Human placenta-derived cells have mesenchymal stem/progenitor cell potential

Mesenchymal stem/progenitor cells (MSCs) are widely distributed in a variety of tissues in the adult human body (e.g., bone marrow [BM], kidney, lung, and liver). These cells are also present in the fetal environment (e.g., blood, liver, BM, and kidney). However, MSCs are a rare population in these tissues. Here we tried to identify cells with MSC-like potency in human placenta. We isolated adherent cells from trypsin-digested term placentas and established two clones by limiting dilution. We examined these cells for morphology, surface markers, gene expression patterns, and differentiation potential and found that they expressed several stem cell markers, hematopoietic/ endothelial cell-related genes, and organ-specific genes, as determined by reverse transcription-polymerase chain reaction and fluorescence-activated cell sorter analysis. They also showed osteogenic and adipogenic differentiation potentials under appropriate conditions. We suggest that placenta-derived cells have multilineage differentiation potential similar to MSCs in terms of morphology, cell-surface antigen expression, and gene expression patterns. The placenta may prove to be a useful source of MSCs.

Erythropoiesis from acetyl LDL incorporating endothelial cells at the preliver stage

Erythropoiesis is characterized by 2 waves of production during mouse embryogenesis: a primitive one originating from the yolk sac (YS) and a definitive one produced from both the YS and the embryo proper. How the latter wave is generated remains unclear. To investigate our hypothesis that endothelial cells (ECs) could generate erythroid cells, we designed a method to label ECs at 10 days after coitus. This labeling method associates 2 techniques: an intracardiac inoculation that allows molecules to be delivered into the bloodstream followed by a whole-embryo culture period. DiI-conjugated acetylated low-density lipoproteins (Ac-LDL-DiI) were used to specifically tag ECs from the inside. One hour after inoculation, DiI staining was found along the entire endothelial tree. Fluorescence-activated cell sorter (FACS) analysis revealed that DiI+ cells were CD31+, CD34+, and CD45-, an antigen makeup characteristic of the endothelial lineage. Twelve hours after inoculation, 43% of DiI+ circulating cells belonged to the erythroid lineage. These cells expressed Ter119 and displayed an adult globin chain arrangement; thus they belonged to the definitive lineage as confirmed in erythroid colony formation. The remaining cells likely represent committed white blood cells or multipotent progenitors, as revealed by a mixed-colony formation. Beyond the 29-somite stage, the proportion of DiI+ erythroid cells gradually decreased. These results demonstrate the generation of hematopoietic cells from an endothelial intermediate, using in vivo tracing. We provide evidence for a release of these cells into the circulation and hypothesize that these cells are able to colonize the fetal liver and generate definitive erythrocytes in vivo.

Mechanism of transient mental nerve paraesthesia in sagittal split mandibular ramus osteotomy

We investigated the mechanism involved in paraesthesia associated with sagittal split mandibular ramus osteotomy by three-dimensional computed tomography (3-D CT). Ten female patients underwent this procedure between 1988 and 1991. The inferior alveolar neuro-vascular bundles remained intact during the sagittal osteotomy in all cases. We examined the changes in the shape of the foramen mandibulae over a period of 6 months during which the transient mental nerve paraesthesia was recovered, and studied the distance from the foramen mandibulae to the spina mentalis (F-S distance) as measured on 3-D film. The postoperative 3-D CT scan showed bone resorption in front of the foramen mandibulae, and the F-S distance was shortened by an average of 2.94 mm. These findings suggest that possible causes of the paraesthesia is due to compression of the nerve trunk resulting from posterior movement of the mandibular ramus.

Methylation status of the p15 and p16 genes in paediatric myelodysplastic syndrome and juvenile myelomonocytic leukaemia

Aberrant DNA methylation is frequently observed in adults with myelodysplastic syndrome (MDS), and is recognized as a critical event in the disease's pathogenesis and progression. This is the first report to investigate the methylation status of p15 and p16, cell cycle regulatory genes, in children with MDS (n = 9) and juvenile myelomonocytic leukaemia (JMML; n = 18) by using a methylation-specific polymerase chain reaction. The frequency of p15 hypermethylation in paediatric MDS was 78% (7/9), which was comparable to that in adult MDS. In contrast, p15 hypermethylation in JMML was a rare event (17%; 3/18). In JMML, clinical and laboratory characteristics including PTPN11 mutations and aberrant colony formation were not different between the three patients with hypermethylated p15 and the others. Aberrant methylation of p16 was not detected in children with either MDS or JMML. Since p15 and p16 genes were unmethylated in two children with JMML, in whom the disease had progressed with an increased number of blasts, a condition referred to as blastic crisis, we infer that the aberrant methylation of these genes is not responsible for the progression of JMML. The results suggest that demethylating agents may be effective in most children with MDS and a few patients with JMML.

Frequency of anesthetic cardiac arrest and death in the operating room at a single general hospital over a 30-year period

STUDY OBJECTIVES

To determine the anesthetic cardiac arrest (CA) and death rates in the operating room (OR) and to determine whether anesthetic CA and death are preventable.

DESIGN

Prospective study.

SETTING

OR suite of a general teaching hospital.

PATIENTS

85,708 patients undergoing surgery over a 30-year period.

MEASUREMENTS AND MAIN RESULTS

Anesthetic CAs and deaths were identified, their causes and preventability were determined on the day of occurrence, and they were recorded over the years 1962 to 1992. Four anesthetic CAs (0.5 arrest per 10,000 anesthetics) and 1 death (0.1 death per 10,000 anesthetics) occurred during the 30-year study period.

CONCLUSIONS

The results of 30 years' experience do not support the hypothesis that all anesthetic CAs and deaths are preventable. However, careful clinical management can reduce their frequency to a level lower than those reported in the referenced literature.

Necrotizing buccal and cervical fasciitis

A bite wound led to necrotizing fasciitis in the temporal space, the lateral pharyngeal space and the carotid sheath, indicative of a Streptococcus and Bacteroides infection, and was successfully treated with repeated incisions, radical debridement and antibiotic therapy.

Melanosomes of pigmented basal cell epithelioma

Electron microscopic examination of a pigmented basal cell epithelioma of scrotal skin revealed many tumor cells and melanocytes which were laden with large packages of melanosomes. In tumor cells these packages were delimited by either single- or double-limiting membranes or were not membrane bound. The matrix of these large complexes was less electron dense and homogeneous than normal, containing electrontranslucent droplets besides melanosomes. No remnants of intracellular organelles such as nucleus, mitochondria or ribosomes could be found. The basal cell epithelioma cells in this case appear to have differentiated toward fetal basal cells and have developed the ability to phagocytize large packages of melanosomes.

Xeroderma pigmentosum variant associated with multiple skin cancers and a lung cancer

A 65-year-old Japanese man with a xeroderma pigmentosum (XP) variant, XP127TO, is described. The XP127TO skin fibroblasts exhibited the typical XP variant characteristics of a 1.5-fold higher sensitivity than normal cells to the lethal effect of 254 nm ultraviolet (UV) light and the normal level of unscheduled DNA synthesis induced by 254 nm UV. Caffeine dose-dependently increased the cytotoxic effect of 254 nm UV on XP127TO cells. Clinically, the patient developed not only 3 cutaneous squamous cell carcinomas on sun-exposed areas but also an adenocarcinoma of the upper lobe of the right lung. A review of the 14 documented Japanese XP patients with nonskin malignancies indicates that the incidence of nonskin malignancy in XP patients is much lower than that of skin cancer in XP but higher than that in the general population.

A report of 14,195 applications of anesthetics to oral and maxillofacial surgery at one teaching dental hospital (1971-2000) centering around airway problems

STUDY OBJECTIVES

To examine the validity of our methods of anesthesia, i.e., awake intubation and assisted manual ventilation, in coping with the anesthetic problems particular to oral and maxillofacial surgery (OMF surgery).

DESIGN

Prospective study.

SETTING

Operating room and ward of a dental teaching hospital.

PATIENTS

14,195 patients undergoing OMF surgery during the period from January 1971 to March 2000.

MEASUREMENTS AND MAIN RESULTS

The kinds of anesthetic difficulties centering around airway problems and their frequency in OMF surgery were determined. In 2,401 patients (16.9%), awake intubation was employed because of definite or possible airway problems. No untoward effects due to awake intubation were noted. Volatile anesthetics were used with nitrous oxide (N2O) in 13,959 patients (98.3%), and their spontaneous respiration were assisted manually for the purpose of early detection of airway troubles such as accidental extubation, dislocation, kinking, and/or damage to the endotracheal tubes. Few accidents or complications were noted in relation to airway issues, and neither cardiac arrest nor death was experienced in these 14,195 patients.

CONCLUSIONS

Based on a sufficient number of anesthetic applications, awake intubation and assisted manual ventilation were proved to be useful in coping with the anesthetic difficulties particular to OMF surgery.

Histological evaluation of allograft bone after acetabular revision arthroplasty: report of two cases

We recently had the opportunity to take histological sections from two patients who underwent acetabular reconstruction in which allograft and ME Müller acetabular roof reinforcement rings were used. In one patient (case 1), histological sections of the chipped allograft were taken on two separate occasions from the same area, at 7 months, and at 3 years and 11 months after the bone graft. The histology of the chipped allograft showed necrosis at 7 months, but almost normal morphology of trabecular bone formation at 3 years and 11 months after the bone graft. In the other patient (case 2) histological sections of the block allograft and chipped allograft were taken at 1 year and 8 months after the bone graft. The block allograft showed only a small amount of admixture of newly formed bone with the necrotic bone, while the chipped allograft showed a large amount of newly formed bone, with only a small amount of necrotic bone remaining. Therefore, we principally use chipped allograft for acetabular reconstruction, in order to achieve early and complete graft incorporation. If a block allograft is used in a weight-bearing area, it should be protected from excessive load by using an acetabular reinforcement device.

Differential vasodilator effect of nitroglycerin on systemic capacitance and resistance vessels in anesthetized dogs, and the mechanism of its action--a study by measuring mean circulatory pressure and total peripheral resistance

The aim of our studies was to examine if the baroreceptor reflex induced by intravenous injection of nitroglycerin (NG) nearly nullifies the vasodilator action of NG on the systemic capacitance vessels in dogs anesthetized with pentobarbital. We performed total spinal anesthesia (TSA) in open-chest dogs to eliminate the baroreceptor reflex. Dogs in which mean blood pressure (MBP) was maintained at about 100 mmHg by continuous intravenous infusion of epinephrine formed the TSA 100 group, and those in which MBP was maintained at about 70 mmHg formed the TSA 70 group. Dose-response curves relating 5-6 different doses (0.8 to 200 micrograms/kg) of intravenous NG, to changes in mean circulatory pressure (% delta MCP) and to changes in total peripheral resistance (% delta TPR), were constructed. These data were compared with those from untreated dogs. In addition, we also studied plasma catecholamine (CA) concentrations before and after the intravenous injection of NG. (1) There was no significant difference in the dose-response curves of NG for % delta TPR between the 3 groups. (2) There was no significant difference in the dose-response curves for % delta MCP between the 2 TSA groups. However, there was significant difference in the dose-response curves for % delta MCP between the TSA groups and the untreated dogs. The dose-response curves for % delta MCP in the TSA groups shifted upwards as compared with that of the untreated dogs. (3) In the TSA 100 group, there was no significant increase in the plasma CA concentrations with 100 micrograms/kg of NG. In the untreated group, intravenous injection of 12.5 micrograms/kg and 100 micrograms/kg of NG caused a dose-related fall in MBP and a dose-related rise in the plasma norepinephrine and epinephrine concentrations. Our results suggest that the vasodilator action of NG on the systemic capacitance vessels in the untreated dogs was counterbalanced partly by the vasoconstriction produced by the baroreceptor reflex, with its direct vasodilator effect masked when the hypotensive doses of NG were given acutely.

The role of alpha 1- and alpha 2-adrenoceptors in canine systemic capacitance vessels--a study with measurement of mean circulatory pressure

We investigated the presence of alpha-adrenoceptor subtypes in systemic capacitance vessels by examining the effects of alpha 1- and alpha 2-agonists or antagonists on the mean circulatory pressure (MCP). Dogs were anesthetized with pentobarbital, and after total spinal anesthesia, epinephrine was given intravenously to maintain mean blood pressure at about 80 mmHg. 1. With intravenous injection of phenylephrine (alpha 1-agonist, 10 micrograms/kg, n = 7), and of BHT 920 (alpha 2-agonist, 5 micrograms/kg, n = 7), MCP increased significantly from 9.8 +/- 0.4 (mean +/- SE) to 10.9 +/- 0.3 mmHg (+11.2%, p less than 0.01), and from 9.3 +/- 0.4 to 10.3 +/- 0.4 mmHg (+10.8%, p less than 0.05), respectively. 2. Intravenous injection of prazosin (alpha 1-antagonist, 150 micrograms/kg, n = 7) and of yohimbine (alpha 2-antagonist, 30 micrograms/kg, n = 7) decreased MCP significantly from 9.9 +/- 0.4 to 8.2 +/- 0.5 mmHg (-17.2%, p less than 0.01), and from 9.8 +/- 0.2 to 7.6 +/- 0.3 mmHg (-22.4%, p less than 0.01), respectively. 3. Intravenous injection of phenylephrine (10 micrograms/kg, n = 7) after pretreatment with prazosin (150 micrograms/kg) decreased MCP significantly from 9.5 +/- 0.3 to 7.8 +/- 0.3 mmHg (-17.9%, p less than 0.01). MCP decreased significantly from 9.9 +/- 0.3 to 8.2 +/- 0.3 mmHg (-17.2%, p less than 0.01) after intravenous injection of BHT 920 (5 micrograms/kg, n = 7) following pretreatment with yohimbine (30 micrograms/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Nicardipine inhibits the endothelin-1-induced constriction of systemic capacitance and resistance vessels

We estimated the effects of intravenous injection of endothelin-1 (ET-1; 400 pmol/kg) on the systemic capacitance and resistance vessels in anesthetized mongrel dogs by measuring changes in the mean circulatory pressure (MCP) and total peripheral resistance (TPR), respectively. In addition, the present study investigated the inhibiting action of nicardipine (NIC; 10 micrograms/kg bolus injection followed by 1.0-2.0 micrograms/kg/min continuous infusion) against the vasoconstrictor action of ET-1. We examined the effects of ET-1 (30 to 1,000 pmol/0.1 ml) on the femoral arterial system by measuring the percent changes in the perfusion pressure (% delta PP) of the femoral artery perfused with a constant flow, and investigated the effect of NIC on the vasoconstrictor action of ET-1 in this preparation. We obtained the following results: (a) Intravenous injection of ET-1 raised both TPR and MCP. However, in the presence of NIC, ET-1 raised TPR without influencing MCP. (b) Intra-arterial injection of ET-1 caused a dose-dependent increase in % delta PP. NIC shifted the dose-response curve of ET-1 for % delta PP to the right in a parallel fashion.

[Elimination of mycoplasmas from cultured human cell lines utilizing a combination of two antibiotics, quinolone and a pleuromutilin derivative]

Forty three cultured human cell lines were treated with a combination of 2 antibiotics to eliminate contaminant mycoplasmas. One course of treatment was composed of consecutive 3 or 4 cycles. Each cycle grew cells in BM-1 (pleuromutilin derivative; Boehringer Mannheim) containing medium (10 micrograms BM-1/ml culture) for 3 days, alternating with MC-210 (quinolone; Dainihon Pharmaceutical) containing medium (0.625 micrograms MC-210/ml culture) for 4 days. No treatment failure was encountered with this procedure. Before treatments, 18 (90%) of 20 cell line samples were contaminated with mycoplasma, as tested by DNA hybridization method (MYCOPLASMA T.C. RAPID DETECTION SYSTEM; Gen-Probe Inc.). Out of 43 cell lines treated, 7 were reduced in growth and dropped out. Among the other 36 cell lines, 27 became negative, 5 borderline and 4 slightly positive to the mycoplasma detection. All of the latter 9 cell lines, treated with one more similar course, found to be free from mycoplasma. Six of the dropout lines were cured of mycoplasma by a second treatment, under modified culture conditions. The last cell line (NATO) was successfully treated with another lot of FCS. Thus, the procedure proved successful even in treating promiscuously infected cell lines.

Miniature membrane oxygenator for use in neonatal ECMO

A new miniature membrane oxygenator (Kuraray KMO, size, 0.3 m2, with a priming volume of 47 ml, compliance of less than 0.1 ml/100 mmHg, and pressure loss of 45 mmHg) with improved gas transfer and mechanical durability was developed and tested. The membrane material is a hollow fiber double layer polyolefin. The testing procedures determined by the AAMI were followed, and the results showed improved O2 and CO2 transfer (70 ml/min and 55 ml/min, respectively). Hemolysis was within acceptable limits, and plasma leakage was undetectable after 7 days of perfusion. Clinical study demonstrated satisfactory performance.