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Biomedical subjects

M King

Publications and source records attributed to M King.

At least 505 records · Page 28Linked to original sources
PubMedDate not supplied

Nicotine-induced neuroepithelial cell changes in young rabbits: a preliminary communication.

Nicotine, 1 mg/kg body weight/day, was injected subcutaneously in 3 female rabbits during gestational and lactating periods, and the lungs of the offspring were studied by scanning and transmission electron microscopy (SEM and TEM) on days 5, 10, and 25 postpartum. Three other female rabbits served as controls. The size and number of neuroepithelial bodies (NEB) as estimated by SEM were larger in the experimental group than in the control group, especially on days 5 and 25. Moreover, the NEB in the nicotine-exposed groups showed loss of normal boundaries and derangement of cells and granules by TEM. Neural components also became prominent. These findings suggest that chronic maternal exposure to nicotine may directly, or, through the neural route, indirectly induce hyperplasia and dysplasia of the NEB in the offspring of rabbits. Because NEB are suspected to regulate regional bronchial and vascular smooth muscle cells, such alterations may be similar to respiratory functional impairments found in infants of mothers who smoke.

Animals↗
PubMedDate not supplied

The effect of tasuldine, a bronchosecretolytic agent, on mucus rheology and clearability and the interaction with acetylcholine in ferrets.

Tasuldine (Ts) is an orally active bronchosecretolytic agent shown to be clinically effective in human studies. Tasuldine decreases the sialomucin content of the mucus and, in animal studies, this modulation of the glycopeptide correlates with decreased mucus viscosity. The aim of this study was to evaluate the effect of tasuldine on mucus viscoelasticity and correlate the rheological changes to mucociliary and cough clearability. Tracheal mucus samples were collected from anaesthetized adult ferrets by a modification of the cytology brush technique. Mucus was collected prior to and following administration of either vehicle (normal saline) or Ts (10 mg/kg i.v.), and followed by acetylcholine (ACH) challenge (ca. 4 ml of 10(-2)M i.v., slow infusion). The analysis included magnetic microrheometry to measure the viscosity and elasticity of microlitre quantities of mucus. Mucociliary transportability (NFPTR) was measured by means of the frog palate assay and mucus collection rates (mg/min) were used as an indirect measure of secretion rate. The principal index of mucus rigidity, log G*, decreased with tasuldine infusion (P = 0.014) and further decreased with ACH (P = 0.002). In simple terms, the mucus became less rigid or more deformable with tasuldine administration, thus benefiting clearability based on predictions from model studies. The changes observed with acetylcholine alone were consistent with a classic secretagogue response--the outputting of a large volume of watery mucus. NFPTR increased with tasuldine treatment, and even further with acetylcholine; however, the combination of Ts and ACH resulted in a decrease in NFPTR close to baseline, which was likely due to the fact that the resulting mucus was too liquid for maximal mucociliary efficiency. The index of mucus flux (mg/min) was very much elevated with ACH compared with control; this was not the case with Ts. This indicates that tasuldine, despite improving the rheological properties of the mucus, did not stimulate hypersecretion, as was the case for acetylcholine. The changes in mucus rheology with infused tasuldine can be considered beneficial with respect to their effects on predicted mucociliary and cough clearability, supporting the clinical effectiveness of this type of mucolytic therapy in airway diseases such as chronic bronchitis. The study also illustrates the potential danger of overliquification of mucus.

Acetylcholine↗
PubMedDate not supplied

Computer-assisted rheological evaluation of microsamples of mucus.

Dynamic viscoelasticity measurements are required in many studies on biological fluids and they can be performed by determining the corresponding strain when a sinusoidal shear stress is applied to a sample. In several circumstances the amount of fluid that can be obtained for analysis in physiological conditions does not exceed microliters. In this context, the microrheometer technique is a useful approach to determine the dynamic rheological profile of the samples. However, the manual calculation of the desired parameters is tedious and time-consuming. This paper describes a menu-oriented program in order to facilitate its use by non-experts. The comparison between manual and computer-aided calculations demonstrated that the program reduced the time of measurement, and reduced intra- and interobserver variations. The program was developed on an IBM compatible PC in Microsoft C 5.1, and tested in a blind study to check the advantages in terms of time and reproducibility of the system verified by the concordance of two independent observers (interobserver influence) in two different occasions (intraobserver influence).

Bronchi↗
PubMedDate not supplied

Aortocaval fistula secondary to mediastinitis.

Aortocaval fistula is a rare entity usually associated with a preexistent atherosclerotic abdominal aortic aneurysm or trauma. We present a case of an aortocaval fistula secondary to the subdiaphragmatic progression of a mediastinitis. The pathogenesis, clinical presentation, and treatment are discussed.

Adult↗
PubMedDate not supplied

Low Reynolds number turbulence modeling of blood flow in arterial stenoses.

Moderate and severe arterial stenoses can produce highly disturbed flow regions with transitional and or turbulent flow characteristics. Neither laminar flow modeling nor standard two-equation models such as the kappa-epsilon turbulence ones are suitable for this kind of blood flow. In order to analyze the transitional or turbulent flow distal to an arterial stenosis, authors of this study have used the Wilcox low-Re turbulence model. Flow simulations were carried out on stenoses with 50, 75 and 86% reductions in cross-sectional area over a range of physiologically relevant Reynolds numbers. The results obtained with this low-Re turbulence model were compared with experimental measurements and with the results obtained by the standard kappa-epsilon model in terms of velocity profile, vortex length, wall shear stress, wall static pressure, and turbulence intensity. The comparisons show that results predicted by the low-Re model are in good agreement with the experimental measurements. This model accurately predicts the critical Reynolds number at which blood flow becomes transitional or turbulent distal an arterial stenosis. Most interestingly, over the Re range of laminar flow, the vortex length calculated with the low-Re model also closely matches the vortex length predicted by laminar flow modeling. In conclusion, the study strongly suggests that the proposed model is suitable for blood flow studies in certain areas of the arterial tree where both laminar and transitional/turbulent flows coexist.

Arteries↗
PubMedDate not supplied

Test-retest reliability of a procedure for measuring extensibility of the extrinsic finger flexor muscles.

This study assessed the test-retest reliability of a procedure designed to provide torque-controlled measurements of the extensibility of extrinsic finger flexor muscles. The extensibility of the extrinsic finger flexor muscles of both hands of nine patients who had spinal cord injuries was measured on two consecutive days. On each day a total of three measurements were obtained for each hand. Intraclass correlation coefficients (ICCs) and percent close agreement scores were used to assess agreement between the mean measurements obtained on day 1 and those obtained on day 2. An ICC of 0.85 was obtained. Measurements obtained on day 1 were within 5 degrees of the measurements obtained on day 2 83% of the time. The procedure is therefore sufficiently reliable for many clinical and research applications.

Adult↗
PubMedDate not supplied

The benefits of fluoropassivation of polyester arterial prostheses as observed in a canine model.

The effect of treating the surface of a polyester vascular prosthesis with a novel fluoropolymer before sealing the graft with gelatin has been evaluated in a canine thoracoabdominal bypass model. The healing behavior of the Fluoropassiv graft was compared with that of the Gelsoft ERS prosthesis used as control for prescheduled periods of implantation ranging from 4 hr to 6 months. Both series of explanted grafts were analyzed using macroscopic, histologic, and scanning electron microscopic observations, and by determining the prostacyclin/thromboxane A2 ratio (PGI2/TXA2) and the thrombogenicity of the luminal surface by means of labelled platelets and fibrin deposition. Chemical analysis of explanted and cleaned graft segments was performed using electron spectroscopy for chemical analysis, differential scanning calorimetry, and contact angle methods. No difference in platelet and fibrin deposition or PGI2/TXA2 secretion by the luminal surface was observed between the treated and the control grafts at any implantation period. On the other hand, pathologic investigation has revealed that, although there is no difference between the two grafts during the first month, the healing sequence of the Fluoropassiv graft appeared more complete and mature than the control graft after 3 and 6 months. Differences were observed in the extent of collagenous internal capsular development, endothelialization, and tissue penetration into the knitted structure. The presence of fluorine and a higher contact angle at the surface of all the explanted fluoropassivated grafts is believed to have been responsible for reducing the inflammatory response and enhancing the long-term healing behavior of this novel prototype device over the control gelatin sealed prosthesis.

Animals↗
PubMedDate not supplied

Polyester arterial prostheses. Recent developments from the Czech Republic and Poland.

To evaluate recent developments in the design and production of polyester vascular prostheses in eastern Europe, a series of in vitro physical and chemical tests and an in vivo study was performed on three new prototype devices from the Czech Republic and one from Poland. The in vitro results for these four prostheses, referred to as the Ra-1n (warp knitted, uncrimped), Ra-1v (warp knitted, crimped), Mikrofroté (weft knitted, uncrimped), and Dallon (warp knitted, crimped) prostheses, were compared against values for three commercial devices of western origin, namely the Triaxial, the Vasculour II, and the Cooley II grafts. The animal trial involved implanting the four prototype devices as a thoracoabdominal bypass in dogs for eight different periods ranging from 4 hrs to 6 months and undertaking histologic and structural investigations on the retrieved grafts. Because of its poor long-term dimensional stability in vivo, the continued use of a weft knitted structure, like the Mikrofroté prosthesis, is to be deprecated. Conversely, the introduction of a more dimensionally stable warp knitted structure in three prototypes is to be acknowledged. However, the presence of surface contaminants was most likely responsible for the excessive inflammatory reaction generated by all four prostheses during the first month in vivo, which resulted in delayed healing performance. In addition, an unusually high surface carbon-oxygen ratio suggests that the crimping process needs further refinement. Improved cleaning and packaging procedures are essential before these products can complete against existing commercial prostheses of western origin. In conclusion, these new developments illustrate that the technology of warp knitting, which is now spreading worldwide, should be evaluated.

Animals↗
PubMedDate not supplied

Routine computerized tomography scanning, groin ultrasound with or without fine needle aspiration cytology in the surgical management of primary squamous cell carcinoma of the vulva.

We set out to study whether computerized tomography (CT) scanning of the vulva and the groin and groin ultrasound scanning (USS) alone or with fine needle aspiration cytology (FNAC) (USS/FNAC) influenced or could influence the surgical management of primary squamous cell carcinoma of the vulva (SCCaV). Forty-four patients underwent surgery for primary SCCaV following radiologic imaging by one or more modalities. Patient details included the clinical assessment of the carcinoma, radiologic findings, the operation performed, and whether the decision regarding the type and extent of surgery for the vulval carcinoma and, in particular, for the groin node dissection was or could be influenced by the radiologic findings. The age range was 38-87 years, with a median of 74 years. A total of 75 groin dissections were performed. Twenty-five of the 44 patients (56.8%) did not have groin node metastasis, 14 had unilateral metastasis (31.8%), and 5 (11.4%) had bilateral metastasis. All cases with histologically proven nodal status were analyzed to compare the preoperative imaging status with the histology. The calculated sensitivity, specificity, negative predictive value, and positive predictive value for CT were 58%, 75%, 75%, and 58%, for USS alone-87%, 69%, 94%, and 48%, and for USS-guided FNAC-80%, 100%, 93%, and 100%, respectively. There was no patient in whom surgical planning for the vulval carcinoma or the groin nodes was or could be altered by the CT findings. The data do not support the routine use of CT scanning in patients with primary SCCaV, either in assessment of the primary vulval carcinoma or in detecting groin nodal metastases. For the groin nodes, USS/FNAC is superior to CT in assessing disease status. In contrast to CT, USS/FNAC may have a useful clinical role in the management of the groin nodes in vulval carcinoma.

Adult↗
PubMedDate not supplied

Bronchial mucus properties in lung cancer: relationship with site of lesion.

OBJECTIVE: To compare the biophysical properties of mucus from the left and right mainstem bronchi in patients undergoing diagnostic bronchoscopy because of a unilateral radiological abnormality. It was hypothesized that abnormalities in the properties of mucus would be greater on the side with the lesion and that this would be most obvious in patients with unilateral lung cancer. PATIENTS AND METHODS: Bilateral paired samples of bronchial mucus were taken from 38 nonatopic patients (aged 59.8+/-12.6 years) including 16 nonsmokers, 14 current smokers and eight exsmokers (more than one year). Twenty of the 38 patients had a radiologically defined unilateral abnormality. Eight of these 20, including one nonsmoker, had lung cancer. The viscoelastic properties of the collected mucus were determined by magnetic microrheometry, and the analysis was carried out without knowledge of the histological diagnosis or source. RESULTS: The rheological properties of mucus strongly suggested which was the abnormal side. Within the group of 20 patients with a unilateral radiological abnormality, mucus from the side of the lesion had a lower value of the loss tangent, tan d100 (P=0.004), indicating greater mucus recoil. This is consistent with poor mucus cough clearability on the lesion side. All eight cancer patients fit this mucus rheological pattern with a lower value of tan d100 on the affected side (P=0.007). Four of the five other patients with a similar mucus abnormality were categorized as high cancer risk by other criteria, while six of seven patients with mucus that did not have this abnormality were considered to be lower risk. Based on the mucus analysis done at the time of the bronchoscopy, two of the 'noncancer' patients initially designated as high risk had cancer detected after several months of follow- up. Only two of the 18 patients without a defined unilateral lesion fit the mucus 'cancer pattern'. CONCLUSIONS: These findings are consistent with the hypothesis that either abnormalities in mucus properties may represent a risk factor for the development of lung cancer or that bronchial mucus abnormalities may be associated with products secreted by the tumours that, in turn, may suppress mucus clearance.

Adult↗
PubMedDate not supplied

Treatment of heterotopic cervical and intrauterine pregnancy.

OBJECTIVE: To find a suitable technique to selectively terminate a cervically implanted embryo while maintaining viability of a concomitant intrauterine pregnancy. METHODS: A 34-year-old patient achieved a twin pregnancy after 4 IVF attempts. Ultrasound revealed a viable intrauterine and cervical pregnancy. Given our experience with KCl injection for fetal reduction, we offered the patient an attempt to reduce the cervical pregnancy. RESULTS: Best visualization in this case was obtained by transabdominal scanning. A 6-inch 20-gauge spinal needle was inserted transcervically and maneuvered into the thorax of the embryo. Fetal heart rate ceased even before KCl could be injected. Then 3 cm(3) of saline were injected to provide better visualization of the cervical fetus, and to confirm absence of heart beat. The patient had minor vaginal bleeding for several days. The intrauterine pregnancy progressed uneventfully through 36(1)/(2) weeks with delivery of a healthy, 2, 700-gram newborn. CONCLUSION: Cervical pregnancy is usually considered a life-threatening event. Other factors such as concomitant intrauterine pregnancy and the patient's infertility history generally would be secondary concerns. In this case, we were able to selectively terminate the cervical pregnancy, while preserving the intrauterine one, allowing this couple to have a healthy newborn. Further cases will be necessary to appropriately define risk rates for such an approach.

Abortion, Therapeutic↗
PubMedDate not supplied

In utero fetal muscle biopsy alters diagnosis and carrier risks in Duchenne and Becker muscular dystrophy.

OBJECTIVES: We have previously shown that Duchenne muscular dystrophy (DMD) can be diagnosed by fetal muscle biopsy and immunohistochemical staining showing the absence of dystrophin. In Becker muscular dystrophy (BMD), there is a variable dystrophin staining pattern. STUDY DESIGN: A 26-year-old, gravida 5, para 1, SAB 2, VIP 1, white female had a son with the diagnosis of BMD, with no other affected family members. In the current pregnancy, the male fetus inherited the same X chromosome. RESULTS: Fetal muscle biopsy revealed no dystrophin, consistent with the diagnosis of DMD, prompting re-analysis of the sibling whose diagnosis was then changed to DMD. CONCLUSIONS: Molecular techniques in prenatal diagnosis in this case not only led to the diagnosis of a severe disorder in the current pregnancy, but changed the diagnosis in another child, allowing for more appropriate counseling of this couple.

Abortion, Induced↗