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Biomedical subjects

L Manning

Publications and source records attributed to L Manning.

At least 19 recordsLinked to original sources
PubMed2006

[Selective memory impairment for public events associated with accelerated forgetting in a patient with left temporal lobe epilepsy].

BACKGROUND: Memory for the past has been much less explored than anterograde memory in temporal lobe epilepsy. No data are available about the course after surgical treatment. Moreover, case-reports showing isolated memory deficit for publics events with preserved autobiographical memory are notorious for their paucity. METHODS: We report the case of a patient with a left hippocampal lesion associated with intractable temporal lobe epilepsy. Comprehensive neuropsychological assessments were carried out before and after temporal lobectomy, stressing particularly memory for the past by means of standardised and tailor-made tests. RESULTS: The patient exhibited preserved memory for autobiographical events and facts but impaired scores on several public event tests, in the context of preserved general abilities. Furthermore, we found an accelerated forgetting rate for verbal and non verbal material. CONCLUSION: Our findings suggest that the patient's impaired long-term consolidation might have contributed to the impaired performance on public event memory tests. We discuss the specific features of new events processing that may contribute to its increased vulnerability relative to autobiographical memory, in the event of accelerated forgetting.

Brain↗
PubMed2005

Anterior and non-anterior ruptured aneurysms: memory and frontal lobe function performance following coiling.

Our aim was to compare memory and frontal function performance between two groups of patients treated with Guglielmi detachable coil (GDC) following intracranial ruptured aneurysm. The subgroups drawn following the localization of the aneurysm consisted of 19 patients presenting with anterior communicating artery aneurysms and 16 patients exhibiting middle cerebral artery and posterior communicating artery aneurysms. The 35 patients and 35 normal controls were administered extensive neuropsychological assessment. Additionally, a scale of qualitative changes of mood was presented to the patients and patients' relatives. The patients showed a better general performance on memory compared with the executive function performance, which was similarly impaired in both groups. We suggest that executive functions are more vulnerable to differently located lesions than memory functions.

Adult↗
PubMed2004

Improving tapping mode atomic force microscopy with piezoelectric cantilevers.

This article summarizes improvements to the speed, simplicity and versatility of tapping mode atomic force microscopy (AFM). Improvements are enabled by a piezoelectric microcantilever with a sharp silicon tip and a thin, low-stress zinc oxide (ZnO) film to both actuate and sense deflection. First, we demonstrate self-sensing tapping mode without laser detection. Similar previous work has been limited by unoptimized probe tips, cantilever thicknesses, and stress in the piezoelectric films. Tests indicate self-sensing amplitude resolution is as good or better than optical detection, with double the sensitivity, using the same type of cantilever. Second, we demonstrate self-oscillating tapping mode AFM. The cantilever's integrated piezoelectric film serves as the frequency-determining component of an oscillator circuit. The circuit oscillates the cantilever near its resonant frequency by applying positive feedback to the film. We present images and force-distance curves using both self-sensing and self-oscillating techniques. Finally, high-speed tapping mode imaging in liquid, where electric components of the cantilever require insulation, is demonstrated. Three cantilever coating schemes are tested. The insulated microactuator is used to simultaneously vibrate and actuate the cantilever over topographical features. Preliminary images in water and saline are presented, including one taken at 75.5 microm/s-a threefold improvement in bandwidth versus conventional piezotube actuators.

Journal Article↗
PubMed2000

The tumour-suppressor genes lgl and dlg regulate basal protein targeting in Drosophila neuroblasts.

Drosophila neuroblasts are a model system for studying asymmetric cell division: they divide unequally to produce an apical neuroblast and a basal ganglion mother cell that differ in size, mitotic activity and developmental potential. During neuroblast mitosis, an apical protein complex orients the mitotic spindle and targets determinants of cell fate to the basal cortex, but the mechanism of each process is unknown. Here we show that the tumour-suppressor genes lethal giant larvae (lgl) and discs large (dlg) regulate basal protein targeting, but not apical complex formation or spindle orientation, in both embryonic and larval neuroblasts. Dlg protein is apically enriched and is required for maintaining cortical localization of Lgl protein. Basal protein targeting requires microfilament and myosin function, yet the lgl phenotype is strongly suppressed by reducing levels of myosin II. We conclude that Dlg and Lgl promote, and myosin II inhibits, actomyosin-dependent basal protein targeting in neuroblasts.

Amino Acid Sequence↗
PubMed2000

Unplanned admissions following outpatient otologic surgery: the University of Arkansas experience.

We analyzed the outpatient otologic surgery experience at our institution to identify those factors that are associated with a high risk of postoperative complications that require an unplanned hospital admission. We found that among a group of 662 patients who underwent group II otologic procedures (i.e., tympanoplasty with or without mastoidectomy, stapedotomy, and middle ear exploration), the overall admission rate was 4.7%, of which 3.9% were unplanned. A significantly larger percentage of children were admitted than adults (5.7 vs. 2.3%), primarily for nausea and vomiting. Three factors were significantly associated with unplanned admissions: the type of surgery (tympanomastoidectomy with ossicular reconstruction), the duration of general anesthesia (> 2 hr), and asthma as a coexisting condition. The choice of antiemetic administered (ondansetron or droperidol) and the specific agents used for general anesthesia did not appear to have any significant impact on unplanned admissions. We recommend that the three predisposing factors be taken into consideration when formulating the treatment plan. Scheduling an inpatient procedure for patients who have risk factors for complications requiring hospitalization would avoid the extra costs and stress associated with unplanned admissions.

Adult↗
PubMed1999

Prospero distinguishes sibling cell fate without asymmetric localization in the Drosophila adult external sense organ lineage.

The adult external sense organ precursor (SOP) lineage is a model system for studying asymmetric cell division. Adult SOPs divide asymmetrically to produce IIa and IIb daughter cells; IIa generates the external socket (tormogen) and hair (trichogen) cells, while IIb generates the internal neuron and sheath (thecogen) cells. Here we investigate the expression and function of prospero in the adult SOP lineage. Although Prospero is asymmetrically localized in embryonic SOP lineage, this is not observed in the adult SOP lineage: Prospero is first detected in the IIb nucleus and, during IIb division, it is cytoplasmic and inherited by both neuron and sheath cells. Subsequently, Prospero is downregulated in the neuron but maintained in the sheath cell. Loss of prospero function leads to 'double bristle' sense organs (reflecting a IIb-to-IIa transformation) or 'single bristle' sense organs with abnormal neuronal differentiation (reflecting defective IIb development). Conversely, ectopic prospero expression results in duplicate neurons and sheath cells and a complete absence of hair/socket cells (reflecting a IIa-to-IIb transformation). We conclude that (1) despite the absence of asymmetric protein localization, prospero expression is restricted to the IIb cell but not its IIa sibling, (2) prospero promotes IIb cell fate and inhibits IIa cell fate, and (3) prospero is required for proper axon and dendrite morphology of the neuron derived from the IIb cell. Thus, prospero plays a fundamental role in establishing binary IIa/IIb sibling cell fates without being asymmetrically localized during SOP division. Finally, in contrast to previous studies, we find that the IIb cell divides prior to the IIa cell in the SOP lineage.

Animals↗
PubMed1998

Use of intravascular ultrasound improves long-term clinical outcome in the endovascular management of atherosclerotic aortoiliac occlusive disease.

PURPOSE: This study was undertaken to determine whether the use of intravascular ultrasound (IVUS) during balloon angioplasty and stenting of atherosclerotic aortoiliac occlusive lesions improved long-term clinical outcome. IVUS has been previously shown to be more accurate than arteriography in evaluating the deployment of stents in both peripheral and coronary arteries. Incomplete stent deployment has been anecdotally identified as a cause of restenosis or occlusion of a treated lesion. To our knowledge, there have been no previous studies that demonstrate whether the use of IVUS will affect the long-term patency rate of stented arterial lesions. METHODS: Between March 1992 and October 1995, 52 patients with symptomatic aortoiliac occlusive disease underwent balloon angioplasty and stenting of their lesions. We retrospectively reviewed these cases to determine whether the use of IVUS influenced the long-term patency rate of these interventions. Follow-up ranged from 1 to 4 years with a mean of 28 months. RESULTS: Fifty-two patients had confirmation of adequate stent deployment by arteriography. IVUS was used in conjunction with arteriography in 36 patients to evaluate stent deployment. Patients in the IVUS-assisted group were slightly younger than those patients who were evaluated solely by arteriography (p < 0.01). No statistical differences were noted between the two groups with respect to coronary artery disease, diabetes mellitus, obstructive pulmonary disease, hypertension, or obesity. Length of hospital stay, number of stents used, and preoperative ankle brachial indexes were comparable in both groups. In the arteriography plus IVUS group, 40% of patients had underdeployed stents by IVUS evaluation, though they appeared adequately expanded by arteriography. No restenoses or occlusions were seen in the arteriography plus IVUS group. Restenosis or occlusion of the stented lesion occurred in 25% of patients evaluated by arteriography alone (p < 0.01). These failures were treated by either thrombolysis or catheter thrombectomy and were then evaluated with IVUS. All were found to have underdeployed stents. Subsequent treatment consisted of adequate redeployment of existing stents using IVUS criteria. These salvaged reconstructions have continued to remain patent. CONCLUSIONS: The use of IVUS may be the best means for assessing adequacy of arterial stent deployment. Our study suggests that the use of IVUS improves the long-term clinical outcome of balloon angioplasty and stented aortoiliac occlusive lesions.

Adult↗
PubMed1997

IL-7 overexpression in transgenic mouse keratinocytes causes a lymphoproliferative skin disease dominated by intermediate TCR cells: evidence for a hierarchy in IL-7 responsiveness among cutaneous T cells.

IL-7 is a keratinocyte-derived lymphocyte growth factor critical for the development of gammadelta T cells including murine dendritic epidermal T cells (DETC). We derived transgenic mice that overexpress IL-7 in basal keratinocytes under the control of the human K14 promoter. These K14/IL-7 mice develop dermal and epidermal T cell infiltrates associated with alopecia. This lymphoproliferative skin disease is substantially more severe in mice homozygous for the K14/IL-7 transgene. Conventional DETC expressing a Vgamma5 Vdelta1 TCR are rare or absent among the cutaneous T cells in these mice. The T cells in the skin infiltrates of young K14/IL-7 mice are predominantly gammadelta T cells that express intermediate levels of TCR, are negative for E-cadherin, often lack expression of CD2, and include cells that coexpress NK1.1. T cells expressing intermediate levels of a TCR-alphabeta are also present in transgenic skin, and progressively increase in number as the mice age. Phenotypically similar intermediate gammadelta and alphabeta T cell subsets also constitute the major lymphocyte populations recovered from organ culture of normal mouse skin in the presence of IL-7, suggesting that the T cells that accumulate in the epidermis of K14/IL-7 mice are derived from precursors normally resident in skin. We conclude that intermediate TCR cells, some of which coexpress NK1.1, can be selectively expanded in skin under the influence of IL-7 produced locally. Our results also suggest that features of the epidermal microenvironment besides keratinocyte-derived IL-7 account for the normal predominance of Vgamma5 Vdelta1 DETC in mouse epidermis.

Animals↗
PubMed1997

Mobile atheroma of the aortic arch is an underestimated source of embolization.

BACKGROUND: Mobile atheroma are associated with increased perioperative strokes in patients undergoing coronary artery bypass surgery. Peripheral embolization is an additional risk. Transesophageal echocardiography (TEE) accurately identifies mobile atheroma. Recent reports have discussed the possible influence of anticoagulant therapy in promoting peripheral cholesterol embolization. METHODS: Fourteen patients with mobile atheroma were treated with anticoagulation. A review of literature reporting results and complications of anticoagulation in the treatment of this condition was compared with our recent experience. RESULTS: Between 1994 and 1996, 14 patients with peripheral embolization and mobile atheroma confirmed by TEE were anticoagulated. Clinical follow-up between 6 to 30 months has demonstrated no further evidence of systemic embolization since anticoagulation. Furthermore, repeat TEE in 3 of 14 patients no longer visualized mobile atheroma. CONCLUSIONS: Mobile atheroma are recognized sources for embolization. Patients with generalized atherosclerosis should be screened for this condition in cases of systemic embolization. Anticoagulation may have therapeutic considerations in the management of this condition.

Aged↗
PubMed1996

Constitutive expression of B7-1 (CD80) on mouse keratinocytes does not prevent development of chemically induced skin papillomas and carcinomas.

Expression of the B7-1 (CD80) costimulatory molecule in a variety of tumor cell lines leads to an enhanced CD8+ T cell response to tumor Ags. We used transgenic mice constitutively expressing B7-1 on keratinocytes (K14/B7-1 line) to determine whether keratinocyte B7-1 expression would inhibit the development of papillomas and carcinomas following two-stage chemical carcinogenesis in skin. FVB inbred mice carrying the K14/B7-1 transgene and controls were initiated with 25 micrograms of 7,12-dimethylbenz[a]anthracene and promoted weekly with 5 micrograms of 12-O-tetradecanoylphorbol-13-acetate for 20 wk. Expression of the B7-1 transgene did not result in statistically significant decreases in the mean number of papillomas or carcinomas compared with controls. The incidence of carcinomas in both transgenic and control mice reached 90% or greater by 60 wk after initiation. Carcinoma cell lines established from the K14/B7-1 mice maintained expression of B7-1 and Kq. These B7-1 expressing carcinomas grew progressively following intradermal injection into syngeneic FVB mice, further demonstrating their inability to evoke protective tumor immunity. These same carcinoma cell lines were rapidly rejected by minor alloantigen-mismatched SWR mice, confirming their susceptibility to immune effector mechanisms. The failure of constitutive B7-1 expression on keratinocytes to prevent the growth of squamous cell papillomas and carcinomas may reflect the limited immunogenicity of tumors arising after initiation-promotion carcinogenesis. Our results in this transgenic model system are further evidence that B7-1 gene therapy alone may not be sufficient to induce protective immunity to some types of tumors.

Animals↗
PubMed1996

Optic aphasia: a case with spared action naming and associated disorders.

AG, a pure case of optic anomia (object naming impaired; action naming good) is described. We consider the fit of experimental data from AG to different theoretical accounts of optic aphasia. Overall, we find no evidence for impairments intrinsic to semantic representations, but we note a number of problems that we interpret as indicating a slight, and specific, weakness in semantic access from vision. We also note a mild problem in generating names to a cue (verbal fluency). The main aim of the report was to provide a full description of tests of visual, semantic, and speech output skills in this patient in relation to the processing of visually presented objects and scenes, within a sequential information processing account which enables some theoretical implications to be drawn, albeit not conclusively.

Adult↗
PubMed1996

Two routes to naming: a case study.

We report the case of an aphasic patient, KP, whose spontaneous speech and ability to communicate verbally were severely reduced. His comprehension of written words was preserved. Naming was relatively preserved for objects but impaired for actions. We designed experiments to investigate his verb processing and sentence completion. KP's knowledge of verb syntax was impaired in contrast to his relatively preserved knowledge of verb semantics. His ability to retrieve a noun on visual confrontation was significantly better than his ability to retrieve the same pool of nouns through propositional language. We interpret the data in terms of two 'routes' to noun-retrieval, a nominal route and a propositional speech route. Furthermore, we suggest that the dissociation between verb syntax and verb semantics can also be accounted for within this framework.

Aged↗
PubMed1996

Use of intravascular ultrasound in the endovascular management of atherosclerotic aortoiliac occlusive disease.

BACKGROUND: Intravascular ultrasound (IVUS) has been described as interesting technology in search of a clinical application by some and by others as a valuable diagnostic tool for many endovascular interventions. Its clinical usefulness has yet to be fully defined. When used during endovascular interventions, it can provide structural and diagnostic information, assess effectiveness of the therapy, and identify treatment-related complications. METHODS: Thirty-two consecutive patients with atherosclerotic aortoiliac occlusive disease who presented with 40 separate arterial lesions were evaluated with IVUS before and after balloon angioplasty and intraluminal stent placement. Information obtained from IVUS was compared with similar data obtained from simultaneous angiographic images. Both techniques were evaluated with respect to assessment of vessel size, lesion location, adequacy of therapy, and identification of complications. RESULTS: Real time IVUS imaging compared with angiographic imaging showed that in 62% of the patients, vessel diameter was underassessed using angiographic criteria alone. More importantly, 40% (16 of the 40 lesions) had underdeployed stents by IVUS evaluation that appeared adequately expanded by angiographic criteria. Further stent expansion with a larger balloon was necessary to achieve accurate stent to vessel wall apposition. This was found to be significant by an exact binomial 95% confidence interval. Incomplete stent deployment has been identified as a possible cause for restenosis and vessel occlusion. Information obtained from IVUS imaging substantially altered the endovascular therapy in approximately 40% of our patients and provided valuable vessel sizing and lesion composition information in 62% of the patients. CONCLUSION: Intravascular ultrasound can provide important diagnostic information that can alter the conduct of selected endovascular procedures. It is especially useful when the procedure requires deployment of arterial stents.

Adult↗
PubMed1995

Bioavailability of pseudoephedrine from controlled release formulations in the presence of guaifenesin in human volunteers.

A multiple-dose bioequivalence study with six healthy human volunteers was conducted. The bioavailability of an experimental controlled release tablet containing pseudoephedrine was compared with a marketed controlled release pseudoephedrine capsule in a three-way crossover study. Plasma samples, collected serially after oral drug administration, were analyzed for pseudoephedrine content using a specific HPLC method with UV detection. The bioavailability parameters, area under the concentration-time curve (AUC), maximum plasma concentration Cmax, and time to peak (Tmax) were obtained from the plasma concentration-time data. Additionally, model independent pharmacokinetic parameters were estimated. Analysis of variance of the data revealed no statistically significant differences between the test and the reference formulation. The presence of guaifenesin in the sustained release tablet did not influence pseudoephedrine bioavailability. The relative bioavailability of the tablet dosage form with respect to the capsule was found to be 100.8%. Classical and Westlake 95% confidence limits as well as the two one-sided t test, proposed by Schuirmann, and the Anderson-Hauck power analysis supported the inference that the two formulations demonstrated comparable bioavailabilty, even in the presence of guaifenesin. Using a non-linear regression program, it was found that the pharmacokinetics of pseudoephedrine followed a simple one-compartment disposition model with no lag time. Additionally, an in vitro-in vivo correlation, based on the estimation of cumulative relative fraction absorbed, was developed between the absorption of pseudoephedrine in humans and the in vitro dissolution time.

Adrenergic Agents↗
PubMed1992

Optic aphasia with spared action naming: a description and possible loci of impairment.

A brief functional description is given of an optic aphasic patient, A.G., who shows a pure and isolated deficit in naming visually presented objects on confrontation, but with sparing of visual action names. We show how some tasks related to imagery are compromised in this patient and speculate on possible functional site(s) of impairment in terms of the routes from perception to naming. We suggest why action naming may be spared in such cases.

Anomia↗