Biomedical subjects

R Botha

Publications and source records attributed to R Botha.

6 recordsLinked to original sources

PubMed2006

Anatomical considerations of the anterior approach for central venous catheter placement.

Central venous catheterization (CVC) entails the catheterization of the superior vena cava via either the subclavian or the internal jugular vein (IJV). This study looked at the frequency in which a needle was inserted into the IJV using the anterior CVC approach, which entails inserting the needle into the apex of Sedillot's triangle, formed by the sternal and clavicular heads of sternocleidomastoid (SCM). The ipsilateral distances from the apex of Sedillot's triangle to the superior aspect of the sternoclavicular joint and the diameter of the IJV were also measured. A needle was inserted into the apex of Sedillot's triangle in 36 adult cadavers with mean age of 62 +/- 19 years (mean +/- SD), mean height of 1.6 +/- 0.18 m, and a mean weight of 55 +/- 16 kg. Subsequent dissections of this area revealed the relation of the needle to the IJV. Results indicate that on the right, the needle was inserted into the IJV in 97.14% of the cases. On the left, the needle entered the IJV in 78.79% of the cases. From the sternoclavicular joint, the apex of Sedillot's triangle was found to be 40.87 +/- 1.62 mm and 38.73 +/- 6.34 mm on the right and left, respectively. The IJV diameter was 17.29 +/- 1.07 mm on the right and 15.30 +/- 0.25 mm on the left. We conclude that the anterior CVC approach is an anatomically accurate technique. It is furthermore important to realize that when performing any invasive procedure, a sound anatomical knowledge of the region is extremely important, as complications are often due to lack of understanding or misunderstanding of the relevant anatomy.

Adult↗

PubMed2000

Development of early melanocytic lesions in transgenic mice predisposed to melanoma.

We have previously described a line of transgenic mice (TG3) that spontaneously develops heritable malignant melanoma. Histological analysis of these animals during the first postnatal month is described here. In the TG3 line, the number of melanocytes is increased at all anatomical sites to which neural-crest-derived melanocytes normally migrate. Clonal expansion and morphological changes of these melanocytes can be detected as early as postnatal day (PND) 15. By PND 30, cells morphologically indistinguishable from the tumor cells of adult transgenic mice were detected in the ear, eye lid and perianal region. These cells are believed to be the precursors of the primary tumors in adult mice. The stepwise development of melanoma in the TG3 line is similar to the stepwise development of melanoma in humans.

Animals↗

PubMed1998

Development of heritable melanoma in transgenic mice.

Transfer of genetic material into recipient cells by transfection has been used successfully to isolate genes responsible for particular phenotypic traits. By using this strategy, DNA fragments were isolated that when transfected into appropriate uncommitted cells will commit the recipient cells to undergo adipocyte differentiation. Transgenic mice were generated with one of the active DNA clones, Clone B. The transgenic mice were expected to display an adipocyte-related phenotype; however, the animals developed melanin containing tumors at a young age. Insertion of Clone B into the mouse DNA probably interrupted a gene(s) that is involved in the regulation of cell growth, specifically regulation of cell growth in melanin-producing cells. Histopathologic analysis of these mice showed dark spots on the ear lobes of the animals as early as 10-12 d of age. By 3 mo, in addition to the ear lobes, pigmented tumors could be observed in other organs. A significant number of these transgenic mice died within 1 y of age. The melanomas developed spontaneously in these animals in the absence of any known chemical carcinogen or ultraviolet radiation. This line of mice provides a way of identifying genes involved in regulation of cell growth control and differentiation. These mice also serve as a model system to investigate the molecular, genetic, and phenotypic characterization and development of melanomas.

Animals↗

PubMed1987

The value of Swan-Ganz catheterization and volume loading in preventing renal failure in patients undergoing abdominal aneurysmectomy.

A prospective analysis of 61 patients undergoing abdominal aneurysmectomy is presented. When compared with 87 historical controls we have shown that the incidence of hypotensive episodes (31 out of 62 patients in the original study compared with 13 out of 44 patients in the prospective analysis) is significantly reduced when fluid balance is monitored invasively using the pulmonary artery wedge pressure and keeping it at 10 mm H2O (p less than 0.03). Renal dysfunction, defined as a significant drop in urine output and a doubling of the serum creatinine, occurred in only 10% of patients compared with 33% in the controls (p less than 0.001). The decreased prevalence of renal failure accounts for the reduction in mortality noted (p less than 0.01). There were 27 deaths (31%) amongst the patients in the earlier study compared with 9 (15%) in the prospective analysis. The pathogenetic mechanisms responsible for the development of renal failure following surgical manipulation of the abdominal aorta are reviewed.

Abdomen↗

PubMed1976

Lymphocoeles in renal homograft recipients.

UNLABELLED: Seven lymphocoeles have complicated 158 cadaver and 18 related live donor transplants performed over six years. The purpose of this study is to review the clinical, diagnostic and therapeutic problems encountered with lymphocoeles at this centre. Presentation was insidious, delayed (50 days post-op), and manifested by one or more of the following: palpable rectal or supra-pubic mass; unilateral leg oedema; recurrent urine infections with radiographic evidence of obstruction; filling defect in bladder on routine IVP. Possible pathogenetic factors: transplants performed on side of functioning Scribner shunts (6/7 cases); severe rejection episodes with graft lymphatic leak (1/7 cases). Differentiation from urinomas, haematomas, perinephric abscesses or other causes of obstructive uropathy were facilitated by: needle aspiration; IVP and cystogram, serial ultrasound sonography. Lymphangiography was not used. Treatment was conservative in three, repeated aspirations were performed in two and formal drainage procedures were required in three patients. Repeated cyst aspirations resulted in serious infections in both patients. Marsupialisation into the peritoneal cavity failed in one. CONCLUSIONS: 1) The graft should be anastomosed on side opposite a functioning shunt. 2) Lymphocoeles have an occult presentation and should be actively sought for as they may produce urinary obstruction. 3) Serial ultrasound is an excellent method of diagnosis and follow-up. 4) Unless urinary obstruction is present management should be conservative as spontaneous resolution may occur. 5) Ideal surgical management is problematical. Repeated needle aspirations should be approached with caution. Lymphocoeles are an uncommon but well documented complication of renal transplantation (Schweizer et al, 1972; Koehler et al, 1972; Christiansen et al, 1974; Rashid et al, 1974). They represent definite hazards and can either directly or indirectly contribute to morbidity or even mortality in the post-transplant patient. They must be differentiated from other pelvic masses such as urinomas, haematomas and perinephric abscesses as they all require different modes of treatment. As a rule, the diagnosis of one from another is straightforward, but as certain clinical features are shared, differentiation can on occasions be more difficult. In order to clarify some of these problems and outline a mode of therapy, a study was carried out in patients who have presented with lymphocoeles in our unit.

Adult↗

PubMed1974

Colonic ileus.

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Colonic Diseases↗