Gallium-67 lung uptake: conjugate-view technique

A conjugate-view technique is derived for calculation of absolute gallium-67 (Ga-67) uptake from scintillation-camera images. The technique combines counts of posterior and anterior images of the lung with an attenuation correction obtained from cobalt-57 (Co-57) transmission imaging. The formulation is such that the effects of Compton scatter build-up are accounted for. Studies utilizing a canine model indicated that, normally, more activity is located in the chest wall than in the lungs. The quantitative technique must therefore accurately account for a variety of Ga-67 distributions, including that in the chest wall. Calculations were performed using a three-component model comparing results obtained with the conjugate-view approach to the actual uptake. These calculations suggest that an assumption of uniform activity distribution allows an accuracy of approximately +/- 10% over a broad range of body-part thicknesses and uptake by the lungs. It was concluded that the conjugate-view technique is necessarily approximate but can provide clinically useful results.     

Platelet Functions in Cardiopulmonary Bypass Surgery

Background

Haemorrhage after Cardio Pulmonary Bypass (CPB) Surgery is a well recognised complication that leads to significant morbidity and mortality. The incidence varies between 5-25% depending upon the clinical situation. Several factors are implicated as causative but none have been precisely proved.

Methods

Our study was an attempt to evaluate the haemostatic defect with particular reference to platelet function abnormalities during cardio pulmonary bypass surgery, in order to reduce the morbidity and mortality associated with post CPB haemorrhage. Flow cytometric evaluation of different platelet glycoproteins like GPIb/IX, GPIIb/IIIa and GMP-140 was done.

Results

The marker expression showed deregulation during surgery which returned to base after bypass was terminated. In contrast, the cases with bleeding showed significant variation. P-Selectin (GMP 140) expression decreased progressively till 3^rd post-operative day showing lack of activation of platelets in cases of severe bleeding.

Conclusion

Longer duration of CPB initiates plasmin generation through heparin, which raises the PAI-1-tPA complex and thereby down regulating the functions of platelets. This suggests a link between duration of CPB, bleeding, platelet dysfunction and fibrinolysis. Hence serial estimations of the levels of GMP-140 and tPA can predict severe bleeding.Key Words: CardioPulmonary Bypass, Platelet dysfunction, flowcytometry, platelet glycoproteins, haemorrhage     

Temporal profile of neuronal damage in a model of transient forebrain ischemia

This study examined the temporal profile of ischemic neuronal damage following transient bilateral forebrain ischemia in the rat model of four-vessel occlusion. Wistar rats were subjected to transient but severe forebrain ischemia by permanently occluding the vertebral arteries and 24 hours later temporarily occluding the common carotid arteries for 10, 20, or 30 minutes. Carotid artery blood flow was restored and the rats were killed by perfusion-fixation after 3, 6, 24, and 72 hours. Rats with postischemic convulsions were discarded. Ischemic neuronal damage was graded in accordance with conventional neuropathological criteria. Ten minutes of four-vessel occlusion produced scattered ischemic cell change in the cerebral hemispheres of most rats. The time to onset of visible neuronal damage varied among brain regions and in some regions progressively worsened with time. After 30 minutes of ischemia, small to medium-sized striatal neurons were damaged early while the initiation of visible damage to hippocampal neurons in the h1 zone was delayed for 3 to 6 hours. The number of damaged neurons in neocortex (layer 3, layers 5 and 6, or both) and hippocampus (h1, h3–5, paramedian zone) increased significantly (p < 0.01) between 24 and 72 hours. The unique delay in onset of ischemic cell change and the protracte increase in its incidence between 24 and 72 hours could reflect either delayed-appearance of ischemic change in previously killed neurons or a delayed insult that continued to jeopardize compromised but otherwise viable neurons during the postischemic period.     

A clinician's guide to hereditary colon cancer

Approximately 10% of patients diagnosed with colorectal cancer are at risk for a hereditary form of the disease. At-risk patients can be offered genetic counseling and testing to determine whether they carry a detectable mutation for such a syndrome. If so, this information provides the clinician with valuable data about the patient's risk for other cancers, and what further surveillance and risk reduction options should be incorporated into the management plan. Mutation identification within a family also makes it possible for other family members to learn if they are at risk for the same syndrome. There are many hereditary colorectal cancer syndromes, and the clinician must know what essential information should be elicited from a family history and which patients should be referred for genetic counseling and testing.     

葛根素对高血压患者血浆内皮素和一氧化氮的影响

目的：检测正常人与高血压病（ＥＨ）患者血浆内皮素、一气体氮的变化及葛根素对其的干预效应。方法：ＥＨ对照组口服苯磺酸氨氯地平５ｍｇ／ｄ,或合和盐酸苯那普利１０ｍｇ／ｄ,每日一次,１５ｄ为一疗程。ＥＨ伍用治疗组同时合用５％ＧＮＳ２５０ｍｌ＋葛根素注射液４００ｍｇ静滴,两组治疗前后检测血浆ＥＴ、ＮＯ水平变化。结果：ＥＨ各组血浆ＥＴ较正常人组均显著增高（Ｐ〈０．０１）,血浆ＮＯ水平及ＮＯ／ＥＴ比值除轻度Ｅ