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Biomedical subjects

D Martin

Publications and source records attributed to D Martin.

At least 289 records · Page 16Linked to original sources
PubMed1998

Experimental bladder instability following bladder outlet obstruction in the female rat.

PURPOSE: In rats, urethral obstruction was previously shown to lead to detrusor instability, but bladder instability in conscious animals has not been well characterized. The present study was designed to describe the consequences of bladder outlet obstruction on urodynamic parameters in the conscious rat. A categorization of different types of bladder instability in conscious rats is described. MATERIALS AND METHODS: Cystometry was performed on conscious animals with chronically implanted lines. Recordings of the micturition pattern and the bladder pressure during the micturition cycle were made from normal female rats and those with instability caused by infravesical outflow obstruction. RESULTS: In control rats, the peak micturition pressure was low (45.6+/-2.5 cm. H2O) and only small pressure fluctuations occurred before or after micturition. Rats with outlet obstruction exhibited bladder hypertrophy, high micturition pressure (95.5+/-6.8 cm. H2O) as well as marked spontaneous activity throughout the micturition cycle. According to the spontaneous activity profile we identified four main patterns of abnormal micturition cycles. CONCLUSION: Urethral obstruction in rats leads to a significant increase in bladder weight and to altered micturition patterns which reveal clear similarities with features of the cystometric profiles performed in men with infravesical outflow obstruction. These modifications are not consistently correlated with an increase in bladder weight.

Animals↗
PubMed1998

Growth of preterm infants with cystic periventricular leukomalacia.

Etiology of the high rates of growth failure in children with cerebral palsy (CP) remains unclear. The purpose of this study was to evaluate the relation between growth failure in preterm infants with cystic periventricular leukomalacia (CPVL) and neonatal health complications. The population consisted of all preterm infants (51) with a gestational age of <33 weeks who were admitted to the Children's Hospital of Buffalo from 1988 to 1993 and who had CPVL. Out of the 41 survivors with CPVL who were followed, 39 developed CP and 18 developed growth failure during infancy. At the time of greatest growth failure, the majority (72%) of infants had signs of undernutrition as defined by the Waterlow (1972) classification. Oral feeding impairment was the sole risk factor for the occurrence of growth failure. Undernutrition appears to be important in the occurrence of growth failure in preterm infants with CPVL and CP.

Anthropometry↗
PubMed1998

Fatal shoulder dystocia: a review of 56 cases reported to the Confidential Enquiry into Stillbirths and Deaths in Infancy.

OBJECTIVE: To use information collected by the Confidential Enquiry into Stillbirths and Deaths in Infancy to help obstetric, midwifery and paediatric practice in the management of shoulder dystocia. DESIGN: Review of casenotes by a multidisciplinary focus group. SAMPLE: All 56 cases reported to the Confidential Enquiry into Stillbirths and Deaths in Infancy from England, Wales and Northern Ireland in 1994 and 1995, where stillbirth or neonatal death was attributed to shoulder dystocia. MAIN OUTCOME MEASURES: Case notes were reviewed with respect to a range of perinatal variables. Comparisons were made with normative data from other studies when appropriate. RESULTS: Maternal obesity and big babies were over-represented in pregnancies complicated by fatal shoulder dystocia. Fetal compromise was recorded in 26% of labours. The median time interval between delivery of the head and the rest of the body was only five minutes. The lead professional at the time the head was delivered was a midwife in 65% of cases. Middle grade or senior obstetric staff were supervising 47% of cases by the time the body was delivered. CONCLUSIONS: Antenatal prediction of shoulder dystocia is imprecise, and the majority of deliveries are attended by midwives. A relatively brief delay in delivery of the shoulders may be associated with a fatal outcome.

Autopsy↗
PubMed1998

The validity of continuous automated fluid monitoring during endometrial surgery: luxury or necessity?

Thirty-four consecutive women undergoing endometrial laser ablation, as a treatment of menorrhagia, were recruited to assess the validity of fluid absorption monitoring by a new continuous automated system (AquaSens). The same group of women also had monitoring of fluid absorption carried out by our standard technique of weighing. The intra-class correlation coefficient for the fluid deficit estimated by AquaSens compared to our standard technique of manually weighing the irrigation bags was 0.98 (95% CI 0.96-0.99). Aquasens therefore provides a valid and non-invasive method of continuously monitoring fluid deficit amongst patients undergoing operative hysteroscopy procedures, thereby reducing the risk of unexpected fluid absorption and its potentially fatal sequelae.

Decision Making↗
PubMed1998

Ability of activation recovery intervals to assess action potential duration during acute no-flow ischemia in the in situ porcine heart. Experimental Cardiology Group, University of North Carolina at Chapel Hill.

INTRODUCTION: The ability to assess transmural changes in action potential duration during acute no-flow ischemia is essential to an understanding of the tachyarrhythmias that occur in this setting. The purpose of this study was to determine if activation recovery intervals determined from unipolar electrograms would provide this information. METHODS AND RESULTS: We recorded simultaneously transmembrane action potentials and unipolar electrograms from sites located as closely together as possible in the center and at the lateral margin of the ischemic zone during acute no-flow ischemia and correlated the changes in activation recovery intervals obtained from the unipolar electrograms to the changes in action potential duration. We found that the activation recovery intervals provided an accurate measure of the changes in action potential duration during acute no-flow ischemia provided the electrograms had a well-defined, single negative component to the QRS complex with a maximum negative dV/dt > 10 V/sec and a single positive component to the T wave having a maximum positive dV/dt > 1.6 V/sec. Electrograms meeting these criteria comprised 90% of the electrograms recorded at the margin of the ischemic zone throughout 60 minutes of no-flow ischemia. In the center of the ischemic zone, 75% of the recorded electrograms met these criteria for the first 20 minutes of no-flow ischemia. Thereafter, the percentage declined and after 40 minutes of no-flow ischemia, none of the electrograms recorded in the center of the ischemic zone met these criteria. CONCLUSION: Activation recovery intervals obtained from unipolar electrograms provide an accurate assessment of changes in action potential duration throughout the ischemic zone during acute no-flow ischemia, provided the characteristics of the electrograms meet specific predetermined criteria.

Action Potentials↗
PubMed1998

Carotid endarterectomy among Medicare beneficiaries: a statewide evaluation of appropriateness and outcome.

BACKGROUND AND PURPOSE: We sought to examine the appropriateness and the surgical outcomes of carotid endarterectomy (CE) in unselected community hospitals to identify opportunities for improvement. METHODS: We performed a retrospective review of all CEs performed on Medicare beneficiaries in Georgia in 1993 (n = 1945). Conclusions regarding appropriateness were based on current guidelines as interpreted by a physician reviewer and were supported by the aggregate results of structured, blinded overreading by clinicians with relevant expertise. Adverse outcomes were confirmed and rated as to severity by a physician. Outcomes were correlated with demography, vascular anatomic findings, comorbidity, surgical techniques, and hospital characteristics. RESULTS: The majority of the patients (51%) were asymptomatic at presentation. CEs were performed appropriately in 96.1% of the cases in accordance with current guidelines. There was no significant difference in the rate of appropriateness between the symptomatic (96%) and the asymptomatic patients (96.4%). Survival without stroke or myocardial infarction (MI) was 94.3%. The 30-day mortality was 1.9%; moderate to severe strokes occurred in 1.8%, stroke-related death in 0.7%, MI in 1.1%, and MI-related death in 0.5%. Those hospitals performing <10 CEs in the observed year had a statistically significant higher morbidity and mortality as well as an increase in less severe complications such as hematomas, wound dehiscence, wound infection, and pneumonia than did hospitals with higher volume of CEs.. Older patients and women had statistically significantly higher morbidity and mortality. Patients with a Charlson Severity Index score of > or =1 had a risk for adverse outcomes 3.4 times higher than patients with a score of 0 after adjustment for age and sex. CONCLUSIONS: The great majority of CEs performed in Georgia on Medicare patients were appropriate, according to current guidelines. Slightly more than half of the patients were asymptomatic as defined in the Asymptomatic Carotid Atherosclerosis Study. In hospitals performing <CEs in the index year, we noted higher morbidity and mortality, as well as an increase in less severe complications. This relationship between the volume of surgery and outcome was confirmed in the analysis of the 30-day mortality for all Medicare cases (n = 10,569) performed in Georgia from 1991 to 1995. This was the most important opportunity for improvement identified in this study. In view of the increased use of CE, it is important to continue to monitor the patterns of practice for this procedure to improve outcomes.

Age Factors↗
PubMed1998

Chicken (Gallus domesticus) inner ear afferents.

Neurons from the vestibular (VG) and the statoacoustic (SAG) ganglion of the chick (Gallus domesticus) were evaluated histologically and morphometrically. Embryos at stages 34 (E8 days), 39 (E13 days) and 44 (E18 days) were sacrificed and temporal bones microdissected. Specimens were embedded in JB-4 methacrylate plastic, and stained with a mixture of 0.2% toluidine blue (TB) and 0.1% basic Fuschin in 25% ethanol or with a mixture of 2% TB and 1% paraphenylenediamine (PDA) for axon and myelin measurement study. Images of the VIIIth nerve were produced by a V150 (R) color imaging system and the contour of 200-300 neuronal bodies (perikarya) was traced directly on a video screen with a mouse in real time. The cross-sectional area of VG perikarya was 67.29 micrometers2 at stage 34 (E8), 128.46 micrometers2 at stage 39 (E13) and 275.85 micrometers2 at stage 44 (E18). The cross-sectional area of SAG perikarya was 62.44 micrometers2 at stage 34 (E8), 102.05 micrometers2 at stage 39 (E13) and 165.02 micrometers2 at stage 44 (E18). A significant cross-sectional area increase of the VG perikarya between stage 39 (E13) and stage 44 (E18) was determined. We randomly measured the cross-sectional area of myelin and axoplasm of hatchling afferent nerves, and found a correspondence between axoplasmic and myelin cross-sectional area in the utricular, saccular and semicircular canal nerve branches of the nerve. The results suggest that the period between stage 34 (E8) and 39 (E13) is a critical period for afferent neuronal development. Physiological and behavioral vestibular properties of developing and maturing hatchlings may change accordingly. The results compliment previous work by other investigators and provide valuable anatomical measures useful to correlate physiological data obtained from stimulation of the whole nerve or its parts.

Animals↗
PubMed1998

Anorectic effects of the cytokine, ciliary neurotropic factor, are mediated by hypothalamic neuropeptide Y: comparison with leptin.

Although ciliary neurotropic factor (CNTF) is a tropic factor in nervous system development and maintenance, peripheral administration of this cytokine also causes severe anorexia and weight loss. The neural mechanism(s) mediating the loss of appetite is not known. As hypothalamic neuropeptide Y (NPY) is a potent orexigenic signal, we tested the hypothesis that CNTF may adversely affect NPYergic signaling in the hypothalamus. Intraperitoneal administration of CNTF (250 microg/kg) daily for 4 days significantly suppressed 24-h food intake in a time-dependent manner and decreased body weight. The loss in body weight was similar to that which occurred in pair-fed (PF) rats. As expected, hypothalamic NPY gene expression, determined by measurement of steady state prepro-NPY messenger RNA by ribonuclease protection assay, significantly increased in PF rats in response to energy imbalance. However, despite a similar loss in body weight, there was no increase in NPY gene expression in CNTF-treated rats. Daily administration of CNTF intracerebroventricularly (0.5 or 5.0 microg/rat) also produced anorexia and body weight loss. In this experiment, negative energy balance produced by both PF and food deprivation augmented hypothalamic NPY gene expression. However, despite reduced intake and loss of body weight, no similar increment in hypothalamic NPY gene expression was observed in CNTF-treated rats. In fact, in rats treated with higher doses of CNTF (5.0 microg/rat), NPY gene expression was reduced below the levels seen in control, freely fed rats. Furthermore, CNTF treatment also markedly decreased NPY-induced feeding. These results suggested that anorexia in CNTF-treated rats may be due to a deficit in NPY supply and possibly in the release and suppression of NPY-induced feeding. The possibility that CNTF-induced anorexia may be caused by increased leptin was next examined. Daily intracerebroventricular injections of leptin (7 microg/rat) decreased food intake, body weight, and hypothalamic NPY gene expression in a manner similar to that seen after CNTF treatment. Leptin administration also suppressed NPY-induced feeding. However, peripheral and central CNTF injections markedly decreased leptin messenger RNA in lipocytes, indicating a deficiency of leptin in these rats; thus, leptin was unlikely to be involved in appetite suppression. Thus, these results show that a two-pronged central action of CNTF, causing diminution in both NPY availability and the NPY-induced feeding response, may underlie the severe anorexia. Further, unlike other members of the cytokine family, suppression of NPYergic signaling in the hypothalamus by CNTF does not involve up-regulation of leptin, but may involve a direct action on hypothalamic NPY neurons or on neural circuits that regulate NPY signaling in the hypothalamus.

Adipocytes↗
PubMed1998

Validation of a self-report measure of somatic health.

The primary purpose was to assess the validity of a new self-report inventory of general somatic health status. In addition, we sought to examine the influence of social desirability and negative affectivity on health reports and to learn whether asking respondents to report concrete, memorable aspects of illness episodes such as seeing a doctor or staying home in bed for all or most of a day would enhance validity. The somatic component of the Cornell Medical Index was used as a criterion measure of health status because that Index has been shown to reflect medical records with great accuracy. Scores on the new health inventory correlated highly with the Cornell somatic scores, and this relationship was independent of negative affectivity and social desirability. The addition of the "concrete, memorable" aspects of illness accounted for no additional variance in the Cornell Index somatic scores beyond that accounted for by mere reporting of the presence of the symptom or illness. This study offers evidence supporting the validity of the Inventory of Health Status as a predictor of somatic health independent of social desirability and negative affectivity and also indicates that a simple indication of whether the patient had the symptoms is sufficient.

Adult↗
PubMed1998

Japanese encephalitis among hospitalized pediatric and adult patients with acute encephalitis syndrome in Hanoi, Vietnam 1995.

The etiologic spectrum of acute encephalitis syndrome (AES) has not been well defined in Vietnam. Cohort and case-control studies were performed on all adult and pediatric AES patients admitted to the Neurology Service of Bach Mai Hospital between June 5 and August 3, 1995. Among pediatric AES patients, 31 (67%) of 46 had acute Japanese encephalitis (JE), compared with only two (6%) of 33 adult AES patients (P < 0.0001). For confirmed JE cases, serum specimens obtained 15-21 days after symptom onset had the highest mean anti-JE IgM signal-to-noise (P/N) ratios (8.08 + 1.09 SE). A serosurvey of adult household members did not reveal any cases of recent subclinical JE infection, although 26% had evidence of past JE infection. The use of bed netting was nearly universal but did not appear to reduce the risk of AES or JE. Given the high incidence of JE, particularly among children, Vietnam seems well suited for the development of a targeted JE vaccination strategy.

Acute Disease↗
PubMed1998

Unmixing aggregate data: estimating the social composition of enumeration districts.

"In this paper the authors address the problem of interpreting and classifying aggregate data sources and draw parallels between tasks commonly encountered in image processing and census analysis. Both of these fields already have a range of standard classification tools which are applied in such situations, but these are hindered by the aggregate nature of the input data. An approach to ¿unmixing' aggregate data, and thus revealing the nature of the subunit variation masked by aggregation, is introduced. This approach has already shown considerable success in Earth Observation applications, and in this paper the authors present the adaptation and application of the approach to Census small area statistics data for Southampton, Hants, [in England] revealing something of the social composition of Southampton's enumeration districts. The unmixing technique utilises an artificial neural network."

Censuses↗
PubMed1998

False negativity by an anti-HIV assay kit (IMx 8B32) and evaluation of its replacement (IMx 8C98).

False negativity in a commercial anti-HIV kit (IMx HIV-1/HIV-2 3rd Generation Plus (code 8B32) was investigated, and the kit that superseded it (IMx HIV-1/HIV-2 III Plus, code 8C98) was evaluated. In a comparison on 574 freshly collected anti-HIV-1-positive specimens, 97.2% were more reactive in 8C98 than in 8B32; 35.5% were more than twice as reactive and 8.5% were more than four times as reactive. In 8B32, the signal from 55 specimens selected because of weak reactivity was enhanced 1.5 to 8.8 times by preliminary heating at 56 degrees C for 30 min. The reactivity of the 55 heated sera was then similar to that of the same specimens tested without heat treatment in the 8C98 assay. Reactivity in 8B32 was also increased in 66 of 76 (at least twofold in 20) randomly chosen anti-HIV-positive serum specimens by the addition of EDTA (10 mM final concentration). One of these specimens was false negative (signal:cutoff (S:CO) ratio 0.76) in 8B32, though its reactivity was restored by addition of EDTA (S:CO ratio 9.54). These findings indicate that the inhibitory effect that originally led to false negative findings in 8B32 was probably due to complement activity, and that the same activity was present in the freshly collected specimens used here to evaluate the replacement IMx anti-HIV assay (8C98). The specimen panel employed to evaluate 8C98 included 1,892 anti-HIV-positive and 779 anti-HIV-negative specimens. There were no false negative reactions. The lowest S:CO ratio observed was 6.2 and only 17 (0.2%) anti-HIV-positive specimens gave ratios less than 10. Nine unreproducible false positive reactions arose, all possibly attributable to specimen carryover by the IMx instrument. The performance of 8C98 was also compared with that of 10 other current anti-HIV kits using 21 sets of seroconversion specimens (127 specimens in total), and five performance assessment panels (92 specimens in total) comprised mostly of single bleeds from recent seroconverters. IMx 8C98 was the second most sensitive assay. We found no evidence that the 8C98 kit was prone to the effect that had given rise to false negative results in its predecessor (8B32).

AIDS Serodiagnosis↗
PubMed1998

[Role of emergency reconstruction of fingers by the "reposition-flap" technique. Report of eight cases].

Following replantation failure, fingertip reconstruction was performed as an emergency "reposition-flap" procedure in seven patients (eight fingers). This technique was intended for amputations distal to the DIP joint in long fingers, and IP joint in the thumb. Pulp was excised on the amputated segment, and the remaining bone and nail bed were reattached to the proximal stump with Kirschner wires. Pulp was reconstructed with a local advancement and sensitive flap. Trophicity and nail regrowth as well as mobility and strength were satisfactory in five cases. MRI examination showed revascularization of the distal bone fragment in four cases. This procedure is an alternative to amputation after replantation failure when patients do not accept finger shortening. The more distal the amputation, the better is the result.

Adult↗
PubMed1998

[Abdominoplasty with dissociated intraparietal liposuction. Technical note].

Liposuction has greatly contributed to the improvement of the aesthetic result of abdominoplasties. However, one should consider the high rate of seroma when liposuction is performed via an inferior approach during abdominoplasty. The authors present a new approach to achieve complete liposuction of the abdominal wall during conventional abdominoplasty. This approach is carried out via submammary incision after previous undermining of the abdominal wall. A permanent assessment of the thickness of the wall allows the liposuction to stay strictly in fat tissue. Finally, there is a total independence between liposuction and the undermining procedure which allows minimization of the postoperative seroma. This technic seems particularly useful in a context of extensive abdominal adipose with flaccidity of the abdominal wall, requiring extensive undermining. Thanks to this procedure, the authors have performed a one-stage operation in many cases in which two operations would necessary previously have been.

Abdominal Muscles↗
PubMed1998

2001 Census output areas: from concept to prototype.

This article describes the development of a prototype output area production system for the 2001 Census. A number of outstanding design issues concerning 2001 output areas are explained, and the implications of using a geographical information system for the management of census geography are explored.

Censuses↗
PubMed1998

[Facial epitheliomas: general considerations, surgical techniques and indications].

Carcinoma of the face is the skin disease most frequently encountered by plastic surgeons in everyday practice. Although basal cell carcinomas and squamous cell carcinomas are generally easy to recognize, their treatment remains subject to various schools of thought, or even individual practices, which are often difficult to define. This article defines a general plan of management of these tumours; their histological duality corresponds to a therapeutic duality. Resection of a basal cell carcinoma requires safety margins of 3 to 4 mm, versus at least 5 mm for a squamous cell carcinoma. In a high-risk subject, with a sclerodermiform carcinoma or undifferentiated squamous cell carcinoma, this safety margin may be as much as 10 mm or more. Frozen section examination is preferable in these situations. Six anatomical regions are studied selectively to define the main rules of reconstruction: nasal region, orbitopalpebral region, labial region, malar region, frontal region and auricular region. Each region will be subdivided into several subterritories, each requiring different strategies. The objectives, methods and indications of each reconstruction are selectively defined. The final strategy proposed is based not only on the author's personal experience, but also on the results of the national survey on carcinomas. As a complement to these therapeutic guidelines, the authors raise the problem of incomplete resection, which requires the definition of a peripheral infiltration index predictive of the recurrence rate. Surgery obviously cannot constitute exclusive treatment carcinomas, hence the value of presenting other methods currently available in the therapeutic armamentarium. Surveillance is essential in every case, determined by the patient's risk of recurrence or even metastatic dissemination.

Basal Cell Carcinoma↗