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Biomedical subjects

A J Botha

Publications and source records attributed to A J Botha.

18 recordsLinked to original sources
PubMed2006

Centralisation of oesophagogastric cancer services: can specialist units deliver?

INTRODUCTION: Oesophagogastric cancer surgery is increasingly being performed in only centralised units. The aim of the study was to examine surgical outcomes and service delivery within a specialist unit. PATIENTS AND METHODS: The case notes of all patients undergoing attempted oesophagogastrectomy between January 2000 and May 2003 were identified from a prospective consultant database. RESULTS: A total of 187 patients (median age, 63 years; range, 29-83 years; M:F ratio, 3.9:1) underwent attempted oesophago-gastrectomy. Of these, 91% were seen within 2 weeks of referral and treatment was instituted after a mean of 31 days (range, 1-109 days). More patients underwent surgery (63%) than neoadjuvant therapy (56%) within 1 month of referral. The main indication for surgery was invasive malignancy in 166 patients (89%). The 30-day mortality was 0.5% (1 death) and in-hospital mortality was 1.1% (2 deaths). The median length of hospital stay was 14 days (range, 7-69 days). Significant postoperative morbidity included: pulmonary complications (36%), cardiovascular complications (16%), wound infection (13%) and clinically significant anastomotic leaks (7%). Of the study group, 28 patients (15%) were admitted to ICU with a median stay of 10 days (range, 1-44 days); this accounted for 0.9% of ICU bed availability. Twelve patients (6.4%) were returned to theatre, most commonly for bleeding. The 1-year survival rates were 78%. During 2002-2003, national waiting list targets for both hernia repair and cholecystectomy were achieved. CONCLUSIONS: Despite recent increases in workload, high volume specialist units can deliver an efficient and timely service with both good treatment outcomes and minimal impact upon elective surgical waiting lists and ICU provision.

Adult↗
PubMed2004

Marginal adaptation of mineral trioxide aggregate (MTA) compared with amalgam as a root-end filling material: a low-vacuum (LV) versus high-vacuum (HV) SEM study.

AIM: To compare the marginal adaptation of mineral trioxide aggregate (MTA) or amalgam root-end fillings in extracted teeth under low-vacuum (LV) versus high-vacuum (HV) scanning electron microscope (SEM) viewing conditions. METHODOLOGY: Root-end fillings were placed in 20 extracted single-rooted maxillary teeth. Ten root ends were filled with MTA and the other 10 root ends were filled with amalgam. Two 1 mm thick transverse sections of each root-end filling were cut 0.50 mm (top) and 1.50 mm (bottom) from the apex. Gap size was recorded at eight fixed points along the dentine-filling material interface on each section when uncoated wet (LV wet (LVW)) and dry under LV (0.3 Torr) in a JEOL JSM-5800 SEM and backscatter emission (LV dry uncoated (LVDU)). The sections were then air-dried, gold-coated and gap size was recorded once again at the fixed points under HV (10(-6) Torr; HV dry coated (HVDC)). Specimen cracking, and the size and extent of the crack were noted. RESULTS: Gap sizes at fixed points were smallest under LVW and largest under HVDC SEM conditions. Gaps were smallest in MTA root-end fillings. A General Linear Models Analysis, with gap size as the dependent variable, showed significant effects for extent of crack in dentine, material and viewing condition (P = 0.0001). CONCLUSIONS: This study showed that MTA produced a superior marginal adaptation to amalgam, and that LVW conditions showed the lowest gap size. Gap size was influenced by the method of SEM viewing. If only HV SEM viewing conditions are used for MTA and amalgam root-end fillings, a correction factor of 3.5 and 2.2, respectively, may be used to enable relative comparisons of gap size to LVW conditions.

Aluminum Compounds↗
PubMed1999

Morphology of rhinoceros platelets.

Basic hematological information about rhinoceros species is limited. In this study, we have determined the platelet counts and described the platelet morphology of free-living white (Ceratotherium simum) and black (Diceros bicornis) rhinoceros using light and electron microscopy. The platelet counts of the two species were similar, but there were significant differences in platelet size as well as morphology between the species. The presence of large, nondiscoid platelet forms, resembling proplatelet or stress platelet forms, were observed in both, although not as often in the white rhinoceros as in the black rhinoceros.

Animals↗
PubMed1998

Oral colonization is unlikely to play an important role in Helicobacter pylori infection.

BACKGROUND: This clinical and microbiological study investigated whether Helicobacter pylori colonizes the mouth en route to the pyloric antrum. It has been suggested that oral colonies are a source of reinfection after eradication of gastric infection. METHODS: Some 208 patients attending for routine diagnostic endoscopy for dyspepsia were recruited. Before endoscopy, samples were collected of saliva, supragingival and infragingival plaque, and swabs were taken from the tongue, mouth and pharynx. At endoscopy, gastric antral biopsies were taken for the rapid urease test, culture and histological examination. Gastric and duodenal juice samples were aspirated. Restriction nuclease digestion with HaeIII was employed on all specimens from patients in whom there was evidence of the organism in the mouth. RESULTS: H. pylori was observed in dental plaque in only 15 patients, all from the 116 who had evidence of the organism in the stomach. Restriction endonuclease digestion demonstrated that in 13 of the 15 patients the strains were identical in mouth and stomach. CONCLUSION: Oral colonization is a rare event, but does occur. Its rarity suggests that it is not an important factor in reinfection.

Dyspepsia↗
PubMed1997

Base deficit after major trauma directly relates to neutrophil CD11b expression: a proposed mechanism of shock-induced organ injury.

OBJECTIVE: To determine whether expression of neutrophil integrin receptors is related to the degree of post-traumatic shock. DESIGN: Data were collected prospectively on patients with major trauma admitted to the surgical intensive care unit. SETTING: Denver General Hospital, Colorado. PATIENTS AND PARTICIPANTS: 17 severely injured adults. MEASUREMENTS AND RESULTS: The mean fluorescence intensity and per cent positive of neutrophil integrin receptors CD11 b, CD18 and CD11 a, and systolic blood pressure, blood transfusion, lactate and base deficit as indices of shock. CD11 b expression on circulating neutrophils was increased 6 and 12 h after trauma. After correcting for the other shock indices, base deficit predicted CD11 b expression at 12 h. CD11 b expression was negatively correlated with the circulating neutrophil count. CONCLUSIONS: The degree of metabolic acidosis after trauma correlates directly with CD11 b receptor expression on circulating neutrophils. This relation may be the mechanism whereby post-traumatic shock results in neutrophil sequestration and neutrophil-mediated organ injury and failure.

Acidosis↗
PubMed1997

Impala, Aepyceros melampus, platelets: count, morphology, and morphometric observations.

There is little published information regarding the platelets of impala (Aepyceros melampus). In this study we determined the platelet counts of 12 healthy adult male impalas and describe the morphology of the platelets. The platelet counts of the animals are high. Although the platelets appear to be extremely small, they have the characteristic ultrastructure of the platelets of the family Bovidae. They have few but prominent alpha-granules. Other cytoplasmic inclusions are the dense bodies, microtubules, mitochondria, and glycogen. There is no surface-connecting canalicular system present.

Animals↗
PubMed1996

Ultrastructure of buffalo, Syncerus caffer, platelets: comparison with bovine and human platelets.

Platelets are found in the blood of all mammals and serve the same basic hemostatic functions in all. Species differences in the morphology and activities of platelets in human and domesticated animals have been observed, but there is little published information regarding the blood pictures of wild animals. In this study, the ultrastructure of buffalo platelets was compared with that of bovine and human platelets. Buffalo platelets were found to be smaller than human platelets and intracellularly had larger alpha-granules, possessed distinctive dense granules and a more distinct microtubuli system, but they lacked the open canalicular system observed in the human type. This morphology is similar to that of cattle platelets.

Animals↗
PubMed1996

Sequential systemic platelet-activating factor and interleukin 8 primes neutrophils in patients with trauma at risk of multiple organ failure.

Plasma from 33 patients at risk of multiple organ failure (MOF) after major trauma was tested for a priming effect on neutrophils, and for the presence of platelet-activating factor (PAF) activity and interleukin (IL) 8. Plasma sampled at 3, 6, 12 and 24 h after injury significantly primed normal neutrophils to release mean(s.e.m.) 1.26(0.19), 1.33(0.26), 1.04(0.14) and 0.86(0.13) nmol superoxide per min per 1.3 x 10(6) neutrophils respectively (P < 0.05). Priming at 3 h after injury was inhibited by mean(s.e.m.) 63.8(7.0) per cent by the PAF antagonist, WEB 2170 (P < 0.01). Mean(s.e.m.) plasma IL-8 was raised at 6 and 12 h after injury to 785(183) and 836(175) pg/ml (P < 0.01). At 12 h after injury the plasma IL-8 level correlated directly with the number of units of red blood cells transfused (r = 0.64, P < 0.01), and was significantly higher in the group of six patients who developed MOF (P < 0.05). These data suggest that after trauma the mediators PAF and IL-8 appear sequentially in the circulation, are potential mechanisms of circulating neutrophil priming, and that IL-8 may also be an early biochemical marker predicting the onset of MOF.

Adolescent↗
PubMed1995

Postinjury neutrophil priming and activation: an early vulnerable window.

BACKGROUND: Generation of extracellular, cytotoxic superoxide anion (O2-) by polymorphonuclear neutrophils (PMNs) contributes to an unbridled inflammatory response that can precipitate multiple organ failure (MOF). Release of O2- is markedly enhanced when activated PMNs have been previously "primed" by inflammatory mediators, such as those expressed after trauma. We therefore hypothesized that PMN priming occurs as an integral part of the early inflammatory response to trauma. METHODS: PMNs were obtained from 17 high-risk patients with torso trauma at 3, 6, 12, 24, 48, and 72 hours after injury, as well as from 10 healthy donors, and the in vitro release of O2- was quantitated with a kinetic, superoxide dismutase (SOD)-inhibitable cytochrome c reduction assay. PMN O2- release was measured in the presence and absence of 1 mumol/L N-formyl-methionyl-leucyl-phenylalanine (fMLP) and after priming and activation with 20 nmol/L platelet-activating factor (PAF) and 1 mumol/L fMLP, respectively. RESULTS: In vitro PMN O2- release was used to determine whether postinjury PMNs were (1) activated in vivo, (2) primed in vivo, or (3) primable in vitro. Unstimulated PMNs from trauma patients spontaneously expressed modest amounts of O2- in vitro from 6 to 48 hours after injury, suggesting endogenous activation. Also, fMLP-activated PMNs collected between 3 and 24 hours after injury expressed more O2- than controls (p < or = 0.02), indicating in vivo, trauma-related priming. Furthermore, postinjury PMNs were maximally primed in vivo (i.e., in vitro exposure to PAF before fMLP activation failed to significantly enhance O2- release) as compared to PMNs treated with fMLP. CONCLUSIONS: These data indicate that major torso trauma (first hit) primes and activates PMNs within 3 to 6 hours after injury. Consequently, we postulate that postinjury priming of PMNs may create an early vulnerable window during which a second hit (e.g., a secondary operation or delayed hemorrhage) activates exuberant PMN O2- release, rendering the injured patient at high risk for MOF.

Adolescent↗
PubMed1995

Early neutrophil sequestration after injury: a pathogenic mechanism for multiple organ failure.

Polymorphonuclear neutrophils (PMNs) play a pivotal role in the inflammation that precedes multiple organ failure (MOF). In a rat model of MOF, PMNs become primed for enhanced superoxide anion (O2-) release and CD11b expression, sequester in end organs, and produce organ failure. Therefore, we hypothesized that circulating PMNs harvested in the first 24 hours after injury from trauma patients at risk for MOF would (1) exhibit a primed O2- release, (2) upregulate CD11b expression, and (3) show evidence of sequestration in tissues. Extracellular PMN O2- release and CD11b receptor expression were measured at 3, 6, 12, and 24 hours after injury in 33 torso trauma patients with Injury Severity Scores > 15; eight patients (24%) developed MOF. Healthy adults served as controls. PMNs after injury were primed for enhanced in vitro O2- release at 3, 6, 12, and 24 hours after injury, indicating prior in vivo priming. CD11b expression was also increased at 6, 12, and 24 hours after injury. Circulating PMN numbers increased sharply at 3 hours after injury, before decreasing dramatically at 6 and 12 hours, suggesting end organ sequestration. At 12 hours after injury, declines in circulating PMNs were significantly greater in MOF than in non-MOF patients (p < 0.05). These data indicate that PMNs are quickly mobilized into the circulation after injury and then primed for enhanced O2- release and CD11b expression. PMN priming appears to be a necessary preamble to PMN sequestration in patients with major torso trauma. Upregulation of PMN function, accompanied by subsequent end organ sequestration, may represent an important early event in the pathogenesis of MOF after injury.

Adult↗
PubMed1995

Postinjury neutrophil priming and activation states: therapeutic challenges.

Both hyperactivity and hypoactivity of neutrophils (PMNs) have been implicated in the pathogenesis of postinjury multiple organ failure. In this paper, the cellular and molecular mechanisms involved in the regulation of PMN O2- production are reviewed. In addition, relevant research laboratory techniques for measuring both intracellular and extracellular O2- release are outlined. In a pilot study PMN O2- release in response to a battery of PMN agonists was determined, and four functional states of the NADPH were defined: resting, primed, activated, and unresponsive. PMNs from normal adult volunteers are in the resting state. In contrast, PMNs from patients with severe torso trauma are primed and activated in the first 24 h postinjury, but, after 48 h, become unresponsive to both receptor-dependent (platelet activating factor and N-formyl-methyl-leucyl-phenylalanine) and receptor-independent (phorbol 12-myristate 13-acetate) activation. The ability to identify at-risk patients and provide a rationale for ameliorating PMN-mediated tissue injury in patients with hyperinflammation syndromes are discussed. In addition, the importance of identifying patients with PMNs that are unresponsive, and the necessity for increasing PMN function in these patients in order to reduce the risk of sepsis, are also discussed.

Humans↗
PubMed1995

Laparoscopic appendicectomy: a trainee's perspective.

Minimally invasive surgery is rapidly becoming an integral part of general surgery. Many general surgeons have been trained to undertake laparoscopic cholecystectomy. It has been recommended that laparoscopic appendicectomy should be the training operation for junior surgeons. The aim of our study was to assess whether laparoscopic appendicectomy training can safely be introduced to junior surgeons in a district general hospital. During the 11 month study period, 27 laparoscopic and 38 open appendicectomies were performed. The median anaesthetic time was 80 min for laparoscopic and 52.5 min for open appendicectomies. Laparoscopic appendicectomies cost, on average, 618 pounds and open appendicectomies 770 pounds per case. The complication rate between the two procedures was equal. We therefore showed that laparoscopic appendicectomy by junior surgeons is both safe and cost-effective. Although the registrar did most of the laparoscopic appendicectomies, with resultant less operating for the SHO, laparoscopic appendicectomy provided the SHO with training in diagnostic laparoscopy and laparoscopic dissection. We conclude that basic laparoscopic training should be introduced early in surgical training, after which laparoscopic appendicectomy is a safe procedure for surgical trainees.

Adolescent↗
PubMed1992

The Royal London Hospital Helicopter Emergency Medical Service: first phase 1990.

A Helicopter Emergency Medical Service (HEMS) has been introduced to improve trauma care in the Southeast of England. The majority of the workload comes from the area bounded by the M25 ring road. In 1989 a Dauphin 365N helicopter equipped for pre-hospital primary rescue and emergency inter-hospital secondary transfer was certified by the Civil Aviation Authority. The helicopter commenced carrying patients with a paramedic and a doctor on board early in 1990. In September 1990 this service was further improved by the opening of a helipad at the Royal London Hospital and a designated HEMS desk at London Ambulance Service central control. Eighty-four patients were transported in primary rescue missions and 107 as emergency transfers in 1990.

Aircraft↗
PubMed1991

Endometriosis in gluteus muscle with surgical implantation. A case report.

Intrapelvic endometriosis is a fairly common condition affecting women during their reproductive years. Extrapelvic disease is, however, very rare. We report a case where an endometrioma was found in the body of the gluteus minimus muscle, and endometrial tissue was implanted in the wound at the time of excision.

Adult↗