Biomedical subjects
Publications and source records attributed to B C Lee.
Application of intermittent compression of the calf is described as an adjunct to maintain patency of femoral venous reconstruction following trauma. Its use in instances of femoral and popliteal venous reconstructions is recommended.
The clinical outcome of 88 profundaplasties in 70 patients operated upon during the period 1978 to 1982 was related to indications for operation, status of arterial run-off, influence of a concomitant inflow procedure, and changes in Doppler ankle-brachial index (ABI). Operative procedures were performed for rest pain (49 limbs), ulceration (24 limbs), and gangrene (13 extremities). Primary profundaplasty (PP) was performed in 26 (29%) cases. Sixty-two procedures (71%) were inflow profundaplasties (IP) performed in conjunction with other proximal reconstructions. Overall clinical success was achieved in 67 extremities (76%). When the operation was performed for rest pain, and the arterial run-off was good, success rate was 78 per cent and 79 per cent, respectively, as compared to 51 per cent and 57 per cent for ulceration/gangrene and poor arterial run-off. For PP, satisfactory outcome was noted in 69 per cent as compared to 79 per cent in IP. In the clinically successful profundaplasties, mean preoperative ABI was 0.29 and increased significantly to 0.53 postoperatively (P = 0.04). In the clinical failures, mean preoperative ABI was 0.32, and postoperative ABI was 0.38, which was not statistically significant (P greater than 0.05). Profundaplasty is a reliable operation particularly when the indication is rest pain, and the arterial run-off is good. Poor results can be anticipated when the procedure is performed for tissue loss, or if the arterial run-off is poor. Clinical outcome for the PP and IP groups were comparable.
A 3-year clinical experience is analyzed to define preferred surgical management and amputation rates for popliteal as well as infrapopliteal arterial injuries. Ten patients with popliteal arterial trauma were successfully managed without amputation, however, five of 11 (45%) patients with infrapopliteal arterial trauma required amputation. While essentially all popliteal arterial injuries mandate repair, recommendations for repair or ligation of isolated tibial arterial injuries are based on presence of distal ischemia, the patient's associated injuries, as well as estimated operating time for reconstruction. With injury to two or three infrapopliteal arteries, distal ischemia is usually present and arterial repair indicated, unless there has been severe crush injury, prolonged delay, or extended surgery would jeopardize the patient's life. A management protocol for patients with distal ischemia related to popliteal or infrapopliteal arterial trauma should include prompt surgical intervention, liberal use of fasciotomy, intraoperative arteriography, as well as the selective use of intraluminal shunts.
During a 4 year period (1979 through 1983), 181 major arterial (69 percent) and 81 venous (31 percent) injuries were treated surgically. Of the venous injuries, 24 (30 percent) involved the femoral veins (9 common femoral, 15 superficial femoral). Management of these femoral venous injuries included lateral venorrhaphy in 10 cases (42 percent), venous patch angioplasty in 5 cases (21 percent), end-to-end anastomosis in 4 cases (17 percent), interposition autogenous saphenous vein grafts in 3 patients (12 percent), and ligation in 2 cases (8 percent). One case that included common femoral venous ligation and one that included a failed interposition saphenous vein graft in the superficial femoral vein subsequently were managed with in situ saphenous vein bypass. For one interposition saphenous vein graft repair of the common femoral vein we utilized the spiral vein graft technique. Excluding one early death from associated injuries and one superficial femoral venous injury managed by ligation without postoperative complications, 17 of 23 (74 percent) femoral venous repairs were judged patent postoperatively (13 confirmed by venography and 4 by noninvasive testing). The adjuvant use of intermittent pneumatic calf compression and low molecular weight dextran appears to have been beneficial in maintaining patency of the femoral venous repairs. Early clinical follow-up demonstrated the presence of edema in 6 of 8 cases (75 percent) initially treated by ligation or complicated by postoperative occlusion. Early postoperative edema, present in 4 of 17 (24 percent) patients with patent venous repairs, had resolved by the time of discharge. We recommend routine repair of femoral venous injuries. When significant edema or ischemia develop following obligatory venous ligation or postoperative occlusion of a venous repair, revision or venous bypass should be considered.
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Homogenous preparations of primary Sertoli cell cultures were obtained from the testes of the macaque of different ages. The characteristics of Sertoli cells were confirmed by electron microscopy. Sertoli cell cultures were segregated into three developmental age groups: prepubertal, pubertal, and adult. The highest response to follicle-stimulating hormone [FSH (NIH-FSH-S13) as measured by cAMP and testosterone to estradiol conversion occurred in Sertoli cells from pubertal animals, whereas the responses were diminished in cells from both younger and older animals. Specific binding of 125I-human FSH was also increased in Sertoli cells prepared from pubertal animals when compared to cells from the other two age groups. These data demonstrate: 1) the utility of primate Sertoli cells as an in vitro model, and 2) the age-related differences in monkey Sertoli cell response to FSH and to specific FSH receptor binding.
Three different doses of a potent antagonist to GnRH, [Ac-delta 3Pro1, pFDPhe2, DTrp3,6], GnRH were compared in adult male monkeys to determine the acute effect on pulsatile gonadotropin secretion. In accomplishing these studies, blood was drawn at 15 min intervals over 24-30 h without anesthesia using a mobile vest and tether assembly to support an indwelling cannula. After a 3 to 6 h control period, 2.0, 0.2 or 0.02 mg GnRH antagonist/kg bw in 1 ml corn oil sc, was given to castrate adult monkeys. The highest dose decreased circulating LH (by radioimmunoassay and bioassay) and FSH whereas the intermediate dose decreased LH only. The higher dose produced both a more prolonged and greater reduction in circulating gonadotropins. These data demonstrate that this GnRH antagonist can reduce serum gonadotropins both acutely and for intervals greater than 24 h.
Pulsatile secretion of serum gonadotropins and testosterone was studied in 46 monkeys of varying ages from 9 days of age through adult life. Although some of the hormonal analysis was longitudinal in nature, most comparisons were cross-sectional. On the basis of pulsatile secretory patterns, hCG and GnRH stimulation, skeletal age, testicular volume, and histology, we have arbitrarily defined four developmental age groups: postnatal (less than 7 months), prepubertal or juvenile (7-27 months), pubertal (28-59 months), and adult (greater than or equal to 60 months). In accomplishing the pulsatile studies, blood was withdrawn at 15-min intervals over 24 h without anesthesia using a mobile vest and tether assembly to support an indwelling cannula. GnRH and hCG challenge tests were done on one or more occasions on all animals. Plasma samples were analyzed for concentrations of FSH, LH, testosterone, dihydrotestosterone and delta 4-androstenedione by established RIAs and an in vitro bioassay for LH. During the frequent sampling period of 24-h duration for all except postnatal animals, testosterone pulses of large amplitude (up to 8-fold) occurred in postnatal, pubertal, and adult animals. Pulsatile gonadotropin secretion was seen at all ages; however, the highest pulses (up to 15-fold) occurred in prepubertal animals even though this was an infrequent occurrence. Time series analysis techniques were applied for objective statistical characterization of cyclic patterns. Basic rhythms corresponding to 50- to 90-min frequency cycles in gonadotropin secretion were identified. Substantive differences between LH concentrations by bioassay and RIA were seen infrequently. Our findings illustrate that: 1) circulating gonadotropin and testosterone pulses change in amplitude but not necessarily frequency during pubertal development, and 2) primate models are a useful paradym for the longitudinal study of human male sexual development. We conclude that where direct human investigation may be limited, much can be learned by study of these primate surrogates.
Pulsatile secretion of serum gonadotropins was studied in 16 castrated monkeys from 4 weeks of age through adult life. Animals were castrated at various ages from birth through adult life. Although some studies of the gonadotropin-secretory patterns were longitudinal in nature, most comparisons were cross-sectional. On the basis of our observations, we have arbitrarily grouped the animals into 4 developmental ages: postnatal (less than 7 months), prepubertal or juvenile (7-27 months), pubertal (28-59 months), and adult (greater than or equal to 60 months). In carrying out these studies, blood was withdrawn at 15-min intervals over 24 h without anesthesia using a mobile vest and tether assembly to support an indwelling catheter. GnRH challenge tests were done on 1 or more occasions on all animals. Plasma samples were analyzed for concentrations of FSH and LH by established RIAs and an in vitro bioassay for LH. During the frequent sampling period (24 h for all except postnatal animals), the amplitude of gonadotropin pulses was greatest in adult animals followed by postnatal and pubertal monkeys. During pubertal development, there was a marked increase in the magnitude of gonadotropin pulses, and remarkedly, there was a substantial increase in the LH bioassay: RIA (greater than 5:1) by adult life. GnRH challenge tests of gonadotropins correlated with these observations. Time series analysis was applied to the data for objective statistical characterization of cyclic patterns. Our findings can be summarized: 1) during pubertal maturation there is a change in amplitude but not frequency of gonadotropin pulses, 2) pubertal development of the hypothalamic-pituitary axis advances in the absence of gonadal feedback, and 3) there is a significant increase in the LH bioassay: RIA during pubertal development. We conclude that the castrate monkey is a valuable adjunct to direct clinical investigations of the mechanisms controlling human sexual development.
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Polytetrafluoroethylene (PTFE) was compared to autogenous saphenous vein (ASV) in 133 femoropopliteal and femorotibial or peroneal bypass procedures performed in limb salvage during a 4-year period. PTFE was used as an alternative prosthesis in the absence of a suitable ASV. Sixty-nine femoropopliteal bypasses (FPBPs) were studied--36 with ASV and 33 with PTFE. Sixty-four femorotibial or peroneal bypasses were categorized as femoral distal bypasses (FDBPs)--34 with ASV and 30 with PTFE. With a 3-year clinical follow-up, cumulative function rate (CFR)--patency including thrombectomy--for FPBP with ASV was 65% as compared to 53% for PTFE (P greater than 0.05), whereas the limb salvage rate (LSR) was 75% with ASV and 56% for PTFE (P greater than 0.05). However for FDBP, the GFR was 55% for ASV and 7% for PTFE, whereas the LSR was 55% with ASV and 26% for PTFE. The cumulative patency rate (CPR)--initial thrombosis of a prosthesis as an endpoint--was not significantly (P greater than 0.05) different from CFR, suggesting that thrombectomy with or without distal anastamotic revision does not contribute to patency of the PTFE prosthesis in these limb salvage cases. PTFE was a suitable alternative to ASV for FPBP; however, PTFE is recommended for FDBP in selected cases only.
We examined the effects of acute hemorrhagic pancreatitis on thoracic duct lymph flow and its protein concentration. Thoracic duct lymph flow increased and the protein concentration decreased. These changes in the lymph were associated with steady decreases in arterial pressure and cardiac output and increase in systemic vascular resistance. The results suggest that the increased lymph flow and decreased protein concentration were due to either an ultrafiltration causing a dilution of the lymph protein concentration or to the heterogeneous origin of thoracic duct lymph such that redistribution of blood flow to the essential beds (eg, kidneys) after arterial hypotension altered the lymph flow and its protein concentration. The increase in filtration and the absence of a compensatory "autotransfusion" during arterial hypotension may be a mechanism contributing to circulatory shock in acute pancreatitis.
Adult New Zealand rabbits were injected intrathecally with 200 or 300 mgI/ml of metrizamide, meglumine iocarmate or meglumine iothalamate. They were placed in the Trendelenburg position for 20 min and allowed to survive for 1, 2 or 3 weeks. Sacrifice was by intraarterial perfusion of aldehydes under anesthesia followed by preparation of brain and major venous sinuses for light and electron microscopy. Major findings were subpial edema and inflammatory reaction of superficial brain, leptomeninges, subarachnoid space and arachnoid granulations. They were most severe after iothalamate and milder after metrizamide. The severity decreased with time. It is of significance that severe reactions occurred after 300 mgI/ml concentration of metrizamide.
We used the anesthetized sheep lung lymph preparation to examine the effects of acute hemorrhagic pancreatitis on pulmonary transvascular fluid and protein exchange. Induction of acute pancreatitis by injection of trypsin and sodium taurocholate into the pancreatic duct caused significant increases (p less than 0.05) in lung lymph flow, ratio of lymph to plasma protein concentration (L/P ratio), and transvascular protein clearance. Pulmonary arterial and pulmonary arterial wedge pressures did not change significantly, but pulmonary blood flow decreased (p less than 0.05) and pulmonary vascular resistance increased (p less than 0.05). In contrast to the effects of acute pancreatitis, left atrial hypertension caused increases in lung lymph flow that were associated with decreases in the L/P ratio. Extravascular lung water content was increased after acute pancreatitis by 25% from the value obtained in sham-operated animals in which saline was injected into the pancreatic duct. These findings indicate that acute hemorrhagic pancreatitis causes an increase in pulmonary vascular permeability to proteins. Because pulmonary vascular pressures did not change, the increased permeability may be due to the cellular and humoral factors rather than hemodynamic mechanisms.
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125I labelled Amipaque (metrizamide) was introduced by cisternal puncture into six rabbits and perfused at various pressures. The torcular was exposed, frozen rapidly, and excised intact. Sections of arachnoid proliferations were made from the frozen specimen and either freeze dried or sandwiched directly for autoradiography. Some specimens were freeze dried en bloc prior to sectioning and sandwiching. All sections were exposed for 2-3 weeks at -80 degrees C prior to development of the autoradiographs. On microscopic examinations of the autoradiographs most of the activity was in the tubules or between cells suggesting intercellular passage. Some label was also present within the brain. The significance of this is discussed.