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Biomedical subjects

J May

Publications and source records attributed to J May.

At least 217 records · Page 12Linked to original sources
PubMed1986

Management of splenectomy failures in chronic immune thrombocytopenic purpura: role of accessory splenectomy.

Accessory splenic tissue was demonstrated in four of eight patients with chronic immune thrombocytopenic purpura investigated following post-splenectomy relapses. Time from initial splenectomy to relapse of thrombocytopenia ranged from immediately to eight years and post-splenectomy changes were present on the peripheral blood films of all patients at time of relapse. Three scanning techniques were employed to demonstrate and localise residual splenic tissue. Conventional 99mTc scans were positive in three of the four patients whilst 99mTc-heat damaged red cell scans and computerised tomographic scans were each positive in three out of three patients including the one patient in whom a conventional 99mTc scan was negative. Histological confirmation of splenic tissue was obtained in all cases with the weights of the accessory spleens ranging from 0.6 g to 2 g. Two patients responded to accessory splenectomy and, without immunosuppressive therapy, have remained well with normal platelet counts for over four years. There was no correlation between length of initial remission and the response to removal of the accessory spleen. The presence of a functioning accessory spleen should be considered in all patients with chronic ITP who fail to respond to, or relapse following, initial splenectomy.

Adult↗
PubMed1985

Long-term follow up of experimental microvascular grafts using Doppler ultrasound.

Non-directional Doppler ultrasound was used to determine patency in prosthetic microvascular grafts in 30 rats over 24 weeks. Examinations were carried out every two weeks and exploration and arteriography were used at intervals during the study to confirm the Doppler findings. Two rats died and were excluded from the study. Twenty-six grafts were patent at the time of examination and these were correctly assessed by the Doppler technique. However, only one of two occluded grafts was correctly identified. Our results suggest that while this technique is sensitive, its specificity is low, and graft exploration may still be required to confirm patency. Doppler ultrasound may prove a useful non-invasive tool for long-term follow-up of experimental microvascular grafts if the false positive rate can be reduced by improved technique and further experience.

Animals↗
PubMed1985

Post-transplant acute renal failure in cadaver renal recipients treated with cyclosporine.

The outcome of patients with acute renal failure following cadaveric renal transplant has been evaluated in a prospective, controlled trial, comparing treatment with cyclosporine (CSA) to prednisone, azathioprine, and antilymphocyte globulin (AZA). There was a high incidence of acute post-transplant renal failure in both groups: 37 of 51 CSA and 31 of 45 AZA patients, due to the long exposure of kidneys to warm and cold ischemia. Onset of adequate renal function was delayed for three or more weeks in 27 (53%) CSA and only nine (20%) AZA patients, and the only predisposing factor found was donor hypotension. All nine AZA and 18 of the 27 CSA patients with prolonged oliguria subsequently had a spontaneous diuresis. Nine of the CSA patients were changed to azathioprine and prednisone because of suspected CSA toxicity, and eight of these kidneys began functioning within days, even though they had been oliguric for 21 to 83 days. Of these nine patients, five had adequate long-term function on AZA, three developed CMV infections that were fatal to two individuals, and two rejected their grafts. Plasma CSA levels fluctuated widely in all patients, but were not higher in any group, including those with prolonged oliguria. During the oliguric period, biopsy specimens proved rejection was more common in the nine patients who had their CSA stopped than in the other CSA patients, and seven of these nine developed a diffuse interstitial fibrosis that was thought to be a manifestation of CSA toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1985

Experimental microvascular polytetrafluoroethylene grafts: 6-month patency.

The efficacy of 1-mm internal-diameter polytetrafluoroethylene as a microvascular prosthesis is unclear. In this study, 8-mm-long segments of this material were implanted into the femoral arteries of 30 rats. Animals were examined every 2 weeks up to 6 months by Doppler ultrasound. Cumulative patency by the life-table method was 86.7 percent at 6 months. There were 26 patent grafts, 2 occlusions, and 2 deaths. Intimal hyperplasia adjacent to the anastomoses was seen in the native arteries. The pseudointima lining the grafts was cellular near the anastomoses but usually acellular in midgraft regions. It is concluded that if early failure does not occur, then good long-term patency is possible with 1-mm polytetrafluoroethylene in this setting and that patency is not dependent on development of a cellular pseudointima. Longer graft segments should be evaluated in future studies.

Actuarial Analysis↗
PubMed1985

Should polytetrafluoroethylene grafts be used in preference to saphenous vein for femoropopliteal arterial bypass?

Some surgeons have advocated using polytetrafluoroethylene (PTFE) as the graft material of choice for femoropopliteal arterial bypass so that the saphenous vein could be preserved for future cardiovascular surgery. We have examined our results to see if this approach could be justified in our patient population. PTFE was used for 101 femoropopliteal reconstructions in 96 patients (56 male and 40 female). Thirty-eight (40%) complained of debilitating claudication and 58 (60%) had limb-threatening ischaemia. There were 83 primary PTFE femoropopliteal reconstructions and 18 repetitive procedures after failure of an earlier ipsilateral bypass. Twenty-nine of the 101 PTFE grafts were anastomosed distally to the popliteal artery above knee and the remaining 72 below knee. At 5 years, the cumulative patency for all grafts was only 11%. The 4 year cumulative patency was better for claudicants (40%) than for those with threatened limb loss (11%) but two of the 38 claudicants required amputation when their grafts failed. Patency rates were not significantly affected by the site of the distal anastomosis or by a previous failed ipsilateral femoropopliteal bypass. Worthwhile limb salvage was achieved only by frequent re-operation. Our results with PTFE are not good enough to use it in preference to an adequate saphenous vein for femoropopliteal bypass.

Aged↗
PubMed1984

A model system for the biochemical study of luteinizing hormone/chorionic gonadotropin receptor synthesis.

A model system for the biochemical study of LH/CG receptor synthesis has been developed. Culture conditions for porcine granulosa cells were adapted that maximized the selective induction of LH/CG receptors by cAMP-inducing stimuli with an elimination of background LH/CG receptor appearance. It was found that the addition of FSH (1.5 micrograms/ml) or cholera toxin (10 ng/ml) 1 day after plating resulted in optimal induction of the LH/CG receptor (20-60 pg [125I]CG bound/micrograms DNA 72 h after addition) with virtually no LH/CG receptor appearance in the absence of added stimuli. Later additions of FSH or cholera toxin required insulin (1.0 microgram/ml) which alone caused background LH/CG receptor appearance in the absence of any additional stimuli. Furthermore, insulin increased the general rate of cellular protein synthesis, whereas FSH or cholera toxin each decreased it. Thus, the use of FSH or cholera toxin, without insulin, may enable one to detect the synthesis of the LH/CG receptor by metabolic labeling techniques where background protein synthesis has been lowered.

Animals↗
PubMed1984

Cerebellar targets of visual pontine cells in the cat.

The cerebellum receives visual mossy fiber input from the cerebral cortex via visual cells in the pons. We identified the regions of cat cerebellum that receive cerebral visual input by injecting orthograde tracers among physiologically identified visual pontine cells. Cerebellar labeling following these injections indicates that the contralateral paraflocculus and the rostral folium of the uvula (vermal lobule IX) receive the heaviest projection from cortically activated pontine visual cells. Lighter visual input reaches much of the rest of the contralateral posterior lobe. A second experiment combined, in the same animal, orthograde tracing of the visual corticopontine pathway with retrograde tracing of the pontocerebellar projection. The results of this experiment confirm that the paraflocculus and uvula receive more cortical visual input than do other regions of the cerebellum. This experiment also shows that uvula-projecting and paraflocculus-projecting cells occupy different parts of the ventromedial pons. Uvula-projecting cells cluster immediately adjacent to the ventral and medial borders of the pyramidal tract and near the midline. Paraflocculus-projecting cells lie ventral and medial to the pyramidal tract but displaced from its border. There are few paraflocculus-projecting cells near the midline.

Animals↗
PubMed1984

A non-cholinergic function for acetylcholinesterase in the substantia nigra: behavioural evidence.

Acetylcholinesterase is released from substantia nigra neurons, independently of cholinergic transmission. In an attempt to discover the functional significance of this phenomenon, the behavioural effects of injecting acetylcholinesterase into one substantia nigra of the rat were investigated. Following a single injection of the enzyme, intraperitoneal amphetamine evoked circling behaviour in a direction away from the side of injection. Purified acetylcholinesterase with a similar electrophoretic mobility to the endogenous secreted form, was far more potent in eliciting circling than much higher activities of commercial enzyme, consisting of several molecular species of acetylcholinesterase. Similar infusions of butyrylcholinesterase did not induce circling. Depending upon the amount of enzyme initially given, the behavioural effects of a single injection of acetylcholinesterase persisted for up to thirty days. During this period apomorphine, administered systemically, induced transient circling towards the acetylcholinesterase-treated side. It is concluded that secreted acetylcholinesterase has a functional significance within the substantia nigra, independent of cholinergic transmission. This released enzyme could exert long-term changes in the activity of the nigrostriatal system, involving modification of dopamine striatal receptors.

Acetylcholine↗
PubMed1984

Shoulder girdle resection for giant basal cell carcinoma.

Forequarter amputation may seem the only surgical option when a tumour of the scapula or its overlying soft tissues invades the bones of the shoulder joint. As illustrated in this case of giant basal cell carcinoma, shoulder girdle (Tikhor-Linberg) resection is occasionally, possible, thus preserving a functional arm.

Bone Neoplasms↗
PubMed1984

Doppler ultrasound in the evaluation of experimental microvascular grafts.

A study was made to evaluate the accuracy of Doppler ultrasound in assessing patency in experimental microvascular grafts in rats. In 20 animals, pre-operative assessment produced a phasic wave form and audio signal consistent with arterial flow when the Doppler probe was placed over the groin crease. Ten animals then had a sham operation exposing the femoral vessels through a groin crease incision. The remaining 10 had a 10 mm segment of femoral artery excised to simulate an occluded graft. These animals were re-assessed 18 to 20 days later and the wave form and audio signal of arterial flow were detectable in the sham operated animals with the probe placed below the groin incision. No signal was elicited at this site in the animals whose femoral arteries had been excised. When these principles were applied to 20 rats with microvenous grafts and 20 with 1 mm PTFE grafts in the femoral artery we predicted graft patency with 100% accuracy. This non-invasive technique is inexpensive and highly accurate.

Animals↗
PubMed1984

One millimetre polytetrafluoroethylene (Gore-Tex) as a microvascular prosthesis: technique and early patency.

We have described a technique for grafting 1 mm internal diameter polytetrafluoroethylene (Gore-Tex) to the rat femoral artery. By spatulating the ends of the recipient artery and completing the proximal anastomosis before commencing the distal one, gentle and accurate suture placement is assured. At a mean of 40 days postoperatively (range 35-42 days) 16 of 20 Gore-Tex grafts (80%) were patent compared with 17 of 20 autogenous femoral vein grafts (85%). Examination of the prosthetic grafts by light microscopy and scanning electron microscopy showed incomplete development of a cellular lining and some areas of neo-intimal hyperplasia. One millimetre Gore-Tex provides excellent early patency as a microvascular graft in this experimental setting but long term patency is still undetermined.

Animals↗
PubMed1984

Limitations of human umbilical vein grafts.

Sixty modified human umbilical vein (HUV) grafts were used for arterial reconstruction in 48 patients between December 1979 and December 1981. Forty-four patients had limb-threatening ischemia (rest pain or tissue loss) and four had disabling claudication. Thirty-four patients had HUV grafting after a primary arterial reconstruction had failed. Fourteen had HUV used for their initial arterial bypass. The distal anastomosis was to the popliteal artery in 27 grafts (5 above and 22 below the knee) and the distal calf arteries in 33 (anterior tibial 10, posterior tibial 9, peroneal 14). The cumulative patency rate, calculated by the modified life-table method, was 34% at 1 year and 18% at 2 years. Fifteen patients required major amputation after graft failure; 13 of these healed below the knee. Preoperative and postoperative ankle/brachial systolic pressure indices and intraoperative blood flow did not correlate with graft failure. These results reflect the limitations of HUV as a graft material in patients with severe ischemia of the lower extremities. The prognostic factors that determined the outcome of arterial reconstruction with HUV in these patients remain to be defined.

Aged↗
PubMed1983

Appendicectomy audit.

Of 200 consecutive appendicectomies performed at Royal Prince Alfred Hospital the indications for operation were suspected acute appendicitis (65%), chronic or recurrent appendicitis (11.5%), interval appendicectomy (3%) and appendicectomies incidental to other operations (20.5%). Of those operated upon for suspected acute appendicitis, the appendix revealed acute inflammation pathologically in 64% of patients. Pathological changes occurred with the same frequency in both the incidental appendicectomy group and the chronic appendicitis group. Within the group with a provisional diagnosis of acute appendicitis there were marked variations in the documentation of peroperative symptoms, signs and investigations. On average 11.5 hours passed between the time these patients presented and when appendicectomy was performed. The patients spent an average of 6.4 days in hospital and only 33% had any documentation follow-up in the hospital records. Auditing systems can only be instituted in Australia if the structure of medical services is borne in mind. Adoption of overseas systems based on different patterns of medical care will add little to patient care.

Appendectomy↗
PubMed1983

Proximal aortic cross clamping during non-aortic surgery.

Temporary control of the aorta at the level of the diaphragm above the origins of the major visceral arteries is of proven value in the management of complex aortic disease including ruptured aneurysm, 're-do' aortic surgery and for aortic trauma. The value of the technique in elective non-aortic surgery is less well known. Two patients, one with a massive leiomyosarcoma of the stomach and the other with blood loss complicating a distal splenorenal shunt, are described in which proximal aortic control was of use.

Adult↗