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Biomedical subjects

D Bennett

Publications and source records attributed to D Bennett.

At least 91 records · Page 5Linked to original sources
PubMed1998

Late-onset sporadic progressive subcortical gliosis.

We report two sporadic cases of progressive subcortical gliosis (PSG) with onset after age 60. The presentation included slowly progressive dementia with memory loss, geographic disorientation, and personality change. Both were diagnosed clinically as Alzheimer's disease (AD) and both met NINCDS-ADRDA criteria for probable AD. Autopsy revealed generalized atrophy, predominantly involving the white matter of the frontal and temporal lobes. Microscopically, prominent fibrillary astrocytosis was present in the subcortical white matter and in the subpial and deep layers of the overlying cerebral cortex. Mild cortical neuron loss accompanied the gliosis, but no myelin loss was evident. Amyloid deposits and neuronal cytoskeletal inclusions were absent.

Aged↗
PubMed1998

Femoral neck metaphyseal osteopathy in the cat.

This paper describes 17 cats that developed an idiopathic necrosis of the femoral neck. In four cats the lesions were bilateral when they were first examined and five cats developed lesions in the other limb within five months. They were all male cats, two years old or younger, and 15 had been neutered. The initial sign was a vague lameness which typically progressed, often acutely, to a more severe lameness. Radiography demonstrated radiolucency and loss of definition within the proximal femoral metaphysis, the femoral neck. In 12 cases there was a complete radiolucent line across the femoral neck. An excision arthroplasty was carried out on all the affected hips and the lameness resolved in all cases. The clinical and radiological signs suggest a primary bone resorption with secondary fracture of the femoral neck. The lesions have some similarities with Legg-Calve-Perthes' disease, traumatic fracture of the femoral neck, canine metaphyseal osteopathy, bacterial osteomyelitis and experimental feline herpes virus osteomyelitis.

Animals↗
PubMed1998

An ecological model for school-based mental health services for urban low-income aggressive children.

An ecological model for school-based mental health services that targets urban low-income aggressive children--a highly vulnerable and underserved population--is presented. The goals of the model are to increase children's and teachers' involvement in the delivery of services and to increase the integration of these services into existing school resources and activities. The model proposes that mental health service providers work in collaboration with teachers to deliver services that (1) can be managed by existing school resources and personnel, (2) are related to empirically based factors associated with reduced aggression and increased social functioning, and (3) are group administered to increase the number of children served and to reduce stigmatization associated with mental health services. The model is individualized and flexible by acknowledging that contexts for aggression differ across classrooms and children and by providing services specific to those contexts. Two studies are presented illustrating the application of this model to decrease aggression and increase academic engagement in low-income urban public schools.

Achievement↗
PubMed1998

Notification of tuberculosis in patients with AIDS.

BACKGROUND: In the early 1990s cases of tuberculosis in people with HIV infection and AIDS were undernotified. A study to evaluate changes in notification rates in two inner London local authorities was undertaken for the period January 1993-June 1996 inclusive. METHODS: For residents of the two local authorities, tuberculosis notifications were identified using a local database, and cases of AIDS with a recorded diagnosis of tuberculosis were identified from AIDS case reports. RESULTS: During the study period, only 13 (32 per cent) of the 41 AIDS cases with a recorded diagnosis of tuberculosis were also notified as a case of tuberculosis. However, the proportion of notified cases rose from 0 per cent (0 of 11) in 1993 to 50 per cent (5 of 10) in 1995 and 63 per cent (5 of 8) in early 1996. CONCLUSION: The increase in the tuberculosis notification rate for people with AIDS is encouraging, but scope for improvement remains.

AIDS-Related Opportunistic Infections↗
PubMed1998

Management of disc-associated wobbler syndrome with a partial slot fenestration and position screw technique.

A previously unpublished surgical technique for the management of disc-associated wobbler syndrome is described. A series of 17 middle-aged dobermanns (mean age 7.4 years) with this condition were managed by a technique of partial slot fenestration and position screw fixation of the affected disc space (C6/7 in all cases). One patient was lost to follow-up and, of the remaining 16 cases, 13 improved following surgery (81 per cent). The three failures were a consequence of incorrect placement of one of the screws. Careful evaluation of immediate postoperative radiographs allows this problem to be identified; the screw can then be correctly repositioned with an immediate return to surgery.

Animals↗
PubMed1998

Binding of [3H]-SK&F 107260 and [3H]-SB 214857 to purified integrin alphaIIbbeta3: evidence for a common binding site for cyclic arginyl-glycinyl-aspartic acid peptides and nonpeptides.

The aggregation of activated platelets is mediated by the binding of fibrinogen to its cell surface receptor, the integrin alphaIIbbeta3. The recognition of fibrinogen by alphaIIbbeta3 depends, in part, on the tripeptide sequence Arg-Gly-Asp (RGD) in the adhesive protein. The interactions of a cyclic RGD-containing pentapeptide, [3H]-SK&F-107260, and a 1,4-benzodiazepine-based nonpeptide [3H]-SB-214857, with purified alphaIIbbeta3 have been investigated. Both compounds potently inhibit platelet aggregation at submicromolar concentrations. Binding of both [3H]-SK&F-107260 (Kd = 1.19 nM) and [3H]-SB-214857 (Kd = 1.85 nM) to alphaIIbbeta3 is of high affinity and fully reversible. The binding is monophasic, indicating a single class of noncooperative binding sites. The two radioligands exhibited similar values in binding to alphaIIbbeta3 purified on an RGD-affinity column (Bmax = 0.2 mol/mol alphaIIbbeta3) or to alphaIIbbeta3 purified over a lentil lectin column (Bmax = 0.03 mol/mol alphaIIbbeta3), suggesting that SK&F-107260 and SB-214857 interact with the same population of receptors. Binding of [3H]-SK&F-107260 and [3H]-SB-214857 to alphaIIbbeta3 require divalent cations, Mg++, Ca++ and Mn++ are able to support binding, with Mn++ being the most effective. Thirteen alphaIIbbeta3 antagonists, including four linear and three cyclic RGD peptides, five peptidomimetics, the fibrinogen gamma-chain dodecapeptide (HHLGGAKQAGDV) and the snake venom protein, echistatin, complete for [3H]-SK&F-107260 or [3H]-SB-214857 binding to alphaIIbbeta3. The affinity constants (Ki) of these compounds, determined by the two radioligand binding assays, are similar. Furthermore, these compounds exhibit the same rank order of potency in inhibiting biotinylated-fibrinogen binding to alphaIIbbeta3. Scatchard plot analyses of the [3H]-SK&F-107260 binding isotherms in the presence of unlabeled SB-214857 and gamma-chain dodecapeptide reveal competitive-type antagonism, indicating that SB-214857, gamma-chain dodecapeptide and SK&F-107260 interact with mutually exclusive binding sites on alphaIIbbeta3.

Binding, Competitive↗
PubMed1998

Evaluation of contamination of used disposable contact lenses by Acanthamoeba.

PURPOSE: The purpose of this study was to evaluate the contamination of used disposable soft contact lenses with Acanthamoeba. METHODS: We evaluated 51 consecutive disposable soft contact lens wearers in a prospective study. Before their check-up visits, patients were offered a free new contact lens in exchange for donating their old one. The used contact lenses (n = 102) were then removed and placed in culture medium for Acanthamoeba. We subsequently investigated patterns of wear and hygiene habits. RESULTS: The mean age of this population was 32.6 +/- 11.0 years. The average time of disposable soft contact lens wear was 13.7 hours per day. The contact lenses were disinfected daily with commercial solutions. Twenty-five (49.0%) subjects did not clean their lens cases properly. Acanthamoeba was not isolated from any of the 102 lenses. CONCLUSIONS: There were no cases of Acanthamoeba contamination in a small population of disposable soft contact lens wearers who regularly disinfected their lenses with standard commercially available contact lens solutions.

Acanthamoeba↗
PubMed1998

Porcine hepatic response to sepsis and its amplification by an adrenergic receptor alpha1 agonist and a beta2 antagonist.

1. We investigated the effect of adrenergic receptor stimulation or inhibition on the hepatic ultrastructural changes in a porcine faecal peritonitis model of multi-organ failure. We infused either the alpha1 adrenergic receptor agonist methoxamine or the beta2 adrenergic receptor antagonist ICI 118551 during 8 h of the study.2. Anaesthetized pigs (25-30 kg) were divided into four non-septic groups (control, non-septic, non-septic methoxamine and non-septic ICI 118551) and three septic groups (septic, septic methoxamine and septic ICI 118551).3. Changes in hepatic ultrastructure were measured by morphometric analysis. The septic group was significantly worse than all the non-septic groups. Septic methoxamine and septic ICI 118551 were significantly worse than the septic group.4. Septic methoxamine and septic ICI 118551 had a significantly increased perisinusoidal space; septic methoxamine had significant hepatocyte vacuolation.5. Hepatic ultrastructural changes were independent of hepatic blood flow.6. Septic methoxamine had significant myocardial depression.7. The alpha1 adrenergic receptor agonist methoxamine or the beta2 antagonist ICI 118551 both amplified the hepatic injury normally found during sepsis in our porcine model.8. These findings suggest that during sepsis a protective endogenous beta2 adrenergic receptor-mediated anti-inflammatory response is activated via cell membrane transduction to stimulate the trimeric G-protein complex Gs and activate the second cell messenger cAMP.9. In addition, it is likely that alpha1 adrenergic receptor agonists amplify the inflammatory response by stimulating the cell-surface receptor-linked trimeric G-protein complex to activate Gq and the second cell messenger phospholipase C.

Adrenergic alpha-Agonists↗
PubMed1997

Physical, psychiatric and social characteristics of the temporomandibular disorder pain dysfunction syndrome: the relationship of mental disorders to presentation.

OBJECTIVE: To investigate the physical and psychosocial characteristics and to identify the prevalence of mental disorders in pain dysfunction syndrome (PDS). DESIGN AND SETTING: New referrals to temporomandibular disorder clinics at Manchester Dental Hospital and diagnosed with PDS. METHODS: Patients were assessed with a range of socio-demographic, dental and psychosocial measures including a psychiatric interview. Patients with PDS and a mental disorder were compared with those without a mental disorder. RESULTS: 97 patients were included; 32 (33%) had a mental disorder. There were no significant differences between those with and those without a mental disorder on any of the objective dental measures. Those with a mental disorder complained of more pain associated with PDS. They reported more anxiety and depression and also more physical symptoms unrelated to the PDS for which they had sought help and received more treatments. CONCLUSIONS: Psychosocial factors contribute to the presentation and possibly causation of PDS in the third of patients seen in a hospital setting who have a mental disorder. This factors should be considered when managing patients with PDS.

Adolescent↗
PubMed1997

Case-control study of malignant melanoma among employees of the Lawrence Livermore National Laboratory.

During 1972 to 1977, the Lawrence Livermore National Laboratory (LLNL) experienced increased diagnosis of malignant melanoma among employees. In 1984, a report on the results of a case-control study of 39 cases concluded that occupational factors, including exposures to ionizing radiation and to chemicals, caused the excess incidence. The study reported here, based on results from 69 case-control pairs, re-examines the role of the occupational factors implicated by the earlier study in melanoma causation. Results from this study suggest that constitutional factors, including skin reactivity to sunlight, sunbathing frequency, and number of moles, explain most of the excess melanoma. Exposures to occupational factors, including ionizing radiation and chemicals, were found to be no different in cases than in controls.

Algorithms↗
PubMed1997

Successful coronary pace-termination of ventricular tachycardia during coronary angioplasty.

Coronary pacing has been performed to treat bradycardias occurring during percutaneous transluminal coronary angioplasty (PTCA) using an angioplasty guidewire. We describe a case of a 62-year-old man who developed ventricular tachycardia (VT) during PTCA. The tachycardia was successfully terminated by overdrive pacing via an angioplasty guidewire.

Angioplasty, Balloon, Coronary↗
PubMed1997

Health risk and behaviour of out-of-school 16-year-olds in New South Wales.

This study describes the health risks and health behaviour of a sample of 283 out-of-school 16-year-olds in New South Wales. We sampled study participants through the Commonwealth Employment Service offices in 1994 using a multistage sampling procedure. Of those surveyed, 129 responded to a letter inviting them to participate and 154 were recruited opportunistically. This paper describes the study methods and results for self-reported binge drinking, weekly use of tobacco and marijuana, sexual abuse, physical abuse, drink-driving, violence, and use of health services, by sex and method of recruitment. High rates of substance use were observed. Reported substance use in the out-of-school group was consistently higher than for 16-year-olds in school, except for binge drinking for girls recruited by letter. Of the out-of-school group, 34 per cent reported weekly use of tobacco, marijuana and also binge drinking. Boys were more likely to report drink-driving than girls (28 per cent and 13 per cent respectively). Having been in trouble with police ranged from 32 per cent for girls recruited by letter to 75 per cent for boys recruited opportunistically. A high proportion of girls reported sexual abuse (34 per cent of the 'letter' group and 41 per cent of the 'opportunistic' group). Overall, 87 per cent of respondents had used health services in the previous year. The results indicate that this is a disadvantaged group of young people who are an important target for health service provision and interventions.

Adolescent↗
PubMed1997

Molecular and phenotypic analysis of Candida dubliniensis: a recently identified species linked with oral candidosis in HIV-infected and AIDS patients.

The discovery and characterisation of a novel species of Candida, termed Candida dubliniensis, associated with oral candidosis in HIV-infected individuals is described. These organisms share several phenotypic characteristics in common with Candida albicans and Candida stellatoidea, including the ability to produce germ tubes and chlamydospores. However, in contrast to these latter two species, C. dubliniensis isolates produce abundant chlamydospores, which are often arranged in contiguous pairs, triplets and other multiples suspended from a single suspensor cell. They belong to C. albicans serotype A and exhibit atypical substrate assimilation profiles. Genomic DNA fingerprinting analysis with the C. albicans-specific probe 27A and five different oligonucleotide probes consisting of short repeat sequence-containing motifs, demonstrated that C. dubliniensis has a distinct genomic organisation relative to C. albicans and C. stellatoidea. This was confirmed by karyotype analysis and random amplified polymorphic DNA (RAPD) analysis. Comparison of 500 bp of the V3 variable region of the large ribosomal subunit genes from 14 separate C. dubliniensis isolates and the corresponding sequences from C. albicans, C. stellatoidea, C. tropicalis, C. glabrata, C. parapsilosis, C. kefyr and C. krusei demonstrated that the C. dubliniensis isolates formed a homogenous cluster (100% similarity), representing a discrete taxon within the genus Candida that was significantly different from the other species analysed.

AIDS-Related Opportunistic Infections↗
PubMed1997

Determination of penicillin susceptibility of Streptococcus pneumoniae using the polymerase chain reaction.

AIM: To develop a polymerase chain reaction (PCR) based method to detect penicillin susceptibility in isolates of Streptococcus pneumoniae (SP). METHOD: PCR primers were designed to amplify differential nucleotide sequences of the penicillin-binding protein (PBP) genes 2b, 2x, and 1a in penicillin susceptible and resistant strains of SP. Primers derived from the PBP 2x and 2b genes were designed to amplify products from penicillin susceptible S pneumoniae (PSSP), whereas primers derived from the PBP 1a gene were designed to amplify gene sequences of penicillin resistant S pneumoniae (PRSP). RESULTS: Two hundred and thirty clinical isolates of SP from the USA, UK, Kenya, Romania, and the Kingdom of Saudi Arabia were tested. Of the isolates, 116 were penicillin susceptible, 65 were intermediately resistant, and 49 were highly resistant. PCR identified 108 (93%) of 116 of PSSP isolates, 55 (85%) of 65 intermediately resistant isolates, and all of the 49 highly resistant isolates of SP. The susceptibility of 16 (7%) isolates could not be determined using PCR. All of these 16 isolates had a minimum inhibitory concentration (MIC) of penicillin < 1 mg/l. None of the highly resistant isolates was identified as penicillin susceptible by PCR, although two of the isolates with intermediate resistance (MIC = 0.125 mg/l) were. CONCLUSION: Using primers that differentially identify the genotypes of susceptible and resistant strains of SP, PCR provides a rapid method for determining the penicillin susceptibility of SP isolates and could potentially be used for testing clinical samples.

Bacterial Proteins↗
PubMed1997

Direct estimates of prevalent HIV infection in adults in England and Wales for 1991 and 1993: an improved method.

OBJECTIVE: To estimate the number of prevalent HIV infections in England and Wales at the end of 1991 and 1993. METHOD: A direct method was used whereby population estimates derived from the National Survey of Sexual Attitudes and Lifestyle (NATSAL) and prevalence data from the Unlinked Anonymous HIV Prevalence Monitoring Programme (UAPMP) were combined to produce estimates of the number of adults infected and alive in the population. RESULTS: In the population of England and Wales the numbers of prevalent infections for defined transmission categories, at the end of 1993, were as follows: 12,600 through sex between men, 2500 through injecting drug use, and 6900 through heterosexual intercourse. The overall estimate was 22,800 HIV seropositive individuals. CONCLUSIONS: The direct method attempts to provide an estimate of the number of HIV infections using population based survey data. These estimates are consistent with other approaches using independent methods. Such methods are essential for inferring recent HIV incidence, projecting future AIDS cases, and for healthcare planning.

Adolescent↗