Androgen response in polycystic ovarian syndrome to FSH treatment after LHRH agonist suppression.

Anovulatory patients with clomiphene-resistant polycystic ovarian syndrome were treated by two different stimulation protocols. Follicular maturation was induced in 14 women with hMG; 12 of them received pure FSH in a later series after previous pituitary desensitization with the LHRH agonist D-Trp-6-LHRH (Decapeptyl). Both basal and stimulated serum androstenedione, testosterone, and free testosterone were elevated in the hMG-treated group compared with controls. However, only androstenedione exhibited a significant increase between early and late follicular levels. Marked suppression of these androgens has been observed after two weeks of LHRH agonist pretreatment, but nearly the same concentrations were obtained with pure FSH on the day of hCG administration. Again, only the increase of androstenedione levels proved to be significant. Polycystic follicular maturation, hyperstimulation, and peak estradiol levels were comparable with the two protocols. Nevertheless, more pregnancies were achieved using the LHRH agonist+FSH combination (4 vs. 1). It is suggested that 2 weeks' suppression of ovarian androgens with LHRH agonist is not sufficient to neutralize the unfavourable intraovarian mechanisms interfering with normal folliculogenesis. More data are required to confirm the superiority of LHRH agonist pretreatment in the management of polycystic ovarian syndrome.


Pantalar and tibiotalocalcaneal arthrodesis for post-traumatic osteoarthrosis of the ankle and hindfoot.

Twenty-one patients had a unilateral extended arthrodesis of the ankle and hindfoot (a tibiotalocalcaneal procedure in thirteen patients and a pantalar procedure in eight) for post-traumatic osteoarthrosis or deformity, or both. The operation was performed through a transfibular extended lateral approach, and autogenous bone graft and rigid internal fixation was used. A final alignment of 0 to 5 degrees of valgus, 0 to 5 degrees of calcaneus, and external rotation equal to that of the contralateral side was sought. Subjective and objective evaluation, including a personal interview, physical examination, and radiographic and dynamic pedobarographic analysis, was performed at a mean interval of thirty-two months (range, twenty-four to fifty-four months) after the operation. A solid fusion was achieved in eighteen (86 per cent) of the twenty-one patients. There were five malunions (24 per cent) and two superficial wound problems (10 per cent). Of the seventeen patients who were not retired from work, eleven returned to work: nine to an occupation that involved standing and two to a sedentary occupation. Although seventeen (81 per cent) of the twenty-one patients reported that they were much improved, twenty (95 per cent) had some pain, and most benefited from modifications in shoe-wear. Patients who had had a tibiotalocalcaneal arthrodesis were more mobile and functioned at a higher level than those who had had a pantalar arthrodesis. Extended arthrodesis of the ankle and hindfoot is a complex, technically demanding procedure, and should be regarded as a salvage operation capable of producing a satisfactory result and usually providing a reasonable alternative to amputation.


The establishment of polarized membrane traffic in Xenopus laevis embryos.

Delineation of apical and basolateral membrane domains is a critical step in the epithelialization of the outer layer of cells in the embryo. We have examined the initiation of polarized membrane traffic in Xenopus and show that membrane traffic is not polarized in oocytes but polarized membrane domains appear at first cleavage. The following proteins encoded by injected RNA transcripts were used as markers to monitor membrane traffic: (a) VSV G, a transmembrane glycoprotein preferentially inserted into the basolateral surface of polarized epithelial cells; (b) GThy-1, a fusion protein of VSV G and Thy-1 that is localized to the apical domains of polarized epithelial cells; and (c) prolactin, a peptide hormone that is not polarly secreted. In immature oocytes, there is no polarity in the expression of VSV G or GThy-1, as shown by the constitutive expression of both proteins at the surface in the animal and vegetal hemispheres. At meiotic maturation, membrane traffic to the surface is blocked; the plasma membrane no longer accepts the vesicles synthesized by the oocyte (Leaf, D. L., S. J. Roberts, J. C. Gerhart, and H.-P. Moore. 1990. Dev. Biol. 141:1-12). When RNA transcripts are injected after fertilization, VSV G is expressed only in the internal cleavage membranes (basolateral orientation) and is excluded from the outer surface (apical orientation, original oocyte membrane). In contrast, GThy-1 and prolactin, when expressed in embryos, are inserted or released at both the outer membrane derived from the oocyte and the inner cleavage membranes. Furthermore, not all of the cleavage membrane comes from an embryonic pool of vesicles--some of the cleavage membrane comes from vesicles synthesized during oogenesis. Using prolactin as a marker, we found that a subset of vesicles synthesized during oogenesis was only released after fertilization. However, while embryonic prolactin was secreted from both apical and basolateral surfaces, the secretion of oogenic prolactin was polarized. Oogenic prolactin was secreted only into the blastocoel (from the cleavage membrane), none could be detected in the external medium (from the original oocyte membrane). These results provide the first direct evidence that the oocyte synthesizes a cache of vesicles for specific recruitment to the embryonic cleavage membranes which are polarized beginning with the first cleavage division.


Genetic linkage of recessive dystrophic epidermolysis bullosa to the type VII collagen gene.

Generalized mutilating recessive dystrophic epidermolysis bullosa (RDEB) is characterized by extreme skin fragility owing to loss of dermal-epidermal adherence. Immunohistochemical studies have implicated type VII collagen, the major component of anchoring fibrils, in the etiology of RDEB. In this study, we demonstrate genetic linkage of the type VII collagen gene and the generalized mutilating RDEB phenotype. We first identified a Pvull polymorphic site by digestion of an amplified product of the type VII collagen gene, which was shown to reside within the coding region. Genetic linkage analysis between this marker and the RDEB phenotype in 19 affected families which were informative for this polymorphism showed no recombination events, and gave a maximum lod score of 3.97 at a recombination fraction (theta) of 0, demonstrating that this DNA region is involved in this form of RDEB. These data provide strong evidence that the type VII collagen gene, which has also been linked with the dominant form of the disease, harbors the mutation(s) causing the generalized mutilating form of RDEB in these families, thus underscoring the major functional importance of type VII collagen in basement membrane zone stability.


Tyrosine hydroxylase and acetylcholinesterase in the domestic pig mesencephalon: an immunocytochemical and histochemical study.

The mesencephalon of the young domestic pig was studied by tyrosine hydroxylase (TH) immunocytochemistry and acetylcholinesterase (AChE) histochemistry with focus on the substantia nigra (SN), the ventral tegmental area (VTA), and related areas. The purpose was to obtain information on the organization of the mesencephalic, TH immunoreactive (TH-i), and dopaminergic areas of the pig, in order to provide the necessary background for the possible use of the pig as an alternative large animal experimental model for research on Parkinson's disease, including the use of encapsulated pig dopaminergic neurons for intracerebral xenotransplantation. Significant findings in the pig, compared to observations in other species, included the presence of prominent bundles of TH-i dendrites passing in a dorsoventral direction from pars compacta into pars reticulata at middle and caudal levels of the SN, and the presence of a distinct TH-i substantia nigra pars lateralis (SNL). Caudally in the pig mesencephalon, the retrorubral field (RRF) was found to be very extensive. The view of the RRF, SN, and VTA as parts of the same integrated system was indicated by the crisscrossing of TH-i dendrites at the transitions between these areas. Estimation of the number of TH-i neurons in the SN and the VTA showed that these nuclei were of equal size in the pig. Further, it was found that TH-i nerve cells were present in the midline between the VTA in the interfascicular and rostral linear groups. TH-i nerve cells were also present in the otherwise serotoninergic dorsal raphe nuclei, just as other TH-i cells formed a perirubral cell group. AChE-positive neurons were present in both SN and VTA, and appeared to have the same size and morphology as the TH-i neurons in these areas. Within both nuclei, there were local differences in the AChE staining density, but perhaps more significantly were some marked differences in the structure of the AChE-positive neuropil of the two areas. We anticipate that the present description of the cellular organization of the TH-i dopaminergic areas in the domestic pig ventral mesencephalon will be useful for the development of a nonprimate, large animal, experimental model of Parkinson's disease.


Powders, composed of chlorine-releasing agent acrylic resin mixtures or based on peroxygen compounds, for spills of body fluids.

The use of powders, composed of a mixture of a chlorine-releasing agent with highly absorbent acrylic resin, for disinfecting body fluid spills was evaluated by laboratory tests. 'Encap' and 'Red Z' were found to absorb rapidly up to 200 ml of water to form a semi-solid gel. When experimental formulations containing 1%, 5% and 10% available chlorine were evaluated by a standardized surface test, those containing 10% gave the best results. The ease and rate of absorption of fluids by these formulations decreased as the fluid consistency increased and they seem more suitable for watery spills than for blood. The use of a powder based on peroxygen compounds ('Virkon') for disinfecting contaminated spills was evaluated by laboratory tests and hospital trials. Laboratory tests showed that 'Virkon' is strongly and rapidly bactericidal. In hospital ward trials by nurses using 'Virkon' on both natural and artificial spills, 60 of 62 contact plates pressed on to decontaminated surfaces proved negative, and no unpleasant fumes were generated when 'Virkon' was applied to urine. In another trial, 1% 'Virkon' solution proved very effective in decontaminating mortuary tables. Antiviral activity was not tested.


A new standard for sterility testing for autoclaved surgical trays.

Sterility testing on autoclaved surgical trays provides scientific information on the duration for which an item can be safely stored. Previous studies were performed by sampling at various time-points after storage and did not take into account potential injuries (moving, lifting etc.) to these trays as they occur in a clinical setting. A standardized protocol was developed by an expert panel based on events which were frequently observed in the Central Sterilization area. We tested 600 samples in 100 surgical trays that were moved and transported according to the standardized protocol. Moved surgical trays were contaminated in 8.3% of tests, a figure much higher than that reported by previous studies. These data suggest that current standards for sterility testing of autoclaved surgical trays can be improved by the addition of event-related testing.


An 11-month incidence study of infections in wards of a district general hospital.

Between March 1988 and January 1989, an incidence study of infections in patients occupying 122 beds in a district general hospital was undertaken. Nursing notes, medical notes, temperature charts, drug prescription charts and laboratory information were reviewed three times a week to determine if patients had infection which met strict case definitions. In addition, the surveyor consulted with ward nursing and medical staff for clarification of symptoms and signs indicative of infection. During the study, 668 infections were identified amongst 3326 patients. Three hundred and thirty-eight (51%) were community-acquired infections (CAI) and 330 hospital-acquired infections (HAI). Excluding 24 HAI acquired in other hospitals, the incidence rates were 9.2 HAI per 100 discharges, and 1.1 HAI per 100 patient days. The common types of CAI were pneumonia, abdominal infection and urinary tract infection. The main types of HAI were urinary tract infection, surgical wound infection and pneumonia. The microorganisms most frequently associated with CAI and HAI were Gram-negative bacilli.


An analysis of the microbial flora of premature neonates.

An analysis of the microbial flora of 10 premature neonates hospitalized in a neonatal intensive care unit (NICU) was made. The babies had received neither antibiotics nor antiseptics and nine out of 10 were born by caesarean section. Samples were collected on the fourth or fifth day of life from 18 skin or mucosal sites. Detailed bacterial counts were obtained by plating out suitable dilutions of the samples on to selective media. Representative samples of each colony type were then subcultured and identified, using standard laboratory methods. Two hundred and fifty-six isolates of staphylococci were obtained and their susceptibility to 23 antibiotics tested. Only 11% of the samples were sterile. Coagulase-negative staphylococci (CNS) were the commonest species isolated and were predominant in every site studied. They were found in 79% of the samples and represented almost 81% of the neonates' flora. Eight species and biotypes of CNS were identified. In decreasing order of frequency, they comprised S. epidermidis (biotypes 1 and 2), S. hominis (biotype 1), S. warneri, S. haemolyticus, S. capitis, S. cohnii and S. hominis (biotype 2). CNS distribution appeared to be highly heterogeneous with no significant specificity of any species for a particular body site. The main quantitative and qualitative variations seemed to relate to the method of delivery, and the intensity and nature of exposure of the neonate to its local environment. A high level of antibiotic resistance was found among the CNS isolates (especially S. epidermidis and S. haemolyticus): penicillin G (96%), oxacillin (31%), erythromycin (52%) and gentamicin (28%). Moreover, multiresistant strains were numerous, supporting the nosocomial origin of CNS.


CT evaluation following Whipple procedure: potential pitfalls in interpretation.

A series of 41 CT examinations in 14 patients who had undergone a Whipple procedure for pancreatic cancer followed by adjuvant chemotherapy and radiation therapy were reviewed to determine the spectrum of CT findings, as well as to identify potential sources of error in interpretation. Thickening of the wall of the gastric antrum and proximal duodenum from 5 to 10 mm (9 of 14 patients) occurred as early as 1 month after completion of radiotherapy and simulated recurrent tumor. Unopacified anastomotic bowel loops in the porta hepatis in 23 of 41 examinations (56%) also mimicked recurrent tumor or adenopathy. Five of 14 patients showed liver metastases and 4 of 14 had recurrent disease in the pancreatic bed. Pneumobilia (33 of 41 examinations) was a frequent normal finding.


In-vitro evaluation of povidone-iodine and chlorhexidine against methicillin-resistant Staphylococcus aureus.

The in-vitro activity of povidone-iodine (PVP-I) and chlorhexidine (CHX) against 33 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) was evaluated by a quantitative suspension test method. Bactericidal potency was measured by the logarithmic reduction factors (LRFs) achieved with each strain, tested at dilutions 25-800 over exposure times 30-300 s using a challenge of approximately 10(7) colony forming units (cfu) ml-1. The mean LRFs achieved over all dilutions, times and strains were significantly higher for PVP-I than CHX. PVP-I exhibited a superior killing effect whether measured by rate of kill or final LRF achieved. This difference was highly significant as judged by analysis of variance (P less than 0.001). Full efficacy of an antiseptic has been defined as a safe LRF greater than five. Over the dilution range 25-200 this was achieved by CHX with only three of 33 strains. In contrast, PVP-I achieved full efficacy with all 33 strains.


Melioidosis and safety in the clinical laboratory.

Human infection with Pseudomonas pseudomallei, the causative agent of melioidosis, typically produces subclinical disease and an asymptomatic carrier state; occasionally clinical illness, frequently with a fatal outcome, may occur. Consequently, to help protect staff from laboratory-acquired melioidosis, microbiological and biomedical laboratories must have adequate facilities for safe work procedures and laboratory staff must engage in safe work practices. Recommendations from a melioidosis-endemic, diagnostic laboratory for the prevention of laboratory-acquired infection with this bacterium are essentially Category 3 (Advisory Committee on Dangerous Pathogens), Risk Group 3 (Australian Standards) or Biosafety Level 2 (National Institutes of Health) precautions. These include safeguards for centrifugation, prohibiting the 'sniff' test and the use of a biological safety cabinet for sputum processing, for subculture of stock strains, for preparation of antigen and for research studies but not for routine diagnostic techniques with P. pseudomallei.


Lectinophagocytosis of type 1 fimbriated (mannose-specific) Escherichia coli in the mouse peritoneum.

Bacteria can bind specifically to phagocytic cells via lectin-carbohydrate interactions and such binding is often followed by activation and degranulation of the phagocytes, as well as uptake and killing of the bacteria, a phenomenon designated lectinophagocytosis. Although extensively studied in vitro, no direct evidence for the occurrence of lectinophagocytosis in vivo has been available. To obtain such evidence, we injected type 1 fimbriated (mannose-specific) or nonfimbriated Escherichia coli into the peritoneal cavity of mice (10(7)-10(10) bacteria/animal) in the absence or presence of sugars and quantified the phagocytic activity by assaying the release of lysosomal N-acetyl-beta-D-glucosaminidase into the peritoneal fluid, up to 45 min after injection. Following injection of the type 1 fimbriated bacteria, significant release of the enzyme was observed which was time dependent and increased with the number of bacteria injected, whereas the nonfimbriated bacteria caused only little release. Methyl alpha-D-mannoside (50 mM), but not methyl alpha-D-galactoside or sucrose, inhibited the release by 60 to 100%. No release of N-acetyl-beta-D-glucosaminidase was induced by bacteria injected into a peritoneal cavity from which the macrophages had been removed. Our findings show that lectinophagocytosis can occur in vivo and may contribute to the host's defence against type 1 fimbriated bacteria.


Effects of gold(I) antiarthritic drugs and related compounds on Pseudomonas putida.

The effects of the antiarthritic drugs aurothiomalate (AuTm), aurothioglucose (AuTg), auranofin, its metabolite triethylphosphinegold(I)thioglucose (Et3PAuTg), and several related complexes on the growth of Pseudomonas putida were studied. Two strains were used, one of which (BK135) was more sensitive to Et3PAuTg (tolerant up to 4 microM) than the other (BK403; tolerant to at least 500 microM). Gold thiolate complexes and thiolate ligands alone had little effect on growth. Gold phosphine complexes increased the length of the lag phase of growth and reduced oxygen uptake. Marked changes in cellular morphology were determined by electron microscopy. Copper(II) compounds and aurothiomalate were synergistic in their growth inhibitory effects towards these bacteria. Experiments with 195Au suggested that a mechanism does not exist for the short term (minutes) uptake of gold by sensitive or resistant bacteria, but the resistant strain appeared to limit gold uptake over a longer term (hours).


Prediction of affected MEN2A gene carriers by DNA linkage analysis for early total thyroidectomy: a progress in clinical screening program for children with hereditary cancer syndrome.

The gene predisposing to multiple endocrine neoplasia type 2A (MEN 2A) has been assigned to chromosome 10, and affected gene carriers can be identified before the development of associated malignancy in some informative families. We applied these advances in gene mapping to clinical screening for possible pediatric surgery. A family with MEN 2A, consisting of 88 members and their spouses, was studied to test the reliability of the provocation of plasma calcitonin with pentagastrin and the possibility of DNA diagnosis of mutated gene carriers with DNA probes closely linked to the MEN2A gene including RBP3 and FNRB genes. Nineteen of the 88 were diagnosed as MEN 2A carriers. Twelve of them were treated surgically and the others died of medullay thyroid carcinoma (MTC) or pheochromocytoma. A strikingly sensitive response of calcitonin was observed in all those with MTC. The genotypes cosegregating with the abnormal allele at MEN2A in this family could be deduced from clinically established affected members. The early detection of gene carriers allows us to concentrate our screening efforts on children at high risk and to release non gene carriers from repeated unnecessary testing. MEN2A is one of the first cancer syndromes for which DNA screening permits early detection of members at high risk.


High-performance liquid chromatographic method for determination of ronactolol in urine and plasma: evaluation of pharmacokinetic parameters in healthy humans.

Ronactolol [(+/-)-4'-[2-hydroxy-3-(isopropylamino)propoxy]-p-anisanilide], a new aminopropanol derivative showing beta-adrenoreceptor blocking activity, was administered orally as capsules to healthy humans at three single doses (30, 60, and 120 mg). Two HPLC methods were developed separately for determination of drug levels in urine and plasma. For plasma samples, after addition of internal standard (IS), a single-step extraction of alkalinized plasma was performed with methylene chloride. The organic layer was evaporated to dryness under reduced pressure, and the residue was taken up and chromatographed on a microbore silica column. Ronactolol and IS were detected by a UV detector at a wavelength of 278 nm. Excellent linearity was observed between the peak height ratios (ronactolol:IS) and concentrations in plasma. The lowest limit of detection (signal:noise, 3:1) was 1.5 ng/mL of plasma. Urine samples were directly injected and chromatographed on a microbore C18 column with an ion-pairing mobile phase. Excellent linearity was observed between the peak areas and concentrations in urine. The lowest limit of detection (signal:noise, 3:1) was 75 ng/mL of urine. The assay was used to determine the main pharmacokinetic parameters in healthy humans.


Two types of glutamate receptors differentially excite amacrine cells in the tiger salamander retina.

1. Excitatory inputs to amacrine cells in the salamander retinal slice preparation were examined using whole-cell patch pipette voltage-clamp techniques. In strychnine (500 nM) and bicuculline (100 microM), two types of amacrine cell were easily distinguished by their light-evoked excitatory responses: transient and sustained. 2. In transient amacrine cells the current-voltage (I-V) relation for the peak light-evoked current was non-linear with a negative slope region between -50 and -70 mV. Responses reversed near +10 mV and were prolonged at more positive holding potentials. 3. In DL-2-amino-phosphonoheptanoate (AP7, 30 microM), a selective N-methyl-D-aspartate (NMDA) receptor antagonist, both the negatively sloped region of the light I-V relation and the prolongation of the response at positive potentials were eliminated. In 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 2 microM), a selective non-NMDA receptor antagonist, light-evoked currents at the most hyperpolarized holding potentials were eliminated. At potentials positive to -85 mV the light-evoked currents lacked a fast onset. The light I-V relation in CNQX had a negative slope region between -35 and -80 mV. 4. With synaptic transmission blocked, kainate evoked responses in transient cells with a resultant I-V relation that was nearly linear, whereas glutamate and NMDA elicited responses with non-linear I-V relations. 5. Light-evoked currents in sustained amacrine cells had a nearly linear I-V relation and reversed near +10 mV. AP7 at a concentration of 30 microM did not affect the light-evoked currents in sustained cells, but 2 microM-CNQX eliminated all light-evoked currents in these cells. 6. With synaptic transmission blocked, sustained amacrine cells responded only to glutamate and kainate, not NMDA. The resultant I-V relations were linear. 7. We conclude that the light-evoked responses of transient amacrine cells are mediated by concomitant activation of both non-NMDA and NMDA receptors whereas the responses of sustained amacrine cells are mediated only by non-NMDA receptors. Furthermore, these data provide supportive evidence that the primary light-evoked excitatory neurotransmitter activating amacrine cells is glutamate.


HIV-associated oral lesions; immunologic, virologic and salivary parameters.

There are numerous reports of oral lesions in HIV-infected individuals. However, few correlate the oral lesions with laboratory parameters. This study examined oral candidiasis and hairy leukoplakia, the two most common HIV-associated oral lesions, in relation to T-cell counts, p24 core antigen levels and salivary flow rates. Oral mucosal examinations, immunologic and virologic studies and stimulated whole and parotid saliva flow rates were conducted on 135 (HIV+ = 102, HIV- = 33) homosexual or bisexual men. Results indicate that, among HIV-infected subjects, the odds of having oral candidiasis is 6 times (95% CI = 0.6-56.6) greater for subjects with T4 counts between 200-399 per mm3, and 23 times (95% CI = 2.8-193.0) greater for subjects with T4 counts less than 200/mm3 compared to subjects with T4 counts of 400/mm3 or greater. Subjects had an equal likelihood of having hairy leukoplakia at different levels of immunocompetence. The prevalence of oral candidiasis and hairy leukoplakia was higher among subjects with infectious virus in their serum, but was only statistically significant for hairy leukoplakia (p = 0.01).


Presence of expression products of c-erbB-1 and c-erbB-2/HER2 genes on mammalian sperm cell, and effects of their regulation on fertilization.

The present study was conducted to investigate the presence of expression products of c-erbB-1 and c-erbB-2/HER2 genes on mammalian sperm cell, and study the effects of their antibodies on fertilization. The mature sperm cells from various mammalian species (human, mouse, rabbit and rat) were found to have EGF-receptors but not the p185HER2 molecules by indirect immunofluorescence technique (IFT) and Western blot procedure. Though the EGF-receptors present on sperm cells were functionally active and responded to ligand binding, their activation by EGF or blocking by antibodies did not affect the sperm cells in acquiring their fertilization potential. These results indicate that the products of c-erbB-1 and c-erbB-2/HER2 genes, though they have been shown to have tyrosine kinase enzyme activity, do not seem to play a major role in the development of the fertilizing capacity of sperm cells.


Expression of the CD11/CD18 cell surface adhesion glycoprotein family and MHC class II antigen on blood monocytes and alveolar macrophages in interstitial lung diseases.

The expression of molecules of the CD11/CD18 cell surface adhesion glycoprotein family and HLA/DR antigen was studied on peripheral blood monocytes (PBM) and alveolar macrophages (AM) in bronchoalveolar lavage (BAL) fluid from patients with sarcoidosis, idiopathic pulmonary fibrosis (IPF), and extrinsic allergic alveolitis (EAA). Patients with these interstitial lung diseases showed increased numbers of macrophages in BAL fluid. This was probably caused by an increased influx of PBM to the alveoli since the numbers of cells with a monocytic morphology were also significantly increased in BAL samples from patients with interstitial lung disease, most prominently in IPF and EAA. The increased influx of PBM into the alveoli in patients with interstitial lung diseases was not reflected by an increased expression of the CD11/CD18 leukocyte function antigens on PBM. In healthy volunteers as well as in those with sarcoidosis, IPF, and EAA, the percentages of AM positive for CD11b (the C3bi complement receptor) and CD11c were lower than among PBM. This indicates that the expression of these cell surface adhesion molecules is downregulated during maturation and migration of PBM to the alveoli. The absolute numbers of AM positive for CD11b were increased in BAL fluid of IPF and EAA patients compared to healthy volunteers. EAA patients also showed increased absolute numbers of AM positive for CD11a and CD11c. This differentially increased expression of these leukocyte function antigens on AM suggests the influence of locally produced cytokines.


Zinc supplements in breastfed infants.

Among breastfed infants, growth faltering in comparison with reference growth curves is common in both developing and developed countries. We performed a zinc supplementation trial in Paris, France, to find out whether such growth faltering is due to nutritional zinc deficiency. 57 breastfed infants aged 4-9 (mean 5.7) months were randomly assigned to receive either 5 mg zinc daily or a placebo for 3 months. Most of the infants were from low-income immigrant families and the majority were of African origin. Before supplementation there were no significant differences between the zinc and placebo groups in weight, length, or corresponding Z-scores for age. After 3 months' supplementation, the length-for-age Z-score had increased in the zinc group and fallen in the placebo group (+0.21 vs -0.13, p = 0.029). This difference was due mainly to greater linear growth of boys in the zinc than in the placebo group (6.0 vs 4.6 cm, p = 0.02). Weight gain was also significantly greater with zinc supplementation (1.64 vs 1.28 kg, p = 0.047). Among infants breastfed for longer than 4 months, decreases in growth velocity result partly from inadequate zinc intake.


Safety and immunogenicity of single-dose live oral cholera vaccine CVD 103-HgR in 5-9-year-old Indonesian children.

Oral vaccines offer great promise as public-health measures to prevent disease in less-developed countries. CVD 103-HgR, a genetically engineered, attenuated, Vibrio cholerae O1 strain has proved effective in industrialised countries. We have assessed the safety, immunogenicity, and excretion of this live cholera vaccine in children in north Jakarta, Indonesia. 412 children aged 5-9 years received single doses of 5 x 10(6), 5 x 10(7), 5 x 10(8), 5 x 10(9), or 1 x 10(10) colony forming units (CFU) of CVD 103-HgR or placebo (5 x 10(8) inactivated Escherichia coli K-12) with buffer. All doses were well tolerated. The 5 x 10(8) CFU dose, which is highly immunogenic in subjects in industrialised countries (greater than 90% seroconversion), elicited seroconversions of vibriocidal antibody in only 16% of Indonesian children. By contrast, a single 5 x 10(9) CFU dose of vaccine resulted in high rates (75% and 87%) of seroconversion with two different batches of vaccine. A batch prepared with a centrifugation step gave significantly higher geometric mean titres (16-fold increase over baseline) than did a batch in which there was a filtration step between fermentation and lyophilisation (10-fold increase over baseline). At a 5 x 10(9) CFU dose, CVD 103-HgR is well tolerated and highly immunogenic in Indonesian children and should therefore be further investigated for use as a one-dose live oral cholera vaccine in developing countries.


Effects of exposure to benzodiazepine during fetal life.

Dysmorphism and mental retardation have been reported in 7 Swedish children born of mothers who had taken high doses of benzodiazepines regularly during pregnancy. To explore this association further, we examined benzodiazepine use during pregnancy in 104,000 women whose deliveries were registered by the US public health insurance system, Medicaid, during 1980-83. Fetal outcomes were assessed from the health claims profiles of their offspring, up to 6-9 years after delivery. 80 pregnant women had received 10 or more benzodiazepine prescriptions during the 4 years. Their records showed heavy general use of health care and frequent alcohol and substance abuse, and other disorders that could confound any effect of the benzodiazepines. For the 80 pregnancies, 3 intrauterine deaths were identified as well as 2 infants with congenital abnormalities whose curtailed records suggested neonatal death. Records of 64 surviving children could be linked to these 80 pregnancies whilst records for 11 apparent survivors could not be located. 6 of the 64 survivors had diagnoses consistent with teratogenic abnormalities. The high rate of teratogenicity after heavy maternal benzodiazepine use occurs with multiple alcohol and substance exposure and thus may not be due to benzodiazepine exposure.


Stereoselective release of (S)-atenolol from adrenergic nerve endings at exercise.

In-vitro studies have shown that atenolol, a beta-blocking agent, is stereoselectively taken up by and released from adrenergic nerve endings by membrane depolarisation. To investigate the potential importance of these findings, blood samples were taken at rest and after exercise testing from 10 patients (mean [SE] age 60 [3] years) receiving long-term treatment with racemic atenolol. At rest, mean plasma concentration of (R)-atenolol was higher than that of (S)-atenolol (ratio 1.14, p less than 0.01), but after exercise there was a stereoselective increase in (S)-atenolol concentration, which changed the ratio to 0.66 (p less than 0.01). Since (S)-atenolol but not (R)-atenolol causes clinically relevant beta-blockade, our findings may have importance for the management of patients receiving beta-blocking drugs.


Hepatitis C viraemia and liver disease in symptom-free individuals with anti-HCV.

There is controversy about clinical management of patients who persistently have antibodies to hepatitis C virus (anti-HCV) but who have no symptoms and signs of liver disease. We have taken liver biopsy samples from 23 such patients (16 of whom had normal alanine aminotransferase [ALT] values) to assess prevalence of liver disease and to see whether anti-HCV and HCV-RNA correlated with histological findings. 16 patients had histological evidence of chronic hepatitis, which was not predicted by serum ALT or by the pattern of specificity of anti-HCV. All 16 cases with hepatitis C viraemia (HCV-RNA detected by polymerase chain reaction), including 9 with normal ALT, had chronic hepatitis on biopsy (p less than 0.001), whereas 7 HCV-RNA-negative cases had normal liver histology. These findings indicate that serum HCV-RNA is a sensitive and specific marker of liver disease in anti-HCV-positive subjects, independent of ALT values, and challenge the idea of the existence of "true" healthy carriers of HCV.


Ultrasonographically detectable markers of fetal chromosomal abnormalities.

Screening for fetal chromosomal abnormalities on the basis of maternal age has not resulted in a substantial fall in the proportion of infants born with an abnormal karyotype. Most fetuses with major chromosomal abnormalities have defects that can be recognised on detailed ultrasonographic examination. Therefore, provided the cardinal signs of each chromosomal syndrome are recognised, it is possible that screening by ultrasound examination could have a greater impact. We karyotyped 2086 fetuses after ultrasonographic examination had revealed fetal malformations, growth retardation, or both. Chromosomal abnormalities were detected in 301 (14%) cases and were more common among fetuses with multisystem malformations (29%) than among those with isolated defects (2%). The commonest chromosomal abnormality was trisomy 18, followed by trisomy 21, triploidy, Turner's syndrome, unbalanced chromosomal rearrangements, and trisomy 13. Trisomy 18 was associated with strawberry-shaped head, choroid plexus cysts, facial cleft, micrognathia, heart defects, exomphalos, malformations of hands and feet, and growth retardation. In trisomy 21, the associated defects were subtle and included nuchal oedema, macroglossia, atrioventricular septal defects, mild hydronephrosis, clinodactyly, and sandal gap. The frequency of autosomal abnormalities increased with maternal age, but if fetal karyotyping had been restricted to mothers older than 35 years, large proportions of chromosomally abnormal fetuses would not have been diagnosed prenatally (64-97%). Our findings provide guidelines as to which defects to search for in screening studies for the detection of chromosomal abnormalities.


HIV infection at outcome of pregnancy in the Paris area, France.

The prevalence of HIV infection in women at end of pregnancy, irrespective of outcome, was determined in a comprehensive survey of both women and medical centres during successive 4-week periods in four areas of the Paris region, France. Blood samples were tested anonymously for antibodies to human immunodeficiency virus (HIV)-1 and HIV-2. Of the 11,593 blood samples 0.40% (95% confidence interval [CI] 0.28-0.51) were positive for HIV-1 and 0.02% (95% binomial interval [BI] 0.002-0.065) for HIV-2. Seroprevalence was higher among women with ectopic pregnancy (2%) (95% BI 0.24-7.04); the rate in women having an elective or therapeutic abortion was more than twice that in those delivering babies (0.70% vs 0.28%, p less than 0.05, relative risk 2.54, 95% CI 1.36-4.75). Studies with neonatal HIV seroprevalence as a surrogate for HIV prevalence in pregnant women would underestimate prevalence in these women.


Smoking as "independent" risk factor for suicide: illustration of an artifact from observational epidemiology?

Two widely used criteria for determining whether an association between a risk factor and a disease is causal are dose response and independence from other factors. Data from a large US risk factor study (MRFIT) throw up a relation between cigarette smoking and suicide that meets these criteria, yet appears to be biologically implausible. It is likely that many more such associations, for other exposures and other diseases, are equally spurious, but are protected by their lack of obvious implausibility.


Extraordinary unremitting endurance exercise and permanent injury to normal heart.

This hypothesis is that permanent cardiac injury could develop in some endurance athletes despite the absence of coronary atherosclerosis and ventricular hypertrophy. The proposed mechanism by which this injury could arise involves two physiological "vicious cycles". The first vicious cycle would occur between severe ischaemia and high catecholamines, the second would be between coronary vasospasm (induced by high catecholamines) and endothelial injury. The likelihood of the injury becoming permanent might increase if there is insufficient time between bouts of endurance exercise for regression of ischaemia and endothelial repair. Furthermore, magnesium ion deficiency, which can be induced by exercise, could exacerbate these vicious cycles and also contribute to catecholamine-induced thrombogenesis. In addition to ischaemia, there are several mechanisms, including the effect of free fatty acids liberated by the lipolytic effect of high catecholamines, that could cause direct myocardial injury.


Acute changes in growth hormone-releasing hormone secretion after injection of BIM 23014, a long acting somatostatin analog, in rams.

BIM 23014 is a somatostatin analog displaying an increased biological half life due to resistance to enzymatic degradation. This peptide inhibits GH release directly at the level of pituitary somatotrophs. In addition, an action of BIM 23014 at the level of the hypothalamus is possible since somatostatinergic fibers and receptors have been identified on GH-RH neurons. To evaluate the effect of BIM 23014 on GH-RH secretion, hypophysial portal blood (HPB) was continuously collected in conscious sheep. Twelve rams (40-45 kg, 9-month-old) with chronically implanted perihypophysial cannulae were i.v. injected with BIM 23014 (1 mg) or saline. HPB and jugular blood were collected for 3-5 hours before and after the injection for the determinations of GH-RH and GH concentrations respectively. The acute injection of BIM 23014 induced a rapid decrease of plasma GH within the first two hours. Simultaneously, GH-RH in HPB decreased significantly. After reaching a nadir, GH concentrations increased to values greater than baseline. A similar rebound in GH-RH levels in HPB was also observed. These data indicate that BIM 23014 acts at the level of GH-RH hypothalamic neurons, in addition to its well-know effect on the pituitary gland.


Tyr-MIF-1 and hemorphin can act as opiate agonists as well as antagonists in the guinea pig ileum.

The brain peptide Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) was tested for its effects on electrically stimulated contractions in the guinea pig ileum assay. Tyr-MIF-1 acted as an opiate agonist in reducing these contractions. Its IC50 was about 9 microM, and its effects were reversed by naloxone and CTOP. The ability of Tyr-MIF-1 also to antagonize the inhibitory effects of opiates on electrically stimulated contractions was more evident in the ileum removed from a guinea pig tolerant to morphine or after partial inactivation of opiate receptors with beta-CNA. Similar results were observed with hemorphin. The endogenous peptide Tyr-MIF-1 and the blood-derived peptide hemorphin, therefore, can act as agonists as well as antagonists in the guinea pig ileum. The effects as antagonists are best observed in preparations of ileum with reduced receptor reserve (tolerant or beta-CNA treated) and are consistent with the idea that properties of endogenous peptides as opiate antagonists are enhanced in the tolerant state.


Type 1 pili enhance the invasion of Salmonella braenderup and Salmonella typhimurium to HeLa cells.

The relationship between type 1 pili-associated adhesion and invasion to HeLa cells by Salmonella braenderup and S. typhimurium was studied. When the clinical isolates of these strains were grown in L-broth, they showed both type 1 pili formation and mannose-sensitive adhesion to HeLa cells. On the other hand, the type 1 pili-defective mutants, which were obtained either by repeated subcultures on L-agar plates or by the transposon Tn1-insertion mutagenesis of the S. braenderup and S. typhimurium strains, concomitantly lost mannose-sensitive adhesion to HeLa cells. When the HeLa cells were incubated with Salmonella, the type 1 piliated strains invaded the HeLa cells with much higher infection rate than did the type 1 pili-defective strains. The invasion of type 1 piliated strains to HeLa cells was markedly inhibited in the presence of D-mannose. The infectivity of the strain, which lost type 1 pili but still had mannose-resistant adhesion, was slightly higher than that of the strains defective in both mannose-sensitive and mannose-resistant adhesion. These results suggested that type 1 pili have a role in enhancing the invasion of S. braenderup and S. typhimurium to HeLa cells.


Response to 2-chlorodeoxyadenosine in patients with B-cell chronic lymphocytic leukemia resistant to fludarabine.

Patients with untreated B-cell chronic lymphocytic leukemia have a high rate of complete remission when given the halogenated nucleoside analogue fludarabine. However, patients in whom the disease has proved refractory to primary treatment have a reduced life expectancy and a dismal outcome. We treated four consecutive patients who had unsatisfactory responses to second-line or subsequent treatment with fludarabine with another halogenated nucleoside analogue, 2-chlorodeoxyadenosine. One patient with progressing lymphocytosis, anemia, and thrombocytopenia despite 10 courses of fludarabine entered a complete remission when treated with 2-chlorodeoxyadenosine. Two patients who had less-than-partial remissions after six courses of fludarabine had good partial remissions when treated with 2-chlorodeoxyadenosine. One patient with Coombs-positive hemolytic anemia who had no response to three courses of fludarabine had a partial remission, with resolution of hypogammaglobulinemia, when treated with 2-chlorodeoxyadenosine. There was no evidence of cross-resistance between fludarabine and 2-chlorodeoxyadenosine despite their similar structures. 2-Chlorodeoxyadenosine may induce a complete remission in chronic lymphocytic leukemia that is highly resistant to chemotherapy, and it deserves wider clinical evaluation in patients with this condition.


Infection breaks T-cell tolerance.

Clonal deletion or clonal anergy establish tolerance in T cells that bear potentially autoreactive antigen receptors. Here we report that concomitant infection with the nematode Nippostrongylus brasiliensis breaks an established T-cell tolerance induced by injection of mice with Staphylococcus enterotoxin B (SEB). CD4+ T cells from SEB-tolerant mice did not produce either interleukin-2 or interleukin-4 when challenged in vitro with SEB. N. brasiliensis infection of SEB-primed animals resulted in a normal expansion of SEB-tolerant CD4+V beta 8+ T cells in vivo as well as an equivalent increase of SEB-reactive, interleukin-4-producing CD4+V beta 8+ T cells both in SEB-tolerant and in normal animals. Thus, infection with N. brasiliensis circumvented the tolerance established with SEB. Activation of anergic, potentially autoreactive CD4+ T cells by infectious agents seems to be a major pathway for the initiation of autoimmune diseases. Our results suggest that infectious agents may break tolerance in potentially autoreactive CD4+ T cells by activation of alternative reaction pathways.


Virulent strains of Toxoplasma gondii comprise a single clonal lineage.

The protozoan Toxoplasma gondii is a prevalent parasite in wild and domestic animals worldwide, being transmitted through the food chain by carnivorous feeding and scavenging. Toxoplasma normally divides asexually to yield a haploid form that can infect virtually any vertebrate but it also has a well defined sexual cycle that occurs exclusively in cats. Toxoplasma has become important as an often fatal opportunistic pathogen in patients with AIDS, although the 15-85% of adult human populations that are chronically infected with T. gondii are typically asymptomatic. Infections in immunocompromised hosts have variable outcomes. For example, only 30 to 50% of AIDS patients that are chronically infected with the parasite develop toxoplasmic encephalitis and only about half of acute maternal infections result in congenital disease of the newborn. T. gondii strains differ in their virulence in animals, but the extent to which different strains are related has not been determined. Here we analyse 28 strains from a variety of hosts on five continents and find that the ten virulent strains have an essentially identical genotype, whereas the nonvirulent strains are moderately polymorphic. These data strongly suggest that virulent strains of T. gondii originated from a single lineage which has remained genetically homogeneous despite being globally widespread, and despite the ability of this organism to reproduce sexually.


A meiotic gene conversion gradient opposite to the direction of transcription.

Genetic recombination involves classical crossing-over and gene conversion (aberrant segregation). In fungi that produce an ascus containing four spores, a gene conversion event is manifested as 3:1 or 1:3 (or more rarely 4:0 or 0:4) segregations, in contrast to the normal mendelian 2:2 segregation. Polarity is one of the properties of gene conversion; in almost all cases the frequency of conversion exhibits a gradient across the gene monitored. The frequency of conversion is usually independent of the specific allele used as a marker, but dependent on its location. An interpretation of conversion polarity is that it is caused by the existence of specific initiation sites for meiotic recombination, located at the high end of the polarity gradient. Here we show that the polarity gradient for the HIS2 gene of Saccharomyces cerevisiae is high at the 3' end of the gene, implying that the promoter of HIS2 is not the initiation site.


Coma of vascular aetiology: evaluation and prognosis.

The authors have done a revision of 450 patients admitted during the last 3 years to the emergency service of the Hospital de S. José with the diagnosis of CVA. In this retrospective study were included the patients of greater than or equal to 3 degree of the RLS/85 coma scale, the diagnostic being confirmed by CAT, angiography and/or autopsy, and simultaneously evaluated by the Glasgow coma scale. The studied population was grouped into: SAH; ICH with or without ventricular drowning, cerebellar haematoma, brainstem haematoma, ischaemic CVA. The factors of vascular risk: diabetes and hypertension, the age of the patients and coma level were correlated with the degree of cerebral disability of discharge in all patients. The following factors are clearly related with bad prognosis: coma of degree greater than or equal to 4 in the RLS/85 scale; ischaemic aetiology; intraventricular haemorrhage.


Racial differences in coagulation studies in stroke.

Racial differences in stroke are known to exist with persons in the black race having a higher morbidity, mortality and incidence of stroke compared to whites. We evaluated coagulation factors in black and white stroke patients and compared the results between races. D-dimer was elevated more frequently in blacks than whites to a statistically significant degree. There were non-significant trends for blacks to have a positive lupus anticoagulant, low protein C and protein S, higher platelet factor 4, and hyporesponsive platelets to 10 microM epinephrine. The significance of these findings in understanding racial differences in stroke is discussed.


Heart-brain interactions in cerebral ischaemia: a non-invasive cardiologic study protocol.

The cardiologic evaluation of patients with cerebral ischaemia should be aimed at: (1) identifying potential cardiac sources for cerebral emboli, (2) detecting a coexisting ischaemic heart disease, even asymptomatic. The present data concerns a ten-year experience of a systematic cardiologic evaluation of patients admitted to the 1st Division of Neurosurgery, Bellaria Hospital, Bologna, Italy, for cerebral ischaemia. A two-dimensional echocardiography was carried out in 344 consecutive patients (mean age 53 years), cardiac abnormalities were observed in 92 (28%) out of the 328 cases with technically adequate examination, embologenic lesions in 57 (17%). In 18 cases the cardiac lesion was unknown before the cerebral event. An exercise ECG testing was carried out in 322 patients (mean age 56 years), resulting in abnormal in 69 out of the 258 with adequate examination (17%). A subsequent exercise 201Tl myocardial scintigraphy confirmed the presence of ischaemic heart disease in 58 cases. Among patients unable to perform an adequate exercise, a dipyridamole 201Tl myocardial scintigraphy was performed in 38 cases showing perfusional defects in 23 (60%), while a dipyridamole echocardiography was performed in 25 cases showing wall motion abnormalities in 9 (36%). A 24-h Holter monitoring was performed in 65 cases: arrhythmias were detected in 27 patients (41%), but a correlation with the cerebral event was suggested only in 3 cases with atrial fibrillation. According to our experience patients with recent ischaemia should be submitted to the following non-invasive cardiologic screening: (1) exercise ECG testing followed, if abnormal or indeterminant, by 201Tl myocardial scintigraphy in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)


Cerebral magnetic resonance angiography.

Magnetic resonance angiography (MRA) is an accurate non-invasive tool for imaging the cerebral vessels. It provides morphologic information about the cerebral vessels relying on blood flow as the physical basis for generating contrast between stationary tissues and moving spins. 'Selective' MRA gives functional information about the cerebrovascular system such as flow direction, origin of flow, and presence or absence of collaterals. Arteries and veins can be imaged selectively due to their usually opposite flow directions. Although at a relatively early stage of development, MRA has already become a widely used tool for the study of the cerebrovascular system.


Aging of the serotonergic system in the rat forebrain: an immunocytochemical and neurochemical study.

Age-related changes in both morphological and neurochemical parameters of indol- and catecholaminergic system in the rat brain were examined. A qualitative histochemical survey of the occurrence of aberrant serotonergic fibers in the aged rat brain suggests region-specificity in the process of degeneration. Forebrain areas, such as the caudate-putamen complex, globus pallidus, prefrontal and frontoparietal cortices were consistently affected, whereas serotonergic fibers were only infrequently affected in other areas like septal and amygdaloid nuclei. Neurochemical data similarly revealed regional differences. 5-Hydroxytryptamine levels were increased in the frontoparietal cortex, hippocampus, hypothalamus and the mesencephalic raphe region but remained unchanged in the caudate-putamen complex. 5-Hydroxyindolacetic acid levels were also enhanced in all these areas. Examination of brains of 12-, 18- and 24-month-old rats revealed that aberrant serotonergic fibers were already present at the age of 12 months and their incidence increase with age. There was no difference in the number of serotonergic cells in the dorsal raphe nucleus of young and aged rats. Aberrant tyrosine hydroxylase-immunoreactive fibers were observed only infrequently. Their occurrence showed no overlap with the areas containing aberrant serotonergic fibers. Neurochemical estimates of the levels of catecholamines in young versus aged rat brain areas similarly revealed regional and neurotransmitter specific differences to occur during the process of aging.


Intra- and inter-observer variability of basal flow velocity and vascular reactivity measurements using transcranial Doppler sonography.

The reliability of blood flow velocity measurements performed using transcranial Doppler sonography was investigated with regard to the intra- and inter-observer variability. We compared the flow velocity values recorded in the intracranial vessels by two experienced investigators both under rest conditions and during hypercapnia induced by an apnea test. The results showed how flow velocity values measured at the level of the middle cerebral artery, anterior cerebral artery, ophthalmic artery and basilar artery were not significantly influenced by intra- or inter-examiner variability. The flow velocity increases recorded from the middle cerebral artery during the activation test proved to be reproducible when the measurements were repeated by the same examiner, but more variable when detected by different investigators. On the basis of the available data, the clinical relevance of transcranial Doppler results must take into account the degree of reliability of its measurements.


Tuberoinfundibular dopaminergic neurons and lactotropes in young and old female rats.

Aging in female rats is accompanied by several endocrine dysfunctions, such as reproductive decline associated with characteristic hyperprolactinemia, lactotrope hyperplasia, and functional impairment of hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons. The aim of this morphometrical, immunocytochemical, and densitometrical study was to gain a better anatomical knowledge of TIDA neurons and axons as well as of lactotropes in old female rats with (A) or without (NA) pituitary adenomas, compared with young animals. At the hypothalamic level, we found that tyrosine hydroxylase (TH)-labeled neurons in the arcuate nucleus were comparable in young and old NA yet their size and TH-content were increased in A animals. Also the TH-labeled median eminence axons did not differ significantly between young and old NA but were more numerous in the old A rats. Independently from adenomas, both number of prolactin (PRL)-labeled structures and content of immunoreactive PRL were increased in pituitaries of old rats, the plasma PRL levels, however, were high only in A. Our findings support the documented lactotrope hypertrophy and hyperplasia in old female rats and suggest that TIDA-neuron changes only occur in hyperprolactinemic animals carrier of adenomas.


Age-related decline of cerebral oxygen metabolism in normal population detected with positron emission tomography.

Using positron emission tomography (PET), cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured in 32 healthy volunteers aged from 27 to 67 years. In bilateral putamen, left supratemporal, left infrafrontal and left parietal cortices, CMRO2 showed a significant decline during aging. The age-related decline of CBF was seen only at the left superior temporal cortex. The mean CMRO2 was significantly lower in the elder group (over 51 years old) than in the younger group (under 50 years old), whereas no significant difference in mean CBF between the two groups. The poor correlation of CBF to the age could be explained partly by the fact that CBF is easily influenced by the physiological, psychological and/or environmental factors. The age-related changes of CMRO2 were more marked in the association cortices of the left hemisphere than in that of the right hemisphere.


Functional 3D localization of cerebrovascular accidents by magnetoencephalography (MEG).

Spontaneous magnetic slow wave brain activity can be used to locate the underlying sources with sufficient accuracy by using the single current dipole model. To locate focal sources from spontaneous activity a tool had to be developed to extract focal densities of dipoles across time-the dipole density plot. The first version works on discrete volume units and is used for screening. The second version avoids a possible localization error and works continuously and this even is done on individual slices. The DDP seems to be a valuable tool for extracting and separating different focal sources from the background activity. Not only brain infarctions and haemorrhages (and cysts and angiomas) could be located, but also functional sources associated with TIAs even one week after the symptoms. First results let us assume that clinically silent TIAs also (in analogy to clinically silent brain infarctions) could be detected and located.


Acetazolamide stimulation test in patients with unilateral internal carotid artery obstructions using transcranial Doppler and 99mTc-HM-PAO-Spect.

Fifteen patients with symptoms of cerebral ischaemia and angiographically confirmed unilateral stenoses or occlusions of the extracranial internal carotid artery (ICA) and 20 controls were studied by a 2 MHz transcranial Doppler (TCD) at rest and after stimulation with 1 g acetazolamide i.v., a cerebral vasodilator. In addition, the patients underwent 99mTc-HM-PAO-Spect measurement of regional cerebral blood flow (rCBF) at rest and after stimulation with 1 g acetazolamide. In 10 patients with ICA stenoses greater than 80% or occlusions, time-mean velocity (Vmean) increase and pulsatility index (PI) decrease in the postobstructive middle cerebral artery (MCA) as well as the increase of the ipsilateral rCBF were reduced in comparison with the contralateral side. The remaining 5 patients showed a normal Vmean increase and PI decrease in TCD.


Functional and morphological imaging of small striato-capsular infarction by CT, MRI and multitracer PET.

Regional cerebral blood flow, oxygen consumption, blood volume and glucose metabolism were studied by positron emission tomography (PET) in 16 patients with striato-capsular infarction during the acute phase. Visual evaluation of tomograms and quantitative analysis of PET data detected in all patients severe flow disturbances and metabolic derangement within the territory of the penetrating branches of the middle cerebral artery. Additionally remote effects were observed. The correspondence of early PET changes with the diagnosis of striato-capsular infarction was verified later on by computerized three-dimensional alignment of PET scans and MRI. These results demonstrate that PET allows localization of small striato-capsular infarction with high accuracy in the acute phase by demonstrating both severe local flow disturbances and metabolic derangement, as well as remote effects.


Assessment of intracranial circle after carotid endarterectomy.

To evaluate haemodynamic effects of carotid endarterectomy on cerebral circulation, transcranial Doppler sonography was performed on 69 patients operated for unilateral carotid stenosis greater than 70%. Pre- and post-operative Vm and PI on bilateral middle-cerebral arteries, Vm PI and flow direction on ipsilateral anterior cerebral artery and Vm on basilar artery were evaluated. All patients presented more or less evident preoperative haemodynamic alterations of cerebral circulation and after surgery showed a normal distribution of cerebral blood supply.


Blood flow hydrodynamic resistance in patients with ischaemic stroke or vascular encephalopathy and possibilities of its correction in vitro.

In order to determine the patient blood flow hydrodynamic properties in terms of the Toms-effect, the time blood flow was measured in special apparatus twice: (1) before and (2) after addition of poly(ethylene oxide) WSR-301 (Union Carbide, USA) in concentration of 2 x 10(6) g/ml of blood sample (50 ml with 500 units of heparin) taken from 26 patients with acute ischaemic stroke, 8 patients with vascular encephalopathy after stroke, 5 patients with vascular encephalopathy following atherosclerosis with or without arterial hypertension. The blood samples taken from 8 healthy persons formed the control group. Haematocrit (HCT) and asymptotic blood viscosity were studied also. It was established that hydrodynamic blood flow resistance (HBFR) did not depend on HCT and viscosity, but was significantly higher in all patient groups than in normal persons (p less than 0.05). Addition of polymer solution decreased HBFR of patient blood more intensively that in the control group. We believe that it indicates an insufficiency of an unidentified factor in native human blood.


Modalities of compensation of cerebral circulation through the circle of Willis in stenoses and occlusions of extracranial arteries.

We have studied the intracranial cerebral circulation in 6 patients with bilateral ischaemic lesions of the internal carotid artery in the extracranial segment (2 significant bilateral stenosis cases; 1 case with bilateral thrombosis and 3 cases of unilateral thrombosis and significant contralateral stenosis). All the patients were males, their age being between the 5th and 8th decade. In a single case the neurological examination showed secondary left hemiplegia and recent right paresis of remittent type, while the other 5 patients had only transitory ischaemic attacks with hemiparesis or transitory aphasia. The lesions were revealed by means of duplex system echotomography (Aloka-Hellige Model SSD 630) and spectral analysis of Doppler signal (Vasoscan-Sonicaid) and they were confirmed later by bilateral carotid arteriography in all patients. The intracranial circulation was also followed up by non-invasive methods, making use of spectral-analysis of the Doppler signal with pulsed wave on TC-2 64-B apparatus. The cases studied by us, which present pathogenic situations more rarely encountered, have shown that none of them observed a 'mathematical model' of compensation of blood flow (BF). More exactly, 2 patients with the same type of lesions and topography did not have a unique model of compensation of BF. It seems that both the possibilities of individual self-regulation of cerebral BF and the extracerebral factors, especially those belonging to cardiac activity, are decisive in the compensatory activity of cerebral circulation, while the modalities in which this is accomplished depend chiefly upon the functional condition of the collateral arteries as a whole.


Haemodilution in acute ischaemic stroke comparison of two haemodilution regimen.

In a prospective study we randomly allocated 50 patients with acute ischaemic stroke in the area of the middle cerebral artery within 12 hours after onset to two moderate hypervolemic haemodilution regimen consisting of 500 ml of 10% hydroxyethyl starch per day for 10 days. In the high haematocrit group the target haematocrit of 41-42% was achieved by 0-3 phlebotomies and additional replacement of that volume with the colloid in 3 days. In the low haematocrit group with 1-4 phlebotomies a target haematocrit of 37-38% was reached in 4 days. The groups did not differ regarding age, risk factors, haematocrit and neurological score. The improvement of the disturbed blood rheology was more pronounced in the low haematocrit group. One death occurred in each group. The neurological score showed a significantly greater increase in the low haematocrit group with +59% at day 5 and +125% at day 11; the data for the high haematocrit group were +34% and +89% respectively. We calculated a correlation (r = 0.36, p less than 0.02) between the rise in neurological score and the reduction of haematocrit. Our data suggest but not do prove that an early start on moderate hypervolemic haemodilution is beneficial in patients with acute ischaemic stroke and disturbed blood rheology.


Carotid percutaneous angioplasty.

Clinical benefit from treatment of symptomatic severe carotid stenoses has been demonstrated recently. The safety profile of endarterectomy, however, justifies the development of alternative techniques as percutaneous transluminal angioplasty (PTA), at least in mild to moderate stenoses. Early results and follow-up data from our series of 44 carotid stenoses treated by PTA are reviewed in this paper, in comparison with other reports from literature. PTA may be beneficial as a therapy of symptomatic internal carotid stenoses, provided its cost/effectiveness has been evaluated by a valid method.


Balloon angioplasty for cerebrovascular disease.

Percutaneous transluminal angioplasty (PTA) has become an established treatment for peripheral, renal and coronary vascular disease, where the success rate approaches 90% with complications occurring in less than 5% of patients. There has been a reluctance to recommend PTA of the internal carotid artery (ICA) because of concern about the risks of cerebral embolism. However, there are now a number of reports of technically successful PTA for ICA stenosis, as well as stenosis of other brachiocephalic arteries, demonstrating an improvement in vessel diameter and contour. Complications to date include transient neurological symptoms, asymptomatic carotid dissection and arterial spasm, but the risk of permanent stroke seems to be relatively low. The risks of embolization may be reduced by anticoagulation and avoiding arteries with obvious thrombus or ulceration. Current technical difficulties are likely to be surmounted by improvements in catheter design. PTA is most suitable for smooth ICA stenosis causing haemodynamic symptoms, fibromuscular dysplasia, surgically inaccessible stenosis, and patients with medical risk factors increasing the risks of carotid endarterectomy, such as ischaemic heart disease. Only brief admission is required, avoiding the surgical and anaesthetic risks of carotid endarterectomy. The preliminary results are encouraging enough to set up a randomized trial to determine the risks and benefits. It remains to be seen whether alterations in the calibre or contour of the vessel wall will reduce subsequent stroke. Whether cerebrovascular PTA will enter general use will depend on the balance of the risk-benefit equation.


Local thrombolytic therapy for thromboembolic occlusion of the middle cerebral artery.

We report on 10 patients with thromboembolic occlusion of the middle cerebral artery (MCA) who underwent local thrombolytic therapy. Six patients developed a MCA occlusion during long-standing interventional neuroradiological procedures, while four had a proven or suspected cardio-embolic stroke. Streptokinase or urokinase was applied by a microcatheter placed into the thrombus within six hours of clinical onset. Complete or partial revascularization was achieved in all patients. Recovery was complete in seven and partial in three of the patients. In two patients, minor haemorrhagic transformation of the infarct occurred, which did not lead to neurological deterioration. It is concluded that in a selected group of patients with MCA occlusion, local thrombolytic therapy represents a safe and effective therapy.


Hypervolemic haemodilution and completed stroke: how important is the application time for its effect?

In 75 patients with completed stroke hypervolemic haemodilution was performed for 1 day with 500 ml 6% HES 200.000/0.6-0.66 (Elohäst) to test the acute influence of application time for haemorheological changes. The patients were divided into 3 groups randomly selected: group A received the infusion for 2 hours, group B for 4 hours and group C for 6 hours. Haematocrit (HCT), whole blood viscosity (VI-VB), blood elasticity (EL-VB) and plasma viscosity (VI-PL) were determined before onset of infusion, after 6 and 18 hours subsequently. The values obtained were compared with the onset results. In all groups and parameters after 6 hours there was a significant decrease. After 18 hours group A showed a significant higher value of HCT and increasing trends for VI-VB and EL-VB. In group B after 18 hours a significant decrease of VI-VB could be observed. In group C all values remained significantly below the onset. The results show, that one important haemorheological argument for an effective form of haemodilution should also be a long application time. This might be one of the reasons, why in some studies with hypervolemic haemodilution no positive results could be obtained.


Implication of the polyamines in the neurotoxic effects of N-methyl-D-aspartate.

N-Methyl-D-aspartate (NMDA) receptor activation selectively releases the polyamines spermine and spermidine from the rat striatum in vivo. The intrastriatal injection of spermine or spermidine is neurotoxic, but this toxicity is not blocked by MK-801 and unlikely to be mediated via the NMDA receptor. The neurotoxic effects of intrastriatally injected NMDA can, however, be reduced by polyamine synthesis inhibition with difluoromethylornithine. Alterations in polyamine metabolism in the ischaemic brain, although perhaps induced by NMDA receptor activation, may contribute to ischaemic cell loss via NMDA-independent mechanisms, possibly related to the diverse effects of polyamines on calcium homoeostasis and channel function.


Metabolic derangement in viable periinfarct tissue in the course of acute ischaemic infarction: a multitracer positron emission tomography (PET) study.

We used a multitracer positron emission tomography (PET) approach to assess metabolic changes in infarcted and periinfarct tissue in acute ischaemic stroke. 16 patients were studied within 6-48 hours (mean, 23 h) after onset of symptoms from a first hemispheric stroke and again 13-25 days later (mean, 15.6 days). Regional cerebral metabolic rates of oxygen (CMRO2) and glucose (CMRGlc), blood flow (CBF) and blood volume (CBV) were measured and oxygen extraction (OEF) as well as glucose extraction (GEF) and microvascular transit time were calculated. PET images were three-dimensionally aligned using serial CT or MRI scans. Regions of interest on the side of the infarction were individually compared to contralateral mirror regions. In the infarction core CBF, CMRO2 and CMRGlc were significantly lower than on the contralateral side and did not change during time. In the periinfarct regions there was a decreased CMRO2 with progressive deterioration over time while CBF slightly increased. Only in a few ischaemic regions with initially increased OEF oxygen metabolism was preserved during the course of time.


Production of transient ischaemic events by platelet emboli in baboons.

To investigate the pathophysiological process of transient ischaemic events in a clinically relevant model, we produced transient focal cerebral ischaemia in five baboons using endogenously generated platelet microemboli. Thrombogenic segments of Dacron vascular graft were incorporated as unilateral carotid arterio-arterial shunts to produce endogenous platelet microemboli. The embolized microparticles were quantified by isotopic imaging using 111In-platelets and by transcranial Doppler ultrasonography. Platelet microemboli accumulated rapidly in the shunted carotid territory and reached a maximum value of 3.2 +/- 0.8 x 10(9) in the embolized hemisphere 20 min after initiating blood flow through the graft segment. Sixty min after removing the grafts 111In-platelets were largely cleared from hemispheric vasculature. Recovered animals exhibited mild contralateral hemiparesis which disappeared completely within 24 h. We conclude that endogenously generated platelet microemboli accumulate transiently in the dependent cerebral circulation and produce corresponding transient focal neurological dysfunction. This model may be useful in the evaluation of new therapeutic strategies in acute stroke.


Molecular biological studies in atherothrombotic brain infarction.

Strokes due to atherosclerosis are the most prominent neurological disease affecting adults, and efforts to reduce stroke occurrence, in addition to stroke-risk reduction, will require insights into molecular mechanisms. Our studies showing abnormal metabolism of low and high density lipoproteins (LDL and HDL) in vivo and of RFLP in apoprotein AI, the major protein of HDL, in stroke-prone subjects suggest that greater exploration of fundamental mechanisms of atherothrombotic brain infarction (ABI) should yield preventative strategies, the ultimate treatment for strokes.


Quantitative middle cerebral artery flow in normal and vasospastic arteries.

To determine the degree of MCA vasospasm necessary to exceed the ischaemic threshold of blood flow reduction to less than 1/3 normal flow, we developed a computer model of blood flow in the middle cerebral artery distribution. When solved for a 3 mm trunk diameter, it showed a normal flow of 179 ml/min. It was necessary to decrease trunk diameter by 75%, or branch diameter by 50%, or increase peripheral resistance by a factor of 3, in order to decrease blood flow to less than 1/3 normal.


Effect of circulating pattern and complicating factors on outcome for ruptured anterior communicating artery aneurysms.

We reviewed outcome for ruptured anterior communicating artery (ACoA) aneurysm in 40 patients and attempted to establish its relationships with circulating pattern and complicating factors. Circulation Type-1 and Type-2 were associated with a better outcome than Type-3 and Type-4. Apart from arterial hypertension and cerebral infarction, all the complicating factors, i.e., vasospasm, brain oedema, intraparenchymal and/or intraventricular haemorrhage and hydrocephalus were related with an increased risk for poor outcome, but the broad outcome was more depended on circulating pattern for anterior cerebral territories.


Stroke and dolichoectatic intracranial arteries.

During a 6-year-period, in 45 patients the diagnosis of dolichoectatic intracranial arteries was established. Dolichoectasia of the vertebrobasilar system was the most frequent finding (n = 39). Twenty-two patients presented with brain stem ischaemia, and 10 patients had ischaemic hemispheric events. Six patients had symptoms due to compression of cranial nerves. Hydrocephalus was observed once. Peak and mean flow velocities in 39 patients with dolichoectatic basilar arteries as revealed by transcranial Doppler ultrasound were significantly reduced (p less than 0.00001) when compared with an age-adjusted control group of 20 patients without evidence of vertebrobasilar dolichoectasia on angiogram. Non-invasive MR-angiography offered an excellent imaging of the vascular abnormality. The combined use of CT, TCD, MRI and MR-angiography allows reliable non-invasive diagnosis of dolichoectatic intracranial arteries. This condition seems to play an underestimated role in stroke patients, in particular with respect to the vertebrobasilar circulation.


Supergiant anterior circulation aneurysms.

Six cases of very large anterior circulation intracranial aneurysms are presented. Aneurysms of 53-84 mm in three female and two male adults and a 40 mm lesion in a seven week infant were successfully excised. Three patients tolerated trial intraluminal balloon occlusion preoperatively and underwent subsequent parent artery ligation and aneurysmectomy with gratifying outcome. Three patients failed to tolerate trial occlusion and underwent prophylactic saphenous vein bypass grafts from the common carotid artery to the middle cerebral (MCA) prior to aneurysmectomy. In two of these (a 72 mm MCA and a 84 mm petrous carotid aneurysm), severe brain swelling after successful bypass procedures necessitated emergency craniotomy for aneurysmectomy and decompression. One of these never recovered and died one month later. In both cases in which malignant brain swelling followed bypass, preoperative CT and MR revealed significant hemispheric oedema and shift. Both patients had presented with signs of increased intracranial pressure and global mentational difficulties. Supergiant intracranial aneurysms pose major therapeutic risks, alternative therapeutic avenues must be addressed.


Haemodynamic changes following carotid occlusion: MRI angiography and transcranial Doppler patterns.

To see the signal changes in MR angiography (MRA) when occlusions or severe stenoses of carotid arteries occur and to relate these data with the velocity values provided by transcranial Doppler sonography (TCD), 20 patients showing symptomatic or asymptomatic unilateral carotid obstructions underwent both MRA and TCD after digital angiography investigation. No MRA signal was recorded immediately downstream from the carotid occlusion. Low flow velocity values in the carotid siphon and middle cerebral artery (MCA) ipsilateral to the carotid obstruction were associated with altered MRA signals corresponding to the same vessels. Turbulence phenomena induced by reversed flow in the anterior cerebral artery induced MRA signal impairments. In carotid occlusions, there may be a relationship between the MRA patterns and the flow velocity variations detected by TCD, but the two approaches have to be applied together since they provide complementary information.


Correlation of MRI and CT data with outcome of cerebral revascularization after stroke.

Sixteen patients with the occlusion of the internal carotid artery (ICA) underwent extra-intracranial bypass surgery. All patients had stroke in evolution or completed stroke with mild or moderate (n = 9) or severe (n = 7) neurological deficits. In each case, the clinical course, magnetic resonance imaging (MRI), computed tomography (CT) and angiographic (AG) findings were evaluated. Patients were followed up from 9 months to 2.5 years postoperatively. MRI was much more sensitive than CT for appreciating the ischaemic tissue. The infarct volume determined by MRI had greater extent than previously detected by CT. If the difference of the infarct volume, detected by MRI and CT was more than 30% the patients appeared to have benefited from bypass surgery as demonstrated clinically as well as with postoperative MRI and AG studies. Patients with lesser difference showed insignificant or no postoperative improvement.


Correlation between serum lipids and stroke in an Israeli population.

The role of blood lipids as a risk factor for cerebrovascular disease remains uncertain. In the present prospective study, 202 patients admitted with stroke to a community hospital in Jerusalem were evaluated. All patients had a full clinical and neurological evaluation, and a risk factor analysis. The study protocol included routine blood evaluation, fasting blood lipid analysis, brain imaging, 2D echocardiography and carotid Doppler ultrasonography. Stroke risk factors were correlated to stroke types as defined by the modified NINCDS Stroke Data Bank Criteria. Lacunar and atherosclerotic ischaemic infarctions were the most frequent type of stroke in both sexes. Lipid values were in general lower in males than in females. Comparison of stroke patients to age and sex matched controls disclosed lower LDL-C values in male and female patients (p less than 0.001), and lower cholesterol levels in women with strokes than in control subjects (p less than 0.001). Our study corroborates previously reported risk factors for stroke: hypertension (major risk factor in both sexes), smoking (more prevalent in males) and diabetes (more frequent in females).


Flow separation in the carotid bulb: prognostic significance.

It has been previously shown that boundary layer or flow separation occurring in the carotid bulb and detected by duplex scanning denotes minimal or no carotid atherosclerotic disease as demonstrated by angiography and reliably predicts aetiology other than carotid artery disease in symptomatic patients. To evaluate outcome at long-term follow-up we prospectively studied 94 patients (48 males, 46 females) who demonstrated bilateral flow separation. Mean age was 61.2 years (27 to 86 years). Mean follow-up was 57 months (5 to 113 months). There was one death during follow-up at 69 months. It was stroke related. Using age and sex specific death rates for the general population 14.3 deaths would be expected for the same average period. By life table analysis, survival was 98.7% at five years compared to a general population expected 5 year survival of 85.9%. There were no strokes at 5 years of follow-up. (Age and sex specific stroke-free survival for Rochester, MN 1970-1974 is 98% at 5 years). TIA-free survival was 99% at one year (n = 87) and 96% at five years (n = 46). It is concluded that the presence of boundary layer separation in the carotid bulb not only indicates absent or minimal atherosclerotic disease, but is predictive of a favourable long-term outcome with respect to mortality and neurological events.


Frequency of transient ischaemic attacks in strokes: place for a preventive treatment.

Transient ischaemic attack (TIA) represents a neurological deficit during less than 24 hours, without any abnormality on CT scan. This symptom may have 2 risks: it may give place to a severe stroke, and it is not always linked to an ischaemic mechanism. This work rests on a population-based registry existing in Dijon since 1985 with a specific and exhaustive registration. CT scan allows the mechanisms of stroke to be identified: cortical infarct, lacunar infarct, cerebral haemorrhage, and TIA. TIA represent 15% of stroke. Survival rate of 80% is better than other strokes. A TIA may appear before a cerebral infarct in 48% of the cases, a lacunar infarct in 18% of the cases, another TIA in 28% of the cases, and a haematoma in 8% of the cases. Therefore TIA is an important symptom appearing before severe stroke, that may let place to a preventative action.


Haemorheological factors in the pathophysiology of acute stroke.

Blood viscosity studies were carried out in fourteen patients with acute stroke, eight with cerebral infarction, six with cerebral haemorrhage and in thirteen controls. We observed a statistically significant higher values of plasma, red cell and whole viscosity in patients with acute stroke than in normal controls. Plasma fibrinogen levels were statistically higher (p less than 0.01) in patients than in normal controls. The platelet aggregation was increased in two young adults with acute stroke. The results suggest that the haemorheological factors play an important role in the pathophysiology of stroke patients.


Effect of the risk factors for stroke on survival.

In a case-controlled study into the risk factors for admission to hospital with stroke, 400 subjects and 400 age and sex-matched controls were recruited. All bar two subjects were followed until death or 6 months. Previous stroke and regular snoring (p = 0.0013 and p less than 0.0001 respectively) were the only two risk factors adversely to effect mortality. Transient ischaemic attack, ischaemic heart disease, hypertension, atrial fibrillation, diabetes mellitus did not significantly effect prognosis. An apparent beneficial effect of drinking alcohol and smoking became insignificant when the confounding influence of age was taken into account.


Watershed cerebral infarcts: retrospective study of 24 cases.

Twenty-four patients presenting an acute stroke with watershed cerebral infarct on CT scan or MRI were included in this retrospective study. Age was 63 +/- 14 years (mean +/- SD), and sex ratio was 2 men for 1 woman. Main clinical features were: in anterior location, lower limb weakness and frontal syndrome with transcortical motor aphasia in left lesions or spatial dyscalculia in right ones; in posterior location, brachiofacial weakness with constant quadranopsia and hypoesthesia, and Gerstmann syndrome in left lesion. There was no distinctive feature for subcortical and multiple infarcts. In bilateral infarcts, there were one pseudobulbar syndrome, and 2 pseudo brainstem syndromes with neuropsychological signs. Aetiologies were severe carotid artery disease in 14 cases, severe cardiopathy in 6, isolated cerebral angiitis in 1, essential thrombocythemia in 1, protein C deficiency with sickle cell disease in 1, and cholesterol emboli in 1 anatomical case. CBF performed in carotid artery occlusions or tight stenoses showed evidence of haemodynamic changes. Microembolic process can be proposed in the case with cholesterol emboli. Preventive treatment is discussed.


Participation of arginine vasopressin-mediated and adrenergic system-mediated mechanisms in the hypertension induced by intracerebroventricular administration of NMDA in freely moving rats.

Effects of intracerebroventricular (third ventricle) injection of N-methyl-D-aspartate (NMDA) on arterial blood pressure, on heart rate, on arginine vasopressin (AVP) and levels of catecholamines in plasma and on the behaviour of normotensive freely-moving rats have been evaluated. N-Methyl-D-aspartate significantly (P less than 0.01) increased arterial blood pressure and levels of catecholamines and AVP in plasma. With 0.1-1.0 micrograms/rat all animals presented psychomotor agitation, stereotyped movements, hyperexcitability, exophthalmus, dyspnoea, jumping, rearing and teething. The selective antagonist for NMDA receptors, 2-APV injected in the third ventricle, significantly (P less than 0.01) antagonized the hypertension, the increase in levels of catecholamines and AVP in plasma and behavioural effects. An antagonist of alpha 1 adrenergic receptors, prazosin (i.v.), an agonist of alpha 2 adrenergic receptors, clonidine (i.c.v.) and a relatively selective antagonist of V1 subtype of receptor of AVP, CGP 25838 (i.c.v. and i.v.), 15 min before NMDA, significantly (P less than 0.01) decreased the effects induced by the injections of NMDA. On the contrary, an antagonist of opiate receptors, naloxone (i.v.), 15 min before NMDA, significantly (P less than 0.01) increased the NMDA-induced modifications. Pretreatment with the antagonists at these doses, did not significantly modify the basal values of arterial blood pressure and behaviour. Only 2-APV sometimes induced ataxia, lasting about 5 min. This study points out an increase in the central sympathetic efferent activity and in release of AVP involved in the NMDA-induced cardiovascular and behavioural effects.


Chrononephrotoxicity in rat of a vancomycin and gentamicin combination.

The effect of time of administration on excretion of two brush border enzymes--alanine aminopeptidase (AAP) and gamma-glutamyl transferase (gamma GT), and a lysosomal enzyme, N-acetyl-beta-D-glucosaminidase (NAG) with a single high dose of vancomycin, gentamicin or a combination of vancomycin and gentamicin was studied in male Wistar rats and compared with elimination of a control group. The rats received vancomycin intraperitoneally (200 mg.kg-1), gentamicin intramuscularly (100 mg.kg-1) or the combination of the drugs by the same route. A control group received isotonic NaCl solution. The four groups of animals received a single injection at 8 a.m., 2 p.m., 8 p.m., and 2 a.m. and urine excretion values for AAP, gamma GT and NAG were determined 24 hr later. The results show that the nephrotoxicity of gentamicin + vancomycin is greater than that observed with gentamicin, which again is greater than that observed with vancomycin. Furthermore, circadian variations in renal toxicity were observed, the least occurring at 8 a.m.


A broad-spectrum cytolytic toxin from Bacillus thuringiensis var. kyushuensis.

Bacillus thuringiensis (Bt) var. kyushuensis synthesizes a mosquitocidal crystalline inclusion containing several proteins ranging from 140 to 14 kDa. We have identified a 25 kDa protein protoxin in this inclusion which is not cytolytic, but when activated proteolytically to 23-22 kDa products is cytolytic to mosquito, lepidopteran and mammalian cells, can release entrapped glucose from liposomes and forms cation-selective channels in a planar lipid bilayer. This broad-spectrum cytolytic toxin is related antigenically to the 23 kDa toxin from Bt var. darmstadiensis strain 73-E10-2, but not to the 25 kDa CytA toxin of Bt var. israelensis. The cytolytic activity of these Bt var. kyushuensis toxins, like that of the latter two toxins, can be neutralized by incubation with liposomes containing phospholipids.


Detection of prodynorphin end products in lizard, turtle, and alligator brain extracts.

Heterologous radioimmunoassays (RIAs) for the mammalian prodynorphin end products, alpha-neo-endorphin, dynorphin A(1-17), dynorphin A(1-8), and dynorphin B(1-13) were used to screen brain extracts obtained from representatives of the major surviving orders of reptiles: Chelonia (Pseudemys scripta), Squamata (Anolis carolinensis), and Crocodylia (Alligator mississippiensis). Methanol/acid extracts of whole brains obtained from each species were separately fractionated by gel filtration chromatography and reversed-phase HPLC. In all three species, an immunoreactive form of alpha-neo-endorphin was detected with the same retention time as synthetic mammalian alpha-neo-endorphin following reversed-phase HPLC analysis. In all three species, reversed-phase HPLC analysis revealed a novel form of dynorphin B(1-13)-related immunoreactivity. With the available immunological probes, dynorphin A products were only detected in the Anolis brain extracts. Both dynorphin A(1-17) and dynorphin A(1-8) were detected in this species.


The neurons in layer 1 of cat visual cortex.

We have examined the morphology of neurons in layer 1 by injecting them intracellularly with lucifer yellow in lightly fixed brain slices (250 microns thick) taken from the medial bank of area 17 in adult cats. Of 22 neurons with well-filled dendrites, 16 had smooth dendrites, two had sparsely spiny dendrites (less than 200 spines) and, unexpectedly, four had spiny dendrites typical of pyramidal cells. The axon was generally not well filled. Computer reconstructions showed that parts of the dendritic tree had been lost in the sectioning. Nevertheless, measurements of the length of intact dendrites suggested an average diameter of the dendritic tree of 220 microns. The density of the neurons was such that the dendritic trees of about six neurons cover each point in layer 1. Thus, despite the very low density of neurons that characterizes layer 1, there are more than sufficient neurons to sample from the entire representation of the visual field in area 17.


Oral administration of Tyr-MIF-1 stimulates gastric emptying and gastrointestinal motility in rodents.

The effects of orally administered Tyr-MIF-1, an agonist of an endogenous antiopiate system, were examined on gastric emptying in mice and gastrointestinal myoelectric activity in rats. Tyr-MIF-1 (5 mg/kg in mice, 20 mg/kg in rats) accelerated gastric emptying of a methylcellulose test meal, increased the frequency of antral spike bursts, and disrupted intestinal migrating myoelectric complexes. These effects were reproduced by a subcutaneous administration of Tyr-MIF-1 at the same dosage. They were blocked by naloxone (1 mg/kg) but not by the kappa receptor subtype antagonist MR 2266 (1 mg/kg). The GABAA antagonist bicuculline (0.5 mg/kg), but not the GABAB antagonist 2-hydroxysaclofen (4 mg/kg), also antagonized the effects of Tyr-MIF-1. These data demonstrate that oral Tyr-MIF-1 stimulates gastric emptying and gastrointestinal motility through a systemic or central action that involves opioid and GABA systems.


A novel cholinergic receptor mediates inhibition of chick cochlear hair cells.

The central nervous system provides feedback regulation at several points within the peripheral auditory apparatus. One component of that feedback is inhibition of cochlear hair cells by release of acetylcholine (ACh) from efferent brainstem neurons. The mechanism of hair cell inhibition, and the character of the presumed cholinergic receptor, however, have eluded understanding. Both nicotinic and muscarinic, as well as some non-cholinergic ligands can affect the efferent action. We have made whole-cell, tight-seal recordings from short (outer) hair cells isolated from the chick's cochlea. These are the principal targets of cochlear efferents in birds. ACh hyperpolarizes short hair cells by opening a cation channel through which Ca2+ enters the cell and subsequently activates Ca(2+)-dependent K+ current (Fuchs & Murrow 1991, 1992). Both curare and atropine are effective-antagonists of cholinergic inhibition at 3 microM, whereas trimethaphan camsylate and strychnine block at 1 microM. The normally irreversible nicotinic antagonist, alpha-bungarotoxin, reversibly blocked the hair cell response, as did kappa-bungarotoxin. The half-blocking concentration for alpha-bungarotoxin was 26 nM. It is proposed that the hair cell AChR is a ligand-gated cation channel related to the nicotinic receptor of nerve and muscle.


Costs to host defence and the persistence of parasitic cuckoos.

Raising genetically unrelated young is maladaptive, yet brood parasitism is widespread in birds. In several systems, hosts can evolve near-perfect defences against the parasite (discrimination and rejection of unlike eggs), making it difficult to understand how the parasite continues to exist. This study demonstrates costs to host defences (e.g. rejection of one's own eggs) such that once the parasite goes extinct on a particular host species, defence mechanisms are selectively disadvantageous. The consequent loss of host defences, and potential for re-exploitation of the host by the parasite, can explain the continued persistence of avian brood parasites. The results provide one general explanation for coexistence of parasites and their hosts.


On the existence of 'fast' and 'slow' directionally sensitive motion detector neurons in insects.

In a fly, butterfly, locust and dragonfly we examined the responses of a variety of directional motion-sensitive neurons which run from the brain down the ventral cord. The stimulus was a sinusoidally modulated moving pattern of regular stripes presented at a range of velocities in random order for either 0.1 s or 2.0 s. The response was measured as the total number of spikes to each stimulus. The neurons fall into two groups, 'fast' and 'slow'. The responses of the fast type rise progressively to a peak contrast frequency at 15-20 Hz for all four insects, and decline at higher contrast frequencies. The responses of slow neurons rise rapidly to a peak at 1-10 Hz and then decline more slowly across the range where the fast neurons are at their peak. The existence of two groups of neurons with overlapping response ranges to different velocities of the same pattern, presented in exactly the same way, provides the insect with a means of measuring angular velocity irrespective of contrast, spatial frequency or intensity. As an input mechanism it is proposed that there are two types of unit motion detector, fast and slow, the latter being the main input to the optomotor system. It is also argued that even these inputs are not sufficient to provide a mechanism for the whole repertoire of normal insect vision.


Intracellular symbionts and the evolution of uniparental cytoplasmic inheritance.

Uniparental inheritance of cytoplasmic elements is widespread among eukaryotic organisms and is achieved by a diverse range of mechanisms. This paper shows that the cytoplasmic genetic system would be expected to evolve towards uniparental inheritance, given the existence of deleterious symbionts capable of invading the host cytoplasm together with nuclear genes that lead to the elimination of cytoplasmic elements from one of the gamete types. The reason for this is that, under biparental inheritance, foreign symbionts with strong deleterious effects are able to spread through host populations. A nuclear modifier gene which leads to the loss of cytoplasmic elements from one gamete type gains a net advantage as a symbiont spreads, because the modifier sometimes gives rise to a symbiont-free zygote. Insofar as small gametes reduce the rate of symbiont transmission to the zygote, modifier genes causing small gamete size would tend to accumulate, so that cytoplasmic inheritance would become associated with maternal rather than paternal gametes. Once uniparental inheritance predominates in the host population, the population is protected from invasions by a large class of harmful symbionts, but at the same time those symbionts that benefit their hosts are still able to increase in frequency.