Failure of ablation of a mediastinal parathyroid adenoma by repeated contrast staining

In a patient with primary hyperparathyroidism an attempt was made to ablate a middle mediastinal parathyroid gland by forceful staining with radiographic contrast material. The gland was stained on two separate occasions, two weeks apart. Both times the serum calcium level temporarily fell to the normal range but reverted to abnormal levels. The patient ultimately required surgery for correction of hypercalcemia. The mechanism of staining and possible reasons for failure as well as potential complications are discussed.     

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     

Femoral component revision using an extensively hydroxyapatite-coated stem

Femoral component revisions with extensively coated stems have shown promising clinical results, although concerns over stress shielding still exist. We retrospectively reviewed 59 patients undergoing femoral component revision with an extensively hydroxyapatite (HA)-coated stem. The average length of follow-up was 3.3 years (range, 2-5 years). The average preoperative Harris Hip Score was 43 points, which improved to 86 points at the latest follow-up (P < .01). The overall mechanical failure rate was 2%. No evidence of stress shielding was seen in 78% of patients. The clinical results of this series using an extensively HA-coated stem are similar to those using an extensively porous-coated stem. Long-term follow-up is required to determine if an extensively HA-coated implant will be superior to an extensively porous-coated implant with regard to stress shielding.     

Pneumocystis carinii pneumonia studied by gallium-67 scanning

The validity and reliability of gallium-67 (Ga-67) scanning for diagnosis and follow-up of Pneumocystis carinii pneumonia (PCP) were assessed in 34 patients thought to have pulmonary complications of acquired immunodeficiency syndrome (AIDS). Overall sensitivity was 94% and specificity 74%. Among patients with normal or equivocal chest radiographs at the time of admission, sensitivity was 86% and specificity 85%. The authors consider Ga-67 scanning a valid and reliable adjunct in the diagnosis of PCP in AIDS patients with respiratory symptoms when the chest radiograph is normal or equivocal.