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Biomedical subjects

S R Baker

Publications and source records attributed to S R Baker.

At least 73 records · Page 4Linked to original sources
PubMed1994

Epidemiology of chronic leg ulcers in Australia.

The aim of this study was to determine the point prevalence of ulceration of the leg in an Australian community. This was a population-based epidemiological study. Two hundred and fifty-nine patients with leg ulceration were identified by health care professionals of all types working in hospitals and private practices, as well as by self referral from patients. The base population in the study area was 238,000. The following data were recorded: age, sex, site of ulceration, duration of ulceration, history of previous ulceration and patient mobility. The point prevalence was 0.11%. The male:female ratio was 1:1.9; however the age related prevalence was similar for both sexes. The age related prevalence of ulceration was similar to that found in two similarly conducted studies in the United Kingdom. The ulcers were a chronic problem with 24% having been present for more than 1 year. Thirty-five per cent of patients had had a problem of ulceration for more than 5 years and 20% had suffered 10 or more episodes of ulceration. Related immobility was a prominent factor with 45% of patients being housebound. Chronic ulceration of the leg is a common recurrent problem in the elderly population and is likely to increase as the population grows. There is a definite need to improve the method of treating this problem.

Adult↗
PubMed1994

Reconstruction of midfacial defects following surgical management of skin cancer. The role of tissue expansion.

Compared with other locations on the face, skin cancer of the midface has a higher risk of recurrence owing, in part, to the mode of spread and the high frequency of subclinical extension. Skin cancers occurring in the region of the melolabial crease, nasal columella and medial canthus should be resected by Mohs surgery. Because tumors of the midface are sometimes recalcitrant, there are times when surgical ablation results in extensive defects. Reconstruction may be difficult owing to lack of available donor tissue, or because of previous surgery in the area of the proposed donor region. In these circumstances, tissue expansion in the form of controlled prolonged expansion or rapid intraoperative expansion, may, on occasion, provide the optimal reconstruction of form and function.

Aged↗
PubMed1994

Surgical variables affecting postoperative swallowing efficiency in oral cancer patients: a pilot study.

This study examined the correlation between swallow function at 3 months postoperatively and surgical variables including volume resected, flap volume, ratio of flap volume to volume resected, percentage of oral tongue, tongue base, and anterior and lateral floor of mouth resected, and whether or not the mandible was preserved in 30 surgically treated oral cancer patients. Swallows of measured amounts of liquid and paste (pudding) materials were examined videofluoroscopically. Nine measures of swallow function were completed for each swallow. A factor analysis of all swallow variables was done for liquid and for paste consistencies to determine whether one measure was statistically representative of all swallow measures. This analysis indicated that oral pharyngeal swallow efficiency (OPSE) represented all measures for both liquid and paste consistencies. Then the correlation between OPSE and surgical variables was defined. Only percentage of oral tongue and percentage of tongue base resected were significantly negatively correlated with OPSE. That is, OPSE decreased for both liquid and paste as percentage of oral tongue or percentage of tongue base resected increased. Results are discussed in terms of diet choices and surgical management.

Deglutition↗
PubMed1993

Assay of radiographic contrast agents in mice plasma and testes by high-performance liquid chromatography.

A new buffer system is reported for the analysis of radiographic contrast agents (RCAs) sodium meglumine diatrizoate, iohexol, and iopamidol in mice plasma and testes, on a reversed-phase HPLC with UV detection. The buffer consisting of 0.1 M NaH2PO4, 0.2 mM Na2EDTA adjusted to pH 3.1 with orthophosphoric acid and 2.5-5.0% acetonitrile (v/v) resolved RCA peaks for clear quantitation. The main advantages of this system are the ambient temperature of operation and direct sample injection without prior sample purification as required in the earlier procedures. Using this procedure, uptake and clearance kinetics of these RCAs were studied in mice plasma and testes, following iv injections via tail veins. The plasma levels of all the RCAs reached maxima between 5 and 15 min and dropped down sharply. At the end of 12 h they were virtually undetected (detection limits 0.64-0.71 micrograms/mL). The testicular levels also showed a similar trend and reached undetectable levels after 4 h. There were no signs of metabolism of these RCAs in plasma or testes. The present clearance kinetics in plasma compares very well with earlier reports of non-HPLC methods of assay.

Animals↗
PubMed1993

Comparison of venous reflux assessed by duplex scanning and descending phlebography in chronic venous disease.

Venous reflux was assessed by duplex scanning and descending phlebography in 98 limbs of 52 patients. There was moderately good agreement for deep vein reflux elicited by a standardised Valsalva manoeuvre, classified by a modified Kistner grading (0 to IV). The same grade was found in 58 limbs, with a difference of one grade in 27 limbs, and more than one grade in 13. Descending phlebography underestimated reflux in the lower leg compared with duplex scanning. The presence of reflux found on duplex scan correlated with the half-volume refilling time on a foot-volume plethysmogram with a below-knee tourniquet. There was no correlation between descending phlebography and the half-refilling time. Ascending phlebography showed post-thrombotic changes in 23 limbs. The duplex scan confirmed severe reflux (grades III and IV) in 14 of these 23 limbs, and demonstrated isolated reflux below normal valves in 4 other limbs. Severe reflux was seen on the descending phlebogram in only 10 of the 23 limbs with post-thrombotic changes. Duplex scanning may be a better method for detecting reflux than descending phlebography and is more acceptable to the patient. Ascending phlebography remains essential to display anatomical abnormalities found in some postthrombotic limbs that are not associated with reflux.

Adult↗
PubMed1993

Long-term results of treatment of peptic stricture of the oesophagus with the Angelchik prosthesis.

An Angelchik prosthesis was inserted in 43 patients with a peptic stricture above a hiatus hernia; 16 showed columnar lining of the oesophagus below the stricture. The mean preoperative bore of strictures was 8.7 mm. Within months, and without dilatation, 33 strictures shortened, 35 widened and of these 13 disappeared with a mean bore of 11.7 mm. In the long term, three more strictures resolved but three recurred. Final measurements gave a mean bore of 12.2 mm. The mean follow-up was 3.5 years. Symptomatic and radiological assessments suggested that the prosthesis was less effective when sited in the chest.

Abdomen↗
PubMed1993

Speech and swallowing function after anterior tongue and floor of mouth resection with distal flap reconstruction.

The purpose of this study was to assess the postoperative functioning of oral cancer patients with resections of the anterior tongue and floor of mouth, reconstructed with distal flap closure. Speech and swallowing performance was assessed for 11 men and 5 women preoperatively and at 1 and 3 months postoperatively following a standardized protocol. Speech tasks included an audio recording of a brief conversation and of a standard articulation test; swallowing function was examined using videofluoroscopy. Data were also collected on the number and duration of speech/swallowing treatment sessions, as well as the amount and duration of radiation therapy. Statistical analyses revealed that patients demonstrated a significant and severe impairment in speech and swallow functioning after surgery, with no recovery of function by 3 months post-healing. The degree of impairment in these patients may be related to the adynamic character of the distal flap used for reconstruction. Lack of improvement at the 3-month evaluation may be related to either the timing of postoperative radiation therapy or the low rate (44%) and amount of speech/swallowing treatment provided to these patients.

Adult↗
PubMed1993

Effects of diatrizoate and iopamidol on spermatogenesis.

RATIONALE AND OBJECTIVES: The biological effects of iodinated contrast media were examined by using spermatogenesis in mouse testis as the experimental model. METHODS: Spermhead survival and abnormality assays were used as the biological end points. Diatrizoate meglumine/diatrizoate sodium and iopamidol were administered intravenously at equal rates and concentrations. Testicular uptake and clearance of these contrast agents were examined by high-performance liquid chromatography techniques. Appropriate mannitol solutions were employed as osmolality controls. RESULTS: Intravenous administration of the contrast agent or its respective mannitol control resulted in approximately a 30% decrease in spermhead count. A dose-related experiment with mannitol demonstrated that the spermhead count decreased rapidly until 600 mOsm/kg was reached, beyond which this decrease was minimal. Clearance of both contrast media was complete in approximately 4 hours. No significant increase in the induction of spermhead abnormalities was observed. CONCLUSION: Osmotic substances, such as iodinated contrast agents, affect the process of spermatogenesis.

Animals↗
PubMed1993

The abdominal plain film. What will be its role in the future?

Conventional imaging studies are now being closely scrutinized for clinical utility. Some, like the skull film, are obsolete while others have secured an enduring place for themselves. The plain film of the abdomen occupies a middle ground with its role supplanted by other studies for many conditions but its value is still appreciated for the assessment of intestinal obstruction and perforation. Today, its special capabilities for the evaluation in diverticulitis and iron therapy have been under emphasized. In the future, the plain film will have a narrower focus but when combined with CT both examinations can be enhanced.

Barium Sulfate↗
PubMed1993

Venous ulceration in males with sex chromosome abnormalities.

Two patients with Klinefelter's syndrome and three with 47,XYY who had venous ulcers, and one patient with 47,XYY and a post thrombotic limb are described. Sex chromosome abnormalities should be suspected in tall males with leg ulcers, especially those who have no progeny and are relatively young. Venous ulcers may be more common in males with 47,XYY.

Adult↗
PubMed1992

Serial studies of autologous antibody reactivity to squamous cell carcinoma of the head and neck.

In previous studies we evaluated the incidence and specificity of autologous antibody reactivity against squamous cell carcinoma of the head and neck (SCCHN). We were able to demonstrate that autologous antibody reactivity is present in native sera but was usually of too low a titer to allow further analysis. Dissociation of immune complexes by acidification and ultrafiltration of serum augmented autologous antibody reactivity in nine out of nine autologous systems tested. Native antibody and antibody derived from immune complexes produced by the host and reactive with autologous tumor cells may be directed against physiologically relevant antigens. Therefore, correlations of antibody titers with clinical course may provide insight into the nature of the host response to cancer. In the present analysis, serological studies of six patients with SCCHN were performed with serum samples obtained over many months. Results of serial serological assays were correlated to tumor progression and clinical course. Fluctuations in autologous antibody reactivity were noted over time. In four cases, rises in autologous antibody titers preceded the clinical diagnosis of recurrence by several months. Drops in autologous antibody reactivity were noted in two cases following surgery or radiation therapy. In two cases of long-term survivors, no correlation between antibody reactivity and clinical course was noted. Specificity analysis of the six autologous systems demonstrated reactivity against autologous and allogeneic SCCHN as well as melanoma cell lines. These sera did not react with glioma, neuroblastoma, renal cell, breast, bladder and colon carcinoma cell lines nor with fetal calf serum, pooled lymphocytes, red blood cells and platelets. Autologous serial serological studies may provide a means by which to evaluate the host/tumor relationship in patients with SCCHN.

Aged↗
PubMed1992

Aetiology of chronic leg ulcers.

This study was undertaken to determine the relative prevalence of the factors causing chronic ulceration of the leg in the general population. Two hundred and fifty-nine patients with chronic ulceration of the leg were found on screening a Western Australian population of 238,000. (The prevalence of chronic ulceration of the leg was 1.1 per 1000 population.) Two hundred and forty-two of these patients (93%) with 286 chronically ulcerated limbs were fully assessed to determine the factors contributing to ulceration. In 239 limbs (84%) ulceration involved the leg; in these limbs venous disease was the most prevalent cause of ulceration (160 limbs). Arterial disease was found in 66 limbs, with both venous and arterial disease present in 35 limbs. Rheumatoid arthritis was a causative factor in 27 limbs and diabetes was found with 29 limbs with ulceration involving the leg. In 47 limbs (16%) ulceration was confined to the foot; arterial disease (35 limbs) and diabetes (23 limbs) were the most prevalent causes of ulceration in these limbs. Venous disease was infrequent (three limbs). No disorder of the circulation was found in 48 limbs (20%) with ulceration involving the leg, and in 58 (20%) of all ulcerated limbs. More than one aetiological factor was present in 93 limbs (33%). A cause for ulceration was not found in 10 limbs (3.5%).

Adult↗
PubMed1991

In vitro radiation resistance among cell lines established from patients with squamous cell carcinoma of the head and neck.

Twenty-five squamous cell carcinoma (SCC) cell lines from 20 patients with head and neck cancer were assessed for radiosensitivity in vitro using a 96-well plate assay. Four non-SCC lines were also tested. Radiation sensitivity of individual cell lines was compared using the area under the survival curve (AUC) as a measure of the mean inactivation dose. Tumor lines were tested with either a cobalt-60 (60Co) gamma-irradiator having a dose rate of 100 cGy/minute or with a 4-meV photon beam having a dose rate of 200 cGy/minute. The mean AUC of the 25 SCC cell lines was 188 +/- 7 (SEM) cGy (range, 100 to 250 cGy) whereas the four non-SCC lines had a mean AUC of 225 +/- 9 cGy. The SCC cell lines with mean inactivation dose values greater than 188 cGy were classified as relatively radioresistant whereas those with values less than 188 cGy were considered relatively radiosensitive. In seven cases SCC cell lines were derived from patients who had already received radiation therapy. In four of these cases the tumor cell lines were radioresistant (AUC, 210 to 250) but in the other three cases the tumor lines were radiosensitive (AUC, 160 to 180). Thus, failure of a tumor to respond to radiation did not always select for radioresistant cells. The mean of the AUC for cell lines from previously irradiated patients (197 +/- 11 cGy) did not differ significantly from that of the cell lines from patients who received no prior radiation therapy (182 +/- 9 cGy). However, among radiation-resistant lines those from the four previously irradiated patients were significantly more resistant (mean AUC = 235 +/- 9) than seven other radioresistant lines from nonirradiated patients (mean AUC, 208 +/- 4) (P = 0.0194). In four cases more than one cell line was derived from different tumor specimens in the same patient. In each of these cases the lines from the same patients were similar to one another in their degree of radioresistance. Based on these observations the authors conclude that the degree of in vitro radiation resistance is an inherent property of some squamous cell tumors.

Adult↗