Successful management of a giant spinal arteriovenous malformation with multiple communications between primitive arterial and venous structures by embolization: report of a case

A 47-year-old woman was admitted to our hospital with a giant spinal arteriovenous malformation (AVM) causing heart failure and thoracic myelopathy. Angiography revealed that the spinal AVM had multiple feeding vessels branching from the 5th through 12th intercostal arteries. The drainage vein flowed to the azygos vein and superior vena cava. The AVM destroyed the 7th thoracic vertebra. The cardiac output was 16.7l/min and the shunt ratio was 64% before treatment. Embolization with cyanoacrylate was performed because the operation was considered to be associated with a significant risk of paraplegia and organ ischemia. The cardiac output decreased to 11.6l/min and the shunt ratio was reduced to 32%. After embolization the patient demonstrated no symptoms of either heart failure or sensory deficits. During embolization, provocative tests using sodium amytal and lidocaine with magnetic stimulation were also performed. The above findings suggest that provocative tests and magnetic stimulation are useful to predict paraplegia, which could result from embolization while, in addition, embolization is considered to be a useful treatment for multiple shunt and nidus in this region.

A case of Guillain-Barré syndrome accompanied by sympathetic overactivity and hypertensive encephalopathy

Hypertension has often been observed in patients with Guillain-Barré syndrome, and various underlying mechanisms have been implicated. We report the case of a child with the Guillain-Barré syndrome whose hypertension was associated with increases in both renin activity and circulating catecholamines. This case also appeared to be complicated by hypertensive encephalopathy. Following administration of intravenous regitine, a blood pressure change was observed and cardiac performance was assessed by two-dimensional echocardiography. Results indicated that increased total peripheral resistance may have been responsible for the symptoms and the hypertension. The hypertension was effectively managed by nifedipine, captopril and prazosin without the need for beta-blockade.

Tissue factor pathway inhibitor production by human mesangial cells in culture

Fibrin formation within the glomeruli has been observed in various forms of human and experimental glomerulonephritis and it may play an important role in progressive glomerular injury. Furthermore it has been hypothesized that glomerular fibrin deposition may occur through activation of either the intrinsic or extrinsic coagulation pathway. It has been demonstrated that a procoagulant activity (PCA) which is compatible with tissue factor is present in the glomeruli and becomes increased in human proliferative glomerulonephritis and in animal models of nephritis. Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation through its ability to inhibit tissue factor activity. TFPI is present in plasma and in platelets, and it is now thought to be produced mainly by endothelial cells. We examined whether human mesangial cells (HMC) could produce TFPI and attempted to clarify regulatory factors which affect TFPI production. Cultured HMC were used and TFPI in the cell supernatants was measured by ELISA using a specific antibody. Cultured HMC showed the production of TFPI. Immunoblot analysis revealed 40 kD protein of TFPI. The concentration of TFPI was significantly increased following the incubation with thrombin and heparin, including low molecular weight heparin, in a dose- and time-dependent manner. However, fetal calf serum, phorbol myristate acetate, lipopolysaccharide, IL-1 beta and tissue factor did not stimulate TFPI synthesis. Our data show that cultured HMC have the ability to produce TFPI which inhibits fibrin formation. It is possible that thrombin-induced enhancement of TFPI synthesis may be caused by the autoregulatory system of blood coagulation and that with heparin it may represent another anticoagulatory effect of heparin.

NAD+ biosynthesis and metabolic fluxes of tryptophan in hepatocytes isolated from rats fed a clofibrate-containing diet

Hepatocytes were isolated from rats fed a diet with or without 0.25% clofibrate, and NAD+ synthesis by the hepatocytes was determined using either [carboxyl-14C]nicotinic acid or [5-3H]tryptophan. NAD+ and total pyridine nucleotides synthesized from [14C]nicotinic acid by the clofibrate-treated cells were not significantly different from those synthesized by the control cells when expressed on the basis of nanomoles per hour per milligram of DNA. On the contrary, NAD+ synthesized from [3H]tryptophan was significantly higher in the clofibrate-treated cells (158% of the control cells) on the basis of nanomoles per hour per milligram of DNA. Clofibrate was inhibitory to tryptophan metabolism as a whole, affecting the glutarate pathway more (decreased to 37% of control) than the kynureninase flux (decreased to 64% of control). As a result, the quinolinate-NAD flux, estimated as the difference in the amounts of tryptophan metabolized by the two metabolic pathways, increased in the clofibrate-treated hepatocytes. The increase in quinolinate during the incubation was 8 times more in the clofibrate-treated cells than in the control cells, which confirmed alteration in the metabolic fluxes of tryptophan in the clofibrate-treated cells. Hepatic quinolinate phosphoribosyltransferase (EC 2.4.2.19) activity increased with dietary clofibrate and returned to the control level 1 week after removing clofibrate from the diet. Nicotinate phosphoribosyltransferase (EC 2.4.2.11) and NAD+ glycohydrolase (EC 3.2.2.5) activities remained unchanged with dietary clofibrate.

[A case of Aicardi syndrome: neurophysiological investigation]

A Japanese girl developed tonic spasms in series at two months after birth. When she was admitted at 4 months, she had generalized muscle hypotonia and could not control her head. She had atotal agenesis of the corpus callosum on MRI, reticulo-lacunitis revealed by ophthalmologic examination, and hypsarrhythmia in EEG. Brain stem auditory evoked potentials and flash-visual evoked potentials exhibited abnormally asymmetrical findings. The cortical components of somatosensory evoked potentials were not elicited on admission, but some components became to be recognized on median nerve stimulation in accordance with improvement of EEG findings after various therapeutic trials. We concluded that these neurophysiological examinations were useful to investigate the abnormal lesions of the central nervous system in patients with Aicardi syndrome.

Protochlorophyllide reduction: a key step in the greening of plants

The reduction of Protochlorophyllide (Pchlide) is a major regulatory step in the biosynthesis of chlorophyll (Chl) in oxygenic phototrophs. Two different enzymes catalyze this reduction: a light-dependent enzyme (LPOR), which is unique as a consequences of its direct utilization of light for catalysis; and a light-independent Pchlide reductase (DPOR). Since the reduction of Pchlide in angiosperms is catalyzed exclusively by LPOR, they become etiolated in the absence of light. LPOR, a major protein in etioplast membranes, consists of a single polypeptide and it exists as a ternary complex with its substrates, Pchlide and NADPH. By contrast to the copious information about LPOR, limited information about DPOR has been reported. Recent molecular genetic analyses in a cyano-bacterium and a green alga have revealed that at least the three genes, namely, chlL, chlN and chlB, encode proteins essential for the activity of DPOR. These genes are widely distributed among phototrophic organisms with exception of angiosperms and Euglenophyta. This distribution seems to be well correlated with light-independent greening ability. These genes might have been lost during the evolution of gymnosperms to angiosperms. The similarities among the deduced amino acid sequences of the three gene products and the subunits of nitrogenase suggest an evolutionary relationship between DPOR and nitrogenase. The identification of genes for the reduction of Pchlide provides the groundwork for investigations of the mechanism that regulates the synthesis of Chl, which is closely coordinated with greening in plants.

["Vertigo" the fact analysis of clinical practice by ENT physicians of Chiba Prefecture by "send-out" questionnaires]

Despite the fact that vertigo has been one of the most frequent complaints encountered in daily practice in an ENT outpatient clinic, it is believed to be the most unwelcome subject for ENT physicians. The reasons are diverse; e.g., the understanding of vertigo is still a difficult task for most physicians and requires time-consuming multiple studies. However, answers to those questions, although speculated a posteriori, are yet to be substantiated. Therefore, we have analyzed the data obtained from multiple questionnaires that were addressed to ENT physicians practicing in Chiba Prefecture in November of 1993. However, those who work in publicly run hospitals were excluded from the study. The study included otorhinolaryngologists who were members of the Society of Otorhinolaryngology of Japan. We received filled questionnaire forms from 76 of 155 members (49%). The age ranged from 33 to 82 years (mean 55.8 years, 68 men and 8 women). From these questionnaires, it became apparent that physicians are not necessarily reluctant to see patients with vertigo. Instead, most ENT physicians appeared to be actively paying attention to this symptom and to be making efforts to approach its diagnosis and treatment. Although we are not certain if the data obtained here represent the majority of ENT physicians, the positive attitudes toward the patients with vertigo/dizziness would certainly encourage those of us who are interested in this particular symptom category.

[A case of chronic tuberculous pyothorax associated malignant lymphoma]

The patient was 69-year-old male. He has a history of treatment for tuberculosis by artificial pneumothorax about 47 years ago. He was admitted an another hospital under the diagnosis of tuberculous pyothorax. He was transferred to our hospital because of chest pain and fever. Laboratory findings on the admission were as follows: ESR was 120 mm/hr, CRP was 20.22 mg/dl and other data were almost within normal limits. Chest X-ray showed a massive shadow in the right lower lung field, adjacent to the chest wall. Computed tomography (CT) showed tumor shadow with low density and invasions into the adjacent chest wall. Histological examination of surgically excised tumor biopsy revealed malignant lymphoma. The patient's condition improved and the size of tumor decreased temporarily by chemotherapy. Then, he began to complain of chest pain and high fever, and tumor in the chest wall invaded into the whole chest wall. He died of disseminated intravascular coagulation despite continuing chemotherapy. Postmortem examination revealed the following findings : the tumor existed mainly in the parietal pleura or the chest wall, adjacent to the lesion of pyothorax, and immunohistochemical examination showed that tumor was malignant lymphoma, diffuse, large B-cell type. Recent studies have shown a close association between EBV infection and pyothorax-associated lymphoma. We have to keep in mind the possible development of malignant lymphoma following tuberculous pyothorax, when we see patients complaining of fever or chest pain with tuberculous pyothorax.

Androgen-dependent expression of fibroblast growth factor-1 in submaxillary gland of mouse

We have purified a 16,000 dalton protein that stimulates growth of human umbilical cord vein-derived endothelial cells (HUV-EC) from mouse submaxillary glands by using heparin-Sepharose affinity and C4 reverse phase chromatography. The purified molecule was identified as an FGF-1 on the basis of its biological activities, its affinity for heparin and its N-terminal amino-acid sequence. The concentrations of FGF-1 in the submaxillary gland of male or testosterone-treated female mice were about 12 times those of untreated females or castrated males. The 2.3 and 4.1 kb FGF-1 mRNAs were expressed in the glands of male mice older than 4 weeks but not in the glands of female mice. These results suggest that FGF-1 may have important functions for growth, differentiation and development of mouse submaxillary glands, and it may act as an endocrine hormone.

Identification of the chlB gene and the gene product essential for the light-independent chlorophyll biosynthesis in the cyanobacterium Plectonema boryanum

We cloned a 6.0-kb HindIII fragment from the cyanobacterium Plectonema boryanum using the chloroplast chlB (ORF513) gene of the liverwort (Marchantia polymorpha) as a probe. An open reading frame (ORF508) encoding a polypeptide of 508 amino acid residues was found within the nucleotide sequence of the 4,437-bp HindIII-EcoRV subfragment. The deduced amino acid sequence of ORF508 shows very high similarity to that encoded by the liverwort chlB gene (72.7%). A mutant, YFB14, in which ORF508 was inactivated by the insertion of a kanamycin-resistance cartridge, was unable to synthesize chlorophyll, accumulating protochlorophyllide in darkness while synthesizing chlorophyll normally in the light. Thus, the chlB gene is the third gene that is essential for the light-independent reduction of protochlorophyllide. The other two genes are chlL and chlN, and the results suggest that the light-independent protochlorophyllide reductase consists of at least three subunits, which are encoded by chlL, chlN and chlB. Using an antiserum prepared against a ChlB-6xHis fusion protein expressed in Escherichia coli, we detected a protein with an apparent molecular weight of 58,000 in the membrane fraction of the cyanobacterium. These results indicate that either the cytoplasmic or thylakoid membranes could be the site of the light-independent reduction of protochlorophyllide.

Long-term antiepileptic effects of chronic intake of CNK-602A, a thyrotropin-releasing hormone analogue, on spontaneously epileptic rats

Spontaneously epileptic rats (SER), which represent a double mutation (zi/zi, tm/tm), spontaneously exhibit both tonic and absence-like seizures. We examine the long-term effects of a thyrotropin-releasing hormone (TRH) analogue, CNK-602A, acute administration of which was effective inhibiting both types of seizures in SER, to determine if this agent could be used to treat epilepsy for long periods. Food pellets containing 0.001% CNK-602A were given ad libitum to SER from age 7 weeks. CNK-602A significantly inhibited tonic convulsions and prolonged survival. There were no alterations in body weight or plasma levels of triiodotHyronine (T3) and thyroxine (T4). These findings indicate that chronic intake of CNK-602A in a dose that does not affect plasma levels of T3 and T4 inhibits tonic convulsions in SER and suggest that this drug may be an effective treatment for convulsive seizures in patients with epilepsy.

Phosphorylation of Munc-18/n-Sec1/rbSec1 by protein kinase C: its implication in regulating the interaction of Munc-18/n-Sec1/rbSec1 with syntaxin

Munc-18/n-Sec1/rbSec1 interacts with syntaxin and this interaction inhibits the association of vesicle-associated membrane protein (VAMP)/synaptobrevin and synaptosomal-associated protein of 25 kDa (SNAP-25) with syntaxin. Syntaxin, VAMP, and SNAP-25 serve as soluble N-ethylmaleimide-sensitive fusion protein attachment protein (SNAP) receptors essential for docking and/or fusion of synaptic vesicles with the presynaptic plasma membrane. Genetic analyses in yeast, Caenorhabditis elegans, and Drosophila suggest that Munc-18 is essential for vesicle transport. On the other hand, protein kinase C (PKC) stimulates Ca2+-dependent exocytosis in various types of secretory cells. However, the modes of action of Munc-18 and PKC in vesicle transport have not been clarified. Here, we show that recombinant Munc-18 is phosphorylated by conventional PKC in a Ca2+- and phospholipid-dependent manner in a cell-free system. About 1 mol of phosphate is maximally incorporated into 1 mol of Munc-18. The major phosphorylation sites are Ser306 and Ser313. The Munc-18 complexed with syntaxin is not phosphorylated. The PKC-catalyzed phosphorylation of Munc-18 inhibits its interaction with syntaxin. These results suggest that the PKC-catalyzed phosphorylation of Munc-18 plays an important role in regulating the interaction of Munc-18 with syntaxin and thereby the docking and/or the fusion of synaptic vesicles with the presynaptic plasma membrane.

[Epidemiology of rotavirus infection in five different locations in the Asian area]

Between 1991 and 1994, serotypes and electropherotypes were determined for clinical specimens of group A human rotavirus (HRV) rotavirus collected from five different locations in the Asia, Saitama, Shizuoka, Taichung, Hong Kong, and Beijing. HRVs were detected through the year in Taichung and Hong Kong. The peaks of each rotavirus season were in January in Hong Kong, in March in Taichung, and in February and March in Saitama and Shizouka. We set one study year as that from July to next June. Serotype G1 was the most prevalent strain in the five different settings. Most of serotype G3 strains were identified in the study year 1991. Serotype G2 was the most predominant in Shizuoka and Taichung in the year 1993. Electropherotypes indicated the possible G types except in six cases of an unusual variant type whereas the serotype was G2 and the electropherotype was the "long" type. Five of the 502 cases and three of the 622 cases were identified as group C HRV by PAGE in Saitama and Shizouka respectively. In 216 samples in Taichung, no group C HRV strain was detected.

Chromatic regulation inChlamydomonas reinhardtii alters photosystem stoichiometry and improves the quantum efficiency of photosynthesis

The work addressed the adjustment of the photosystem ratio in the green algaChlamydomonas reinhardtii. It is shown that green algae, much like cyanophytes and higher plants, adjust and optimize the ratio of the two photosystems in chloroplasts in response to the quality of irradiance during growth. Such adjustments are compensation reactions and helpC. reinhardtii to retain a quantum efficiency of oxygen evolution near the theoretical maximum. Results show variable amounts of PS I and a fairly constant amount of PS II in chloroplasts and suggest that photosystem stoichiometry adjustments, occurring in response to the quality of irradiance during plant growth, are mainly an adjustment in the concentration of PS I. The work delineates chromatic effects on chlorophyll accumulation in the chloroplast ofC. reinhardtii from those pertaining to the regulation of the PS I/PS II ratio. The detection of the operation of a molecular feedback mechanism for the PS I/PS II ratio adjustment in green algae strengthens the notion of the highly conserved nature of this mechanism among probably all oxygen evolving photosynthetic organisms. Findings in this work are expected to serve as the basis of future biochemical and mutagenesis experiments for the elucidation of the photosystem ratio adjustment in oxygenic photosynthesis.

Analysis of T cell receptor beta chain repertoire in middle ear effusions

In order to elucidate the immune response in otitis media with effusion (OME), the polymerase chain reaction was employed to examine T cells in middle ear effusions in patients with OME for utilization of T cell receptor (TCR) variable region genes. Specimens of RNA were extracted from 13 ears of 12 patients (9 children and 3 adults). Oligonucleotide primers specific for individual TCR Vbeta gene families were used to amplify TCR gene products in each sample. Although the number of Vbeta families utilized by each sample varied from 1 family to 21, a few significant trends emerged. Eleven ears out of 13 expressed Vbeta7, which was the most frequently utilized (84.6%) Vbeta family among the 24 Vbeta families. In 5 of the 13 samples, the number of Vbeta families utilized was restricted to 1, which was Vbeta7 in all 5 samples. This result indicates the possibility that Vbeta7-bearing T cells in the middle ear are responding to a certain common antigen in some cases of OME.

Binding of Cd to metallothionein in the placenta of Cd-treated mouse

The toxicological significance of the placental metallothionein (MT) was studied from the viewpoint of cadmium (Cd) intoxication. The Cd concentration was higher in the placenta than the kidneys until 8 hr after a single injection of 109CdCl2, but was very low after administration of 109Cd-MT. Compared with lower doses, fetal Cd began to increase at the dose of 2 mg/kg. Alkaline phosphatase activity in the placenta was significantly decreased, and dead fetuses appeared at this dose. The MT concentration was not increased by the Cd injection but the ratio of Cd/Zn in MT increased proportionally to the dose up to 2 mg/kg. MT was detected in the placenta during all stages of pregnancy, and its concentration was higher in the earlier stage. The metal bound to MT was mainly Zn, and very little Cu was bound. In the mice that became pregnant after 109Cd accumulation, redistribution of 109Cd was not observed. MT-I and -II in the placenta were identified by column chromatography and immunoblotting methods. These findings suggest that the placental MT might play a protective role against Cd toxicity by trapping of the metal.

Decreased coronary blood flow is not responsible for myocardial dysfunction during bupivacaine-induced cardiotoxicity

BACKGROUND

Although previous studies have shown that bupivacaine produces a dose-dependent vasoconstriction, the possible effects of decreased coronary blood flow on myocardial dysfunction during bupivacaine-induced cardiotoxicity have not been investigated.

METHODS

We carried out the present study using the in situ beating hearts of six beagles. An autoperfusion circuit was established from the left carotid artery to the anterior descending coronary artery (LAD). Its blood flow (QLAD) was measured with an electromagnetic flow meter, and myocardial oxygen consumption was calculated using Fick's principle. Regional myocardial function (systolic shortening: %SS, post-systolic shortening: %PSS) of the LAD-supplied region was evaluated by the sonomicrometric technique. While saline or bupivacaine (10 micrograms/ml) was continuously infused into the LAD in a crossover design, the effects of a vehicle (baseline), acetylcholine (1 and 3 micrograms/min), nitroglycerin (10 micrograms/min) and adenosine (10 micrograms/min), on coronary haemodynamics and regional myocardial function were evaluated.

RESULTS

Bupivacaine caused a decrease in QLAD and regional myocardial dysfunction (a decrease in %SS and an increase in %PSS) at the baseline. While acetylcholine and adenosine increased QLAD with intracoronary bupivacaine-infusion, regional myocardial dysfunction was not reversed. There was a positive correlation between regional myocardial oxygen consumption and %SS in the whole study.

CONCLUSIONS

The results of this study indicate that the decrease in QLAD during bupivacaine-induced myocardial toxicity is not responsible for regional myocardial dysfunction, and, moreover, that it parallels a decrease in myocardial oxygen demand.

A mother and daughter with agenesis of the corpus callosum

A mother and daughter with agenesis of the corpus callosum are reported. There have only been 11 prior case reports of the familial occurrence of agenesis of the corpus callosum in the absence of extracranial malformations. Most of these reports have described familial occurrence among siblings. The present communication is only the second description of a parent and child with agenesis of the corpus callosum. A review of the published cases of familial syndrome unrelated agenesis of the corpus callosum indicates that both mental, developmental and neurologic disorders in cases involving parent and child are milder than those in cases involving siblings. Of additional interest, electroencephalography performed in this patient during sleep, frequently revealed bilateral asynchronous sleep spindles, supporting the hypothesis of previous investigators that the synchronicity of sleep spindles requires intact intercerebral commissures.

Deterioration of urinary findings after tonsil stimulation in patients with IgA nephropathy

We studied whether urinary findings are affected by stimulation of tonsils in patients with IgA nephropathy. In 62 patients with IgA nephropathy and 20 patients with other renal diseases tonsils were stimulated by an ultra short wave for 10 min. Changes in amount of urinary protein, urinary sediment, blood leucocyte count, concentrations of serum IgA and serum secretory IgA were evaluated after tonsil stimulation. Forty of 62 patients with IgA nephropathy (65%) showed deterioration of urinary findings after the stimulation compared with 6 of 20 patients with other renal diseases (30%). The deterioration was significantly more frequent in IgA nephropathy than in other renal diseases (p <0.005). Previous episodes of gross hematuria following upper respiratory tract infections had occurred in 17 of 40 patients who showed deterioration of urinary findings after tonsil stimulation (43%) as against in 4 of 22 without deterioration (18%). The level of serum secretory IgA was higher in patients who showed deterioration of urinary findings after tonsil stimulation than in those who did not show it. Though tonsil stimulation increased blood leucocyte count it did not affect the concentrations of serum IgA or secretory IgA. It is concluded that tonsil stimulation often deteriorates urinary findings in patients with IgA nephropathy; therefore chronic tonsillitis may play a part in the pathogenesis of IgA nephropathy.

[Blood pressure and renin in long-term hemodialysis patients]

Blood pressure (BP), plasma active renin concentration (ARC), plasma renin activity (PRA), aldosterone (Aldo), atrial natriuretic peptide (HANP), plasma sodium (Na), plasma potassium (K), total protein (TP), hematocrit (Ht) and body weight (BW) have been measured in 101 patients, including 9 diabetic patients, undergoing hemodialysis for 5 through 278 months. BP, ARC, PRA and HANP correlated inversely with the duration of dialysis. Among 13 patients undergoing hemodialysis for more than 20 years, only one patient received antihypertensive drugs. This finding suggested that relative low ability of renin secretion and a slightly low concentration of HANP causes low blood pressure in long-term dialysis patients. ARC was significantly correlated with PRA, Aldo, Na, TP-A (TP concentration after hemodialysis), Ht(delta)% (difference between before and after hemodialysis) and BW(delta)%. These investigations suggest that the removal of large quantities of water and salt in each dialysis session may cause excessive secretion of renin. Though no relation was demonstrated between ARC and blood pressure in 101 patients, ARC was correlated significantly with blood pressure in 37 non-DM patients undergoing hemodialysis for less than 10 years and was inversely correlated in 55 non-DM patients undergoing hemodialysis for more than 10 years. Therefore, further analysis of other factors that maintain blood pressure, especially in long-term dialysis patients is required. Multiple regression analysis showed that major factors regulating the levels of blood pressure were duration of dialysis, Ht(delta)% and BW(delta)%. During dialysis, we observed significant correlation between ARC(delta)% and Ht(delta)%, but we did not find any correlation between the change in blood pressure and ARC. Furthermore, [correction of Forthermore] we found that caution should be paid to body water control especially in diabetic patients, because of their remarkable fall of BP during dialysis.

Amrinone reverses bupivacaine-induced regional myocardial dysfunction

Amrinone has been shown to have therapeutic effects on bupivacaine-induced cardiovascular toxicity, but its exact effects on the heart are not well understood. This study evaluated the regional myocardial effect of amrinone on bupivacaine-induced cardiovascular toxicity in in situ beating hearts in 10 dogs using a selective coronary perfusion and sonomicrometry. In the control group, bupivacaine was administered into the left anterior descending coronary artery (LAD) for 15 min at four steps: baseline, step 1, step 2 and step 3, (calculated LAD plasma concentrations; 0, 5, 5 and 10 mu g center dot ml-1, respectively). In the amrinone group, amrinone (5 mu g center dot ml-1) was simultaneously infused at steps 2 and 3 in addition to bupivacaine infusions. Regional myocardial function of the LAD supplied area was evaluated by analysis of the left ventricular pressure-segment length loop. In the control group, systolic shortening decreased from the baseline (10.5 +/- 1.3%, mean +/- SEM) to step 3 (0.1 +/- 1.3%), and post-systolic shortening increased from the baseline (18.0 +/- 3.7%) to step 3 (52.3 +/- 5.5%) dose-dependently. In contrast, with amrinone infusion at steps 2 and 3, both variables returned to near baseline values. These results indicate that amrinone reverses bupivacaine-induced regional myocardial dysfunction.