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Biomedical subjects

A David

Publications and source records attributed to A David.

At least 91 records · Page 5Linked to original sources
PubMed2000

Polyherbal formulations with wide spectrum antimicrobial activity against reproductive tract infections and sexually transmitted pathogens.

PROBLEM: Recent reports indicate high incidence of genital infections, most of which are sexually transmitted. Although specific drugs and antibiotics are available for some, a safe spermicidal formulation with wide spectrum antimicrobial action would be a desirable addition to the presently available spermicides. METHODS: Formulations at different dilutions were tested in culture systems on standard strains and clinical isolates including some isolates resistant to drugs. The effect on (HSV)-2 and Chlamydia trachomatis was determined in vivo in progestin sensitized mice. The effect on HIV-1 was investigated in two standardized systems. RESULTS: Polyherbal cream inhibited the growth in culture of clinical isolates of Candida albicans, Candida krusei and Candida tropicalis. Both the polyherbal cream and the Praneem polyherbal pessary inhibited urinary tract Escherichia coli (including multidrug resistant strains), and Neisseria gonorrhoeae (including 2 strains resistant to penicillin). Both formulations manifested virucidal activity against HIV-1 at >2 and 50% dilutions (in two different test systems) on contact for 1-2 min. Intravaginal inoculation of the cream and the pessary suspensions before inoculation of the pathogen prevented lesions and vaginal transmission of HSV-2 and C. trachomatis in progestin sensitized mice. CONCLUSIONS: Polyherbal formulations have wide spectrum antibacterial, antifungal and antiviral effect against the tested sexually transmitted pathogens.

Animals↗
PubMed2000

Occupational risk factors for ill health in Gulf veterans of the United Kingdom.

OBJECTIVES: To study the association between occupational factors specific to the Armed Forces (rank, functional roles, Service, regular or reservist status and deployment factors) and symptomatic health problems in Gulf veterans, after sociodemographic and lifestyle factors have been accounted for. DESIGN: A postal cross sectional survey of randomly selected UK Gulf veterans was conducted six to seven years after the Gulf conflict. Physical ill health was measured using the Fatigue Questionnaire and a measure of the Centers for Disease Control and Prevention (CDC) multi-symptom syndrome. Psychological ill health was measured using the General Health Questionnaire and a post-traumatic stress measure. SETTING: Population of servicemen who were serving in the UK Armed Forces during the Gulf conflict between 1 September 1990 and 30 June 1991. PARTICIPANTS: 3297 Gulf veterans. MAIN RESULTS: In multivariate logistic regression, there was an inverse relation between higher rank and psychological and physical ill health (test of trend: General Health Questionnaire, p=0.004; post-traumatic stress, p=0.002; fatigue, p=0.015; CDC case, p=0.002). Having left the Armed Forces was associated with a two to three times increase in reporting ill health. Of the deployment factors, there was a weak association between being deployed as an individual reinforcement in a combat role and post-traumatic stress but there was no association between receiving pre-deployment training or post-deployment leave and ill health. Marital status and smoking were associated with psychological and physical ill health. CONCLUSIONS: Rank was the main occupational factor associated with both psychological and physical ill health in Gulf veterans. This may parallel the associations between socioeconomic status and morbidity in civilian populations. Ill health seems to be greater in those who return to civilian life. Sociodemographic factors also seem to be important in ill health in Gulf veterans.

Adult↗
PubMed2000

Viral vectors for gene delivery and gene therapy within the endocrine system.

The transfer of genetic material into endocrine cells and tissues, both in vitro and in vivo, has been identified as critical for the study of endocrine mechanisms and the future treatment of endocrine disorders. Classical methods of gene transfer, such as transfection, are inefficient and limited mainly to delivery into actively proliferating cells in vitro. The development of viral vector gene delivery systems is beginning to circumvent these initial setbacks. Several kinds of viruses, including retrovirus, adenovirus, adeno-associated virus, and herpes simplex virus, have been manipulated for use in gene transfer and gene therapy applications. As different viral vector systems have their own unique advantages and disadvantages, they each have applications for which they are best suited. This review will discuss viral vector systems that have been used for gene transfer into the endocrine system, and recent developments in viral vector technology that may improve their use for endocrine applications - chimeric vectors, viral vector targeting and transcriptional regulation of transgene expression.

Endocrine System↗
PubMed2000

Explicit and implicit neural mechanisms for processing of social information from facial expressions: a functional magnetic resonance imaging study.

The processing of changing nonverbal social signals such as facial expressions is poorly understood, and it is unknown if different pathways are activated during effortful (explicit), compared to implicit, processing of facial expressions. Thus we used fMRI to determine which brain areas subserve processing of high-valence expressions and if distinct brain areas are activated when facial expressions are processed explicitly or implicitly. Nine healthy volunteers were scanned (1.5T GE Signa with ANMR, TE/TR 40/3,000 ms) during two similar experiments in which blocks of mixed happy and angry facial expressions ("on" condition) were alternated with blocks of neutral faces (control "off" condition). Experiment 1 examined explicit processing of expressions by requiring subjects to attend to, and judge, facial expression. Experiment 2 examined implicit processing of expressions by requiring subjects to attend to, and judge, facial gender, which was counterbalanced in both experimental conditions. Processing of facial expressions significantly increased regional blood oxygenation level-dependent (BOLD) activity in fusiform and middle temporal gyri, hippocampus, amygdalohippocampal junction, and pulvinar nucleus. Explicit processing evoked significantly more activity in temporal lobe cortex than implicit processing, whereas implicit processing evoked significantly greater activity in amygdala region. Mixed high-valence facial expressions are processed within temporal lobe visual cortex, thalamus, and amygdalohippocampal complex. Also, neural substrates for explicit and implicit processing of facial expressions are dissociable: explicit processing activates temporal lobe cortex, whereas implicit processing activates amygdala region. Our findings confirm a neuroanatomical dissociation between conscious and unconscious processing of emotional information.

Adult↗
PubMed2000

Microsatellite haplotypes associations with 5 CFTR mutations in "Grande Brière", an isolate located in southern Brittany.

The variability at three microsatellites in the Cystic Fibrosis Transmembrane Conductance Regulator Gene (CFTR) locus has been studied for frequent mutations encountered in an isolated population of "Grande Brière", a small region located in Southern Brittany. Fluorescent multiplex PCR of these microsatellites were assayed in 16 Cystic Fibrosis (CF) families carrying 5 different mutations. The four most frequent haplotypes on df508 chromosomes were the same as those found in Northern France and Europe but the distribution of these haplotypes provides new enlightenment on the population origin of this insular community.

Cystic Fibrosis Transmembrane Conductance Regulato↗
PubMed1999

Cytokine therapy: a natural alternative for disease control.

Disease control in food production animals is normally mediated through the use of vaccines, chemicals and antibiotics. However, the extensive use of antibiotics and chemicals in livestock has resulted in environmental and human health concerns, particularly with regard to the emergence of drug-resistant bacteria in the food chain. In fact, the World Health Organisation (WHO) has now urged meat producers to use environmentally-friendly alternative methods to control disease. Cytokines, as natural mediators of the immune response, offer exciting alternatives to conventional therapeutics. The utilisation of cytokines is becoming more feasible with the recent cloning of a number of cytokine genes. Since the chicken's immune system is similar to that of mammals, they offer an attractive model system with which to study the effectiveness of cytokine therapy in the control of disease in intensive livestock. In this report we will review our recent studies on the therapeutic potential of chicken interferon gamma (ChIFN-gamma) as a vaccine adjuvant and a growth promoter.

Adjuvants, Immunologic↗
PubMed1999

Health of UK servicemen who served in Persian Gulf War.

BACKGROUND: Various symptoms in military personnel in the Persian Gulf War 1990-91 have caused international speculation and concern. We investigated UK servicemen. METHODS: We did a cross-sectional postal survey on a random sample of Gulf War veterans (Gulf War cohort, n=4248) and, stratified for age and rank, servicemen deployed to the Bosnia conflict (Bosnia cohort, n=4250) and those serving during the Gulf War but not deployed there (Era cohort, n=4246). We asked about deployment, exposures, symptoms, and illnesses. We analysed men only. Our outcome measures were physical health, functional capacity (SF-36), the general health questionnaire, the Centers for Disease Control and Prevention (CDC) multisymptom criteria for Gulf War illness, and post-traumatic stress reactions. FINDINGS: There were 8195 (65.1%) valid responses. The Gulf War cohort reported symptoms and disorders significantly more frequently than those in the Bosnia and Era cohorts, which were similar. Perception of physical health and ability were significantly worse in the Gulf War cohort than in the other cohorts, even after adjustment for confounders. Gulf War veterans were more likely than the Bosnia cohort to have substantial fatigue (odds ratio 2.2 [95% CI 1.9-2.6]), symptoms of post-traumatic stress (2.6 [1.9-3.4]), and psychological distress (1.6 [1.4-1.8]), and were nearly twice as likely to reach the CDC case definition (2.5 [2.2-2.8]). In the Gulf War, Bosnia, and Era cohorts, respectively, 61.9%, 36.8%, and 36.4% met the CDC criteria, which fell to 25.3%, 11.8%, and 12.2% for severe symptoms. Potentially harmful exposures were reported most frequently by the Gulf War cohort. All exposures showed associations with all of the outcome measures in the three cohorts. Exposures specific to the Gulf were associated with all outcomes. Vaccination against biological warfare and multiple routine vaccinations were associated with the CDC multisymptom syndrome in the Gulf War cohort. INTERPRETATION: Service in the Gulf War was associated with various health problems over and above those associated with deployment to an unfamiliar hostile environment. Since associations of ill health with adverse events and exposures were found in all cohorts, however, they may not be unique and causally implicated in Gulf-War-related illness. A specific mechanism may link vaccination against biological warfare agents and later ill health, but the risks of illness must be considered against the protection of servicemen.

Adult↗
PubMed1999

Is there a Gulf War syndrome?

BACKGROUND: UK veterans of the Gulf War report more ill health than servicemen who were not deployed to the Gulf War. We investigated whether the pattern of symptom reporting by veterans of the Gulf War differed from that in active servicemen who had not fought in the Gulf War or who had fought in other conflicts. METHODS: We used a population-based cross-sectional design. We sent a standardised survey that asked about 50 physical symptoms to three UK military cohorts; men who had served in the Gulf War, those who had served in the Bosnia conflict, and men who had been in active service but not deployed to the Gulf War (Era cohort). We used exploratory factor analysis to identify underlying factors and describe the factor structure of the symptoms reported in the Gulf War cohort. Confirmatory factor analysis was used to test the fit of this factor structure in the Bosnia and Era cohorts. FINDINGS: Three factors in the Gulf War cohort together accounted for about 20% of the common variance. We labelled the factors mood, respiratory system, and peripheral nervous system, according to the symptoms that loaded on to them. In the confirmatory factor analysis, the factor structure identified in the Gulf War cohort fitted reasonably well in the Bosnia and Era cohorts. INTERPRETATION: Although results from complex modelling procedures need to be interpreted with caution, our findings do not support a unique Gulf War syndrome. The mechanisms behind increased self-reporting of symptoms need further investigation.

Bosnia and Herzegovina↗
PubMed1999

The effect of parabens in a mouthwash and incorporated into a sustained release varnish on salivary bacteria.

OBJECTIVES: The purpose of this study was to evaluate the antimicrobial efficacy of parabens, in a mouthwash and in a slow release device, against cariogenic bacteria in the oral cavity. METHODS: Parabens were formulated in a mouthwash or in a topical slow release varnish preparation. In two separate studies, volunteers were asked to use the mouthwash or the slow release varnish applied in a personal night guard device. The levels of mutans streptococci (MS), Lactobacilli (LB) and total cultivated bacteria were measured before and after using the mouthwash or the slow release varnish. RESULTS: The mouthwash containing parabens had a minor and a short-term effect on MS and LB counts in human saliva. The use of slow release varnish containing parabens, applied in a night guard, had a prolonged antibacterial effect on both MS and LB counts. CONCLUSIONS: Parabens in a mouthwash had little effect on oral bacteria counts; however, paraben in the slow release device had a significant and an extended effect in reducing oral bacteria. Although substantial reductions in oral bacterial counts were recorded after the use of parabens in a slow release device, this effect could probably be enhanced by an improved pharmaceutical formulation.

Administration, Topical↗
PubMed1999

Brachmann-de Lange syndrome: a cause of early symmetric fetal growth delay.

Brachmann-de Lange syndrome is characterized by pre- and postnatal growth retardation, microbrachycephaly, hirsutism, various visceral and limb anomalies and a typical face. A sonographic prenatal diagnosis at mid-trimester is reported in a case of severe, symmetrical fetal growth delay at 20 weeks gestation, with a thickened skin on the forehead, a small nose and a marked depressed nasal bridge, a long philtrum, micrognathia and a persistently flexed right forearm, with a single bone associated to oligodactyly. Due to the severe mental impairment with a commonly estimated intelligence quotient under 60, the pregnancy was terminated after parental consent.

Adult↗
PubMed1999

A cDNA from tobacco codes for an inhibitor of virus replication (IVR)-like protein.

We have shown previously that localization of tobacco mosaic virus (TMV) in tobacco is associated with a ca. 23 kDa protein that inhibits replication of several plant viruses. This protein, named 'inhibitor of virus replication' (IVR), was purified from the medium of TMV-inoculated protoplasts derived from Nicotiana tabacum cv. Samsun NN. IVR was shown to be present also in induced-resistant leaf tissue of N. tabacum cv. Samsun NN. We prepared an expression cDNA library from such induced-resistant tissue and screened it with a polyclonal antibody raised against the IVR protein. A 1016 bp clone (named NC330) containing a 597 bp open reading frame, coding for a 21.6 kDa polypeptide, was isolated. The NC330 clone hybridized with RNA from induced-resistant tissue from N. tabacum cv. Samsun NN but not with RNA from non-induced tissue. Likewise, it did not hybridize with RNA from infected or uninfected tissue of N. tabacum cv. Samsun nn. Similarly, the NC330 cloned probe hybridized with the RT-PCR products from RNA of the induced-resistant tissue only. In Southern blot hybridization the NC330 DNA probe detected several genomic DNA fragments in both N. tabacum cv. Samsun NN and Samsun nn. The size of the DNA fragments differed in Samsun NN and Samsun nn. We suggest that DNA encoding the IVR-like protein is present in resistant and susceptible N. tabacum genotypes, but is expressed only in NN. We have inserted the NC330 into the expression vector pET22b and a 21.6 kDa protein was produced in Escherichia coli that reacted in immunoblots with the IVR antibody. This protein greatly reduced replication of TMV in N. tabacum cv. Samsun nn leaf disk assays.

Amino Acid Sequence↗
PubMed1999

Hydrometrocolpos and polydactyly: a common neonatal presentation of Bardet-Biedl and McKusick-Kaufman syndromes.

McKusick-Kaufman syndrome (MKKS) is a rare, recessively inherited syndrome reported mainly in young children and is characterised by vaginal atresia with hydrometrocolpos, postaxial polydactyly, and congenital heart defect. Bardet-Biedl syndrome (BBS) is the generic name for a genetically heterogeneous group of autosomal recessive disorders characterised by retinal dystrophy or retinitis pigmentosa (appearing usually between 10 and 20 years of age), postaxial polydactyly, obesity, nephropathy, and mental disturbances, or, occasionally, mental retardation. Typically, MKKS is diagnosed (and reported) in very young children, whereas the diagnosis of BBS often is delayed to the teenage years. We report here a series of nine patients diagnosed in infancy with MKKS because of the presence of vaginal atresia and postaxial polydactyly, who later developed obesity and retinal dystrophy, thus turning out to be instances of BBS. The overlap of BBS and MKKS is a real diagnostic pitfall and its importance has to be stressed, for genetic counselling, for clinical management and follow up, and for molecular approaches. The diagnosis of MKKS should be considered with caution in all published cases described exclusively in the neonatal period and in those with mental retardation. We strongly recommend all children seen in infancy with a diagnosis of MKKS to be re-evaluated for RP and other signs of BBS.

Abnormalities, Multiple↗
PubMed1999

[Protective effect of an apoptosis inhibitor in a new model of hepatitis induced by interleukin-4 in the rat].

OBJECTIVES: Interleukin-4 is a cytokine with pleiotropic effects on many cells. The effects of its expression on the liver remain unclear. To obtain organ-localized cytokine expression and analyze its effect on the liver, recombinant adenovirus with coding sequences of interleukin-4 were transduced to rat livers. METHODS: Adenovirus with coding sequences of rat interleukin-4 were injected into the portal vein of Wistar rats. Microscopic examination of the liver was performed. The effects of interleukin-4 were confirmed in vitro on primary cultured rat hepatocytes. The same analysis was performed after intraperitoneal injection of l'YVADcmk, an inhibitor of the interleukin 1 converting enzyme. RESULTS: Interleukin-4 expression due to the recombinant adenovirus produced dose-related, potentially lethal, severe hepatitis. This hepatitis was characterized by a leucocyte infiltrate mainly composed of eosinophilic polymorphonuclear and mast cells with numerous apoptotic hepatocytes. Intraperitoneal injection of YVADcmk decreased hepatocyte apoptosis and biological hepatitis and prevented death. CONCLUSION: These results suggested that YVADcmk might be used in fulminant hepatitis in which apoptosis is predominant.

Acute Disease↗
PubMed1999

[Trichothiodystrophy: progresssive manifestations].

INTRODUCTION: Trichothiodystrophy is an autosomal recessive genodermatosis associating congenital dysplasia of the hair and neuroectodermal defects. Clinical expression is variable, although abnormalities are generally noted from birth. We report trichothiodystrophy in two brothers with the same phenotype who presented unusual progressive manifestations. OBSERVATIONS: Case 1: A six-year-old boy was seen for vesicular blisters due to photosensitization. Clinical examination showed dry, brittle, unmanageable hair, discrete koilonychia-type nail defects and an ichthyosiform state. The teeth were normal. In addition to psychomotor retardation, the patient presented a dysmorphic syndrome (poorly rimmed low-set ears; thick, triangular upper lip; scaphocephalic skull; short hands) and congenital bilateral cataract. The diagnosis of trichothiodystrophy was confirmed by a study of DNA repair after exposure to ultraviolet light. A repair defect was found similar to that in xeroderma pigmentosum group D. The patient experienced a worsening of psychomotor retardation and episodes of hair loss with edema and inflammation of the scalp resulting from infections. He also showed marked asthenia which resolved spontaneously within a few months. Case 2: The other brother, born as a collodion baby, presented the same clinical picture (cutaneous, exoskeletal, dysmorphic), including congenital bilateral cataract, photosensitivity and a parenchymatous blister-type pulmonary lesion probably secondary to bronchiectasis. The patient's cutaneous state progressively improved. He was seen at six years of age for an episode of inflammatory edema of the scalp with hair loss. Within six months, all of the hair redrew. The diagnosis of trichothiodystrophy was confirmed by a DNA repair defect after exposure to ultraviolet light. DISCUSSION: Trichothiodystrophy is clinically associated with photosensitivity (P), ichthyosis (I), dry, brittle hair (B), intellectual impairment (I), decreased fertility (D) and short stature (S), which accounts for the acronym PIBIDS or IBIDS syndrome, depending on whether photosensitivity is involved or not (actually in about 50 p. 100 of cases). Other possibly associated features include ungueal dysplasias, bilateral cataract, defective teeth, dysmorphic disorders predominant in the ears, neurologic disorders, pulmonary bronchiectasis and recurrent infections. The two cases presented here were thus very symptomatologically complete. The two problems of current concern are psychomotor retardation and temporary hair loss as a result of infections. The latter has only been described once in the literature. This case was similar to ours since photosensitivity was involved. Analysis of DNA repair also showed a defect after exposure to ultraviolet light similar to that found in xeroderma pigmentosum group D. Thus, episodic hair loss could be a symptom characteristic of forms of trichothiodystrophy with a DNA repair defect. However, the explanation for this hair loss is not known. Other ectodermal dysplasias can be complicated by hair loss with superinfection, such as AEC syndrome (ankyloblepharon, ectodermal dysplasia, cleft palate).

Abnormalities, Multiple↗
PubMed1999

A new approach to restorative dentistry: fabricating ceramic restorations using CEREC CAD/CAM.

Ceramic materials provide an alternative when choosing a tooth-colored restoration. Currently, posterior composite restorations can be used to achieve esthetic restorations; however, they have many disadvantages with regard to wear, polymerization shrinkage, discoloration, marginal leakage, and technique sensitivity. The use of CEREC CAD/CAM enables the dentist to place feldspathic porcelain (Vitablocs Mark II) and machinable glass ceramic (Dicor MGC) restorations in a single visit. When compared to composite materials, these materials closely approximate the physical properties of enamel in compressive and tensile strength and wear resistance. This study evaluated 50 CEREC CAD/CAM restorations after 4 years in service. Restorations ranged from Class I to 7/8s crown preparations.

Adult↗