatory monitoring are lower than the levels measured by the standard cuff method, possibly due to the "white coat" effect which involves as many as 25 to 30% of the total hypertensive population. In addition, ambulatory blood pressure monitoring is particularly useful to evaluate the day/night cycle. Loss of the normal decrease in blood pressure at night occurs in certain types of secondary hypertension and can be revealed by ambulatory monitoring. The importance of the morning peak in determining prognosis in patients suspected of having hypertension is illustrated by the large number of cardiovascular events which occur during this period. There is also a close correlation between the mean 24-hour blood pressure and cardiovascular prognosis. Studies have demonstrated that the loss of the circadian rhythm or the mean 24-hour blood pressure are significantly correlated with type I diabetes mellitus, the risk of cerebral vascular events and left ventricle hypertrophy. Ambulatory monitoring is also a particularly useful method in clinical trials. Reproducible results can be obtained in the same individual and there is no placebo effect, making it possible to reduce the number of participants and thus raise the statistical power of the test. Ambulatory monitoring can also modify management decisions as found in a recent survey conducted in the United States demonstrating the impact on the treatment of hypertension. For 30 to 40% of the hypertensive patients, therapeutic management was different after ambulatory monitoring than after conventional cuff measurement. Standardization will be the next step in the widespread use of ambulatory blood pressure monitoring.

Dietary habits, a non-negligible source of 2-thiothiazolidine-4-carboxylic acid and possible overestimation of carbon disulfide exposure

2-Thiothiazolidine-4-carboxylic acid (TTCA) is the accepted urinary indicator of occupational exposure to carbon disulfide. This compound was detected in blank urine of individuals unexposed to carbon disulfide during an experimental validation of a new method of determination. Diet was suspected to be the source of TTCA, and particularly the consumption of brassica vegetables. This assumption was confirmed by collection and analysis of urine samples after ingestion of crude cabbage. TTCA was detected at concentrations higher than 2 mg/l in urine, and 3 mg/kg in crude cabbage. The identity of TTCA was confirmed after extraction and separation by capillary electrophoresis, supercritical fluid chromatography, and mass spectrometry. The results show that the diet should be considered as a nonnegligible source of the overestimation of carbon disulfide exposure.

The atpB and rbcL promoters in plastid DNAs of a wide dicot range

The plastid atpB-rbcL intergene has been analyzed within a wide range of plants covering the major dicot lineages. New sequences from 13 plant species were determined and aligned with three already-known sequences. The promoters of the rbcL and the atpB genes were localized and analyzed according to published observations in spinach and tobacco. The evolutionary conservation of two atpB promoters, separated by 113-262 nucleotides, is strong support that both are functionally active, and it also allows a discrimination between the previously reported atpB transcripts. Moreover, the radically distinct sequences of the two atpB promoters suggest that they interact with two distinct initiation complexes. The alignment also confirms the much higher conservation of the leader sequence in the rbcL mRNA than in the atpB mRNA among dicots, presuming a function at the posttranscriptional level.

The stimulant effect of modafinil on wakefulness is not associated with an increase in anxiety in mice. A comparison with dexamphetamine

Modafinil is a new drug used in the treatment of narcolepsy. Its administration in mice induced a dose-dependent increase in locomotor activity. The effects of modafinil were compared with those of dexamphetamine on three tests that assessed the anxiety level (drugs were used at doses which induced a roughly similar stimulation of locomotor activity). Dexamphetamine increased the latency of exploration of a white compartment, increased thigmotaxis in an open-field and decreased the time spent in the open arms of an elevated plus-maze. None of these responses was significantly modified by modafinil. We conclude that modafinil does not share the anxiogenic effects of dexamphetamine.

The effects of dobutamine therapy in critically ill patients measured by transoesophageal echocardiography and intracardiac monitoring

Fourteen patients with severe hypotension and adult respiratory distress syndrome after trauma (n = 7), general surgery (n = 6) or burns (n = 1) were studied. After volume loading with 6 ml.kg-1 hydroxyethyl starch over 30 min (time I), dobutamine was infused intravenously at 5 micrograms.kg-1.min-1 (time II) and 10 micrograms.kg-1.min-1 (time III). A 5 MHz transoesophageal echocardiographic probe was used to image a standard transgastric short axis view of the left ventricle. Haemodynamic data were obtained from thermodilution studies using pulmonary flotation catheterisation. Echocardiographic measurements (off-line from videotape) and qualitative visual assessment of left ventricular function (visual assessment, on-line) were performed. All measurements were made after fluid replacement, and during infusion of the two dobutamine doses. An improvement in mean systemic arterial blood pressure and mean stroke volume occurred from time I to the end of dobutamine infusion (p < 0.05). All patients, after volume infusion, were normovolaemic according to transoesophageal echocardiography and there was a good correlation between end-diastolic area and stroke volume (r = 0.73). During dobutamine infusion, echocardiographic measurements showed no significant dose-related increase in mean (SD) percentage left ventricular short axis area change from baseline after hydroxyethyl starch (time I: 60 (2); time II: 63 (2); time III: 64 (2)). However, a significant increase in short axis area change was seen in nine of the 14 patients (67%). Analysis of the end-diastolic area/short axis area change relationship revealed a heterogeneous response to dobutamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Thigmotaxis as an index of anxiety in mice. Influence of dopaminergic transmissions

When mice are introduced into an open-field, they are inclined to explore mainly the peripheral zone of this open-field. This tendency to remain close the walls, called thigmotaxis, decreases gradually during the first minutes of exploration. We have considered the degree of thigmotaxis during this period of decrease as an index of anxiety in mice. This hypothesis has been validated with several reference anxiogenic drugs (dexamphetamine, pentylenetetrazole, yohimbine, idazoxan) which increased thigmotaxis; and with anxiolytic drugs (buspirone, phenobarbital), which reduced it. On this test the selective or non-selective indirect dopamine agonists GBR 12783, dexamphetamine and cocaine induced an increase of thigmotaxis. Finally, the simultaneous involvement of D1 and D2 dopamine receptors has been evidenced in the anxiogenic-like effect associated with an increase of dopaminergic transmissions.

Aprotinin does not decrease early graft patency after coronary artery bypass grafting despite reducing postoperative bleeding and use of donated blood

Forty-five male patients with planned coronary artery bypass operation were randomized in a double blind fashion to receive either 6 million kallikrein inactivator units of aprotinin (high-dose group), 2 million kallikrein inactivator units of aprotinin (low-dose group), or placebo (control group). Postoperative bleeding was significantly decreased in both aprotinin groups in comparison to that in the control group (590 ml [290 to 1800 ml] high-dose group and 650 ml [280 to 1900 ml] low-dose group versus 920 ml (350 to 2700 ml) control group, p < 0.001). There was no difference between the two aprotinin groups. The need for postoperative blood transfusion was significantly lower in the aprotinin groups (1.46 [0 to 4] blood units high-dose group and 1.65 [0 to 5] blood units low-dose group versus 2.43 [0 to 7] blood units control group, p < 0.05). All patients underwent coronary angiography between the seventh and twelfth postoperative day. No difference was found among the three groups in patency of vein grafts-93.8% in the high-dose group, 94.5% in the low-dose groups, and 93.3% in the control group. Therefore, aprotinin significantly reduced postoperative bleeding and transfusion requirement after coronary artery bypass grafting without influencing early graft patency.

Sinus of Valsalva aneurysm: a late complication after repair of ascending aortic dissection

Surgical advances and the introduction of new more rapid and accurate diagnostic techniques have led to significant improvement in the survival of patients with aortic aneurysms. However, considerable long-term morbidity and mortality remains a concern. In the present study we report on the occurrence of sinus of Valsalva (SV) aneurysm after repair of the ascending aorta for aortic dissection as a significant long-term complication. Since transesophageal echocardiography (TEE) became available it has been used for the follow-up of 33 hospital survivors after ascending aortic replacement for a mean of 27 +/- 20 months. Those patients who received a valved conduit were excluded from this analysis. The aortic valve was conserved in 22 patients: 17 had a dissecting aneurysm involving the ascending aorta and 4 patients non-dissecting aneurysms. A sinus of Valsalva diameter > 45 mm was considered an aneurysm and was found in a total of 7 patients (33%), 5 being patients with aortic dissection. The overall reoperation rate on account of SV aneurysms was 24%. We conclude that SV aneurysm is a significant long-term complication of patients after repair of the ascending aorta. In the light of these results we have changed our operative policy of repair to include resorcin glue as a reinforcing agent or to perform more extensive repair.

Intramedullary pressure changes and fat intravasation during intramedullary nailing: an experimental study in sheep

In this study, intramedullary reaming and nailing were performed following the insertion of pressure transducers in intact tibias and femora. The femur and tibia were instrumented in 12 sheep (group I) and both tibiae in four (group II). The eight procedures of group II were monitored additionally using echocardiography to detect emboli. Intravasation of fat globules was demonstrated in the blood by the Gurd test and correlated with intramedullary pressure and with echocardiographic monitoring in group II. Medullary nailing was found to be always associated with a severe increase in intramedullary pressure, reaching an average of 1126 mm Hg (304 to 1450 mm Hg) in the tibia and of 753 mm Hg (310 to 1126 mm Hg) in the femur during the first reaming procedures. Particle or fat intravasation was greatest during nail insertion. This phenomenon did not depend on the rise in intramedullary pressure. Our findings indicate that fat and bone marrow intravasation occurs during reaming and nailing in long bones. The maximum embolization of marrow contents demonstrated by echocardiography is seen during nail insertion independent of the changes in intramedullary pressure.