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Biomedical subjects

A A Brown

Publications and source records attributed to A A Brown.

At least 19 recordsLinked to original sources
PubMed2004

Circumcision in 'buried penis'--a cautionary tale.

BACKGROUND: The aim of a circumcision is to remove sufficient foreskin from the penile shaft and preputial epithelium to uncover the glans. Removal of too much preputial skin may lead to an unsatisfactory cosmetic and functional result. Patients with a congenital anomaly known as 'buried penis' are particularly susceptible to this. In this condition, abnormal dartos fascial bands or muscle fibres tether the penile shaft and as a result conceal its true length. CASE REPORT: A 5-year-old boy underwent circumcision but his 'buried penis' was not recognised by the surgeon pre-operatively. Unfortunately, his penile shaft was left almost entirely denuded of skin as a result. The wound required a full thickness graft. Follow-up at 1 year has so far been satisfactory. CONCLUSIONS: This case highlights the importance of early recognition of a buried penis when considering circumcision. It demonstrates the abnormal anatomy of a buried penis and its management. It also provides a potential reconstructive option in cases of excess skin removal.

Child, Preschool↗
PubMed2002

Protective effects of recombinant human antithrombin III in pig-to-primate renal xenotransplantation.

Delayed rejection of pig kidney xenografts by primates is associated with vascular injury that may be accompanied by a form of consumptive coagulopathy in recipients. Using a life-supporting pig-to-baboon renal xenotransplantation model, we have tested the hypothesis that treatment with recombinant human antithrombin III would prevent or at least delay the onset of rejection and coagulopathy. Non-immunosuppressed baboons were transplanted with transgenic pig kidneys expressing the human complement regulators CD55 and CD59. Recipients were treated with an intravenous infusion of antithrombin III eight hourly (250 units per kg body weight), with or without low molecular weight heparin. Antithrombin-treated recipients had preservation of normal renal function for 4-5 days, which was twice as long as untreated animals, and developed neither thrombocytopenia nor significant coagulopathy during this period. Thus, recombinant antithrombin III may be a useful therapeutic agent to ameliorate both early graft damage and the development of systemic coagulation disorders in pig-to-human xenotransplantation.

Animals↗
PubMed2001

Molecular organization of the nodal region is not altered in spontaneously diabetic BB-Wistar rats.

We examined the organization of the molecular components of the nodal region in spontaneously diabetic BB-Wistar rats. Frozen sections and teased fibers from the sciatic nerves were immunostained for nodal (voltage-gated Na(+) channels, ankyrin(G), and ezrin), paranodal (contactin, Caspr, and neurofascin 155 kDa), and juxtaparanodal (Caspr2, the Shaker-type K(+) channels Kv1.1 and Kv1.2, and their associated subunit Kvbeta2) proteins. All of these proteins were properly localized in myelinated fibers from rats that had been diabetic for 15-44 days, compared to age-matched, nondiabetic animals. These results demonstrate that the axonal membrane is not reorganized, so nodal reorganization is not likely to be the cause of nerve conduction slowing in this animal model of acute diabetes.

Animals↗
PubMed2001

Acute facial-nerve paralysis with parotid adenolymphoma.

An 82-year-old woman presented with acute facial paralysis in association with parotid swelling following fine-needle aspiration cytology of a parotid adenolymphoma. Evacuation of a tense haematoma decompressed the nerve and led to complete recovery within 6 months. Additionally, the tumour is no longer evident, either clinically or radiologically, and fine-needle aspiration cytology appears to have been both diagnostic and, inadvertently, therapeutic in this case.

Adenolymphoma↗
PubMed2001

Dietary modulation of endothelial function: implications for cardiovascular disease.

The vascular endothelium is the primary site of dysfunction in many diseases, particularly cardiovascular disease. A variety of risk factors, including smoking, hypercholesterolemia, hyperhomocysteinemia, hypertension, and diabetes mellitus, adversely affect endothelial function. Emerging evidence suggests an important role of dietary factors in modulating endothelial function. In particular, n-3 fatty acids, antioxidant vitamins (especially vitamins E and C), folic acid, and L-arginine appear to have beneficial effects on vascular endothelial function, either by decreasing endothelial activation or by improving endothelium-dependent vasodilation in patients at high risk of cardiovascular disease as well as in healthy subjects. These effects may serve as one potential mechanism through which these nutrients reduce the risk of cardiovascular disease, as observed in epidemiologic studies and several clinical trials. This article reviews clinical and experimental evidence regarding the role of these nutrients in modulating endothelial function and their potential to prevent cardiovascular disease.

Antioxidants↗
PubMed2000

Renal xenografts from triple-transgenic pigs are not hyperacutely rejected but cause coagulopathy in non-immunosuppressed baboons.

BACKGROUND: The genetic modification of pigs is a powerful strategy that may ultimately enable successful xenotransplantation of porcine organs into humans. METHODS: Transgenic pigs were produced by microinjection of gene constructs for human complement regulatory proteins CD55 and CD59 and the enzyme alpha1,2-fucosyltransferase (H-transferase, HT), which reduces expression of the major xenoepitope galactose-alpha1,3-galactose (alphaGal). Kidneys from CD55/HT and CD55/CD59/HT transgenic pigs were transplanted into nephrectomised, nonimmunosuppressed adult baboons. RESULTS: In several lines of transgenic pigs, CD55 and CD59 were expressed strongly in all tissues examined, whereas HT expression was relatively weak and did not significantly reduce alphaGal. Control nontransgenic kidneys (n=4) grafted into baboons were hyperacutely rejected within 1 hr. In contrast, kidneys from CD55/HT pigs (n=2) were rejected after 30 hr, although kidneys from CD55/CD59/HT pigs (n=6) maintained function for up to 5 days. In the latter grafts, infiltration by macrophages, T cells, and B cells was observed at days 3 and 5 posttransplantation. The recipients developed thrombocytopenia and abnormalities in coagulation, manifested in increased clotting times and an elevation in the plasma level of the fibrin degradation product D-dimer, within 2 days of transplantation. Treatment with low molecular weight heparin prevented profound thrombocytopenia but not the other aspects of coagulopathy. CONCLUSIONS: Strong expression of CD55 and CD59 completely protected porcine kidneys from hyperacute rejection and allowed a detailed analysis of xenograft rejection in the absence of immunosuppression. Coagulopathy appears to be a common feature of pig-to-baboon renal transplantation and represents yet another major barrier to its clinical application.

Animals↗
PubMed2000

Prominent role of P-selectin in the development of advanced atherosclerosis in ApoE-deficient mice.

BACKGROUND: Adhesive interactions between leukocytes and endothelial cells are characteristic of the development of atherosclerotic lesions, but the receptors involved remain to be defined. P-selectin is an adhesion receptor expressed on activated endothelial cells or platelets and was shown to be involved in fatty streak formation in LDL receptor-deficient mice on an atherogenic diet. The main purpose of this study is to examine the role of P-selectin in the spontaneous development of advanced atherosclerosis in apoE-deficient mice. METHODDS AND RESULTS: We intercrossed P-selectin-deficient mice with mice lacking apoE and compared lesion development in apoE-deficient mice with P-selectin (apoE(-/-) P(+/+)) and without P-selectin (apoE(-/-) P(-/-)) that were fed normal mouse chow. At 4 months of age, apoE(-/-) P(-/-) mice had 3. 5-fold smaller aortic sinus lesions than apoE(-/-) P(+/+) mice. These were limited to fatty streaks in the apoE(-/-) P(-/-) mice, whereas 70% of apoE(-/-) P(+/+) lesions contained smooth muscle cells. Significantly more of the aortic sinus circumference was covered by lesions in the apoE(-/-) P(+/+) animals. The P-selectin genotype affected macrophage recruitment, because twice as many mononuclear cells were present in the P-selectin-positive lesions. At 15 months, the lesions progressed to the fibrous plaque stage in both genotypes and spread throughout the aorta, but this process was delayed in apoE(-/-) P(-/-) mice. In the aortic sinus, the lesions of the apoE(-/-) P(-/-) mice were 2.6-fold smaller and less calcified. CONCLUSIONS: P-selectin appears to be a key adhesion receptor mediating leukocyte recruitment into lesions and promoting advanced atherosclerosis in apoE-deficient mice.

Animals↗
PubMed1998

The combined role of P- and E-selectins in atherosclerosis.

P- and E-selectins are adhesion molecules mediating the first step in leukocyte extravasation. Because their function in leukocyte adhesion is overlapping, we hypothesized that there might be a combined effect of these selectins on the development of atherosclerotic lesions. We bred P- and E-selectin-double-deficient mice onto the low-density lipoprotein receptor (LDLR)-deficient background (LDLR-/- P/E-/-) and compared lesion development in these mice to that in mice wild type for both selectins (LDLR-/- P/E+/+). After 8 wk on atherogenic diet, the LDLR-/- P/E-/- mice developed fatty streaks in the aortic sinus that were five times smaller than those in LDLR-/- P/E+/+ mice. The density of macrophages in the fatty streaks was comparable between LDLR-/- P/E+/+ and LDLR-/- P/E-/- mice. After 22 wk on the diet, the lesions spread throughout the aorta but this process was delayed in LDLR-/- P/E-/- mice. At 37 wk on diet, the lesions progressed to the fibrous plaque stage in both genotypes. However, the lesions in the aortic sinus in LDLR-/- P/E-/- mice were 40% smaller and less calcified than those of LDLR-/- P/E +/+ mice. Our results suggest that P- and E-selectins together play an important role in both early and advanced stages of atherosclerotic lesion development.

Animals↗
PubMed1992

Haematological splenectomy. Changing indications and complications.

Review of splenectomies carried out for haematological disease over a ten-year period, at a district hospital, shows that the indications for splenectomy have changed substantially over this time. Fewer patients with idiopathic thrombocytopenic purpura now require splenectomy, however its role in the management of lymphoproliferative disorders has expanded. Splenectomy remains an important therapeutic option for a range of haematological disorders: this series shows it to be a safe and effective operation in selected patients, although it is not without both short and long-term sequelae.

Adolescent↗
PubMed1987

Soft tissue gliomatosis--heterotopic glial tissue in the subcutis: a case report.

A subcutaneous nodule composed of heterotopic glial tissue is reported. The lesion was present in the subcutaneous tissue of the chest wall in a 2-year-old female. Histologically it was composed of loosely textured fibrillary neuroglial tissue in a densely hyalinized collagenous stroma. Immunohistochemical staining for glial fibrillary acidic protein was positive. The possible origin of this soft tissue glial heterotopia is discussed and the subject of heterotopic glial tissue is reviewed.

Axilla↗
PubMed1981

Experience with the EEA stapler in carcinoma of the lower rectum.

The lower rectum is defined and the overall management of carcinoma in this area is considered with regard to operations available, whether these operations are equally radical, and the problem of continence. The various types of low anterior resection are mentioned and the use of EEA stapling device is described. Personal experience with this instrument is reviewed, with special regard to the 'learning curve', the avoidance of colostomies, the technique, and the complications.

Colostomy↗
PubMed1979

Colonoscopy in lower gastro-intestinal haemorrhage.

The value of colonoscopy in the diagnosis and management of lower gastro-intestinal haemorrhage was assessed in 107 patients who were examined during a 2-year period. The main indications were to define uncertain radiological findings, to further investigate the cause of bleeding in patients with normal barium studies and to carry out polypectomy. Radiological lesions were confirmed in 27, defined in 12, and refuted in 14 patients. Twenty-eight lesions were demonstrated on colonoscopy which were not diagnosed by barium enema or sigmoidoscopy. A diagnosis was made by colonoscopy in more than two-thirds of the patients with frank blood loss and normal radiographs. In cases of occult bleeding it was farless helpful. Colonoscopy significantly improved diagnosis and management of gastro-intestinal bleeding when the cause was in doubt after standard investigations. In addition, 37 polyps were removed through the colonoscope from 30 patients.

Gastrointestinal Hemorrhage↗