Endothelium-derived contracting factors

In the past decade, the importance of endothelium in modulating vascular tone has become apparent. Endothelium can produce different vasodilators, such as prostacyclin, endothelium-derived relaxing factor (most likely nitric oxide), and endothelium-derived hyperpolarizing factor. Endothelium can also produce endothelium-derived contracting factors (EDCF) which can induce constriction of the underlying vascular smooth muscle. Constriction may be mediated by a variety of products released by the endothelium. Thus, by responding to various stimuli and releasing either relaxing or contracting factors, the endothelium can set and modulate vascular tone.

Oxidized low-density lipoprotein enhances monocyte-endothelial cell binding against shear-stress-induced detachment

Oxidatively modified low-density lipoprotein may be involved in the adherence of blood monocytes to arterial endothelium in the early atherosclerotic lesion. The present study employed static assays and flow-chamber technique to investigate the adhesive interactions between isolated human blood monocytes and cultured human umbilical vein endothelial cell (EC) monolayer pretreated with Cu(2+)-oxidized human plasma LDL (Ox-LDL) and native LDL (N-LDL). The cell-cell binding force was estimated by the intensity of wall shear stress needed to detach monocytes from an EC monolayer. The number of monocytes attached to EC monolayer was quantitated by microscopic observation, measurement of myeloperoxidase (MPO) activity in monocyte and cellular uptake of Rose Bengal stain. The results show that the proadhesive activity of EC surface for monocytes was strongly induced by Ox-LDL and weakly modulated by N-LDL. Pretreatment of an EC monolayer with Ox-LDL (25 micrograms/ml) for 6 h induced a 2.2-fold increase in the number and an 8-fold increase in the force of monocyte binding to EC monolayer as compared to untreated control. A significant number of monocytes (4.4-times control) were able to maintain their adhesion to Ox-LDL-pretreated EC monolayer under high shear stress (30 dyn/cm2). The cell surface expression of intercellular adhesion molecule 1 (ICAM-1), but not vascular cell adhesion molecule 1 (VCAM-1), in umbilical vein EC was increased by 2.6-fold after treatment of EC with Ox-LDL (50 micrograms/ml) for 6 h compared with non-treated control. On prolonged (> 12 h) incubation, Ox-LDL (> 100 micrograms/ml) was found to have cytotoxic effect on EC as reflected by the loss of EC integrity and detachment at low shear stress. It indicates that a sublethal dose of oxidized LDL may alter vascular endothelium physiology, up-regulate expression of ICAM-1 in EC, enhance monocytes binding against shear-stress-induced detachment, and thus may contribute to atherogenesis.

kil-kor regulon of promiscuous plasmid RK2: structure, products, and regulation of two operons that constitute the kilE locus

The kil-kor regulon of IncP plasmid RK2 is a complex regulatory network that includes genes for replication and conjugal transfer, as well as for several potentially host-lethal proteins encoded by the kilA, kilB, and kilC loci. While kilB is known to be involved in conjugal transfer, the functions of kilA and kilC are unknown. The coregulation of kilA and kilC with replication and transfer genes indicates a possible role in the maintenance or broad host range of RK2. In this work, we found that a fourth kil locus, designated kilE, is located in the kb 2.4 to 4.5 region of RK2 and is regulated as part of the kil-kor regulon. The cloned kilE locus cannot be maintained in Escherichia coli host cells, unless korA or korC is also present in trans to control its expression. The nucleotide sequence of the kilE region revealed two potential multicistronic operons. The kleA operon consists of two genes, kleA and kleB, predicted to encode polypeptide products with molecular masses of 8.7 and 7.6 kDa, respectively. The kleC operon contains four genes, kleC, kleD, kleE, and kleF, with predicted products of 9.2, 8.0, 12.2, and 11.3 kDa, respectively. To identify the polypeptide products, each gene was cloned downstream of the phage T7 phi 10 promoter and expressed in vivo in the presence of T7 RNA polymerase. A polypeptide product of the expected size was observed for all six kle genes. In addition, kleF expressed a second polypeptide of 6 kDa that most likely results from the use of a predicted internal translational start site. The kleA and kleC genes are each preceded by sequences resembling strong sigma 70 promoters. Primer extension analysis revealed that the putative kleA and kleC promoters are functional in E. coli and that transcription is initiated at the expected nucleotides. The abundance of transcripts initiated in vivo from both the kleA and kleC promoters was reduced in cells containing korA or korC. When korA and korC were present together, they appeared to act synergistically in reducing the level of transcripts from both promoters. The kleA and kleC promoter regions are highly homologous and contain two palindromic sequences (A and C) that are the predicted targets for KorA and KorC proteins. DNA binding studies showed that protein extracts from korA-containing E. coli cells specifically retarded the electrophoretic mobility of DNA fragments containing palindrome A. Extracts from korC-containing cells altered the mobility of DNA fragments containing palindrome C. These results show that KorA and KorC both act as repressors of the kleAand kleC promoters. In the absence of korA and korC, expression of the cloned kleA operon was lethal to E.coli cells, whereas the cloned kleC operon gave rise to slowly growing, unhealthy colonies. Both phenotypes depended on at least one structural gene in each operon, suggesting that the operons encode genes whose products interact with critical host functions required for normal growth and viability. Thus, the kilA, kilC, and kilE loci of RK2 constitute a cluster of at least 10 genes that are coregulated with the plasmid replication initiator and the conjugal transfer system. Their potential toxicity to the host cell indicates that RK2 is able to establish a variety of intimate plasmid-host interactions that may be important to its survival in nature.

Thoracic actinomycosis

Actinomycotic infection is uncommon and primary actinomycosis of the lung and chest wall has been less frequently reported. This disease may present as chronic debilitating illness with radiographic manifestation simulating lung tumor, pulmonary infiltrating lesion, or chronic suppuration. From 1984 to 1990, we experienced 17 cases of thoracic actinomycosis. There were nine patients who presented with a clinical picture of a suppurative lesions and the remaining eight were suspected of having primary lung tumor initially. In no case was an accurate diagnosis made at the time of hospital admission. Final diagnosis was based on aspiration (n = 3), anaerobic sputum culture (n = 1), bronchoscopic biopsy specimens (n = 4), and histologic examination of the resected tissue in the remaining 9 patients who received surgical excision. Among the 17 patients, 8 were treated medically and the other 9 received surgical intervention followed by antibiotic treatment. Regarding the surgically treated patients, suspected malignancy is the most common indication for operation (seven of nine). However, both medically and surgically treated patients achieved good clinical results, and the postoperative courses were uneventful. We would like to remind physicians of this unusual entity and review our own experience with particular emphasis on the clinical diagnosis and management of this unique disease.

Breast biopsy for nonpalpable lesions: a worthwhile endeavor?

The purpose of this study was to determine our yield of carcinoma in patients with a nonpalpable mammographic abnormality and to identify which mammographic criteria will most likely yield a positive biopsy. We conducted a review of all patients with nonpalpable mammographic abnormality who underwent needle-localized breast biopsy at our institution from 1988 to 1991. Charts of 295 patients who underwent 332 needle-localized breast biopsy were reviewed for age, family history, cancer history, mammographic findings, operative time, volume of excised breast tissue, and histology. Mammographic abnormalities were categorized as suspicious (clustered) microcalcification, stellate mass, ill-defined mass, well-circumscribed mass, developing density, or asymmetric density. The overall yield of cancer positive biopsies was 48 of 332 (14.5%). The frequency of diagnosed cancers was DCIS (8), LCIS (1), Stage I (31) and Stage II (8). The frequency that each single mammographic criteria resulted in a cancer diagnosis was: suspicious calcification (12%), stellate mass (22%), ill-defined mass (14%), well-circumscribed mass (11%), developing density (9%) and asymmetric density (0%). However, patients with both a stellate mass and microcalcifications formed the highest risk subgroup, with cancer detected 66 per cent of the time (P = 0.03).

Thromboxane A2: an endothelium-derived vasoconstrictor in human internal mammary arteries

The internal mammary artery (IMA) has become the conduct of choice for coronary artery bypass grafting. However, the IMA graft can exhibit vasoconstriction during the perioperative period. Experiments were designed to determine the role of cyclooxygenase products in human IMA during hypoxia. Rings of IMA, with and without endothelium, were suspended in organ baths containing physiologic salt solution. Rings were contracted with norepinephrine and then exposed to hypoxia for 15 minutes. In segments with endothelium, hypoxia induced a transient relaxation followed by contraction. This contraction was associated with a significantly increased production of thromboxane B2, the stable metabolite of thromboxane A2 (n = 10; from 120.7 +/- 3.5 pg/mg wet tissue before hypoxia to 175.8 +/- 5.2 pg/mg during hypoxia; p < 0.05). This hypoxic contraction could be attenuated by indomethacin. However, thromboxane B2 could not be detected in samples from organ baths containing IMA segments without endothelium before or during hypoxia. This study demonstrated that endothelium of human IMA grafts releases thromboxane A2 basally and that production is augmented by hypoxia, which acts to constrict the underlying vascular smooth muscle, increase vascular tone, and promote ischemic events such as vasospasm and thrombosis, particularly in hypoxemic patients.

Gastro-pleural fistula related with penetrating stab injuries of the chest and abdomen: laparotomy or thoracotomy

A 30-year-old male presented with left side empyema due to gastro-pleural fistula following repair of penetrating stab injuries of left lower chest and abdomen. Exploratory thoracotomy was done due to persistent moderate amount of purulent discharge. However, fistula tract was not detected through this approach. The small fistula tract was repaired finally through laparotomy. We recommended the abdominal approach if the disease is not combined with diaphragmatic hernia. Transabdominal approach showed superiority in this rare entity.

Acute renal failure after open heart surgery: clinical experience with continuous arteriovenous hemodialysis

Continuous arteriovenous hemodialysis (CAVHD) was employed in five patients who suffered from acute renal failure (ARF) after open heart surgery during the period from July 1991 to February 1992. All patients had a urine output of less than 400 mL/24h and clinical evidence of fluid overload. Most of the patients needed respiratory support for respiratory insufficiency and required vasopressor infusions. They could not tolerate conventional hemodialysis due to severe hemodynamic instability, and the concurrent thoracic surgery precluded the application of peritoneal dialysis. All patients tolerated the CAVHD well, despite persistent hypotension. The mean age of the five patients was 53.6 +/- 15.3 years. The duration of CAVHD treatment ranged from 1.5 to 22 days. Whole blood clearances for urea, creatinine and phosphate were 13.27 +/- 1.86 mL/min, 13.05 +/- 3.12 mL/min, and 13.99 +/- 2.61 mL/min, respectively. According to the clinical condition, ultrafiltration averaged 100-200 mL/h; up to 1 L/h could be obtained without difficulty. In these situations, large concurrent amounts of vasopressors and nutritional fluids could be easily prescribed without fear of fluid overload. The introduction of CAVHD allowed a more stabilized environment for gradual recovery of the temporarily compromised ventricular function after open heart surgery. Later, the hemodynamic status was stabilized without or with only minimal infusions of vasopressors in all five patients. Renal function recovered in four patients and one was shifted to conventional hemodialysis. All five patients survived under CAVHD treatment. There were no significant complications related to the application of CAVHD.(ABSTRACT TRUNCATED AT 250 WORDS)

Recursive partitioning analysis of prognostic factors in three Radiation Therapy Oncology Group malignant glioma trials

BACKGROUND

Despite notable technical advances in therapy for malignant gliomas during the past decade, improved patient survival has not been clearly documented, suggesting that pretreatment prognostic factors influence outcome more than minor modifications in therapy. Age, performance status, and tumor histopathology have been identified as the pretreatment variables most predictive of survival outcome. However, an analysis of the association of survival with both pretreatment characteristics and treatment-related variables is necessary to assure reliable evaluation of new approaches for treatment of malignant glioma.

PURPOSE

This study of malignant glioma patients used a non-parametric statistical technique to examine the associations of both pretreatment patient and tumor characteristics and treatment-related variables with survival duration. This technique was used to identify subgroups with survival rates sufficiently different to create improvements in the design and stratification of clinical trials.

METHODS

We used a recursive partitioning technique to analyze survival in 1578 patients entered in three Radiation Therapy Oncology Group malignant glioma trials from 1974 to 1989 that used several radiation therapy (RT) regimens with and without chemotherapy or a radiation sensitizer. This approach creates a regression tree according to prognostic variables that classifies patients into homogeneous subsets by survival. Twenty-six pretreatment characteristics and six treatment-related variables were analyzed.

RESULTS

The years). Patients younger than 50 years old were categorized by histology (astrocytomas with anaplastic or atypical foci [AAF] versus glioblastoma multiforme [GBM]) and subsequently by normal or abnormal mental status for AAF patients and by performance status for those with GBM. For patients aged 50 years or older, performance status was the most important variable, with normal or abnormal mental status creating the only significant split in the poorer performance status group. Treatment-related variables produced a subgroup showing significant differences only for better performance status GBM patients over age 50 (by extent of surgery and RT dose). Median survival times were 4.7-58.6 months for the 12 subgroups resulting from this analysis, which ranged in size from 32 to 256 patients.

CONCLUSIONS

This approach permits examination of the interaction between prognostic variables not possible with other forms of multivariate analysis.

IMPLICATIONS

The recursive partitioning technique can be employed to refine the stratification and design of malignant glioma trials.

Primary chylopericardium: report of a case

A 14-year-old girl was admitted due to exertional dyspnea of one month's duration. A grade 3/6 holosystolic murmur with distant heart sounds was heard at the left sternal border. Chest roentgenograms and echocardiograms showed a large amount of pericardial and left pleural effusion and a small perimembranous ventricular septal defect. Subxyphoid pericardial drainage and left pleural intubation were performed. The fluid from both sites was defined as chyle by the milky white appearance, presence of microscopic fat droplets and the lymphocyte predominance in the white cell count. Lymphangiograms and a chest computed tomographic scan demonstrated thoracic duct obstruction and leakage of contrast to pericardial and pleural spaces. The patient was treated with a medium chain triglyceride diet. Unfortunately, massive reaccumulation of the effusion was later noted. Therefore, a median sternotomy with ligation of the thoracic duct, creation of a posterior pericardio-pleural window and implantation of a left pleuro-peritoneal shunt with a Denver peritoneo-venous shunt were performed. Follow-up for one year with two-dimensional echocardiograms showed no more accumulation of the pericardial effusion.

Modified Fontan procedure for complex congenital heart disease

The Fontan procedure is frequently used for correction of complex congenital heart disease, but the postoperative morbidity and mortality rates are still high. The results in 35 consecutive patients who underwent the Fontan procedure from January 1980 to June 1991 are reviewed. The patients comprised 26 boys and nine girls aged from 1.7 to 14.8 (mean 6.8) years. The underlying diseases were univentricular heart (19 patients), tricuspid atresia (eight), complete atrioventricular canal (three patients, two of whom had straddling atrioventricular valve) and other conditions (five). Valved conduits were implanted in four patients and non-valved in 15. Direct right atrium-pulmonary artery anastomosis was performed in 16 patients. The overall hospital mortality rate was 23% (eight patients); in the final year of the review it was 11%. Follow-up of the survivors ranged from 1 to 120 (mean 25) months. All except two patients attained New York Heart Association functional class I or II. Three patients underwent reoperation for atrioventricular valve regurgitation and conduit stenosis with good results. It is concluded that the Fontan procedure is a good palliative operation for complex congenital heart disease.

Structure, function, and regulation of the kilB locus of promiscuous plasmid RK2

The kil-kor regulon of the self-transmissible, broad-host-range plasmid RK2 is a unique network with eight coregulated operons. Among the genes encoded by the kil-kor regulon are trfA, which encodes the replication initiator, and several kil loci (kilA, kilB, kilC, and kilE), each of which is lethal to the host cell in the absence of appropriate negative regulatory elements encoded by the korA, korB, korC, and korE determinants. We have proposed that the functions of the kil loci are related to RK2 maintenance or host range. Here, we report the nucleotide sequence of a 2.44-kb region that includes the lethal kilB determinant. We identified the first three genes of the kilB operon (designated klbA, klbB, and klbC), and we determined by deletion analysis that the host-lethal phenotype requires klbB. The predicted amino acid sequence of the 34,995-Da klbA product reveals a potential ATP-binding fold. The klbB product is predicted to be a membrane protein with a molecular mass of 15,012 Da with homology to the RK2 KlaC membrane protein encoded by the kilA operon. The amino acid sequence of the 12,085-Da klbC product contains a perfect match to the leucine zipper motif common to eukaryotic regulatory proteins. Primer extension analysis revealed unambiguously that transcription of the kilB operon begins 46 nucleotides upstream of klbA. No transcription was initiated from the sequence previously presumed by other investigators to be the kilB promoter. The abundance of kilB transcripts is reduced in the presence of KorB, consistent with the prediction that KorB acts at the level of transcription. A degenerate KorB-binding site that contains a perfect half-palindrome overlaps the kilB promoter, but this site is insufficient for regulation by KorB. The region containing a KorB-binding site located 183 bp upstream of the transcriptional start is required for regulation by KorB, indicating that KorB acts at a distance to regulate transcription of kilB. Our studies with the mutant plasmid pRP101, a transfer-defective derivative of the RK2-like plasmid RP4, demonstrated that the kilB operon includes the conjugal transfer and surface exclusion genes of the Tra2 region. Nucleotide sequence analysis revealed that the transposon Tn7 insertion in pRP101 is located in the klbC gene, and complementation analysis showed that this mutation has a strong polar effect on the expression of genes for conjugal transfer and surface exclusion located several kilobases downstream. A klbA mutant was constructed and found to be both transfer defective and complementable, thus, demonstrating a requirement was constructed and found to be both transfer defective and complementable, thus demonstrating a requirement for klbA product in plasmid transmissibility. These results have demonstrated a role for the kilB operon in conjugal transfer. The kil-kor regulon of RK2 is the only known example of plasmid-mediated coregulation of replication and transfer.

Melittin potentiates guanylate cyclase activation stimulated by atrial natriuretic factor and ATP

The biologically relevant receptor for atrial natriuretic factor (ANF) has been shown to be membrane-bound guanylate cyclase. While guanylate cyclase is known to be activated by ANF and ATP, the molecular mechanism of the enzyme activation remains unclear. We now show that melittin, the main peptide toxin of bee venom, activates membrane-bound guanylate cyclase and potentiates ANF- and ATP-stimulated guanylate cyclase activity in rat lung membranes. Melittin stimulated basal guanylate cyclase activity by increasing the Vmax without significantly affecting the Km of the substrate, GTP. However, melittin enhances ANF- and ATP-stimulated enzyme activity by altering both the Vmax and the EC50 of ANF and ATP. Although melittin activates guanylate cyclase in crude membranes, it has little effect on the activity of the purified enzyme. The effect of melittin on guanylate cyclase activation in rat lung membranes is attenuated by the Ca2+ chelator, EGTA. These results suggest that the effects of melittin on guanylate cyclase activation may require the participation of accessory proteins or nonprotein factors. Therefore, melittin would be a valuable tool for exploring the molecular mechanisms of ANF-mediated guanylate cyclase activation.

Endothelium-derived relaxing factors

The endothelium modulates vascular tone by liberating both dilator [endothelium-derived relaxing factors; EDRFs]and constrictor substances [endothelium-derived contracting factors; EDCFs]. This review focused on endothelium-derived relaxing factor, its discovery, characteristics, synthesis and interaction with vascular smooth muscle. The major endothelium-derived relaxing factor is nitric oxide formed from L-arginine, which activates guanylate cyclase in the smooth muscle, leading to accumulation of cyclic-GMP. Endothelial cells can also release endothelium-derived hyperpolarizing factor EDHF which also cause endothelium-dependent relaxation.

Arterial switch operation in a neonate with simple transposition of great arteries

Transposition of the great arteries (TGA) is characterized by severe and life-threatening hypoxemia during a newborn period. Without treatment, most of the patients die during early infancy. We reported a 20-day-old male newborn who was referred to our hospital due to severe cyanosis and respiratory distress. Echocardiograms revealed D-TGA with an intact ventricular septum. There was no pulmonary stenosis or other major cardiac anomalies. The cardiac catheterization and angiographic findings which were performed 4 days later were consistent with the diagnosis of echocardiography. The systolic left and right ventricular pressures were 65 and 69 mmHg respectively. Arterial switch operation was performed at the age of 28 days. Postoperative course was uneventful. The cardiac recatheterization and angiographic study performed 6 months after operation, and the latest non-invasive examination including chest X-ray, electrocardiogram and echocardiographic assessment revealed good ventricular performance and normal semilunar valve function. There was no obstruction at the anastomotic site. The patient has been doing well with regular follow-up at our clinic for 2 years and 6 months without medication.

CT characteristics of patients with brain metastases treated in RTOG study 79-16

The search continues for a favorable subgroup of patients with brain metastases in whom testing of new modalities might show a benefit in overall survival. Complete pre- and post-treatment CT evaluation of the brain was performed in 779 of the 859 patients entered into RTOG protocol 7916, a phase III study of the role of misonidazole combined with radiation therapy in the treatment of brain metastases. Pretreatment scan findings of mass effect, midline shift, massive edema, central necrosis, location of sentinel lesion, and number of lesions were correlated with length of survival for all patients as well as for each treatment group. The only characteristics that showed a statistically significant difference in survival in the overall group were the presence of < or = 3 lesions and the presence of a midline shift. The actual benefit in overall survival, however, was found to be only 3 weeks. The volume of the largest lesion prior to treatment did not correlate well with survival, nor did location of lesions. The time to response, number of responders and absolute decrease in number of lesions were similar for the four treatment arms. Patients who responded to cranial treatment had a significantly prolonged survival over those who did not respond. No CT characteristic evaluated in this study showed value as a clinically relevant prognosticator for patients with brain metastases for the overall group. Patients who fulfilled three of the four favorable clinical characteristics previously described by Diener-West (age < or = 60, KPS > or = 70, primary lesion absent or controlled and brain as sole site of metastasis), were analyzed separately. Those with < or = three lesions had a statistically significantly prolonged survival over those with four or more lesions.

Pulmonary artery perforation after Kirschner wire migration: case report and review of the literature

Utilization of Kirschner wires for bone and joint fixation is potentially complicated by migration of the wire from the fixation site over time. However, a review of the literature disclosed few reports of this complication. We describe such a case in order to emphasize the potential danger of the migration of such metallic devices used near thoracic cavity.

Prediction of fetal macrosomia by single ultrasonic fetal biometry

A total of 1,056 fetuses underwent single ultrasonographic measurement of fetal biparietal diameter (BPD), abdominal circumference (AC), femur length (FL), and estimated body weight within five days of delivery. The accuracy of these parameters and estimated body weight equations in the prediction of macrosomia (birth weight > or = 4,000 g) was evaluated. With the use of receiver operator characteristic curves, the optimal cutoff value for each parameter with the best sensitivity, specificity and accuracy was selected. BPDs > or = 9.4 cm had the best sensitivity (68.8%), specificity (74.3%), and accuracy (74.1%). ACs > or = 35 cm had the best sensitivity (81.3%), specificity (81.5%), and accuracy (81.5%). FLs > or = 7.0 cm had the best sensitivity (68.8%), specificity (74.5%), and accuracy (74.3%). The estimated body weight equations did not increase the prediction values whether or not FL was included. Both had the same prediction values at > or = 3,700 g, ie, sensitivity (71.9% vs 71.9%), specificity (92.1% vs 93.8%), and accuracy (91.5% vs 93.2%). The results showed AC to be the best single parameter for predicting macrosomia. Combinations of these parameters were better than a single parameter in the prediction of macrosomia.

Growth of human melanocytes from suction blister of localized vitiligo patient and from foreskins of newborns and adults by modified culture medium

We report on the culturing of melanocytes from suction blisters from the uninvolved skin of localized (focal and segmental) vitiligo patients and from the foreskins of newborns and adults, over a long period of time using a modified culture medium composed of F-12 medium supplemented with insulin (5 mg/mL), cholera toxin (40 ng/mL), transferrin (5 mg/mL), hydrocortisone (1 mM), epithelial growth factor (20 ng/mL), endothelial cell growth supplement (ECGS) (15 mg/mL), retinol (1 x 10(-7) M), 12-o-tetradecanoyl-phorbol-13 acetates (TPA) (85 nM), and 1% fetal calf serum (FCS). This method may be used in in vitro studies on normal human melanocytes and for study of the difference between melanocytes of normal individuals and of those with vitiligo. The ability to culture melanocytes from localized vitiligo, and the inability to grow those of generalized vitiligo with this system reconfirms the difference in the pathogenesis of various types of vitiligo. Thus, culturing may be used for differentiating localized vitiligo from generalized vitiligo and may be used to guide the mode of treatment when vitiligo has just started to develop and only a few depigmented patches have appeared. The results of studies on seeding density effect and serial Dopa reaction on the melanocytes of normal individuals reveal that the use of tyrosinase activity as the assessment parameter requires the use of melanocytes cultured for less than five months at a seeding density of less than 4 x 10(4) cells/cm2. Enlarged and heavily pigmented cells, senescent cells, were observed after very long-term culture (one year and four months).(ABSTRACT TRUNCATED AT 250 WORDS)

[Congenital esophageal stenosis with submucosal fibrosis: report of one case]

Esophageal stenosis due to an intrinsic congenital factor is uncommon in infancy. We report a case of a male newborn infant, who was well at birth and presented with foamy sputum from the third day of life and vomiting at 18 days of age. Esophagogram revealed a narrowed segment, about 1 cm in length, at the level of the seventh and eighth cervical vertebral bodies, with proximal dilatation. There was no sign of gastroesophageal reflux. Operative findings: There was no external compression, foreign body or fistula, but a 1 cm length of esophageal stenosis was found. The stenosed segment was hard on palpation. Segmental resection of the stenosed region, with direct anastomosis of the esophagus was performed. Pathological examination of the narrowed segment revealed fibrosis of the submucosa without any tracheobronchial remnent components.

Surgical management of thrombotic disc valve

Thrombotic obstruction, a rare but often fatal complication of cardiac valve prostheses, appears to occur more frequently in tilting-disc valves than in other valve designs. Its diagnosis and surgical treatment remain a challenge. Ten consecutive patients who had thrombosis of a tilting-disc valve prosthesis were treated in Chang Gung Memorial Hospital from November 1982 to August 1990. Preoperative clinical features, including exertional dyspnea, new murmur, and absence of a metallic click from the prosthetic valve, occurred in all of the patients. Symptoms were present for 1 week or more before reoperation in 70% of the patients; nevertheless, many patients were referred only after acute exacerbation of heart failure and development of pulmonary edema. Echocardiography confirmed prosthetic valve malfunction in 90% of the patients. One unconfirmed case was later documented by cardiac catheterization. Anticoagulant therapy was in the therapeutic range for only half of the patients at the time of admission. Prompt reoperation was performed for thrombectomy (8 patients, all survived) or valve replacement (2 patients, one death). Long-term outcome was satisfactory in all survivors with a mean follow-up of 31.6 months. These findings emphasize the importance of considering the diagnosis of thrombosis in patients with mechanical heart valve prostheses who are first seen with nonspecific symptoms and minor changes of their physical findings. The diagnosis could be easily made by echocardiography. Thrombectomy is an easy, fast, and safe procedure, especially for these critically ill patients.

A knowledge-based computer-aided design and manufacturing system for total hip replacement

A knowledge-based computer-aided design and manufacturing system (CAD-CAM) has been developed for total hip replacement. Knowledge-based refers to the fact that the design process is a computer program that has been provided with preprogrammed design rules. Compared with conventional CAD-CAM systems, the knowledge-based system is automated, requires less designer intervention, and increases the accuracy of the design process. The capabilities of the system make it ideal for the design of standard and custom total hip replacement. A full-fill, press-fit custom total hip replacement has been designed using the knowledge-based system. The early clinical results of a series of 37 replacements in 31 patients is described in this paper.