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Biomedical subjects

W J Hunter

Publications and source records attributed to W J Hunter.

At least 37 records · Page 2Linked to original sources
PubMed1994

A laparoscopic intraperitoneal onlay mesh technique for the repair of an indirect inguinal hernia.

OBJECTIVE: This study was done (1) to determine whether congenital indirect inguinal hernias in male pigs could be repaired by placing a polypropylene mesh prosthesis over the defect intra-abdominally, (2) to measure the incidence of adhesions between intra-abdominal viscera and the prosthesis with and without the adhesion barrier oxidized regenerated cellulose, (3) to determine the incidence of other complications, and (4) to assess the effect on fertility. SUMMARY BACKGROUND DATA: Several techniques for laparoscopic inguinal herniorrhaphy are currently being evaluated to determine whether there are advantages over conventional inguinal herniorrhaphy. Perhaps the most controversial is the intraperitoneal onlay mesh procedure (IPOM). Its advantage is its simplicity (in that the repair is accomplished by placing a prosthesis over the hernia defect intra-abdominally, avoiding a groin dissection). Its disadvantage is the potential for complications because the prosthesis is in contact with the intra-abdominal viscera. METHODS: In male pigs, polypropylene mesh alone or polypropylene mesh plus the adhesion barrier oxidized regenerated cellulose (composite prosthesis) was fixed to the peritoneum surrounding the hernia defect. In phase 1 (6-week follow-up), two groups of 13 pigs each underwent herniorrhaphy at laparotomy or laparoscopy. In phase 2 (7.1-month follow-up), 21 pigs underwent laparoscopic herniorrhaphy. RESULTS: All IPOM herniorrhaphies were successful. The prostheses adhered most frequently to the bladder, followed by small bowel, peritoneum, and cord structures. Prosthetic erosion into these organs was not observed. Laparoscopically placed prostheses in phases 1 and 2 had significantly less surface covered by adhesions (13% +/- 13% and 19% +/- 27%, respectively) and a lower adhesion tenacity grade (1.5 +/- 0.9 and 1.3 +/- 1.1, respectively) than those placed at laparotomy (44% +/- 27% and 2.5 +/- 0.7, respectively; p < 0.01). In phase 1, a histologic evaluation of laparoscopically placed specimens demonstrated significantly thinner above-mesh fibrotic tissue compared with the prostheses implanted at laparotomy (p < 0.04). In either phase, the use of the adhesion barrier did not produce any histologic difference between the polypropylene alone and the composite prosthesis. Fertility studies were performed in phase 2 and showed no adverse effects caused by either prosthesis. CONCLUSIONS: This study demonstrated that the intraperitoneal placement of a polypropylene prosthesis was an effective technique for indirect inguinal herniorrhaphy in a pig. Furthermore, with laparotomy, the addition of oxidized regenerated cellulose significantly decreased the rate of adhesion formation to the prosthesis. However, oxidized regenerated cellulose would appear to have no value when used with a prosthesis placed laparoscopically.

Animals↗
PubMed1993

Mortality of professional chemists in England and Wales, 1965-1989.

Several studies on the mortality of chemists have revealed a lower overall mortality but an excess of deaths from certain diseases, in particular, cancers. This study determined the causes of mortality of 4,012 chemists among 14,884 members of The Royal Society of Chemistry who were followed for a period of 25 years. The results demonstrated consistency with other studies. There was an overall low mortality rate, with fewer deaths than expected from cancers, but an excess mortality from lymphatic and hematopoietic cancers, in particular leukemias. There was an excess of deaths from certain gastrointestinal cancers. There was reduced mortality from respiratory diseases, including lung cancers, and from cardiovascular disease. New findings reported in this study are increased mortality from cancers of the duodenum and kidney, certain skin cancers, mental disorders, and diseases of the nervous system.

Cause of Death↗
PubMed1993

Functional and morphological assessment of rat aorta stored in University of Wisconsin and Eurocollins solutions.

University of Wisconsin (UW) and Eurocollins (EC) solutions are widely used for preservation of organs before transplantation. However, effect of storage solutions on vascular interface for transplant success is not known. In this study, we have used rat aorta as a model and assessed the effects of cold storage in UW and EC solutions on smooth muscle and endothelial function and the morphology. Smooth muscle and endothelial functions of the rat aorta were assessed using in vitro isometric tension measurement. Morphologic studies were done with scanning and transmission electron microscopy. No significant difference in contractile response to either norepinephrine (NE) or potassium chloride was observed between control aorta and aorta stored in UW solution for 1 hr or 24 hr. In contrast, sensitivity, but not the reactivity to NE and KCl, was increased in aorta stored in EC solution for 1 hr. If the tissues were stored in EC solution for 24 hr, both sensitivity and reactivity to NE and KCl were significantly reduced. Relaxatory response to acetylcholine, in endothelium-intact vessels were reduced in aortas stored in EC solution, but not in UW solution. The magnitude of relaxations observed in tissues stored in the EC solution for 24 hr was less than in tissues stored for 1 hr. Sodium nitroprusside elicited similar relaxatory response in endothelium-denuded control tissue and in tissues stored in UW and EC solution. Electron microscopy data revealed marked swelling of the cell, loss of mitochondria and other intracellular organelles, and striking calcium deposits after preservation of the vessels in EC for 1 or 24 hr. In aorta stored in UW solution for 24 hr, endothelial and smooth muscle cells were intact, with moderate-size vacuoles in the cytoplasm. These results suggest that the UW solution is more suitable than EC solution for short-term preoperative storage of blood vessels.

Acetylcholine↗
PubMed1993

Ethylene Production by Root Nodules and Effect of Ethylene on Nodulation in Glycine max.

Nodulated soybean roots produced more ethylene and contained more 1-aminocyclopropane-1-carboxylic acid than uninoculated roots. Nodules produced more ethylene and contained more 1-aminocyclopropane-1-carboxylic acid per gram of material than roots. Almost all of the ethylene produced by the nodules was produced by the plant fractions of the nodules. Ethylene, at physiological concentrations, did not inhibit nodulation in soybeans.

Journal Article↗
PubMed1993

Imipenem-induced seizure: a case of inappropriate, excessive, and prolonged surgical prophylaxis.

Imipenem-cilastatin is a broad spectrum antibiotic that is generally used for antibiotic-resistant hospital-acquired infections. Imipenem has been reported to cause CNS toxicity including seizures in 1.5-10% of patients. The authors present a case in which imipenem, inappropriately utilized for surgical prophylaxis in excessive doses (1 gram every six hours) and for a prolonged period of time (24 days), induced a tonic-clonic generalized seizure in a patient with no history of seizure activity. The identification of this ADR lead to a number of clinical and administrative actions within our institution. Drug-induced seizures have occurred and will continue to occur as healthcare professionals exceed recommended dosing guidelines to treat critically ill patients. As pharmacists, it is extremely important to use therapeutic drug monitoring and pharmaceutical care principles to assist physicians in individualizing drug regimens for our patients to prevent these ADRs from occurring, thereby significantly effecting patients' outcomes.

Aged↗
PubMed1992

Healing of high-porosity polytetrafluoroethylene arterial grafts is influenced by the nature of the surrounding tissue.

The aim of this study was to determine the influence of the nature of the perigraft tissue in the healing pattern of high-porosity polytetrafluoroethylene (PTFE) vascular grafts. Nine-centimeter long segments of unreinforced experimental high-porosity (60 microns) PTFE grafts were placed as abdominal aortic interposition in mongrel dogs. Three grafts served as controls (group A); in five dogs (group B) a 25 x 25 cm piece of devascularized omentum was wrapped around the graft. In five dogs (group C) the omentum with its own vascular supply was completely wrapped around the graft. Animals were killed 4 weeks after surgery. The percentage of thrombus-free area was 31% in group A grafts, 39% in group B grafts, and 79% in group C grafts (p less than 0.01). Scanning electron microscopy showed many confluent areas of endothelium-like cells in the midportion of group C grafts, corresponding to capillary ingrowth. Transmural endothelial migration was more evident in group C grafts. We conclude that the nature of the perigraft tissue influences transmural capillary migration and the endothelialization rate of high-porosity PTFE grafts in dogs. Agents able to increase capillary formation in the perigraft tissue might improve endothelialization of vascular grafts.

Animals↗
PubMed1990

Comparison of two techniques to isolate microvascular endothelial cells from the omentum.

The purpose of the study was to compare two different techniques for isolation of omental microvascular endothelial cells (ECs). Segments of unreinforced polytetrafluorethylene (PTFE) grafts, 9 cm long and 6 mm in diameter, were implanted in 22 dogs as an aortic interposition. Fourteen grafts were seeded with a mean of 7 x 10(5) viable ECs, derived from the microvessels of the omentum: eight grafts (group A) were seeded with ECs obtained by collagenase digestion and by filtration through a pore mesh; six grafts (group B) were seeded with ECs obtained by collagenase digestion and by Percoll gradient separation. In eight grafts (group C), the ECs were not added to the preclot mixture and served as a control. Animals were sacrificed 5 weeks after surgery. The percentage of thrombus-free area was 65 +/- 22% for group A grafts and 74 +/- 15% for group B grafts (NS). The subendothelial layer was 280 +/- 60 microns thick in group A and 220 +/- 30 microns thick in group B (P less than 0.05). Seeded grafts showed a higher production of 6-keto-PGF1 alpha after addition of sodium arachidonate than control grafts. Percoll gradient separation allows isolation of a more purified suspension of ECs. Refinements in omental EC procurement are still required to minimize contamination with other types of cells.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Inflammatory aneurysms of the abdominal aorta: incidence, pathologic, and etiologic considerations.

Among 486 patients undergoing repair for abdominal aortic aneurysm (AAA) during a 12-year period, 30 (6.2%) had evidence of "inflammatory" AAA. One patient (3%) had acute rupture, and six patients (20%) had chronic contained rupture. Ureteral obstruction was evident in 20% of the patients. In the early period of the study there were two postoperative deaths and operative time and blood loss were significantly increased. In the last period of the study, no attempt was made to separate the duodenum and the ureters from the aneurysm; there was no operative mortality, and operative time and blood loss were similar to that of patients with atherosclerotic aneurysms. In 23 of 100 specimens of atherosclerotic AAA, microscopic findings resembling inflammatory AAA were found. On the basis of our study we conclude the following: (1) Inflammatory AAAs are simply atherosclerotic aneurysms that show an unusual accentuation of the chronic inflammation observed in relation to atherosclerotic aneurysms. (2) Operative technique should be modified to avoid excessive dissection and lysis of ureters and duodenum. (3) Excellent early and late results can be expected with proper surgical technique. (4) The causes of AAA are multiple, and chronic contained rupture of the aneurysm and reactive lymphatic hyperplasia might play a role of greater significance than previously thought.

Aged↗
PubMed1989

Natural history of recurrent carotid artery disease.

Controversy exists as to whether early and late recurrent stenosis of the carotid artery represents two distinct types of recurrence or whether it is the same type of lesion detected at different times. Eleven specimens from patients whose carotid arteries were reoperated upon were examined. A temporal sequence was noted: with increasing intervals, the relative presence of areas of myointimal hyperplasia tended to decrease, whereas the relative presence of features of atherosclerosis tended to increase. The clinical data and B-mode ultrasound studies performed from one to 190 months after 210 carotid endarterectomies were reviewed. Twenty-seven carotid arteries (12.9 per cent) exhibited hemodynamically significant restenosis. Three ultrasonographic patterns were described: homogenous soft plaque, homogenous hard plaque and heterogenous plaque. A previous correlation between ultrasonographic and pathologic findings showed the three ultrasound patterns to correlate with myointimal hyperplasia, fibrous atherosclerotic plaque and complex atherosclerotic plaque, respectively. Soft plaques were detected earlier than heterogenous plaques (p less than 0.001). Results from serial studies showed progression of soft plaque to hard or heterogenous plaque, or both. Early and late recurrent lesions are the same type of lesion detected at different intervals. Symptoms of cerebral ischemia are more common at the stage of heterogenous plaque (p = 0.02).

Aged↗
PubMed1988

Priority setting for health surveys of workers.

In determining the priorities for health surveys of workers, several factors need to be assessed, including (a) existing legislation, (b) the identification of an agent as hazardous and (c) the potential value of the surveys. Each of these factors has been examined in more detail with a view to determining the various elements that need to be taken into account in establishing priorities. In addition, a review has been made of occupational health services and of occupational health monitoring in the European Community.

Environmental Monitoring↗
PubMed1988

Seeding with endothelial cells derived from the microvessels of the omentum and from the jugular vein: a comparative study.

Segments of an experimental polytetrafluoroethylene graft (9 cm long, 6 mm I.D.) of high porosity were implanted in 25 dogs as aortic interposition grafts. Nine grafts were seeded with a mean of 7 x 10(5) viable endothelial cells (ECs) derived from the jugular vein (group A) and eight were seeded with a mean of 7 x 10(5) viable ECs derived from the microvessels of the omentum (group B). Eight grafts were not seeded and they served as controls (group C). Animals were put to death 5 weeks after graft implantation. The thrombus-free area was measured at 81% +/- 10% in group A, 65% +/- 22% in group B, and 25% +/- 13% in group C (p less than 0.05, group A vs group B; p less than 0.05, group B vs group C). The thickness of the subendothelial layer was 151 +/- 60 microns in group A, 280 +/- 60 microns in group B, and 100 +/- 75 microns in group C (p less than 0.001, group B vs groups A and C). The production of 6-keto-PGF1 alpha in the presence of sodium arachidonate was higher in seeded grafts (p less than 0.05). Omentally derived microvessel ECs can be seeded in vascular grafts; refinements in the technique of EC procurement are required to minimize contamination and to obtain ECs with more effective biologic activity.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Congenital abdominal aortic aneurysms in the young. Case report and review of the literature.

Aneurysms of the aorta are rare in children and young adults. We report a case of a 19-year-old man with a saccular abdominal aortic aneurysm (AAA). No associated disorders were discovered in this patient. The aneurysm was resected and a Dacron aortic graft was implanted. Nine years after operation the patient was in good health without evidence of other aneurysms. Thirty-two cases of probable congenital abdominal aortic aneurysms were collected from the literature. In 19 cases, the cause of aneurysm was not ascertained. We identified two groups of patients with probably congenital AAAs: type I congenital AAA, in which there is a generalized disorder of the arterial tissue and usually aneurysms are present in other areas and type II congenital AAA, in which there is a localized defect of the abdominal aorta, without aneurysms in other areas. We speculate that a congenital defect localized to the wall of the abdominal aorta was the cause of the aneurysm in this patient (type II congenital AAA).

Adult↗
PubMed1988

Ultrasonographic features of carotid plaque and the risk of subsequent neurologic deficits.

In a prospective study, 214 consecutive patients considered not to be candidates for surgical intervention were evaluated by means of duplex scanning. Of the patients, 135 had no symptoms and 79 had a history of previous neurologic symptoms. In 139 sides duplex scanning demonstrated nonhemodynamic stenosis (lumen diameter reduction, less than 50%) and in 99 sides, hemodynamic stenosis (lumen diameter reduction, 50% or greater). Of the 238 carotid artery plaques examined, 167 were homogenous and 71 were heterogenous. During a mean follow-up of 34 months, 27 new focal neurologic deficits occurred. Patients with previous symptoms had a higher incidence of new deficits (18/79 vs 9/135) (p less than 0.01). The severity of the stenosis and the presence of a heterogenous plaque were statistically correlated with the occurrence of new deficits (p less than 0.001). Multivariate analysis showed that the ultrasonographic pattern and the severity of the stenosis were independent variables. We conclude that a heterogenous plaque should be considered an unstable plaque with the possibility of causing cerebral ischemia.

Aged↗
PubMed1987

Influence of 5-Methyltryptophan-Resistant Bradyrhizobium japonicum on Soybean Root Nodule Indole-3-Acetic Acid Content.

Bradyrhizobium japonicum mutants resistant to 5-methyltryptophan were isolated. Some of these mutants were found to accumulate indole-3-acetic acid (IAA) and tryptophan in culture. In greenhouse studies, nodules from control plants inoculated with wild-type bradyrhizobia contained 0.04, 0.10, and 0.58 mug of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules, respectively. Nodules from plants inoculated with 5-methyltryptophan-resistant bradyrhizobia contained 0.94, 1.30, and 10.6 mug of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules, respectively. This manyfold increase in nodule IAA content indicates that the Bradyrhizobium inoculum can have a considerable influence on the endogenous IAA level of the nodule. Further, these data imply that much of the IAA that accumulated in the high-IAA-containing nodules was of bacterial rather than plant origin. These high-IAA-producing 5-methyltryptophan-resistant bacteria were poor symbiotic nitrogen fixers. Plants inoculated with these bacteria had a lower nodule mass and fixed less nitrogen per gram of nodule than did plants inoculated with wild-type bacteria.

Journal Article↗
PubMed1986

[Epidemiology and prevention of occupational health hazards within the European Community].

Since 1978 the European Community has had an action programme on safety and health at work covering all 120 million workers in the Community. On the basis of this programme, directives (instruments of Community legislations) have been adopted by the Council of Ministers and new directives are being drafted. The aim of these directives is to improve safety at work and to protect the health of workers from mechanical, physical, chemical and biological hazards. The drafting of proposals by the Commission for presentation to the Council necessitates detailed and critical examination of the scientific data available, such as epidemiological studies, statistical data and the results of experiments. Epidemiological studies of cases of mesothelioma have led us to propose more stringent limit values for crocidolite than for other asbestos fibres in the air at the place of work. At present, in order to gain a clearer idea of the carcinogenicity of the various compounds of nickel, efforts are being made to collate and update all the epidemiological studies conducted on this subject throughout the world. Finally, particular attention is being paid to the opportunities provided by the anti-poison centres for developing clinical toxicology and epidemiology.

Asbestosis↗
PubMed1982

Biohydrogenation of unsaturated fatty acids. Purification and properties of cis-9,trans-11-octadecadienoate reductase.

The enzyme catalyzing the second step in the biohydrogenation pathway of linoleic acid by Butyrivibrio fibrosolvens cis-9,trans-11-octadecadienoate reductase has been purified to near homogeneity. It has a molecular weight of 60,000 and appears to be a single subunit. The purified enzyme contains 2 mol of iron, 10 mol of fucose, and 12 mol of galactose per 60,000 g. The iron, but not the carbohydrate, is required for enzymatic activity. Phosphatidylethanolamine was also found to be associated with the purified enzyme. Unlike the cell extract that can reduce the double bond of the fatty acid with NADH or alpha-tocopherolquinol as a reductant, the purified enzyme can utilize only alpha-tocopherolquinol. This indicates that another component of the reduction system exists that couples the production of alpha-tocopherolquinol to the oxidation of NADH.

Amino Acids↗
PubMed1982

Studies of a human mesothelioma.

Abdominal fluid from a patient with mesothelioma was cultured in vitro, and a cell line designated JMN was established. This cell line has undergone more than 100 passages. Electron microscopic, karyotypic, and heterotransplantation studies as well as the capability of collagen synthesis by this cell line indicated that it is of malignant mesothelial origin. The cell line has proved very useful for the isolation of human pathogenic viruses.

Abdominal Neoplasms↗