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Biomedical subjects

J D Bennett

Publications and source records attributed to J D Bennett.

At least 19 recordsLinked to original sources
PubMed1999

CT assessment of cerebral perfusion: experimental validation and initial clinical experience.

PURPOSE: To validate a dynamic single-section computed tomographic (CT) method to measure cerebral blood volume (CBV) and cerebral blood flow (CBF) by using a noncarotid artery as the input and to demonstrate the feasibility of this method in a pilot series of patients. MATERIALS AND METHODS: Twelve dynamic contrast material-enhanced CT studies were performed in beagles. CBV, CBF, and mean transit time (MTT) values were calculated by using an internal carotid artery (ICA) and a noncarotid artery as the input artery to the brain. Patient studies with use of the radial artery as the input were performed (a) repetitively in two patients after subarachnoid hemorrhage, (b) in a patient with a symptomatic ICA occlusion before and after the intravenous injection of 1 g of acetazolamide, and (c) in a patient with a malignant brain tumor. RESULTS: Linear regression analyses revealed highly significant correlations (P < .001) between CBV (r, 0.98; slope, 0.96), CBF (r, 0.89; slope, 0.87), and MTT (r, 0.80; slope, 0.76) values calculated with the ICA and the noncarotid inputs. The CT-derived patient data correlated well with ancillary clinical and neuroradiologic findings. CONCLUSION: Dynamic single-section CT scanning to measure CBV and CBF on the basis of a noncarotid input is a highly accessible and cost-effective blood flow measurement technique.

Animals↗
PubMed1998

Measurement of the scaphoid humpback deformity using longitudinal computed tomography: intra- and interobserver variability using various measurement techniques.

The intra- and interobserver variability of 3 techniques for measuring the humpback deformity of 37 scaphoids using longitudinal computed tomography was assessed. The 3 measuring techniques were the lateral intrascaphoid angle, the dorsal cortical angle, and the height-to-length ratio. The intraobserver reliability of the intrascaphoid angle was poor; the dorsal cortical angle was moderate to excellent, and the height-to-length ratio was excellent. The interobserver reliability of the intrascaphoid angle was poor to moderate, the dorsal cortical angle was moderate to excellent, and the height-to-length ratio was moderate to excellent. For all 3 observers, the intra- and interobserver reliability was the best for the height-to-length ratio and worst for the intrascaphoid angle. The height-to-length ratio is the most reproducible method of assessing the humpback deformity. Clinical correlation is required to establish whether the height-to-length ratio will be of value in predicting the outcome of fractures of the scaphoid.

Carpal Bones↗
PubMed1998

Bronchogenic cyst: an unusual cause of lump in the neck.

Bronchogenic cysts are rare congenital benign lesions that are usually detected in the paediatric patient with symptoms of infection or compression on vital structures. They are rarely diagnosed in the adult population. We present a case of bronchogenic cyst presenting as a lump in the neck in an adult patient. Radiological imaging helped to diagnose this lesion accurately before any form of intervention. Complete surgical excision is the treatment of choice.

Bronchogenic Cyst↗
PubMed1998

Sequence comparison of avian infectious bronchitis virus S1 glycoproteins of the Florida serotype and five variant isolates from Georgia and California.

The infectious bronchitis virus (IBV) spike glycoprotein S1 subunit is required to initiate infection and contains virus-neutralizing and serotype-specific epitope(s). Reported are the S1 gene nucleotide and predicted amino acid sequences for the Florida 18288 strain and isolates GA-92, CV-56b, CV-9437, CV-1686, and 1013. These sequences were compared with previously published gene sequences of IBV strains, and phylogenetic relationships are reported. The S1 amino acid sequence of Florida 18288 was 94.9% similar to the Connecticut strain, and GA-92 was 92.8% similar to the Arkansas 99 strain. S1 amino acid sequences of the California variants, CV-56b, CV-9437, and CV-1686, were 97.6-99.3% similar to one another and only 76.6%-76.8% similar to the Arkansas-type strains. Isolate 1013, also from California, was 84.0% similar to Ark DPI and 77.9% similar to CV-56b. When comparing 19 viruses isolated from the United States, sequence variations were observed between amino acids 55-96, 115-149, 255-309, and 378-395. Similar regions are reported to be involved in virus-neutralizing and/or serotype-specific epitopes. These data demonstrate that variant IBV strains continue to emerge, and unique variants may circulate among poultry in geographically isolated areas.

Amino Acid Sequence↗
PubMed1998

Treatment of xanthelasma palpebrarum with bichloracetic acid.

BACKGROUND: Although many treatment modalities have been described for xanthelasma palpebrarum, no single technique has emerged as dominant. OBJECTIVES: Our purpose was to review the various therapeutic modalities for xanthelasma and to assess the efficacy of topical bichloracetic acid. METHODS: Thirteen patients with 25 xanthelasma were treated with topical 100% bichloracetic acid. Efficacy was assessed over a follow-up period of 7 months to 10.5 years (average, 64 months). RESULTS: Eighty-five percent of patients experienced initial complete clearing, and 72% of their lesions have not required retreatment over an average period of 68 months. Recurrences responded well to repeat treatment. Eighty-three percent of recurrent or poorly responsive lesions were associated with high cholesterol. The most resistant patient had four-lid involvement. Excellent cosmetic results and high patient satisfaction were seen. CONCLUSIONS: Topical bichloracetic acid is a viable alternative to other modalities in the management of xanthelasma. Advantages include simplicity, cost-effectiveness, speed, safety, and efficacy.

Administration, Cutaneous↗
PubMed1998

Diagnostic pitfalls in sports related laryngeal injury.

The serious nature of laryngeal trauma sustained during sporting activity can be easily overlooked. Concomitant injury should not distract from the diagnosis of potential airway problems. The effects of head and neck trauma on the airway may be delayed. The assessment and management of a patient with suspected laryngeal injury should be carried out by experienced medical practitioners.

Adult↗
PubMed1998

Complications of radiologically placed central venous ports and Hickman catheters in patients with AIDS.

OBJECTIVE: To determine any differences in the complications following radiologic placement of 2 devices--Hickman catheters and central venous ports--to permit long-term central venous access in patients with AIDS. PATIENTS AND METHODS: Thirty-eight patients with AIDS received 52 long-term central venous access catheters. Seventeen received 23 Hickman catheters and 27 received 29 central venous ports (hence, 6 patients received both). Complications rates were determined retrospectively from clinical records and radiologic studies. RESULTS: The only acute complications were pneumothoraces--3 in the patients receiving Hickman catheters and 2 in the patients receiving central venous ports. Infections developed in 12 of the patients receiving Hickman catheters a median of 53 and a mean of 96 days after placement. Infection developed in 8 of the patients receiving central venous ports a median of 125 days and a mean of 184 days after placement. This difference was statistically significant (p < 0.001). The most common organism in these infections was Staphylococcus aureus. The only other nonacute complication was 1 nonocclusive thrombosis of the superior vena cava, which occurred in a patient with a Hickman catheter 240 days after placement and resolved once the catheter was removed. CONCLUSION: Central venous ports are preferred over Hickman catheters for long-term central venous access in patients with AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1997

Scalene muscles and the brachial plexus: anatomical variations and their clinical significance.

Anatomical variations may be clinically significant, but many are inadequately described or quantified. Variations in neck anatomy are important to surgeons performing surgical procedures in this region. Thirty-two female and 19 male adult cadavers were studied. The commonly described anatomical relationship of the brachial plexus (BP) lying between the anterior scalene (AS) and middle scalene (MS) muscles was found in only 60% of instances. Scalenus minimus was present in 46% of instances (bilateral in 14 cadavers). The most common variation was the penetration of the AS by the C5 and/or C6 ventral rami. The C5 and C6 roots may fuse before piercing AS (15% cases, bilateral in 4 cadavers), or the C5 root alone pierce the belly of AS (13% cases, bilateral in 3 cadavers). The roots also may pierce AS independently (6% cases, bilateral in 1 cadaver). In 3%, the C5 root was found to be completely anterior to AS.

Brachial Plexus↗
PubMed1997

Arthroscopic diagnosis of intra-articular soft tissue injuries associated with distal radial fractures.

Arthroscopy was used to assess the soft tissue injuries associated with distal radial fractures in 118 acute intra- and extra-articular fractures. The triangular fibrocartilage complex (TFCC) was torn in 46 of 118 patients--in 35% of intra-articular fractures and in 53% of extra-articular fractures. No correlation between ulnar styloid fractures and TFCC injuries could be found. Scapholunate (SL) ligament injuries with instability were present in 21.5% of intra-articular fractures and in 6.7% of extra-articular fractures. Lunotriquetral (LT) ligament injuries with instability were present in 6.7% of intra-articular fractures. and in 13.3% of extra-articular fractures. Combined SL and LT injuries were present in 5.6% of intra-articular fracture. Preoperative radiographs correlated with TFCC injury. Patients with TFCC tears had greater shortening and dorsal angulation on the preoperative radiographs. Preoperative radiographs had no predictive value for interosseous ligament injury. Ligamentous injuries are commonly associated with both intra-articular and extra-articular distal radial fractures.

Adolescent↗
PubMed1997

Informed consent: patients' and junior doctors' perceptions of the consent procedure.

The important task of obtaining informed consent is often left to the most junior member of the surgical team, whose understanding of the surgical procedures involved may be limited. Little is known about patients' and junior doctors' satisfaction with the consent procedure, which was studied with the use of questionnaires. The vast majority of patients (95%) were satisfied with the explanation given to them prior to obtaining consent although 45% thought that the doctor who signed the consent form would be performing the surgery. Thirty-seven per cent of the junior doctors questioned admitted to obtaining consent for procedures of which they had little understanding. The majority of both junior doctors and patients felt that the surgeon performing surgery should sign the consent form. Junior doctors cannot be expected to obtain informed consent for procedures they do not fully understand and patients's; expectations must be taken into consideration if the seemingly inexorable rise in medico-legal litigation is to be halted.

Attitude of Health Personnel↗
PubMed1997

Abnormalities of the hook of the hamate in patients with carpal tunnel syndrome.

The hook of the hamate is an important landmark in endoscopic carpal tunnel release. We studied the incidence of abnormalities of the hook of the hamate in patients with carpal tunnel syndrome. One hundred thirty-one consecutive patients presenting with carpal tunnel syndrome underwent carpal tunnel radiography. Abnormalities of the hook of the hamate were present in 6 of 131 patients (4.6%). The hook of the hamate was aplastic in 3 of 131 patients (2.3%). A bipartite hook of the hamate was present in 1 patient (0.8%). A nonunion of an old fracture of the hook of the hamate was found in two patients (1.6%). The previously reported incidence of an aplastic hook of the hamate in the general population is 1 of 1,452 (0.06%). The odds ratio revealed a 34-fold increase in the risk of hamate abnormalities in the carpal tunnel population (p < 0.001). Hook of the hamate abnormalities may be more common than previously reported.

Adolescent↗
PubMed1996

E2F binding is required but not sufficient for repression of B-myb transcription in quiescent fibroblasts.

We have previously shown in mouse NIH3T3 fibroblasts that transcription of the B-myb gene, which encodes a transcription factor required for S phase entry, is repressed through a promoter E2F site in G0/early G1. Transcription repression at this stage of the cell cycle was correlated with binding of a specific p107/E2F complex to this site. We report here, however, that transfection of cells with the known components of this complex, p107, E2F-4 and DP-1, did not repress the B-myb promoter in cycling NIH3T3 cells, although p107 inhibited transcription transactivation by E2F-4/DP-1. To establish definitively the contribution of E2F to repression, the effects of further mutations within and surrounding the E2F site were examined. It was evident that E2F binding and repression were closely correlated, lending greater weight to the contention that E2F itself is implicated in this activity. These studies also identified a closely linked site, designated the downstream repression site (DRS), which was not required for E2F binding or transactivation but which was necessary for repression. These findings indicated that E2F-dependent repression and activation are independently regulated phenomena and suggest that repression involves additional interactions determined by the promoter context.

3T3 Cells↗
PubMed1996

Characterization of Newcastle disease virus vaccines by biological properties and sequence analysis of the hemagglutinin-neuraminidase protein gene.

Six commercially available monovalent Newcastle disease virus (NDV) live-vaccines were examined for their biological and genomic stability in comparison to their stated parent virus. Thermostability of the hemagglutinin at 56 degrees C for 5 min was consistently observed among the majority of the vaccine viruses. One exception was a recently developed NDV vaccine isolated from turkeys that had a thermostability of 15 min. Neuraminidase activity, as measured by elution rate of agglutinated red blood cells, varied among vaccine viruses and correlated with that of the parent isolate. Virulence as measured by intracerebral pathogenicity index ranged from 0 to 0.39 among NDV vaccine-type viruses, well within the range of avirulent lentogens. Sequence of the fusion protein cleavage site from all the NDV vaccine isolates examined was consistent with that for lentogens. The entire hemagglutinin-neuraminidase gene sequence was 98% similar among all the NDV vaccine viruses examined and phylogenetic classification of commercial vaccine types correlated with their respective parent virus. Consequently, the commercially produced NDV vaccines reported here appear relatively stable when mass produced in avian embryonated eggs.

Amino Acid Sequence↗
PubMed1996

High tracheostomy and other errors--revisited.

Timely cricothyrotomy may be life-saving, but it is not without its complications. Together with tracheostomy performed too high, there are high incidences of stenosis and voice changes afterwards-often neglected because the patient has so many other problems. Jackson warned of these problems over 70 years ago-his message is still relevant.

Cricoid Cartilage↗
PubMed1996

Cricothyrotomy: the anatomical basis.

Cricothyrotomy is an important surgical technique. We studied the anatomy of the cricothyroid membrane in 13 adult fresh cadavers preserved at 45 degrees F and examined at 70 degrees F. The working dimensions of the cricothyroid membrane were measured for emergency cricothyrotomy and placement of an airway tube. The vertical measurement ranged from 8-19 mm (mean 13.69 +/- SE 0.96 mm) and the maximal width between the cricothyroid muscles ranged between 9 and 19 mm (mean 12.38 +/- SE 0.91 mm). The distance from the upper limit of the cricothyroid membrane to the vocal cord was 9.78 +/- SE 0.52 mm. Eight subjects (62%) had an artery delineated transversely across the cricothyroid membrane. Two subjects (15%) had sclerosis of the cricothyroid joint. To promote the safe use of cricothyrotomy, the anatomy of the cricothyroid membrane is defined and clinically relevant data are presented.

Cadaver↗