Tumour-to-normal uptake ratio of 90Y microspheres in hepatic cancer assessed with 99Tcm macroaggregated albumin

The selective delivery of a high dose of radiation to malignant hepatic tumours by infusion of non-biodegradable yttrium-90 (90Y) microspheres via the hepatic artery while sparing the non-tumorous liver parenchyma depends on the tumour-to-normal uptake ratio (T/N) of the therapeutic radiopharmaceutical. Using intrahepatic arterial technetium-99m macroaggregated albumin (99Tcm-MAA), the effect of tumour type, tumour vascularity assessed by hepatic angiography (HAG), tumour size and the degree of extrahepatic shunting on the T/N was investigated in 377 patients with hepatocellular carcinoma (HCC) and 25 patients with colorectal liver metastases. HCC was shown to have a wider range of T/N (0.2-26.5) compared with liver metastases (2.3-7.2). HCC with vascularity grade 1 on HAG had significantly lower T/N but there was no significant difference in HCC with higher vascularity grades. This confirmed that vascularity on HAG does not predict T/N. Overall there was no correlation between T/N and tumour size. Large tumours (> 20 cm) had a significantly lower T/N, probably due to necrosis in the tumour centres. A decrease in mean T/N with increasing percentages of lung shunting was observed in HCC. Determination of T/N by simulation with 99Tcm-MAA is recommended before internal radiation therapy with 90Y microspheres.     

T-cell subsets: recruiting the right kind of help

The qualitative features of immune responses are influenced by the polarization of helper T cells towards two distinct phenotypes, Th1 and Th2. Recent evidence suggests that these helper cell subsets may be differentially recruited to the sites of different types of inflammatory reaction.     

Incidence and clinical manifestations of HIV-1 infection in multitransfused thalassaemic Indian children

Four hundred and six multitransfused thalassaemic children attending the paediatric clinic in Manipur, India, were screened for HIV antibodies. There were 46 (8.9%) ELISA antibody-positive children and the diagnosis was reaffirmed by Western blot assay. The immunologic status of the seropositive children was evaluated by a) absolute lymphocyte count, b) percentage of ratio of T helper (CD4+) and T suppressor (CD8+) cells, c) quantitative Ig, G, M and A levels and d) delayed-type cutaneous hypersensitivity (DTH) testing. Twelve of the 36 seropositive children were clinically symptomatic with AIDS. The clinical and immunological status of seropositive children are compared with matched seronegative thalassaemic control groups. Five of the 12 symptomatic seropositive children had received continued antiretroviral treatment. The mortality rate at the end of 36 weeks of itinerary was 20% in contrast to 50% in the untreated children. This report highlights the value of early recognition and therapeutic intervention in a selected high risk paediatric population.     

Traumatic inferior vena caval injuries

Twenty-three cases of inferior vena caval injury (1.4% of all operatively managed abdominal injuries) are reviewed. The caval injury presented as free haemorrhage in 15 cases and as a retroperitoneal haematoma in eight. The site of vena caval injury was at or above the level of the renal veins in 14 cases (61%). Successful lateral suture repair was achieved in 18 cases (78%). The overall mortality rate was 39%. Factors positively associated with survival were stab wound, presentation as retroperitoneal haematoma, infrarenal injury, low Abdominal Trauma Index score and small peroperative blood loss. Concomitant injury to the abdominal aorta, liver or kidney worsened the prognosis. The crucial factor in management of inferior vena caval injuries is rapid and effective control of bleeding, whether from the caval or associated injuries.     

Sphincter preservation therapy for distal rectal carcinoma: a review

BACKGROUND: There has been increasing interest in the use of sphincter-preserving therapy for patients with distal rectal carcinomas. The outcomes of conservative treatments for early stage rectal carcinoma appear to be comparable to that achieved with abdominoperineal resection. METHODS: Retrospective and prospective clinical series of patients with distal rectal carcinoma treated by local excision alone, local excision with postoperative adjuvant therapy, preoperative radiation followed by local excision, or radical circumferential sphincter-sparing surgeries were reviewed. The local control rates, salvage rates, and treatment complications in patients treated by these various methods were examined. RESULTS: Patients with T1 distal rectal carcinoma with favorable clinical and histopathologic characteristics treated with local excision alone had a local control rate of greater than 90% in most series. Postoperative chemoradiation improved local control for those with T1 disease with unfavorable characteristics, or those with T2 disease. Most T3 patients had failure rates of greater than 30% despite adjuvant local and systemic therapy. With high dose preoperative radiation, approximately 80% of patients with locally advanced or unresectable tumors were able to undergo sphincter-preservation treatment. CONCLUSIONS: Patients with favorable T1 rectal carcinoma are likely to be adequately treated with local excision alone. Patients with T1 disease with unfavorable characteristics as well as T2 patients will benefit from postoperative chemoradiation. The use of local therapy in T3 patients needs to be carefully considered because these patients are at relatively high risk for local recurrence despite adjuvant therapy. Preoperative radiation followed by either local excision or radical circumferential sphincter-sparing resections appears promising in allowing sphincter preservation in patients with locally advanced tumors.     

Opposing roles for endogenous BDNF and NT-3 in regulating cortical dendritic growth

Neurons within each layer of cerebral cortex express multiple members of the neurotrophin family and their corresponding receptors. This multiplicity could provide functional redundancy; alternatively, different neurotrophins may direct distinct aspects of cortical neuronal growth and differentiation. By neutralizing endogenous neurotrophins in organotypic slices of developing cortex with Trk receptor bodies (Trk-IgGs), we found that BDNF and NT-3 oppose one another in regulating the dendritic growth of pyramidal neurons. In layer 4, both endogenous and exogenous NT-3 inhibited the dendritic growth stimulated by BDNF. In contrast, in layer 6 both endogenous and exogenous BDNF inhibited dendritic growth stimulated by NT-3. These antagonistic actions of endogenous BDNF and NT-3 provide a mechanism by which dendritic growth and retraction can be dynamically regulated during cortical development, and suggest that the multiple neurotrophins expressed in developing cortex represent distinct components of an extracellular signaling system for regulating dendritic growth.