Biomedical subjects
Publications and source records attributed to S Rajaratnam.
We report a case of duodenal malrotation that presented in adulthood as midgut volvulus. On colour Doppler ultrasound, findings of a clockwise rotation of the superior mesenteric vein around the superior mesenteric artery (whirlpool sign) and a distinctive 'whirl'-like pattern resulting from an encircling of loops of the bowel around the SMA on CT is diagnostic of midgut volvulus.
We report the results of a prospective randomized controlled trial, which looked at the incidence of postoperative diabetes insipidus (DI) following the use of three different hydrocortisone protocols, and the results of a study, on the incidence of DI and cortisol response in patients not given hydrocortisone. In study 1, 114 patients with pituitary macroadenoma were randomized into three groups: conventional dose (inj. hydrocortisone 100 mg IV 6-hourly for 3 days); intermediate dose (inj. hydrocortisone 100 mg IV 6-hourly on day 1, 100 mg IV 8-hourly on day 2, and 100 mg IV 12-hourly on day 3); low dose protocol (inj. hydrocortisone 25 mg IV 6-hourly on day 1, 25 mg IV 8-hourly on day 2 and 25 mg IV 12-hourly on day 3). Radical excision was achieved in 92 patients. The incidence of DI with the conventional dose was 52%, intermediate dose, 36% and low dose, 24% (p = 0.025). Study 2 included 16 consecutive patients with Hardy's grade A & B pituitary adenoma. These patients were randomized to receive (Group I) or not receive (Group II) hydrocortisone. Patients in Group II demonstrated normal cortisol response intraoperatively and no patient developed features of hypocortisolism; the incidence of DI in this group was 14%. The low dose hydrocortisone protocol reduced the incidence of DI by 46% when compared with the conventional dose hydrocortisone protocol. In patients with grade A and B tumour with normal preoperative cortisol levels, the use of perioperative hydrocortisone can be avoided.
Posterior dislocation of the sternoclavicular joint is an uncommon injury. Since 1824, when Sir Astley Cooper described the injury, little more than 100 cases have been described, and the majority of these have been in the last decade, identified by computed tomography. The significant morbidity and mortality associated with this injury is based upon serious damage to important anatomical structures found in the vicinity of the joint. We present a case report, describe the relevant clinical anatomy of this region, and review associated complications.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Large quantities of antigen in an immunoassay system impair antigen-antibody binding, resulting in low antigen determination. This is called the 'high dose hook effect'. We report this phenomenon in a patient with a large macroprolactinoma. In this patient, the correct estimate of serum prolactin (PRL) was obtained only after appropriate dilution of serum. We suggest that in order to avoid the high dose hook effect, the serum PRL be estimated in appropriate dilution in all patients with large pituitary tumours. This is particularly important when the clinical suspicion of high PRL is strong, as in women with amenorrhoea-galactorrhoea and men with long standing hypogonadism.
Symptomatic ossification of the posterior longitudinal ligament (OPLL) of the cervical spine is a rare but well-documented condition. It is the causative factor in up to 5% of cases presenting with cervical radiculopathy or myelopathy. Computed tomography is the modality of choice in showing the distinctive characteristics and extent of the disease. Magnetic resonance imaging (MRI) is sensitive in detecting cord compression and its attendant complications. Cervical OPLL commonly affects those of middle and advanced age, and the condition is noted to be particularly common in Japanese, although other racial groups are also affected. A 'mushroom' or 'hill' shape on axial CT typifies OPLL. A sharp radiolucent line separating the posterior vertebral margin from the superficial component of the ossified ligament is a characteristic feature.
BACKGROUND: Spontaneous diabetes insipidus (DI) is an uncommon disorder. This study analysed aetiology and response to treatment in patients with spontaneous DI admitted to the endocrinology service of a teaching hospital. METHODS: Twenty patients were seen over a eight year period (1991-1998). The diagnosis of DI was confirmed in each case by the standard water deprivation test. Appropriate diagnostic procedures were carried out to determine aetiology. RESULTS: Sixteen patients had complete DI and four patients had partial DI. Eighteen had central DI and two nephrogenic DI. The etiology in sixteen of the eighteen patients with central DI included: histiocytosis--three, eosinophilic granuloma--two, neurosarcoidosis--three, viper-bite--one, head injury--two, germinoma--one, post RT--one, tuberculous meningitis--one, acute-sphenoid sinusitis--one and hypothalamic tumour--one. Eleven patients (61%) responded to tab. carbamazepine, while nine (45%) required intra-nasal DDAVP. One of the two patients with nephrogenic DI responded to thiazide diuretic. CONCLUSION: We identified the aetiology in 88% of our patients with central DI. Histiocytosis and sarcoidosis accounted for 40%. Most patients (61%) responded to treatment with oral carbamazepine, others required intra-nasal DDAVP.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
There is considerable interest in dose to the breast in patients undergoing mantle treatment for Hodgkin's disease. This is because the patients are quite young (adolescents) and the latency period between irradiation and appearance of tumors is long. In a prospective study TLD chips were placed in several positions on the breast of the patients undergoing mantle treatment. Some parts of the breast were in the irradiated region. TLDs were placed under 2 and 3 cm of superflab bolus. Mantle field is irradiated with 10MV X-rays with a 2 cm spoiler placed 15 cm from the patient's skin. Treatment is given at 120 cm SAD. Doses in the range of 20-30 cGy per fraction were measured underneath the blocks in most cases, and doses of 30-50 cGy were measured at the edge of the block. The prescription is 200 cGy per fraction. The implication of these results will be discussed.
The authors review the literature and report their experience with radiation treatment of 39 prosthetically augmented or reconstructed breasts in 37 patients with primary or recurrent breast cancer. Group 1 consisted of 10 patients (12 primary breast cancers), of whom six had undergone previous breast augmentation and were later treated with lumpectomy and radiation therapy. Four patients were treated with mastectomy, reconstruction, and postoperative irradiation. Local tumor control was achieved in all patients. Excellent or good cosmetic results were achieved in all but two patients. Group 2 consisted of 27 patients with recurrent breast cancer after mastectomy and reconstruction. Local tumor control was achieved in 78% (21 of 27), with a mean duration of 34 months. Excellent or good cosmetic results were achieved in 93% (25 of 27). Patients who develop primary or recurrent breast cancer in prosthetically augmented or reconstructed breasts can be offered radical radiation therapy, with satisfactory tumor control and aesthetic results.
The cytotoxicity of 3 electron-affinic radiosensitizers has been studied in Chinese hamster V-79 cells as a function of pH and modest hyperthermia. When equitoxic concentrations were used and temperature was increased from 34 to 41 degrees C metronidazole, the compound with the lowest electron affinity showed the greatest enhancement of hypoxic-cell toxicity, and nitrofurantoin, the compound with the highest electron affinity, the least. The results can be explained if the mechanisms of toxicity involves a redox reaction, since it would be expected that the least toxic compound (lowest electron affinity) would have the largest activation energy and hence the greatest temperature effect. This appears to hold for these 3 compounds. Experiments also showed that nitrofurantoin which exhibits no increase in toxicity when the temperature was increased from 37 to 41 degrees C at pH 7.4, showed an increase in toxicity for the same temperature change at the pH of 7.0 and 6.6. Under aerobic conditions only metronidazole showed significant toxicity at 41 degrees C, where the differential between aerobic and hypoxic cell toxicity was minimal, both at pH 7.4, and at the low pH values of 7.0 and 6.6. In the clinical setting there is evidence that tumour cells are at a lower pH than their surrounding normal tissues. Hypoxic-cell cytotoxicity is enhanced at low pH, and even further enhanced at low pH in combination with a temperature of 41 degrees C. However, this finding correlates conversely with electron affinity. Thus, the radiosensitizer (and trichomonicide) metronidazole is most influenced by low pH and high temperature with the nitroimidazole, misonidazole, demonstrating a smaller enhancement due to higher temperatures.
Both published and new data on the interaction of electron-affinic drugs with hyperthermia with and without irradiation are reviewed for systems both in vitro and in vivo. Modest (sublethal) hyperthermia (41 degrees C) augments the differential hypoxic cytoxicity of some electron-affinic agents. Although hypoxic cytotoxicity increases with electron affinity, the thermal enhancement factors decrease. This finding is further evidence that hypoxic cytotoxicity and radiosensitization occur by different mechanisms. Furthermore, sublethal exposure of hypoxic cells to these agents makes them sensitive to killing by heat, which implies that because, under some circumstances, chronically hypoxic, unlike acutely hypoxic, cells can be thermally tolerant and could be important in the hyperthermic treatment of tumors.
Explore the source record for details and available documents.