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Biomedical subjects

C Wood

Publications and source records attributed to C Wood.

At least 91 records · Page 5Linked to original sources
PubMed1999

Covert orienting of visual spatial attention in attention deficit hyperactivity disorder: does comorbidity make a difference?

Attentional performance in children with attention deficit hyperactivity disorder (ADHD) with and without comorbid disorders was examined using the Covert Orienting of Visuospatial Attention Task (COVAT) and the Continuous Performance Task (CPT). The relationship between these two tasks was also examined. The results showed no overall differences on the attention tasks between children with ADHD alone and those with ADHD plus other disorders. Compared to non-ADHD control children, children with ADHD showed a deficit in the disengage operation of covert visuospatial attention, suggesting a difficulty in the endogenous mode of orienting. The ADHD children also showed a general performance deficit on the CPT. Although there was a general slowing on both attention tasks in the ADHD group, there was no relationship between invalid cue effect sizes on the COVAT and the CPT measures. These results indicate that these two attention tasks may be tapping both similar and independent underlying cognitive processes in ADHD.

Journal Article↗
PubMed1998

Prevalence of renal stones in a population-based study with dietary calcium, oxalate, and medication exposures.

Little is known about the epidemiology of renal stones, in spite of the relative frequency of this painful condition. This population-based study examined reported renal stone diagnosis in 1,309 women aged 20-92 years to determine whether renal stones are associated with 1) food or water exposures or 2) lower bone mineral density and an increased likelihood of fractures. Results indicated a renal stone prevalence of 3.4%. The average age at diagnosis was 42 years. Renal stone formation was not associated with community of residence, hypertension, bone mineral density, fractures, high-oxalate food consumption, or ascorbic acid from food supplements. Women with renal stones consumed almost 250 mg/day less dietary calcium (p < 0.01) than did women without stones and had a lower energy intake (p < 0.04). The authors' findings do not support the hypothesis that increased dietary calcium is associated with a greater prevalence of renal stones, nor do they identify renal stones as a risk factor for low bone mineral density. Furthermore, lack of other identifiable environmental correlates and the relatively young age at initial diagnosis suggest that genetic components of renal stone formation need further study.

Adult↗
PubMed1998

Effect of intramural, subserosal, and submucosal uterine fibroids on the outcome of assisted reproductive technology treatment.

OBJECTIVE: To investigate the effect of subserosal, intramural, and submucosal fibroids on the outcome of assisted reproductive technology (ART) treatment. DESIGN: A retrospective comparative study. SETTING: A tertiary referral center for infertility. PATIENT(S): Treatment outcome of 106 ART cycles in 88 patients with uterine fibroids (33 subserosal, 46 intramural without cavity distortion, and 9 submucosal) was compared with that of 318 ART cycles in age-matched patients without fibroids. INTERVENTION(S): Controlled ovarian hyperstimulation and ART. MAIN OUTCOME MEASURE(S): Findings on transvaginal uterine ultrasonography performed before the initiation of treatment and pregnancy and implantation rates. RESULT(S): The pregnancy rates per transfer were 34.1%, 16.4%, 10%, and 30.1% in the patients with subserosal fibroids, intramural fibroids, submucosal fibroids and no fibroids, respectively. The implantation rates were 15.1%, 6.4%, 4.3%, and 15.7%, respectively. Both rates were significantly lower in patients with intramural fibroids than in those with subserosal fibroids or no fibroids. CONCLUSION(S): Pregnancy and implantation rates were significantly lower in the groups of patients with intramural and submucosal fibroids, even when there was no deformation of the uterine cavity. Pregnancy and implantation rates were not influenced by the presence of subserosal fibroids. Surgical or medical treatment should be considered in infertile patients who have intramural and/or submucosal fibroids before resorting to ART treatment.

Adult↗
PubMed1998

Factors affecting the success of human blastocyst development and pregnancy following in vitro fertilization and embryo transfer.

OBJECTIVE: To determine the factors affecting blastocyst development and pregnancy after IVF and ET. DESIGN: Retrospective analysis of data arising from a clinical trial. SETTING: Private in vitro fertilization clinic. PATIENT(S): Fifty-six patients aged < or = 40 years, undergoing IVF procedures for infertility, recruited specifically for blastocyst transfer. INTERVENTION(S): All zygotes were cultured to days 5 or 6 after insemination, and one to four of the most advanced blastocysts were transferred to the patient's uterus. MAIN OUTCOME MEASURE(S): Development of zygotes to blastocysts in vitro and pregnancy and implantation rates after ET. RESULT(S): Fifty-one percent of all zygotes developed to blastocysts. Significant positive correlation between the number of blastocysts formed was observed with the number of oocytes, pronuclear zygotes, and eight-cell embryos formed. There was a negative correlation with male factor infertility. By day 5 or 6, 93% of the patients had at least one blastocysts, and the clinical pregnancy rate per transfer was 43% and the implantation per embryo transferred was 25%. No other clinical factor significantly affected the number of blastocysts formed, pregnancy rate, or implantation rate. CONCLUSION(S): The numbers of oocytes, zygotes, and normally developing embryos in culture significantly affects the production of blastocysts in vitro. Male infertility significantly reduces blastocyst production. The number and the quality of the blastocysts transferred significantly influences clinical pregnancy rate.

Adult↗
PubMed1998

Localization of human herpesvirus type 8 (HHV-8) in the Kaposi's sarcoma tissues and the semen specimens of HIV-1 infected and uninfected individuals by utilizing in situ polymerase chain reaction.

Kaposi's sarcoma (KS) is a form of skin cancer, most commonly found in individuals suffering from acquired immunodeficiency syndrome, or AIDS. However, before the worldwide infection of human immunodeficiency virus (HIV), the rare occurrence of KS was confined to two distinct groups of individuals. In the Western world, the classical form of KS was often found in older men (60-70 years of age) from the Mediterranean area. Another form called endemic KS, was found in Equatorial Africa. Currently, the most common cases of KS are found in individuals suffering from AIDS. This is called AIDS-associated KS. Between 30 and 40% of male, homosexual AIDS patients suffer from AIDS-associated KS. KS is also occasionally diagnosed in transplant patients receiving immunosuppressive drugs (to keep their body from rejecting the foreign organ). As opposed to cases of classic and endemic KS, the KS in AIDS patients progresses very quickly, often with a fatal outcome. Human herpesvirus type 8 (HHV-8) has been implicated as the cause of Kaposi's sarcoma (KS), but the exact connection of the virus to the neoplasm is not known. The virus has been detected within the sarcoma skin lesions, but has additionally been seen in peripheral blood cells, semen samples, prostate tissue, and other types of soft tissue tumors. In this study, we evaluated HHV-8 within the skin lesion of KS as well as in semen specimens obtained from HIV-1 infected and uninfected specimens from HIV-1-seronegative individuals. Twenty-eight tissue samples representing AIDS-associated, endemic KS, and six non-KS patients were collected for observation from different centers throughout the world. The tissues were examined utilizing in situ polymerase chain reaction (ISPCR) and hybridization to identify and localize the herpesvirus within the KS lesions. With the use of the sensitive ISPCR technique, HHV-8 DNA was detected in the spindle cells within the nodular skin lesions, as well as in the microvascular endothelial cells which line small vessels within the lesions in all forms of KS. In addition, we analysed semen specimens from HIV-1 infected and uninfected men, our analyses revealed that HHV-8 was present in the significant proportions of the HIV-1-infected-individuals' sperm, as well as in the mononuclear cells of the semen specimens. HHV-8 DNA was demonstrated, by ISPCR, in KS lesions as well as in seminal mononuclear cells and sperm of significantly high proportion of HIV-1-infected men. What role the presence of HHV-8 in the sperm cells plays in the sexual transmission of this herpesvirus will require further study. However, the reports which demonstrate that KS lesions can develop in infants of only a few weeks of age, increases the possibility that this agent may be vertically transmitted. It can be suggested that HHV-8 is relatively ubiquitous and its frequency increases with the increasing immunosuppression.

HIV Infections↗
PubMed1998

Endoscopic treatment of uterine fibroids.

Endoscopic surgery is able to replace most abdominal operations in the surgical treatment of uterine leiomyomas. The use of gonadotrophin hormone-releasing hormone analogues, arterial embolization, hysteroscopy, new techniques of morcellation, laparo-vaginal gasless laparoscopy and laparoscopic mini-laparotomy have enabled the avoidance of laparotomy incisions in most patients. The previous disadvantages of laparoscopy, namely a prolonged operating time, excessive bleeding and inadequate closure, have been overcome. Case and controlled studies have demonstrated the effectiveness of endoscopy in fibroid treatment. The surgical techniques require advanced endoscopic training.

Electrocoagulation↗
PubMed1998

A technique for establishing the identity of 'isolated' fossil hominin limb bones.

Associated skeletons, which are specimens preserving more than one body part from the same individual, are especially important for taxonomic and functional analyses. This study concentrates on the subset of associated skeletons which preserve the reciprocal surfaces of a joint. It uses laser scanning to explore whether the shapes of the reciprocal surfaces of a joint of an individual are significantly more congruent than the surfaces of randomly-matched pairings taken from the same species. Laser scanning was used to capture the distal articular surface of the left tibia of OH35 and the trochlear articular surface of the talus of OH8, both from Bed I, Olduvai Gorge, Tanzania. The degree of congruency between those articular surfaces was tested against the congruency of the talocrural joint of AL 288-1 (Australopithecus afarensis), and the congruency of both associated and randomly-matched talocrural joints of modern humans, chimpanzees and gorillas. The results suggest that OH35 and OH8 do not come from the same individual and may not come from the same species. Although this analysis leaves open the taxonomic affinity of OH35, it demonstrates the potential of laser scanning for capturing 3D data in palaeoanthropology. It also demonstrates the potential for using the relative congruency of reciprocal joint surfaces as a test of the likelihood that isolated limb bones are components of a single individual.

Animals↗
PubMed1998

Seroprevalence of human herpesvirus 8 among Zambian women of childbearing age without Kaposi's sarcoma (KS) and mother-child pairs with KS.

The seroprevalence of human herpesvirus 8 (HHV-8) among a group of Zambian women of reproductive age and among mother-child pairs in which either one of them has Kaposi's sarcoma (KS) was determined. A cross-sectional group of 378 pregnant women was randomly recruited into the study, and 183 (48.4%) had HHV-8 antibodies. Among the human immunodeficiency virus (HIV)-1-infected women, 51.1% were HHV-8-seropositive, whereas of HIV-1-negative women, 47.3% were HHV-8-seropositive. In addition, 21 women index patients with KS and 5 young children index patients with KS were studied. All children with KS had mothers who were HHV-8-seropositive, while not all children whose mothers had KS were infected with HHV-8. Our study suggests that there is a high HHV-8 seroprevalence among Zambian women, and the rate is almost the same in HIV-1-positive and -negative women. This high seroprevalence may be a contributing factor toward the increased frequency of KS in this population.

Adolescent↗
PubMed1998

Human herpesvirus 8 as a potential sexually transmitted agent in Honduras.

The seroprevalence of human herpesvirus 8 (HHV-8) was studied in 326 human immunodeficiency virus (HIV)-positive and -negative persons from Honduras; women constituted 77% (n = 251) of the subjects. Sera were tested for lytic HHV-8 antibodies by an IFA, and positive samples were confirmed by a radioimmunoprecipitation assay. Of the 326 persons tested, 58 (17.8%) had HHV-8 antibodies. Among the HIV-infected women, 22.7% were seropositive; 11.3% of the HIV-negative women were seropositive. HHV-8 seroprevalence was almost four times higher in HIV-positive female commercial sex workers (36%) than in HIV-negative female non-commercial sex workers (9.9%; odds ratio = 3.8, 95% confidence interval = 1.1-13; P = 0.01), suggesting that commercial sex work is a risk factor for HHV-8 infection. In the men studied, the overall HHV-8 seroprevalence was 22.6%, with a seropositivity rate of 28% for HIV-positive men compared with 12% for HIV-negative men.

AIDS-Related Opportunistic Infections↗
PubMed1998

Evolution of a culture protocol for successful blastocyst development and pregnancy.

A cell-free culture system was designed for human embryo development to the blastocyst stage by testing a range of culture conditions in a series of protocols. The culture system that was evolved has a brief 1 h exposure to spermatozoa and then culture of the pronucleate zygote for 2 days in IVF-50 medium. Two or three embryos were cultured together in 20 microl microdrops of medium under oil. Embryos were then regrouped and two or three at a similar stage were cultured together in 50 microl microdrops of Gardner's G2 medium under oil from days 3 to 5. Embryos were transferred to fresh G2 medium on day 5 and cultured for a further 1 or 2 days (day 6 or 7). No serum was used in any of the cultures. The embryo transfer medium and G2 medium were supplemented with human serum albumin. The zonae of all blastocysts to be transferred to patients were completely removed enzymatically. Using this protocol, 52% of zygotes developed to blastocysts and 34 out of 35 patients treated received 82 blastocysts and 11 morulae on day 5 or 6. Twenty-one fetal sacs with positive heartbeats (23% implantation rate) were detected in 13 ongoing pregnancies (38% pregnancy rate/transfer or 37%/patient treated). We anticipate that further improvements in embryo development and the selection of viable embryos can be achieved using this simple and effective culture system.

Adult↗
PubMed1998

Oocyte maturation.

Primary oocytes recovered from small and growing follicles of > or = 3 mm in the ovaries of untreated women, can be matured in vitro, will fertilize and develop in vitro, and when transferred to the patient, develop to term. However, the implantation rate of cleaved embryos has been disappointingly low and when embryos are allowed to develop beyond the 4-cell in vitro, retardation of development and blockage is frequently observed, with relatively few embryos developing to blastocysts. We have devised new culture systems for human embryos to enable high rates of development of in-vivo matured oocytes to blastocysts within 5-6 days of culture, and high implantation rates of these blastocysts when they are transferred to the patients' uterus. These culture systems are now being used for in-vitro matured oocytes. In order to determine whether embryo developmental competence could be improved, a number of factors were examined. Treatment of patients with pure follicle stimulating hormone (FSH) early in the follicular phase, or treatment with oestrogen prior to oocyte recovery, had no apparent effect on any parameters of oocyte developmental competence. There was no indication that a medium made specifically for human oocyte maturation improved oocyte developmental competence. Nuclear and cytoplasmic changes in oocytes matured in vitro appear to be similar to that in vivo, although some lack of synchronization in completing maturation is evident. It is possible that follicles of < 10 mm diameter in the human contain developmentally-incompetent oocytes. However, the development to term and birth of normal babies from germinal vesicle stage oocytes recovered from small follicles and matured in vitro, suggests that further research will identify the factors necessary to improve embryo developmental competence. The application of immature oocyte collection (IOC) and in vitro maturation (IVM) as an alternative to ovulation stimulation with high doses of gonadotrophins for in-vitro fertilization (IVF), remains a priority for research in human medicine.

Animals↗
PubMed1998

Screening for diabetic retinopathy using a non-mydriatic retinal camera in rural Victoria.

PURPOSE: To develop a screening programme for the early detection of diabetic retinopathy using non-mydriatic retinal photography. METHODS: A community based screening service was offered to all people with known diabetes mellitus in selected townships in the LaTrobe and Goulburn Valleys in Victoria. At the local examination centre, basic sociodemographic information was collected as well as details of previous use of eye care services for the early detection of diabetic retinopathy. The examination included visual acuity (VA), glycosylated haemoglobin level and Polaroid photographs of each fundus using a Canon CR5-45NM non-mydriatic retinal camera (Canon, Tochigiken, Japan). Dilating drops were not used. Photographs were subsequently reviewed and letters were sent to all participants (with copies to their general practitioners) with recommendations for appropriate follow up. RESULTS: A total of 1177 people with diabetes attended the screening service, which is estimated to be 40% of the total population with known diabetes in the study area. The mean age was 65 years (range 20-94 years); 559 (48%) people reported not having a dilated fundus examination within the past 2 years; 345 (29%) people had never had a dilated fundus examination. Of the 2354 eyes, 2126 (90%) of the photographs were gradable. A total of 704 people (60%) had normal VA and no evidence of diabetic retinopathy, 209 people (18%) had diabetic retinopathy, 101 people (9%) had evidence of other fundus pathology, 42 people (3%) had reduced acuity (< 6/18) in one or both eyes (with no fundus pathology evident) and 121 people (10%) had ungradable photographs in one or both eyes. CONCLUSIONS: The present study demonstrates the usefulness of a screening programme with non-mydriatic retinal photography as an adjunct to current eye care services for the early detection of diabetic retinopathy.

Adult↗
PubMed1998

The misplace of litigation in medical practice.

Medical decision-making is based upon mathematical probability in determining the significance of variables involved. Truth is often not absolute and medical decisions often require reconsideration of information, reanalysis and possible change. Litigation based upon error negates the ordinary practice of medicine. Error is intrinsic to all human behaviour and contributed to by uncertainty concerning precision in diagnosis and treatment of some diseases, mood change affecting ability to process cognitive and analytic function, and adverse work environment. Error is an important process in learning and providing it is recognized and fully admitted is a creative process providing opportunity for improving medical practice. Litigation is based on proof of negligence. Negligence is defined as carelessness, which is a rare cause of human and medical errors. The law confuses error with negligence; error should not be the basis for litigation. Litigation based on error is counter-productive to the best practice and improvement of clinical medicine. The assessment of errors and negligence is limited by the method of choice of medical experts, the adversarial system often ignoring the intermediate position in favour of a yes-no answer, the selection of experts to favour the desired result rather than the real situation, the method of questioning of witnesses which discourages explanation and creative solution of disagreement, and the hierarchical system which does not allow exploration of the issues and creative solutions. The basis for financial compensation for ill health is relevant when this assists the sufferer to cope with the ill health. The ethical basis for compensation when ill health results from error by health care workers is not more valid than ill health resulting from biological or environmental factors. Human error is common normal behaviour, while biological and environmental causes of ill health are common errors of human biology and the environment. Unintentional human error should not be the basis of financial remuneration or punishment. This latter principle has been applied to all services between the customer and service supplier, which may lead to unnecessary mistrust, anxiety and alienation in modern society. Incapacity from injury or disablement is covered by damages payment in only a small percentage of permanent disability cases (1.5% in the U.K.). Universal insurance by government or private agencies e.g. as in motor accident insurance to include the 98% of the permanently disabled who are receiving no payment at present would be both preferable and fairer. The protection of barristers from litigation for negligence in court is based upon arguments that could apply to most other occupations, and are equally, if not more relevant to medicine. The legal system of settling claims for negligence by doctors needs to be replaced by an investigative system which seeks to explain the basis and cause of error, which would benefit the patient and the doctor, and improve medical practice. A creative process needs to replace a judgmental, rigid and punitive system. A committee involving specialist groups in selecting expert witnesses, a health counsellor and a patient representative may be most suitable. Criminal acts, where error is performed deliberately, assault or sexual misdemeanors, would still be subject to the common law.

Australia↗
PubMed1998

The place of laparoscopic surgery in surgical gynaecology.

This review was undertaken to ascertain whether the low usage of laparoscopic surgery in gynaecology resulted from unacceptable complication rates and long operating times. The safety and efficacy of laparoscopic surgery has been compared to that of laparotomy. Reports of controlled or comparative trials of laparoscopic gynaecological surgery for adhesions, infertility, ectopic pregnancy, oophorectomy, myomectomy and laparoscopically-assisted vaginal hysterectomy (LAVH) have been reviewed between 1984 and 1997. Although further multicentre controlled trials may improve the assessment of complication rates for both laparotomy and laparoscopy procedures, laparoscopy appears to be as safe as laparotomy and generally has the advantage of shorter hospital stay and earlier return to normal activities. Except for LAVH, operating times of laparoscopic surgery are similar to that of laparotomy.

Clinical Trials as Topic↗
PubMed1998

Inquiry into the potential value of an information pamphlet on consent to surgery to improve surgeon-patient communication.

OBJECTIVES: To find out how patients recently undergoing surgery experienced the consenting process and the response of these patients to a pamphlet on consent to surgery. To test the reaction of health professionals to the pamphlet. DESIGN: A pilot pamphlet was produced and a questionnaire was sent to patients inquiring about their consenting experience, and how the pamphlet might have helped them through the consent procedure. A pamphlet and a questionnaire were also sent to a random sample of the health professionals serving these patients. SUBJECTS: Patients and health professionals. RESULTS: 61% of patients returned the questionnaire. Knowledge about the consent procedure was shown to be limited. 49% were unaware that they had the right to insist that the surgeon could only perform the specified operation and nothing more. 83% were unaware that they could add something in writing to the consent form before signing. 28% of health professionals returned their questionnaire, most of whom thought that the pamphlet provided a useful contribution to surgeon-patient communication. CONCLUSION: Evidence shows that patients are not well informed about consenting to surgery and further information would provide much needed guidance on understanding their role in the consent procedure. The low response from the health professional study is perhaps an indication that at present this is an issue which is not seen as a priority.

Comprehension↗
PubMed1998

Cerebral aneurysmal arteriopathy in childhood AIDS.

OBJECTIVE: To identify cerebral aneurysmal arteriopathy in children with longstanding AIDS. BACKGROUND: Five cases are described from the authors' experience, and eight additional cases are reviewed from the literature. Details are presented in regard to the clinical picture as well as brain imaging with cerebral angiography and magnetic resonance angiography in some cases. Autopsy information is available in four cases, including one of the authors' patients. RESULTS: Seven patients acquired HIV infection perinatally, five patients were infected by blood transfusions, and one patient had both risk factors. In the four postmortem patients, the vascular pathology was similar, showing ectasia and aneurysmal dilatation confined to the large arteries of the circle of Willis. Medial fibrosis and loss of muscularis with destruction of the internal elastic lamina and intimal hyperplasia was common. The latency period following infection varied from 2 to 11 years. Once a diagnosis of aneurysmal arteriopathy was made, the patients deteriorated rapidly, with death occurring in less than 6 months. CONCLUSIONS: The development of cerebral aneurysmal arteriopathy in childhood AIDS tends to occur after a prolonged delay and is usually followed by death in a short period of time. The etiology for the vasculitis is unknown. Varicella zoster virus may be the etiology in some of the cases because of its potential to cause this pathology and the striking unilateral arterial involvement found in Case 5. HIV vasculitis is also a possibility, as suggested by the detection of HIV protein or genomic material in two of the four autopsy cases.

Acquired Immunodeficiency Syndrome↗
PubMed1998

HIV-1 strain-associated variability in infection of primary neuroglia.

Qualitative differences among strains of Human Immunodeficiency Virus type 1 (HIV-1) may influence viral infectivity for cells of the central nervous system (CNS) and determine or at least significantly influence the neuropathogenesis of brain infection. In this study, we compared infectivity for these cells in vitro among several different laboratory-adapted HIV-1 strains differing in cellular tropism. These strains included three lymphotropic strains (SF2, NL4-3, and SG3.1), two macrophage-tropic strains (SF128A, SF162), and one brain-derived strain (YU2). In microglia, macrophage-tropic strain SF128A established productive infection while the lymphotropic strain SF2 did not. In infected astrocytes, all HIV-1 strains transiently produced variable and much lower levels of p24 antigen. Viral DNA env or tat gene sequences were amplified from infected astrocytes; the amplified signals varied among HIV-1 strains, but the strongest viral DNA signals were obtained from cells infected by the lymphotropic strains SF2 and SG3.1. Transfection of astrocytes with infectious HIV-1 proviral DNA clones confirmed the observation that HIV-1 strains differ in their ability to replicate in astrocytes. Transfection revealed post-entry blocks to replication by macrophage-tropic proviruses pSF128A and pSF162. However, cytomegalovirus (CMV) superinfection of transfected astrocytes enhanced p24 production by lymphotropic HIV-1 proviruses twofold and stimulated p24 production by the otherwise inactive macrophage-tropic proviruses. This study demonstrates the spectrum of HIV-1 strain-associated variation in infectivity for neuroglia, and suggests, in addition, that herpesviral factors or viral-induced cellular factors may stimulate HIV-1 infection in astrocytes and expand the neural cell tropism of certain HIV-1 strains.

Cells, Cultured↗