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Biomedical subjects

R McLaughlin

Publications and source records attributed to R McLaughlin.

At least 55 records · Page 3Linked to original sources
PubMed1991

Surgical management of collapsed pelvis in a jaguar.

An immature jaguar was surgically treated for severe constipation caused by a narrow pelvic canal. This narrowing was attributed to nutritional secondary hyperparathyroidism. The ventral floor of the pelvis was widened by placing a piece of high density polyethylene between the 2 sides of the pubis after symphysiotomy and stabilizing the implant with orthopedic wires. This procedure provided stable fixation and permanent enlargement of the pelvic canal. The technique was easy to perform and could be used to treat pelvic collapse in other species.

Animals↗
PubMed1990

Effects of phenobarbital, dietary protein intake, and ewe liveweight on ovulation rate and concentrations of plasma FSH and hepatic microsomal enzymes.

Coopworth ewes were differentially fed from December 1985 to April 1986 to produce two liveweight classes: fat (55-60 kg) and thin (40-45 kg). The ewes were then fed on either high-protein (22%) or low-protein (12%) diets, with or without phenobarbital treatment for 10 days commencing on Day 7 of the oestrous cycle. Phenobarbital treatment caused an increase in ovulation rate that was most pronounced in thin ewes and those on the low-protein diet. Ewe liveweight produced an increase in ovulation rate, but increased dietary protein in the particular formulations used had no effect. Hepatic enzyme concentrations were increased by phenobarbital treatment and, to a lesser extent, by dietary protein intake and ewe liveweight. However, these metabolic changes and the increase in ovulation rate were not accompanied by interpretable changes in the plasma FSH concentrations.

Analysis of Variance↗
PubMed1990

Corneal endothelial response to refitting polymethyl methacrylate wearers with rigid gas-permeable lenses.

Thirteen persons who had been wearing only polymethyl methacrylate (PMMA) contact lenses for 3 years or more were switched to a contact lens material providing greater oxygen transmissibility (Itafocon A) while keeping other contact lens parameters the same. Monitoring of corneal endothelial cells during the first 4 months of the rigid gas-permeable (RGP) lens daily wear showed no significant change in the coefficient of variation of cell area (polymegethism) or percentage of hexagonal endothelial cells at the end of 4 months. However, paired data did show a small, but significant, decrease in cell density at the end of 4 months (3174 to 2908 cells/mm2). The results suggest that a sudden shift in the general corneal environment toward more available oxygen may have some early effect on endothelial cell density, but changes in endothelial cell size variation and form are not determined.

Adult↗
PubMed1989

Mucoepidermoid carcinoma of the parotid as a second malignant neoplasm in children.

Second malignant neoplasms (SMN) in children who have survived their initial encounter with a malignancy have emerged as one of the most troublesome complications in pediatric oncology. Some estimates indicate that as many as 8% to 12% of patients will develop a SMN during a 20-year period. The majority of SMN are osteosarcomas, spindle cell and pleomorphic sarcomas of soft tissues, and hematolymphoid malignancies. We present the clinical and pathologic findings for two children with treated acute leukemias in whom well-differentiated mucoepidermoid carcinomas of the parotid gland developed 6 and 9 years after multidrug chemotherapy and cranial irradiation. Although mucoepidermoid carcinoma has been reported as a complication in adults who received low-dose irradiation as children, these two cases are unique as SMN in the pediatric age population.

Carcinoma↗
PubMed1987

The flexibility and topology of simian virus 40 DNA in minichromosomes.

The linking number of DNA in minichromosomes increases by 2 turns during SV40 assembly. Changes in temperature also influence the average linking number of the total intracellular forms of SV40 DNA. When the isolated minichromosomes assembled in vivo are incubated with topoisomerase I at 33 degrees C in vitro, the linking number of SV40 DNA decreases. This decrease is about: -1.1 turns for minichromosomes with an average nucleosome spacing of 198 base pairs (bp), wt776; and -0.6 turns for minichromosomes containing a shorter average nucleosome repeat (177 bp), tsC219. The difference between the average linking number of naked SV40 DNA relaxed with topoI at 33 degrees C and minichromosomes relaxed with the enzyme at the same temperature indicates that SV40 chromatin contains on the average 26 nucleosomes. However, the results of studies obtained both on DNA flexibility in chromatin and in naked DNA, and on the shape of the topoisomer distribution curves, indicate that all of the minichromosomes, regardless of their overall structure, do not contain the same number of nucleosomes; this heterogeneity may be as large as 8 nucleosomes. We find no apparent correlation between the amount of minichromosomes containing unconstrained torsional stress and the abundance of the molecules with a structure characteristic of transcriptionally active chromatin.

Chromatin↗
PubMedDate not supplied

Are elevated levels of the tumour marker CA19-9 of any clinical significance?--an evaluation.

CA 19-9 is a tumour marker which has been used widely in patients with pancreatic adenocarcinoma. Elevated levels are associated with advanced disease at presentation and disease progression during follow-up. CA19-9 levels may also be elevated in a variety of other malignant and benign conditions. This study examined the significance and implications of elevated CA19-9 levels. An analysis of all CA19-9 measurements performed over a 4 yr period was undertaken and 204 patients with elevated CA19-9 levels were identified. One hundred and thirty patients (63.7 per cent) had malignant conditions and 74 (36.3 per cent) had benign conditions or no definite cause was found. There was a significant correlation between CA19-9 levels and CEA (r = 0.3137; P < 0.001) as well as alkaline phosphatase, ALT, AST, bilirubin, gamma glutamyl transpeptidase and lactate dehydrogenase. CA19-9 levels were significantly lower in patients with benign pathology than those with malignant pathology. Similar differences were observed for CEA. CA19-9 levels were in fact highest in patients with pancreatic carcinoma (P < 0.05) while no significant differences were observed for CEA. In conclusion CA19-9 may be elevated in both benign as well as malignant conditions and interpretation of CA19-9 results must be made in light of the clinical condition of the patient.

Adenocarcinoma↗
PubMedDate not supplied

Prognostic implications of p53 and bcl-2 expression in 108 women with stage two breast cancer.

BACKGROUND: The mortality and morbidity of patients with breast cancer can vary even between individuals with similar histological stage at diagnosis. Identification of those individuals with prognostically poorer tumours is an essential prerequisite in planning adjuvant therapies. Some prognostic indices of tumour size, grade, oestrogen receptor status and nodal status are well established. AIM: The aim of this study was to examine the prognostic role of information relating to proto-oncogene and tumour suppressor gene expression. METHODS: 108 women with stage II breast cancer were studied. Tumour expression of p53 and bcl-2 were scored and then correlated with recurrence and mortality. RESULTS: We have shown that individuals poorly expressing bcl-2 in their tumours have a poorer disease-free and overall survival than those who express bcl-2. When p53 was strongly expressed, it was associated with poorer disease-free and overall survival. CONCLUSION: The profiling of individual tumour genetic expression of proto-oncogenes may allow for more specific identification of patients at higher risk of recurrence in breast cancer.

Biomarkers, Tumor↗
PubMedDate not supplied

The role of apoptotic cell death in cardiovascular disease.

BACKGROUND: Programmed cell death, or apoptosis, is a distinct, managed form of cell death. It is fundamentally different from necrosis. It is a genetically controlled, energy-dependent method of cellular deletion without inflammation. In the cardiovascular system, apoptosis occurs as a primary and secondary event in disease pathogenesis. This review addresses our current understanding of the initiation, propagation and significance of apoptosis in the cardiovascular system, as well as assessing therapeutic potentials arising therefrom. METHODS: A Medline search was performed and relevant publications reviewed. Further articles were obtained from the references of these publications. RESULTS: and conclusions Apoptotic cell death is a key element in the pathogenesis and progression of ischaemia-reperfusion (IR) injury, cardiac failure, myocardial infarction, atherosclerosis, endothelial dysfunction and the clinical syndromes which these situations produce. Our increased understanding of the role of apoptosis in the pathogenesis of cardiovascular disease offers potential to develop new therapeutic strategies.

Apoptosis↗
PubMedDate not supplied

Urinary incontinence after surgical repair of ureteral ectopia in dogs.

Eleven of 20 dogs (55%) were incontinent after surgical treatment of ureteral ectopia. Ureterocystostomy was performed in 15 dogs, ureteral transection and bladder reimplantation in four dogs, and ureteronephrectomy in one dog. Siberian huskies had a significantly higher rate of persistent postoperative incontinence than other breeds. There was no difference in postoperative incontinence between dogs with unilateral and bilateral ectopia. Concurrent bacterial cystitis was not associated with persistent postoperative incontinence. Age at the time of surgical correction had no effect on the rate of postoperative incontinence. Eight incontinent dogs were treated medically; three are continent with medication, three are improved but still incontinent, and two did not improve.

Animals↗
PubMedDate not supplied

A comparison of two surgical approaches to the scapulohumeral joint in dogs.

Two scapulohumeral arthrotomy techniques were evaluated and compared in 10 normal, young adult greyhounds. A caudolateral approach with craniodorsal retraction of the teres minor muscle (no-tenotomy) and a craniolateral approach with tenotomy of the infraspinatus tendon were each performed unilaterally in 5 dogs. The dogs were evaluated using force plate gait analysis, lameness evaluation, radiography, and goniometry for 5 weeks and then euthanatized. Tenotomy sites and sections of the humeral articular cartilage were collected from shoulder joints that had been operated on and examined microscopically. The same surgical approach has then performed on the contralateral shoulder in the cadavers and exposure of the humeral articular cartilage was measured using planimetry. Peak vertical force applied to the operated limbs in the tenotomy group was significantly less than preoperative leads on day 3 and significantly less than the no-tenotomy group on days 21 and 28. The peak vertical force applied to the operated limbs in the no-tenotomy group was not significantly different from preoperative levels during the study. Scapulohumeral arthrotomy by tenotomy of the infraspinatus resulted in decreased range-of-motion and joint extension compared with joints operated on without tenotomies, but provided significantly greater exposure to the articular surface. Scapulohumeral arthrotomy with craniodorsal retraction of the teres minor muscle did not significantly alter goniometric measurements compared with unoperated joints. Both techniques resulted in similar subjective lameness scores and caused no gross microscopic or radiographic evidence of articular cartilage damage.

Animals↗
PubMedDate not supplied

Development of interactive patient-based multimedia computer programs in veterinary orthopedic radiology.

Three computerized multimedia programs on large and small animal veterinary orthopedic radiology were developed and implemented for the radiology curriculum as an alternative to traditional film-based laboratory learning. Programs utilized "hot words" (colored text words that displayed an overlaid image label that highlighted lesions) and interactive quizzes which responded appropriately to selected answers. "Hot words" helped students develop confidence in accurate lesion detection and the interactive quizzes transformed learning from a passive to an active process. Multiple examples were provided for reinforcement and concepts were incorporated from other clinical disciplines for curriculum integration. Programs were written using a presentation software program, Toolbook for DOS based platform, and contained radiographic images made by laser-scanning digitization. Multiple students could simultaneously access the programs through a network server. These pilot programs were implemented successfully and computerized multimedia presentation proved to be well suited to teaching radiology. Development of the programs required attention to a number of hardware, software, time and cost factors.

Computer Communication Networks↗