Centrality dependence of charged particle multiplicity in Au-Au collisions at square root of (s)NN = 130 GeV

We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality.

Rescue of contractile parameters and myocyte hypertrophy in calsequestrin overexpressing myocardium by phospholamban ablation

Cardiac-specific overexpression of murine cardiac calsequestrin results in depressed cardiac contractile parameters, low Ca(2+)-induced Ca(2+) release from sarcoplasmic reticulum (SR) and cardiac hypertrophy in transgenic mice. To test the hypothesis that inhibition of phospholamban activity may rescue some of these phenotypic alterations, the calsequestrin overexpressing mice were cross-bred with phospholamban-knockout mice. Phospholamban ablation in calsequestrin overexpressing mice led to reversal of the depressed cardiac contractile parameters in Langendorff-perfused hearts or in vivo. This was associated with increases of SR Ca(2+) storage, assessed by caffeine-induced Na(+)-Ca(2+) exchanger currents. The inactivation time of the L-type Ca(2+) current (I(Ca)), which has an inverse correlation with Ca(2+)-induced SR Ca(2+) release, and the relation between the peak current density and half-inactivation time were also normalized, indicating a restoration in the ability of I(Ca) to trigger SR Ca(2+) release. The prolonged action potentials in calsequestrin overexpressing cardiomyocytes also reversed to normal upon phospholamban ablation. Furthermore, ablation of phospholamban restored the expression levels of atrial natriuretic factor and alpha-skeletal actin mRNA as well as ventricular myocyte size. These results indicate that attenuation of phospholamban function may prevent or overcome functional and remodeling defects in hypertrophied hearts.

Stented elephant trunk method for multiple thoracic aneurysms

Stent-grafting and open graft replacement was introduced to reduce the complications of suture anastomosis in the descending aorta. We applied this technique in the treatment of a patient with multiple thoracic aneurysms. The elephant trunk procedure was used for thromboexclusion. A single branched graft was placed easily without twisting. In patients with aneurysms at both the proximal and distal thoracic aorta, combined stent-grafting and open graft replacement is an excellent approach.

[A case report of Ebstein's anomaly treated with Hetzer's procedure]

A 27-year-old male who had been diagnosed with Ebstein's anomaly was admitted with uncontrollable congestive heart failure. The echocardiogram revealed severe tricuspid valve incompetence and the electrocardiogram showed atrial fibrillation. He underwent Hetzer's repair procedure for tricuspid valve incompetence and Minzioni's right atrial isolation technique to restore sinus rhythm. His congestive heart failure quickly disappeared and sinus rhythm was restored after operation. He was discharged 3 weeks postoperatively and remains well 22 months after his operation. Hetzer's technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. We conclude that Hetzer's procedure is an effective operation for Ebstein's anomaly.

Three-pion interferometry results from central Pb+Pb collisions at 158A GeV/c

Three-particle correlations have been measured for identified pi(-) from central 158A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.

Atherosclerotic aneurysm of the intrathoracic segment of the subclavian artery: a case report

True aneurysms of the intrathoracic segment of the subclavian artery are extremely rare. Atherosclerosis is the most common etiology. The surgical approach and timing of repair remain controversial. We successfully treated a patient with a large proximal subclavian artery aneurysm which was secondary to atherosclerosis. The patient was asymptomatic for 30 years as the aneurysm enlarged. Three-dimensional computed tomography provided the most useful information regarding anatomy of the cervical vasculature. The patient underwent closure of the inlet port of the aneurysm and repair using a 6-mm Dacron bypass graft (Gelsoft , VASCTEK, Scotland) via a minimally invasive surgical approach.

Comparative evaluation of a 5-day Hershberger assay utilizing mature male rats and a pubertal male assay for detection of flutamide's antiandrogenic activity

A 5-day Hershberger assay utilizing mature male rats and a pubertal male assay were evaluated for the ability to detect antiandrogenic compounds such as flutamide, an androgen receptor antagonist. Six days after the operation, implantation with two silicon capsules containing testosterone (T) (30 mg/capsule) in castrated rats provided the ventral prostate and seminal vesicle weights as well as serum T and luteinizing hormone (LH) levels equivalent to those of the controls (non-castrated, non-implanted rats). Castrated rats implanted with two T-capsules (6 rats/dose) were treated by gavage for 5 days with vehicle (0.5% carboxymethylcellulose) or flutamide (0.15, 0.6, 2.5, or 10 mg/kg/day). Flutamide produced significant decreases in weights of the seminal vesicles and the levator ani plus bulbocavernosus muscles (> or =0.6 mg/kg/day) and ventral prostate (> or =2.5 mg/kg/day), and an increase in serum LH levels (> or =2.5 mg/kg/day), but no changes in serum T levels. When age-matched intact male rats were treated with 10-mg/kg/day flutamide, a significant increase in serum T levels was observed concomitant with a tendency of increased LH. The organ weights were also decreased; however, the changes were less than those in the castrated, T-implanted rats. Immature intact male rats (10 rats/dose) were treated for 20 days with flutamide (0, 0.15, 0.6, 2.5, or 10 mg/kg/day). Flutamide produced significant decreases in weights of the seminal vesicles, ventral prostate, and levator ani plus bulbocavernosus muscles at 2.5 and 10 mg/kg/day. Serum LH levels, but not T levels, were increased at 10 mg/kg/day. Statistical significance of some of these changes was not observed in the 6 animals/dose examined. Our findings support that the Hershberger assay, in the current conditions, is the most sensitive among the assays examined and a useful short-term screening method for the detection of antiandrogenic compounds.

Surgical treatment of abdominal aortic aneurysms located close to the visceral arteries: report of three cases

The standard surgical treatment for abdominal aortic aneurysms (AAA) is in situ replacement of the infrarenal aorta, which is associated with a low mortality rate. On the other hand, thoracoabdominal aortic aneurysms (TAA) remain a formidable challenge and the complications that can occur may be severe including neurologic dysfunction and renal failure. We report herein three cases of patients with AAA located very close to the visceral arteries, for which in situ replacement of the infrarenal aorta was not feasible due to severe inflammation and adhesion. Therefore, aortic stump closure and in situ bypass grafting was performed to avoid reconstruction of the visceral arteries. No major complications or operation-related deaths occurred. Thus, while in situ replacement is usually recommended over bypass grafting for patients whose aneurysms are located very close to the visceral arteries, aortic stump closure and in situ bypass grafting should be considered as a more effective surgical option.

Cardiac-specific overexpression of Galphaq alters excitation-contraction coupling in isolated cardiac myocytes

Transgenic mice with cardiac-specific overexpression of G alpha q exhibit a biochemical and physiological phenotype of load-independent cardiac hypertrophy with contractile dysfunction. To elucidate the cellular basis for altered contractility, we measured cellular contraction, Ca(2+)transients, and l -type Ca(2+)channel currents (I(Ca)) in left ventricular (LV) myocytes isolated from non transgenic (NT) controls or G alpha q hearts. Although baseline contractile function (% shortening) and the amplitude of Ca(2+)transients in G alpha q myocytes were similar to NT myocytes, the rates of cellular shortening and relengthening and the duration of Ca(2+)transients were prolonged in G alpha q myocytes. Myocytes from G alpha q hearts had larger cell capacitance but no change in I(Ca)density, voltage-dependence of activation and inactivation. The responses of I(Ca)to dihydropyridine drugs and a membrane permeable cAMP analog, 8-(4-chlorophenylthio) cAMP, were not altered; however, the time course of I(Ca)inactivation was significantly slower in G alpha q myocytes compared to NT myocytes. The kinetic difference in inactivation was abolished when Ba(2+)was used as the charge carrier or when the sarcoplasmic reticulum (SR) Ca(2+)was depleted by ryanodine, suggesting that Ca(2+)-dependent inactivation is reduced in G alpha q myocytes due to altered SR Ca(2+)release. Consistent with this hypothesis, the function of SR as assessed by the maximal Ca(2+)uptake rates and the apparent affinity of SR Ca(2+)-ATPase for Ca(2+)was reduced in ventricles of G alpha q heart. These results suggest that the reduced SR function contributes to the depressed contractility associated with this form of cardiac hypertrophy.

Familial hyperparathyroidism: report of a case

We report herein a case of familial primary hyperparathyroidism diagnosed in a 23-year-old woman who presented with hypercalcemia and urolithiasis. The parathyroid gland was removed, and pathological examination revealed chief cell adenoma. The proband's younger sister had undergone surgery for parathyroid adenoma at the age of 19, and her aunt had a history of urolithiasis with a high level of serum parathyroid hormone. We have not yet found evidence of any other endocrine disorders suggesting multiple endocrine neoplasia (MEN) type 1 in this pedigree.

Experimental study of seita-fitting

The purpose of this study was to verify the difference between carrying a load on the sacrum (LOS) and on the lumbar vertebrae (LOL) in oxygen uptake, muscle activities, heart rate, cadence, and subjective response. Nine males (26.7 +/- 3.1 years old), each carrying a 7.5 kg carrier frame and a 40 kg load, walked on a treadmill at a speed of 50 m/min. EMGs were recorded from the trapezius, rectus abdominis, erector spinae, vastus lateralis, rectus femoris, vastus medialis, biceps femoris long head, tibial anterior, soleus, medial head of gastrocnemius, and the lateral head of gastrocnemius. For each subject the integrated EMG (IEMG) was normalized by dividing the IEMG in the LOL and LOS by the IEMG in a no-load condition (NL) for each investigated muscle. The following was significantly higher in LOL than in LOS: oxygen uptake; IEMG of the tibial anterior, soleus, and medial head of gastrocnemius; cadence; and rated perceived exertion. However, IEMG of the erector spinae was significantly lower in LOL than in LOS. These results suggest that seita-fitting in LOS causes a decrease of leg muscle activities, which causes oxygen uptake to decrease beyond the increase of the erector spinae activity.

Cardiac-specific overexpression of mouse cardiac calsequestrin is associated with depressed cardiovascular function and hypertrophy in transgenic mice

Calsequestrin is a high capacity Ca2+-binding protein in the sarcoplasmic reticulum (SR) lumen. To elucidate the functional role of calsequestrin in vivo, transgenic mice were generated that overexpressed mouse cardiac calsequestrin in the heart. Overexpression (20-fold) of calsequestrin was associated with cardiac hypertrophy and induction of a fetal gene expression program. Isolated transgenic cardiomyocytes exhibited diminished shortening fraction (46%), shortening rate (60%), and relengthening rate (60%). The Ca2+ transient amplitude was also depressed (45%), although the SR Ca2+ storage capacity was augmented, as suggested by caffeine application studies. These alterations were associated with a decrease in L-type Ca2+ current density and prolongation of this channel's inactivation kinetics without changes in Na+-Ca2+ exchanger current density. Furthermore, there were increases in protein levels of SR Ca2+-ATPase, phospholamban, and calreticulin and decreases in FKBP12, without alterations in ryanodine receptor, junctin, and triadin levels in transgenic hearts. Left ventricular function analysis in Langendorff perfused hearts and closed-chest anesthetized mice also indicated depressed rates of contraction and relaxation of transgenic hearts. These findings suggest that calsequestrin overexpression is associated with increases in SR Ca2+ capacity, but decreases in Ca2+-induced SR Ca2+ release, leading to depressed contractility in the mammalian heart.

Ca2+ entry through cardiac L-type Ca2+ channels modulates beta-adrenergic stimulation in mouse ventricular myocytes

beta-adrenergic receptor (beta-AR) stimulation increases cardiac L-type Ca2+ channel (CaCh) currents via cAMP-dependent phosphorylation. We report here that the affinity and maximum response of CaCh to isoproterenol (Iso), in mouse ventricular myocytes were significantly higher when Ba2+ was used as the charge carrier (IBa) instead of Ca2+ (ICa). The EC50 and maximum increase of peak currents were 43.7 +/- 7.9 nM and 1.8 +/- 0.1-fold for ICa and 23.3 +/- 4.7 nM and 2.4 +/- 0.1-fold for IBa. When cells were dialyzed with the faster Ca2+ chelator, BAPTA, both sensitivity and maximum response of ICa to Iso were significantly augmented compared to cells with EGTA (EC50 of 23.1 +/- 5.2 nM and maximal increase of 2.2 +/- 0.1-fold). Response of ICa to forskolin was also significantly increased when cells were dialyzed with BAPTA or when currents were measured in Ba2+. In contrast, depletion of the sarcoplasmic reticulum (SR) Ca2+ stores by ryanodine did not alter sensitivity of ICa to Iso or forskolin. These results suggest that the Ca2+ entering through CaCh regulates cAMP-dependent phosphorylation, and such negative feedback may play a significant role in cellular Ca2+ homeostasis and contraction in cardiac cells during beta-AR stimulation.

Overexpression of phospholamban alters inactivation kinetics of L-type Ca2+ channel currents in mouse atrial myocytes

In mammalian ventricular myocytes, inactivation of L-type Ca2+ channels (CaCh) is controlled by voltage- and Ca2+-dependent mechanisms. The Ca2+-dependent component is regulated by the Ca2+ released from the sarcoplasmic reticulum (SR). However, little is known about the inactivation properties of CaCh in atrial myocytes, which lack spatial coupling between CaCh and SR Ca2+ release channels. The cardiac SR Ca2+ load is determined by the activity of SR Ca2+-ATPase, which is inversely regulated by the levels of phospholamban (PLB). To investigate the role of SR Ca2+ in atrial myocytes, Ca2+ currents (I Ca) were recorded in mouse atrial myocytes recorded from wild-type (WT) mice and the characteristics were compared to those obtained from atrial myocytes from the transgenic mice overexpressing PLB (PLB-OEX). ICa from WT exhibited fast and slow components of inactivation and the rate of inactivation was slowed when SR Ca2+ was depleted by caffeine, suggesting that the inactivation of atrial ICa is modulated by SR Ca2+ load. The current density and voltage-dependence of ICa were similar between the two groups. However, the fast component of inactivation was significantly reduced in PLB-OEX. When Ca2+ was replaced by Ba2+ or in the presence of caffeine, inactivation was slowed and the decay of the current was not significantly different between WT and PLB-OEX. These results suggest that the inactivation of ICa in mouse atrial myocytes involves Ca2+-dependent and voltage-dependent components. The decrease in the faster component of inactivation in PLB-OEX is consistent with the idea that CaCh and SR Ca2+ release channels are functionally coupled and Ca2+ released from the SR contributes the Ca2+-dependent inactivation component.

Azathioprine-induced megaloblastic anemia with pancytopenia 22 years after living-related renal transplantation

Macrocytosis and megaloblastic changes in the bone marrow are frequently seen in renal transplant recipients treated with azathioprine (Az). However, severe anemia is a rare side effect of Az. We recently observed a case of severe megaloblastic anemia with pancytopenia in a renal transplant recipient who had been receiving Az therapy for 22 years. The patient was a 46-year-old woman who had been administered Az and prednisolone at a dose of approximately 1.7 mg/kg and 0.17 mg/kg daily, respectively. A bone marrow aspiration revealed megaloblastic anemia with the depletion of myeloid cells and megakaryocytes. She did not have vitamin B12 or folate deficiency. Therefore, FK506 (tacrolimus), a macrolide produced by Streptomyces tsukubaensis, which acts directly on T cells and is known to have less myelosuppression than Az, was substituted for Az. Although the leukopenia improved, the anemia and thrombocytopenia did not improve in the short term. She developed dyspnea and severe subcutaneous bleeding of the right lower extremity due to knee contusions. Hemodialysis was started to treat her uremic state. Although it was impossible to evaluate the long-term effects of FK506 therapy for the pancytopenia in our case, the conversion from Az to a less myelosuppressive drug, such as FK506, should be considered in renal transplant recipients with severe myelosuppression caused by long-term Az treatment.

Modulation of cardiac Ca2+ channels by isoproterenol studied in transgenic mice with altered SR Ca2+ content

Phospholamban (PLB) ablation is associated with enhanced sarcoplasmic reticulum (SR) Ca2+ uptake and attenuation of the cardiac contractile responses to beta-adrenergic agonists. In the present study, we compared the effects of isoproterenol (Iso) on the Ca2+ currents (ICa) of ventricular myocytes isolated from wild-type (WT) and PLB knockout (PLB-KO) mice. Current density and voltage dependence of ICa were similar between WT and PLB-KO cells. However, ICa recorded from PLB-KO myocytes had significantly faster decay kinetics. Iso increased ICa amplitude in both groups in a dose-dependent manner (50% effective concentration, 57.1 nM). Iso did not alter the rate of ICa inactivation in WT cells but significantly prolonged the rate of inactivation in PLB-KO cells. When Ba2+ was used as the charge carrier, Iso slowed the decay of the current in both WT and PLB-KO cells. Depletion of SR Ca2+ by ryanodine also slowed the rate of inactivation of ICa, and subsequent application of Iso further reduced the inactivation rate of both groups. These results suggest that enhanced Ca2+ release from the SR offsets the slowing effects of beta-adrenergic receptor stimulation on the rate of inactivation of ICa.

cAMP-dependent regulation of cardiac L-type Ca2+ channels requires membrane targeting of PKA and phosphorylation of channel subunits

The cardiac L-type Ca2+ channel is a textbook example of an ion channel regulated by protein phosphorylation; however, the molecular events that underlie its regulation remain unknown. Here, we report that in transiently transfected HEK293 cells expressing L-type channels, elevations in cAMP resulted in phosphorylation of the alpha1C and beta2a channel subunits and increases in channel activity. Channel phosphorylation and regulation were facilitated by submembrane targeting of protein kinase A (PKA), through association with an A-kinase anchoring protein called AKAP79. In transfected cells expressing a mutant AKAP79 that is unable to bind PKA, phosphorylation of the alpha1C subunit and regulation of channel activity were not observed. Furthermore, we have demonstrated that the association of an AKAP with PKA was required for beta-adrenergic receptor-mediated regulation of L-type channels in native cardiac myocytes, illustrating that the events observed in the heterologous expression system reflect those occurring in the native system. Mutation of Ser1928 to alanine in the C-terminus of the alpha1C subunit resulted in a complete loss of cAMP-mediated phosphorylation and a loss of channel regulation. Thus, the PKA-mediated regulation of L-type Ca2+ channels is critically dependent on a functional AKAP and phosphorylation of the alpha1C subunit at Ser1928.

Benign cervical teratoma in an adult: report of a case

Cervical teratomas are rarely encountered in adults. We report herein the case of a 21-year-old woman who was admitted to our hospital for surgical treatment of a neck tumor, 7.5 x 4.5 x 2.7 cm in size, located in the left lower pole of the thyroid. Ultrasonography (US) and computed tomography (CT) revealed a multicystic tumor. The levels of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and squamous cell carcinoma-related antigen (SCC) in the cystic fluid were extremely elevated in contrast to the normal levels found in the serum. The tumor was completely excised and histological examination revealed it to be composed of elements derived from the three germ layers, confirming a diagnosis of benign cystic teratoma.

Iliac artery dissection originating in a true aneurysm. A case report

The spontaneous dissection of a peripheral artery not involving the aorta is rare and usually does not arise from a true aneurysm. This is the first report of a spontaneous external iliac artery dissection originating in a true aneurysm.

[Dynamic Gd-DTPA-enhanced MR imaging in evaluation of the function of transplanted kidneys]

The purpose of the study was to evaluate the potential of dynamic Gd-DTPA-enhanced MR imaging in assessing of the function of transplanted kidneys. Dynamic MR imaging was performed using the GRASS pulse sequence in 21 subjects (56 examinations), and in each examination 30 images were obtained after a bolus injection of Gd-DTPA. Imaging findings including signal increase and/or signal drop in cortex, signal drop in medulla, and signal drop in calyces were utilized for the evaluation of renal function. Renal function was also evaluated using the following parameters: Ta, time between the initial observation of signal increase in cortex and signal drop in medulla. Tb, time between the initial observation of signal drop in medulla and in calyces; Tc, Ta + Tb, and Max. C/M, maximum ratio of signal intensity between cortex and medulla among 30 images. In the group of patients with normal graft function (Ccr > or = 60ml/min), all imaging findings were observed. In the group of patients with mild graft dysfunction (30ml/min < or = Ccr < 60ml/min), all imaging findings but signal drop in cortex were observed. The time parameters of Ta, Tb, and Tc were significantly larger, and Max. C/M was significantly smaller than those observed in the group with normal graft function. In the group of patients with severe graft dysfunction (Ccr < 30ml/min), almost none of the findings were observed. The investigation in patients in the postoperative state revealed a close correlation of the imaging findings and the values of parameters with changes in graft function over time. The results indicated the usefulness of the method in semiquantitative evaluation of graft function, including that of patients in postoperative state. This study suggests that dynamic Gd-DTPA-enhanced MR imaging could be a valuable method for the management of transplanted kidneys.

[A clinical study of recurrent breast cancer]

In a recent 14-year period from December 1978 to December 1993, 180 patients with breast cancer were treated at the hospital, and out of these 180 patients, 38 patients (21.1%) who had a recurrent breast cancer were clinically evaluated. The first recurrence occurred in the local skin in 13 patients, regional lymph node in 1, bone in 13, lung in 4, liver in 4 and in other areas in 3. Histologically, the incidence of scirrhous carcinoma recurrence was higher than that of papillotubular carcinomas. There was no recurrence in mucinous carcinomas. The frequency of recurrence became higher in accordance with TNM classification, namely, 6.7% in Stage I, 23.7% in Stage II, 37.5% in Stage IIIa, and 47.1% in Stage IIIb cancers. An increasing tendency in the recurrence rate was also noted with an increase of tumor diameter or lymph node metastasis. Otherwise, there was no difference in cumulative survival after recurrence between TNM classification. There were no correlations between the estrogen receptor and incidence of recurrence or 5-year survival rate. The disease free interval (DFI) was less than 2 years in about 60% of the recurrent cases. DFI of bone metastasis was longer than for the other sites of recurrence. The survival rate increased according to prolongation of DFI. After through evaluation of these results, one should pay close attention to follow-up after mastectomy.

[A case of aortic dissection associated with congenital bicuspid aortic valve]

It is known that bicuspid aortic valve with dilatation of the ascending aorta is one of risk factors of the aortic dissection. A case of acute aortic dissection (DeBakey type-II) associated with bicuspid aortic valve who underwent successfully operation 8 hours after onset is reported. This patient went into cardiogenic shock because of cardiac tamponade and aortic valve regurgitation immediately after onset. Aortic valve and the ascending aorta were replaced using composite graft (#23 SJM prosthetic aortic valve and 26 mm woven Dacron vascular graft) combined with coronary artery reconstruction by Cabrol's technique. Aortic valve showed bicuspid and histological examination revealed cystic medionecrosis and loss of elastic fiber. Postoperative course was uneventful and this patients is doing well 3 years after the operation.

A research to develop a predicting system of mammalian subacute toxicity. II. Single dose detailed toxicity studies

"Single dose detailed toxicity study" in rats was conducted with 6 chemical substances to establish a predicting system of subacute toxicity of non-congeneric industrial chemicals. In the detailed examinations, new and previously reported biological parameters were developed and utilized for the establishment and confirmation of the correlations for both qualitative and quantitative prediction of target organs and effects in repeated dose toxicity studies of non-congeners; the new parameters were concerned with liver, kidneys and blood and the established relating equations for prediction had a correlation coefficient of 0.83 (liver), 0.49 (kidneys) and 0.94 (blood), while the old parameters effectively confirmed the previous correlations. The serial changes in the study gave a biological explanation to the established relationships between acute and subacute toxicities in terms of extrapolation.

Repair of a ruptured aortic arch aneurysm complicated by postoperative paraplegia: report of a case

We report herein the rare case of a 79-year-old man who suffered permanent paraplegia after undergoing an otherwise successful total arch replacement for a ruptured aortic arch aneurysm. During cardiopulmonary bypass, perfusion to the distal aorta was maintained from the femoral artery, and postoperative aortography showed intact tributaries from the aorta including the intercostal arteries. Postoperative paraplegia is an extremely rare complication of operations on the aortic arch; however, we speculate that the paraplegia in this patient could be attributed either to a steal phenomenon involving the radicular artery, or to the anatomical particularity of the spinal cord artery described by Cole and Gutelius as the "segmental system".