Geosmin-producing Species of Coelosphaerium (Synechococcales, Cyanobacteria) in Lake Shinji, Japan

In Lake Shinji, Japan, periodic outbreaks of musty odour have occurred since mid-May 2007. Although the substance responsible for the odour was identified as geosmin, the odour-producing organism was unknown. We cultivated an axenic unialgal strain and determined that a species of Coelosphaerium (Synechococcales) was responsible for the production of geosmin in Lake Shinji. Our analysis was conducted using gas chromatography/mass spectrometry to determine the odorous compound. To determine the algae species, it was observed by optical microscopy to describe its morphological characteristics and the polymerase chain reaction was used to characterise the nucleotide sequence of the 16S rRNA gene and the 16S-23S rRNA internal transcribed spacer region. In addition, we explored the relationship between the number of cells of the Coelosphaerium sp. and the concentration of geosmin. In conclusion, geosmin, the cause of the musty odour in Lake Shinji in autumn 2009, was produced by Coelosphaerium sp., and to our knowledge, this is the first report of a geosmin-producing species in the family Coelosphaeriaceae.

[Chronic myeloid leukemia complicated with cerebellar hemorrhage and acute hydrocephalus successfully treated with imatinib and intensive supportive care]

We report a case of a 46-year-old female demonstrating general fatigue and visual disturbances with retinal bleeding. She had a white blood cell count of 419,300/mm. Thereafter, she developed vomiting associated with vertigo caused by cerebellar hemorrhage, deteriorating to acute hydrocephalus secondary to obstruction of the cerebral aqueduct. Emergency procedures for cerebral protection, such as hyperventilation, administration of mannitol, and barbiturate coma, were performed. Bone marrow examination showed a positive BCR-ABL/t(9;22)(q34;q11) chromosomal translocation detected by FISH and RT-PCR (masked Ph) and she was diagnosed as having chronic myeloid leukemia (CML) in the chronic phase (CP). She was administered Ara-C, together with imatinib 600 mg/d through a nasogastric tube. Eight days later, she underwent successful extubation and recovered without any neurological defect. She was maintained on imatinib 400 mg/d and demonstrated a major molecular response at 15 months. Physicians need to be aware that brain hemorrhage may develop as an initial symptom of CML patients in CP.

[Partial anomalous pulmonary venous connection to the high portion of the superior vena cava associated with ventricular septal defect repaired with williams method using right atrial flap: report of a case]

A 3-year-old boy suffered from the poor body weight gain under the diagnosis of partial anomalous pulmonary venous connection (PAPVC) to the high portion of the superior vena cava (SVC) associated with ventricular septal defect (VSD) and intact atrial septum (IAS). Preoperative cardiac catheterization revealed the pulmonary to systemic flow ratio 2.6 and mean pulmonary arterial pressure of 21 mmHg. He successfully underwent surgical repair with Williams method using right atrial (RA) flap out and VSD patch closure. Postoperative course was uneventful and echocardiography demonstrated no obstruction at the both routes of neo-SVC and neo-right upper pulmonary venous return.

[Surgical treatment for the patient with atrial septal defect and Andersen syndrome]

An 18-year-old girl with atrial septal defect and Andersen syndrome is reported. Andersen syndrome was described as a hereditary disease characterized by periodic paralysis, prolongation of the QT interval with ventricular arrhythmia and characteristic physical features including low set ear and micrognathia. We successfully performed cardiac operation for this rare associated malformation.

[Successful repair of supravalvular aortic stenosis using Steinberg 3 sinuses reconstruction; report of a case]

Steinberg method is a modification of Doty extended aortoplasty for supravalvular aortic stenosis (SAS). This modification entails placement of an additional patch in the left coronary sinus. A 3-year-old boy was diagnosed as SAS with aortic valvular stenosis. He was noticed a systolic murmur from 1 month after his birth. Echocardiography showed left ventricular hypertrophy, and pressure gradient of 80 mmHg was measured between the ascending aorta and the left ventricle. Cardiac catheterization revealed severe aortic stenosis at the sino-tubular (ST) junction. We adopted Steinberg 3 sinuses reconstruction. After this operation, there was no pressure gradient at ST junction although aortic valvular stenosis remained and mild aortic valve regurgitation newly developed. As this method can produce a symmetric aortic root, it may reduce aortic valve deformity especially on the left coronary cusp.

[Surgical treatment for postinfarction ventricular septal perforation]

Between November 1985 and April 2003, surgical treatment for ventricular septal perforation (VSP) after acute myocardial infarction was performed in 16 patients. Patients were divided into 2 groups by method of operation. One group is infarct exclusion technique (n = 10). The other group is trans right ventricular (RV) approach (n = 6). No significant differences were observed between 2 groups in preoperative states. Operative death rate was high in both groups. Five patients (50%) were died in infarct exclusion group, 4 patients (67%) in trans RV group. Infarct exclusion technique needed longer extracorporeal circulation time (201 +/- 33 min) than trans RV approach (170 +/- 32 min). Although trans RV approach is attractive for its simplicity, 3 cases died of rupture of remained left ventricle infarction area. On the other hand, there were no mortality cases caused by left ventricle rupture in infarct exclusion technique group. As this result, we select infarct exclusion technique as a surgical correction for VSP.

A simple and rapid in situ preconcentration method for the determination of phosphate in environmental waters by use of solid-phase extraction, and its applications to brackish lake waters

A simple and rapid in situ preconcentration method for the determination of phosphate in environmental waters has been developed for field analysis. This method is based on solid-phase extraction on a zirconium-loaded Sep-Pack Accell CM cartridge (Zr-SP) and is applicable to studies in which sampling is performed by use of a graduated syringe to prevent contamination and to ensure easy operation at sampling sites. The Zr-SP cartridge was prepared by passing 0.1 mol L(-1) zirconium solution through a Sep-Pak Accell CM cartridge, packed with cation exchange sorbent based on a silica matrix. The adsorption of phosphate and its desorption depend only on the pH of the solution. A water sample containing phosphate was adjusted to pH 2 and passed through the Zr-SP cartridge to collect it. The retained phosphate was quantitatively eluted with 0.5 mol L(-1) sodium hydroxide solution. The phosphate retained in the Zr-SP cartridge was stable for at least one month. The established preconcentration method was successfully applied to brackish lake waters to investigate seasonal changes in the distribution and behavior of phosphate in a brackish lake.

Somatic mutation of the hBUB1 mitotic checkpoint gene in primary lung cancer

Mutations in mitotic checkpoint genes have been detected in several human cancers, and these cancers exhibit chromosomal instability. Aneuploid stem cells seem to result from chromosomal instability and have been reported in many lung cancers. To determine whether alteration of mitotic checkpoint regulators is involved in carcinogenesis and tumor progression in primary lung cancer, we screened the genomic DNA sequence of 30 human lung cancer cell lines and 30 primary lung cancer tumors for a mutation in the hBUB1 mitotic checkpoint gene. First, we designed 26 sets of intron-based primers to amplify each of the 25 exons of the hBUB1 gene to examine the entire coding region of the hBUB1 gene. Using these primers, we performed polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis as well as direct sequencing in the mutation analysis of the hBUB1 gene. Three different nucleotide substitutions were detected in the coding region of the hBUB1 gene in some of the cancer cell lines and primary tumors as follows. The hBUB1 gene of one adenocarcinoma tumor contained a somatic missense mutation, a cytosine-to-guanine substitution in codon 51 of exon 5 that resulted in a histidine-to-aspartic acid amino acid substitution. The hBUB1 gene of three lung cancer cell lines contained a thymine-to-cytosine substitution in codon 430 of exon 12, which did not result in an amino-acid substitution. We were unable to determine whether the nucleotide substitution in exon 12 was a polymorphism or a silent mutation because matched normal tissue was not available. A polymorphism in codon 93 of exon 4, a guanine-to-thymine substitution, in hBUB1 was found in one lung cancer cell line and one primary lung tumor. This is the first report of a somatic missense mutation of a gene involved in a mitotic checkpoint in primary lung cancer. The presence of a point mutation in the hBUB1 gene is consistent with the hypothesis that alteration of mitotic checkpoint genes is involved in the development of primary lung cancers. Because the frequency of hBUB1 gene mutations was low, future studies should focus on other mechanisms of inactivation of the hBUB1 gene as well as mutation analysis of other mitotic checkpoint genes in lung cancers.

Iodine-123-iomazenil and iodine-123-iodoamphetamine SPECT in major cerebral artery occlusive disease

Iodine-123-iomazenil (IMZ) is a SPECT ligand for central-type benzodiazepine receptors, which are located only on neurons. We evaluated the feasibility of using IMZ SPECT for identifying neuronal damage in patients with the chronic phase of thrombotic cerebral ischemia.

METHODS

We studied 15 patients with angiographically-confirmed unilateral severe occlusive lesions (occlusion or > 70% stenosis) in the carotid system. IMZ SPECT images obtained 180 min after injection of 167-222 MBq IMZ were analyzed. The regional cerebral blood flow and perfusion reserve were evaluated for comparison with IMZ SPECT findings, using the split-dose 123I-iodoamphetamine (IMP) SPECT method, coupled with intravenous injection of 1 g acetazolamide. On both SPECT images, the count ratio of the affected to the nonaffected whole MCA territory (A/NA ratio) and of the contralateral to the ipsilateral cerebellar cortex (C/I ratio) were determined.

RESULTS

The A/NA ratio with IMZ was significantly higher than that with IMP (94.5% +/- 6.2% versus 91.4% +/- 6.6%, p < 0.005), although a significantly positive correlation was found between these two ratios (r = 0.854, p < 0.0001). The C/I ratio with IMP was decreased significantly in 5 patients compared with that in normal subjects, whereas the C/I ratio with IMZ was decreased in only 1 patient. There was no significant correlation between the A/NA ratio with IMZ and the perfusion reserve in the affected MCA territory. In 2 of 5 patients with a decreased A/NA ratio (<90%) with IMZ, decreased blood flow with preserved perfusion reserve and cerebral hemispheric atrophy were observed, which suggested the influence of neuronal loss due to chronic ischemia.

CONCLUSION

These findings indicate that IMZ SPECT, which provides new information regarding neuronal damage after ischemic insult to the brain, is useful for evaluating thrombotic cerebral ischemia.

SPECT findings in mitochondrial encephalomyopathy

We investigated the alterations in regional cerebral blood flow (rCBF) in mitochondrial encephalomyopathy (MEM), using [123I]N-isopropyl-p-iodoamphetamine (IMP) or 99mTc-hexamethyl propyleneamine oxime SPECT in 10 MEM patients.

METHODS

Four of the patients had MEM with lactic acidosis and strokelike episodes (MELAS), 2 had Kearns-Sayre syndrome (KSS), 1 had myoclonic epilepsy with ragged red fibers (MERRF) and 3 had cytochrome C oxidase deficiency (CCOD). Cerebral perfusion reserve was obtained from 6 patients (3 MELAS, 1 MERRF, 1 KSS, 1 CCOD) for a comparative analysis using the split-dose 123I-IMP SPECT method before and after the injection of acetazolamide.

RESULTS

All patients with MELAS showed focal hypoperfusion in the parietal and/or occipital lobes. Follow-up studies (3 MELAS patients) revealed extension or improvement in the abnormal perfusion. The hypoperfused lesions were correlated with abnormal CT/MRI findings. Perfusion was normal in 1 MERRF, 2 KSS and 3 CCOD patients, whereas CT/MRI findings in 1 MERRF, 1 KSS and 1 CCOD patient were abnormal. The cerebral perfusion reserve in 3 MELAS patients was decreased significantly compared with that in patients with other types of MEM (MELAS 7.4%, other MEM 33.8%; p < 0.05).

CONCLUSION

The rCBF was altered specifically in patients with MELAS, suggesting that brain perfusion SPECT will be useful in diagnosing and assessing such patients. The decreased cerebral perfusion reserve in patients with MELAS may represent an important feature of the pathogenesis of the strokelike episodes. The SPECT findings of patients with other types of MEM (MERRF, KSS and CCOD) were normal.

[Obesity as one of the risk factors for urolithiasis]

BACKGROUND

It is well known that many diseases may be associated with obesity resulting from an energy-rich diet, and that a westernized diet may increase the incidence of urinary stone formation. To evaluate degree of obesity, we investigated body mass index (BMI) in patients with calcium containing upper urinary stones and examined their blood with regard to lipid metabolism.

METHODS

Between July 1994 and December 1995, we analyzed 332 fresh renal-stone formers (253 males and 79 females) who visited 7 hospitals located in Ehime prefecture. As a control, 949 residents older than 20 years (387 males and 562 females) of the same prefecture were also examined by the annual Ehime prefecture office report of 1994. Body mass index as degree of obesity, stone-recurrence, blood test and other complicated diseases were examined.

RESULTS

In male stone formers the rate of obesity was significantly higher than that of control males (p < 0.001). The differences were seen only in their twenties and fifties. Furthermore, among male stone formers the rate of obesity was significantly higher in recurrent stone formers than in single stone formers (p < 0.05). On the other hand, in female, there was no significant difference in the rate of obesity between stone formers and controls. No difference was seen between recurrent stone formers and single stone formers. In the blood test, there was no differences in the level of calcium, phosphate and uric acid between stone formers and controls. The level of cholesterol and triglyceride in male were significantly higher in controls (p < 0.01) and there was no difference in the level of high density lipoprotein (HDL) between stone formers and controls. Among the stone formers, 48 males (20.0%) and 17 females (21.5%) had other diseases. The rate of complicated diseases was similar to that of controls and no specific diseases in the stone formers were identified.

CONCLUSION

Our report suggested that obesity in male should be considered as a risk factor for calcium containing stone formation.

Hemodynamic aspect of cerebral watershed infarction: assessment of perfusion reserve using iodine-123-iodoamphetamine SPECT

The mechanism whereby watershed (WS) infarcts develop remains controversial, although a hemodynamic cause is usually assumed. The aim of this study was to investigate the relationship between the site of WS infarcts and the hemodynamic status of the cerebral circulation.

METHODS

From among 96 consecutive patients with angiographically confirmed unilateral major cerebral artery obstruction (occlusion or > 70% stenosis), we investigated 29 patients with supratentorial WS infarcts on magnetic resonance imaging. The regional cerebral blood flow and perfusion reserve were quantified using the split-dose [123I]iodoamphetamine SPECT method, coupled with intravenous injection of 1 g of acetazolamide. Seven patients had a cortical WS infarct between the superficial branches of the anterior and middle cerebral arteries (MCAs) or between the middle and posterior cerebral arteries (Group C), and 22 had a deep WS infarct between the superficial branches and deep penetrating arteries of the MCA (Group D). Moreover, the patients in Group D were classified into two subgroups, i.e., Type A (n = 12), with lesions lying in the centrum semiovale above the level of the lateral ventricles, and Type B (n = 10), with lesions lying in the corona radiata adjacent to the lateral ventricles.

RESULTS

Comparison of the Type of WS infarct with the clinical course of onset showed that sudden onset was more frequent in Group C than in Group D (p < 0.05). The perfusion reserve in the affected MCA territory in Group D (20.1% +/- 15.6%) was significantly lower than that in Group C (43.8% +/- 10.8%; p < 0.01) and that in 20 hemispheres (10 control subjects) without a major arterial lesion (54.7% +/- 16.4%; p < 0.01). Among the Group D patients, the patients with Type A infarcts showed a significantly lower perfusion reserve compared with those with Type B infarcts (p < 0.05).

CONCLUSION

Patients with deep WS infarcts, especially Type A infarcts, showed severe hemodynamic impairment, whereas patients with cortical WS infarcts showed preserved perfusion reserve which appeared to be secondary to the embolism. The mechanism of development of WS infarcts is multifactorial, and distinguishing among these WS infarcts and from other types of infarct is important, because different pathogenic mechanisms require different therapeutic strategies.

Intra-individual differences between technetium-99m-HMPAO and technetium-99m-ECD in the normal medial temporal lobe

Regional distributions of 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) and 99mTc-ethyl cysteinate dimer (99mTc-ECD) were compared in the normal brain.

METHODS

Six paid, healthy volunteers (mean age 26 yr) had high-resolution neuroperfusion SPECT using both 99mTc-HMPAO and 99mTc-ECD on separate days.

RESULTS

Regional distribution of the two tracers differed. Technetium-99m-HMPAO accumulated more in the thalamus, frontal lobe, temporal lobe and cerebellum than 99mTc-ECD, which accumulated more in the occipital and parietal lobes. There was a considerable difference in the accumulation of the two tracers in the medial temporal lobe. The percent accumulations of 99mTc-HMPAO and 99mTc-ECD in the medial temporal lobe compared with the mean global cerebral cortical accumulation were 93.9% +/- 2.4% and 83.1% +/- 4.1% (mean +/- s.d.), respectively.

CONCLUSION

The results suggest that 99mTc-HMPAO and 99mTc-ECD require specific and separate criteria for diagnosing temporal lobe pathologies, such as dementia and temporal lobe epilepsy.

Comparison of iodine-123-iomazenil SPECT and technetium-99m-HMPAO-SPECT in Alzheimer's disease

This study was designed to elucidate a central type of benzodiazepine (Bz) receptor distribution in patients with Alzheimer's disease using SPECT with [123I]iomazenil (IMZ).

METHODS

Eight patients with probable Alzheimer's disease were studied. Benzodiazepine receptor imaging was performed 15 min (early) and 180 min (delayed) after intravenous administration of 167 MBq IMZ, sequentially, using hexamethylpropylene amine oxime (HMPAO) SPECT to evaluate regional cerebral perfusion.

RESULTS

Early IMZ-SPECT depicted areas of reduced uptake in sites of decreased cerebral blood flow (CBF), but each area of decreased uptake was extended wider than the area of hypoperfusion. Delayed IMZ-SPECT images demonstrated a similar pattern of decreased area of CBF; the affected region in Bz receptor bindings, however, was clearer and broader compared with that in either HMPAO-SPECT or early IMZ-SPECT. In comparison with the uptakes for the normal cerebral hemisphere (ratio to the contralateral cerebellum) in patients with unilateral cerebral infarction as a control group (n = 4), the patients with Alzheimer's disease showed distinctive bilateral frontal or parietal defects (p < 0.05).

CONCLUSION

Brain SPECT using IMZ may be more sensitive than CBF images in patients with Alzheimer's disease.

[Evaluation of 123I-iomazenil SPECT in patients with ischemic cerebrovascular disease: comparative study with 123I-IMP SPECT]

Clinical evaluation of 123I-iomazenil, a new imaging agent for central-type benzodiazepine receptors with SPECT, was performed in patients with ischemic cerebrovascular disease. We investigated 15 patients with angiographically-proven severe occlusive lesions (occlusion or > 70% stenosis) in the unilateral carotid system. 123I-iomazenil SPECT images were compared with cerebral blood flow (CBF) images and the cerebral perfusion reserve, which were measured using the "split dose 123I-IMP SPECT method" before and after the intravenous injection of 1 g of acetazolamide. For the detection of ischemic lesions, CBF images were superior to 123I-iomazenil images based on visual analysis. Regarding the count ratio of the affected MCA territory to the non-affected (L/N), 123I-IMP was lower than 123I-iomazenil in most of the cases. In five patients showing "crossed cerebellar diaschisis" by 123I-IMP, asymmetry of the cerebellar accumulation was observed in only one patient with 123I-iomazenil, which was less prominent than with 123I-IMP. There was no significant correlation between the L/N ratio with 123I-iomazenil and the cerebral perfusion reserve in the affected MCA territory. However, in some cases showing a decreased L/N ratio (< 90%) with 123I-iomazenil, a decreased CBF with normal perfusion reserve and cerebral hemi-atrophy were observed with 123I-IMP and MRI, which suggested the influence of neuronal loss due to chronic ischemia. These results indicate that 123I-iomazenil SPECT, which provides new information regarding neuronal loss due to ischemic damage to the brain, is useful for the evaluation of ischemic cerebrovascular disease.

Super-early iodine-123-iodoamphetamine SPECT imaging of human primary motor cortex

This study was designed to visualize the motor function area related to finger movements in normal human brain using super-early (first 640 sec of acquisition) [123l]iodoamphetamine ([123I]IMP) SPECT.

METHODS

Seven healthy male volunteers performed paired, isolated baseline and task sessions. The task was a right thumb-to-fingers opposition task, which was loaded for the initial 11 min of the session. A high-performance, four-head SPECT camera was used. At each session, administration of 222 MBq [123I]IMP was followed by 16 serial 160-sec dynamic SPECT acquisitions. To obtain matched brain anatomical images, MRI was also performed using the same slice formation as in the SPECT study. After image reconstruction, ROIs were set on bilateral sensorimotor hand areas (SMHA), the supplementary motor area (SMA), the frontal, temporal and occipital lobes and the cerebellar hemispheres. The percent increase of ROI activity (%INC) in the task session compared with that in the baseline session was calculated in each ROI after normalization to the global brain radioactivity.

RESULTS

There was significant activation of the left SMHA by the task, the amplitude of which was maximal in the initial phase of dynamic images (the super-early phase). This area was located in the left peri-central area identified on the analogous slice in the MR image. The left SMHA showed gradual and statistically significant decrease of %INC during the three phases.

CONCLUSION

Super-early [123I]IMP may be used to identify the primary motor cortex and to evaluate its function in some pathological conditions.

Three-dimensional display of surface cortical perfusion by SPECT: application in assessing Alzheimer's disease

To better understand cortical perfusion, we developed a method for a three-dimensional display technique with 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT.

METHODS

Twelve patients with higher cortical dysfunction due to Alzheimer's disease and 18 age-matched controls were examined. Data acquisition was performed after intravenous injection of 740 MBq of 99mTc-HMPAO. After reconstructing the transaxial images, the three-dimensional images were obtained by modified volume rendering, where the surfaces were displayed in the corresponding colors as the maximum cortical value within a depth of 2 cm.

RESULTS

In the control studies, almost all surface cortices were over 60% of the maximum cerebellar value. In Alzheimer's disease patients, areas of perfusion below 60% were detected in the temporo-parietal lesions and frontal lobe lesions in 6 of 12. These findings correlated with the neurological dysfunction.

CONCLUSION

This method provides realistic three-dimensional information about surface cortical perfusion, which was found to be useful in clinical investigations of higher cortical dysfunction due to degenerative or cerebrovascular diseases.

Carbon dioxide reactivity by consecutive technetium-99m-HMPAO SPECT in patients with a chronically obstructed major cerebral artery

In the management of major cerebral artery obstruction, cerebral perfusion reserve is key to introducing cerebral revascularization surgery. The purpose of this study was to evaluate the feasibility of assessing cerebral perfusion reserve by consecutive 99mTc-hexamethyl-propyleneamine oxime (99mTc-HMPAO) SPECT with 5% carbon dioxide (CO2) inhalation.

METHODS

The CO2 inhalation and consecutive 99mTc-HMPAO SPECT study was performed on 30 chronic ischemic cerebrovascular disease patients with unilateral major cerebral artery obstruction and on 27 patients without. CO2 reactivity was expressed as the percent increase of 99mTc-HMPAO accumulation from the baseline (%Change) and as a constant k' that was the ratio of 99mTc-HMPAO accumulation per 1 mmHg change of end-tidal CO2 tension by exponential curve fitting.

RESULTS

The mean %Change and k' in the middle cerebral artery (MCA) territory on the side without an obstructive lesion or in the cerebellum ranged from 10.0% to 11.1% and from 0.98% to 1.13% per mmHg, respectively. In the MCA territory, an obstructive lesion was noted in 5.9% versus 0.54% per mmHg in the contralateral MCA territory (p < 0.01). Eleven of 30 patients with major cerebral artery obstruction revealed significant asymmetry in the k' value between bilateral MCA territories.

CONCLUSION

The results showed compromised cerebral perfusion reserve in the obstructed major cerebral artery territory. The present method was proven clinically useful for evaluating cerebral perfusion reserve in patients with unilateral major cerebral artery obstruction.

[A case of double neoplasms--small cell carcinoma in the mediastinum and squamous cell carcinoma of the esophagus]

A 62-year-old Chinese man was admitted to our hospital because of dysphagia and hoarseness. Chest X-rays showed a superior mediastinal mass, and an operation for the removal of this mediastinal tumor was performed. The histological diagnosis indicated a small cell carcinoma, probably arising from the lung. He was readmitted to our clinic one year later with a complaint of dysphagia due to an esophageal cancer. Radical surgery for the esophageal cancer was performed, and the histological findings showed a well differentiated squamous cell carcinoma. The histogenesis of this carcinoma was considered to be independent of the earlier mediastinal tumor.

Anti-acetylcholine receptor antibody titer with extended thymectomy in myasthenia gravis

Twenty-four patients with myasthenia gravis of Osserman's generalized type underwent extended thymectomy through a sternal-splitting approach. Their clinical responses to thymectomy and postoperative changes in anti-acetylcholine receptor antibody titers were evaluated. The follow-up time ranged from 1 month to 7 years and 7 months (average, 36 months). Six patients (25%) had remissions and 17 patients (71%) were improved after operation. The preoperative anti-acetylcholine receptor antibody titers dropped significantly after operation (p less than 0.001). The postoperative reduction in these titers correlated with the time course after operation (p less than 0.05). Their postoperative reduction was significantly greater in the six patients having remissions than in the 15 having marked (p less than 0.02) and the six having moderate improvement (p less than 0.005). This study has revealed that anti-acetylcholine receptor antibody titer in plasma declines progressively after thymectomy, and the postoperative reduction of this titer correlates with the clinical effect of thymectomy.

Reoperation after transcervical thymectomy for myasthenia gravis

Among 137 thymectomized patients with nonthymomatous myasthenia gravis (MG), six were reoperations. Thymectomy had initially been performed by the transcervical approach, but was ineffective. Extended thymectomy was then performed by median sternotomy. The reoperations revealed residual thymus (average weight, 19 gm) in all cases. Postoperative courses were favorable in three patients and unfavorable in three others. The latter had received high-dose steroid therapy before the second operation. We conclude that total thymectomy by the transcervical approach is almost impossible, and that reoperation may accelerate improvement in some cases.

Spontaneous remission of myasthenia gravis in patients with thymoma

In 42 cases of myasthenia gravis with thymoma, the tumor was removed surgically. In four of these cases, myasthenic symptoms had remitted before operation. However, in two of these four cases, myasthenic symptoms returned after operation, despite apparently total thymectomy. In two of the four cases that remitted before operation, the thymus was found to be highly involuted, without germinal centers; in another case, the thymus was found to be moderately involuted, and germinal centers were found. In the nonrelapsing cases, only the tumor itself was removed, with residual thymic tissue being left behind. The thymoma in all cases consisted of polygonal epithelial cells and lymphocytes.

Study on the ratio of lymphocytes to epithelial cells in thymoma

In order to quantify the lymphocyte to epithelial cell ratio (L/E ratio of the thymoma, actual counting was performed. The L/E ratio was investigated in 25 specimens of 22 cases (22 initial tumors and 3 recurrent tumors). L/E ratios ranged from 0.27 to 4.10, and the mean value was 1.93 +/- 0.21. The mean L/E ratio of histologically malignant group was lower than that of the benign group. In the three recurrent cases, L/E ratios of the recurrent tumor decreased in all cases. It was concluded that the epithelial element increases with the adva