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ABSTRACTThe efficiency of transmission of a pathogen within families compared with that between unrelated persons can affect both the strategies needed to control or eradicate infection and how the pathogen evolves. In industrialized countries, most cases of transmission of the gastric pathogen Helicobacter pyloriseems to be from mother to child. An alternative model, potentially applicable among the very poor in developing countries, where infection is more common and the sanitary infrastructure is often deficient, invokes frequent transmission among unrelated persons, often via environmental sources. In the present study, we compared the genotypes of H. pylorifrom members of shantytown households in Peru to better understand the transmission of H. pyloriin developing-country settings. H. pyloricultures and/or DNAs were obtained with informed consent by the string test (a minimally invasive alternative to endoscopy) from at least one child and one parent from each of 62 families. The random amplified polymorphic DNA fingerprints of 57 of 81 (70%) child-mother strain pairs did not match, nor did the diagnostic gene sequences (>1% DNA sequence difference), independent of the child's age (range, 1 to 39 years). Most strains from siblings or other paired family members were also unrelated. These results suggest that H. pyloriinfections are often community acquired in the society studied. Transmission between unrelated persons should facilitate the formation of novel recombinant genotypes by interstrain DNA transfer and selection for genotypes that are well suited for individual hosts. It also implies that the effective prevention of H. pyloriinfection and associated gastroduodenal disease will require anti-H. pylorimeasures to be applied communitywide.

ABSTRACTThe method of recovering Helicobacter pyloriDNA or viable cells absorbed on a string that a person has swallowed and that is retrieved an hour later (string test) should be a useful alternative to traditional analysis of cells or DNA obtained by endoscopy, which is invasive, uncomfortable, relatively costly, and ill-suited for community-based and pediatric studies. Here we assayed the sensitivity and validity of the string test versus conventional endoscopic biopsy for detecting and analyzing H. pyloriinfection. Forty-four people with gastric complaints were studied using both H. pyloriculture and urease gene (ureB) PCR. H. pyloriorganisms cultured from strings and biopsy specimens from the same patients were fingerprinted by the randomly amplified polymorphic DNA (RAPD) method. Biopsy sections were also hematoxylin and eosin and silver stained for H. pyloridetection. H. pyloriwas cultured from 80% of strings and detected by PCR from 91% of strings from participants whose biopsies had been H. pyloripositive by culture, PCR, and/or histology. Strains recovered from strings and biopsy specimens yielded identical or closely related RAPD profiles in each of the 24 cases tested. We conclude that the string test is a useful method for H. pylorirecovery and analysis when relatively noninvasive procedures are needed.

The method of recovering Helicobacter pylori DNA or viable cells absorbed on a string that a person has swallowed and that is retrieved an hour later (string test) should be a useful alternative to traditional analysis of cells or DNA obtained by endoscopy, which is invasive, uncomfortable, relatively costly, and ill-suited for community-based and pediatric studies. Here we assayed the sensitivity and validity of the string test versus conventional endoscopic biopsy for detecting and analyzing H. pylori infection. Forty-four people with gastric complaints were studied using both H. pylori culture and urease gene (ureB) PCR. H. pylori organisms cultured from strings and biopsy specimens from the same patients were fingerprinted by the randomly amplified polymorphic DNA (RAPD) method. Biopsy sections were also hematoxylin and eosin and silver stained for H. pylori detection. H. pylori was cultured from 80% of strings and detected by PCR from 91% of strings from participants whose biopsies had been H. pylori positive by culture, PCR, and/or histology. Strains recovered from strings and biopsy specimens yielded identical or closely related RAPD profiles in each of the 24 cases tested. We conclude that the string test is a useful method for H. pylori recovery and analysis when relatively noninvasive procedures are needed.

We have constructed reporter gene expression vectors placing the Aspergillus oryzae α-amylase cDNA and the Geotrichum candidum lipase 2 gene, under the control of the yeast gene promoters,ACT1, ADH1, PGK1, and TDH1. Expression regulated by the shorted form of the ADH1 promoter gave the highest proteins yield for cells cultured in molasses medium or flour/water mixtures. Nevertheless, the ACT1 promoter appeared as the strongest in cells growing actively with sucrose.

The doctrine of containment has been a principal element of American foreign policy for four decades. But there has been a major change in the Communist world; it is no longer a monolithic bloc. Many Marxist governments, including some Communist regimes, are not satellites or allies of the Soviets. Indeed, some are more anti-Soviet than many noncommunist states. Yugoslavia and China do not serve Soviet expansionism; their security and economic interests are closer to the West. More and more Communist regimes, faced with mounting social and economic difficulties, must turn to the West, which has so much more to offer in the economic and technological spheres. Consequently, differentiation and disintegration within the Communist alliances are inevitable. Pluralism in the Western democracies is a source of strength. In despotic countries and blocs, pluralism would sound the death knell of tyranny and of despotic centralization.The emergence of Gorbachev as a dynamic leader flexible in his relations with noncommunist countries makes the rigid containment practices of the postwar decades decidedly outdated and counterproductive. The international chessboard has become a game of movement, sensitivity, and subtlety. Consequently, the United States should use in its international relations the concept of pluralism that we have used so successfully at home. This means differentiation among the various Marxist regimes, calibrating our policy with flexibility toward each country's policy and situation affect our national interests.

Rats with either sham operations, small medial frontal cortex lesions (SMF), or large medial frontal cortex lesions (LMF) were tested in the open field, for spatial alternation and for 8-arm maze learning. The behaviors of sham-operated and SMF rats were similar on the spatial learning tasks, while the LMF group performed poorly in relation to these two groups. In contrast, the two lesion groups differed from the sham group, but not from each other, on locomotor activity in the open field. The differences in performance between the SMF and LMF groups on the spatial learning measures suggest that medial frontal cortex lesion size and locus may be important factors underlying the variable results of previous studies evaluating spatially-oriented behaviors of rats with varying degrees of medial frontal cortex damage.

Despite the continuing improvements in computeraided design (CAD) systems and improvements in geometric modeling, most CAD systems are used as advanced drafting and drawing management tools by structural designers. A computer model of a structural design usually is generated by creating a detailed geometric model of the primitive components of the design and then attaching attributes, such as physical properties and loading conditions, to the various geometric components to reveal the structural characteristics of those components. Thisbottom-up approach has been inherited from early drafting techniques and contrasts sharply with a structural designer's natural way of thinking and reasoning about the design. Geometric features, on the other hand, provide high-level abstractions of design information and can be tailored to a designer's specific engineering needs. In this paper the advantages of using feature-based techniques in structural CAD systems are discussed. These techniques provide better modeling primitives for users and superior data models for CAD systems for reasoning about the geometry, topology, and engineering properties of a structure.

In order to trade off required functionality with manufacturing, cost, and other life-cycle considerations, it is necessary to evaluate designs in these secondary view-points. Representations of mechanical components designed with design features must be converted into representations containing relevant secondary viewpoint features. When describing a design verbally, designers often use languages of design features. In other viewpoints, different languages of viewpoint-specific features are used. Thus, translation capability between viewpoint languages is needed to convert from one representation to another. The approach taken here is to use formal graph grammars to define the feature-based design of thin-walled components and the secondary feature languages. Features are defined by graphs that explicitly represent the feature, its geometric entities, and their connectivity. Components are built up by combining feature graphs based on designer specified feature connectivity. To convert from the design to a secondary viewpoint, a three-step process is used where the last step is parsing by a grammar from the secondary viewpoint. To illustrate the conversion process, a converter for tool cost evaluation in injection molding and die casting is developed and applied to an example component.

Wound-derived trophic factors released by the injured brain are thought to reach a peak 1–2 weeks after injury. It has been proposed that such factors can promote the survival, growth and functional capacity of embryonic tissue grafts. To test the generality of this hypothesis, control rats and rats with aspirative fimbria-fornix lesions were compared with 5 groups of rats with lesions and septal grafts implanted either in the same session as the lesion or after delays from 10 days to 9 months. Animals were assessed 3 months post-transplantation on an operant differential reinforcement of low rates (DRL) task and on a test of spontaneous locomotor activity. Lesions produced impairments on all measures of DRL performance. Two graft groups showed amelioration of the DRL deficits, one graft group was unchanged, and the deficits were exacerbated in two others. There was no clear relationship between lesion–graft interval and recovery. An inverse relationship was seen, however, between recovery and the developmental age of the donor tissue. In contrast, significant recovery from lesion-induced hyperactivity was observed in the two graft groups with tissue derived from the oldest embryos. There were no clear relationships between recovery on either test, lesion–graft interval, and AChE-positive reinnervation of the host brain. The results provide further evidence that septal grafts can reverse behavioural deficits induced by fimbria-fornix lesions under some conditions, but suggest that the timing of graft surgery may not be as important a factor as donor age in this model system.

Four groups of rats with bilateral lesions of somatosensory cortex and one of animals sustaining only sham operations were tested for retention of a difficult tactile discrimination. Two of the lesion groups had serial ablations, in one case with interoperative testing, and two had one-stage lesions. Bilateral ablations of somatosensory cortex severely retarded retention in all lesion groups relative to the control group and serial and one-stage groups did not differ from each other. The sham operated rats then experienced lesions of cortex anterior and posterior to the somatosensory areas. These lesions only marginally affected retention. Somatosensory cortex then was ablated and severe performance decrements were seen. Removal of additional neocortex in animals that previously had relearned the discrimination after somatosensory cortex lesions also resulted in very poor retention. These data demonstrate the importance of the somatosensory cortex in mediating tactile discriminations and suggest that non-somatosensory cortex may play a role in recovery after somatosensory cortical lesions.

Five groups of rats with bilateral lesions of the somatosensory cortex and one of animals sustaining only sham operations were tested for retention of a rough-smooth discrimination. Two of the lesion groups had sequential unilateral ablations, in one case with interoperative testing, and three groups had one-stage bilateral lesions. The two groups of animals with serial lesions did not differ from each other or from sham operates in relearning the task. Rats with one-stage lesions and preoperative overtraining also performed well, but the other one-stage groups showed deficits relative to control and serial lesion groups. In the second experiment the sham operated rats from Experiment 1 experienced lesions anterior and posterior to the somatosensory zones. These lesions did not affect retention. Somatosensory cortex then was ablated in one operation and severe performance decrements were seen. Removal of additional neocortex in a sample of animals that had relearned the discrimination after one-stage somatosensory cortex lesions (Exp. 1) also affected retention. In contrast, retention was not impaired on some of the measures in those animals that originally had two-stage ablations. The findings from these two experiments show that some ablation effects can be circumvented with overtraining or serial lesion techniques. The data also indicate that non-somatosensory cortex may play a role in recovery after somatic cortex lesions, but that the substrates underlying recovery might, not be the same after one-stage and two-stage ablations.

In order to trade off required functionality with manufacturing, cost, and other life-cycle considerations, it is necessary to evaluate designs in these secondary view-points. Representations of mechanical components designed with design features must be converted into representations containing relevant secondary viewpoint features. When describing a design verbally, designers often use languages of design features. In other viewpoints, different languages of viewpoint-specific features are used. Thus, translation capability between viewpoint languages is needed to convert from one representation to another. The approach taken here is to use formal graph grammars to define the feature-based design of thin-walled components and the secondary feature languages. Features are defined by graphs that explicitly represent the feature, its geometric entities, and their connectivity. Components are built up by combining feature graphs based on designer specified feature connectivity. To convert from the design to a secondary viewpoint, a three-step process is used where the last step is parsing by a grammar from the secondary viewpoint. To illustrate the conversion process, a converter for tool cost evaluation in injection molding and die casting is developed and applied to an example component.

Rats with prefrontal cortex (PFC) lesions or sham operations were tested for acquisition and reversal learning with tactile-visual stimuli. PFC rats performed extremely poorly during acquisition and also differed from control rats in reversal learning. Both higher-order processing and subtle motoric dysfunctions may have combined to account for the marked effects of these cortex lesions.

Rats with bilateral lesions of the medial frontal cortex were tested in a T-maze for the ability to learn a position habit and to make four reversals of it. Rats with medial frontal cortical lesions showed deficits in reversal learning. In addition, they were found to be hyperactive in an open field. Treatment with the dihydropyridine calcium channel antagonist, nimodipine, did not reduce these behavioral deficits.

We reviewed 194 revision arthroplasties of the hip and knee performed over a ten-year period. The results of intraoperative Gram staining were available in 169 (87%). Thirty-two were found to be infected (11 hips and 21 knees) and 137 had no evidence of infection.Intraoperative Gram staining was negative in all 169 cases. The method therefore had a sensitivity of 0% for detecting infection. We conclude that the absence of organisms on intraoperative Gram staining during revision arthroplasty does not confirm the absence of infection.