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Biomedical subjects

S R Thomson

Publications and source records attributed to S R Thomson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Isolation and characterization of chicken TaxREB107, a putative DNA binding protein abundantly expressed in muscle.

Myogenic regulatory factors (MRFs) are vital transcription factors that act at multiple points during development to establish the skeletal muscle phenotype. This class of muscle-restricted, basic helix-loop-helix (bHLH) proteins acts in concert with additional transcriptional modulators to precisely control muscle gene expression. We have isolated the chicken homologue of Tax responsive element binding protein 107 (TaxREB107). The cDNA is 83% homologous at the amino acid level to human and mouse TaxREB107 and contains a centrally located leucine zipper motif. Northern analysis demonstrated that the gene is expressed in multiple tissues including skeletal muscle. Immunofluorescent staining revealed that the cTaxREB107 protein is located in both the nuclear and cytoplasmic compartments. Distinct localization to the nucleoli supports the evidence that TaxREB107 is a ribosomal protein. Because TaxREB proteins also are implicated in transcriptional regulation, we overexpressed cTaxREB107 in embryonic myoblasts. cTaxREB107 increased troponin I reporter gene activity as well as MRF-directed transcription from a multimerized skeletal muscle E-box reporter gene (4Rtk-luc). However, cotransfection of expression plasmids coding for MyoD and cTaxREB107 did not produce an increase in 4Rtk-luc suggesting that cTaxREB107 enhances myogenic gene transcription through a means independent of a physical association with MyoD. In conclusion, our results define a role for cTaxREB107 during avian myogenesis as a positive modulator of skeletal muscle gene expression.

Amino Acid Sequence↗
PubMed2001

The effect of a GnRH antagonist on endocrine and seminal parameters in stallions.

Relatively little is known about endocrine control of reproduction in the stallion, but gonadotropins are thought to be central in regulating spermatogenesis and libido. The ability to effectively antagonise GnRH, and thereby gonadotropins, is therefore important both in further investigations of hormonal control of reproduction in stallions, and for clinical applications. In the present study four pony stallions were treated with a potent GnRH antagonist, Antarelix. Their libido, seminal parameters, and hormonal profiles were compared with those recorded before administration of the antagonist. Plasma concentrations of gonadotropins, testosterone and estradiol decreased by 48 h after antagonist administration, with estradiol and FSH being most consistently suppressed, and remained at reduced concentrations for 4 weeks. Spermatozoal motility, numbers and morphology were not significantly affected by treatment, but increasing numbers of round spermatogenic cells were seen in the ejaculate as the trial progressed. Libido was assessed by the time taken for the stallions to regain an erection in the presence of a mare after ejaculation (refractory period). The refractory period increased significantly after treatment. When the stallions were castrated 8 weeks after antagonist treatment, histological evidence of testicular degeneration was present. We concluded that use of this antagonist showed promise as a valuable research tool in modulating changes in circulating hormone concentrations in stallions. Reversibility of the effects on libido and testicular changes need further investigation.

Animals↗
PubMed2001

Internal drainage of pancreatic pseudocysts in children using an endoscopically-placed stent.

Persistent pseudocysts, which are rare in children, have traditionally been managed by open surgery. We describe two children who presented with large, established pseudocysts of the pancreas. They were successfully treated in the short term by minimally-invasive stent placement to create an internal cyst-gastric communication. This approach merits comparison with open surgical techniques.

Child↗
PubMed2001

Penetrating chest injuries in the firearm era.

BACKGROUND: firearm wounds of the chest are now common at our institution. The management algorithm for firearm wounds has not been evaluated for this mode of injury. METHODS: records of all patients with penetrating chest injuries admitted to an urban tertiary hospital over 1 year were retrieved and analysed. RESULTS: there were 473 stab and 116 firearm wounds. In comparison to stab injuries firearm wounds had significantly more normal X-rays (14 vs. 5%), fewer pneumothoraces (15 vs. 37%), and more contusions (43 vs. 2%). The frequency of haemothoraces (34 vs. 23%) and haemopneumothoraces (36 vs. 35%) was similar in both groups. Stabbing caused all the 18 cardiac injuries. Associated abdominal injuries occurred in 8% of stab and 34% of firearm injuries. Pneumothoraces due to firearms were uncommon and rarely required drainage. More pneumothoraces were treated nonoperatively among firearm injuries in contrast to stabbing injuries where the opposite applied. The management of haemothorax and haemopneumothorax was similar in both groups that fulfilled the criteria for drainage. The rate of ICU admission was higher and the hospital-stay longer following firearm injuries. Fifty-nine patients died (10% of the total), 33 (28%) from the firearm injuries and 26 (6%) from stab-wounds. Early deaths were 1 and 3% for stabs and firearms, respectively. CONCLUSIONS: patients with firearm injuries reaching hospital suffered three times higher mortality and a longer ICU and hospital stay than those with stab injuries. However, early mortality was similar for both modes of injury and validates the continued application of the stab wound derived management algorithm to all modes of injury.

Adolescent↗
PubMed2000

Control of follicular development and luteal function in the mare: effects of a GnRH antagonist.

Control of the equine estrous cycle was studied by suppressing gonadotropin secretion by administration of a GnRH antagonist to cyclic pony mares. Four mares received vehicle (control cycle) or a GnRH antagonist, Antarelix (100 microg/kg) on Day 8 of diestrus, and blood samples were collected at 15-min intervals from 0 to 16 h, 24 to 36 h, and daily until the next ovulation. Ovarian activity was monitored by transrectal ultrasonography, and measurement of plasma concentrations of progesterone and estradiol. Antagonist treatment eliminated large diestrous pulses of LH. Progesterone concentrations had fallen significantly in all mares by the day after treatment and, in three of the four mares, remained low until luteolysis. However timing of luteolysis (ie., progesterone concentrations <1 ng/mL) was not affected by antagonist treatment. The preovulatory surges of estradiol and LH were significantly delayed in the treatment cycle, as was the appearance of a preovulatory follicle >30 mm. Cycle length was significantly longer during the treatment than the control cycle. These results show that treatment of diestrous mares with a GnRH antagonist attenuated progesterone secretion, indicating a role for LH in control of CL function in the mare, and delayed ovulation presumably because of lack of gonadotropic support.

Animals↗
PubMed2000

Abdominal content containment: practicalities and outcome.

BACKGROUND: Alternatives to fascial closure of the abdominal wall are increasingly used in critically ill patients. They pose practical and logistical problems in management which are described in this single-institution study. METHODS: Between January 1994 and December 1997, 157 predominantly young male patients (100 trauma and 57 non-trauma) underwent temporary abdominal content containment (t-ACC) using plastic bags or polyglactin mesh. Indications for t-ACC were severe sepsis requiring reoperation, abdominal compartment syndrome, abdominal wall tissue loss or a combination of these. A total of 385 laparotomies were performed. RESULTS: Two t-ACC procedures failed owing to technical error and two were complicated by enteric fistulas. Six patients underwent early definitive abdominal closure within 15 days. The remaining survivors had a protracted hospital stay (mean(s.d.) 44.6(26.6) days) and all developed incisional hernias which were challenging to repair. The overall mortality rate was 44 per cent. CONCLUSION: Plastic bags were cheaper and as effective as polyglactin mesh for t-ACC. Survivors require a multidisciplinary approach in management, undergo a protracted hospital stay and later need complex incisional hernia repairs.

Abdominal Injuries↗
PubMed2000

The management of sigmoid volvulus.

The epidemiology and clinical pattern of sigmoid volvulus are well defined. Although clinical manifestations of acute volvulus are often clear-cut, diagnostic doubt is not uncommon and, if gangrene supervenes, mortality rises appreciably. While gangrene requires resectional surgery, the management of the viable colon related to a volvulus episode has a variety of options. These, particularly non-resectional alternatives, require more critical reappraisal in the light of advances in minimally invasive techniques.

Acute Disease↗
PubMed2000

Detection of steroidogenic acute regulatory protein in equine ovaries.

A steroidogenic acute regulatory (StAR) protein has been identified in several species as a probable important rate-limiting step in steroidogenesis. This protein is believed to be responsible for transporting cholesterol from the outer to the inner mitochondrial membrane. It is known that equine chorionic gonadotrophin (eCG) stimulates steroidogenesis in the corpora lutea of early pregnant mares and that eCG also upregulates StAR mRNA in bovine ovaries. In the present study, ovarian tissue from cyclic and early pregnant mares was immunostained to detect the distribution of the StAR protein. Western blot analysis was performed, followed by phosphor imaging to establish whether the onset of eCG secretion in pregnancy was associated with increased expression of the StAR protein. Immunostaining for StAR was confined to the theca interna of growing and preovulatory follicles, but 24 h after treatment with hCG, some granulosa cells were positively stained. Positive staining was confined to the large luteal cells of the equine corpus luteum. There was no difference in the distribution of immunostaining before or after onset of eCG secretion in pregnant mares, but increased amounts of StAR were detected in corpora lutea from mares at day 40 or day 41 of pregnancy compared with non-pregnant mares and mares at days 20-30 of pregnancy.

Animals↗
PubMed1999

Universal primary colonic repair in the firearm era.

All patients with colonic trauma treated at King Edward VIII Hospital, Durban, from August 1993 to May 1994 underwent primary repair of the colonic wound. They were evaluated prospectively to assess the mode of injury and outcome variables. Colonic injuries were sustained by 102 patients. These were inflicted by gunshots (62), stabs (22), shotguns (14), and blunt trauma (4). The transverse colon was injured most frequently (53). All shotgun injuries were multiple. Average time from admission to theatre was similar for shocked and non-shocked patients. Eighty-seven patients had simple closure (18 deaths) and 15 required resection and anastomosis (eight deaths). Ten patients died in the first 48 h, and 16 died subsequently owing to multiple-organ systems dysfunction. The mortality rates were stabs 9% (2), gunshots 27% (17), shotguns 50% (7), and 0% for blunt trauma. Septic morbidity was seen in 16 but was not related to breakdown of the colonic repair. Implementation of strategies to reduce preoperative time delays and use damage control principles for the management of massive trauma should be evaluated as methods of reducing mortality.

Adolescent↗