[On-pump total arterial revascularization in coronary artery disease patients with left ventricular dysfunction: a multi-center retrospective study].

Objective: To evaluate the clinical outcomes of on-pump total arterial revascularization with bilateral radial artery (BRA) and left internal mammary artery (LIMA) as conduits in coronary artery bypass grafting (CABG) patients with left ventricular dysfunction (LVD). Methods: All the perioperative medical records and follow-up results of coronary artery disease patients with left ventricular ejection fraction (LVEF) ≤ 40% undergoing CABG from 24 heart centers of 15 provinces and autonomous regions in China between July 2015 and December 2019 were retrospectively analyzed. Results: A total of 87 consecutive patients (55 males and 32 females) underwent on-pump CABG with BRA and LIMA, with a mean age of (57.5±9.1) years old. There were 22 patients complicated with primary hypertension, 12 with diabetes mellitus, 8 with peripheral vascular disease, 7 with chronic obstructive lung disease, 12 with mild renal injury and 3 with partial aortic calcification. There were 43 cases with in-stent stenosis, and 21 had left main disease. The mean LVEF and left ventricular end-diastolic diameter (LVEDD) was (35.5±7.3)% and (65.5±2.6) mm, respectively. The mean graft number, aortic cross-clamp time and cardiopulmonary bypass duration was 3.2±0.9, (90.5±22.7) min and (113.4±19.2) min, respectively. There were 32 mitral and 9 aortic valve replacements, and 5 tricuspid annuloplasties. Prophylactic intra-aortic balloon pumps were implanted in 27 patients. There were 2 operative deaths from acute heart failure. After surgery, there were 15 cases of atrial fibrillation, 1 case of acute kidney injury, 1 case of acute myocardial infarction, and 1 cases of stroke. All the patients fulfilled the follow-up, with a mean time of (39.5±7.7) months. At 3 months after surgery, LVEDD was decreased and LVEF was improved significantly compared with pre-operative indicators [(53.0±1.5) mm vs (65.5±2.6) mm, t=9.51 P=0.02; (45.2±3.3)% vs (35.5±7.3)%, t=13.79, P=0.001]. No major cardiac events were reported during the follow-up. At (30.5±7.4) months after surgery, 62.4% of patients (53/85) underwent coronary CT angiography examination, and the results indicated that the graft patency was 98.8%, with only one case of RA occlusion occurred. Conclusion: In selected patients of LVD, on-pump total arterial revascularization with BRA and LIMA conduits was proved to be safe and effective.

[Mid-term multi-center outcomes of bilateral radial artery as conduits in coronary artery bypass grafting].

Objective: To evaluate the mid-term outcomes of bilateral radial artery (BRA) grafts in coronary artery bypass grafting (CABG). Methods: All perioperative medical records and follow-up results of CABG with BRA grafts in multi-centers of China were analyzed retrospectively. Results: A total of 211 patients (170 males and 41 females) underwent CABG grafting with BRA conduits between August 2013 and September 2018, with a mean age of (56.5±9.7) years old (rang 41 to 73 years). There were 161 cases of triple-vessel disease and 50 cases of two-vessel disease. Ninety patients had diabetes mellitus (DM), 35 patients with peripheral vascular disease, 4 patients with chronic obstructive pulmonary disease and 11 with heart valve disease. Two patients underwent off-pump CABG and 209 patients accepted on-pump CABG with commitment valve surgery. There were 210 cases of total arterial revascularization and 161 cases using left thoracic artery conduits, with a graft number of 2-4 (2.7±0.9). No operation-related death occurred, atrial fibrillation happened in 12 patients, hemothorax in 7 cases, and forearm hematoma in one case, hypoxemia in 13 cases and pneumonia in one case. The duration of mechanical ventilation was (8.3±4.7) hours and the mean hospital length of stay was (7.1±2.9) days. Follow-up was completed in 191 patients (90.52%) with a duration of 3-59 (35.5±9.3) months. The mean left ventricular ejection fraction at 3 months after operation was significantly improved, compared to that of the pre-operation (61.0%±7.2% vs 47.1%±5.3%, P=0.017). All patients survived, except that one died from brain injury. No major cardiac events occurred, with a cumulative survival rate of 100% at 1 year and 99.53% at 3 year after operation, respectively. It was showed in coronary CT angiography (CTA) examination that all grafts in 132 patients were patent at the mean follow-up duration of (21.5±6.4) months. Conclusions: BRA grafts as arterial conduit in CABG are proved to be safe, easy for total arterial revascularization and have good mid-term clinical results.

Analysis of segmental phosphate absorption in intact rats. A compartmental analysis approach.

Available information supports the dominance of the proximal intestine in inorganic phosphate (Pi) absorption. However, there is no strategy for analyzing segmental Pi absorption from a spontaneously propelled meal in an intact animal. We propose a solution using compartmental analysis. After intragastric administration of a 32P-labeled Pi liquid meal containing a nonabsorbable marker, [14C]polyethylene glycol (PEG), rats were killed at 2, 10, 20, 30, 60, 120, and 240 min. The gastrointestinal tract was removed and divided into seven segments, from which 32P and [14C]PEG were recovered. Data was expressed as a percentage of the dose fed, i.e., (32P[in segment] divided by 32P[fed]) and [14C]PEG[in segment] divided by [14C]PEG[fed]), respectively. A compartmental model was constructed and the rate constants for intersegmental transit and segmental absorption were estimated. The "goodness of fit" between the simulated model and the actual data indicates the estimated rate constants reflect in vivo events. The duodenum, with the highest transit and absorption rates, accounted for a third of the total absorption. However, the terminal ileum, with a lower absorption rate but a longer transit time, absorbed an equal amount of Pi. This approach allows the analysis of the mechanism and the regulation of Pi absorption under more authentic in vivo conditions.

A locus for spondylocarpotarsal synostosis syndrome at chromosome 3p14.

Spondylocarpotarsal synostosis syndrome is a rare autosomal recessive disorder characterised by vertebral fusions, frequently manifesting as an unsegmented vertebral bar, as well as fusions of the carpal and tarsal bones. In a study of three consanguineous families and one non-consanguineous family, linkage analysis was used to establish the chromosomal location of the disease gene. Linkage analysis localised the disease gene to chromosome 3p14. A maximum lod score of 6.49 (q = 0) was obtained for the marker at locus D3S3532 on chromosome 3p. Recombination mapping narrowed the linked region to the 5.7 cM genetic interval between the markers at loci D3S3724 and D3S1300. A common region of homozygosity was found between the markers at loci D3S3724 and D3S1300, defining a physical interval of approximately 4 million base pairs likely to contain the disease gene. Identification of the gene responsible for this disorder will provide insight into the genes that play a role in the formation of the vertebral column and joints.

Erythropoietin upregulates angiotensin receptors in cultured rat vascular smooth muscle cells.

OBJECTIVE: Plasma renin is not elevated in recombinant human erythropoietin (rhEPO)-induced hypertension but angiotensin converting enzyme inhibitors reduce blood pressure in both human and animal studies. Since rhEPO elevates renin and angiotensinogen messenger RNAs in angiotensin II target tissues such as the aorta, we explored the actions of rhEPO on renin-angiotensin system-related gene transcription of cultured rat vascular smooth muscle cells. DESIGN AND METHODS: To separate direct actions of rhEPO from those mediated secondarily by potential activation of the renin-angiotensin system, vascular smooth muscle cells were cultured with rhEPO and enalapril to inhibit the angiotensin converting enzyme and losartan to inhibit angiotensin II type 1 receptors. RESULTS: Vascular smooth muscle cells cultured with rhEPO (6-8 units/ml) demonstrated elevations (40-120%) in messenger RNAs of the renin-angiotensin system (renin, angiotensinogen, angiotensin receptor types 1 and 2) and increased levels of several messenger RNAs known to respond to angiotensin II (transforming growth factor-beta, insulin-like growth factor-II, epidermal growth factor, c-fos and platelet-derived growth factor). In contrast, cells cultured in the presence of rhEPO and enalapril or losartan showed elevations of messenger RNA for only the two types of angiotensin II receptor. This increase was higher than that obtained when cells were cultured with rhEPO or either antagonist alone. The increase in specific binding of angiotensin II to cells cultured in the presence of rhEPO and enalapril or rhEPO and losartan paralleled the changes in receptor messenger RNA. CONCLUSIONS: rhEPO exerts its primary action on vascular smooth muscle cells via an increase in angiotensin receptor messenger RNA, resulting in a parallel increase in angiotensin II receptor expression. We suggest that increased receptor expression secondarily mediates the expression of other renin-angiotensin system messenger RNAs, which leads to angiotensin II-responsive gene transcription. The elevation in angiotensin II receptors, as observed in response to rhEPO, may provide a mechanism by which other forms of renin-dependent hypertension are initiated.

Experimental ocular toxoplasmosis induced in naive and preinfected mice by intracameral inoculation.

We have developed a murine model to investigate the pathogenesis of acquired ocular toxoplasmosis. Tachyzoites of PLK strain of Toxoplasma gondii were intracamerally inoculated under anesthesia into the right eyes of naive or perorally preinfected C57BL/6 and MRL-MpJ mice. Clinical and histopathological observations of responses to intraocular infection were analyzed. Ocular inflammation from Toxoplasma gondii is dose-dependent in both strains of mice. After inoculation of fifty parasites, no evidence of inflammation was observed in the eyes of naive mice. The eyes of naive mice that received 500 or 5,000 parasites developed inflammatory changes by day 6 post challenge. By day 8, the changes progressed to moderate to severe intraocular inflammation. Histologic analysis of the ocular lesions demonstrated mononuclear cell infiltration and necrosis predominantly in the anterior segment of the eyes of the naive mice. Inoculation of 50,000 tachyzoites induced a destructive ocular inflammatory response and was uniformly lethal to the mice by approximately one week after challenge. In contrast, eyes from mice previously orally infected with Toxoplasma gondii and that received a 50 or 500 parasite intracameral challenge revealed no inflammation, but the eyes receiving 5,000 parasites demonstrated necrotic focal retinochoroiditis with vitreitis by day 8 after challenge. The murine model reproduces some features of ocular toxoplasmosis in humans and may be suitable for large-scale controlled studies of the pathogenesis and therapeutics of acquired ocular toxoplasmosis as well as for study of the mechanisms of immune privilege in the eye.

The importance of non-vitamin D-mediated calcium absorption.

In rapidly growing neonatal rats, the intestine is insensitive to vitamin D, and Ca absorption is solely mediated through a non-energy-dependent process. Changes in Ca absorption associated with pregnancy and lactation are qualitatively similar in vitamin D-replete and vitamin D-deplete rats. Moreover, in vivo studies in man and the rat have demonstrated that the bulk of Ca absorption is accomplished in the ileum, a segment with limited capacity for active Ca absorption and is relatively insensitive to the action of 1,25-dihydroxyvitamin D. In patients with intestinal bypass operations the degree of Ca malabsorption and bone mineral loss is proportional to the length of ileum, not duodenum or proximal intestine, removed. Bile salts and lactose are examples of agents which can augment vitamin D-independent ileal Ca absorption through the intercellular pathway.

Variables for predicting serious toxicity (vinblastine dose, performance status, and prior therapeutic experience): chemotherapy for metastatic testicular cancer with cis-dichlorodiammineplatinum(II), vinblastine, and bleomycin.

Combination chemotherapy utilizing high-dose vinblastine, bleomycin, and cisdichlorodiammineplatinum(II) (CDDP) is effective treatment for metastatic testicular cancer. Unfortunately, it is frequently associated with serious toxicity. In a series of 14 patients receiving 65 treatment cycles, several variables were examined as putative risk factors for prediction of serious toxicity. These included drug dose normalized to body weight or surface area, interval since previous cycle, prior therapeutic experience with either radiation therapy or other cytotoxic chemotherapy, and Karnofsky performance status. The strongest determinant of serious toxicity was the vinblastine dose calculated according to body weight. The next most influential prognostic variables were the performance status and a history of previous treatment with either radiation therapy or chemotherapy. Serious toxicity may be anticipated at a frequency of 40% when vinblastine is administered at a total dose of 0.36 mg/kg with bleomycin and CDDP. In our group of patients, the nephrotoxicity of CDDP appeared to be cumulative despite intensive diuresis at the time of administration. Pulmonary toxicity was not observed. Modest reductions in vinblastine dose, especially in patients with poor performance status or a history of previous radiation or other chemotherapy, will substantially lower the frequency of serious toxicity.

Vitamin D-independent regulation of calcium and phosphate absorption.

Convincing evidence for the stimulatory action of 1,25-dihydroxyvitamin D (1,25(OH2)D) on transcellular absorption of calcium (Ca) and inorganic phosphate (P) has led to the consensus that this hormone is the major regulator of Ca and P absorption. Careful review of the literature, however, suggests important regulation of Ca and P absorption by factors and agents other than those mediated by vitamin D. Thus, in rapidly growing neonatal rats, the intestine is insensitive to vitamin D and Ca absorption is entirely mediated through passive mechanisms. Patterns of change in Ca absorption associated with pregnancy and lactation are identical in vitamin D-replete and vitamin D-deplete rats. The presence of active Ca and P absorption in young, growing rats rigidly deprived of vitamin D and of active Ca and P secretion in mature rats optimally replete with vitamin D, also suggests the participation of non-vitamin D factors in the regulation of intestinal Ca and P absorption. The possibility that Ca and P in the peri-enterocyte environment may regulate their own absorption is discussed. Kinetic analysis of 1,25(OH2)D-induced transport mechanisms indicates that saturation would occur at low substrate concentrations, thus raising the question whether these mechanisms would have major regulatory roles under normal dietary conditions. There is also suggestive evidence indicating that even under conditions of low dietary Ca or P intake, the adaptive changes in intestinal absorption may not be mediated by vitamin D alone. Bile salts, lactose and prolactin are discussed as examples of agents which can stimulate Ca and/or P absorption through vitamin D-independent mechanisms.

Paracellular phosphate absorption in rat colon: a mechanism for enema-induced hyperphosphatemia.

The mechanism of colonic phosphate absorption is not well defined. We measured unidirectional phosphate fluxes across rat distal colon epithelium in the absence of transepithelial electrochemical gradients. Steady-state mucosal-to-serosal flux (Jms) was not different from the serosal-to-mucosal flux (Jsm), generating no net flux (Jnet = Jms - Jsm, was not different from "0'). Simultaneous fluxes of mannitol, a paracellular probe, exhibited an identical flux pattern, suggesting that phosphate flux across the colonic epithelium may be mediated through the paracellular pathway. Tight junction permeability was increased with mucosal addition of taurodeoxycholate (TDC, 2 mM) which caused a prompt increase in transepithelial conductance from 7.03 +/- 0.35 to 13.88 +/- 0.35 mS/cm2 (p < 0.001). This was associated with an increase in Jsm, but no change in Jms, for mannitol, resulting in a net flux in the secretary direction. Identical TDC-induced changes were observed in phosphate fluxes, again suggesting phosphate permeation through the intercellular, mannitol pathway. A significant correlation was observed between the permeability of phosphate and the permeability of mannitol, measured both in the mucosal-to-serosal and the serosal-to-mucosal directions and under both control and experimental (mucosal TDC) conditions. Thus, colonic phosphate transport is mediated through the paracellular pathway and enema with high phosphate concentrations (1,760 times blood concentration), can trigger rapid and massive phosphate absorption through this diffusive pathway.

Bile salts and ileal calcium transport in rats: a neglected factor in intestinal calcium absorption.

Ileum displays little active transcellular calcium (Ca2+) absorption but is credited with the bulk of Ca2+ absorbed in vivo. We examined the effect of taurodeoxycholic acid (TDC, 2 mM), a bile salt, on mannitol (MN, a marker of intercellular solute traffic) and Ca2+ fluxes in rat ileum. In the absence of electrochemical gradients between the mucosal (M) and serosal (S) bathing media in an Ussing chamber, net flux (Jnet) was observed in the S-to-M direction for both MN and Ca2+, i.e., the unidirectional secretory S-to-M flux (Js-->m) exceeded the absorptive M-to-S flux (Jm-->s). Mucosal TDC caused simultaneous increase in transepithelial conductance and Js-->m for both MN and Ca2+. This was followed by even greater increases in MN and Ca2+ Jm-->s, so that ultimately Jm-->s equaled Js-->m in each case. In control tissue, Js-->m for Ca2+ appeared to permeate exclusively through the intercellular MN pathway while part of Jm-->s for Ca2+ appeared to traverse through a non-MN route. After the TDC-induced increase in intercellular solute permeability, both Ca2+ fluxes appeared to traverse through the aqueous MN conduit. During the postprandial state, the presence of bile salts and the relative abundance of Ca2+ in ileal lumen can cause bulk Ca2+ absorption through the intercellular pathway.

Feasibility of a partial meal replacement plan for weight loss in low-income patients.

BACKGROUND: Low-income patients are disproportionately affected by obesity. Routine care is available to this population at the Venice Family Clinic (VFC) in Los Angeles. The current study examined the effectiveness of nutrition clinic utilizing meal replacements (Slim-Fast, Slim-Fast Foods Co., FL, USA) in low-income patients over a 6-month period compared with the routine care by their primary care physician (PMD) prior to enrolling in the nutrition clinic at similar time intervals. METHODS: In total, 63 patients (51 F; 49+/-0.8 yo) who had been followed at the VFC by their PMD for at least 6 months were enrolled in this study. Patients had a body mass index (BMI) of 40+/-1.1 kg/m2, were 72% Hispanic, 25% Caucasian, and 3% African American. They had the following co-morbidities: hypertension (HTN) 45%, diabetes mellitus II (DM II) 50%, gastroesophageal reflux disease (GERD) 34%, osteoarthritis 51%, and hypercholesterolemia 48%. All patients were provided with meal replacements to be taken twice a day and were instructed to consume one complete low calorie meal per day. Weights at the first visit to the nutrition clinic, 1, 3, and 6 months after enrollment in nutrition clinic were compared to their weights at the same time intervals during routine visits to their PMD prior to enrollment in the nutrition clinic. RESULTS: There was no significant weight change during the 6 months prior to enrollment in the nutrition program despite receiving care by a PMD. At 6 months after participating in the nutrition program, there was a mean decrease of 7% body weight with a reduction in BMI from 40-37 kg/m2 (P< or =0.05). CONCLUSION: Implementation of nutrition clinic utilizing meal replacements in this low-income patient population was effective in achieving a significant reduction in weight over 6 months of treatment..

Role of parathyroid hormone in rat remnant kidney ammonium metabolism.

The role of parathyroid hormone (PTH) in ammonium metabolism in the rat remnant kidney was studied by examining the effects of parathyroidectomy (PTx) in rats with intact kidneys and with 5/6 nephrectomy (Nx). PTx in rats with intact kidneys caused a rise in urine pH and a decrease in urinary ammonium excretion without affecting in vitro ammonium production rate or the ammonium content in the cortex. Unexpectedly, the ammonium content in the medulla was markedly reduced by PTx so that the corticomedullary ammonium gradient was inverted. As compared to control rats, rats with 5/6 Nx had a lower urinary ammonium excretion rate, a higher in vitro ammonium production rate, and an increase in ammonium content in both cortex and medulla with reduced corticomedullary ammonium gradient. PTx in rats with 5/6 Nx led to a further decrease in urinary ammonium excretion, attenuated the increase in the in vitro ammonium production rate, and lowered the ammonium content in both cortex and medulla with inverted corticomedullary ammonium gradient. These effects of PTx in Nx rats were corrected by continuous PTH infusion with Alzet minipump. In summary, results from these studies indicate that PTH plays an important role in maintaining the urinary ammonium excretion. In rats with intact kidneys, PTH contributes to urinary ammonium excretion by increasing urinary acidification and medullary ammonium accumulation. In rats with reduced nephron mass, PTH enhances urinary ammonium excretion by stimulating ammonium production and retaining medullary ammonium in the remnant kidney.

Influence of recombinant human erythropoietin on blood pressure and tissue renin-angiotensin systems.

In humans, blockade of the renin-angiotensin system with angiotensin converting-enzyme inhibitors (ANG CEI) prevents the rise in blood pressure associated with the administration of recombinant human erythropoietin (rhEPO). This study was conducted to determine whether rhEPO elevates blood pressure in normal Wistar rats and whether the renin-ANG system is affected. Groups of 10 rats each were given rhEPO, ANG CEI (enalapril), rhEPO + ANG CEI, or vehicle. Renin and/or renin substrate mRNA was measured in aortas, kidney, and heart; renin activity (PRA), inactive renin, and renin substrate were measured in plasma. rhEPO raised blood pressure in the normal rat without changing the plasma renin system. ANG CEI prevented this blood pressure rise. Renin-specific mRNA was increased by rhEPO in renal tissue, and renin substrate mRNA was significantly elevated in the kidney and aorta. mRNA for renin and renin substrate were not altered in the heart. In both aorta and kidney, a significant correlation was observed between renin substrate mRNA and blood pressure. The data indicate that rhEPO modulates specific tissue renin-ANG systems, which may contribute to blood pressure elevation.

Rapid hypertensinogenic effect of lead: studies in the spontaneously hypertensive rat.

Chronic lead exposure may cause hypertension in normotensive rats. This hypertensinogenic effect has been attributed to perturbations in the renin-angiotensin axis, the contractile response of the vascular smooth muscle, or the intracellular Ca2+ homeostasis as a consequence of the inhibition of Na(+)-K(+)-ATPase activity. In this study we examined the short-term effect of lead exposure on blood pressure, plasma renin activity, vascular contractility, and renal Na(+)-K(+)-ATPase activity and abundance in the spontaneously hypertensive rat. Our data indicate that modest lead exposure caused blood pressure elevation within two weeks in this rat strain that is genetically susceptible to the development of hypertension. This rapid blood pressure-elevating effect did not appear to depend on the mechanisms described in hypertension associated with more chronic lead exposure listed above. This acute model provides an additional approach to the study of lead-induced hypertension.

Fas-FasL interaction involved in pathogenesis of ocular toxoplasmosis in mice.

Ocular toxoplasmosis is a potentially blinding intraocular inflammation. The intent of this study was to investigate the role of Fas-FasL interaction in a murine model of acquired ocular toxoplasmosis induced by intracameral inoculation of Toxoplasma gondii. Intraocular inflammation, Fas and FasL expression on lymphocytes and on ocular tissues, the occurrence of apoptosis, and the frequency of CD8(+) and CD4(+) T cells in the infected eyes were analyzed in C57BL/6 (B6) mice. Susceptibility to parasite-induced intraocular inflammation was observed in Fas-deficient (B6-lpr) and FasL-deficient (B6-gld) mice. Inoculation of 5,000 T. gondii tachyzoites induced significant intraocular inflammation associated with increase of Fas and FasL expression in the inoculated eyes of wild-type B6 mice. Flow cytometry demonstrated a significant increase of Fas and FasL expression on the splenocytes from naive mice incubated in vitro with the parasite and on the splenocytes harvested from the infected mice at day 8 after parasite inoculation. Apoptosis of inflammatory cells and cells in ocular tissues was seen, and a greater frequency of CD8(+) than CD4(+) T cells was observed in the infected eyes. The intensity of intraocular inflammation was greater in B6-lpr and B6-gld mice than in wild-type B6 mice (P < 0.05). The results suggest that Fas-FasL interaction associated with apoptosis is involved in the pathogenesis of acquired ocular toxoplasmosis in mice.