Cerebral hemorrhagic risk of aspirin or heparin therapy with thrombolytic treatment in rabbits

We studied the incidence of cerebral hemorrhage in an animal model of embolic stroke to determine the safety of aspirin, heparin, and tissue plasminogen activator therapies. We occluded the middle cerebral arteries of rabbits with labeled blood clots and administered either tissue plasminogen activator, heparin, aspirin, tissue plasminogen activator plus aspirin, tissue plasminogen activator plus heparin, or saline at various times after stroke. Compared to saline controls, both the aspirin-only and the tissue plasminogen activator-plus-aspirin groups had a significantly higher incidence of cerebral hemorrhage, whereas the heparin and tissue plasminogen activator combination groups did not. We conclude that aspirin antiplatelet therapy alone may increase the risk of hemorrhagic infarction, whereas heparin or tissue plasminogen activator therapy appears to be relatively safe.     

The long-stem bipolar prosthesis in surgery of the hip

More than 500 hips, with either displaced fractures of the femoral neck or primary or revision total hip arthroplasty, were treated by a straight, long-stem (305-mm), Bateman-type bipolar model (BBM). The BBM was not porous coated, and it is not cemented in place. The femoral component is secured in the femoral canal by means of biomechanical fixation. It is biologic by bone ingrowth through the fenestration in the proximal neck. It is mechanical by a snug fit in the isthmus and by three-point fixation within the shaft. The removed femoral head is morselized in the bone mill and packed into the prepared femoral canal to enhance a tight fit. The collar of the BBM transfers stress to the calcar. Postoperative roentgenograms show incorporation of bone graft within the fenestration of the prosthesis and no stress shielding of the calcar. The acetabulum requires reaming only if it is shallow or asymmetric. It usually presents no problem except in revision total hip arthroplasty. The present authors have used the BBM almost exclusively since 1981. After eight years, the BBM has stood up well to the test of time and presented few major problems.     

Growth of melanocytes in human epidermal cell cultures

Epidermal cell cultures were grown in keratinocyte-conditioned medium for use as burn wound grafts; the melanocyte composition of the grafts was studied under a variety of conditions. Melanocytes were identified by immunohistochemistry based on a monoclonal antibody (MEL-5) that has previously been shown to react specifically with melanocytes. During the first 7 days of growth in primary culture, the total number of melanocytes in the epidermal cultures decreased to 10% of the number present in normal skin. Beginning on day 2 of culture, bipolar melanocytes were present at a mean cell density of 116 +/- 2/mm2; the keratinocyte to melanocyte ratio was preserved during further primary culture and through three subpassages. Moreover, exposure of cultures to mild UVB irradiation stimulated the melanocytes to proliferate, suggesting that the melanocytes growing in culture maintained their responsiveness to external stimuli. When the sheets of cultured cells were enzymatically detached from the plastic culture flasks before grafting, melanocytes remained in the basal layer of cells as part of the graft applied to the patient.     

Adult age differences in visual acuity, stereopsis, and contrast sensitivity

We investigated adult age differences in four measures of visual function: distance acuity, near acuity, stereopsis, and contrast sensitivity. Twenty-four young adults (mean age 19.5 years) and 24 older adults (mean age 68.4 years) participated. Age differences were present in each of the four measures. A stepwise discriminant analysis performed on the four measures revealed that, when the correlations among the measures were taken into account, only contrast sensitivity significantly discriminated young and older adults' performance. The strength of the correlations among the four measures was greater for older adults than for young adults. The results indicated that contrast sensitivity is a useful measure for detecting age-related changes in visual function and that a common mechanism may underlie age differences on various visual tests.     

The role of low fat diets in the management of gall-bladder disease

This paper presents the results obtained from 87 questionnaires completed by dietitians about the dietary management of gall-biadder disease. Of the patients referred to the dietitians, 86% were referred by surgeons. Of the dietitians that responded 77% thought that there was a role for low fat diets in the management of these patients; 92% would advise a low fat diet to help avoid pain, and 11% would advise a low fat diet to patients with gall-bladder disease who did not have pain, steatorrhoea or obesity.
The paper reviews the available evidence concerning the effect of dietary fat on the gall-bladder; it is concluded that, at present, there is little data to support the therapeutic use of a low fat diet for individuals with gall-stones.     

Alcohol: The Ambiguous Molecule.: By Griffith Edwards. Penguin Books, London. 2000, 230pp. paperback, {pound}7.99. ISBN: 0-14-126666-6.

The title points to society’s contradictory views of alcohol,to the seductiveness of alcoholic beverages and to their potentialfor harm. Professor Edwards, who is the doyen (worldwide) ofstudies on alcohol policies     

Surgical staging of gastric carcinoma: sources and consequences of error

Macroscopic 'TNM' staging was performed during 78 consecutive operations for gastric carcinoma and compared with subsequent pathological staging. Surgical assessment was correct for tumour (T) in 60 per cent when depth of invasion was assessed, for nodes (N) in 61 per cent, for liver metastases (M) in 92 per cent but for all aspects in only 21 per cent. Curability (conservatively defined as T1-3, N0-1, M0) was correct in 8 of 18 patients thus assessed at surgery and incurability was pathologically correct in 58 of 60 patients. Despite inaccurate surgical staging, no patient was denied a resection although 10 patients had unduly radical procedures for their stage and 2 had inappropriately conservative procedures for their stage (but without evidence of residual disease). Staging errors did not jeopardize conventional surgical management substantially and use of intra-operative microscopic sampling of nodes would have improved surgical treatment only minimally.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.