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Biomedical subjects

I Reid

Publications and source records attributed to I Reid.

At least 19 recordsLinked to original sources
PubMed2000

Pectinase in papermaking: solving retention problems in mechanical pulps bleached with hydrogen peroxide.

Treatment with the enzyme pectinase has been reported to lower the cationic demand of thermomechanical pulp (TMP) bleached with alkaline peroxide in the laboratory. We have extended this discovery to bleached TMP produced industrially, and shown that commercial enzyme preparations can treat pulp within 15 min at the temperature and pH values prevalent in paper mills. About half of the cationic demand in the bleached pulp can be destroyed by pectinase. Dynamic drainage jar experiments show that the enzyme treatment improves the effectiveness of several cationic polymers to increase retention of fines and filler particles. It does not increase retention in the absence of retention aids or with nonionic polymers, and does not damage the strength properties of the pulp. Pectinase could be easily incorporated into paper machine stock preparation systems to lower the charges of cationic retention aids needed in furnishes containing peroxide-bleached mechanical pulp.

Journal Article↗
PubMed1997

Tranexamic acid reduces blood loss and transfusion in reoperative cardiac surgery.

PURPOSE: The objective of this study was to assess the effect of tranexamic acid (TA), a synthetic antifibrinolytic, on blood loss and the need for transfusion of blood products following repeat cardiac valve surgery. METHODS: After ethics committee approval, 41 patients scheduled for reoperative valve replacement were enrolled in this randomized, double blind, placebo controlled study. Patients were randomized to receive TA (10 g in 500 ml NSaline) or placebo (NSaline) as an iv bolus over 30 min, after anaesthesia induction and prior to skin incision. Intraoperative blood loss was assessed by estimating blood volume on drapes, weighing surgical sponges, and measuring suction bottle returns. Postoperative blood loss was measured from mediastinal chest tube drainage following surgery. Blood products were transfused according to a standardized protocol. RESULTS: Patient demographics were similar for age, sex, cardiopulmonary bypass pump time, cross clamp time, surgical time, preoperative haemoglobin, coagulation profile, and the number of valves replaced during surgery. Tranexamic acid administration reduced intraoperative blood loss [median (range)] from 1656 (575-6270) to 720 ml (355-5616) (P < 0.01) and postoperative blood loss from 1170 (180-4025) to 538 ml (135-1465) (Intent to Treat n = 41, P < 0.01). The total red blood cells transfused (median, range) was reduced from 1500 (0-9300) ml to 480 (0-2850) ml (P < 0.01) in the TA group. In hospital complications and mortality rates were not reduced in the TA group. CONCLUSION: Tranexamic acid reduced blood loss and the need for blood product transfusion and appears to be an effective treatment for patients undergoing reoperative cardiac valvular surgery.

Antifibrinolytic Agents↗
PubMed1997

Plexosarcoma of the bladder.

Plexosarcomas are rare soft tissue sarcomas, previously reported in association with gastrointestinal autonomic nerve (GAN) plexi. We report the first case arising from the autonomic nerve plexus of the bladder.

Humans↗
PubMed1997

Delay in treatment for oesophageal cancer.

BACKGROUND: Dysphagia is the cardinal symptom of oesophageal cancer, yet many patients present late. This study examined prospectively the interval between onset of dysphagia and treatment and identified reasons for delay. METHODS: Patients with histologically confirmed oesophageal carcinoma were questioned about duration of symptoms and about each step of their diagnostic work-up. Delay was estimated from date of onset of symptoms to definitive treatment. RESULTS: Median delay was 15 weeks for 78 patients with dysphagia, and 17 weeks for 22 patients with other symptoms. The most frequent cause of delay was late presentation to the family doctor (44 per cent). For patients treated with surgery alone there was a trend towards more advanced stage of disease with longer delay to treatment, but no correlation with survival (P = 0.25). CONCLUSION: Lack of awareness of the sinister significance of dysphagia is the most important cause for delay in presentation of patients with oesophageal cancer.

Adult↗
PubMed1996

Oral alendronate induces progressive increases in bone mass of the spine, hip, and total body over 3 years in postmenopausal women with osteoporosis.

To determine the effects of long-term daily oral alendronate sodium (ALN) on bone mass in postmenopausal women with osteoporosis, 19 centers enrolled 516 postmenopausal women aged 45-80 years with spine bone mineral density (BMD) at least 2.5 SD below the mean for young premenopausal women in a 3-year, double-blind, placebo-controlled study. Subjects were randomly allocated to one of four treatment groups: placebo; alendronate, 5 or 10 mg/day for 3 years; or alendronate, 20 mg/day for 2 years followed by 5 mg/day for the 3rd year. All patients received 500 mg/day of supplemental calcium to ensure adequate calcium intake. BMD was measured by dual-energy X-ray absorptiometry at several skeletal sites. Nonsignificant mean decreases in BMD of the spine, femoral neck, and trochanter of 0.6, 0.7, and 0.4%, respectively, occurred in the placebo group at 3 years. Relative to placebo-treated patients, spine BMD increased by 5.4%, 7.4%, and 8.4% in the 5, 10, and 20/5 mg ALN groups, respectively. Increases at the femoral neck were 3.5%, 5.5%, and 4.3%, and those at the trochanter were 5.1%, 7.2%, and 7.2%, respectively. Thus, efficacy of 10 and 20/5 mg ALN was similar, whereas the 5 mg dose was less effective. BMD continued to increase over the entire 3-year study duration in the ALN-treated groups and, compared with the other dosage groups, 10 mg ALN produced the largest gains in BMD during the 3rd year. Changes in biochemical markers of bone turnover and mineral homeostasis confirmed the effect of ALN to decrease bone turnover to a new steady-state level. The safety and tolerability of ALN were comparable with those of placebo. In summary, 10 mg daily oral ALN given for 3 years significantly and progressively increases bone mass and is a generally well-tolerated treatment for osteoporosis in postmenopausal women.

Administration, Oral↗
PubMed1996

Tumour marker detection in oesophageal carcinoma.

Levels of the tumour markers CEA, CA 19-9, CA 125 and SCC were measured in 58 patients presenting with oesophageal carcinoma and compared with levels in patients with benign oesophageal disease and levels in normal volunteers. CEA and CA 19-9 were significantly increased in the patients with oesophageal cancer, however, individual sensitivity for CEA, CA 19-9, CA 125 and SCC was only 28, 34, 10, and 32%, respectively. The combined sensitivity of all markers was 64% and specificity was 80%. There was no difference in combined tumour marker sensitivity between squamous or adenocarcinomas of the oesophagus. No consistent change in marker levels occurred with treatment, and tumour marker levels could not be significantly correlated with stage of disease or short-term survival. These results indicate that tumour marker sensitivity is too low for oesophageal cancer screening and has poor prognostic significance in those undergoing treatment.

Adult↗
PubMed1996

Medroxyprogesterone acetate enhances the spinal bone mineral density response to oestrogen in late post-menopausal women.

OBJECTIVES: The relative contributions of administered oestrogen and progestin to protection of the post-menopausal skeleton remain unclear. We have compared the effect on spinal bone mineral density of continuous combined oestrogen/medroxyprogesterone therapy with that of unopposed oestrogen in late post-menopausal women. DESIGN: Observational study. SUBJECTS: Seventy-three osteoporotic post-menopausal women attending the Auckland Hospital Bone Clinic. Twenty-three hysterectomized women were treated with unopposed oestrogen (0.625 mg oral conjugated oestrogens daily), and 50 non-hysterectomized women were treated with continuous combined oestrogen/medroxyprogesterone therapy (5 mg medroxyprogesterone acetate and 0.625 mg oral conjugated oestrogens daily). MEASUREMENTS: Baseline and one-year measurements of lumbar spine bone mineral density were performed using dual-energy X-ray absorptiometry. RESULTS: After one year of therapy, spinal bone mineral density increased by 6.6% (95% confidence interval 5.6-7.6, P < 0.001 vs baseline) in the combined oestrogen/medroxyprogesterone therapy group, compared to 4.0% (CI 2.4-5.7, P < 0.001 vs baseline) in the unopposed oestrogen group (difference between means 2.6% (CI 0.8-4.4, P < 0.01). CONCLUSION: In osteoporotic post-menopausal women, one year of continuous combined oestrogen/medroxyprogesterone therapy is associated with a 65% greater increment in spinal bone mineral density than is observed in response to unopposed oestrogen. The prescription of combined oestrogen/progestin therapy should be considered in osteoporotic post-menopausal women who have undergone hysterectomy, in order to maximize the skeletal protection provided by hormone replacement therapy.

Absorptiometry, Photon↗
PubMed1996

Bone mass and metabolism in women aged 45-55.

OBJECTIVE: Changes in calcium homeostasis and bone mass around the climacteric are poorly understood. We examined relations between endocrine factors and indices of bone mass and metabolism in healthy women approaching the menopause. DESIGN: Cross-section study. PATIENTS: Sixty-eight spontaneously menstruating women aged 45-55. MEASUREMENTS: Bone density measured at lumbar spine (LS) and femoral neck (FN) using dual energy X-ray absorptiometry and distal non-dominant forearm using peripheral quantitative computed tomography. We recorded menstrual history, physical activity and dietary calcium, and measured serum calcium, phosphate, alkaline phosphatase, osteocalcin, vitamin D, fT3, T4, TSH, PTH, FSH and oestradiol (E2), and urinary pyridinoline (PYD) and deoxypyridinoline (DPD) excretion. RESULTS: Using serum FSH level as a marker of ovarian function, 63 subjects could be classified into one of three groups: group A (serum FSH < 10 U/l, n = 29), group B (10-35 U/l, n = 27) and group C (> 35 U/l, n = 7). Bone density fell with declining ovarian function at the LS, FN and forearm trabecular (but not cortical) sites. Serum PTH was lower in group A vs B (mean (SD) 2.68 (0.97) vs 3.52 (1.17) pmol/l, P < 0.05), but similar to group C (2.90 (1.09) pmol/l, P = NS). Serum phosphate was elevated in group C compared to groups A and B (1.17 (0.15) vs 1.04 (0.11) and 1.05 (0.13) mmol/l, P < 0.05), and urinary PYD (61.1 (8.0) vs 50.4 (11.6) and 43.9 (8.1) mumol/mol creatinine) and DPD (15.9 (3.9) vs 12.0 (3.6) and 11.4 (3.6) mumol/mol creatinine) excretion were also increased. There were no significant differences in vitamin D metabolites or osteocalcin. Multivariate analysis suggested serum osteocalcin was positively related to physical activity and serum 1,25-dihydroxycholecalciferol levels. Serum free T3 was positively correlated with urinary DPD excretion, and inversely related to serum PTH. In all subjects, serum PTH was related to body weight (r = 0.38, P = 0.002). CONCLUSIONS: Declining ovarian function before menopause is accompanied by reductions in bone mass and altered calcium metabolism. Free T3 may regulate bone resorption and indirectly modulate PTH release.

Amino Acids↗
PubMed1994

LTP-like synaptic efficacy changes following electroconvulsive stimulation.

Synaptic plasticity is thought to represent a mechanism for memory formation. Memory disturbances commonly follow electroconvulsive therapy (ECT) for depression. Accordingly, we examined the development and duration of the effects of electroconvulsive stimulation (ECS) on hippocampal synaptic plasticity in rats. Daily recording of field potentials during 10 spaced ECS revealed an increase in the dentate gyrus evoked response, reaching a maximum after the fifth seizure. In a second experiment, an identical ECS series substantially reduced the degree to which electrically induced synaptic changes (long-term potentiation--LTP) could be elicited under anaesthesia for up to 40 days. These findings suggest that ECS induces LTP-like long-lasting synaptic changes which may underlie the neuropsychological sequelae of ECT treatment in humans.

Animals↗
PubMed1994

Testicular atrophy as a consequence of inguinal hernia repair.

Testicular atrophy is an uncommon but well recognized complication of inguinal hernia repair and one that frequently results in litigation. A series of ten cases of testicular atrophy occurring after hernia repair in nine patients is presented. Identifiable risk factors were present in eight instances. Surgeons should make careful enquiries as to previous groin or scrotal surgery and, when indicated, warn the patient before surgery of the increased risk of testicular atrophy. Overzealous dissection of a distal hernia sac, dislocation of the testis from the scrotum into the wound and concomitant scrotal surgery should all be avoided.

Adult↗