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Biomedical subjects

R D Montgomery

Publications and source records attributed to R D Montgomery.

At least 19 recordsLinked to original sources
PubMed1992

Total hip arthroplasty for treatment of canine hip dysplasia.

Cemented THA is an established procedure for treating arthropathies of the hip in large, healthy mature dogs. CHD with secondary osteoarthritis is the most common indication. Although comparative studies between THA and excision arthroplasty have not been reported, our experience with both procedures and studies in the literature support THA as the best available treatment for crippling degenerative joint disease secondary to CHD in large, mature dogs. Negative aspects of the procedure include high cost, the potential of significant complications, and the sophisticated surgical technique required. Improvements in patient selection, design of implants, surgical technique, and postoperative care have decreased the incidence of complications and improved the success rate to over 90%. However, concerns in human applications about cement disease and the desire to increase the functional life of the prosthesis have renewed interest in cementless systems. Advantages of cementless THA are fixation via bony ingrowth and avoidance of problems associated with PMMA. Important technical aspects of cementless THA relate to optimal fit and fill so that the prosthesis is stable, bone ingrowth is promoted, and weight-bearing forces are transferred to the proximal femur physiologically. Problems recognized with cementless systems include fissure fracture, bone resorption, and excessive motion between the implant and bone. Currently, investigations are being conducted to develop prosthetic materials that more closely match the stiffness of bone, stem designs that provide optimal fit and maintain normal strain patterns in the bone, and coating materials that promote permanent fixation by bone ingrowth. Early clinical results in humans and research results in dogs have been encouraging but have not withstood the test of time. Results of cementless techniques must be compared to the standards set by cemented THA over the last 20 years in humans and the last 10 years in dogs.

Animals↗
PubMed1992

Small-bowel bacterial overgrowth in elderly people: clinical significance and response to treatment.

Duodenal-jejunal bacterial overgrowth is increasingly recognized in old age but its clinical significance is poorly defined. In this study, 16 elderly subjects were selected on the basis of an abnormal lactulose breath hydrogen test from a series of 27 in whom there was some reason to suspect malabsorption. In 12 of these 16 cases, pentagastrin tests showed normal gastric acid secretion and in 12 cases the small bowel was radiologically normal. Nutritional assessment, anthropometric measurements, culture of small-bowel aspirates, 14C-triolein breath tests and blood xylose tests were performed before and after 4 to 6 months of cyclical antibiotic therapy. Initially all patients except two showed evidence of malabsorption. After antibiotic treatment alone, 13 patients gained in weight and body fat. There were significant rises in the mean levels of haemoglobin, serum protein and calcium. Blood xylose test levels increased in 14 cases, reaching normal in all except one, whereas 14C-triolein excretion also increased in 14 and reached normal in 12 out of 16 cases. The breath hydrogen test reverted to normal in all cases and bacterial overgrowth was eliminated in 10 out of 11. The mouth-to-caecum transit time was prolonged initially (mean 190 min) and was unaffected by therapy (mean 196 min). Malabsorption and undernutrition are significant features of small-bowel overgrowth in the elderly and can be specifically corrected by antibiotic treatment. The clinical effect can be equally severe in elderly patients with or without an anatomical defect of the small bowel.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Accuracy of clinical isometry and preload testing during anterior cruciate ligament reconstruction.

To determine the effect of suture elongation on the accuracy of tension isometers, an anatomic specimen was used to measure peak loads on suture materials placed in extreme nonisometric positions. Accuracy and reproducibility were determined for three tension isometers, and the influence of suture elongation was determined for one of them. In one device, reproducible readings ranged from -12.3% to + 23.6% of mean static loads recorded by hydraulic testing equipment; average error approached 39.1%. Values tended to be overestimated if readings ranged as high as 32.5% over specific excursion ranges. Selected suture materials were subjected to these loads, using hydraulic testing equipment. Stainless steel exhibited extremely low levels of elongation but only at large diameters. Ethibond had similar low levels of elongation but only at large diameters. Monofilament nylon exhibited significant elongation that could cause erroneous readings and nonisometric placement. The measurement tolerances of a selected tension isometer should be considered by the surgeon performing anterior cruciate ligament (ACL) substitution. Several readings, both loading and unloading, can be used to determine preload and isometry. Material properties of the selected suture and the accuracy of the tension isometer should be considered when interpreting readings from isometric positioners. This brings into question the ability of currently available tension isometers to deliver readings within prescribed tolerances for either isometry of preload testing.

Anterior Cruciate Ligament↗
PubMed1991

Duodenal mucosal morphometry of elderly patients with small intestinal bacterial overgrowth: response to antibiotic treatment.

Microscopic changes in duodenal biopsy specimens from 16 elderly patients with small-bowel bacterial overgrowth were studied before and after cyclical courses of antibiotic treatment, using computer-aided morphometry measurements as well as visual assessment. Twenty-three subjects in the same age group with no evidence of intestinal disorder were studied as controls. Mean villus height was significantly reduced in the pre-treatment study compared to the post-treatment measurements and those in controls. Similar significant differences were found in mean crypt depth and total mucosal thickness. The mean intra-epithelial lymphocyte count was raised before treatment and fell after treatment to a level similar to that of the controls. The mean lymphocyte count in the peripheral blood rose significantly after treatment. This study provides objective evidence of microscopic structural changes in the bacterial overgrowth syndrome in old age. The return to normality after antibiotic treatment suggests that these changes are directly attributable to the presence of bacteria in the gut lumen.

Aged↗
PubMed1989

Healing of muscle, ligaments, and tendons.

The function of muscle, tendons, and ligaments is to transmit tensile forces. Healing by scar tissue compromises this function because scar tissue is weaker and more elastic than the tissue it replaces. First intention healing is promoted by suturing with strong, inelastic materials (eg, monofilament nylon, polyesters, etc) in a locking loop or three-loop pulley pattern to prevent gap formation, maintain vascularity, and decrease adhesions. Postoperative care should include restriction of active motion to avoid rerupture or gap formation across the suture line during tensile loading. However, immobilization for 6 weeks results in a wound with approximately 50% the normal tensile strength for tendons and ligaments and "significant weakening" of muscles. Earlier tension across a muscle, ligament, or tendon wound orients the healing fibers and results in stronger healing. For example, medial collateral ligaments of canine stifles sutured with polyester suture in a locking loop pattern and immobilized for 3 weeks, followed by active motion, resulted in valgus-varus laxity 1.5 times of controls and in strength, 92% that of controls. In comparison, 6 weeks of immobilization resulted in valgus-varus laxity three times that of controls and in strength, 14% that of controls. Canine tendons immobilized for 3 to 6 weeks after surgery also have sufficient strength to allow active motion. Current knowledge of healing muscle, tendons, and ligaments suggests that postoperative immobilization for 3 weeks will allow acceptable return to function while minimizing the risk of rerupture. However, the amount and type of exercise allowed immediately after immobilization devices are removed should be severely limited, and increased gradually as time passes.

Animals↗
PubMed1988

Comparison of over-the-top and tunnel techniques for anterior cruciate ligament replacement.

The osseous tunnel technique of anterior cruciate ligament (ACL) reconstruction was compared to the over-the-top (OTT) technique in vivo. A prosthesis replaced the ACL in 35 dogs by one of three methods: double osseous tunnels, OTT, or a combined method utilizing the unique Y shape of the prosthesis by placing one fork through a femoral osseous tunnel and the other fork over the top of the femoral condyle in the same stifle. Rupture occurred in all prostheses placed in double osseous tunnels and in one of 12 prostheses placed by the OTT technique. When rupture occurred in only one fork of prostheses placed in the combined method, all occurred in the tunnel-placed fork. If the results of the three groups are combined, rupture occurred in 16.7% of all OTT-placed prostheses versus 91.3% rupture of all osseous tunnel-placed prostheses. Objective assessment of the in vivo testing clearly indicates that the OTT technique is superior to the tunnel technique under the conditions of this study. The relationship between placement technique and rupture of other prostheses should also be tested in vivo.

Animals↗
PubMed1987

Ureterocolonic anastomosis in a dog with transitional cell carcinoma of the urinary bladder.

Ureterocolonic anastomosis and cystectomy were performed in a dog for treatment of transitional cell carcinoma of the urinary bladder. The dog remained an acceptable house pet for 10 months after surgery. However, the tumor recurred 10 months after surgery, and the dog was euthanatized. Our results indicated that the combination of ureterocolonic anastomosis and cystectomy can be an acceptable form of palliative treatment for transitional cell carcinoma of the urinary bladder in the dog.

Animals↗
PubMed1987

Congenital elbow dislocations.

Three categories of congenital elbow dislocations are described in the literature: humeroulnar, humeroradial, and dislocation or joint laxity with other congenital anomalies. Congenital humeroulnar dislocation is a well-defined problem that occurs predominantly in small breeds of dogs and causes severe limb deformity and dysfunction. Early reduction and stabilization are simple to achieve and have provided good results. Radial head dislocations occur most often as a result of growth disturbance of the radius and ulna. There is a lack of conclusive information on congenital radial head dislocations. Regardless of the etiology, radial head dislocation causes rather mild deformity and lameness and can be treated by conservative management, surgical correction, or radial head ostectomy. Dislocation of the elbow may occur concurrently with other rare congenital anomalies and has been described with ectrodactyly and polyarthrodysplasia.

Abnormalities, Multiple↗
PubMed1987

Ulcerative colitis in Asian immigrants.

Forty-four Asian immigrants in Birmingham and 44 age- and sex-matched white Caucasians with ulcerative colitis were compared to investigate the existence of any ethnic differences in the pattern of disease. Asian immigrants demonstrated a male preponderance of 2:1, and compared to the matched Caucasians there was a higher incidence of presenting eosinophilia and a milder course of disease, with more patients experiencing only a single initial attack. In spite of this clinical difference, total or subtotal colitis was the commonest pathological type in both white Caucasians and Indians, whereas in Pakistanis localized distal disease predominated. All ethnic groups suffered the same overall complication rate (55%) which is at variance with the experience of low complication rates in India. The age of onset of ulcerative colitis was related to age at immigration with a mean interval of 11 years. Although in some respects Asian immigrants share the disease pattern of the indigenous population, the observed significant differences could be of importance with regard to pathogenesis.

Adolescent↗
PubMed1986

Levamisole toxicosis in a dog.

A single oral dose of levamisole hydrochloride given at the rate of 12 mg/kg was believed responsible for bradycardia, tachypnea, hypothermia, cerebrocortical depression, and diarrhea in a dog. Supportive treatment and symptomatic treatment for the bradycardia were required for 4 days. In addition to these previously reported abnormalities associated with levamisole toxicosis, cerebrocortical depression and multiple foci of irritation were characterized by electroencephalography.

Animals↗
PubMed1986

Causes of malabsorption in the elderly.

The pathogenesis of malabsorption has been studied in 70 patients who presented over the age of 65 years and who were referred to a special investigative unit. Often more than one cause was apparent. Fourteen patients had pancreatic insufficiency, most of whom had no history of pain, alcoholism or gallstones. Twenty-three patients had the postgastrectomy syndrome or small-bowel diverticulosis or both. There were eight coeliacs aged 65-72 years at diagnosis. Fifteen patients had an anatomically normal small bowel; eight of these were over 80 years old, and 10 had vitamin B12 deficiency of whom five had confirmed pernicious anaemia. Enterobacterial overgrowth was a feature of all diagnostic groups except pancreatic and coeliac disease. Vitamin B12 deficiency may be an effect of malabsorption, but can also be a cause through impairment of enterocyte function. The association of pernicious anaemia and B12 deficiency with otherwise unexplained malabsorption and bacterial overgrowth suggests that gastric atrophy is a major causal factor in this syndrome, combined in some cases with a 'vicious circle' of B12 malabsorption and deficiency.

Aged↗
PubMed1986

Small bowel contamination and vitamin B12 deficiency in the elderly.

Bacterial contamination of the small bowel in the elderly can occur without any anatomical defect, but the importance and pathogenesis of this phenomenon are debatable. We describe two such patients, both with profound vitamin B12 deficiency. Clinical recovery took place without specific treatment of the bacterial overgrowth. In one patient with pernicious anemia, malabsorption of xylose and fat was corrected after vitamin B12 therapy. In the other gastric acidity was normal, but unsuspected mesenteric ischemia led to gangrene of the bowel. In old age there may be more than one explanation for vitamin B12 deficiency and for bacterial overgrowth. Vitamin B12 deficiency within the intestinal cells may be one common factor leading to malabsorption.

Aged↗
PubMed1985

Post-infective malabsorption in the temperate zone.

A series of 37 adults normally resident in Britain have been investigated for persistent bowel symptoms following acute enteritis. 26 had intestinal malabsorption, of whom 12 had been travelling in the Mediterranean area, whereas 10 developed their illness at home. Mild jejunal mucosal abnormalities were found in cases with and without malabsorption, and the intraepithelial lymphocyte count correlated more closely with the degree of malabsorption than did the histological grading. Over 80% of severe cases were folate deficient. Enterobacteria were cultured from the jejunal fluid in 30% of cases. Our observations confirm that post-infective malabsorption occurs sporadically in adults in the temperate zone and is occasionally severe. The condition involves small bowel contamination with enterobacteria, and it differs from acute tropical sprue only in its greater tendency to spontaneous recovery.

Adolescent↗
PubMed1984

Changing clinical pattern of gastric ulcer: are anti-inflammatory drugs involved?

The changing pattern of gastric ulcer (GU) has been studied in a series of 528 cases presenting in one hospital department during the past 20 years. The male:female ratio has declined and is now equal, and age-adjusted figures show that this applies to all age groups. There was a significant decline in mid-gastric ulcers in men. There was a 4-fold increased incidence of haemorrhage in proximal as opposed to antral ulcers and a 7-fold excess of haemorrhage in older women as opposed to younger women. GU in elderly women taking non-aspirin non-steroidal anti-inflammatory drugs (NANSADs) showed an increased tendency to bleeding, accounting for half of all haemorrhages in women over 70 years. However, on statistical analysis NANSAD-associated ulcers showed no other distinguishing features, and the use of NANSADs did not contribute significantly to the changing sex ratio. There is still no satisfactory evidence that these drugs play a causal role in chronic GU.

Adult↗
PubMed1982

Intestinal absorption in Saudi Arabia: an evaluation of the one hour blood xylose test.

The screening value of the one-hour blood xylose test, corrected for body surface area, was prospectively studied in Saudi Arabian adults and children under investigation for suspected intestinal malabsorption. Sensitivity of discrimination between patients with and without upper small bowel disease was 91%, compared to 85% for the five-hour urine xylose test. Primary small bowel disorder was rare. In a three-year review, no cases of adult coeliac disease or tropical sprue were found. The most common causes of malabsorption were intestinal tuberculosis, abdominal lymphoma and immunoproliferative small intestinal disease. Despite its acceptability as an index of proximal small bowel function, the blood xylose test alone is an inadequate screening test for any of these conditions.

Adolescent↗