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Biomedical subjects

H Tsuji

Publications and source records attributed to H Tsuji.

At least 217 records · Page 12Linked to original sources
PubMed1997

Lumbar intervertebral disc herniation in children less than 16 years of age. Long-term follow-up study of surgically managed cases.

STUDY DESIGN: In this retrospective study, the long-term clinical results of lumbar intervertebral disc herniation in children less than 16 years of age were reviewed. OBJECTIVES: To evaluate the effectiveness of surgical treatment including posterior discectomy, extraperitoneal anterolateral discectomy, and anterior interbody fusion for lumbar intervertebral disc herniation in children less than 16 years of age. SUMMARY OF BACKGROUND DATA: Although previous follow-up studies on surgically managed lumbar intervertebral disc herniation in children and adolescents generally reveal good outcomes, few reports have focused on the time course of clinical findings and the long-term results. METHODS: The outcome of subjective symptoms, clinical signs, and time-related change of the intervertebral disc space in 11 patients were evaluated with an average follow-up period of 9 years (range, 5-12 years). RESULTS: The posterior discectomy procedure relieved clinical symptoms quickly. In the case of central herniation with or without intervertebral instability, extraperitoneal anterolateral discectomy or anterior interbody fusion led to favorable long-term results. Clinical symptoms (lower back pain, leg pain) and neurologic disturbance disappeared within 3 months after surgery. Recovery of normal straight leg raising test results (tight hamstrings), however, required much more time than recovery of other symptoms. Narrowing of the intervertebral disc space progressed up to 3-6 months after discectomy, but then disc space widening occurred. CONCLUSIONS: Satisfactory long-term clinical results and early return to school life were obtained with each surgical procedure. It is important to aim toward an early return to school via surgical treatment.

Adolescent↗
PubMed1997

Radiographic classification of Os odontoideum and its clinical significance.

STUDY DESIGN: This study analyzed the relationship between the configuration of the atlantoaxial joint and the clinical characteristics of patients with os odontoideum. OBJECTIVES: To compare three types of atlantoaxial configurations of os odontoideum from the viewpoint of clinical characteristics. METHODS: Twelve patients were classified into the following three types according to their atlantoaxial configuration on an anteroposterior radiogram: round (n = 6), cone (n = 4), and blunt-tooth (n = 2). Clinical features in each group were compared in terms of mean age, gender distribution, severity and type of myelopathy, and degenerative findings of the atlantoaxial joint. RESULTS: The patients in the round type group were predominantly women and had more severe myelopathy than that of patients in the other groups. According to Crandall's classification of myelopathy, all patients showed the transverse lesion syndrome in the cone and blunt-tooth types. Four of six patients with the round type of atlantoaxial configuration had the Brown-Séquard syndrome. With the round type, it appeared that the lateral mass of the axis tended to dislocate laterally, and this lateral instability associated with anteroposterior instability was believed to induced the Brown-Séquard syndrome. CONCLUSIONS: Myelopathy in patients in the round type group was the most severe compared with that of patients in the other three groups. This classification is considered useful for estimating clinical findings in os odontoideum.

Adolescent↗
PubMed1997

Hypertrophic spinal pachymeningitis. A case report.

STUDY DESIGN: This is a case report and review of the literature. OBJECTIVE: To describe the clinical findings and the surgical treatment of a 28-year-old man with hypertrophic spinal pachymeningitis in the thoracic and lumbar region managed by expansive laminoplasty. SUMMARY OF BACKGROUND DATA: Hypertrophic spinal pachymeningitis is extremely rare. No description of findings present after expansive laminoplasty for hypertrophic spinal pachymeningitis has been reported. METHODS: The clinical findings, course, and surgical treatment of a 28-year-old man with a hypertrophic spinal pachymeningitis are presented. The patient required expansive laminoplasty. The follow-up period after the surgical procedure was 4.2 years. RESULTS: An unusual etiology of spinal cord compression by thickened dura mater was found with a contrast ring- or crescent-shaped enhancement on gadopentetate magnetic resonance imaging. Spasticity disappeared after the patient underwent expansive laminoplasty. CONCLUSION: This is the first report of a patient with hypertrophic spinal pachymeningitis treated with expansive laminoplasty. Spinal canal decompression and autogenous bone grafting are accepted treatments in the young patient. Careful observation of the patient to watch for local progression is necessary.

Adult↗
PubMed1997

Cloning and sequencing for the largest subunit of Chinese hamster RNA polymerase II gene: identification of a mutation related to abnormal induction of sister chromatid exchanges.

In order to analyze the mutation sites related to abnormal induction of sister chromatid exchanges (SCEs) in the RNA polymerase II largest subunit (RpII LS) gene of the Chinese hamster CHO-KI cell mutant, we have completely sequenced the whole region of the RpII LS cDNAs obtained from normal and mutant cells. By comparing both sequences, a mutation that results in an amino acid (aa) change in the RpII LS gene was found. This aa change was Pro (CCC) to Ser (TCC) at position 1006. Multiple alignment for aa sequences of RpII LS from various species revealed that this Pro residue was highly conserved throughout the eukaryotes. Considering the differences in physico-chemical properties between Pro and Ser residues, the Pro-->Ser substitution may alter the RpII LS structure.

Amino Acid Sequence↗
PubMed1997

Risk indicators of low back pain among workers in Japan. Association of familial and physical factors with low back pain.

STUDY DESIGN: A questionnaire was given to 3,042 Japanese workers at a factory in 1992. It surveyed age, gender, weight, height, job classification, and work environment, as well as the perceived causes, onset age, and characteristics of low back pain. Family history of low back pain among first-degree relatives and perception of physical condition also were assessed. OBJECTIVES: To investigate the risk indicators of low back pain in Japanese workers with various kinds of job classifications in a manufacturing company. SUMMARY OF BACKGROUND DATA: Risk indicators of low back pain in Japanese patients have not been fully investigated in previous studies. METHODS: Prevalence rates and characteristics of low back pain were examined among 3,042 factory workers (2,517 men and 525 woman) with jobs with varying physical demands. In the analysis of risk indicators of low back pain, the odds ratios and 95% confidence intervals were computed. In addition, a multiple logistic analysis was performed to evaluate risk indicators of low back pain. RESULTS: Point and lifetime prevalence of low back pain were correlated with the physical demands of the job. The perceived cause found to be most associated with low back pain were lifting in workers with jobs requiring moderate to heavy work and sports activity in sedentary workers. Family history of low back pain in parents, siblings, and children was a risk indicator of low back pain. The average age of the first attack of low back pain in workers with a family history of it in their parents was significantly younger than that in workers with no family history in a multiple logistic analysis in male workers, the physical work demands, age, and family history of low back pain in their parents were risk indicators; however, obesity was not a risk indicator. Physical and mental conditions of workers also were associated with low back pain. CONCLUSIONS: The physical job demands show a clear association with the point and lifetime prevalence of low back pain, and improvements in work conditions may decrease low back symptoms among workers. It is likely that a family history of low back pain and physical and mental conditions of workers also should be considered in the management of low back pain.

Adult↗
PubMed1997

Cartilage and subchondral bone interaction in osteoarthrosis of human knee joint: a histological and histomorphometric study.

The present study has focused on the cartilage-bone interrelationships in the progression of osteoarthrosis in human knees. Eleven tibial condyles with osteoarthrosis were analyzed by histology and bonemorphometry. The data were evaluated according to the grade of joint cartilage degeneration in distinct areas of the tibial condyle. The bone morphometric data were also analyzed by the depth of subchondral bone. A parallel relationship between the bone volume/bone formation activity and the Mankin's grade of cartilage degeneration was observed in both medial and lateral condyles. In the lateral condyle, there was correlation among progression of cartilage degeneration and trabecular and osteoid thickness and bone formation activity. Osteoblasts and osteoclasts were most abundant in the external areas of the medial condyles. Bone resorption activity in the medial condyle was found only in the external and intermediate areas, but it was extremely low in all areas of the lateral condyle. The values of bone volume in relation to depth were highest in the superficial layer with a decrease as the depth increased in both condyles. The bone formation activity was high in the superficial layer of the lateral condyle, whereas in the medial condyle, it was high in the layer between 500 and 1,500 microns of depth. The bone volume and bone formation activity were higher in all layers of the medial condyle in comparison with the lateral condyle. The bone resorption activity was low in the superficial layer of the medial condyle as compared with deeper layers. These results suggested that the joint cartilage degeneration is influenced by the remodeling of the underlying subchondral bone.

Aged↗
PubMed1997

Effects of hydrostatic pressure on matrix synthesis and matrix metalloproteinase production in the human lumbar intervertebral disc.

STUDY DESIGN: This study is a unique in vitro study on the effects of hydrostatic pressure on human intervertebral disc metabolism. OBJECTIVE: To investigate the effects of hydrostatic pressure on matrix synthesis and matrix metalloproteinase production in the human lumbar intervertebral disc. SUMMARY OF BACKGROUND DATA: Mechanical stress and hydrostatic pressures influence proteoglycan and protein synthesis rates in bovine articular cartilage and coccygeal discs. However, the mechanism of matrix synthesis regulation of the intervertebral disc under mechanical stress has not been elucidated. METHODS: Twenty-eight human lumbar intervertebral discs obtained from surgery and from cadavers at autopsy were used. Each tissue fraction was charged with medium in a plastic syringe and placed in a water-filled hydrostatic pressure-control vessel. The hydrostatic pressures applied were 1 (control), 3, and 30 atm (atm = atmospheres) for 2 hours. The proteoglycan and protein synthesis rates were determined by radioisotope incorporation. The production of matrix metalloproteinase-3 and tissue inhibitor of metalloproteinases-1 were measured by a one-step enzyme immunoassay method using monoclonal antibodies. RESULTS: Three atm pressure stimulated proteoglycan synthesis rates in the nucleus pulposus and inner anulus (n = 14 in each tissue). Compared with the control group, 30 atm pressure significantly inhibited proteoglycan synthesis in the inner anulus (P = 0.011). In the nucleus pulposus, matrix metalloproteinase-3 production was stimulated at a pressure of 30 atm relative to 3 atm (P = 0.014, n = 16 in each tissue). The highest tissue inhibitor of metalloproteinases-1 production showed highest values at 3 atm pressure in the inner anulus (n = 16 in each tissue). CONCLUSION: The results suggest that hydrostatic pressure influences intervertebral disc cell metabolism. A physiologic level of hydrostatic pressure (3 atm) may act as an anabolic factor for stimulation of proteoglycan synthesis and tissue inhibitor of metalloproteinases-1 production. This may be essential for maintaining the matrix of the disc. If the pressure was 30 atm or more or 1 atm or less, a catabolic effect will be predominant, with reduction of proteoglycan synthesis rate and increase of matrix metalloproteinase-3 production. Abnormal hydrostatic pressure, therefore, may accelerate disc degeneration.

Cadaver↗
PubMed1997

Postlaminectomy adhesion of the cauda equina. Changes of postoperative vascular permeability of the equina in rats.

STUDY DESIGN: The authors evaluated the vascular permeability changes of the cauda equina after lumbar laminectomy in rats. OBJECTIVES: To clarify the early vascular responses in postlaminectomy adhesive arachnoiditis. SUMMARY OF BACKGROUND DATA: Laminectomy-induced cauda equina adhesion has been visualized by postoperative serial magnetic resonance imaging in humans. In laminectomized rats, fibrinous exudation was apparent among the adhered cauda equina. To date, there has been no report of substantial changes in vascular permeability in the cauda equina after lumbar laminectomy. METHODS: Wistar rats laminectomized from L5-L6 were used for four studies; 1) Evans blue albumin tracer study; 2) horseradish peroxidase tracer study; 3) lanthanum tracer study; and 4) fluoroscein isothiocyanate-dextran (molecular weights: 20K, 70K, and 150K) tracer study. Untreated rats were used as controls. RESULTS: 1) In the laminectomized (L5-L6) area, the cauda equina tended to conglomerate from 3 hours after surgery; this was relatively resolved by 6 weeks. Extravascular leakage of Evans blue albumin in the cauda equina appeared at 3 hours after surgery and reached a plateau at 24 hours; it mostly disappeared by 6 weeks. At 24 hours after surgery, the extent of Evans blue albumin extravasation was seen in one or more levels adjacent to the laminectomized area. Evans blue albumin leakage and cauda equina adhesion started to appear in nearly a same phase after laminectomy, followed by a plateau of vascular permeability facilitating complete cauda equina adhesion by 24 hours after surgery. The restoration of Evans blue albumin leakage was noted 1 week after surgery, and tended to precede recovery of the cauda equina adhesion; 2) in the laminectomy group, Horseradish peroxidase penetrated from the lumen to the extracellular space beyond the basal laminae of the endothelial cells. Numerous horseradish peroxidase-labeled vesicles in the endothelial cells were found; 3) There was a significant increase in lanthanum distribution in the endothelial cytoplasm at the laminectomized levels. Lanthanum filled the interendothelial clefts beyond the tight junction, but did not penetrate through the perivascular basal laminae; 4) Fluoroscein isothiocyanate-dextran (20K, 70K, 150K) permeability increased in the laminectomy group, but there was no difference in extravasation of fluoroscein isothiocyanate-dextran, irrespective of the molecular weight. CONCLUSION: Laminectomy consistently induced an increase in vascular permeability in the cauda equina, an increase of vesicular transport in the endothelial cell, and opening of the tight junction early after laminectomy, suggesting breakdown of the blood nerve barrier in the cauda equina. The accelerated permeability may enhance cauda equina adhesion.

Animals↗
PubMed1997

Radiation tolerance of cirrhotic livers in relation to the preserved functional capacity: analysis of patients with hepatocellular carcinoma treated by focused proton beam radiotherapy.

PURPOSE: To determine the preserved functional capacity of the liver as a probable determinant of radiation tolerance in patients with cirrhosis and hepatocellular carcinoma, who underwent proton beam radiotherapy. MATERIALS AND METHODS: We reviewed computed tomographic (CT) scans of 26 patients with cirrhosis and hepatocellular carcinoma during a period of 12-27 months after proton beam radiotherapy. Tumors were treated with focused proton beams with target doses of 140-186 TDF (time, dose, and fractionation). We measured the degree of hypertrophy of the untreated liver volume by measuring the total liver volume and the treated liver volume which was radiologically identified on contrast-enhanced CT scans. The risk of radiation-induced liver failure was estimated using the prediction score (PS) originally used for estimating posthepatectomy liver failure, substituting the planned treated liver volume for the resection liver volume. RESULTS: The degree of hypertrophy ranged from -19% to 51%, and was significantly positively correlated with the ratio of the planned treated liver volume to the functional liver volume. The PS agreed well with observed radiation tolerance in 21 patients, but underestimated the tolerance in 5. This underestimation was diminished when the PS was recalculated using the identified untreated liver volume in lieu of the planned untreated liver volume. CONCLUSION: As in surgical treatment, radiation tolerance of the cirrhotic liver after focused treatment is closely related to the preserved functional capacity of the identified untreated liver volume, which shows compensatory hypertrophy following radiotherapy.

Aged↗
PubMed1997

Changes in serum creatine phosphokinase MM isoenzyme after lumbar spine surgery.

STUDY DESIGN: Serum concentrations of creatine phosphokinase and its isoenzyme were measured serially in 47 patients who underwent lumbar surgery. OBJECTIVE: To analyze the significance of postoperative creatine phosphokinase MM levels as indicators of muscle trauma after lumbar surgery. SUMMARY OF BACKGROUND DATA: The authors of the present study previously have reported on iatrogenic back muscle injury in an animal model and in man. However, the relationship between the change of the creatine phosphokinase MM isoenzyme level and muscle injury after surgery has not been clarified. METHODS: Peripheral venous blood samples were collected serially before surgery, just after surgery, and at 1, 3, 7, 14, and 21 days after surgery. The serum concentration of total creatine phosphokinase and its isoenzymes was measured by agarose gel electrophoresis. The serial postoperative change of the creatine phosphokinase MM isoenzyme concentration was evaluated with respect to age, gender, body weight, types and levels of surgery, and surgery time. RESULTS: Creatine phosphokinase MM activity increased after surgery and reached a maximum value 1 day after surgery, followed by recovery to the normal value 1 week after surgery. The maximum concentration of creatine phosphokinase MM isoenzyme in posterior lumbar surgery was significantly higher than that in anterior surgery (P = 0.04). It was significantly higher in men than in women (P = 0.02). Serum concentration of creatine phosphokinase MM isoenzyme showed no significant correlation to the extent of muscle exposure and surgery time. CONCLUSION: The time course of postoperative serum creatine phosphokinase MM isoenzyme activity is correlated with the histologic changes of the back muscles after surgery. The concentration of creatine phosphokinase MM isoenzyme in posterior lumbar surgery was significantly higher than that in anterior surgery. It was also significantly higher in men than in women.

Adolescent↗
PubMed1997

Intracortical facilitation and inhibition after transcranial magnetic stimulation in conscious humans.

1. Changes in excitability of the motor cortex induced by a transcranial magnetic stimulation (TMS) were examined by simultaneous recording of the evoked corticospinal volley and the compound surface electromyographic (EMG) response in the biceps brachii following paired-pulse TMS in five conscious subjects. The effects of a varying interstimulus interval (ISI) and a conditioning stimulus intensity were also investigated. 2. A submotor threshold conditioning stimulus inhibited the test responses at ISIs of 2-5 ms. A supramotor threshold conditioning stimulus inhibited the test responses at ISIs of 100-200 ms. Both of these inhibitions were prominent in late I waves. 3. There was a facilitation of the test responses at an ISI of 25 ms that was prominent in late I waves. The facilitation evoked by the supramotor threshold conditioning stimulus was more prominent than that evoked by the submotor threshold conditioning stimulus. 4. It is concluded that single TMS induced the triphasic changes of the motor cortex excitability in conscious humans that resulted in changes in EMG responses following paired TMS.

Adult↗
PubMed1997

Cloning and sequencing of cDNA encoding NG,NG-dimethylarginine dimethylaminohydrolase from rat kidney.

Three cDNA clones encoding NG,NG-dimethylarginine dimethylamino-hydrolase (EC 3.5.3.18) have been isolated from a rat kidney lambda gt11 library using a probe prepared by PCR on the basis of partially determined amino-acid sequences of the enzyme. The sequence analyses of the cDNAs established that the 3008 bp cDNA contains 855 bp open reading frame encoding 285 amino acids (M(r) 31414), 3'-flanking region (1722 bp) and 5'-flanking region (431 bp). The amino-acid sequences of all the peptides isolated from the purified enzyme were shown to be included in the deduced amino-acid sequence. Northern blotting analyses showed that the mRNA (4 kb) is ubiquitously expressed in various rat tissues.

Amidohydrolases↗
PubMed1997

Expansive lumbar laminoplasty for degenerative spinal stenosis in patients below 70 years of age.

We reviewed the clinical and radiological results of patients with lumbar degenerative spinal stenosis who underwent expansive laminoplasty with a mean follow-up term of 5.6 years. Twenty-seven patients underwent open-door-type expansive lumbar laminoplasty, which has both decompression and stabilization effects. Clinical results were assessed based on the score system devised by the Japanese Orthopaedic Association (JOA score). The number and causes of repeat surgery were also evaluated. Radiological changes, such as degenerative scoliosis and spondylolisthesis, were evaluated at the operated levels and at levels L1-L5. There was marked recovery of clinical symptoms assessed by pre- and postoperative JOA score. Nearly 80% of patients obtained good or excellent results. Only one patient (4%) required additional surgery, which involved discectomy at the caudal level of the laminoplasty. Radiographic evaluation revealed that postoperative changes of spondylolisthesis and scoliosis were slight both in the expanded area and the L1-L5 levels. Range of motion of the disc space angle in the expanded area showed a significant decrease postoperatively. However, pre- and postoperative radiological changes showed no significant correlation with JOA score changes and repeat surgery. In conclusion, lumbar fusion after posterior decompression in active patients with spinal stenosis offers satisfactory clinical results concomitantly with a relatively small risk of repeat surgery.

Age Factors↗
PubMed1997

A de novo recombination in the ABO blood group gene and evidence for the occurence of recombination products.

We have encountered a paternity case where exclusion of the putative father was only observed in the ABO blood group (mother, B; child, A1; putative father, O), among the many polymorphic markers tested, including DNA fingerprints and microsatellite markers. Cloning a part of the ABO gene, PCR-amplified from the trio's genomes, followed by sequencing the cloned fragments, showed that one allele of the child had a hybrid nature, comprising exon 6 of the B allele and exon 7 of the O1 allele. Based on the evidence that exon 7 is crucial for the sugar-nucleotide specificity of A1 and B transferases and that the O1 allele is only specified by the 261G deletion in exon 6 of the consensus sequence of the A1 allele, we concluded that the hybrid allele encodes a transferase with A1 specificity, resulting, presumably, from de novo recombination between the B and O1 alleles of the mother during meiosis. Screening of random populations demonstrated the occurrence of four other hybrid alleles. Sequencing of intron VI from the five hybrid alleles showed that the junctions of the hybrid alleles were located within intron VI, the intron VI-exon 7 boundaries, or exon 7. Recombinational events seem to be partly involved in the genesis of sequence diversities of the ABO gene.

ABO Blood-Group System↗
PubMed1997

Association of preceding angina with in-hospital life-threatening ventricular tachyarrhythmias and late potentials in patients with a first acute myocardial infarction.

We studied 140 patients with a first acute myocardial infarction to examine the effect of preceding angina as a marker of ischemic preconditioning on clinical ventricular arrhythmias and late potentials. Preceding angina was defined as the presence of ischemic chest pain within 24 hours before onset of myocardial infarction lasting no longer than 30 minutes and seen three or more times per day or at rest. Clinical features, angiographic findings, and late potentials were compared between patients with and without preceding angina. Thirty-four (24%) patients had preceding angina. Although the incidence of life-threatening ventricular tachyarrhythmias significantly differed (p = 0.0219), other clinical findings, including presence of late potentials, were not different between the two groups. Of 14 patients with life-threatening ventricular tachyarrhythmias, five events were considered as reperfusion arrhythmias. In patients who had successful reperfusion therapy, the incidence of life-threatening ventricular tachyarrhythmias had a tendency to be lower in patients with preceding angina than in those without preceding angina (p = 0.0586). Severe angina within 24 hours of onset of acute myocardial infarction is suggested to reduce occurrence of life-threatening ventricular tachyarrhythmias mainly associated with reperfusion during hospitalization.

Action Potentials↗
PubMed1997

Generation II knee bracing for severe medial compartment osteoarthritis of the knee.

OBJECTIVE: To investigate the clinical efficacy of the Generation II (G II) knee brace, a newly developed knee orthosis, on patients experiencing severe medial compartment osteoarthritis (OA) of the knee. DESIGN: Case series. SETTING: A national medical and pharmaceutical hospital in Japan. PATIENTS: Twenty primary OA subjects (excluding those with secondary OA), all older than 55 years of age and experiencing only knee joint problems, were selected according to their ability to walk more than 500 meters independent of support. These patients had arthritis in both knees and no less than one half of normal joint space remaining as revealed by roentgenogram studies. The more severely affected side was selected for bracing. INTERVENTIONS: For 12 months, each patient wore a G II knee brace on the affected knee on a daily basis, removing it only at night. To evaluate the effects of G II OA brace alone, additional use of new oral drugs or any other treatment was prohibited from 1 month before application of the G II OA brace and throughout the trial period. MAIN OUTCOME MEASURES: Clinical efficacy was evaluated using the Japan Orthopaedic Association's knee scoring system. X-ray evaluation was performed with patients standing on one leg. A dynamometer was used to evaluate isokinetic quadriceps muscle strength. The center of gravity was measured using an X-Y recording. Clinical evaluation was performed every 2 months thereafter. Final evaluation was at 12 months. RESULTS: Nineteen of the 20 patients answered that they experienced significant pain relief. Knee pain scores on walking increased from 18.0 to 21.5 and on ascending and descending stairs increased from 12.8 to 15.8. The femorotibial angle decreased in 12 of the patients, and the mean angle decreased from 185.1 degrees before application to 183.7 degrees with the brace on at the final observation period. In addition, isokinetic quadriceps muscle strength increased from an average of 36.8 Nm to 42.8 Nm for all patients. In 17 patients, quadriceps muscle strength increased, while it decreased in 2 and remained the same in 1. Finally, lateral movement of the center of gravity decreased compared with before G II application in all patients. CONCLUSION: G II bracing is a beneficial treatment for severe medial OA of the knee.

Aged↗
PubMed1997

Analysis of oil components and hydrocarbon-utilizing microorganisms during laboratory-scale bioremediation of oil-contaminated soil of Kuwait.

A huge amount of oil-contaminated soil remains unremediated in the Kuwait desert. The contaminated oil has the potentiality to cause pollution of underground water and to effect the health of people in the neighborhood. We have been studying bioremediation of Kuwait oil-contaminated soil. Chemical analyses of biodegraded compounds and isolation of petroleum hydrocarbon-decomposing microorganisms were carried out. From the chemical analyses, it was revealed that the decomposed compounds were mainly saturated fractions from alumina column chromatography and that the aromatic fractions were not decomposed well. Isolation of bacteria was carried out for eight kinds of hydrocarbons which are components of crude petroleum (n-hexadecane, 2,6,10,14-tetramethylpentadecane, 1,4-diisopropylbenzene, naphthalene, 1-methylnaphthalene, phenanthrene, anthracene, and perylene). Many of the n-hexadecane- and 2,6,10,14-tetramethylpentadecane-decomposing bacteria were isolated, but aromatic compound-decomposing bacteria were not enriched. It was concluded that the slow decomposition of aromatic compounds was due to the low population of aromatic compound-decomposing bacteria in the Kuwait desert soil.

Bacteria↗