Biomedical subjects
Publications and source records attributed to E Browne.
We have performed searches for the electron-capture decay branches of 176Lu to the ground state and first excited state of 176Yb. No evidence of either decay mode was observed. From these measurements we have established upper limits on both of these possible branches that are each > 20 times more stringent than the single previously published limit.
This paper estimates the total cost to women and their families associated with a spontaneous vaginal delivery and five types of 'near-miss' obstetric complication in Benin and Ghana, and assesses affordability in relation to household cash expenditure. A retrospective evaluation of costs was carried out among 121 mothers in three hospitals in Ghana. A prospective evaluation of costs was undertaken among 420 pregnant women in two hospitals in Benin. Information was collected on the cost of travel to the facilities and of direct medical and non-medical costs incurred during their stay in hospital. In Benin, costs ranged from an average of 15 US dollars for a spontaneous delivery to 256 US dollars for a near-miss complication caused by dystocia. In Ghana, average costs ranged from 18 US dollars for a spontaneous vaginal delivery to 115 US dollars for a near-miss complication caused by haemorrhage. Medical costs accounted for the largest share of total costs, mainly drugs and medical supplies in Ghana and costs of the delivery and any surgical intervention in Benin. Payments associated with a spontaneous vaginal delivery amounted to at least 2% of annual household cash expenditure in both countries. In the case of severe obstetric complications, costs incurred reached a high of 34% of annual household cash expenditure in Benin. The economic burden of hospital-based delivery care in Ghana and Benin is likely to deter or delay women's use of health services. Should a woman develop severe obstetric complications while in labour, the relatively high costs of hospital care could have a potentially catastrophic impact on the household budget.
Studying 12 selected individuals from a malaria-endemic area in West Africa, 24 variants of the CD36 gene were found, 21 of them novel ones. These included three single-nucleotide substitutions causing non-conservative amino acid exchanges E123K, T174A, and I271T as well as a three base pair (bp) insertion resulting in the addition of an asparagine residue (N232-233ins). The E123K variant was located within the putative ligand-binding domain for oxidized low density lipoprotein, while the other substitutions resided outside any of the binding sites for reaction partners mapped on CD36 so far. Twelve single-nucleotide polymorphisms (SNPs) were identified in untranslated parts of the exons and in introns. Five additional SNPs were located in the promoter region whereby -144G-->T, -53G-->T, and -2A-->G alter putative binding sites for the transcription factors purine factor (PuF), phorbol ester-responsive element AP-2, and CCAAT/enhancer-binding protein. A G-->T exchange at position -50 appears to introduce a new recognition site for PuF. Calculations of nucleotide diversity revealed extraordinarily high numbers for all parts of the gene, which may, however, to some extent be due to the selection of individuals studied.
Smoking results in impaired wound healing and poor surgical results. In this retrospective study, we compared outcomes in 155 smokers, 76 ex-smokers, and 517 nonsmokers who received postmastectomy breast reconstructions during a 10-year period. Ex-smokers were defined as those who had quit smoking at least 3 weeks before surgery. Transverse rectus abdominis musculocutaneous (TRAM) flap surgery was performed significantly less often in smokers (24.5 percent) than in ex-smokers (30.3 percent) or nonsmokers (39.1 percent) (p < 0.001). Tissue expansion followed by implant was performed in 112 smokers (72.3 percent), 50 (65.8 percent) ex-smokers, and 304 nonsmokers (58.8 percent) (p = 0.002). The overall complication rate in smokers was 39.4 percent, compared with 25 percent in ex-smokers and 25.9 percent in nonsmokers, which is statistically significant (p = 0.002). Mastectomy flap necrosis developed in 12 smokers (7.7 percent), 2 ex-smokers (2.6 percent), and 8 nonsmokers (1.5 percent) (p < 0.001). Among patients receiving TR4AM flaps, fat necrosis developed in 10 smokers (26.3 percent), 2 ex-smokers (8.7 percent), and 17 nonsmokers (8.4 percent). Abdominal wall necrosis was more common in smokers (7.9 percent) than in ex-smokers (4.3 percent) or nonsmokers (1.0 percent). In this large series, tissue expansion was performed more often in smokers than was autogenous reconstruction. Complications were significantly more frequent in smokers. Mastectomy flap necrosis was significantly more frequent in smokers, regardless of the type of reconstruction. Breast reconstruction should be done with caution in smokers. Ex-smokers had complication rates similar to those of nonsmokers. Smokers undergoing reconstruction should be strongly urged to stop smoking at least 3 weeks before their surgery.
Vascular endothelial growth factor (VEGF), a potent endothelial mitogen, is secreted in ischemic tissue and plays a pivotal role in angiogenesis. We studied whether VEGF administered to a rat muscle flap at the time of ischemia induction would increase microcirculatory flow to the flap. The cremaster muscle flap was isolated on its neurovascular pedicle. Ischemia was induced by clamping the vascular pedicle, and 0.2 ml of either VEGF (0.1 microg) or vehicle (phosphate-buffered saline) was immediately infused into the muscle. After 4 or 6 hours, the clamps were released, and the cremaster was placed in a pocket in the medial thigh for 24 hours. The muscle was then dissected, and microcirculatory measurements were made under intravital microscopy. Six animals were used in each of the four groups. All flaps exposed to 6 hours of ischemia, the duration considered to be critical ischemia, had no significant microcirculatory flow, regardless of treatment with VEGF. In the 4-hour ischemia group, or subcritical ischemia group, red blood cell velocity in arterioles was 14 mm/sec in muscles treated with VEGF and 9 mm/sec in controls (p = 0.02), and capillary flow was 7 per high-power field in muscles treated with VEGF versus 2 per high-power field in controls (p = 0.0005). Thus, VEGF did not alter microcirculatory flow in a muscle flap exposed to critical ischemia, but it did enhance flow to a flap exposed to subcritical ischemia.
The standard rat epigastric artery flap has been a very reliable model for flap research. The purpose of this study was to describe a modified design of this flap that included only the medial branch of the epigastric artery. Axial-pattern epigastric island skin flaps, measuring 8 x 8 cm, were raised in two groups of Sprague-Dawley male rats. In group A (N = 20) the vascular pedicle consisted of the main trunk of the epigastric vessel and both medial and lateral branches. In group B (N = 20) the flap was based solely on the medial branch of the epigastric artery, excluding the large lateral branch. The flaps were elevated and then sutured back to their beds. Flap survival was studied and the amount of viable skin in both groups was compared 1 week later. The rats were photographed using a digital camera and the images were analyzed using imaging software. The mean percentage surviving flap area in group A was 86.24% and in group B it was 69.72%, which is statistically significant (p < 0.001). We believe that this flap model, with its new modified design that includes a larger flap and inclusion of only the medial branch, will broaden its application to microsurgery. The main advantage of this flap over the conventional epigastric flap is that in this model it is possible to achieve predictable and consistent necrosis in the random extension of the flap.
Angiosomes are blocks of tissues, composed of the integument and underlying deep structures, supplied and drained by a named artery and its accompanying vein. The purpose of the current study is to describe a new principle, which allows extension of the territory of an angiosome into the adjacent angiosome, thus enabling the creation of a large skin flap (arteriovenous cross-flow flap). Epigastric skin flaps, measuring 8 x 8 cm, were raised in 30 Sprague-Dawley male rats. In group A (single-pedicle flap), the flaps were based on the epigastric artery and vein on the ipsilateral side, and the contralateral pedicle was divided. In group B (cross-flow flap), the epigastric vein on the ipsilateral side and the epigastric artery on the contralateral side of the flap were divided. In group C (skin graft), the vascular pedicles were divided bilaterally. A definitive assessment was made on the seventh day. Digital images of the flaps were analyzed using an imaging software and the areas of skin survival and necrosis were determined. Lead oxide microangiogram was performed in another set of flaps both acutely and 1 week after flap elevation. The percent survival flap area in group A was 69.94, in group B was 89.07, and in group C was 13.00. All the groups are statistically different, with a p value < 0.001. The microangiograms showed striking differences in the vascular pattern in the cross-flow and the single-pedicle flaps. It is clearly demonstrated that the arteriovenous cross-flow flaps have increased survival of skin when compared with the conventional axial-pattern flaps.
Fibrin glue has been used by several researchers to seal microvascular anastomoses sites. Usually the glue is delivered at the site with a syringe and needle. However, this technique can result in excess deposition of glue, which can cause intravascular thrombosis and can harden the vessel wall. We describe a new technique that avoids both these problems. We designed a "paintbrush" by inserting a suture through the syringe needle and then using the suture tip as a brush to apply the fibrin glue. End-to-side anastomoses were performed between the femoral artery and femoral vein in ten rats. Only two sutures were used to perform the anastomosis, the rest of the anastomosis being completed by sealing the gaps with fibrin glue. All the anastomoses were patent after 2 weeks, and no thromboses occurred. This is a new method for applying fibrin glue that delivers an adequate amount of fibrin glue without causing thrombosis.
Conventional methods of microvascular anastomosis using sutures cause vessel narrowing, foreign body reactions, and intravascular thrombosis. Although fibrin glue seems to be the ideal material to perform a microvascular anastomosis, its success has been limited. Excess fibrin used in some of the earlier methods has caused vessel narrowing and intravascular thrombosis. We evaluated the quality of end-to-side anastomosis using fibrin glue applied with a new technique and minimal sutures, and compared the results to those obtained with a standard suture technique. End-to-side anastomosis of femoral vessels was performed in 32 male Sprague-Dawley rats. Fibrin glue was topically applied at the anastomotic site, after inserting only two corner sutures. The fibrinogen component obtained from single donor human cryoprecipitate, was combined with bovine thrombin (500 IU per milliliter). In the control group (N = 16), the anastomosis was performed using eight to ten interrupted 10/0 nylon sutures. Fibrin glue-assisted anastomosis took less time, caused less bleeding at the anastomotic sites, and achieved a patency rate comparable to that provided by the suture technique. We have shown that a new, atraumatic technique of microvascular anastomosis with cryoprecipitate-thrombin glue and only two sutures, can produce excellent patency rates. This technique is easy to perform, inexpensive, and does not involve new equipment.
Current evidence suggests that neovascularization is mediated by a wide range of angiogenic growth factors. Vascular endothelial growth factor (VEGF) appears to be one of the most important angiogenic factors in vivo. The aim of this project was to evaluate the efficacy of VEGF in augmentation of blood supply to skin flaps. Epigastric skin flaps were raised in 16 Sprague-Dawley male rats. In group A (N = 8), 5 micrograms of VEGF was injected into the epigastric artery after flap elevation. In the control, group B (N = 8), the artery was injected with saline. On the seventh day, the rats were photographed and the digital images were analyzed using imaging software (Image-Pro Plus 1.2). The blood flow in the flaps was measured with a percutaneous laser Doppler probe at specific locations. Histological studies of the flaps were done. Results showed that the mean percentage surviving flap area was 71.9% in group A and 53.7% in the control group, which is statistically significant (p < 0.001). Histological examination revealed increased density of the capillaries in the flaps treated with VEGF when compared to the control group. We believe the increase in skin survival is due to angiogenesis induced by the VEGF.
Dehydroepiandrosterone (DHEA) has been reported to exert antiglucocorticoid activity. When administered to obese, hypercorticosteronemic Zucker rats, it causes a diminution of food intake and a reduction in their rate of weight gain. This experiment was conducted to evaluate whether this biologic effect could be ascribed to chronic adrenal insufficiency. Obese and lean Zucker rats were treated with DHEA as a food supplement for 28 days. Upon sacrifice, organ weights and serum chemistries were measured, along with neurotransmitter levels in regions of the hypothalamus. Results showed that although the obese animals gained weight more slowly, had lower insulin levels, and ate less, their serum glucose, corticosterone, and ACTH levels were not different from control. Hypothalamic neurotransmitters in the obese rat were unaffected by chronic DHEA treatment. We concluded that, although DHEA clearly affects Zucker weight gain, it does not induce chronic adrenal insufficiency.
An experiment was carried out to show the patency rates of microsurgical carotid artery bypasses with femoral artery grafts, using a single-cut arteriotomy in rats. A bypass was done on 127 Sprague-Dawley rats. Of these, 125 were patent after 20 min, and all of these were patent after the animals were sacrificed at 3 days, for a 98 percent patency rate. The method of performing the arteriotomies, as well as the bypass itself, is described. The benefits of using the end-to-side anastomosis are explained. The authors conclude that the single-cut arteriotomy is convenient and easy to perform. The end-to-side anastomosis is a worthwhile technique and should encourage the proficiency of every student of microsurgery.
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The Wellcome Tropical Institute has assisted countries in the tropics to establish viable systems of continuing medical education, particularly for young doctors practising in rural areas. As part of this strategy the Institute has developed material for use in distance learning. The first attempt to apply the problem-based learning approach to written material for use by an individual learner in the absence of a tutor led to a trial in Ghana, Kenya and Pakistan to compare a conventionally designed module with a problem-based learning module on the same topic for their respective acceptability, effectiveness and efficiency. The design, implementation and results of these three comparative trials are presented.
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In recent years, the possible role of occupational solvent exposure as a cause of chronic effects on the brain has been a matter of increasing concern. The present study was undertaken with the purpose of further investigating this problem, trying to minimize confounding owing to effects of recent solvent exposure and a 'healthy worker' effect. This was accomplished by studying a historical cohort of painters. The material consists of a random sample of 85 painters, and as a non-exposed control group of 85 bricklayers, selected in the same way. Parts of the study are based on this sample supplemented by a sample of 9 painters and 14 bricklayers, selected among subjects with a high degree of complaints on mental impairment. On the basis of a detailed interview on previous solvent exposure, the painters were divided into three groups with low, medium and high solvent exposure, respectively. As signs of organic brain damage we used the degree of dementia and performance in psychometric tests as assessed at a neuropsychological examination; the degree of dyscoordination as assessed from clinical neurological tests; and the degree of cerebral atrophy as assessed from CT-scans of the brain. CT-scans were performed only on a specially selected subsample. The degree of dementia, dyscoordination, and cerebral atrophy increased significantly with the degree of solvent exposure. A similar, but non-significant association was found for the relation between performance in psychometric tests and solvent exposure. The degree of dementia, of dyscoordination, and of cerebral atrophy were positively associated with each other, suggesting that they reflect different aspects of a common underlying factor, an organic brain damage. A review of the literature compared with the results of the present study suggests that a number of studies may have been biased towards negative findings owing to the inclusion in the study material of large proportions of subjects with a solvent exposure that is too little to increase the risk of an organic brain damage. Conflicting results between different studies on performance in psychometric tests may also arise from insufficient adjustment for primary intellectual level.(ABSTRACT TRUNCATED AT 400 WORDS)
In a 12-week double-blind study, oxiracetam (CGP 21690 E), a new nootropic drug, at a dose of 2.4 mg per day, was compared to placebo in the treatment of 106 middle-aged patients suffering from mild to moderate organic brain syndrome due to prolonged exposure to organic solvents. At the beginning of the study and after 12 weeks treatment, the patients underwent a battery of neuropsychological tests to determine their mental and memory functioning. A symptom questionnaire consisting of 21 items was rated pre-treatment, and improvement or worsening of any of the symptoms recorded monthly. At the end of the study a global evaluation was performed by the patients themselves, their relatives, the psychologist and the doctor. The code was not broken until the final writing of this paper. No statistically significant differences were observed between the treatment groups in any of the above-mentioned evaluations; neither were any differences in the neuropsychological tests performance observed. Thus, oxiracetam seems to have no effect in the treatment of organic brain syndrome.