T cell subsets mediating rejection of established fetal pancreas grafts and failure to observe graft adaptation

The present study has attempted to elucidate the cellular mechanisms by which long-term established fetal pancreas allografts are rejected. We used an experimental model in which H-2b nude mice were made hyperglycemic by streptozotocin treatment and then engrafted with allogeneic fetal pancreas grafts. These grafts were functional in that engrafted animals returned to near normoglycemia while all animals left unengrafted subsequently died. The fetal pancreas grafts were allowed to reside in the immunoincompetent nude host for 6-9 months prior to T cell reconstitution, at which time animals were reconstituted with either negatively selected CD4+ or CD8+ H-2b T cell subpopulations. We found that a 6-9 month residence in an immunoincompetent host did not lead to a change in the immunogenicity of fetal pancreatic grafts in that both CD4+ and CD8+ T cell subsets were capable of rejecting these long-term established fetal pancreas grafts. The finding that isolated CD8+ spleen T cell subpopulations, which are only activated by antigen-presenting cells of donor origin bearing MHC class I alloantigen, were capable of effecting graft rejection suggested that APC of donor origin persisted in these long-term fetal pancreas allografts.     

Cemented and ingrowth fixation of the Miller-Galante prosthesis. Clinical and roentgenographic comparison after three- to six-year follow-up studies

One hundred thirty-nine cemented and 132 cementless Miller-Galante total knee prostheses were followed between three and six years (average, 43-44 months). The fixation technique was based on patient age, bone quality, and ability to delay full-weight bearing. Clinical follow-up studies were possible on 116 cemented knees. Fifteen knees were lost because of death before the three-year follow-up study, and eight knees required component removal. One hundred twenty-three cementless knees were available for clinical follow-up studies; there were three deaths, and six failures required component removal. No cemented failure was due to fixation, and three cementless failures were due to lack of tibial ingrowth in two and pain of undetermined etiology in one. Preoperative knee scores were slightly significant with cemented knees averaging 48 points and cementless knees averaging 52 points. A similar significant difference was maintained at the final follow-up study. No significant differences were noted for pain, limp, or support scores. Average range of motion was similar in the two groups. Radiolucent lines about the femoral component were rare. Cementless tibial radiolucencies were partial in up to 20% of examined zones, and complete tibial tray radiolucency was seen in only three patients. No correlation between radiolucency and knee scores was seen.     

Botrocetin agglutination of rat megakaryocytes: a rapid method for megakaryocyte isolation.

Botrocetin isolated from the venom of Bothrops jaracara has been shown by others to induce binding of von Willebrand Factor to glycoprotein Ib and thereby produce platelet agglutination in a wide range of animal species. We have found that botrocetin also facilitates the agglutination of megakaryocytes and have used this property to develop a method to isolate megakaryocytes from rat bone marrow. When botrocetin is added to a mixture of rat bone marrow, rat platelets, and rat plasma, coagglutination of megakaryocytes and platelets occurs. The agglutinated complexes, containing > 95% of the megakaryocytes, may then be separated from the remaining marrow cells by filtration. Megakaryocytes account for 39% (range 30%-48%) of the isolated cells and 83% (range 77%-88%) of the isolated cell mass. This method allows the virtually complete removal of megakaryocytes from bone marrow as well as their isolation to a high degree of purity. It should provide a useful, inexpensive, general method for the rapid isolation of megakaryocytes from multiple, small marrow samples from a wide range of species.     

Knee-chest vs horizontal side position during induction of spinal anaesthesia in patients undergoing lumbar disc surgery

In the prone knee-chest position the spread of plain 0.5% bupivacaine in the cerebrospinal fluid and associated haemodynamic changes may be different compared with the horizontal position. A randomized comparison was performed in 40 ASA I-II patients, aged 24-61 yr, undergoing lumbar disc surgery. Subarachnoid injection (27-gauge needle) at the L2-3 interspace with 3 ml of 0.5% bupivacaine was performed with the patient in the operative knee-chest position (prone knee-chest group, n = 20) or in the horizontal side position (supine side horizontal group, n = 20). Patients in the supine side horizontal group were turned into the horizontal supine position for 20 min, and subsequently they were placed in the operative knee-chest position. In three patients in the prone knee-chest group, the spinal needle was replaced by a larger needle (25-gauge). The final cephalad extension of sensory analgesia on skin tested by pinprick was T5 (median) in the prone knee-chest group and T6 in the supine side horizontal group. Recovery was also similar, on average 210 min from injection in both groups. The mean decrease in systolic arterial pressure was somewhat greater in the prone knee-chest group (30 mm Hg) than in the supine side horizontal group (13 mm Hg). The need for ephedrine occurred earlier in the supine side horizontal group (three patients, all within 10 min from local anaesthetic injection) than in the prone knee-chest group (six patients, all after 15 min). Four of the latter patients also required administration of an anticholinergic for bradycardia compared with two patients in the supine side horizontal group. Light sedation was given to five patients in the prone knee-chest group and to four in the supine side horizontal group because of numbness and aching in the shoulders. We conclude that spinal block was similar in the two groups but there was a tendency to more frequent episodes of haemodynamic deterioration in the knee-chest position.      

Hypothesis: Pathogenesis of postmenopausal hot flush

The pathogenesis of postmenopausal hot flush is still poorly understood. A hypothesis is presented where the perimenopausal decline in circulating estrogen levels may increase central norepinephrine and LH-RH secretion and produce a downward setting of the central thermostat resulting in a hot flush.     

Effect of thoracic epidural etidocaine 1.5% on somatosensory evoked potentials, cortisol and glucose during cholecystectomy

The effect of thoracic (T7-8) epidural etidocaine 1.5%, 9 ml, and continuous per- and postoperative epidural infusion of etidocaine 1.5%, 4 ml/h, on early (less than 500 ms) somatosensory evoked potentials (SEPs), and cortisol and glucose in plasma during cholecystectomy, was examined in ten patients. Spread of analgesia (pin-prick) was T3 (T1-T3) to L2 (T11-L3) 35 min after injection of etidocaine, and T3 (T2-T4) to T12 (T8-L4) 3 h after surgical incision (median (range)). Before operation, epidural etidocaine had no significant effects on peak-to-peak amplitude of SEPs to electrical stimulation at the L1, T10 or T6 dermatomal level (P greater than 0.09). SEPs were abolished in only two patients at T6, and no patient had SEPs abolished at T10 or L1. The plasma concentrations of cortisol and glucose were significantly increased 20 min after surgical incision and remained increased throughout the study. No correlation was found between the block-induced decrease in the peak-to-peak amplitude at T6 or T10 and increase in plasma cortisol, except for a negative correlation at T10 and the initial increase in cortisol (Rs = 0.72, P = 0.03). In conclusion, thoracic epidural administration of 9 ml of etidocaine 1.5% does not provide total afferent somatic blockade assessed by SEP and the stress response to cholecystectomy.