Success of kidney transplantation in oxalosis is unrelated to residual hepatic enzyme activity. We evaluated hepatic alanine glyoxylate aminotransferase (AGT) activity in percutaneous hepatic biopsy material obtained from four children with long-term renal allograft function following transplantation for primary hyperoxaluria type 1 (PH 1). The study was performed to determine whether these successes had occurred because relatively high residual levels of AGT activity had introduced a selection bias. The children ranged from seven months to eight years at transplant and are currently well 7 to 11 years later, with no oxalate deposition on repeated allograft biopsies and creatinine clearances of 80 to 128 ml/min/1.73 m2. AGT activity ranged from 0 to 13.8%, and in two of three patients with detectable levels the AGT was in mitochondria rather than peroxisomes. These results indicate that long-term renal allograft success can occur in spite of severe AGT deficiency. Thus, the therapeutic choice of kidney alone versus combined kidney-liver transplant cannot currently be made by measuring residual hepatic AGT in PH 1. Kidney transplant alone remains a reasonable initial therapeutic alternative for patients with recent onset of renal insufficiency due to PH 1.


Convection does not govern plasma to dialysate transport of protein. The dependence of protein clearance on molecular size during peritoneal dialysis can be explained by assuming that either convection or diffusion is the major mechanism governing plasma to dialysate transport of protein. If convection is the predominant transport mechanism, then plasma-to-dialysate transport rates for protein should not decrease when the protein concentration in the instilled dialysis solution is increased. In the present study, plasma-to-dialysate transport rates for fluorescein-labeled protein tracers, alpha-lactalbumin and immunoglobulin G (IgG), were determined during a six hour isotonic exchange (25 ml/kg) in New Zealand White rabbits. The protein tracers were continuously infused into the bloodstream to keep plasma concentrations relatively constant, and transperitoneal transport rates were determined either with or without tracer protein added to the instilled dialysis solution. Plasma-to-dialysate transport rates were greater for alpha-lactalbumin than for IgG as expected based on the molecular size of these proteins. Transport rates for both alpha-lactalbumin and IgG decreased when tracer protein was added to the instilled dialysis solution. The present observations do not support convection as the major mechanism governing plasma to dialysate transport of protein during peritoneal dialysis.


In vitro production of interleukin-1 receptor antagonist in chronic renal failure, CAPD and HD. Dialysis-related symptoms are believed to be mediated, at least in part, by monocyte/macrophage-derived pro-inflammatory cytokines including interleukin-1 (IL-1) and tumor necrosis factor (TNF). Measuring the production of interleukin-1 receptor antagonist (IL-Ra), a naturally occurring inhibitor of IL-1, opens avenues to study the balance between these two cytokines in patients. We studied the cell content and production of IL-1 beta and IL-Ra by unstimulated and endotoxin- or IgG-stimulated peripheral blood mononuclear cells (PBMC) in undialyzed patients with chronic renal failure (CRF), patients on continuous ambulatory peritoneal dialysis (CAPD) and patients on chronic hemodialysis with reuse cuprophan membranes (HD), and compared them to healthy controls. IL-1 beta and IL-Ra were measured by specific radioimmunoassay. IL-1 beta was undetectable in freshly harvested PBMC from healthy controls, CRF, CAPD or HD. In contrast, the content of IL-Ra in HD patients (2828 +/- 466 pg/ml) was significantly higher than that in healthy controls (643 +/- 53 pg/ml, P < 0.01), CRF (1097 +/- 320 pg/ml, P < 0.01) or CAPD (1398 +/- 390 pg/ml, P < 0.05). In endotoxin-stimulated PBMC, IL-1 beta production by HD patients (9375 +/- 1687 pg/ml) was not significantly different from healthy controls (8429 +/- 1621 pg/ml). However, endotoxin-stimulated IL-Ra production by HD patients (32,350 +/- 8276 pg/ml) was greater than that from healthy controls (11,284 +/- 1250 pg/ml, P < 0.001), CRF (12,263 +/- 2680 pg/ml, P < 0.01) or CAPD patients (11,822 +/- 1797 pg/ml, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)


Nature and rate of vascular refilling during hemodialysis and ultrafiltration. The change of blood volume, of blood and plasma density (rho b, rho p) following a short ultrafiltration pulse (duration: 20 min; mean rate -35 ml/min) within the first hour of hemodialysis was analyzed in 13 hemodynamically stable patients (30 single measurements). Protein concentration of refilling volume (7 g/liter) was calculated from its density (1009.25 +/- 3.7 kg/m3, at 20 degrees C) and from the linear relationship between plasma density and protein concentration (cp) of uremic plasma samples (rho p = 1007.46 + 0.2422 x cp). The filtration coefficient (Lp,calc) determined from a relation derived from Starling's hypothesis was 5.6 +/- 1.4 ml/(min.mm Hg.50 kg lean body mass); N = 13, mean +/- SD, minimum 3.2, maximum 8.0. A model describing the dynamics of blood and plasma volume was developed. It was fit to on-line measurements of relative blood volume changes by variation of the filtration coefficient and of initial blood volume (Lp,fit, Vb,fit). The linear regression between Vb,fit and blood volume determined from anthropometry (Vb,calc) was highly significant (r = 0.79, N = 30, P < 0.001). Compared to Vb,calc, Vb,fit was typically increased by 21 +/- 11%, reflecting a fluid overload at the beginning of the treatment. Lp,fit was not different from Lp,calc. Lp,fit significantly increased with blood volume excess. Due to the small but definite protein content of refilling volume, the model accounts for increased blood volume recovery and occasional overshoot of blood and plasma volumes following ultrafiltration.


Kinetics of 125I-beta 2-microglobulin turnover in dialyzed patients. The kinetics of beta 2-microglobulin (beta 2m) were studied in 17 anephric or functionally anephric hemodialyzed patients and five healthy subjects as controls. Highly purified beta 2m was radiolabeled with 125I and infused into patients. The radioactivity in plasma and dialysis fluids was measured during a week including two or three dialysis sessions. Patients were classified in four groups according to treatment: hemodialysis on Cuprophan (N = 5) or on AN69 membranes (N = 5), hemofiltration (N = 4) and CAPD (N = 3). Plasma activity was fitted to a three compartment model. In controls almost 100% of the radioactivity was recovered in urine within 96 hours and there was no extrarenal catabolism. In patients the fractional catabolic rate ranged from 0.0008 to 0.0022 min-1 versus 0.026 to 0.047 min-1 in controls. The synthetic rate was within the range of values from controls in 10 patients but higher in the seven others. It was correlated with plasma beta 2m concentration. Kinetic data indicate a retention of intact beta 2m. The original model was therefore modified with an additional compartment representing beta 2m captation. The amount of capted beta 2m was more elevated in hemodialyzed patients than in patients treated by hemofiltration or CAPD, in whom it could reach 5 mg/kg/day. Hemofiltration or CAPD may eliminate about 30 to 100% of beta 2m produced and therefore contribute to the low captation amount of these patients, as compared with that of patients treated by hemodialysis.


Renal extraglomerular vascular immune deposits in IgA glomerulonephritis. Kidney biopsies of 425 patients with IgA glomerulonephritis were studied to reveal the incidence, composition and possible clinical significance of extraglomerular vascular immune deposits. IgA deposits were detected in 20 cases, IgM in 28 (in 5 together with IgA), C3 in 317 and no vascular deposits in 60 cases. C3 and IgA deposits were granular, resembling mesangial deposits, while IgM deposits were lumpy, similar to IgM deposits in sclerotic and hyalinized glomeruli. The incidence of vascular lesions in patients with IgA (30%) and C3 deposits (24%) was not significantly higher as compared to those without vascular deposits (20%), but was significantly higher in patients with IgM deposits (68%, P < 0.00004). Only the presence of vascular IgM deposits correlated significantly with severe glomerulosclerosis, arterial hypertension and elevated serum creatinine levels (all P < 0.001). We conclude that neither C3 nor IgA deposits, in spite of their suggested immune complex nature, contribute significantly to the development of vascular lesions. Lumpy IgM deposits, probably the result of insudation of plasma proteins into the blood vessel walls, were associated with advanced vascular lesions and glomerulosclerosis and are probably a part of non-immune mediated progression of IgA glomerulonephritis.


Vascular permeability factor mRNA and protein expression in human kidney. Vascular permeability factor (VPF), also known as vascular endothelial growth factor (VEGF), is a potent microvascular permeability-enhancing mediator as well as a selective mitogen for vascular endothelium. In this study, in situ hybridization and immunohistochemistry co-localized VPF mRNA and protein to glomerular visceral epithelial cells in human kidneys. Northern analysis confirmed the presence of VPF mRNA of expected size. The finding of VPF in renal glomerular epithelium identifies a potent mediator of permeability and endothelial proliferation whose role in renal physiology and pathology requires investigation.


Glomerular matrix accumulation is linked to inhibition of the plasmin protease system. TGF-beta plays a pivotal role in the pathological accumulation of extracellular matrix in experimental glomerulonephritis. Increased TGF-beta expression leads to increased synthesis and deposition of extracellular matrix components while administration of anti-serum to TGF-beta suppresses the major manifestations of the disease. We hypothesized that TGF-beta might also enhance matrix accumulation by decreasing matrix turnover via effects on protease/protease inhibitor balance. Plasmin is a potent protease capable of degrading a variety of matrix molecules. Plasmin generation from plasminogen is regulated by plasminogen activator(s) (PA) and plasminogen activator inhibitor(s) (PAI). In this study PA activity was markedly reduced and PAI-1 synthesis dramatically increased when TGF-beta was added to normal glomeruli. Diseased glomeruli also showed decreased PA activity, increased PAI-1 synthesis and increased PAI-1 deposition into matrix. Administration of anti-TGF-beta serum to glomerulonephritic rats blocked the expected increase in glomerular PAI-1 deposition. Thus changes in the PA/PAI balance favoring accumulation of matrix are induced by TGF-beta in normal glomeruli and are present in nephritic glomeruli when endogenous TGF-beta production is high. Our findings implicate the plasmin protease system in tissue repair following acute glomerular injury and suggest another mechanism by which TGF-beta enhances the matrix accumulation characteristic of many glomerular diseases.


[Choice of the surgical method in gastric cysts]. Operations for gastric cysts were carried out on 8 patients (4 males and 4 females whose ages ranged from 33 to 65 years). Three patients had true cysts, 2 had inflammatory cysts; there were one case of neoplastic, one of retention and one of hydatid cyst. Organ-preserving operative interventions (enucleation, cystectomy, endoscopic cyst gastrostomy, antrum resection) were performed on 7 patients, one patient with an erroneous diagnosis of gastric carcinoma was subjected to subtotal resection of the stomach. There were neither complications nor fatal outcomes. It is claimed that patients with gastric cysts should be treated by surgery. An organ-preserving operation should be the method of choice.


[Morphofunctional characteristics of the gastric neuroregulatory apparatus after cryogenic effects on the vagus nerves]. Nine groups of experiments were conducted on 120 rats and 55 dogs to study the morphological changes and the density of cholinergic nerve fibres in the intramural nerve apparatus of the stomach after cooling of the vagus nerves at various temperatures and time regimens of the exposure (-35-45 degrees, -70-80 degrees for 2-3 sec., 15 sec in one, two, and three exposures). The completeness of vagotomy was determined by the method of parietal pH measurement and modelling of stress-induced ulcers. It was established that depending on the thickness of the nerves and the regimen of the exposure to cooling, one can achieve total vagotomy with destructive changes in the nerve apparatus, incomplete vagotomy and transient inhibition-blockade of the acid-regulating function of vagus nerves with maintenance of the morphological and histochemical characteristics of intramural plexuses.


[Endoscopic removal of isolated gastrinoma of the duodenum after Billroth II gastric resection]. Duodenal carcinoma is a rare disease and is encountered in no more than 10% of cases of the Zollinger-Ellison syndrome. The article discusses a rare case in which an isolated duodenal gastrinoma was removed endoscopically with subsequent recovery from the Zollinger-Ellison syndrome. Study of the serum gastrin concentration with provocative tests allowed the Zollinger-Ellison syndrome to be diagnosed and the radicality of duodenal gastrinoma removal to be controlled. Retrograde duodenoscopy conducted after resection of the gastric stump by the Billroth II method localized the source of hypergastrinemia and made possible radical removal of the duodenal gastrinoma, which was confirmed by normalization of the blood serum gastrin concentration. The work includes a brief literature reference on the subject.


[Tactics in gastrointestinal hemorrhage under conditions of medical aviation]. Doctors of the medical aviation service were consulted in 774 cases of gastrointestinal bleeding of various genesis in 1985-1989. Chronic gastroduodenal ulcer (peptic ulcer of the anastomosis among others) was the source of the bleeding in 473 (64.88%) patients. In the first period of observation (1985-1986) active surgical tactics was applied in 103 patients with chronic bleeding ulcer. Fifty-one patients (49.5%) underwent operation, with a fatal outcome in 12 cases (23.5%). Active individualized tactics was accepted in the second period (1987-1989). In a group of 370 patients 185 (50%) were operated on, 20 with fatal outcomes (10.8%). Active surgical tactics was individualized by strict comparison of the amount of blood loss and the degree of activity of the bleeding. Clinico-endoscopic and laboratory interpretation of the degree of activity of the bleeding is described and the expediency of indicating this criterion along with the amount of blood loss in establishing the diagnosis in a patient with bleeding from the ulcer is pointed out.


[State of microcirculation channel in the area of laser "welded" anastomosis of the small intestine]. Experiments were conducted with CO2 and AIG laser on neodymium to study the condition of microcirculation and the degree of its disturbance in the wall of the small intestine in formation of a laser "welded" entero-enteral and termino-terminal anastomosis. The microcirculatory disorders and their extent were found to be directly dependent on the degree of the thermal effect and the width of the coagulation zone in the region of the suture. The results of the experiment confirmed that the suggested powers of the laser effect on the intestinal wall were optimal.


[A comparative study of nonsurgical methods in the treatment of hemorrhoids]. The authors conducted comparative appraisal of the results of treatment of hemorrhoids in 3 groups of patients at a higher surgical risk in 1989-1990. Group 1 consisted of 79 patients given the traditional nonoperative treatment. Group 2 was made up of 17 patients in whom the hemorrhoidal nodes were ligated by means of latex rings. Forty-three patients of group 3 were treated by the traditional nonoperative methods and, in addition, by infrared photocoagulation, 33 at in-patients and 10 at out-patient clinics. The follow-up periods range from 3 to 12 months. The study showed that nonoperative therapy produced a temporary effect, clinical manifestations of hemorrhoids recurred in 100% of patients. In group 2 59% of patients were cured, which is evidence of the pathogenetic substantiation of the method. The treatment, however, in this group was marked by a great number of complications of an inflammatory character. The best effect was produced among patients of group 3; 37 (86%) patients were cured. Thus, the results of comparative analysis of the efficacy of these methods of treatment in patients at a higher surgical risk showed the advantages of infrared photocoagulation over nonoperative treatment and ligation of hemorrhoids with latex rings. The method of infrared photocoagulation is technically simple, convenient, and can be applied both in in- and out-patient clinics.


[Classification of stomach ulcers and choice of the surgery method]. The article generalizes the findings of examination and experience in the surgical treatment of 404 patients with gastric ulcers. A classification of gastric ulcers is suggested: Type I, true gastric ulcers; Type II, combined gastric and duodenal ulcers; Type III, suprapyloric and pyloric ulcers; Type IV, multiple ulcers of the stomach; Type V, secondary gastric ulcers. On the basis of this classification the authors substantiate the wide use of modified resections of the stomach after Billroth I. Chronic disorders of duodenal patency was revealed in 10 (2.47%) of patients who underwent operation, compensated duodenal stasis was encountered in only one of them. Billroth I operation was performed on 357 (88.4%) patients and Billroth II on 47 (11.6%) patients. The postoperative mortality was 1.73%. The Billroth I operation produced excellent and good late-term results in 90.1% of patients with gastric ulcers.


[Prevention of incompetence of sutures of the colon in its injuries]. The authors analysed 242 clinical cases of open and closed injury to the colon and the results of experiments on 120 animals. Incompetence of the sutures of the colon was encountered in 12 (4.9%) patients: in 10 (5.2%) with punctured-incised injuries, in one (3.3%) with subcutaneous rupture, and in one (5.5%) with gunshot injury. Clinico-experimental studies allowed 2 groups of pathogenetic factors (predisposing and resolving) in the development of incompetence of colonic sutures to be distinguished. The pathogenetic approach forms the basis of the developed complex program of the prevention of incompetence of the sutures of the colon in its injuries. Introduction of the suggested program into clinical practice made it possible to reduce the incidence of incompetence of colonic sutures from 6.6 to 2.0%.


[Effects of intravascular laser irradiation of blood on erythrocyte stereo-ultrastructure in the treatment of generalized suppurative peritonitis]. The authors analysed the course and the results of examination of peripheral blood in dynamics and study of red cell stereo-ultrastructure in dynamics before and after sessions of intravascular laser irradiation of blood (ILIB) and treatment in 120 patients with peritonitis, in 60 of them ILIB was applied in the complex of intensive therapy (main group). The control group was made up of 60 patients. The studies showed a favorable curative effect of ILIB: the morphological characteristics of red cells and peripheral blood in patients with peritonitis improves. The laser irradiated blood evidently stimulates the bone marrow and the organs in which blood elements are stored as a result of which their ejection into circulation intensifies. The favorable effect of ILIB is also manifested by increase of the number of intermediate and reduction of the number of prehemolytic and degenerating forms of red cells in various stages of peritonitis, i.e. ILIB affects mainly the retransformation of stomatocytes into discocytes but produces no marked effect on echinocytic transformation.


[Endoprosthesis of rigid and extended cicatricial strictures of the esophagus]. The article describes treatment of 65 patients with postburn, extended, rigid cicatricial strictures of the esophagus by the method of temporary endoprosthetics. Most patients had an extended stricture. In 44 patients the diameter of the stenosed segment measured no more than 4 mm. Stage endoprosthesis of the esophagus was carried out in 32 patients. Devices by which intraoperative dilatation of the stricture can be achieved and its rigidity measures are shown, as well as designs of esophageal endoprostheses and an extractor of the endoprosthesis. The method suggested by the authors produced good results in 60 patients, esophagoplasty had to be undertaken in the remaining 5 patients. There were no fatal outcomes.


[Choice of the method of cardial correction during selective proximal vagotomy and gastric resection]. The author studied the condition of the esophagogastric junction in 376 patients with gastric and duodenal ulcer before and in the late-term periods after selective proximal vagotomy and distal resection of the stomach performed in combination with antireflux interventions on the cardia (fundoesophagorrhaphy, crurorrhaphy+fundoesophagophrenorrhaphy, fundoplication) or without such interventions. It is shown that reliable correction of the obturator mechanism of the cardia in selective proximal vagotomy may be achieved only by fundoplication. In gastric resection fundoplication is advisable in marked reflux esophagitis, distention of the hiatus esophageus of third degree, hernia of the hiatus esophageus, and cardiac ulcer. In all other patients with distal resection of the stomach crurorrhaphy+fundoesophagophrenorrhaphy is justified as a preventive measure.


[Mucociliary transport in patients with acute pneumonia]. Mucociliary transport (MCT) was investigated in 45 and 20 patients with acute focal and croupous pneumonia, respectively. MCT condition was assessed by its duration, adherence and surface tension of the sputum, water fractions. Early disease was characterized by mucociliary insufficiency as shown by longer M T duration, increased surface tension and adherence. Abnormal bronchial clearance resulted in reduced bronchial permeability. The above indices should be considered to administer early correction of the disorders.


[The mitral valve chordal system as a cause of innocuous heart murmur]. To specify the role of morphofunctional features of mitral chorda in forming innocent cardiac murmur (ICM), 107 and 20 young men with or without ICM, respectively, were examined clinically and instrumentally at rest, muscular load and hyperventilation. Echocardiography was recorded in one-dimentional, sectoral and Doppler regimens. Fluttering chorda (FC) of the mitral valve (MV) manifesting by hyperkinesia of usually fixed MV chorda, its early systolic dislocation into the left ventricular outflow tract was registered in 34.5% of ICM patients, 11.2% of them had echocardiographic evidence of the chordal shift in the systole into the above tract. In ICM-free subjects the phenomenon FC and the systolic chordal shift were absent (the difference was significant, p < 0.05). The FC phenomenon is attributed to local dysfunction of the papillary muscles and may produce distinct labile nonregurgitation systolic murmur.


[The compound "eric" in the treatment of bronchopulmonary diseases]. The drug erik was used in 32 patients with chronic bronchitis and acute bacterial pneumonia. Out of 132 strains assessed for sensitivity, 94 (68.6%) were sensitive to the above antibiotic, the rest demonstrated moderate sensitivity or drug resistance. The dose 0.5 g persisted in the blood for up to 12 hours allowing its use three times in 24 hours. The response was achieved in 32 patients (72.18%).


[Correction of bronchial hyperreactivity with Corinfar in patients with chronic renal insufficiency]. As shown in the provocative tests in eighteen 24-42 year old chronics with renal insufficiency, corinfar pretreatment (20 mg sublingually) can protect against acetylcholine-induced bronchial hyperreactivity. This ability of the drug can be useful to reduce hyperreactivity of the bronchi of patients with chronic renal insufficiency.


[Outpatient surgical treatment of chronic venous insufficiency of the lower extremities]. The results are analyzed for 30 surgical interventions on the legs for chronic venous insufficiency. Feasibility is considered of surgical correction of the function of the deep vein valvular apparatus, of retrograde circulation arrest by obturation of posterior tibial veins in varicosity and postthrombotic diseases.


[Surgical strategy in acute thrombophlebitis of the superficial veins of the lower extremities]. Active surgical policy in combined treatment of 98 patient with acute thrombophlebitis of the leg superficial veins provided good short- and long-term results in 73 of them. Urgent surgery was performed in cases with ascending thrombophlebitis of the large saphenous vein or thrombus location in the saphenofemoral anastomosis. No lethal outcome due to operative interventions were registered whereas conservative therapy resulted in 2 deaths from pulmonary artery thromboembolism.


[Metabolic polyneuropathy in pregnancy]. Clinical analysis of 4 polyneuropathies developed in pregnancy revealed that the characteristic features of the peripheral nerve lesions were their development in the presence of mildly pronounced gestosis and erythronormoblastic anemia (in all cases but one) that contradicted to the most typical descriptions in the literature. Polyneuropathic syndrome was also featured by the formation of severe indolent paralysis of extremities and manifest vegotovascular trophic lesions. Deeper sensitivity disorders failed to be revealed, whereas superficial sensitivity was compromised but insignificantly. Persistent residual paretic manifestations and acroangiodystonias were characteristic features of the performed observations.


On Fröhlich's coherent effects in biological systems: influence of carriers and high order dissipative effects. Following Fröhlich we consider a system that models a biological one, for example, a long chain of proteins possessing polar modes of vibration and where energy is pumped through metabolic processes. We consider the effect produced by free electrons that are usually present as hole carriers in proteins with electron-donor molecules. A theory of relaxation based on the non-equilibrium statistical operator method is used in the derivation of the kinetic equations to introduce non-linearities due to interactions of the polar vibrations with the carriers and with a thermal bath. These non-linearities arising from high order relaxation processes lead to the emergence of the Fröhlich effect in the polar modes, i.e. the occurrence of a (non-equilibrium) Bose-Einstein-like condensation. It points to an instability of the system that seems to be followed by a morphological transformation in the form of a spatially ordered dissipative structure.


Local probes and heterogeneous catalysis: a case study of a mitochondria-luciferase-hexokinase coupled system. Biological systems are characterized by a high degree of structural organization. In the intracellular context, this introduces physical constraints which are not considered in the standard biochemical analysis of isolated systems, aimed towards mechanistic studies. A major challenge in cellular biology is thus to integrate the structural and mechanistic information and reach an adequate representation of the modes of operation in situ. We present an approach to this problem which takes advantage of a localized probe to study heterogeneous coupled system, as minimal models for cellular operation. The system consists of ATP production at the surface of mitochondria, and ATP consumption in solution by the hexokinase reaction. Soluble or biologically localized firefly luciferase is used to continuously monitor ATP concentration either in the bulk solution or at the surface of the organelle, respectively. The general system of a surface source and a bulk sink is mathematically modeled, and an analytic steady-state solution for local and bulk ATP is presented. The results are validated by experiment and differ from the expected behavior of an equivalent homogeneous system in solution. The model is further adapted to evaluate the effect of mixing. In addition, two limiting cases of heterogeneous distribution of hexokinase are analyzed, in which the soluble enzyme adsorbs non-specifically to mitochondria, or binds selectively to the site of ATP appearance on the membrane. The results are discussed in terms of their significance to the analysis of bulk measurements in vitro and their relevance to better description of cellular situations.


Continuum model of fibroblast-driven wound contraction: inflammation-mediation. We propose a mathematical model to aid the understanding of how events in wound healing are orchestrated to result in wound contraction. Ultimately, a validated model could provide a predictive means for enhancing or mitigating contraction as is appropriate for managing a particular wound. The complex nature of wound healing and the lack of a modeling framework which can account for both the relevant cell biology and biomechanics are major reasons for the absence of models to date. Here we adapt a model originally proposed by Murray and co-workers to show how cell traction forces can result in spatial patterns of cell aggregates since it offers a framework for understanding how traction exerted by wound fibroblasts drives wound contraction. Since it is a continuum model based on conservation laws which reflect assumed cell and tissue properties, it is readily extended to account for emerging understanding of the cell biology of wound healing and its relationship to inflammation. We consider various sets of assumed properties, based on current knowledge, within a base model of dermal wound healing and compare predictions of the rate and extent of wound contraction to published experimental results.


Leukocyte deformability: finite element modeling of large viscoelastic deformation. An axisymmetric deformation of a viscoelastic sphere bounded by a prestressed elastic thin shell in response to external pressure is studied by a finite element method. The research is motivated by the need for understanding the passive behavior of human leukocytes (white blood cells) and interpreting extensive experimental data in terms of the mechanical properties. The cell at rest is modeled as a sphere consisting of a cortical prestressed shell with incompressible Maxwell fluid interior. A large-strain deformation theory is developed based on the proposed model. General non-linear, large strain constitutive relations for the cortical shell are derived by neglecting the bending stiffness. A representation of the constitutive equations in the form of an integral of strain history for the incompressible Maxwell interior is used in the formulation of numerical scheme. A finite element program is developed, in which a sliding boundary condition is imposed on all contact surfaces. The mathematical model developed is applied to evaluate experimental data of pipette tests and observations of blood flow.


Female infanticide and human sex ratio evolution. The possible effect on the evolution of the human sex ratio of a preference for male children is examined in a genetic model. It is shown that the killing of infant daughters can lead to either a female- or a male-biased sex ratio, the outcome depending on the decision rule used to determine the fate of a child. This reconciles long-standing contradictory results.


Plastid origin of an extrachromosomal DNA molecule from Plasmodium, the causative agent of malaria. Several species of Plasmodium have been shown to contain a circular extrachromosomal DNA molecule which is widely supposed to be mitochondrial DNA. However, it has recently been shown to have a number of features in common with chloroplast DNA. Here, a phylogenetic analysis of RNA polymerase coding sequences from the Plasmodium molecule has been carried out using distance matrix, maximum likelihood, parsimony and operator invariant methods. The analysis indicates that the molecule is in fact derived from an oxygenic photosynthetic organism and should be regarded as plastid DNA. This suggests that Plasmodium originated from a phototroph that has lost the capacity to photosynthesize.


The chirality of ground DNA knots and links. The chirality of ground DNA knots and links is described and characterized in terms of color symmetry groups (CSG), i.e. color symmetry groups I and II, which correspond to topochirality (topological chirality) and topoachirality (topological achirality) which bear an uncanny resemblance to point groups I (proper) and point groups II (improper) used for testing geochirality (geometrical chirality) and geoachirality (geometrical achirality), respectively. By regarding these two crossing modes in mirror images as white and black vertices, DNA knots and links with minimal crossings can be mapped to vertex-bicolored graphs under a working hypothesis that DNA knots and links exist in ground states with minimal energy m0. The color symmetry group of a vertex-bicolored graph G is defined as the set of all permutations and permutation asymmetrizations of the vertices of G that preserve its topology (connectivity), where asymmetrization, denoted as (a), is the operation of changing vertices' colors, and a permutation followed by an (a) is a permutation asymmetrization. The color symmetry groups I contains only permutations, whereas color symmetry groups II comprise permutation asymmetrizations as well as permutations. Four DNA knots and links in nature are analyzed and tabulated consisely. In addition, the well-known figure-of-eight knot and Borromean rings are discussed in much the same way.


Pattern generator system as a versatile visual stimulator. We have designed and implemented a Motorola 68000 microprocessor-based pattern generator system (PGS) that uses a color video display terminal (VDT) to provide light stimuli to the intact vertebrate retina. This communication is intended for those who are considering acquisition of a commercial retinal stimulator or those who are custom designing their own pattern generator system. The discussion surveys the features to be included as well as design factors which must be considered in such a device. The memory organization of the PGS allows as stimuli multiple, complex patterns consisting of one or more disks, annuli, bars or gratings to flash or modulate in intensity according to a pre-defined function. In addition, patterns can move smoothly in any direction at selectable, uniform speeds without the re-drawing of video memory. The presence of a 12-bit A/D converter internal to the PGS allows a dynamic change in stimulus position, speed or pattern based upon physiological feedback. A physically realistic image size (0.9 cm2) and resolution (20 mu/pixel) in the retinal plane are achieved with simple intervening optics. The video field rate of 60 Hz is above the flicker fusion frequency for most vertebrate animals and does not induce artifacts in cellular responses. The PGS operating in a PC-based environment meets the requirements of a versatile optical stimulator for investigations in retinal electrophysiology.


A sensitive ELISA for glial fibrillary acidic protein: application in CSF of children. In the present study we describe a sensitive ELISA for determination of glial fibrillary acidic protein (GFAP). To validate the method combined determinations of GFAP and S-100 protein were performed in cerebrospinal fluid (CSF) of normal children and children with autism. The GFAP ELISA is of sandwich type and uses the biotin-avidin system. Sensitivity was 16 pg/ml. Between-day precision was 0.079 (coeff. of variance). S-100 protein concentrations were measured using a commercially available ELISA kit. Normal CSF from children and young adults were analysed. The CSF levels of GFAP in normal children were low (16-163 pg/ml). Both GFAP and S-100 protein concentrations correlated with age (P < 0.01 and P < 0.05, respectively), but the GFAP increment was more pronounced, probably reflecting the age-dependent expansion of the fibrillary astrocytes in the central nervous system (CNS). GFAP levels in children with infantile autism were higher than those in normal children of the same age range. S-100 protein concentrations were similar in both groups. High levels of GFAP in combination with normal S-100 protein concentrations in CSF indicates reactive astrogliosis in the CNS. In conclusion, the sensitive ELISA described makes it possible to measure low levels of GFAP present in the CSF of children. Combined assays of GFAP and S-100 protein can be used to discriminate between acute and chronic brain disorders in children.


Rat exploratory behavior controlled by intracranial self-stimulation improves the study of place cell activity. This report is limited to the description of a procedure that should help to resolve the question whether firing fields of hippocampal place cells are relatively stable or modifiable by learning. Rats implanted with lateral hypothalamic electrodes for rewarding intracranial self-stimulation (ICSS) were trained to explore a circular open field (100 cm in diameter) while their locomotion was tracked by a computerized video system which also delivers ICSS whenever the animal's exploration has met certain experimenter defined criteria. The 3 following conditions were examined. (1) Homogeneous exploration of the entire field: ICSS was delivered after the animal repeatedly visited 5 equal segments of the field (central annulus and remainders of the 4 quadrants), entered randomly located circular areas of the field, and/or traveled a criterion distance. (2) Place field contingent reward or non-reward: ICSS was delivered when the animal entered a circular area (23 cm in diameter) corresponding to the place field after a previous visit to a similar area outside the place field. These conditions were reversed in the following task. (3) Delayed reward: ICSS was delivered when the animal entered the circular area and remained in it for 2 s. Each condition was tested for 600 s or until 50 ICSS were delivered. The behavioral procedures described make it possible to propose an experimental protocol that allows examination of the same place cell under conditions of homogeneous exploration with a segment condition or randomly distributed reward and under conditions with the place field signaling reward or non-reward. The delayed reward condition increases the accuracy of the target location and allows assessment of the phasic versus tonic nature of the place cell firing.


A simple electronic device for time-lapse recording of neural and other cell movements using a home video cassette recorder. This article describes a simple electronic unit to obtain time-lapse recordings with the use of a common remote-controlled home video cassette recorder, for example a VHS recorder. The electronic unit is a timer to be connected to the remote-control unit. The video cassette recorder itself remains unchanged. Replay of the recorded images speeds up the original process by a factor of 2-100 x or more. This technique has been applied in video micrographic studies of (1) the development of dorsal root ganglion (DRG) cells in culture, including growth cone and Schwann cell movements, and (2) tumor cell killing by natural killer (NK) cells.


Intracellular injections of permanent tracers in the fixed slice: a comparison of HRP and biocytin. Here we describe a method for intracellularly injecting mixtures of the fluorescent dye Lucifer Yellow and the permanent tracers HRP or biocytin into aldehyde-fixed slices of the dorsal lateral geniculate nucleus in young postnatal cats. Lucifer Yellow was used for visual control in the injection procedure and the inclusion of HRP or biocytin allowed the subsequent use of simple histochemical processing to give a permanent record of the injected cells. Both tracer mixtures revealed the dendritic morphology of injected cells. However, HRP was found to be superior to biocytin, in that dendrites were better defined and fine details of cellular morphology such as spines were consistently revealed. Using this technique we were able to demonstrate that the dendritic morphology of geniculate cells is much more mature between birth and 2 weeks than was thought from previous studies using Golgi methods.


Computer simulation of the blood-brain barrier: a model including two membranes, blood flow, facilitated and non-facilitated diffusion. A mathematical model of blood-brain barrier (BBB) transport was developed to assist in experimental design and data analysis. The model includes the luminal and antiluminal endothelial cell membranes, each with separate transport systems. Substrate movement between 3 compartments can be calculated: the capillary lumen, the endothelial cell cytoplasm, and the brain parenchyma. Blood flow, substrate concentration and competition in each compartment, concentration gradients along the capillary, and non-steady-state conditions are considered. The utility of the model is demonstrated by predicting: (1) complex concentration profiles along the length of the capillary lumen under different circumstances, (2) the permeability-surface area products along the capillary lumen, (3) the time course of events during brain-uptake index (BUI) experiments, (4) the accuracy of the BUI in measuring glucose transport over a range of endogenous glucose concentrations, (5) the influence of 2 membranes in series with different kinetic constants, and (6) a comparison of kinetic constants expected from high-flow infusion and BUI experiments.


Production of a serial position effect in rats using a 12-arm radial maze. The effects of item position (the serial position effect: SPE) on the recognition of a list of arms presented in an 8-arm radial maze have not been shown to be robust across studies which differ in numbers of subjects, amount of training and task difficulty. The present study examined whether more robust SPEs could be obtained in rats with a 12-arm radial maze using a matching-to-sample serial probe recognition (SPR) procedure. In Part 1, 23 rats received extensive training on recognition of list of arms from a 5-arm list and, in Part 2, 20 rats received training with a 7-arm list. Both Parts 1 and 2 showed that a reliable and persistent SPE emerged due to superior recognition of items at the first and last serial positions compared with the middle positions. However, the SPE was more pronounced with the 7-arm than 5-arm list. It is argued that adequate task difficulty along with sufficient subject and trial numbers is necessary to produce a clear SPE. In Part 3, an alternative means of assessing accuracy derived from signal-detection theory is examined, and the procedural requirements for its use are identified. Although this measure did not alter the conclusions reached using percent correct, it is proposed that the bias-free measure, log d, is superior to traditional indices of memory performance which may obscure the presence of, or changes in, the SPE. The procedures used here provide a valuable means to produce clear, reliable and persistent SPEs. Such procedures are essential if researchers are to be confident about the effects of lesions or drugs upon list memory in their attempts to explore the neurological bases of memory and model human neurological disorders.


Photochromic intensification of diaminobenzidine reaction product in the presence of tetrazolium salts: applications for intracellular labelling and immunohistochemistry. The diaminobenzidine (DAB) reaction product can be greatly intensified by incubating the reacted tissue in either nitro blue tetrazolium or tetranitro blue tetrazolium and then exposing the tissue to strong light. Epi-illumination through a microscope objective enables the photochromic intensification to be carried out under direct visual control, with optimal intensification taking only 10-30 s through a 20x objective. Alternatively, the whole preparation can be intensified in a few minutes by passing it back and forth under a fibre light guide. The method can be used to intensify cells that have been labelled either by immunoperoxidase techniques or with intracellular tracers such as horseradish peroxidase and neurobiotin.


Slices from the rat olfactory bulb maintained in vitro. Morphological aspects. Transverse, 400-microns-thick slices of 8-day-old rat olfactory bulb were incubated in Krebs-Henseleit medium with and without oxygenation. Following incubation, slices were fixed in aldehyde-osmium and embedded in resin for light and electron microscopy. After 2 h of incubation oxygenated preparations showed a structural preservation comparable to that of the freshly fixed olfactory bulb. Under hypoxic conditions mitral cells located on the medial side of the bulb were the most sensitive to the interruption of gassing, while ventricular cells and glomeruli were remarkably resistant as judged by morphological standards. The effects of short-term (up to 30 min) interruptions of gassing proved to be reversible. Our findings suggest that the incubated olfactory bulb slice may be a useful preparation for functional morphological studies.


The effects of low-pass filtering on the flash visual evoked potential of the albino rat. Flash visual evoked potentials (FVEPs) were recorded from the rat in order to determine the effects of low-pass filtering on the wave form. The low-frequency (high pass) filter remained fixed at 3.2 Hz while the setting of the high-frequency (low-pass) filter was progressively raised from 32 Hz to 3.2 kHz. The amplitude of the primary cortical potential (P30) steadily increased while its latency decreased until asymptotic values were recorded with a low-pass cut-off of 320 Hz. Thereafter, there was little additional change in wave form. It is concluded that a bandpass of 3.2-320 Hz is optimal to record the primary cortical response of the FVEP, and this is consistent with the theory that the P30 potential is generated by comparatively slow post-synaptic activity. In a second experiment the effects of low-pass filtering were examined on the later and more labile secondary components of the FVEP wave form. These were found to be less responsive to low-pass filtering than the early components and assumed a near optimal configuration when the high-frequency cut-off was raised to 80 Hz. The high-frequency filter setting which is most appropriate to record the primary component of the FVEP therefore appears to be more than adequate also to record the secondary responses. It is also shown that the same principles of low-pass filtering on the FVEP will apply irrespective of whether the subject is awake or anaesthetised.


Further refinement of the Escherichia coli brain abscess model in rat. The rat brain abscess model provides a substrate for the modeling of delivery of therapeutic agents to intracerebral mass lesions. We now report refinement of the Escherichia coli brain abscess model in rat. A K1 surface antigen-negative E. coli isolated from human blood culture was stereotaxically inoculated into deep brain sites. Histopathologic analyses and quantitative cultures demonstrated the consistent production of lesions. No animal in this consecutive series developed meningitis, ventriculitis or sepsis. By contrast, prior experience with E. coli abscess production resulted in 25% failure rate of abscess production or death from sepsis. This improvement in the model may be attributable to specific characteristics of the bacteria used, modification of the inoculation method or the intracerebral placement technique. The present work suggests a reliable and consistent brain abscess model, which may be further used to study brain suppuration.


An intracellular medium formulary.

An intracellular medium formulary. Whole-cell patch-clamp recordings allow diffusible intracellular ions and molecules to be replaced by the contents of the recording pipette. In this review, the formulation of intracellular media is considered with a view to improving the stability of recordings and emulating the intracellular environment.


Relationship between endothelin and thromboxane A2 in rat liver microcirculation. In our previous study, we determined changes in hepatic blood flow using a Laser Doppler blood flow meter after i.v. injection of endothelin-1 (ET-1) or endothelin-3 (ET-3) at 2 nmol/kg in rats and found that ET-3 caused greater decreases in blood flow than ET-1. In the present study, we determined how the arachidonic acid cascade, mainly thromboxane A2 (TXA2), is related to ET-1 and ET-3 using indomethacin (INDO), which inhibits the biosynthesis of prostaglandin (PG), and OKY-046, a selective inhibitor of TXA2 synthesis. In the first series of experiments, ET-1 and ET-3 were administered after inhibiting the biosynthesis of PG by s.c. injection of 2 mg/kg of INDO. While INDO failed to inhibit the slight decrease in hepatic blood flow induced by ET-1, it significantly inhibited the marked decrease in hepatic blood flow elicited by ET-3. In the next series of experiments, ET-1 and ET-3 were administered after administration of 20 mg/kg of OKY-046. OKY-046 showed no effects in animals treated with ET-1, as in those pre-treated with INDO, while it significantly inhibited the decreases in hepatic blood flow induced by ET-3. These findings suggest that ET-1 decreases hepatic blood flow due to its direct effects although to a lesser extent than ET-3, while ET-3 does so due not only to its direct effects but also to TXA2-mediated effects. It is therefore likely that in addition to ET family peptides, PG-mediated mechanisms are involved in the regulation of hepatic microcirculation by ETs.


Light-dark variations in ocular timolol concentrations following topical solution instillation in the pigmented rabbit. The objective of this study was to determine whether ocular absorption of topically applied timolol in the pigmented rabbit varied with the time of drop instillation. Twenty-five microliters of a 0.65% timolol maleate solution were instilled in the pigmented rabbit eye at 0600, 0900, 1200, 1500, 1800, 2100, 2400, or 0300 hr. Timolol concentrations in the conjunctiva, sclera, corneal epithelium, corneal stroma, aqueous humor, and iris-ciliary body at 15 and 30 min post-dosing were monitored using reversed phase HPLC. Ocular timolol concentrations were higher when the drug was administered during the light period (0900-1800 hr) than when it was administered during the dark period (1800-0600 hr). There exist, therefore, light-dark variations in the ocular absorption of topically applied timolol.


Cloricromene antagonizes antidipsogenic effects induced by endotoxin, but not by TNF alpha, in the rat. Intravenous (640 micrograms/kg) or intracerebroventricular (0.5 and 1 microgram) injection of Escherichia coli endotoxin (LPS) causes inhibition of water intake induced by 24 hour period of water deprivation in the rat. Tumor necrosis factor alpha (TNF-alpha; 20 and 40 ng/rat) given into the lateral cerebral ventricle (i.c.v.) causes effects similar to those observed after LPS. Cloricromene, given either intravenously (1 and 2 mg/kg) or i.c.v. (250 and 500 ng), abolished the antidipsogenic effect induced by LPS (administered both i.v. and i.c.v.). Cloricromene (2 mg/kg, i.v. or 500 ng/rat, i.c.v.), on the contrary, did not modify the antidipsogenic effects induced by TNF-alpha. These data indicate that peripherally injected cloricromene (as well as that i.c.v. injected) antagonizes the effects of mediators of LPS on sites regulating thirst and suggest that cloricromene's action may be due to inhibition of brain TNF-alpha formation induced by LPS.


Heme polymerase: modulation by chloroquine treatment of a rodent malaria. The biosynthesis of the beta-hematin of malarial pigment (hemozoin) is catalyzed by a newly discovered enzyme, heme polymerase, which is described for Plasmodium berghei in this report. This novel enzyme is present in the insoluble fraction of hemolysates of infected erythrocytes but is not present in normal erythrocytes. The substrate is ferriprotoporphyrin IX (FP) released from hemoglobin. At pH 5 and 37 degrees C the enzyme is saturated by 100 microM FP. The pH optimum is between 5 and 6 and the reaction is linear for 6 hours. All heme polymerase activity is destroyed by heating at 100 degrees C for 3 minutes. Chloroquine treatment of malarious mice reduces by 80 percent the activity of this enzyme, without inhibiting release of FP from hemoglobin, and thereby causes excess nonpolymerized, nonhemozoin FP to accumulate. Since the accumulated FP is accessible to bind chloroquine, we propose that it is the mediator of the antimalarial activity of chloroquine.


Time-dependent anesthetic and anticonvulsant activities of alphaxalone in Syrian hamsters. To assess whether the anesthetic and anticonvulsant activities of alphaxalone display diurnal variability, groups of Syrian hamsters were studied at 4 h-intervals during a 24 h-cycle. The administration of alphaxalone (5 mg/kg) brought about a greater anesthetic activity (loss of righting reflex) at the middle of the photophase. When assessed in hamsters injected with 3-mercaptopropionic acid, alphaxalone displayed maximal anticonvulsant activity at the 4th of darkness. Evaluation of the time needed for first convulsive response indicated that alphaxalone did not show time-dependent effects, while in control hamsters seizure threshold was low during daylight and attained maximal values at night, showing a peak in seizure threshold at light-dark transition.


[Noninvasive determination of oxyhemoglobin in arterial blood]. The authors describe the principles of noninvasive measurements of oxyhemoglobin content in the arterial blood by processing the signals obtained as a result of passing the light waves of the infrared (940 nm) and red (660 nm) wave bands through tissues. The data obtained with the first Russian pulse oximeter and with the hemoximeter were found to coincide. The diagnostic value of oximetry is discussed.


[Determination of oxygen saturation of circulating blood from pulse wave amplitude]. The oxygen saturation of circulating blood (SaO2) can be determined from the modulation depth of luminous flux passing through the tissue filled with pulsing blood. For calculation of SaO2, an equation has been derived from the output signal amplitude of the current-voltage transducer.


[Principles of optical oximetry in extracorporeal circulation systems]. The paper outlines the optical properties of blood as a random unhomogenous scattering and absorbing medium and presents the basic characteristics of single erythrocyte diffusers. It also shows how the above dependencies are used in particular oximeters. The first world's laser oximeter designed by the authors is described.


[Use of zirconium alloys in endoprostheses and osteosynthesis appliances]. The application of titanium alloys to osteosynthesis appliances and endoprostheses in becoming difficult due to shortage of titanium. The composition of the BT5-I titanium alloy and comochromium and zirconium alloys was compared. In terms of mechanical properties, the zirconium alloys are acceptable for the above application.


[High-quantum-outlet red and infrared radiation for oximetry]. The paper deals with the results of designing highly effective semi-conductor red and infrared radiators based on the multitransient double heterostructures in the Ga1-xAlxAs system and structures in the GaAs:Si, which are designed for oximetry, and presents a small-sized (2.5 x 2.5 x 2.4 mm) unit with flexible terminals. The emissive power was as great as 1.3 mW at 10 mA at lambda max 660 +/- 10 nm in the red band and 1.2 mW at lambda max 925 +/- 10 nm and 2.5 mW at lambda max 870 +/- 20 nm in the infrared band. The radiators described have wide prospects for practical application to oximeters and other medical equipment.


[Tussograph, a device for monitoring tussive impulses]. The paper describes the basic circuit of a tussograph, a device that monitors cough in patients with bronchopulmonary diseases. An NKT-I makes it possible to calculate the number of tussive expulsions, total and peak expulsions, as well as to record their time distribution. The device may be useful in the study into the efficacy of new antitussive drugs and the assessment of cough clearance. It can provide an insight into mucociliary clearance.


[Reconstruction of images in emission tomography]. The algorithm of back projection with filtration for exponential Radon transform leads to strong distortion for big diameter objects. The main reason for this distortion is mainly the exponential increase of errors in the quadrature formula for a weighed back projection operator. So it is sometimes more convenient to use the back Radon transform R-1 and then to correct the result, taking into account attenuation. For this purpose, the approximation formulas are given, which connect f and R-1 R mu f. An appropriate iteration reconstruction algorithm is also considered. Application exponential Radon identities for projection data analysis are also discussed.


[Device for analysis of electrocardiograms]. A new device has been proposed for in-depth analysis of cardiac and vascular performance recording. It determines the values of many quantitative parameters for cardiovascular performance and makes an amplitude analysis of the records. The device is simple and easy-to-use. It promotes interpretation of the records. The application of the device in the laboratories of functional diagnosis will reduce time spent on record analysis and expands the range of quantitative parameters to a great extent, which will enable the proper diagnosis of cardiovascular diseases to be established.


[Echo-AM1-1 encephaloscope].

[Echo-AM1-1 encephaloscope]. A new miniature model of the A-mode ultrasonic echoencephaloscope, 0.88 MHz, has been developed and adopted to practical use in neurology. The device contains a detector for amplitude determination of echopulsation and curve (echopulsograms) recording. It is highly sensitive, cost-effective, which enhances the quality of rapid diagnosis of central nervous diseases, including those of vascular genesis, in in- and outpatient settings.


[Trends in the development of technology for thermal irradiation of the human body]. The paper analyzes trends in development of advanced thermal irradiation technology which increases the three-dimensional selectivity of radiation and elevates the level of automatic targeted radiation source control through mathematical simulation of technology and irradiation objects. It also presents concepts of adaptive irradiation and problems in the construction of mathematical models.


[Methods of testing, programmed and metrological support of multidetectors for radionuclide dynamic studies]. The paper deals with the specific features of metrological support of multidetectors designed for radionuclide diagnosis. A procedure is proposed to monitor the technical data of KP RDI-2A and KP RDI-3A devices. The functional potentialities of basic and metrological support of these devices are outlined.


[The genetics of Alzheimer's disease].

[The genetics of Alzheimer's disease]. This paper examines recent epidemiological and molecular genetic studies on the genetic basis of Alzheimer's disease (AD). Recent epidemiological studies have shown the existence of a genetic etiology in some cases of Alzheimer's disease. Several pedigrees with an increased incidence of AD (familial Alzheimer's disease--FAD) have been described in the literature. Some of these contain sufficient numbers of affected individuals in multiple generations to provide a rigorous argument for an autosomal dominant inheritance of the AD phenotype. FAD pedigrees show several evidences of as phenotypic heterogeneity of the disease. Molecular genetic studies have shown a linkage between several polymorphic DNA markers specific for the pericentromeric region of chromosome 21 and early-onset FAD. In late-onset FAD pedigrees preliminary reports showed evidence for a linkage with chromosome 19 markers. Molecular genetic studies have clearly demonstrated the genetic heterogeneity of familial Alzheimer's disease. The analysis of new, multigenerational pedigrees with FAD and the study of patients with Down's syndrome and Alzheimer's disease should provide useful informations for the characterization of the gene(s) responsible for familial Alzheimer's disease.


[Hyponatremia, cause of reversible dementia in the elderly]. There are several states of reversible dementias. Among these, electrolyte imbalance--especially hyponatremia--can determine transitory modification of cognitive functions. The purpose of this study is the evaluation of the relationship between cognitive disorders and serum sodium concentrations in the elderly. In a sample of 70 elderly people, the Authors reported a prevalence of hyponatremia in 28 patients (40%); only 4 (5.7% of total population) had impaired cognitive functions or mood disturbances. In the symptomatic patients hyponatremia was severe and had a fast onset; the symptoms disappeared by means a proper and ready treatment. This observation stresses out the importance of routine serum sodium determination in the elderly in coincidence with the sudden onset of a pattern of dementia.


[Psychosomatic assessment in patients with gravidic hyperemesis]. Thirty female subjects examined in the first three months of pregnancy took part in the study. Ten of these suffered from severe gravidic hyperemesis, while twenty had a physiological pregnancy. All subjects with hyperemesis and six controls were subjected to measurement of cortisolaemia at the following times: 8, 12, 16, 20, 24 and 4.00 so as to obtain the circadian curve of the hormone, measurement of T3 and T4 and of TSH. The Cattell test in form C was carried out in all patients. The results obtained evidenced a global increase in the production of cortisol in the group of hyperemetic women, with maintenance of the circadian rhythm. The Cattell test identified characteristic personality traits in the subjects suffering from hyperemesis compared to the controls.


[The dexamethasone test and the choice of treatment and drug in depression]. A large body of literature data have indicated that the dexamethasone suppression test (DST) may be useful in diagnosing depression. It has been also hypothesized that depressed patients showing an abnormal response to dexamethasone administration ("DST-non suppressors") are responsive to the treatment with psychopharmacological agents whereas the "DST-suppressors" subjects are often "placebo-responders". Moreover, on the basis of considerations concerning the inhibitory role of noradrenaline in the control of both the activity of the hypothalamic-pituitary-adrenal axis and mood, it has been claimed that the "DST-non suppressors" subjects respond to the treatment with antidepressant drugs potentiating the noradrenergic activity at level of the central nervous system. The present review of the main data on the topic leads to conclude that the DST may be useful in selecting the most appropriate treatment for depressed patients; the test, however, does not make it possible to choose the antidepressant drug on the basis of its neurochemical profile.


[Fluoxetine and depression in the elderly. Clinical experience]. Eighty-six patients aged between 60 and 80 years and affected with major depression according to the diagnostic criteria of the DSM III-R were treated with fluoxetine per os at the single dosage of 20 mg/die. At prearranged intervals psychometric reagents were administered for the evaluation of any variations in the depressive symptomatology. Already at the 1st examination after 14 days' treatment a considerable improvement in the psychopathological picture was observed. This improvement remained constant at the subsequent examinations and the follow-up after 90 days. The tolerability was excellent and the side effect mild, with a tendency to regress after the first days of therapy. The clinical assessment and the psychometric findings both suggest that fluoxetine has a useful action on major depression in the elderly.


[Medico-biological and psychopathologic aspects of substance dependence]. The paper examines the phenomenon of drug addiction from a bio-socio-pathological point of view. Neurophysiological advances in the field of drug addiction reveal the correlations between biology and behaviour, thus allowing the creation of numerous synergic strategies at different levels of intervention.


Peroxisome biogenesis in yeast.

Peroxisome biogenesis in yeast. Eukaryotic cells have evolved a complex set of intracellular organelles, each of which possesses a specific complement of enzymes and performs unique metabolic functions. This compartmentalization of cellular functions provides a level of metabolic control not available to prokaryotes. However, it presents the eukaryotic cell with the problem of targeting proteins to their specific location(s). Proteins must be efficiently transported from their site of synthesis in the cytosol to their specific organelle(s). Such a process may require translocation across one or more hydrophobic membrane barriers and/or asymmetric integration into specific membranes. Proteins carry cis-acting amino acid sequences that serve to act as recognition motifs for protein sorting and for the cellular translocation machinery. Sequences that target proteins to the endoplasmic reticulum/secretory pathway, mitochondria, and chloroplasts are often present as cleavable amino-terminal extensions. In contrast, most peroxisomal proteins are synthesized at their mature size and are translocated to the organelle without any post-translational modification. This review will summarize what is known about how yeast solve the problem of specifically importing proteins into peroxisomes and will suggest future directions for investigations into peroxisome biogenesis in yeast.


[Psychology and the cancer patient].

[Psychology and the cancer patient]. Over the past thirty years, an abundant international production has been generated on the subject of this paper. Papers may be subdivided into two main streams, one with an assistential bent and the other psychosomatic. In its turn, the latter takes in certain studies relating to a psychological model and another group of writings is oriented in accordance with psychodynamic principles. Both aim to evidence a certain correlation between physical and mental phenomena. Psychobiological theories aim to provide a model of correlation between the set of psychophysiological phenomena known as stress and cancer, while the psychodynamic view proposes a correlation between cancer and the individual personality; specifically, the theories set out to explain how the personality structure of a number of individuals leads to their managing stress anomalously with the result that stress is involved in the development of cancer along with genetic and environmental factors. Within this latter context, a number of workers have defined typical anamnestic profiles on the basis of the evolution of such personalities. The present study concerns 44 cases used to examine the orientation of the international literature, above all for the purpose of elaborating psychotherapeutic techniques possibly working in synergy with medical techniques in the treatment of some of these patients.


Structure of selenocysteine synthase from Escherichia coli and location of tRNA in the seryl-tRNA(sec)-enzyme complex. Selenocysteine synthase of Escherichia coli catalyses the biosynthesis of selenocysteine in the form of the aminoacyl-tRNA complex, the reaction intermediate being aminoacrylyl-tRNA(sec) covalently bound to the prosthetic group of the enzyme. Selenocysteine synthase and the specific aminoacrylyl-tRNA(sec)-enzyme complex as well as the isolated seryl-tRNA(sec) were investigated in the electron microscope and analysed by means of image processing to a resolution of 2 nm in projection. The stoichiometric composition of the selenocysteine synthase molecule was elucidated by scanning transmission electron microscopic mass determination. The enzyme has a fivefold symmetric structure and consists of 10 monomers arranged in two rings. The tRNA is bound near the margin of the dimeric subunits. Principal component analysis of the tRNA-enzyme complexes revealed that the selenocysteine synthase appears to bind only one seryl-tRNA(sec) per dimer, which is consistent with the result of biochemical binding studies.


[Social support and mental distress. Epidemiologic studies]. The clinical and experimental model of social support connects some social phenomenon (as isolation and loneliness, involvement and relationships) to health or psychophysical distress. This review of epidemiologic research, carried on USA, point out: a) the epidemiologic correlation between support and health/distress; b) frequently, the phenomenon of stress "buffered" by social support; c) the onset of psychological distress linked on support's and stress level. The clinical and preventive intervention may gets some profit from the outcome of this epidemiologic research.


[Psychiatry and environment].

[Psychiatry and environment]. After having underlined the increasingly negative influence of environmental changes on human life, the paper focuses o their influence on the psyche which is subjected to a continual series of traumas caused by the abnormal rhythm of modern life and the lack of human solidarity and ideals. Because of their fragility, the greatest victims of this situation are the young, the old and women and the pay the greatest price by resorting to drugs, alcoholism, prostitution or new forms of reactive psychosis. This underlined the necessity for continual and intense preventive action.


[Psychiatric disorders in elderly patients with physical problems. Critical review of the recent literature]. The authors review some studies of the recent psychiatric literature on the elderly medically ill. The large variability in setting, screening instruments, and diagnostic criteria makes comparison of results somehow difficult and probably accounts for the differences in prevalence rates. We also outline methodological issues relating to the standardization of screening instruments and to special features ("pseudodementia", "masked" depression) of psychiatric disorders in old age.


Ribosomal association of the yeast SAL4 (SUP45) gene product: implications for its role in translation fidelity and termination. The SAL4 gene of the yeast Saccharomyces cerevisiae encodes a novel translation factor (Sal4p) involved in maintaining translational fidelity. Using a polyclonal antibody raised against a Sal4p-beta-galactosidase fusion protein, Sal4p was shown to be almost exclusively associated with the ribosomal fraction. Even when the ribosomes were treated with 0.8 M KCl, only low levels of Sal4p were detected in the post-ribosomal supernatant, suggesting a very strong affinity between Sal4p and the ribosome. Analysis of the distribution of Sal4p in the ribosomal population revealed that it was principally associated with 40S subunits, monosomes and polysomes. Incubation in high salt concentrations (0.8 M KCl) suggested that the affinity of Sal4p for the 40S subunit was lower than that for monosomes or polysomes. The Sal4p:ribosome association was only maintained when ribosomes were prepared in the presence of the translation elongation inhibitor cycloheximide; in uninhibited cells much lower levels of Sal4p were detectable in the 'run-off' polysomes. In view of these data, and given the stoichiometry of Sal4p to individual ribosomal proteins (estimated at less than 1:20), we suggest that Sal4p plays an ancillary role in translation termination.


[En epidemiologic approach for the analysis of the demand and supply of psycho-psychiatric care in general medicine and in specialized services]. In this paper we present data collected in the area of Verona concerning indicators of demand and of supply of care in two settings, the general practice and the South-Verona Community Psychiatric Service. These data, obtained from the epidemiological studies conducted by our research group during the past ten years, emphasize similarities and differences existing in the two levels of care. In general practice the demand for care for psychological disorders is difficult to identify, because of the frequent somatic expression of these disorders; moreover at the level of psychiatric services the demand is frequently aspecific. As far as the supply of care is concerned, in both settings drug prescription is the most frequent treatment, however other interventions are also offered. For example, in general practice counselling and referral to the psychiatrist are often provided; in psychiatric services monitored during our studies a large range of treatments were supplied, often in an integrated way.


Characterization of the minimal origin required for replication of the streptococcal plasmid pIP501 in Bacillus subtilis. By using deletional analysis the origin of replication, oriR, of the streptococcal plasmid pIP501 in Bacillus subtilis has been mapped at a position immediately downstream of the repR gene. Determination of both the right and left border of oriR allowed the definition of a sequence of a maximum of 52 nucleotides which theoretically constitutes the minimal origin of replication. Recently, the start point of leading-strand synthesis of the closely related plasmid pAM beta 1 has been mapped at a position which is located exactly in the middle of this sequence (Bruand et al., 1991). The function of oriR did not depend on its location downstream of the repR gene. Translocation of oriR-containing fragments to other regions of the plasmid proved to be possible. The smallest translocated fragment that still reconstituted autonomous replication was 72bp in size. This fragment was also active in directing the replication of an Escherichia coli plasmid in B. subtilis when the RepR protein was supplied in trans from a repR gene integrated into the host chromosome. The transformation efficiency of plasmids carrying translocated oriR fragments showed a certain dependence on the fragment length and orientation. The DNA sequence of oriR included an inverted repeat, both branches of which appeared to be essential for oriR function. The repeats of oriR shared sequence similarity with a repeat located upstream of promoter pII, which has been suggested to be involved in autoregulation of repR expression.


Tandem DctD-binding sites of the Rhizobium meliloti dctA upstream activating sequence are essential for optimal function despite a 50- to 100-fold difference in affinity for DctD. The Rhizobium meliloti genes dctB and dctD positively regulate the expression of dctA, which encodes a C4-dicarboxylate transport protein. Here we characterize an element (UAS) located upstream of dctA that has tandem binding sites for the dctD gene product (DctD). At relatively low concentrations of active DctD, the element activated dctA transcription, but at relatively high concentrations of DctD it was inhibitory. The UAS failed to function when placed further upstream of dctA. Both DctD-binding sites were required for optimal UAS function, despite a 50- to 100-fold difference in binding affinities. Moving the promoter distal binding site 5 bp further upstream was functionally equivalent to its deletion. Based on these data, we hypothesize that the sigma 54-dependent activator DctD binds co-operatively to the R. meliloti dctA UAS, and that occupancy of both sites is required for maximal activation of dctA.


[Emergency psychiatric services in Torino. Presentation of the activities]. The paper reports on the emergency psychiatric Unit (EPU) that has been instituted in Turin. A period of transformation in the philosophy of psychiatric departments, has led, among other things, to the approval of a regional law that can be considered as a local interpretation, of national legislation. The EPU is an experimental model that codifies the emergency level of intervention to stand alongside existing emergency medical facilities, including first-aid stations. The purpose of this first investigation is to examine the number and type of calls studying the data obtained so far is a fundamental stage in our understanding of the "emergency" phenomenon and in the construction of other levels of intervention aimed to optimise available resources.


The phosphorylation site of the Kdp-ATPase of Escherichia coli: site-directed mutagenesis of the aspartic acid residues 300 and 307 of the KdpB subunit. The potassium-translocating Kdp-ATPase of Escherichia coli shares common functional properties with eukaryotic P-type ATPases. The KdpB subunit has been identified as the catalytic subunit forming the phosphorylated intermediate. Substitution of Asp-307 in KdpB by Glu, Asn, Gln, Tyr, His, Ala or Ser by site-directed mutagenesis and the subsequent transfer of the point mutations to the chromosome revealed that the mutants were not functioning with respect to cell growth at low K+ concentrations and ATPase activity as well as phosphorylation capacity of the purified Kdp complex. These findings indicate that Asp-307 in KdpB is the phosphorylation site of the Kdp-ATPase. In contrast, replacement of the close but non-conserved Asp-300 by Asn or Glu has no immediate influence on the enzyme functions tested. However, the Km for K+ of the ATPase activity has been increased 30-fold compared with the wild-type enzyme.


Secretion of the STA3 heat-stable enterotoxin of Escherichia coli: extracellular delivery of Pro-STA is accomplished by either Pro or STA. The methanol-soluble, heat-stable enterotoxin of Escherichia coli is a protease-resistant extracellular peptide which is synthesized as a 72-amino-acid precursor Pre-Pro-STA3. The specific roles of Pre (19 amino acids), Pro (34 amino acids) and STA3 (19 amino acids) in the secretion process were studied by functionally deleting each of the three domains. Deletion of the Pre signal sequence resulted in a short-lived cell-associated molecule with an M(r) equivalent to that of Pro-STA3. Deletion of Pro (i.e., Pre-STA3) resulted in the rapid extracellular accumulation of STA3; the periplasmic intermediate found in the secretion of the wild-type toxin was undetected. Deletion of the STA3 domain resulted in a cell-associated Pre-Pro peptide; with time this form converted to periplasmic Pro which later became extracellular. When DNA encoding either STA3, by itself, or Pro-STA3 (lacking the signal peptide) was expressed, these peptides were degraded intracellularly, with no periplasmic or extracellular forms detected. The results presented demonstrate that the signal peptide (Pre) is essential even for the export of small peptides to the periplasm, and that its absence causes the STA3 domain to become susceptible to intracellular proteases. The rapid degradation of intracellular STA3 indicates that its proteolytic resistance is acquired in a compartment other than the cytoplasm. The results also show that after the Pre domain is proteolytically cleaved from Pre-STA3 and Pre-Pro, the STA3 and Pro peptides can exit to the culture supernatant.(ABSTRACT TRUNCATED AT 250 WORDS)


Streptomycetes possess peptidyl-prolyl cis-trans isomerases that strongly resemble cyclophilins from eukaryotic organisms. A functionally active 17.5 kDa peptidyl-prolyl cis-trans isomerase was purified to homogeneity from Streptomyces chrysomallus, a Gram-positive filamentous bacterium. Characterization of the enzyme revealed inhibition and binding characteristics, against the immunsuppressive drug cyclosporin A, which were similar to cyclophilins from eukaryotes such as mammals, plants, fungi and yeasts, but different from those of cyclophilins from enterobacteria such as Escherichia coli. The amino acid sequence of the S. chrysomallus cyclophilin, as deduced from the gene sequence, revealed a striking degree of amino acid sequence identity with the corresponding 17 kDa proteins of humans (66%), Neurospora (70%) and yeast (69%). Comparison with cyclophilin sequences from the Gram-negative enterobacteria revealed much less homology (25% identity with E. coli b, 23% identity with E. coli a). Cyclophilin was detected in each of the four other Streptomyces species tested. The cyclophilins from the various streptomycetes differed in size, varying between 17 and 20.5 kDa. The cyclophilins were abundant in the Streptomyces cells, and present throughout growth.


A reorganized Candida albicans DNA sequence promoting homologous non-integrative genetic transformation. In order to develop plasmids adequate for non-integrative genetic transformation of Candida albicans, a DNA fragment of 15.3 kb was cloned from this organism on the basis of its capacity to convert the integrative Saccharomyces cerevisiae vector YIp5 into a non-integrative one. Southern hybridization analysis, carried out with a labelled DNA probe of 3.6 kb derived from the cloned fragment, showed that it consisted of C. albicans DNA, the hybridization pattern indicating that the corresponding sequences were homologous to several chromosomal regions. The size of the C. albicans DNA promoting autonomous replication in S. cerevisiae was substantially reduced by subcloning. A 5.1 kb subfragment, defined by BamHI and SalI restriction sites, retained autonomous replication sequences (ARS) functional in the heterologous S. cerevisiae system and in C. albicans, when inserted in plasmid constructions that carried a S. cerevisiae trichodermin-resistance gene (tcm1) as selection marker. C. albicans transformants were both of the integrative and the non-integrative type and the plasmids recovered from the latter very often carried a reorganized ARS, indicating that recombination of the inserted ARS DNA had occurred in the homologous host. Successive reorganizations of the ARS insert in C. albicans eventually led to a more stable and much smaller fragment of 687 bp that was subsequently recovered unchanged from transformants. Sequence analysis of the 687 bp fragment revealed four 11-base blocks, rich in A+T, that carried the essential consensus sequence considered relevant for yeast ARS elements in addition to other features also described as characteristic of yeast replication origins.


Broad-host-range Rhizobium species strain NGR234 secretes a family of carbamoylated, and fucosylated, nodulation signals that are O-acetylated or sulphated. Rhizobium species strain NGR234 is the most promiscuous known rhizobium. In addition to the non-legume Parasponia andersonii, it nodulates at least 70 genera of legumes. Here we show that the nodulation genes of this bacterium determine the production of a large family of Nod-factors which are N-acylated chitin pentamers carrying a variety of substituents. The terminal non-reducing glucosamine is N-acylated with vaccenic or palmitic acids, is N-methylated, and carries varying numbers of carbamoyl groups. The reducing N-acetyl-glucosamine residue is substituted on position 6 with 2-O-methyl-L-fucose which may be acetylated or sulphated or non-substituted. All three internal residues are N-acetylated. At pico- to nanomolar concentrations, these signal molecules exhibit biological activities on the tropical legumes Macroptilium and Vigna (Phaseoleae), as well as on both the temperate genera Medicago (Trifoliae) and Vicia (Viciae). These data strongly suggest that the uniquely broad host range of NGR234 is mediated by the synthesis of a family of varied sulphated and non-sulphated lipo-oligosaccharide signals.


Molecular analysis of the aroA gene of Pasteurella multocida and vaccine potential of a constructed aroA mutant. The aroA gene from Pasteurella multocida was cloned by complementation of the Escherichia coli aroA mutant AB2829 with a DNA library constructed in pUC18. The nucleotide sequence of the P. multocida aroA gene indicated an open reading frame encoding a protein of 441 amino acids, which showed a high degree of homology with the amino acid sequences of various other bacterial AroA proteins. The cloned P. multocida aroA gene was inactivated by insertion of a kanamycin-resistance gene and reintroduced by allelic exchange into the chromosome of P. multocida using the suicide vector pJM703.1. The P. multocida aroA mutant was highly attenuated in a mouse model. Mice immunized intraperitoneally with two doses of live P. multocida aroA mutant were completely protected against a lethal parental strain challenge.


Identification of functional cis-acting sequences involved in regulation of narK gene expression in Escherichia coli. Expression of the narK gene of Escherichia coli, like the narGHJI operon, is positively regulated by two trans-acting factors: Fnr, which is activated by anaerobic conditions, and NarL, which is activated by the conditions, and NarL, which is activated by the presence of nitrate. Unlike the narGHJI operon, the 5' untranslated region of the narK gene contains two putative Fnr-binding-site sequences and two putative NarL-binding-site sequences. To define the role of these putative cis-acting regions, transcription start sites were identified and the effects of promoter region modifications on transcription were determined. Primer extension analysis identified several transcripts for the narK gene expressed from plasmids. Expression from the major promoter, P1, was induced by anaerobic growth conditions and further elevated in the presence of nitrate, while that from a weaker promoter, P2, appeared to be constitutive. The position of the major transcription start site placed one of the putative Fnr-binding sites (Fnr1 box) and one of the NarL-binding sites (NarL2 box) at positions analogous to those previously established for the narGHJI operon promoter region, while the other two binding sites were located in the non-homologous 150 bp sequence which separates the Fnr1 and NarL2 boxes. Based on the effects of selective 5' deletions and site-directed modifications, Fnr-dependent expression was dependent only on the Fnr1 box and nitrate stimulation was dependent on the presence of the NarL2 box. In the absence of the NarL2 box, the NarL1 box did not promote stimulation by nitrate. The Fnr2 box was not required for anaerobic induction of expression but its modification appeared to reduce the level of stimulation by nitrate.


In vivo generation of linear plasmids with addition of telomeric sequences by Histoplasma capsulatum. Histoplasma capsulatum is a dimorphic pathogenic fungus that is a major cause of respiratory and systemic mycosis. We previously developed a transformation system for Histoplasma and demonstrated chromosomal integration of transforming plasmid sequences. In this study, we describe another Histoplasma mechanism for maintaining transforming DNA i.e. the generation of modified, multicopy linear plasmids carrying DNA from the transforming Escherichia coli plasmid. Under selective conditions, these linear plasmids were stable and capable of retransforming Histoplasma without further modification. In vivo modification of the transforming DNA included duplication of plasmid sequence and telomeric addition at the termini of linear DNA. Apparently Histoplasma telomerase, like that of other organisms such as humans and Tetrahymena, is able to act on non-telomeric substrates. The terminus of a Histoplasma linear plasmid was cloned and shown to contain multiple repeats of GGGTTA, the telomeric repeat unit also found in vertebrates, trypanosomes, and slime moulds.


Data collection for the evaluation of mental retardation prevention activities: the fateful forty-three. A schema for measuring the effects of prevention programs in mental retardation was presented using items that are quantifiable, accessible, and pertinent to disability outcomes. These elements relate to interventions in the prenatal, perinatal, and childhood periods. They also reflect improvements in agency systems. The items were classified as service indicators, risk indicators, and incidence/prevalence information. The list is called "The Fateful Forty-Three" because of its intimate alliance with the stakes for children now and in the future. Representative data were given for these components, as were the sources for gathering such information. The inventory was proposed to be used as a program checklist and a base for discussion and planning.


Noise or fugue: seeking the logic of child health indicators. Despite improvements in many child health indicators, several important ones, including the racial disparity in infant mortality, have not improved in recent years. A focus on dramatic but rare risk factors has distracted attention away from the primary determinants of these indicators. An analytic model to assess these indicators identifies three interacting determinates: (a) social well-being, (b) our technical capacity to reduce the risk that low social status conveys, and (c) our performance in providing access to this technical capacity. These three determinants can move independently and can, therefore, mask important trends in social status and the impact of programs and policies.


Community-based projects for the prevention of developmental disabilities. Community projects are a central feature of the Centers for Disease Control's (CDC's) Disabilities Prevention Program. Twenty-eight states now have such programs, and they use community projects to stimulate local involvement in disability prevention and as a setting to evaluate prevention needs and preventive interventions.


Effective early intervention.

Effective early intervention. Recent positive findings from three early educational intervention programs designed to prevent mental retardation as well as to improve school readiness and educational progress were summarized. Evidence was presented to show that without early intervention, children of low-IQ mothers are particularly at-risk for poor intellectual outcomes and that such children respond very favorably to intensive, systematic early intervention. In addition, new findings indicate a strong relation between the intensity of the early educational intervention and the amount of benefits realized by individual children. Further, there is new evidence that the benefits of continuous educational intervention over the first 5 years of life last at least until early adolescence. We identified six essential types of experiences that we think account for the positive outcomes and that need to be systematically included to the maximum feasible level in future early intervention programs.


Preventing secondary conditions.

Preventing secondary conditions. A secondary condition is any additional physical or mental health condition that is causally related to a primary disabling condition. Secondary conditions often increase the severity of an individual's disability and are highly preventable. The Institute of Medicine model of the disabling process, including risk factors, quality of life, and secondary conditions is presented along with a discussion of the components of a comprehensive disability prevention program.


A statewide public and professional education program on fragile X syndrome. Fragile X syndrome is reported to be the most common inherited cause of mental retardation known, but the majority of affected individuals are as yet undiagnosed. The project described in this paper was developed to increase the public and professional awareness of fragile X syndrome in the state of New Jersey. As a result there were increased efforts at diagnostic screening, provision of client and family support services, and prevention. This educational program proved to be a cost-effective method for increasing community awareness of a genetic disease on a statewide level.


An ecology of prevention for the future. The field of mental retardation is being changed by a paradigm shift in how mental retardation is conceptualized and in how services are provided. This new way of thinking is reflected in the 1992 AAMR definition of what mental retardation is (Luckasson et al., 1992). Prevention efforts must also reflect this new way of thinking, which focuses on the interaction between individuals and their environment. In this paper, the stage was set for adoption of a new vision of prevention that incorporates an ecological approach to understanding the causation of mental retardation. The articles in this symposium were reviewed and their relevance to this new vision discussed. A comprehensive, coordinated, and integrated prevention program is needed that includes new strategies addressing a variety of personal, social, and environmental risk factors and on the interactions among them.


A rapid somatic genotoxicity assay in Drosophila melanogaster using multiple mutant mutagen-sensitive (mus) strains. Mutagen-sensitive (mus) mutations in Drosophila melanogaster render developing flies hypersensitive to the lethal effects of DNA-damaging agents. In principle, multiply mutant mus strains might then serve as sensitive in vivo indicators of a wide range of mutagens and genotoxic carcinogens. As a first step to evaluate that potential we characterized interactions between mus mutations in eight double mutants containing combinations of the second chromosomal mutations mus201D1, mus205B1, mus208B1, mus210B1 and mus211B1. We found that (i) all double mutants are fully viable in the absence of mutagen exposure, (ii) mus205B1 is epistatic to any other mus mutation with respect to methyl methanesulfonate (MMS) sensitivity, and (iii) in double mutants carrying any combination of mus201D1, mus210B1 or mus211B1, MMS sensitivity is increased in a synergistic manner. Based on those results, and on mutagen cross-sensitivity data of single mutants generated in previous studies, we constructed two triple mutant mus strains for use as testers in a simple genotoxicity assay. That assay measures the survival of DNA repair-deficient mus homozygotes relative to their repair-proficient heterozygous siblings. Those two classes of fly are easily distinguished from one another by their phenotypic markers. In addition, the heterozygotes serve as a relatively mutagen-insensitive internal control in all test vials. One tester strain (mus208B1 mus210B1 mus211B2) identified 11 of 12 chemical carcinogens as genotoxic (benzo[a]pyrene, cyclophosphamide, 1,2,3,4-diepoxybutane, diethylnitrosamine, dimethylnitrosamine, ethyl methanesulfonate, formaldehyde, hexamethylphosphoramide, methyl methanesulfonate, methylnitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine). Safrole and two noncarcinogens (benzo[e]pyrene and caprolactam) tested as nongenotoxic.(ABSTRACT TRUNCATED AT 250 WORDS)


A collaborative study on the improvement of the micronucleus test in cultured human lymphocytes. A collaborative study between two laboratories has been carried out in order to investigate the reproducibility of the cytokinesis-block micronucleus assay in human lymphocytes. A modified protocol to obtain good quality slides from whole blood cultures has been developed. The spontaneous frequencies of micronuclei in binucleated lymphocytes from five male subjects were evaluated in each laboratory at two cytochalasin-B concentrations (3 and 6 micrograms/ml). Our data show that 6 micrograms/ml cytochalasin-B was more effective than 3 micrograms/ml to arrest cytokinesis in all the donors analysed. The mean frequency of micronuclei in binucleated cells was significantly lower at 6 micrograms/ml compared to 3 micrograms/ml cytochalasin-B in both laboratories. The results obtained indicate a very high concordance between both sets of data supporting the validity of the proposed protocol.


Validation studies with the micronucleus test for early spermatids of rats. A tool for detecting clastogenicity of chemicals in differentiating spermatogonia and spermatocytes. Male Wistar rats were given a single i.p. injection with different doses of ethylnitrosourea, mitomycin C, methyl methanesulphonate, cyclophosphamide or vincristine sulphate. Clastogenic damage induced in differentiating spermatogonia and spermatocytes was measured by counting micronuclei in derived early spermatids. At dose levels not resulting in cell death of resting spermatocytes, all chemicals--with the exception of vincristine--induced most of the damage in G1- and S-phase of primary spermatocytes (also called resting, pre-leptotene or pre-meiotic spermatocytes). However, at doses causing death of G1- and S-phase spermatocytes, high frequencies of micronuclei may be observed in early spermatids derived from spermatocytes treated in diplotene, diakinesis and MI and II. This is exemplified by our results with ethylnitrosourea. In our experience, the most sensitive stage of primary spermatocyte development (i.e. G1- and S-phase cells) can best be sampled 20 days after treatment. This is the optimal time interval for demonstrating the clastogenic potential of low or moderate doses of a test chemical in meiotic male germ cells of rats. The optimal sampling time for the detection of typical spindle poisons remains to be established. In general, at low or moderate dose levels, smaller or negligible amounts of chromosomal damage were induced in differentiating spermatogonia, in spermatocytes in meiotic prophase and in dividing primary or secondary spermatocytes. For obvious reasons, the micronucleus test for early spermatids cannot be used to detect clastogens which act exclusively on postmeiotic male germ cells.