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Biomedical subjects

S R Smith

Publications and source records attributed to S R Smith.

At least 235 records · Page 13Linked to original sources
PubMed1991

Retrocolic pelvic omentoplasty in abdominoperineal excision of the rectum.

A series of 53 patients underwent abdominoperineal excision of the rectum, 25 by the conventional method and 28 using retrocolic pelvic omentoplasty without drains. There were no differences in age, sex ratios, indications for surgery, stage of cancer and preoperative haemoglobin. There were no differences in the incidence of postoperative abdominal complications (wound dehiscence, obstruction and bleeding) between the two groups. However, patients undergoing omentoplasty without drainage stayed in hospital for a significantly shorter period (median of 16 days compared to 24 days) and benefited from far faster primary healing of the perineum (median of 20 days vs 133 days). It is concluded that retrocolic pelvic omentoplasty without drainage results in shortened postoperative hospital stay and promotes primary perineal healing after abdominoperineal excision of the rectum.

Abdomen↗
PubMed1990

Flow cytometric analysis of recombinant murine GM-CSF (rmuGM-CSF) induced changes in the distribution of specific cell populations in vivo.

The changes in the distribution of granulocytes, monocytes, and lymphocytes in various tissue compartments following subcutaneous (SC) administration of recombinant murine GM-CSF (rmuGM-CSF) in vivo was determined by flow cytometry in time course studies. Balb/c mice were given single, daily SC injections of 1 or 4 micrograms of rmuGM-CSF for 10 days. Flow cytometric analysis was performed on bone marrow (BMC), peritoneal exudate (PEC), and peripheral blood (PBC) cell preparations from mice treated for 1, 3, and 10 days. Dual fluorescence was employed to gate on leukocytes (T200+) and analyze for Ig+, Thy 1.2+, MAC+, and 8C5+ (granulocytes) cells. The analyses indicated that SC-rmuGM-CSF increased the percentage of 8C5+ cells in PBC after 1 day of treatment. However, significant changes in the cell composition of PEC and BMC were not observed until day 10 of treatment and included increases in 8C5+ cells and the myeloid cell population, respectively. Side scatter analysis (cell density) of PBC and PEC indicated that the percentage of the granulocytic cell population increased significantly in rmuGM-CSF treated mice. The changes observed in PEC and BMC appeared to be dose-related whereas those observed in PBC were not. These data clearly demonstrate the utility of flow cytometric analyses for detecting selective effects of cytokines on cell populations that are involved in host defense mechanisms.

Animals↗
PubMed1990

Effect of fracture fixation on cortical bone blood flow.

Because internal and external fixation devices alter blood flow, and thus the transport of nutrients to the cortical bone of a healing fracture, we studied the effects of a fluted intramedullary rod (IMR), a half-frame external fixator (EF), and a compression plate (PL) on the cortical bone directly adjacent to the fracture site at 4 and 48 h and 14 and 90 days after fixation. Three specific areas of cortical bone were studied: endosteal cortex, periosteal cortex, and subplate cortex (cortical bone under the compression plate). The fractures fixed with IMR had the lowest blood flow at all time periods studied. At 4 h, the difference between IMR and PL or EF was statistically significant in the endosteal cortex (p less than 0.01 or p less than 0.05, respectively); also, the difference between the IMR and EF in the subplate cortical bone region was significant (p less than 0.05). At 14 days, the blood flow to the endosteal cortex was still significantly lower with IMR than with EF (p less than 0.025). At 90 days, the blood flow to the subplate region of cortical bone was significantly (p less than 0.02) higher with PL than with IMR but there was no significant difference in bone remodeling with the different fixation devices.

Animals↗
PubMed1990

Inhibition of collagen II-induced arthritis in mice--a comparison of the effects of Sch 24937, immunosuppressants and nonsteroidal antiinflammatory drugs on the clinical expression of disease.

Previous studies from this laboratory have described Sch 24937 as a potent immunosuppressive agent that is particularly effective in suppressing humoral immune responses in mice. These findings prompted an evaluation of the effects of Sch 24937 in type II collagen-induced arthritis in mice where disease manifestations include the development of a strong humoral response to the collagen antigen. Sch 24937 reduced the incidence and severity of arthritis in collagen sensitized mice which appeared to be directly related to the immunosuppressive properties of the drug. However in contrast to the steroid betamethasone which also exhibited immunosuppressive activity, Sch 24937 did not prevent the changes occurring in the lymphocyte population of the draining lymph nodes of mice immunized with type II collagen. While the exact mechanism of the immunosuppressive activity of Sch 24937 remains to be elucidated, its mode of action in suppressing arthritis differs at least to some extent from that of a steroid.

Animals↗
PubMed1990

The assessment of treatment response in non-Hodgkin's lymphoma by image guided 31P magnetic resonance spectroscopy.

Serial image guided 31P magnetic resonance spectroscopy (MRS) studies were performed in eight patients with non-Hodgkin's lymphoma to determine the changes in phosphorus metabolites that occur in vivo in response to chemotherapy. Pre-treatment spectral characteristics were different in high and low grade lymphoma. A larger inorganic phosphate (Pi) peak was seen in high grade NHL relative to phosphomonoesters (PME) or beta adenosine triphosphate (beta ATP), producing significant differences in the PME/Pi and Pi/beta ATP metabolite ratios, and probably reflecting a larger hypoxic cell fraction within the high grade lymphomas. Consistent metabolite changes were seen with treatment, and before reductions in tumour bulk had occurred. Alterations in tumour energetics with changes in Pi and beta ATP, and increases in phospholipid turnover reflected as an increase in the phosphodiester (PDE) resonance were detected. Changes were seen between days 10 and 27 in low grade lymphoma treated with oral alkylating therapy and between days 1 and 5 in lymphoma treated with intensive combination chemotherapy. Increases in the PDE/beta ATP metabolite ratio may be an early indicator of response to chemotherapy in human tumours. These studies illustrate the feasibility and clinical potential of image guided 31P MRS as a means of assessing response to therapy.

Adenosine Triphosphate↗
PubMed1990

An assessment of the clinical skills of fourth-year students at four New England medical schools.

This paper describes a collaborative effort among five New England medical schools to assess important clinical skills of fourth-year medical students graduating in the class of 1988; results are presented from the four schools that provided sufficient data. Faculty from each school developed 36 patient cases representing a variety of common ambulatory-care problems. Over the course of a day, each student, on average, interacted with 16 different standardized patients, who were nonphysicians trained to accurately and consistently portray a patient in a simulated clinical setting. The students obtained focused histories, performed relevant physical examinations, and provided the patients with education and counseling. At each school, the performance of a small number of the students fell below standards set by the faculty. These deficiencies were not detected with the evaluation strategies currently being used. Although the use of standardized patients should not substitute for the process of faculty observing students as they interact with real patients, it appears that standardized patients can provide faculty with important information, not readily available from other sources, about students' performances of essential clinical activities and the levels of their clinical skills.

Ambulatory Care↗
PubMed1990

Role of glycopeptide antibiotics in the treatment of febrile neutropenic patients.

The exact timing of the introduction of the glycopeptide antibiotics teicoplanin and vancomycin in the management of the febrile neutropenic patient continues to be controversial. However, there are certain firm criteria now emerging. Bacteraemia can be eradicated with a success rate approaching 100% in cases where the organism can be identified and shown to be sensitive. Approximately 65% of cases of soft-tissue infection, usually occurring with the use of a Hickman or equivalent indwelling catheter, are associated with the presence on culture of Gram-positive organisms of presumed skin origin. Such infection is an indication for the early use of antibiotics with proven activity against coagulase-negative staphylococci and diptheroids. Resolution of fever in up to 50% of cases may result from using 'planned progressive therapy': the introduction of specific Gram-positive cover in patients who have failed to respond at 48-72 h to regimens such as a ureidopenicillin or a third-generation cephalosporin with or without an aminoglycoside. This approach reduces the number of patients who go on to receive empirical amphotericin B intravenously for presumed fungal infection. Using teicoplanin or vancomycin as first-line agents in the empirical treatment of first fever in febrile neutropenic patients is perhaps more controversial. Recent developments which include using quinolone-based prophylaxis more widely and introducing cytokines to reduce the period of neutropenia may increase the likelihood that a neutropenic patient's febrile episode will be due to a Gram-positive organism. The dilemma of choosing broad-spectrum monotherapy or targeted combination therapy in the situation remains unresolved. Current studies, however, should help to clarify this situation. Finally, other current studies of teicoplanin and vancomycin as prophylactic agents administered either orally or systemically, may provide additional indications for their use in the neutropenic patient.

Aminoglycosides↗
PubMed1989

The use of a caries detector dye in cavity preparation.

The aim of this study was to compare the conventional visual and tactile method of detecting carious dentine during cavity preparation using a mirror, probe and excavator with a visual method enhanced by a dye. The dye, 1% acid red in propylene glycol, was used on 100 cavities prepared by dental students and passed as clinically satisfactory by their teachers. Results showed dye stain at the enamel-dentine junction in 57 cavities (57%) which had been assessed as caries-free in this area using conventional visual and tactile means. Subsequent laboratory work on extracted carious teeth confirmed histologically that the dye stains demineralised dentine. If clinicians consider it important to render the enamel-dentine junction caries-free, it might be prudent to use the dye as an aid to diagnosis in this area.

Coloring Agents↗
PubMed1989

Role of venous elasticity in the development of varicose veins.

A reduction in the 'elasticity' of the venous system has been proposed as a precursor of venous insufficiency, but the concept remains controversial. This study was designed to develop a method of assessing venous elasticity, and to use this method to investigate the aetiology of varicose veins. Simultaneous measurements of calf volume (determined using strain gauge plethysmography) and venous pressure (obtained via a dorsal foot vein) were made during venous occlusion plethysmography. The elastic modulus, K, defined as stress/strain when the veins are full, was calculated from the pressure/volume relationship. The elastic modulus was determined in 19 normal legs, 33 legs with superficial venous insufficiency, 16 legs with deep venous insufficiency, and 18 legs of a high risk group of volunteers or patients without varicose veins but with a strong history of factors associated with their development. The results showed a clear difference in elasticity between normal limbs and limbs with varicose veins, and also between normal limbs and high risk limbs. These results support the hypothesis that reduced elasticity has a role in the development of varicose veins and precedes the onset of valvular incompetence.

Elasticity↗
PubMed1989

Image localized 31P magnetic resonance spectroscopy of the human liver.

Image localized 31P magnetic resonance (MR) spectroscopy of the liver was performed in twelve normal volunteers and seven patients with hepatic tumours. The tumours which were clearly imaged by proton MR could also be distinguished from normal tissue because of spectral differences. The malignant tumours had significantly elevated phosphomonoester/inorganic phosphate and phosphomonoester/beta-adenosine triphosphate ratios, probably due to elevated tumour concentrations of phosphocholine and phosphoethanolamine, which are intermediates in the synthesis of membrane phospholipids. The pH values of the malignant tumours were elevated compared to normal hepatic parenchyma. Liver spectra in two patients with the commonest benign hepatic neoplasm, cavernous haemangioma, differed from both normal tissue and the malignant tumours in having a very low signal/noise ratio but apparently normal relative levels of phosphomonoester.

Adult↗
PubMed1989

Characterization of the spleen by in vivo image guided 31P magnetic resonance spectroscopy.

Image localized 31P magnetic resonance spectroscopy of the spleen was performed in six normal volunteers, 13 patients with splenomegaly due to haematological malignancies, and two patients with benign causes of splenomegaly. The malignant disorders had elevated phosphomonoesters (PME) compared to controls, probably due to increased turnover of membrane phospholipids, with variable alterations in high energy phosphates. There appeared to be no relationship between grade of malignancy and relative PME peak area. An overlap in spectral characteristics between the benign and malignant cases of splenomegaly existed. Serial studies in a patient with high grade lymphoma receiving combination chemotherapy showed changes in phosphorus spectra, with an increase in the phosphodiester/beta adenosine triphosphate ratio.

Adult↗
PubMed1989

Comparative study of functional bracing and plaster cast treatment of stable lateral malleolar fractures.

In a prospective, randomized study, the use of the Aircast pneumatic air stirrup was compared with a standard below-knee walking cast in the management of Lauge-Hansen supination-eversion, stage II ankle fractures. Forty patients were randomly allocated to the two treatment groups. The use of the air stirrup led to a significant improvement in early patient comfort, post-fracture swelling, range of ankle motion at union, and time to full rehabilitation. We advocate the use of pneumatic air stirrup in the cost-effective management of stable ankle fractures.

Ankle Injuries↗
PubMed1989

Quantitative and subjective analysis of temporomandibular joint radiographs.

The lateral oblique transcranial radiograph of the temporomandibular joint is commonly used in dentistry. Changes in horizontal angulation of the x-ray beam can produce changes in radiographic condylar position. This study used quantitative and subjective methods to assess and rank changes in radiographic condylar position as a function of known horizontal x-ray beam changes. Six dry skulls were positioned in a craniostat device where known angulations could be measured. Nine sequential transcranial temporomandibular joint radiographs were made of each joint and five of these 12 sets were randomly selected for analyses. The quantitative method involved film digitization, computer calculations, and expressed condylar position as a ratio between posterior and anterior joint space distributions. Eight observers viewed the same films and ranked radiographic condylar position from anterior to posterior. The two methods agreed with known rankings 81.8% of the time. Subjective rankings were more variable than quantitative rankings. Intraobserver differences were insignificant and the observers were consistent among themselves as a group.

Cephalometry↗