P5408Initiating angiotensin receptor blockade and neprilysin inhibitor (ARNI) in acute heart failure with mechanical support

Introduction

Heart failure still poses great threat to the afflicted patients and enormous burden to our health-care community. Thanks to the ushering of “Angiotensin Receptor Blockade and Neprilysin Inhibitor (ARNI), Entresto®”, we have made further progress by saving one out of 5 of our patients with chronic heart failure in this decade. Current treatment guidelines have suggested the commencement of ARNI in patients with chronic stable heart failure. There is no mention of starting ARNI in the very beginning of the acute phase of heart failure, especially in the patients needing mechanical support. We try to illustrate the clinical picture and implication of ARNI in acute heart failure.

Method

The study was conducted in a 20-bed based cardiovascular intensive care unit of a tertiary-referring center of Taiwan. We enrolled patients of cardiogenic shock, who were put on left ventricular assist device (LVAD) (CentriMag). Those who were dependent on any vasopressors (eg. nor-adrenaline or vasopressin) were excluded. Concurrent usage of inotropes, such as adrenalin, dopamine or dobutamine, would not preclude our application of ARNI and enrollment. The endpoint of this study were: successful weaning of LVAD, cardiovascular death, and the percentage of achieving guideline-suggested target dose of ARNI.

Results

From Jan. 2017 to Jan. 2019., there were 30 patients put on LVAD with CentriMag. Thirteen patients were excluded as their hemodynamics depended on nor-adrenaline. Seventeen patients of 53.1±9.6-year-old were enrolled and 13 of them were successfully rid of LVAD. Four patients succumbed during the support of LVAD, and 3 of them were due to cardiovascular death. Upon enrollment the LVEF was 18±10.1% and NT pro-BNP was 10327±12629 pg/ml. Fifty-three percent of the enrollee could be prescribed with the target dose of 200mg bid Entresto® within 5.1±3.6 days of initiating ARNI, but only 23.5% could tolerate 200mg bid as maintenance. On initiating ARNI, on-going acute kidney injury were taking place in 76.5% of our enrollee, but only 23.5% suffered persistent renal failure, depending on long-term renal replacement therapy. After 27.8±23.0 days of LVAD, the LVEF improved (43.3±23.0%) sufficing the weaning off.

Conclusion

The very beginning of acute heart failure may have the highest surge of neurohormonal bombardment by renin-agiotensin-aldosterone system. Initiating ARNI in this stage, particularly in patients needing mechanical support, may offer some clinical benefit, regardless of initial renal function.

Acknowledgement/Funding

None

Right mini-parasternotomy may be a good minimally invasive alternative to full sternotomy for cardiac valve operations-a propensity-adjusted analysis

AIM

Limited realworld data existed for miniparasternotomy approach with good sample size in Asian cohorts and most previous studies were eclipsed by case heterogeneity. The goal of this study was to compare safety and quality outcomes of cardiac noncoronary valve operations by miniparasternotomy and full sternotomy approaches on riskadjusted basis.

METHODS

From our hospital database, we retrieved the cases of non-coronary valve operations from 1 January 2005 to 31 December 2012, including re-do, emergent, and combined procedures. Estimated EuroScore-II and propensity score for choosing mini-parasternotomy were adjusted for in the regression models on hospital mortality, complications (pneumonia, stroke, sepsis, etc.), and quality parameters (length of stay, ICU time, ventilator time, etc.). Non-complicated cases, defined as survival to discharge, ventilator use not over one week, and intensive care unit stay not over two weeks, were used for quality parameters.

RESULTS

There were 283 miniparasternotomy and 177 full sternotomy cases. EuroScore-II differed significantly (medians 2.1 vs. 4.7, p<0.001). Propensity scores for choosing miniparasternotomy were higher with lower EuroScore-II (OR=0.91 per 1%, p<0.001), aortic regurgitation (OR=2.3, p=0.005), and aortic non-mitral valve disease (OR=3.9, p<0.001). Adjusted for propensity score and EuroScore-II, mini-parasternotomy group had less pneumonia (OR=0.32, p=0.043), less sepsis (OR=0.31, p=0.045), and shorter non-complicated length of stay (coefficient=7.2 (day), p<0.001) than full sternotomy group, whereas Kaplan-Meier survival, non-complicated ICU time, non-complicated ventilator time, and 30-day mortality did not differ significantly.

CONCLUSION

The propensity-adjusted analysis demonstrated encouraging safety and quality outcomes for mini-parasternotomy valve operation in carefully selected patients.

The influence of gender difference on the outcomes of infrainguinal bypass for critical limb ischaemia in Chinese patients

PURPOSE

to investigate the influence of gender difference on the outcomes of infrainguinal bypass operations performed in Chinese patients with critical limb ischaemia.

METHODS

we prospectively studied the results of 191 consecutive infrainguinal bypass operations (98 men, 93 women) for critical lower limb ischaemia in Chinese patients.

RESULTS

the women were older than men (median 75 vs 70 years, p=0.001) and cigarette smoking was commoner in men (83% vs 37% p<0.001). The calibre of run-off arteries at the level of distal anastomosis was smaller in women (median 2.5 mm vs 2.0 mm, p=0.03). The 30-day mortality was 3% (five men vs one woman, p=0.09) and early graft failure occurred in 19 patients (12 women vs seven men, p=0.28). At 3 months limb loss occurred in 16 (10 women vs six men, p=0.35) patients. Survival (38% vs 60% at 4 years, p=0.12) was similar in men and women. However, women suffered from poorer primary (33% vs 49% at 3 years, p=0.03) secondary graft patency rates (35% vs 64% at 3 years, p=0.02) than men. Limb survival rate in two groups (75% vs 85% at 4 years, p=0.18) was comparable.

CONCLUSION

following infrainguinal bypass for critical limb ischaemia, early results were similar in both gender groups. In the long-term, women patients suffered from significantly higher graft failure rate. However, their long-term survival and limb salvage rate remained comparable to those of men.

Spontaneous intramural hematoma of stomach

BACKGROUND

Intramural hematoma occurs uncommonly in the gastrointestinal tract and very rarely in the stomach. In case of a spontaneous gastric hematoma, the few previously reported patients all had certain predisposing factors. However, truly spontaneous intramural hematoma of the stomach without an identifiable cause has not been reported before.

METHOD

Emergency total gastrectomy was performed in a 49-year-old man with such pathology and the diagnosis was made postoperatively.

RESULTS

The patient required further laparotomy on day 10 for drainage and debridement of a subphrenic abscess. He recovered uneventfully from the second operation. After an extensive pathological search, no predisposing factors could be found. The patient remains in good health 18 months after the operations.

CONCLUSION

Spontaneous intramural gastric hematoma is extremely rare. But even rarer is when predisposing conditions or lesions are absent.

Selective estrogen receptor modulators and postmenopausal health

SERMs are a class of drugs with mixed estrogen agonist/antagonist effects that have great potential at targeting changes seen in the postmenopausal period. Raloxifene is effective in preventing bone loss and may prevent fractures in postmenopausal osteoporosis. It induces changes in lipoprotein concentrations that should be cardioprotective. It has no stimulatory effect on the uterus and is well tolerated. Raloxifene is an attractive alternative to HRT in preventing postmenopausal bone loss, especially for women that are more concerned about the risk of breast cancer or vaginal bleeding. Unanswered questions include raloxifene's effect on fracture incidence, cardiac events, and dementia; long-term safety data are also needed. Its potential role in the primary prevention of breast cancer also needs large, long-term studies. Tamoxifen has been used traditionally as adjuvant therapy for breast cancer, but new data indicate that it is effective in the primary prevention of breast cancer in women at increased risk. Its effects on bone and lipoproteins are attractive complementary effects when used in the subset of women at increased risk for breast cancer. New generations of SERMs are being developed that may have more potent estrogen agonist effects on bone and cardiovascular disease, or more potent antiestrogen effects, especially at the breast. There will likely be a selection of SERMs available, and the choice of SERM for a woman will be tailored to her specific issues and risk profile.

Correlation of estradiol, parathyroid hormone, interleukin-6, and soluble interleukin-6 receptor during the normal menstrual cycle

Rodent models suggest that estradiol deficiency promotes bone loss through increasing interleukin-6 (IL-6) activity. However, it is controversial as to whether these findings are applicable to humans. To evaluate estradiol-mediated modulation of IL-6 activity in relation to bone metabolism in humans, we measured serum IL-6, soluble interleukin-6 receptor (sIL-6R), estradiol (E2), progesterone, luteinizing hormone, follicle-stimulating hormone, intact parathyroid hormone (PTH), serum and urine Ca, and bone biochemical markers (serum bone-specific alkaline phosphatase, osteocalcin, and serum and urine deoxypyridinoline [Dpd]) across one menstrual cycle for 211 women. Neither IL-6 nor sIL-6R levels differed between the follicular phase (FP) and the luteal phases (LP). However, IL-6 was negatively correlated with E2 during the FP (p =0.003). Furthermore, IL-6 correlated positively with serum Ca over the entire cycle (p = 0.0091. Serum Ca correlated positively with serum (p = 0.040) and urine (p = 0.006) Dpd. PTH was significantly higher during the FP than in the LP (p = 0.004). PTH was negatively related to E2 (p = 0.002), serum Ca (p < 0.001), and urine Ca (p = 0.036), whereas it was positively correlated with IL-6 (p = 0.027). These data demonstrate that IL-6 and PTH fluctuate with E2, and serum II-6 is associated with PTH levels during the menstrual cycle. However, the role of 11-6 in bone remodeling during the normal menstrual cycle remains to be determined.

Carnitine and dehydroepiandrosterone sulfate induce protein synthesis in porcine primary osteoblast-like cells

Age-related bone loss eventually leads to osteopenia in men and women. The etiology of age-related bone loss is currently unknown; however, decreased osteoblast activity contributes to this phenomenon. In turn, osteoblast proliferation and function is dependent on energy production, thus the loss of energy production that occurs with age may account for the deficient osteoblast activity. Carnitine and dehydroepiandrosterone-sulfate (DHEAS), both of which decline with age, promote energy production through fatty acid metabolism. Thus, we hypothesized that carnitine and DHEAS would increase osteoblast activity in vitro. Accordingly, we measured the effect of carnitine and DHEAS on palmitic acid oxidation as a measure of energy production, and alkaline phosphatase (ALP) activity and collagen type I (COL) as indices of osteoblast function in primary porcine osteoblast-like cell cultures. Carnitine (10(-3) and 10(-1) M) but not DHEAS (10(-9), 10(-8), and 10(-7) M) increased carnitine levels within the cells. Carnitine alone and in combination with DHEAS increased palmitic acid oxidation. Both carnitine and DHEAS alone and in an additive fashion increased ALP activity and COL levels. These results demonstrate that in osteoblast-like cells in vitro, energy production can be increased by carnitine and osteoblast protein production can be increased by both carnitine and DHEAS. These data suggest that carnitine and DHEAS supplementation in the elderly may stimulate osteoblast activity and decrease age-related bone loss.

Changes in bone resorption during the menstrual cycle

To determine if the cyclic changes of female sex hormones during the menstrual cycle are related to changes in bone formation and resorption, we measured serum bone-specific alkaline phosphatase (BAP) and osteocalcin (OC) and bone resorption markers, serum and urine deoxypyridinoline (Dpyr), three times per week during one menstrual cycle in 20 healthy premenopausal women. Serum estradiol (E2) and progesterone (P) showed characteristic cyclic fluctuations. Serum Dpyr was higher during the follicular phase (FP) than in the luteal phase (p = 0.027). Serum BAP, OC, and urine Dpyr levels did not change substantially across the cycle. Serum Dpyr correlated negatively with serum E2 values measured 6 (p = 0.011) and 8 (p = 0.001) days earlier and with P measured concurrently (p = 0.033) 2 (p = 0.002), 4 (p = 0.003), and 6 (p = 0.014) days earlier. BAP correlated negatively with E2 measured 6 days earlier (p = 0.006). We found no statistically significant correlations of E2 or P with OC or urine Dpyr within women over their cycles. BAP was positively correlated with concurrent serum Dpyr (p = 0.015) during the menstrual cycle. Serum OC levels correlated inversely with age (rs = -0.48, p = 0.036). Women with higher mean urine Dpyr levels had higher mean serum OC levels (rs = 0.49, p = 0.033) and showed a trend toward lower hip bone mineral density (rs = -0.40, p = 0.078). We conclude that the low level of E2 and/or P observed during the FP of the normal menstrual cycle is associated with increased bone resorption. These relationships suggest that normal women experience monthly episodes of increased bone resorption from menarche to menopause.

Correlation of serum L-carnitine and dehydro-epiandrosterone sulphate levels with age and sex in healthy adults

OBJECTIVES

L-carnitine and dehydro-epiandrosterone (DHEA) independently promote mitochondrial energy metabolism. We therefore wondered if an age-related deficiency of L-carnitine or DHEA may account for the declining energy metabolism associated with age.

METHODS

we evaluated serum levels of L-carnitine and the sulphated derivative of DHEA (DHEAS) in cross-sectional study of 216 healthy adults, aged 20-95.

RESULTS

serum DHEAS levels declined, while total carnitine levels increased with age (P < 0.0001). Total and free carnitine and DHEAS levels were lower in women than men (P < 0.0001). Esterified/free (E/F) carnitine (inversely related to carnitine availability) increased with age in both sexes (P=0.012).

CONCLUSION

reduced carnitine availability correlates with the age-related decline of DHEAS levels. These results are consistent with the hypothesis that decreased energy metabolism with age relates to DHEAS levels and carnitine availability.

Arterial lesions in severe lower limb ischaemia: a prospective study of 100 consecutive ischaemic limbs in a Hong Kong Chinese population

BACKGROUND

The pattern and distribution of arterial lesions in a local Chinese population were studied to assess the feasibility of reconstruction and the possibility of avoiding major amputation of ischaemic limbs.

METHOD

Between March 1995 and August 1997, 90 consecutive patients with 100 severely ischaemic lower limbs and their arteriograms were analysed. There were 48 female and 42 male patients with a mean age of 72 years. All the patients were in fair general health, did not have foot pulses and were willing to undergo major arterial reconstruction. Ten patients had bilateral limb ischaemia and 94 of the ischaemic limbs were affected by rest pain with or without ulcer and/or gangrene. The remaining six patients had debilitating claudication. These lesions were classified into low-grade (less than 50% stenosis), high-grade (50-90% stenosis) and critical (> 90% stenosis to occlusion).

RESULTS

Critically stenotic or occlusive lesions were present in 16% of aorto-iliac segments; 76% of femoropopliteal arteries; and 82% of trifurcation and infrapopliteal segments. In at least 27 patients one of the two main foot arteries was also severely diseased. The present analysis suggested that 79 of these ischaemic limbs had reconstructable lesions. Sixteen were not suitable for intervention and in five patients the reconstructability was uncertain radiologically.

CONCLUSION

Contrary to local belief, the majority of patients in the Chinese community with severe lower limb ischaemia without foot pulses would have technically reconstructable arterial lesions and could benefit from a revascularization procedure.

A multidisciplinary approach to salvage the 'unsalvageable' foot

Extensive tissue loss in a weight-bearing area of the foot almost invariably heralds limb loss. We report on a 74-year-old man with diabetes mellitus who had an ischaemic foot that was affected by prolonged pressure, which resulted in a necrotic heel. After two sessions of debridement, the calcaneum became exposed. Amputation was initially suggested but was refused by the patient. The foot was subsequently salvaged by staged operations. The first operation was a femoro-anterior tibial bypass using an autogenous saphenous vein to revascularise the foot. This was followed by debridement and attachment of a free subscapular flap to cover the defect 2 weeks later by a plastic surgeon. After 85 days of rehabilitation by physiotherapy and education of foot care by a podiatrist, the patient was discharged home and was able to walk with a walking-stick. This multidisciplinary approach

Laparoscopic resection of a primary retroperitoneal mucinous cystadenoma: report of a case

Primary retroperitoneal mucinous cystic tumors are extremely rare, and although their histogenesis is still uncertain, several theories have been proposed. Traditionally, transabdominal laparotomy and enucleation of the cyst is the treatment of choice and laparoscopic resection has not previously been reported. This paper presents the case of a 48-year-old woman in whom a primary retroperitoneal cystic mass, 15 x 13 x 9 cm in size, was successfully resected through the laparoscope. Pathological examination revealed a mucinous cystadenoma with borderline malignancy. The patient had a prompt recovery and there was no evidence of recurrence at her 8-month follow-up. However, the prevention of cystic fluid spillage during laparoscopic manipulation is important, especially when the pathology of the retroperitoneal cyst is unclear.

Arterial reconstruction for lower limb ischaemia in Hong Kong Chinese

BACKGROUND

Lower limb ischaemia due to peripheral arterial disease is uncommon in Chinese people, and few arterial bypass operations have been performed. The management of a consecutive series of patients who were admitted to our department with severe lower limb ischaemis between March 1990 and October 1996 is reported here.

METHODS

A total of 91 primary arterial bypass operations were performed for 83 patients (eight patients had bilateral, or two procedures). Of these, 84 operations were for foot salvage and seven operations were for debilitating claudication. There were 80 infra-inguinal bypasses, 10 of which required additional femoro-femoral crossover grafts to improve in-flow. The remaining 11 bypass procedures were performed for aorto-iliac occlusion, which included aortobifemoral bypass (5), axillobifemoral bypass (3) and cross-femoral bypass (3) grafts. There were 46 male and 37 female patients, with a median age of 70 years (36-94).

RESULTS

Six patients died (6.6%) postoperatively, all of whom were in the foot salvage group. The overall cumulative foot salvage rate and graft patency was 84 and 56%, respectively, at 5 years.

CONCLUSIONS

These results justified the use of the same aggressive approach that was adopted in Western countries for the treatment of peripheral arterial disease, which seemed to be an emerging problem in Hong Kong.

Effect of dehydroepiandrosterone sulfate on carnitine acetyl transferase activity and L-carnitine levels in oophorectomized rats

Alteration in energy metabolism of postmenopausal women might be related to the reduction of dehydroepiandrosterone sulfate (DHEAS). DHEA and DHEAS decline with age, leveling at their nadir near menopause. DHEA and DHEAS modulate fatty acid metabolism by regulating carnitine acyltransferases and CoA. The purpose of this study was to determine whether dietary supplementation with DHEAS would also increase tissue L-carnitine levels, carnitine acetyltransferase (CAT) activity and mitochondrial respiration in oophorectomized rats. Plasma L-carnitine levels rose following oophorectomy in all groups (P < 0.0001). Supplementation with DHEAS was not associated with further elevation of plasma L-carnitine levels, but with increased hepatic total and free L-carnitine (P = 0.021 and P < 0.0001, respectively) and cardiac total L-carnitine concentrations (P = 0.045). In addition, DHEAS supplementation increased both hepatic and cardiac CAT activities (P < 0.0001 and P = 0.05 respectively). CAT activity positively correlated with the total and free carnitine levels in both liver and heart (r = 0.764, r = 0.785 and r = 0.700, r = 0.519, respectively). Liver mitochondrial respiratory control ratio, ADP:O ratio and oxygen uptake were similar in both control and supplemented groups. These results demonstrate that in oophorectomized rats, dietary DHEAS supplementation increases the liver and heart L-carnitine levels and CAT activities. In conclusion, DHEAS may modulate L-carnitine level and CAT activity in estrogen deficient rats. The potential role of DHEAS in the regulation of fatty acid oxidation in postmenopausal women is worthy of investigation.

Quad-band excitation for low bit rate speech coding

The excitation parameters of a multiband excitation model for speech production consist of a pitch period and a series of voiced/unvoiced (v/uv) decisions for a number of fixed frequency bands around the harmonics of the fundamental. In this paper, it is shown that, at most, four v/uv variable-length nonoverlapping frequency bands spanning over the telephone bandwidth are adequate to represent the excitation spectrum that provides an improved modeling of mixed voicing and noisy speech. A quad-band excitation (QBE) method is presented which generates excitation source for a linear prediction vocoder for low bit rate transmission of speech signal and the DRT scores validate the potential of the method.

Single-layer continuous anastomosis in gastrointestinal surgery: a prospective audit

BACKGROUND

Single-layer intestinal anastomoses have been constructed conventionally using an interrupted suture technique. It is however, increasingly popular to perform such anastomosis using a continuous suture.

METHODS

One hundred and eighty consecutive patients with 254 continuous single-layer anastomoses performed over a 4 year period were included in the study. Sixty-one patients underwent oesophagectomy, oesophageal bypass or gastrectomy, 32 underwent biliary bypass, hepatic, biliary or pancreatic resection and 88 had colorectal operations. The median age was 67 years.

RESULTS

There were 254 anastomoses of which four leaked (1.6%). Fifteen patients (8.3%) died in hospital.

CONCLUSION

These results show that the single-layer continuous suture technique is safe in gastrointestinal anastomoses.

Simple configuration to generate short bursts of picosecond optical pulses

We have developed an efficient method of generating short bursts of picosecond optical pulses. The multiplying stage consists of simple optical elements, including 50/50 beam splitters and a 100% reflecting mirror. Time delay between the pulses can be adjusted by changing the incident angle of the beam or the separation of the splitters. The multiplying scheme has been successfully applied to the output of a cw mode-locked Nd:YAG laser at 82 MHz. Multiplication of beam pulses up to a factor of 8 was demonstrated. This technique promises to increase the repetition rate of laser pulses up to hundreds of gigahertz.

Immunologically mediated aplastic anemia in mice: evidence of hematopoietic stromal injury and injury to hematopoietic stem cells

Immunologically mediated aplastic anemia (AA) results when lymph node cells (LNC) from C3H/He mice are injected intravenously (i.v.) into H-2 identical CBA/J mice previously given 600 cGy sublethal total-body gamma irradiation (TBI). Previously, we showed that T lymphocytes injure pluripotent hematopoietic stem cells and cause severe pancytopenia and death in 80 to 100% of mice within 3 to 4 weeks, with changes in the bone marrow suggesting stromal injury. The following models were used to study the stroma: (1) Transplantation of femurs from AA mice into normal syngeneic CBA/J mice. After 6 weeks, colony-forming unit-spleen (CFU-S) levels in the femur implants were measured in both AA and control mice (600 cGy TBI only). (2) Development of Dexter long-term bone marrow cultures from AA and control mice, which were used to support hematopoietic bone marrow cells (colony-forming units-granulocyte/macrophage [CFU-GM]) from normal mice. (3) Cellulose ester membranes (CEM) were coated with hematopoietic stroma from AA and control mice and then implanted intraperitoneally (i.p.) into syngeneic CBA/J mice. Six months later, the CEM were removed and analyzed for the presence of trilineal hematopoiesis and bone. Injury to the hematopoietic stroma was documented by the following: (1) Femurs from AA mice had a decreased number of CFU-S compared to controls; (2) Dexter cultures from AA mice formed abnormal stromal layers with a decreased capacity to support CFU-GM from normal donor mice; and (3) CEM coated with stromal cells from AA mice had a decreased capacity to support trilineal hematopoiesis and bone compared to CEM coated with marrow stroma from control mice.

Comparison of prophylactic ampicillin/sulbactam with gentamicin and metronidazole in elective colorectal surgery: a randomized clinical study

A randomized control clinical study was conducted to compare the effectiveness of prophylactic ampicillin/sulbactam in preventing wound infection after elective colorectal surgery with a combination of gentamicin and metronidazole. Over a 2-year period, 143 patients were recruited, but 15 patients were subsequently excluded due to the use of additional antibiotics for the treatment of pulmonary or urinary infection or early postoperative death without wound infection. Of the 128 evaluable patients, six of the 63 patients (9.5%) in the ampicillin/sulbactam group and seven of the 65 patients (10.7%) in the gentamicin and metronidazole group developed wound infection. We conclude that prophylactic ampicillin/sulbactam is effective in reducing the risk of wound infection following colorectal surgery.

Inhibitor of granulocyte-macrophage colony formation in plasma of mice rendered aplastic by allogeneic lymph node cells

Sublethally irradiated CBA/J mice injected with lymph node cells (LNC) of C3H/He mice exhibit aplastic anemia within 3 weeks. Aplastic anemia plasma (AAP) from these mice was found to inhibit granulocyte-macrophage colony (GM-CFU) formation. This inhibitory action was not strain specific and was not generated in donor:host combination involving other strains. AAP also inhibited the formation of colonies derived from leukemic cell lines. Though this activity inhibited GM-CFU, it did not affect erythroid colony formation. Two experiments were performed to examine the mechanism of inhibition. Superoptimal concentrations of recombinant mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) did not reverse AAP-induced inhibition of colony formation. Bone marrow cells preincubated with AAP for 24 h and washed were unchanged in their ability to form GM-CFU colonies. Thus, the inhibitory activity acted neither as a competitive nor a cytotoxic agent. Interferons and certain prostaglandins, known to inhibit colony formation, were not found in active concentrations in AAP. The inhibitory activity of AAP was heat stable, nondialyzable, inextractable with chloroform, precipitable with 50% ammonium sulfate, and had a molecular weight of 100,000 daltons. In contrast, control plasma from mice given only sublethal irradiation and injected with saline had significantly less inhibitory activity, which was not heat stable and was extractable with chloroform. Thus, LNC in certain host mouse strains generate a plasma activity that can inhibit the formation of normal and leukemic GM-CFU colonies.

Immunologically mediated aplastic anemia in mice: effects of varying the source and composition of donor cells

Experimental aplastic anemia (EAA) can be induced in CBA/J mice when they are sublethally irradiated and injected with lymph node cells (LNC) from C3H/He mice. Mice injected with LNC die of severe pancytopenia and marrow aplasia. In the present study, cells from other anatomical locations and subsets of LNC were examined for their ability to induce and to modulate EAA. Of peritoneal, splenic, and thymic cells, only cells from the thymus had EAA activity. C3H/He bone marrow cells did not induce any adverse effects in sublethally or lethally irradiated CBA/J mice. LNC, when depleted of B or phagocytic cells, retained EAA activity. In contrast, LNC depleted of T cells had significantly less EAA activity. Furthermore, when T cells of LNC were separated into peanut agglutinin (PNA)-receptor-positive and negative fractions, only the PNA- cells were able to induce EAA. EAA activity was lost when LNC were irradiated (1000 rad). The inability of splenic or bone marrow cells to induce EAA could have been due to the presence of cells that suppressed EAA activity. When splenic or bone marrow cells were coinjected with LNC, EAA was not induced. Coinjected irradiated splenic cells, but not bone marrow cells, were still able to inhibit EAA activity. Bone marrow cells seemed to inhibit EAA by replacing stem cells that were lost during the EAA process. On the other hand, splenic cells appeared to suppress EAA activity of LNC. Thus, radiosensitive PNA- T cells of lymph nodes or thymus were capable of inducing EAA, and their activity could be modulated by radioresistant splenic cells.

The separation of cytotoxic human peripheral blood monocytes into high and low phagocytic subsets by centrifugal elutriation

Mononuclear cells (4 X 10(8) in a 5-ml volume) were loaded onto a Beckman JE-6B elutriator rotor spinning at 2,000 +/- 10 rpm with a flow rate of 10.0 ml/min. After lymphocytes were removed at flow rates between 10 and 11 ml/min with 500 ml of buffer, the flow rate was increased by 0.5 ml/min/fraction to collect 100-ml fractions. Highly enriched monocytes as judged by nonspecific esterase staining and morphology (70-95%) were found in each of eight fractions collected with flow rates between 11.5 to 15.0 ml/min. When stimulated with phorbol myristic acetate, these fractions mediated equivalent levels of cytotoxicity against 51Cr-labeled Chang liver cell line. Similarly, each monocyte-containing fraction was found to mediate the same level of cytotoxicity against antibody-sensitized 51Cr-labeled Chang liver cells. In contrast, cytotoxicity against the natural killer cell-sensitive K-562 cell line was found in only those fractions that contained a high percentage of lymphocytes. The fractions that were enriched in monocytes were found to differ in their ability to ingest latex. Those monocyte fractions that were collected between 11.0-12.0 ml/min consisted primarily of low numbers of latex-ingesting monocytes (less than 30%). Those monocyte fractions that were collected between 12.5 and 15.0 ml/min consisted primarily of latex-ingesting monocytes (50-70%). These data show that cytotoxic monocytes can be separated by centrifugal elutriation into at least two subsets that can be distinguished by their phagocytic activity.

Susceptibility of Oncomelania hupensis subspecies to infection with geographic strains of Schistosoma japonicum

Subspecies of Oncomelania hupensis were exposed to infection with zoophilic and anthropophilic strains of Schistosoma japonicum. The snails were Philippine O. h. quadrasi from the islands of Bohol, Leyte and Mindanao, O. h. formosana from Changhua and Ilan, and O. h. chiui from Taiwan, O. h. hupensis from China, O. h. nosophora from Japan and O. h. lindoensis from Indonesia. Anthropophilic strains of S. japonicum were from Bohol and Leyte in the Philippines, China, Japan and Indonesia. The zoophilic strains were from Changhua and Ilan, Taiwan. All geographic strains of the parasite developed exceptionally well and produced cercariae in 32-50% of O. h. chiui and 5-43% of the natural snail hosts. Development in other subspecies of snails with geographic strains of the parasite were variable. Only a few O. h. formosana (Changhua) could be infected with the parasites from other geographic areas and only one O. h. quadrasi each from Mindanao became infected with the Bohol and Changhua strains of S. japonicum.

Chronic intratumoral chemotherapy of a rat tumor with cisplatin and fluorouracil

In order to demonstrate the feasibility and efficacy of intratumoral chemotherapy, brain tumors in rats were treated by direct infusion of cisplatin or fluorouracil. Each animal was initially implanted in the midline cerebellum with a chronic stainless-steel cannula, and 2 weeks later 1 X 10(5) 9L cells were injected through the cannula. 8 days after tumor cell transplantation, a small implantable pump containing drug, or saline as a control, was connected up to the same cannula, and the solution was pumped into the tumor region for 7 days. The results showed that both drugs produced statistically significant increases in survival as compared to the controls.

The immunological response of Wistar rats to the intracranially implanted C-6 glioma cell line

The immune response of Wistar rats to the intracranial inoculum of 1 X 10(5) C-6 glioma cells was evaluated. The growth of these cells disrupted the blood-brain barrier by day 9. The rats with the implanted tumor cells died between three to four weeks following injection. No significant cell-mediated cytotoxicity against 51Cr labelled C-6 cells was seen in the short term (4 hours) cytotoxicity assay with spleen cells obtained from glioma-bearing rats at any stage of tumor growth. In the long term (18 hours) cytotoxicity assay, significant activity was detected using whole, adherent and nonadherent spleen cells from glioma-bearing rats at every assessment point during the growth of the tumor, but this cytotoxicity was also seen in normal rat splenocytes. The lack of cell mediated cytotoxicity above normal values was not due to a generalized immunosuppression since splenocytes from glioma bearers were found to have responses to Con A comparable to normal controls. However, normal or glioma-bearer splenocytes showed augmented cytotoxicity in the presence of serum obtained from rats bearing a glioma tumor starting by day 13 of tumor growth and rising in cytotoxic activity until death. This activity was not seen with normal serum. The glioma-bearer serum, though not cytotoxic to the C-6 cells alone, became cytotoxic with the addition of rabbit complement. These data indicate that the growth of intracranially implanted glioma cells in rats elicits primarily a humoral cytotoxic immunity without a significant cell-mediated immunity. This humoral immunity develops after the breakdown of the blood-brain barrier.

Heterogeneity of cytolytic and suppressor clones of alloactivated cells generated from soft agar colonies

Long-term cell cultures (or clones) were developed from soft agar colonies of lymphocytes alloactivated in mixed leukocyte culture reaction (MLR). Two types of colonies were identified: upper colonies that grew on the agar surface, and lower colonies found within the agar layer. Virtually all cytolytic clones originated exclusively from the upper colonies. Two groups of cytolytic clones could be distinguished, one with strong and the other with weak proliferation upon restimulation. Upper clones were capable of inhibiting primary MLR proliferation and this appeared to be related to their cytolytic effect on the stimulator. Many noncytolytic lower clones were found to suppress primary MLR cultures. Considerable heterogeneity was apparent from differences in the magnitude of suppression and the ability of the clones themselves to undergo stimulator-induced proliferation. Kinetic studies of MLR suppression were conducted to further analyze this heterogeneity. Two major kinetic patterns were observed. One showed a biphasic proliferation pattern of the MLR + clone culture. The first peak appeared to reflect an enhanced proliferation of the clone. The second phase seemed to represent diminished proliferation of the MLR responder. This type of suppression may be related to T cell growth factor depletion from MLR by the proliferating clone. The other kinetic pattern showed a consistently low proliferation of the MLR + clone culture throughout the 8-day assay period. Subsequent testing of these suppressor clones in third-party MLR cultures suggested that the specificity of suppression was unrelated to HLA-DR, MB, MT, and SB.

Functional differences between cells from MLR colonies grown in soft agar cultures

This report describes a method of growing soft agar colonies of human T lymphocytes activated in the MLR. Two types of colonies were demonstrated: lower colonies grew within the agar layer, and upper colonies grew on the surface of the agar layer. Three days of priming the lymphocytes in the MLR and the use of supernatants of day-3 MLR cultures to provide T cell colony growth factor were necessary for optimal colony formation. Lymphocytes obtained from colonies were grown in long-term (2 to 4 weeks) cultures to generate sufficient numbers of cells to be tested in different functional assays. Cells from both types of colonies exhibited PLT activity. Upper colony cells showed considerably higher CML activity than lower colony cells (mean percent cytotoxicity 37 +/- 5 vs 6 +/- 3). Cells from both types of colonies contained radiosensitive suppressor cell activity that inhibited the primary MLR. The suppressor cell effect of lower colony cells was specific for the original stimulator, but upper colony cells displayed nonspecific suppressive effects. For both types of colony cells, it appeared that suppressive effects were unrelated to the CML activity of these cells. These data suggest that the soft agar colony assay offers a promising approach to separate subpopulations of lymphocytes activated in the MLR.

Functional differences between cells from MLR colonies grown in soft agar cultures

This report describes a method of growing soft agar colonies of human T lymphocytes activated in the MLR. Two types of colonies were demonstrated: lower colonies grew within the agar layer, and upper colonies grew on the surface of the agar layer. Three days of priming the lymphocytes in the MLR and the use of supernatants of day-3 MLR cultures to provide T cell colony growth factor were necessary for optimal colony formation. Lymphocytes obtained from colonies were grown in long-term (2 to 4 weeks) cultures to generate sufficient numbers of cells to be tested in different functional assays. Cells from both types of colonies exhibited PLT activity. Upper colony cells showed considerably higher CML activity than lower colony cells (mean percent cytotoxicity 37 +/- 5 vs 6 +/- 3). Cells from both types of colonies contained radiosensitive suppressor cell activity that inhibited the primary MLR. The suppressor cell effect of lower colony cells was specific for the original stimulator, but upper colony cells displayed nonspecific suppressive effects. For both types of colony cells, it appeared that suppressive effects were unrelated to the CML activity of these cells. These data suggest that the soft agar colony assay offers a promising approach to separate subpopulations of lymphocytes activated in the MLR.

Interactions of alpha1-acid glycoprotein with the immune system. I. Purification and effects upon lymphocyte responsiveness

Alpha1-acid glycoprotein (AAG) is a constituent of normal serum which is elevated in concentration in the acute phase of inflammation; its physical and chemical properties have been defined but its biological function is uncertain. In the present study, the effect of AAG on the proliferative response of lymphocytes to several different stimuli was determined. For this purpose AAG was prepared by precipitation of human ascites fluid with sulphosalicylic acid and passage of the supernate through SP-Sephadex; the eluted protein migrated as a single band during immunoelectrophoresis, polyacrylamide gel electrophoresis and chromatography on Bio-Gel-A-1-5 m in 6 M guanidine HCl. This AAG was found to markedly inhibit the proliferative response of human peripheral blood lymphocytes to PHA; it also inhibited blastogenesis induced by Con A and PWM, but to a lesser extent. AAG was not cytotoxic to lymphocytes, and its inhibitory effects were reversed at higher mitogen concentrations. Lymphocytes preincubated with AAG remained less reactive to PHA indicating that, although AAG appeared to react with PHA, its effect was directed predominantly to the cell. Further, AAG markedly inhibited the mixed lymphocyte response, and this effect was directed to the responder cells. Thus, AAG is another acute phase reactant with the ability to modulate lymphocyte responsiveness.