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Biomedical subjects

L M Herman

Publications and source records attributed to L M Herman.

At least 19 recordsLinked to original sources
PubMed2000

Effect of amphetamine-induced dopamine release on radiotracer binding to D1 and D2 receptors in rat brain striatal slices.

The in vivo binding of positron emission tomography (PET) and single photon emission computer tomography (SPECT) radiotracers to dopamine D2 receptors in the striatum can be influenced by competition with endogenous dopamine. The present study was undertaken to determine if a similar inhibition of radiotracer binding to dopamine receptors could be observed following pharmacologically-evoked dopamine release in rat brain striatal slices. Striatal slices were incubated in a large volume of oxygenated Krebs saline and exposed to amphetamine or methamphetamine to evoke dopamine release within the slice. Amphetamine and methamphetamine, at concentrations up to 30 microM, reduced [3H]raclopride binding in the slices by 77% and 86%, respectively, with 50% inhibition at 1.6 microM amphetamine or 3.0 microM methamphetamine. Neither drug produced a significant effect on binding of [3H]SCH 23390 in the slices. This suggests that dopamine was able to interfere with radiotracer binding to D2 but not D1 receptors. The dopamine uptake blockers, cocaine and methylphenidate, had relatively little effect by themselves on [3H]raclopride binding but, by inhibiting amphetamine-induced dopamine release, significantly reduced inhibition of [3H]raclopride binding by a low (3 microM) amphetamine concentration. At a higher (30 microM) amphetamine concentration the inhibition of [3H]raclopride binding was not antagonized by uptake blockers and data obtained from homogenate binding experiments indicated a direct displacement of [3H]raclopride binding by amphetamine at this concentration. In conclusion the data obtained in the present study demonstrate that the effects of amphetamine on striatal radiotracer accumulation observed in PET and SPECT can also be observed in brain slices in vitro and, at least at low amphetamine concentrations, are mediated by competition with released dopamine.

Amphetamine↗
PubMed2000

Differentiation of Brucella species by random amplified polymorphic DNA analysis.

Random amplification of polymorphic DNA (RAPD) was used for discrimination between 46 Brucella strains and 14 representatives of the alpha-2 and alpha-1 subgroups of Proteobacteria. To evaluate a relatively quick and exact method for Brucella identification, the authors specified the most suitable conditions for RAPD amplification of Brucella DNA with two 10-mer primers, containing lower and higher percentages of G and C. The software package PHYLIP 3.1 was used for cluster analysis of the RAPD fingerprints. The optimization of RAPD conditions resulted in PCR mixes suitable for reliable typing of Brucellae. The distance-based methods (Fitch-Margoliash, UPGMA and Neighbour-joining) gave clear discrimination between Brucella species. The constructed dendrograms put Br. canis and Br. suis bv. 1 in the same cluster and differentiated Brucella strains according to their host preferences. RAPD can be useful method to distinguish related bacterial species, and under strictly established conditions the reaction appears to be a simple, quick and sensitive technique for the epidemiological investigation of brucellosis.

Brucella↗
PubMed1999

Dolphins (Tursiops truncatus) comprehend the referential character of the human pointing gesture.

The authors tested a dolphin's (Tursiops truncatus) understanding of human manual pointing gestures to 3 distal objects located to the left of, to the right of, or behind the dolphin. The human referred to an object through a direct point (Pd), a cross-body point (Px), or a familiar symbolic gesture (S). In Experiment 1, the dolphin responded correctly to 80% of Pds toward laterally placed objects but to only 40% of Pds to the object behind. Responding to objects behind improved to 88% in Experiment 2 after exaggerated pointing was briefly instituted. Spontaneous comprehension of Pxs also was demonstrated. In Experiment 3, the human produced a sequence of 2 Pds, 2 Pxs, 2 Ss, or all 2-way combinations of these 3 to direct the dolphin to take the object referenced second to the object referenced first. Accuracy ranged from 68% to 77% correct (chance = 17%). These results established that the dolphin understood the referential character of the human manual pointing gesture.

Animal Communication↗
PubMed1998

Seeing through sound: dolphins (Tursiops truncatus) perceive the spatial structure of objects through echolocation.

Experiment 1 tested a dolphin (Tursiops truncatus) for cross-modal recognition of 25 unique pairings of 8 familiar, complexly shaped objects, using the senses of echolocation and vision. Cross-modal recognition was errorless or nearly so for 24 of the 25 pairings under both visual to echoic matching (V-E) and echoic to visual matching (E-V). First-trial recognition occurred for 20 pairings under V-E and for 24 under E-V. Echoic decision time under V-E averaged only 1.88 s. Experiment 2 tested 4 new pairs of objects for 24 trials of V-E and 24 trials of E-V without any prior exposure of these objects. Two pairs yielded performance significantly above chance in both V-E and E-V. Also, the dolphin matched correctly on 7 of 8 1st trials with these pairs. The results support a capacity for direct echoic perception of object shape by this species and demonstrate that prior object exposure is not required for spontaneous cross-modal recognition.

Animals↗
PubMed1997

Identification and detection of Bacillus sporothermodurans spores in 1, 10, and 100 milliliters of raw milk by PCR.

A PCR method was developed to detect spores of Bacillus sporothermodurans in 1, 10, and 100 ml of raw milk. Two primers were derived from a unique sequence after subtractive hybridization of B. sporothermodurans DNA with DNA of MB 397, a not yet identified spore-forming bacterium isolated from raw milk, closely related to B. sporothermodurans. Specific identification was proven on a large collection of Bacillus strains and on strains from relevant taxa. The detection of B. sporothermodurans in raw milk is based on activation, germination, and outgrowth of the spores, followed by PCR identification. Spores from 10 and 100 ml were concentrated by centrifugation after chemical extraction of the milk components. The total test takes 28 h. The detection limits are 9, 0.4, and 0.22 CFU/ml for 1, 10, and 100 ml, respectively.

Animals↗
PubMed1996

Direct detection of Brucella spp. in raw milk by PCR and reverse hybridization with 16S-23S rRNA spacer probes.

The 16S-23S rRNA spacer regions of Brucella abortus, B. melitensis, and B. suis were cloned and subcloned after PCR amplification. Sequence analysis of the inserts revealed a spacer of about 800 bp with very high ( > 99%) homology among the three species examined. Two genus-specific primer pairs, BRU-P5-BRU-P8 and BRU-P6-BRU-P7, that could be used in a nested PCR format and three genus-specific DNA probes, BRU-ICG2, BRU-ICG3, and BRU-ICG4, were deduced from this spacer. The specificity and sensitivity of both primer sets and probes were examined by testing them against a collection of 18 Brucella strains and 56 strains from other relevant taxa by using PCR and the Line Probe Assay (LiPA), respectively. A method for direct detection of Brucella spp. in 1 ml of raw milk was developed on the basis of enzymatic treatment of the milk components and subsequent PCR and LiPA hybridization. After a single PCR, sensitivities of 2.8 x 10(5) and 2.8 x 10(4) CFU/ml were obtained for detection by agarose gel electrophoresis and LiPA, respectively. Nested PCR yielded a sensitivity of 2.8 x 10(2) CFU/ml for both methods.

Animals↗
PubMed1995

Simultaneous detection of Listeria spp. and Listeria monocytogenes by reverse hybridization with 16S-23S rRNA spacer probes.

Enzymatic amplification results showed that Listeria species have at least two 16S-23S rRNA spacer regions of different lengths. These spacer regions of L. monocytogenes, L. ivanovii and L. seeligeri were cloned after enzymatic amplification. Sequence analysis of the inserts revealed two spacers of 245-246 bp and 496-498 bp, respectively, of which the latter included tRNA(Ala) and tRNA(Ile) genes. One Listeria spp.-specific probe, LIS-ICG4, was deduced from the 245-bp spacer and a L. monocytogenes-specific probe, LMO-ICG5, was inferred from the 496-bp spacer. The specificity of both probes was tested in a reverse hybridization assay (Line Probe Assay, LiPA). Both LIS-ICG4 and LMO-ICG5 proved to be highly specific when hybridized to a large collection of Listeria strains and strains from other relevant taxa. The LiPA test herein described for the simultaneous detection of Listeria spp. and L. monocytogenes can be expanded to detect other foodborne pathogens.

Base Sequence↗
PubMed1995

Sensory integration in the bottlenosed dolphin: immediate recognition of complex shapes across the senses of echolocation and vision.

In matching-to-sample tests, a bottlenosed dolphin (Tursiops truncatus) was found capable of immediately recognizing a variety of complexly shaped objects both within the senses of vision or echolocation and, also, across these two senses. The immediacy of recognition indicated that shape information registers directly in the dolphin's perception of objects through either vision or echolocation, and that these percepts are readily shared or integrated across the senses. Accuracy of intersensory recognition was nearly errorless regardless of whether the sample objects were presented to the echolocation sense and the alternatives to the visual sense (E-V matching) or the reverse, with samples presented to the visual sense and alternatives to the echolocation sense (V-E matching). Furthermore, during V-E matching, the dolphin was equally facile at recognition whether the sample objects exposed to vision were "live," presented in air in the real world, or were images displayed on a television screen placed behind an underwater window. Overall, the results suggested that what a dolphin "sees" through echolocation is functionally similar to what it sees through vision.

Animals↗
PubMed1995

A direct PCR detection method for Clostridium tyrobutyricum spores in up to 100 milliliters of raw milk.

A direct detection method for Clostridium tyrobutyricum spores in up to 100 ml of raw milk is presented. The bacterial spores are concentrated by centrifugation after chemical extraction of the milk components. The vegetative cells are selectively lysed, and their DNA is digested and washed away. Afterwards, the DNA is liberated from the spores by microwave treatment. For the identification of the C. tyrobutyricum DNA, a two-step PCR method with two nested pairs of primers is used. The primers were derived from the 16S-23S rRNA spacer region of C. tyrobutyricum, and the specificity of each of them for C. tyrobutyricum is demonstrated. The detection limit can be estimated to be between 3 and 30 spores in 100 ml of raw milk.

Animals↗
PubMed1994

meta-iodobenzylguanidine uptake in the hypertensive-diabetic rat heart: a marker for myocardial dysfunction?

The purpose of this study was to investigate the cardiac adrenergic neuronal changes induced by diabetes and hypertension by using an analogue of norepinephrine, meta-iodobenzylguanidine (MIBG), and to compare these changes with the contractile state of ventricular papillary muscle. The tissue concentration of norepinephrine in the cardiac apex was also measured for direct comparison with [123I]MIBG uptake. One week following the induction of diabetes by streptozotocin injection (55 mg/kg, i.v.), male Sprague-Dawley rats were given subcutaneous injections of a hypertension-inducing agent, deoxycorticosterone acetate (DOCA, 25 mg/kg), or DOCA vehicle twice weekly for 3, 6, 9, or 12 weeks. At the end of each time point, the animals were injected intravenously (15 mCi/mg; 1 Ci = 37 GBq) with [123I]MIBG. The results showed a progressive decrease in MIBG uptake into the hearts of diabetic, hypertensive, and diabetic-hypertensive rats during the 12-week observation period, compared with the control group. However, length-tension papillary muscle studies at 12 weeks indicated that only the diabetic group had a diminished performance compared with control. Furthermore, an inverse relationship was observed between MIBG uptake and norepinephrine levels in the cardiac apex of the diabetic and diabetic-hypertensive groups. Therefore, we concluded that either MIBG does not provide an accurate indication of adrenergic integrity or that there is no relationship between sympathetic activity and myocardial function at the time points measured. MIBG did not prove to be a useful marker for myocardial dysfunction in diabetic rats.

3-Iodobenzylguanidine↗
PubMed1993

Responses to anomalous gestural sequences by a language-trained dolphin: evidence for processing of semantic relations and syntactic information.

This study examined the responses of a bottlenosed dolphin (Tursiops truncatus) to "normal" (semantically and syntactically correct) sequences of gestures and to anomalous sequences given within an artificial gestural language highly familiar to the animal. Anomalous sequences violated the semantic rules or syntactic constraints of the language. The dolphin discriminated anomalous from normal sequences in that rejections (refusals to respond) occurred to some anomalous sequences but never to normal sequences. Rejections rarely occurred, however, if the anomalous sequence contained a subset of gestures that would comprise a normal unit if joined together. Such units were typically perceived by the dolphin and responded to even if they consisted of gestures that were not sequentially adjacent. All semantic elements of a sequence were processed by the dolphin in relation to other elements before the dolphin organized its final response. The results show the importance of both semantic properties and semantic relations of the referents of the gestures and of syntactic (ordering) constraints in the dolphin's interpretations of the anomalies.

Animal Communication↗
PubMed1990

Bottlenosed dolphin and human recognition of veridical and degraded video displays of an artificial gestural language.

2 bottlenosed dolphins proficient in interpreting gesture language signs viewed veridical and degraded gestures via TV without explicit training. In Exp. 1, dolphins immediately understood most gestures: Performance was high throughout degradations successively obscuring the head, torso, arms, and fingers, though deficits occurred for gestures degraded to a point-light display (PLD) of the signer's hands. In Exp. 2, humans of varying gestural fluency saw the PLD and veridical gestures from Exp. 1. Again, performance declined in the PLD condition. Though the dolphin recognized gestures as accurately as fluent humans, effects of the gesture's formational properties were not identical for humans and dolphin. Results suggest that the dolphin uses a network of semantic and gestural representations, that bottom-up processing predominates when the dolphin's short-term memory is taxed, and that recognition is affected by variables germane to grammatical category, short-term memory, and visual perception.

Animal Communication↗
PubMed1989

Different 3' end regions strongly influence the level of gene expression in plant cells.

We have investigated the functional role of a 3' end region on the expression of a reporter gene in plant cells. In stably transformed plants, expression of the reporter gene without a plant gene 3' end is variable and depends on the fortuitous presence of polyadenylation signals in the downstream sequences. When the reporter gene is flanked by pBR322 DNA, 3'-processing and polyadenylation occurs at (a) cryptic site(s) within these vector sequences. Using a transient gene expression system, we present a deletion analysis of the 3' end of the octopine synthase gene showing that the most proximal polyadenylation signal per se is not sufficient to ensure expression but that a downstream (G)T-rich sequence is also required. Optimal expression of the fusion gene requires more than 98 base pairs and at most 142 base pairs downstream from the most distal polyadenylation site. We analyzed the expression of chimeric genes with 3' end sequences originating from different plant genes. In the transient expression assay, all constructs direct similar neomycin phosphotransferase II activities. However, in stably transformed tissue, the gene constructs displayed characteristic expression levels which varied as much as 60-fold. This result suggests a role for 3' end sequences in post-transcriptional processes such as efficiency of 3'-processing and/or mRNA stability.

Amino Acid Oxidoreductases↗
PubMed1987

Immunohistochemical localization of substance P and enkephalin in the nucleus tractus solitarii of the rhesus monkey, Macaca mulatta.

The nucleus tractus solitarii in the monkey Macaca mulatta was found to have several subdivisions based upon cytoarchitectonics and immunohistochemistry. Subdivisions that could be identified included commissural, medial, parvicellular, dorsolateral, ventrolateral, intermediate, and interstitial. Substance P and enkephalin immunoreactivity was localized within discrete regions of the nucleus tractus solitarii, by means of the peroxidase-antiperoxidase technique. Substance P immunoreactivity occurred most frequently in the interstitial subdivision of the nucleus tractus solitarii. Moderate accumulations of substance P immunoreactivity were present in the commissural, medial, parvicellular, dorsolateral, and intermediate subdivisions, but very little was present in the ventrolateral subdivision. Enkephalin immunoreactivity followed the staining patterns of substance P; however, the amounts of enkephalin immunoreactivity were less than amounts for substance P. Following colchicine treatment, large numbers of enkephalin-immunoreactive neurons were distributed throughout all subdivisions, many being located in the parvicellular and medial subdivisions. The few substance P-immunoreactive neurons found were restricted to the parvicellular subdivision. The distribution of substance P and enkephalin immunoreactivity in M. mulatta is very similar to that described in the cat and rat. In addition, the extensive overlap of the distribution of these two putative neurotransmitters provides morphological evidence for their possible participation in the autonomic regulation within the nucleus tractus solitarii.

Animals↗
PubMed1986

Status of stroke patients: a community assessment.

The identification of norms relating to the status of stroke patients is significant to community plans to provide contemporary health services for stroke patients. This two-phase research study assessed the status of stroke patients for a large metropolitan area. The first phase of research was a retrospective hospital record review conducted on 1,665 subjects admitted to 13 Cincinnati hospitals with the primary diagnosis of stroke. This study showed that the Cincinnati outcomes were consistent with the outcomes demonstrated in the literature. The most typical stroke patient was a 71-year-old woman with right hemiplegia, who was living at home with another adult after spending 17.5 days in the acute care hospital. The behavioral functional levels of 105 disabled stroke patients were assessed in the second phase, using the Level of Rehabilitation Scale. Subjects were analyzed in five functional areas to determine their level of independent living. Demographic data were used to analyze the findings in comparisons. In general, stroke patients function higher in activities of daily living than they do in social interactions. Stroke patients living with another adult demonstrated a lower degree of functioning in activities of daily living than those who lived alone, but scored higher in social interactions.

Activities of Daily Living↗
PubMed1986

Isolation of tobacco DNA segments with plant promoter activity.

We constructed a promoter probe vector, pGVL120, to isolate plant DNA segments with promoter activity in tobacco. Plant nuclear DNA Sau3A fragments were inserted in front of the npt-II sequence, and a mixture of recombinant plasmids was mobilized to Agrobacterium sp. and used to transform tobacco protoplasts. By kanamycin selection, transformed plant cell lines containing NPT-II T-DNAs were isolated. Eight of these cell lines were regenerated and analyzed for the levels of NPT-II activity in stem, root, midrib, and leaf. These levels demonstrated novel regulation patterns in each isolate. One cell line, T20, was analyzed in detail and found to contain four different T-DNAs. One of the recloned T-DNAs, T20-2, contains an insert of 401 base pairs in front of the NPT-II sequence, and by reintroducing this T-DNA into plant cells we could demonstrate that this insert provides a promoter sequence. The NPT-II enzyme activity under the control of the P20 promoter is especially high in stem and root, but low in leaf and callus, both in the originally isolated T20 plant and in independently isolated transformants with the T20-2 T-DNA.

Base Sequence↗