Method and equipment for estimation activity nuclides in samples of finite dimensions.

This study presents a method of measuring the activity of a specific radionuclide 234mPa in samples placed in bulk transport containers under changing background conditions. The method makes it possible to measure specific activity of 234 mPa in objects without the need for sampling. The change in the effective sample volume limited by the surfaces of the containers is considered depending on the density of the measured material and the energy of gamma radiation of the radionuclide. The high sensitivity of scintillation detector, supplemented by adequate Monte Carlo simulation, allows spectrum measurements to be taken in a short time (less than an hour) with subsequent determination of specific activity. A comparison of measurement results and calculation of 234mPa activity in samples with different densities and compositions using the proposed algorithm, and those obtained by an HPGe spectrometer, demonstrated the high efficiency of the proposed solution.

Paratenon of the cruciate ligaments of the knee: a macroscopic and histological study of human foetuses.

BACKGROUND: The paratenon is a sheath-like connective tissue that allows the tendon to move with minimal friction. The careful removal of the paratenon along the cruciate ligaments is a critical step of knee surgery. Thus, orthopaedic surgeons and interventional radiologists consider the paratenon as a basic anatomical tissue along a ligament, not along a tendon. MATERIALS AND METHODS: We performed macroscopic and histological observations of cruciate ligament-associated paratenons in 43 human foetuses. RESULTS: This tissue usually had a thick armour-like appearance that was distant from the infrapatellar fat pad. The anterior cruciate ligament, rather than the posterior ligament, was deeply embedded in the paratenon. The paratenon contained abundant arteries and veins and, at and near the crossing between the cruciate ligaments, had a well-developed venous plexus. Notably, there were abundant fused veins in the paratenon venous plexus, and prenatal knee movements (especially rotation) seemed to restrict its blood supply, leading to the development of a large cavity by way of advancing fusion of veins in the degenerating plexus. This unique manner of cavitation likely expanded the joint cavity. CONCLUSIONS: Differences in knee movements in utero seemed to cause differences in the thickness of the paratenon among foetuses. New-borns might have limited knee flexion due to a mass-effect of the thick paratenon around the cruciate ligaments. A slight twisting or rotation at the knee may help to release the knee, because it can break the foetal paratenon and accelerate cavitation.

An actin barrier to resealing.

Plasma membrane disruption is a common form of cell injury in many normal biological environments, including many mammalian tissues. Survival depends on the initiation of a rapid resealing response that is mounted only in the presence of physiological levels of extracellular Ca(2+). Vesicle-vesicle and vesicle-plasma membrane fusion events occurring in cortical cytoplasm surrounding the defect are thought to be a crucial element of the resealing mechanism. However, in mammalian cells, the vesicles used in this fusion reaction (endosomes/lysosomes) are not present in a 'pre-docked' configuration and so must be brought into physical contact with one another and with the plasma membrane. We propose that a requisite prelude to fusion is the disassembly in local cell cortex of the physical barrier constituted by filamentous actin. Consistent with this hypothesis, we found that rat gastric epithelial (RGM1) cell cortical staining with phalloidin was apparently reduced at presumptive disruption sites. Moreover, flow cytofluorometric analysis of wounded RGM1 populations revealed a small, but significant, Ca(2+)-dependent reduction in whole cell phalloidin staining. The functional significance of this disruption-induced depolymerization response was confirmed in several independent tests. Introduction into RGM1 cells of the filamentous actin-depolymerizing agent, DNase1, enhanced resealing, although cytochalasin treatment, by itself, had no effect. By contrast, when the filamentous actin cytoskeleton was stabilized experimentally, using phalloidin or jasplakinolide, resealing was strongly inhibited. Cells in wounded cultures displayed an enhanced cortical array of filamentous actin, and resealing by such cells was enhanced strongly by both cytochalasin and DNase 1, demonstrating the specific reversibility of a biologically mediated, polymerization-induced inhibition of resealing. We conclude that localized filamentous actin disassembly removes a cortical barrier standing in the way of membrane-membrane contacts leading to resealing-requisite homotypic and exocytotic fusion events.

Follicular dendritic cells in vitro modulate the expression of Fas and Bcl-2 on germinal center B cells.

Germinal center (GC) B cells are highly susceptible to apoptosis. The cellular mechanism regulating this sensitivity, however, has not yet been fully delineated. To investigate whether follicular dendritic cells (FDC) are capable of regulating the susceptibility to apoptosis of GC B cells, we constructed a GC model in vitro: emperipolesis of tonsillar B cells by FDC. We then analyzed the expressions of apoptosis-related proteins (Bcl-2 and Fas) on the cells by three-color flow cytometry. B cells nonentrapped by FDC decreased rapidly in number owing to early apoptosis in vitro, whereas entrapped B cells were rescued for at least 18 h and showed peculiar regulation of Fas and Bcl-2. GC founder cells (CD38+, IgD+; GCFC) and GC B cells (CD38+, IgD-) showed approximately a twofold increased expression of Fas; in contrast, mantle zone B cells (CD38-, IgD+) and memory B cells (CD38-, IgD-) showed no changes. Bcl-2 expression in mantle zone and memory B cells was reduced by approximately one-half; however, GCFC and GC B cells continued to express little Bcl-2 and this did not change. Our findings strongly suggest that FDC play a part in the modulation of the susceptibility to apoptosis on B cells within GC.

[Considerations for community nursing care of the young advanced cancer patient].

In our unit and in general, nurses commonly take care of elderly patients. However, we herein describe the provision of community nursing care directed towards young advanced cancer patients. From our experience, the following issues should be considered by the medical care team for community nursing to be effective with these patients: Full explanation of treatment to enable the patient to make an informed decision. This can be achieved through provision of full details of the potential benefits and risks of community nursing. Next is the importance of a team based approach by the medical care team, with the support of various community and volunteer networks if necessary. Palliative care community nursing requires sincere and caring character profiles. In addition, we recognize that there are special considerations for home nursing care of the younger patient that are not present in our experience with the older patient group. One issue is that these patients have particular requirements which incur significant expenses for which there are few public support systems.

Quantitative trait loci (QTL) analysis in a Meishan x Göttingen cross population.

In order to locate the genetic regions in the swine genome that are responsible for economically important traits, a resource population has been constructed by mating two female Meishan pigs with a male Göttingen miniature pig. In subsequent generations, 265 F2 offspring were produced from two F1 males and 19 F1 females. The F2 offspring were scored for eight traits including growth rate, teat number, vertebra number and backfat thickness, and genotyped for 318 genetic markers spanning the swine genome. Least-square analysis revealed quantitative trait loci (QTL) effects for vertebra number on chromosomes 1 and 2; for teat number on chromosomes 1 and 7; for birth weight on chromosome 1; for average daily gain between 4 and 13 weeks of age on chromosomes 9 and 10; for backfat thickness on chromosome 7; and for backskin thickness on chromosome 3.

Localization of carbonic anhydrase in guinea pig Bowman's glands.

We examined the histochemical localization of carbonic anhydrase (CA) in Bowman's glands by light and electron microscopy. Neither CAI nor CAII was detected immunohistochemically in the duct cells. However, by enzyme histochemistry the duct cells revealed electron-dense precipitates demonstrative of CA in the microvilli and intercellular digitations. The reaction product was also noted in small vesicles in the cytoplasm of duct cells. In cells of the acini, the well-developed short microvilli, basolateral cell membrane, and mitochondria along the basolateral membrane showed strong deposits indicating CA activity. Dense reaction product of CA was also detected in a small core within the electron-lucent granules of the secretory cells, although CAI and CAII were not detected by immunostaining in the secretory granules. Although the functional significance of CA in Bowman's glands is obscure, the enzyme may play a role in regulation of pH and ion balance in the mucous layer covering the olfactory epithelium. The presence of CA activity in the ducts suggests that these structures are not simple tubes serving as a conduit for secretory substances but participate in modifying the luminal content by secreting CA. (J Histochem Cytochem 47:1525-1531, 1999)

Plasma membrane disruption underlies injury of the corneal endothelium by ultrasound.

The nature and the extent of acute injury to corneal endothelial cells caused by exposure to ultrasound radiation were characterized, as well as the long-term reaction of these cells to this form of injury. It was found that the degree of lethal cell injury induced by ultrasound scaled with exposure intensity and duration. Immediate changes in plasma membrane permeability were induced by ultrasound exposure. This ultrasound-induced permeability change was, however, transient in many cells, allowing them to trap and retain a normally impermeant tracer, fluorescein dextran, in cytosol. Microvilli were present on ultrasound treated cells in far greater density than on control cells, characteristic of exocytosis-based resealing. Cultures containing a majority of transiently permeabilized endothelial cells were morphologically indistinguishable from untreated control cultures, and the fluorescein dextran-labeled cells in these populations locomoted and divided normally. We conclude that cell death due to ultrasound exposure can occur rapidly via a necrotic mechanism that can be attributed to mechanically induced damage to the plasma membrane. However, not all cells injured become necrotic: some survive and appear to behave normally after exposure. Conditions that favor plasma membrane disruption resealing, e.g. that result in sub-lethal rather than lethal cell injury, may mitigate the reduction in corneal endothelial cell density consequent on phacoemulsification and aspiration surgery.

[Changes in diameter size and F-actin expression in the myocytes of patients with diabetes and streptozotocin-induced diabetes model rats].

Diabetes mellitus may be an independent risk factor for disturbance of cardiac function, but the detailed mechanism remains unclear. In the present study, histological examinations were carried out on 25 hearts from diabetes model rats as well as myocardial biopsy materials from patients with diabetes (n = 25). The mean diameter of the cardiac myocytes in humans was 12.2 +/- 0.5 microns in the control group of patients without diabetes mellitus or hypertension (n = 6), 13.7 +/- 0.8 microns in the hypertension group (n = 3), 9.0 +/- 1.7 microns in the diabetes group (n = 8), and 11.9 +/- 2.0 microns in the diabetes with hypertension group (n = 8). The cardiac myocytes of diabetic patients appeared to be atrophic. Comparison of the size of myocytes in the control rats vs streptozotocin-induced diabetes model rats (n = 7, each) was 5.4 +/- 0.2 vs 5.2 +/- 0.3 microns at 2 weeks; 5.9 +/- 0.1 vs 4.9 +/- 0.9 microns at 12 weeks, and 5.7 +/- 0.1 vs 4.0 +/- 0.2 microns at 24 weeks, respectively, and gradually decreased in streptozotocin rats with aging. Immuno-histochemistry with phaloidin was used to assess F-actin in the cardiac myocytes. The relative cross-sectional area of F-actin in the cardiac myocytes of streptozotocin rats was compared to that in non-streptozotocin rat myocytes. F-actin fluorescence in streptozotocin rats was 89.9 +/- 3.9% at 2 weeks, 77.9 +/- 6.4% at 12 weeks, and 56.8 +/- 5.7% at 24 weeks, indicating a decrease in F-actin. These results suggest that the smaller myocytes observed in patients with diabetes and streptozotocin rats are related to the decrease in F-actin in myocytes.

[The duration of action of vecuronium is unchanged when administered with propofol].

We examined the difference in the duration of action of vecuronium injected through a venous line infused with propofol and the duration of vecuronium infused into another venous line without propofol, in order to investigate the interaction between vecuronium and propofol within the intravenous lines. The subjects of the study are 8 patients, (ASA grade 1 or 2, aged from 20 to 50 years, 6 males and 2 females), who had undergone elective operations under general anesthesia. The mean duration of action of vecuronium injected through the venous line infused with propofol was 32.3 +/- 9.0 (min), while that for vecuronium injected through the venous line without propofol was 32.1 +/- 8.6 (min). There was no significant difference in the duration of action of vecuronium between the two conditions. We conclude that since vecuronium can be injected through the venous lines infused with propofol without interaction, there is no need for an additional venous line without propofol when vecuronium is administered under propofol anesthesia.

In vitro changes in the transparency and pH of cerebrospinal fluid caused by adding midazolam.

The effects of adding midazolam and bupivacaine to human cerebrospinal fluid in glass test tubes were examined by looking for changes in pH and a reduction in the transparency of the solution. Midazolam (n = 6), 0.25% bupivacaine (n = 6), 5 mg of midazolam in 6 mL of 0.25% bupivacaine (n = 6) and 5 mg of midazolam in 10 mL of saline (n = 6) were added to 1.5-mL samples (n = 24) of cerebrospinal fluid taken at the time spinal anaesthesia was begun. Transparency and pH were checked after each increment. Cerebrospinal pH was decreased to below 7.0 by adding more than 3 mg of midazolam, more than 1.9 mL of 0.25% bupivacaine or 1.3 mL of the mixture. Cerebrospinal transparency was decreased by adding more than 0.7 mg of midazolam, 1.1 mL of 0.25% bupivacaine or 0.6 mL of the mixture. Midazolam in saline neither decreased the pH below 7.0 nor reduced transparency. These results do not suggest that clinically useful doses of intrathecal or epidural midazolam are neurotoxic.

Human follicular dendritic cells in vitro and follicular dendritic-cell-like cells.

Human follicular dendritic cell (FDC)-like cells (FLC) have been utilized for the in vitro analysis of germinal center reactions. However, there is no consensus whether FLC represent FDC in vitro. The purpose of the present study has therefore been to determine distinguishing features of FDC and FLC in vitro. The expression of CD40, CD54, CD49d, cytokine (gamma-IFN and IL-4)-dependent MHC-class II, and CD106 was observed to be specific for the determination of FDC in long-term culture. The cytokine-dependent emperipolesis of germinal center B cells was establised as another discriminating property for FDC in vitro. In 2 out of 72 long-term cultures of FDC, we encountered dividing cells among the non-dividing population of FDC. The dividing cells expressed accessory molecules similar to those of FDC but showed emperipolesis only for the initial few days of their growth. FDC did not enhance the CD40-dependent proliferation of germinal center B cells; in contrast, FLC augumented it. Both types of cells produced a significant amount of cytokine-dependent IL-6. Further studies are needed to determine whether FLC originate from FDC in vitro.

Cerebrovascular CO2 reactivity in elderly and younger adult patients during sevoflurane anaesthesia.

PURPOSE: General anaesthetic agents and aging affect cerebrovascular CO2 reactivity (CCO2R). The purpose of this study was to investigate the effect of aging on CCO2R in patients during sevoflurane anaesthesia. METHODS: Twenty-four patients were divided into two groups of 12 according to age; 20-40 yr and 50-70 yr. Anaesthesia was induced with 5 mg.kg-1 thiopentone and maintained with sevoflurane 1.0 to 1.5% (end-tidal) and nitrous oxide 66% in oxygen to maintain anaesthesia. End-tidal CO2 tension (PETCO2) was altered from 20 to 50 mmHg in 5 mmHg steps by changing the respiratory rate. Middle cerebral blood flow velocity (CBFV) and pulsatility index (PI) were measured by transcranial Doppler (TCD) at each step change in PETCO2. The CCO2R was calculated as the change of CBFV per mmHg at each 5 mmHg interval. RESULTS: In each group, there were no changes in blood pressure, heart rate, end-tidal sevoflurane concentration, or PI as the PETCO2 was increased from 20 to 50 mmHg. The CCO2R at PETCO2 of 35 to 50 mmHg in the younger group (0.80 +/- 0.27 (SD) cm.sec-1.mmHg-1) was larger than that in the elderly group (0.31 +/- 0.16 cm.sec-1.mmHg-1) (P < 0.01). CONCLUSION: It is concluded that, during sevoflurane anaesthesia, CCO2R is well preserved, and that the CCO2R at PETCO2 of 35 to 50 mmHg in the 20 to 40 yr age group is greater than that in the 50 to 70 yr age group.

Inhibitory mechanism of CO2 inhalation on slowly adapting pulmonary stretch receptors in the anesthetized rabbit.

The inhibitory effects of CO2 on slowly adapting pulmonary stretch receptors (SARs) were studied before and after administration of acetazolamide, a carbonic anhydrase inhibitor, or nifedipine, a calcium channel blocker, in anesthetized, artificially ventilated rabbits after vagus nerve section. CO2 inhalation (maximal tracheal CO2 concentration ranging from 7.2% to 9.5%) for approximately 60 sec decreased the receptor activity during both inflation and deflation. The magnitude of decreased receptor activity during deflation became more pronounced than that seen during inflation. Acetazolamide treatment (20 mg/kg) diminished the inhibitory responses of slowly adapting pulmonary stretch receptors to CO2 inhalation, which were not significantly influenced by pretreatment with nifedipine (1 mg/kg). Furthermore, CO2 inhalation before and after vagal denervation had no effect on total lung resistance and dynamic lung compliance. In another series of experiments, the staining to determine the presence of carbonic anhydrase enzymatic reaction was not found in the smooth muscle of either extrapulmonary or intrapulmonary bronchi. These results suggest that CO2-induced inhibition of slowly adapting pulmonary stretch receptors is not related to the change in bronchomotor tone.

Enzyme-histochemical localization of carbonic anhydrase in the inner ear of the guinea pig and several improvements of the technique.

We have made several improvements in the method of fixation of the inner ear and the enzyme-histo-chemical technique for carbonic anhydrase (CA) detection. The results confirmed that CA is localized in the hair cells of the organ of Corti, Deiters' cells or nerve endings, inner pillar cells, Boettcher's cells, stria vascularis, spiral ligament, spiral limbus, and spiral ganglion cells. These results generally agree with previous histochemical observations but showed some differences. Our method preserved tissue morphology and showed more detailed localization of CA activity in the inner ear. In particular, the marginal zone of stria vascularis and the epithelial cells of spiral prominence, facing the endolymph, showed no CA activity, while the suprastrial region of the spiral ligament and the supralimbal region of the spiral limbus, juxtaposed to the perilymph, showed CA activity. In outer hair cells, the cuticular plate, which faces the endolymph showed CA activity, but the lateral membrane, which faces the perilymph showed no CA activity. In contrast, the inner hair cell cytoplasm showed diffuse CA activity. These results will be useful in considering ion exchange between endolymph and its adjacent cells, and between perilymph and its adjacent structures.

Histochemical localization of carbonic anhydrase in the trachea of the guinea pig.

Tissue specimens from guinea pigs were examined using an enzyme-histochemical reaction to explore the presence of carbonic anhydrase (CA) activity in the trachea. CA activity was detected in a group of morphologically distinct epithelial cells, in goblet cells, and in glands of the tracheal mucosa. The epithelial cells showing CA activity were distributed singly and sparsely throughout the entire trachea. These cells showed a wide morphological variability and were clearly different from those forming the pseudostratified ciliated epithelium. Their number was higher in sections closer to the tracheal bifurcation than in those near the larynx. Although the nature of these cells is unknown, based on their morphological and histochemical characteristics and their distribution, they may represent a specialized chemoreceptor. To our knowledge, this is the first report of CA localized in tracheal epithelial cells.

Identification of nasal epithelial cells with carbonic anhydrase activity.

Although carbonic anhydrase (CA) plays an important role in respiration, there is little information about CA in the respiratory system except for the lung. We examined the entire nasal cavity of guinea pig to identify CA activity using an enzyme-histochemical method. CA activity was detected in a group of morphologically distinct nasal epithelial cells. These cells were singly and sparsely distributed mainly in the olfactory epithelium and their number increased rostrocaudally. These cells were also detected in the apical portion of the nasal turbinate, particularly on the nasal endoturbinate, with a more complicated structure, rather than on the nasal septum and the roof of nasal cavity. Although the physiological role of these cells in unknown, based on the morphological and histochemical characteristics and the distribution of these cells, we speculated that they may represent a specialized chemoreceptors.

Follicular dendritic cells in vitro are not susceptible to infection by HIV-1.

OBJECTIVES: To investigate whether follicular dendritic cells (FDC) are target cells for HIV-1 infection. DESIGN: Based on the principle that if FDC are true target cells, HIV-1 particles will bind to the surface of FDC and then invade their cytoplasm and nuclei. METHODS: Freshly isolated tonsilar FDC were exposed to two strains (HE and JR-FL) of HIV-1 and cultured. They were then examined for HIV-1 replication, using p24 antigen-capture enzyme-linked immunosorbent assay, immunolabelling, and polymerase chain reaction (PCR) amplification. We used FDC clusters as the FDC source, since the culture system for FDC clusters has various advantages over other methods for the successful long-term culture of FDC. RESULTS: After 2 h incubation, particles of both HIV-1 strains bound to the surfaces of FDC, as well as to CD4+ T cells, although FDC do not have CD4 receptors. The FDC gradually released the particles into the culture supernatant. More HIV-1 particles were bound to fresh FDC than to dedifferentiated FDC or to control fibroblasts. However, HIV-1 particles bound to the FDC did not seem to enter the cells. We found no evidence of HIV-1 proviral DNA synthesis in FDC. CONCLUSIONS: Our results suggest that FDC are not readily infected with HIV-1 in situ, although we found that FDC in vitro were not infected by HIV-1.