DNA-based prenatal diagnosis of generalized recessive dystrophic epidermolysis bullosa in six pregnancies at risk for recurrence.

Linkage analyses in generalized recessive dystrophic epidermolysis bullosa (RDEB) have implicated the type VII collagen gene (COL7A1), which encodes the major component of anchoring fibrils, and recent identification of COL7A1 mutations has provided direct evidence for COL7A1 defects underlying RDEB. In this study, COL7A1 gene analysis was used to successfully perform first-trimester prenatal diagnosis in six families at risk for recurrence of the disease. In four families, three affected with the most severe variant of RDEB (the Hallopeau-Siemens form, HS-RDEB) and one with generalized nonmutilating RDEB, prenatal diagnosis was established by linkage analysis using polymerase chain reaction-based detection of PvuII and AluI intragenic restriction fragment length polymorphism. In two other HS-RDEB families, prenatal diagnosis was carried out by direct detection of mutations in COL7A1, using denaturing gradient gel electrophoresis analysis of polymerase chain reaction-amplified genomic fragments. Analysis of fetal DNA from chorionic villus biopsy or from amniotic fluid cells showed that the fetus had inherited at least one normal COL7A1 allele in all cases. Therefore, the fetus was predicted to be unaffected in the six pregnancies, and this has been confirmed in the newborn infants. Genotype analysis with COL7A1 polymorphic markers, or direct COL7A1 mutation detection in families at risk for the disease, represent early and rapid diagnostic alternatives to second-trimester evaluation of fetal skin samples, and thus offer a major advance in prenatal diagnosis of this life-threatening form of epidermolysis bullosa.

Origins of afferents to visual suprageniculate nucleus of the cat.

Small iontophoretic ejections of horseradish peroxidase (HRP) were made from recording-multibarrel micropipette assemblies in areas of the cat's suprageniculate nucleus (SGn) that contained visually responsive neurones. The sources of afferents of the SGn were determined by locating the labeled cell bodies of neurones that were presumed to send their axons to the area of the SGn containing the light-sensitive cells. The greatest concentration of labeled cell bodies was found in the granular insular cortex and the adjacent area of agranular insula. Most cells projecting to SGn from these areas were distributed in the middle and lower laminae. A second intensely labeled region was found in stratum opticum and stratum griseum intermediate of the superior colliculus. Other areas containing labeled cells that were distributed with intermediate density included the ventral thalamic nuclear complex (basal, medial, and lateral divisions), periaqueductal gray (PAG), zona incerta, and pretectal nuclei (posterior, medial, and anterior divisions). Sparsely labeled sites included the fields of Forel, substantia nigra (pars reticulata), peri-insular cortex, superior colliculus (profundum), lateral suprasylvian cortex (posterolateral lateral suprasylvian, PLLS and posteromedial lateral suprasylvian, PMLS), anterior ectosylvian cortex, thalamic reticular complex, nucleus of the optic tract, basal part of the ventromedial hypothalamic nucleus, and the pontine reticular nucleus (oralis) and adjacent reticular formation. Together with previous electrophysiological and neuroanatomical studies, the findings suggest that the SGn provides an integrating link between limbic structures and certain modalities of sensory information.

Antimicrobial resistance in human oral and intestinal anaerobic microfloras.

In the present study we determined the resistance patterns of anaerobic bacteria from human saliva and stool specimens and investigated whether there were significant differences in resistance between outpatients and hospitalized patients, regardless of whether they had received antimicrobial agents. No bacterial strains resistant to ampicillin, piperacillin, cefoxitin, cefuroxime, imipenem, clindamycin, doxycycline, chloramphenicol, or metronidazole were isolated from the saliva samples. However, resistance to ampicillin, cefoxitin, and cefuroxime was found in strains from 70% of the fecal samples (mainly Bacteroides thetaiotaomicron, Clostridium innocuum, and Bacteroides ovatus). Resistance to both ampicillin and cefuroxime was frequently found in 19% of the isolated strains (mainly B. thetaiotaomicron, B. ovatus, and Bacteroides vulgatus). No strains that were resistant to imipenem, chloramphenicol, or metronidazole were found. Hospitalization and/or intake of antimicrobial agents was associated with an increase in the relative number of resistant anaerobic intestinal bacteria. The percentage of resistant anaerobic strains encountered, compared with the total number of anaerobic bacteria in the normal fecal microflora, was between 5.2 and 14.8%, with the lower value associated with the outpatient group. Two-thirds of the resistant strains from this group had a relative frequency of less than 1% of the total anaerobic flora, while one-third of the strains were present at a level of greater than 1%; for the hospitalized patients, two-thirds of the strains were present at a level of greater than 1%, and one-third of the strains were present at a level of less than 1% (P < 0.001). Patients who had received antimicrobial agents for 6 days or more (n=20) had an average of 1.6 resistant anaerobic strains each, while patients treated for 3 to 5 days (n = 30) had a mean number of 0.87 resistant strains each ( P < 0.05).

Amino acids as transmitters of synaptic excitation in neocortical sensory processes.

Few synaptic transmitters are known to exist that are not represented in some region or another, or at some layer or other, in the cerebral cortex of mammalian brain. The more difficult job than mere identification of which substances are present, is that of the assignment of particular functional role(s) of such substances, and as well, of determining upon exactly which element(s) of the known synaptic circuitry of neocortex, such transmitters operate. Current wisdom subscribes to the view that the excitatory amino acids, most likely L-glutamate, and L-aspartate but perhaps also L-cysteate, L-homocysteate, L-cysteine sulfinate or even (although much less likely) the endogenous dipeptide substance, N-acetyl-L-aspartyl-L-glutamate, are the major excitatory synaptic transmitters of intracortical (associational) fibres, of corticofugal projections, and, as this article will attest, of thalamocortical inputs, as well. What particular limits, or restrictions, are imposed upon these generalizations, such as whether the data pertain only to primary sensory areas or follow some other yet to be determined rule, remains to be discovered in future experiments. This paper first presents an overview of the advances in understanding that have come about during the past few decades concerning the synaptic roles of amino acid transmitters. Next, an experimental section presents new evidence based on release studies and the microiontophoretic approach, which supports the view that the amino acids, glutamate and aspartate, interact with specific, pharmacologically identified subtypes of receptors in neocortex as transmitters of synaptic excitation released from thalamic afferent terminals.

Effects of omeprazole and amoxycillin on the human oral and gastrointestinal microflora in patients with Helicobacter pylori infection.

Fourteen patients with Helicobacter pylori infection were treated with omeprazole capsules 20 mg and amoxycillin capsules 1000 mg twice daily for 14 days and 14 patients with omeprazole capsules 20 mg and placebo twice daily for 14 days. Samples from saliva, dental plaque and faeces and biopsies from antrum and corpus were analysed in order to determine the ecological changes in the normal microflora. Several microorganisms were affected by both treatment regimens. Two patients were colonised with enterobacteria in the oral cavity and stomach during the omeprazole plus amoxycillin treatment. A general increase in the number of microorganisms from gastric mucosa was observed in both treatment groups. A selection of resistant enterobacteria and an increase in beta-lactamase production was observed in the faecal samples during the omeprazole plus amoxycillin treatment. Eradication of H. pylori in the omeprazole-amoxycillin group was 50% and in the omeprazole placebo group 0% four weeks after treatment. No viable H. pylori were cultivated in the saliva, dental plaque or faecal samples. Treatment with omeprazole 20 mg and amoxycillin 1000 mg twice daily for 14 days altered the normal microflora in the oral, gastric and intestinal tract and antibiotic resistant microorganisms increased in numbers in the intestinal microflora.