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Biomedical subjects

D Hardy

Publications and source records attributed to D Hardy.

At least 19 recordsLinked to original sources

Surgical management of trigeminal neuromas: a report of eight cases.

OBJECTIVE: Trigeminal neuromas are rare tumours that may involve any part of the Vth nerve complex, including extracranial peripheral divisions of the nerve. A series of eight patients with intracranial trigeminal neuromas who underwent surgical management are presented. METHODS: The hospital records and radiological images were reviewed with regard to clinical presentation, surgical approach, operative findings, peri-operative morbidity and neurological outcome, and percentage of tumour recurrence. RESULTS: The principal presenting symptoms were those of involvement of the trigeminal nerve with sensory impairment in one or more of the three divisions. Tumour location was the prime determinant of surgical approach. Lateral skull base approaches were used as they are considered to be superior for identifying tumour origin, extension, and relationship to surrounding structures. Total excision of the tumour was carried out in three of the eight patients. In the remaining five patients some tumour was left purposely in order to minimize neurological deficit and optimize post-operative quality of life. There was no peri-operative mortality or major morbidity in our series. Five patients experienced symptomatic tumour recurrence and revision surgery was performed. CONCLUSION: Management of trigeminal neuromas is complex and requires a multidisciplinary approach. Pre-operative surgical planning allows tumour removal with preservation of important neural structures in the majority of cases. For large tumours occupying both the middle and posterior cranial fossae, the retrosigmoid/retrolabyrinthine/middle cranial fossa approach provides good exposure and results in minimal brain retraction. A Fisch type C approach is necessary for the largest tumours. Long-term follow up with interval imaging is mandatory to exclude long-term tumour recurrence.

Adult↗

Standards for head injury management in acute hospitals: evidence from the six million population of the Eastern region.

OBJECTIVES: To develop standards of care for head injury and thereby identify and prioritize areas of the service needing development; to report the findings from a survey of compliance with such standards in the Eastern region of UK. METHODS: The standards were collaboratively developed through an inclusive and iterative process of regional surveys, multidisciplinary conferences, and working groups, following a method similar to that used by the Society of British Neurological Surgeons. The standards cover seven topics relating to all aspects of service delivery, with standards within each objective. Each standard has been designated a priority level (A, B, or C). The standards were piloted using a self-assessment questionnaire, completed by all 20 hospitals of the Eastern region. RESULTS: Full compliance was 36% and a further 30% of standards were partially met across the region, with some areas of service delivery better than others. Seventy eight per cent of level A standards were either fully or partially met. Results were better in the north of the region compared with the south. CONCLUSION: A survey of compliance with the head injury standards indicate that, with their whole systems approach and subject to further refinement, they are a useful method for identifying deficiencies in service provision and monitoring for quality of care both within organisations and regionally.

Craniocerebral Trauma↗

The effect of cooking on veterinary drug residues in food: nicarbazin (dinitrocarbanilide component).

The change of concentration of residues of the marker compound for the anti-coccidial drug nicarbazin, N,N'-bis(4-nitrophenyl)urea (dinitrocarbanilide, DNC), was investigated in model oil and aqueous solutions and in chicken muscle and egg. In model aqueous solutions, DNC decreased rapidly in concentration upon heating followed by a much more gradual decomposition. The curves produced when this information was plotted were not typical of exponential decay. In model cooking oil solutions, DNC generally showed a slower decrease in concentration over time when compared with aqueous solutions. DNC residues in egg were stable to microwave cooking and residues in chicken muscle were stable to stewing and microwaving. Other cooking procedures led to a decrease in amount of DNC by 22% to 48% of the total amount of analyte present. Only a small amount (<2%) of residue leached with juices which exuded as the food was cooked.

Animals↗

Are the strokes in moyamoya syndrome associated with Down syndrome due to protein C deficiency?

Moyamoya syndrome has occasionally been seen in association with Down syndrome. We report a child with moyamoya syndrome and Down syndrome who was admitted with repeated episodes of strokes; his magnetic resonance imaging and magnetic resonance angiography findings confirmed the presence of occlusive cerebrovascular disease with basal collateral vessels. His protein C levels were significantly decreased during the stroke. Complete clinical recovery was seen during follow-up. This raises the possibility of a link between protein C deficiency and Down syndrome with moyamoya syndrome.

Child, Preschool↗

Malignancy in a vestibular schwannoma. Report of a case with central neurofibromatosis, treated by both stereotactic radiosurgery and surgical excision, with a review of the literature.

Malignant change in schwannoma is rare. Malignant change in a vestibular schwannoma (acoustic neuroma) is even more rare. This paper presents a case of rapidly growing vestibular schwannoma first treated by radiosurgery whose histopathology after surgical excision 42 months later showed malignant changes. Up to now, eight cases of malignancy in eighth nerve tumours have been reported, four of which, including the present case, had previously been treated with radiosurgery and four cases that had not received radiation. Thus, it would seem, the overall incidence is extremely low. Nevertheless, extreme vigilance and careful reporting continues to be necessary.

Adult↗

Identification and characterization of a family of Rab11-interacting proteins.

Rab11a is a small GTP-binding protein enriched in the pericentriolar plasma membrane recycling systems. We hypothesized that Rab11a-binding proteins exist as downstream effectors of its action. Here we define a family of four Rab11-interacting proteins: Rab11-Family Interacting Protein 1 (Rab11-FIP1), Rab11-Family Interacting Protein 2 (Rab11-FIP2), Rab11-Family Interacting Protein 3 (Rab11-FIP3), and pp75/Rip11. All four interacting proteins associated with wild type Rab11a and dominant active Rab11a (Rab11aS20V) as well as Rab11b and Rab25. Rab11-FIP2 also interacted with dominant negative Rab11a (Rab11aS25N) and the tail of myosin Vb. The binding of Rab11-FIP1, Rab11-FIP2, and Rab11-FIP3 to Rab11a was dependent upon a conserved carboxyl-terminal amphipathic alpha-helix. Rab11-FIP1, Rab11-FIP2, and pp75/Rip11 colocalized with Rab11a in plasma membrane recycling systems in both non-polarized HeLa cells and polarized Madin-Darby canine kidney cells. GFP-Rab11-FIP3 also colocalized with Rab11a in HeLa cells. Rab11-FIP1, Rab11-FIP2, and pp75/Rip11 also coenriched with Rab11a and H(+)K(+)-ATPase on parietal cell tubulovesicles, and Rab11-FIP1 and Rab11-FIP2 translocated with Rab11a and the H(+)K(+)-ATPase upon stimulating parietal cells with histamine. The results suggest that the function of Rab11a in plasma membrane recycling systems is dependent upon a compendium of protein effectors.

Amino Acid Sequence↗

A self-assessment program for multidisciplinary mental health teams.

OBJECTIVE: The authors describe a self-assessment training program for multidisciplinary mental health teams that was developed in a public multihospital system, the process of implementing the training at a state psychiatric hospital, and a measurement instrument, the Scale for Leadership Assessment and Team Evaluation (SLATE), which they have used for self-assessment of multidisciplinary teams and which is currently being studied. They assessed whether changes in team self-assessments could be seen after the training program. METHODS: A total of 102 mental health professionals from 12 inpatient units representing the disciplines of psychiatry, psychology, nursing, social work, and occupational and activity therapy completed the SLATE before and after participation in a training program that consisted primarily of team self-assessment in the context of treatment planning sessions. The training program included structured feedback, didactics, consultation, and videotaping of sessions. Aggregate data were used to compare mean item scores for the SLATE overall and for its four subscales (team, psychiatrist, participation, and treatment plan) at baseline and after the training. RESULTS: Scores increased significantly for the overall SLATE and for all four subscales, indicating improved team functioning in the areas addressed. The increase in mean score was greatest for the subscale that assessed the leadership of the psychiatrist. CONCLUSIONS: Treatment planning sessions can be used successfully by multidisciplinary mental health teams to examine team functioning in various areas in a self-assessment model. Participation in a training program that included videotaping of sessions, consultation, and structured attention to team functioning was associated with improved ratings of team functioning.

Case Management↗

A comparison of routine and rapid microwave tissue processing in a surgical pathology laboratory. Quality of histologic sections and advantages of microwave processing.

Rapid processing of histopathologic material is becoming increasingly desirable to fulfill the needs of clinicians treating acutely ill patients. Traditional techniques for rapid processing of paraffin-embedded tissues require 4 to 5 hours, delaying treatment for some critically ill patients and requiring additional shifts of technologists in the laboratory. Microwave processing further shortens this time, allowing even more rapid histopathologic diagnosis. Few data exist comparing quality of microwave-processed tissue with that processed by more traditional techniques. We randomly selected 158 paired specimens from 111 patients. One member of the pair was processed routinely overnight, while the other was processed by the rapid microwave technique. The slides then were compared for quality of histologic preparation in a blinded fashion by 2 pathologists. Eight routinely processed specimens were judged as suboptimal, while 6 microwave-processed specimens were judged as suboptimal and 1 was considered unsatisfactory for evaluation. In the remaining cases, the material obtained by the 2 techniques was considered of identical quality. Microwave processing considerably shortens the preparation time for permanent histologic sections without a demonstrable decrease in section quality or "readability."

Female↗

[Shock absorption by intermediate hip prostheses].

PURPOSE OF THE STUDY: The bipolar prosthesis was developed in an attempt to alleviate acetabular wear of conventional metallic endoprostheses. The prosthesis was designed to achieve low-friction metal-on-polyethylene inner bearing motion while decreasing shear stress across the acetabular cartilage. Although good clinical results were obtained, the principle of a persistent inner mobility was contested and some authors have assigned the delay of cartilage erosion to the shock absorption capacity of the polyethylene. The present study was focused on assessing the vibration and shock damping effect of metal monoblock and bipolar head prostheses. MATERIAL AND METHODS: The transmission of the shock wave through these two types of prostheses was studied in vitro. The two heads were first tested in a rigid environment to eliminate all external parasite frequencies. The impact excitation was applied with a hammer connected to an oscillometer. A second accelerometer was connected to the prosthesis stem. Shock wave transmission was analyzed. Secondly, the head was tested with a system vibrating in the same order of frequencies as the skeleton, with and without pre-constraint. The frequency response functions were analyzed. RESULTS: For the metallic prosthesis, the frequency of vibration recorded on the femoral stems was in a large frequency range from 0 Hz to 10 KHz. For the bipolar prosthesis, all the high frequencies of the shock wave were eliminated and only shock wave frequencies from 0 to 500 Hz were recorded. In an environmental system vibrating below 100 Hz, the metallic head did not express high frequencies of vibration. The coefficient of shock absorption was not significantly different for the two heads. DISCUSSION: In the first rigid environment, the metallic head did not filter the high frequency components of the shock wave and the bipolar head tended to eliminate high frequency components due to the flattening effect of the impulse load by the polymer. But, the lower leg is not a rigid structure and the musculo-skeletal system vibrates in frequencies below 100 Hz. In similar conditions, the increased shock-absorbing effect of the polyethylene is far more difficult to observe. For the metallic prosthesis, the recorded frequency of vibration also belongs to a small domain of frequency, from 0 Hz to 100 Hz. The range of frequency is similar for the two types of prostheses. CONCLUSION: Even though polyethylene is characterized by a more pronounced damping capacity than metallic materials, in experimental conditions simulating the vibratory characteristics of the human body, the introduction of a high-density polyethylene liner does not afford any additional shock-absorbing effect compared with a metallic head. It cannot explain cartilaginous sparing.

Equipment Failure Analysis↗

Biomechanical evaluation of Hackethal's intramedullary bundle pin fixation of humeral neck fractures.

Humeral neck fractures can be stabilized using a bundle of intramedullary pins as described by Hackethal. In order to decrease the risk of pin migration, packing of the medullary cavity with as many pins as possible is sometimes recommended, but others believe that stability can be decreased by destruction of cancellous bone in the humeral head by a large bundle of pins. A surgical neck fracture was created with a saw in 30 frozen cadaveric humeri. Bone quality was evaluated by radiography and densitometry. Fractures were stabilized using Hackethal's technique of retrograde intramedullary pinning with varying numbers of 2.5-mm diameter pins; increasing torsion or bending moments of force were then applied to the bones studied. Stability was found to improve with an increasing number of pins and with higher humeral head density. Based upon these findings, the use of a large number of pins is recommended to reduce the risk of pin migration. Up to eight pins, the risk of destruction of cancellous bone in the humeral head appears very low.

Biomechanical Phenomena↗

System-Wide Action Team (SWAT)--a new level of collaboration.

A multidisciplinary System-Wide Action Team was coordinated by nursing leadership in response to increasing patient census and acuity. The primary objectives of the team were to develop mechanisms that would expedite patient's admissions and discharges, communicate key messages to all concerned staff, support each other, and communicate announcements about topics or urgent issues that relate to managing the hospital. The team has implemented improvement initiatives around diagnostic testing and scheduling, expediting the admission process, reducing discharge delays, and staffing to hospital census demands.

Cooperative Behavior↗

Phase 1 trial of a single dose of recombinant human interleukin-12 in human immunodeficiency virus-infected patients with 100-500 CD4 cells/microL.

A phase 1 dose-escalation trial of a single subcutaneous dose of recombinant human (rh) interleukin (IL)-12 was conducted in medically stable human immunodeficiency virus (HIV)-infected patients with 100-500/microL absolute CD4(+) T lymphocytes. Subjects at each dose level were randomly assigned (3:1) to receive rhIL-12 or placebo. Among the 47 subjects enrolled, rhIL-12 was well tolerated at doses of 3-300 ng/kg, but 4 of 5 subjects who received rhIL-12 at 1000 ng/kg had severe adverse events. Dose-related increases in serum interferon-gamma occurred after rhIL-12 administration at doses > or =30 ng/kg. There was no effect of rhIL-12 on plasma HIV RNA or absolute CD4(+) T cell counts. However, dose-related increases in absolute CD8(+) T and NK cells were observed in subjects assigned to rhIL-12 doses of 30-300 ng/kg. Single rhIL-12 doses of 30-300 ng/kg were well tolerated and had biologic activity that could potentially be of benefit in the treatment of HIV disease or its complications.

Adult↗

Comparative in vitro activities of ciprofloxacin, gemifloxacin, grepafloxacin, moxifloxacin, ofloxacin, sparfloxacin, trovafloxacin, and other antimicrobial agents against bloodstream isolates of gram-positive cocci.

The in vitro activity of gemifloxacin against 316 bloodstream isolates of staphylococci, pneumococci, and enterococci was compared with the activities of six fluoroquinolones and three other antimicrobial agents. Of the antimicrobial agents tested, gemifloxacin was the most potent against penicillin-intermediate and -resistant pneumococci, methicillin-susceptible and -resistant Staphylococcus epidermidis isolates, and coagulase-negative staphylococci.

Anti-Bacterial Agents↗