Midbrain dopaminergic neurons in the mouse: Computer-assisted mapping

The dopaminergic (DA) neurons in the midbrain play a role in cognition, affect and movement. The purpose of the present study was to map and quantify the number of DA neurons in the midbrain, within the nuclei that constitute cell groups A8, A9 and A10, in the mouse. Two strains of mice were used; the C57BL/6 strain was chosen because it is commonly used in neurobiological studies, and the FVB/N strain was chosen because it is used frequently in transgenic studies. DA neurons were identified, in every fifth 20-μm-thick coronal section, using an antibody against tyrosine hydroxylase. Cell locations were entered into a computer imaging system. The FVB/N strain has 42% more midbrain DA neurons than the C57BL/6 strain; on one side of the brain there were 15,135 ± 356 neurons (mean ± S.E.M.) in the FVB/N strain, and 10,645 ± 315 neurons in the C57BL/6 strain. In both strains, approximately 11% of the neurons were located in nucleus A8 (the DA neurons in the retrorubral field), 38% in nucleus A9 (the DA neurons in the substantia nigra pars compacta, pars reticulata, and pars lateralis), and 51% in nucleus A10 (the DA neurons in midline regions such as the ventral tegmental area, central linear nucleus, and interfascicular nucleus). The number of midbrain DA cells, and their distribution within the three nuclear groups, is discussed with respect to findings in other species. © 1996 Wiley-Liss, Inc.     

Dendritic morphology and its effects on the amplitude and rise-time of synaptic signals in hippocampal CA3 pyramidal cells

Detailed anatomical analysis and compartmental modeling techniques were used to study the impact of CA3b pyramidal cell dendritic morphology and hippocampal anatomy on the amplitude and time course of dendritic synaptic signals. We have used computer-aided tracing methods to obtain accurate three-dimensional representations of 8 CA3b pyramidal cells. The average total dendritic length was 6,332 ± 1,029 μm and 5,062 ± 1,397 μm for the apical and basilar arbors, respectively. These cells also exhibited a rough symmetry in their maximal transverse and septotemporal extents (311 ± 84 μm and 269 ± 106 μm). From the calculated volume of influence (the volume of the neuropil from which the dendritic structures can receive input), it was found that these cells show a limited symmetry between their proximal apical and basilar dendrites (2.1 ± 1.2 × 10⁶ μm³ and 3.5 ± 1.1 × 10⁶ μm³, respectively). Based upon these data, we propose that the geometry of these cells can be approximated by a combination of two cones for the apical arbor and a single cone for the basilar arbor. The reconstructed cells were used to build compartmental models and investigate the extent to which the cellular anatomy determines the efficiency with which dendritic synaptic signals are transferred to the soma. We found that slow, long lasting signals show only approximately a 50% attenuation when they occur in the most distal apical dendrites. However, synaptic transients similar to those seen in fast glutamatergic transmission are transferred much less efficiently, showing up to a 95% attenuation. The relationship between the distance along the dendrites and the observed attenuation for a transient is described simply by single exponential functions with parameters of 195 and 147 μm for the apical and basilar arbors respectively. In contrast, there is no simple relation that describes how a transient is attenuated with respect to these cells' stratified inputs. This lack of a simple relationship arises from the radial orientation of the proximal apical and basilar dendrites. When combined, the anatomical and modeling data suggest that a CA3b cell can be approximated in three dimensions as the combination of three cones. The amplitude and time-course for a synaptic transient can then be predicted using two simple equations. © 1996 Wiley-Liss, Inc.     

Impact of bilateral nasal polyposis on the interoptic and interzygomatic distance

European Archives of Oto-Rhino-Laryngology - To identify and determine variations on eye distance in patients with bilateral nasal polyposis (BNP) compared to a healthy control group. This is a...     

Questioning the Quality of Maternal Caregiving During Home Visiting

Purpose: To formulate theory that will provide a meaningful framework for practice and for studies examining the efficacy of maternal-child home visits.
Design: Field research, over a period of 8 months, 1995–1996, conducted with one nurse employed by a visiting nurse association in rural New England. A total of 53 home visits were observed; documents and records were reviewed.
Methods: Data collection, field-note recording, and analysis were simultaneous. Informal interviewing and observation of the key nurse participant throughout the day focused on her intentions, actions, and meanings as she anticipated, enacted, or reflected on her visits. Client-nurse interaction and client characteristics were described and interpreted. Analysis focused on the nurse's home visits and the consequences of these visits.
Findings: The nurse conducted a specific type of home visit, identified as "child-focused," in three patterns: single, short-, and long-term. The short-term pattern, labeled "questioning the quality of maternal caregiving," is described in this article. The nurse minimally questioned and then confirmed the quality of maternal caregiving during some visits, while she seriously questioned and then continuously doubted the quality of caregiving in others. The categories of potential consequences of these visits were maternal, child, interactive, and environmental.
Conclusions: Future research should address the most effective processes for working with families when nurses doubt the quality of maternal caregiving. Field research was helpful in developing a beginning typology of maternal-child home visits, in understanding practice, and as a basis for further research examining the efficacy of maternal-child home visits.     

Persistence of Self in Advanced Alzheimer's Disease

To determine if evidence of the persistence of a sense of self or personal identity could be found in people in the middle and late stages of Alzheimer's disease. The theme of diminishing self pervades both the popular and professional literature on Alzheimer's disease.

Design:

Qualitative using conversational analysis. The purposive sample was 23 residents of two urban nursing homes in the southeastern United States who were in the middle and late stages of Alzheimer's disease. Their mean Mini-Mental State examination score was 10.65. Nineteen subjects were women, four were men in this 1993-1997 study.

Methods:

Analysis of 45 conversations lasting 30 minutes with nursing home residents with a diagnosis of probable Alzheimer's disease. Use of the first person indexical and other evidence, such as awareness and reactions to the changes that had taken place, in support of and counter to the notion of persistence of self, were sought in conversational analysis.

Findings:

Respondents used the first person indexical frequently, freely, and coherently. Evidence was also present that participants were aware of their cognitive changes. Many struggled to provide an explanation, but none mentioned Alzheimer's disease.

Conclusions:

Evidence suggests the persistence of awareness of self into the middle and late stages of Alzheimer's disease. Failure to recognize the continuing awareness of self and the human experience of the person in the middle and late stages can lead to task-oriented care and low expectations for therapeutic interventions. The bafflement noted in respondents suggests that people should be told their diagnosis and offered an explanation of what this diagnosis means.     

A Review of the Use of Nursing Diagnosis in U.S. Nurse Practice Acts

PURPOSE. To determine how many state nurse practice acts include the term or concept of "nursing diagnosis" and describe their similarities and differences.
METHODS. Investigators independently divided the practice acts of the 50 states and the District of Columbia into those that did or did not include the term "nursing diagnosis" or the word "diagnosis" within a nursing context. To describe other differences, the investigators operationally defined and independently categorized each act as trendsetting, contemporary, or traditional.
FINDINGS. Thirty-three of the 51 practice acts used the term "diagnosis" within nursing context. Of these 33, 13 were identified as trendsetters and 20 as contemporary. Seven trendsetting and 5 contemporary practice acts used the NANDA-based language or "response" when describing the "what" of nursing diagnosis. None of the trendsetting practice acts, but 8 of the contemporary acts, used the NANDA-based "individual, family or community" when describing the "who" of nursing diagnosis.
CONCLUSIONS. The language of nursing is changing. The majority of practice acts now define the practice of professional nursing as including the diagnostic act, although the manner in which they use the term varies.     

Control of the radical polymerization by 2,2,15,15‐tetramethyl‐1‐aza‐4,7,10,13‐tetraoxacyclopentadecan‐1‐oxyl and its sodium salt

The control of the radical polymerization of styrene by 2,2,15,15‐tetramethyl‐1‐aza‐4,7,10,13‐tetraoxacyclopentadecan‐1‐oxyl is reported here in bulk at 90 °C, 120 °C and in miniemulsion. Similarly, the control by its sodium complex is reported in bulk at 90 °C.

M _n vs. conversion for 3 , 3Na , and TEMPO.     

Rapid Identification and Typing of Staphylococcus aureus by PCR-Restriction Fragment Length Polymorphism Analysis of the aroA Gene

The Staphylococcus aureus aroA gene, which encodes 5-enolpyruvylshikimate-3-phosphate synthase, was used as a target for the amplification of a 1,153-bp DNA fragment by PCR with a pair of primers of 24 and 19 nucleotides. The PCR products, which were detected by agarose gel electrophoresis, were amplified from all S. aureus strains so far analyzed (reference strains and isolates from cows and sheep with mastitis, as well as 59 isolates from humans involved in four confirmed outbreaks). Hybridization with an internal 536-bp DNA fragment probe was positive for all PCR-positive samples. No PCR products were amplified when other Staphylococcus spp. or genera were analyzed by using the same pair of primers. The detection limit for S. aureus cells was 20 CFU when the cells were suspended in saline; however, the sensitivity of the PCR was lower (5 × 10² CFU) when S. aureus cells were suspended in sterilized whole milk. TaqI digestion of the PCR-generated products rendered two different restriction fragment length polymorphism patterns with the cow and sheep strains tested, and these patterns corresponded to the two different patterns obtained by antibiotic susceptibility tests. Analysis of the 59 human isolates by our easy and rapid protocol rendered results similar to those of other assays.