Colony-stimulating factors activate human macrophages to inhibit intracellular growth of Histoplasma capsulatum yeasts

Recombinant cytokines and colony-stimulating factors (CSFs) were tested for their abilities to activate human monocytes/macrophages (M phi) to inhibit the intracellular growth of or kill Histoplasma capsulatum yeasts. None of the cytokines or CSFs or combinations of cytokines and CSFs activated M phi fungistatic activity when they were added to M phi monolayers concurrently with yeasts. In contrast, culture of monocytes for 7 days in the presence of interleukin 3, granulocyte-M phi CSF, or M phi CSF stimulated M phi fungistatic (but not fungicidal) activity against H. capsulatum yeasts in a concentration-dependent manner. Optimal activation of M phi by CSFs required 5 days of coculture, and the cultures had to be initiated with freshly isolated peripheral blood monocytes. Culture of monocytes with combinations of CSFs or addition of CSFs during the 24 h of coculture with the yeasts did not further enhance M phi fungistatic activity for H. capsulatum. Addition of gamma interferon or tumor necrosis factor alpha to CSF-activated M phi also did not enhance M phi fungistatic activity. These results suggest that interleukin 3, granulocyte-M phi CSF, and M phi CSF may play a role in the cell-mediated immune response to H. capsulatum by enhancing monocyte/M phi fungistatic activity.

Digestion of Histoplasma capsulatum yeasts by human macrophages

The strategies used by Histoplasma capsulatum yeasts to survive and multiply within human macrophages (M phi) are unknown. To better understand these strategies we studied the intracellular fate of viable vs heat-killed (HK) yeasts in human monocyte-derived M phi. Initial studies demonstrated that phagolysosome fusion was present in M phi ingesting either viable or HK yeasts. Viable yeasts multiplied within M phi phagolysosomes, whereas M phi completely digested intracellular FITC-labeled HK yeasts within 24 h after ingestion. This observation was confirmed by electron microscopy. M phi that had ingested colloidal gold-labeled HK yeasts contained gold particles but no visible yeasts at 24 h. Digestion of HK yeasts was evident as early as 4 h after phagocytosis, and was complete by 24 h. M phi digestion of HK yeasts was blocked completely when M phi were cultured for 24 h in the presence of chloroquine. In M phi simultaneously ingesting both viable and HK yeasts, viable yeasts multiplied, but HK yeasts were digested within the same cell. M phi that had ingested viable yeasts digested them completely when M phi were cultured for 24 h in the presence of cycloheximide or amphotericin B. Coculture of infected M phi with nystatin or ketoconazole resulted in inhibition of growth, but the yeasts were not digested. These data indicate that: 1), HK Hc yeasts are easily digested by preformed M phi lysosomal hydrolases; 2), viable Hc yeasts survive and multiply within M phi phagolysosomes, but the yeasts do not secrete a factor(s) that affects the ability of other phagolysosomes within the same M phi to digest killed yeasts; and 3), inhibition of yeast protein synthesis or cell wall biosynthesis is sufficient to render viable yeasts susceptible to digestion by human M phi.

Digestion of Histoplasma capsulatum yeasts by human macrophages

The strategies used by Histoplasma capsulatum yeasts to survive and multiply within human macrophages (M phi) are unknown. To better understand these strategies we studied the intracellular fate of viable vs heat-killed (HK) yeasts in human monocyte-derived M phi. Initial studies demonstrated that phagolysosome fusion was present in M phi ingesting either viable or HK yeasts. Viable yeasts multiplied within M phi phagolysosomes, whereas M phi completely digested intracellular FITC-labeled HK yeasts within 24 h after ingestion. This observation was confirmed by electron microscopy. M phi that had ingested colloidal gold-labeled HK yeasts contained gold particles but no visible yeasts at 24 h. Digestion of HK yeasts was evident as early as 4 h after phagocytosis, and was complete by 24 h. M phi digestion of HK yeasts was blocked completely when M phi were cultured for 24 h in the presence of chloroquine. In M phi simultaneously ingesting both viable and HK yeasts, viable yeasts multiplied, but HK yeasts were digested within the same cell. M phi that had ingested viable yeasts digested them completely when M phi were cultured for 24 h in the presence of cycloheximide or amphotericin B. Coculture of infected M phi with nystatin or ketoconazole resulted in inhibition of growth, but the yeasts were not digested. These data indicate that: 1), HK Hc yeasts are easily digested by preformed M phi lysosomal hydrolases; 2), viable Hc yeasts survive and multiply within M phi phagolysosomes, but the yeasts do not secrete a factor(s) that affects the ability of other phagolysosomes within the same M phi to digest killed yeasts; and 3), inhibition of yeast protein synthesis or cell wall biosynthesis is sufficient to render viable yeasts susceptible to digestion by human M phi.

Modulation of human alveolar macrophage properties by ozone exposure in vitro

We have investigated changes in human alveolar macrophage (HAM) function after exposure in vitro to ozone (O3) (0.1-1.0 ppm for 2-4 hr). The functions studied reflect concern that O3 is detrimental to host defense mechanisms in the bronchoalveolar spaces. Exposure of HAM to O3 caused a concentration-dependent increase in release of prostaglandin E2 (PGE2), an important modulator of inflammation, phagocytosis, and oxidative burst. Although phagocytosis of particulate immune complexes was decreased by O3, we found no change in the quantity of Fc receptors and complement receptors on the HAM surface. Superoxide (O2-) production in response to phorbol ester was reduced after exposure of HAM to O3 while the basal O2- release in response to plastic adherence was not affected. Growth inhibition of the opportunistic yeast Cryptococcus neoformans by HAM was not affected by O3 exposure. The production of inflammatory mediators and immune modulators such as tumor necrosis factor-alpha, interleukin 1, and interleukin 6 were not induced by exposure to O3. However, compared to controls, O3- exposed HAM produced significantly lower levels of these cytokines when stimulated with bacterial lipopolysaccharide (LPS). Two-dimensional gel electrophoretic analysis of proteins made by HAM following in vitro exposure to O3 identified 11 proteins whose rate of synthesis was significantly altered. Thus, these studies show that exposure to O3 alters the functional competence of HAM. While there is a minimal effect on protein expression or synthesis, the responses of HAM to particulate immune complexes, to bacterial LPS, and to PMA are impaired. The release of arachidonic acid and PGE2 suggest that the effect of O3 is primarily targeted to the HAM cell membrane. These changes may ultimately result in increased susceptibility to inhaled infectious agents in the O3-exposed individual.

Supportive periodontal therapy after reconstructive periodontal surgery

Clinical practice and research have established the value of supportive periodontal treatment after reconstructive periodontal surgery. The clinical procedures and the rationale for developing individualized treatments are discussed in general and for specific types of reconstructive procedures. The application of adjunctive diagnostics and chemotherapeutic agents to supplement traditional methods is described.

Differential requirements for cellular cytoskeleton in human macrophage complement receptor- and Fc receptor-mediated phagocytosis

We investigated the requirement for cellular cytoskeleton in CR- and FcR-mediated phagocytosis by human monocyte-derived macrophages (M phi). Inhibition of actin microfilament (MF) assembly and stability by cytochalasins B and D completely inhibited M phi phagocytosis of sheep E coated with C3b (EC3b), iC3b (EC3bi), and IgG (EIgG) via CR1, CR3, and FcR, respectively. Ligand-binding to either CR or FcR was not effected by cytochalasins. Nocodazole (NOC), which prevents microtubule (MT) polymerization, and taxol, which causes random polymerization of MT inhibited M phi phagocytosis of EC3b(i) but not EIgG. However, the combination of taxol (5 x 10(-4) M) and NOC (2 x 10(-6) M) augmented M phi CR-mediated phagocytosis. In addition, agents known to increase intracellular cGMP augmented phagocytosis of EC3b(i). Conversely, agents that increase intracellular cAMP inhibited CR-mediated phagocytosis. These agents had no effect on FcR-mediated phagocytosis, and did not effect ligand-binding to CR or FcR. PMA markedly enhanced CR- but not FcR-mediated phagocytosis, and augmentation of CR-mediated phagocytosis by PMA was inhibited by both CD and NOC. In contrast, the synthetic diacylglycerol, 1-oleoyl-2-acetoyl-sn-3-glycerol augmented, and inhibitors of protein kinase C inhibited M phi phagocytosis via CR and FcR. These data indicate that for adherently cultured human M phi: 1) binding of ligand-coated E to CR or FcR does not require an intact cytoskeleton; 2) intact actin microfilament are required for phagocytosis via CR and FcR; 3) phagocytosis via CR1 and CR3 but not FcR is dependent on MT assembly; 4) PMA most likely augments CR-mediated phagocytosis through promotion of MT assembly; and 5) PKC activity is involved in the phagocytic signal generated by both CR and FcR.

Differential requirements for cellular cytoskeleton in human macrophage complement receptor- and Fc receptor-mediated phagocytosis

We investigated the requirement for cellular cytoskeleton in CR- and FcR-mediated phagocytosis by human monocyte-derived macrophages (M phi). Inhibition of actin microfilament (MF) assembly and stability by cytochalasins B and D completely inhibited M phi phagocytosis of sheep E coated with C3b (EC3b), iC3b (EC3bi), and IgG (EIgG) via CR1, CR3, and FcR, respectively. Ligand-binding to either CR or FcR was not effected by cytochalasins. Nocodazole (NOC), which prevents microtubule (MT) polymerization, and taxol, which causes random polymerization of MT inhibited M phi phagocytosis of EC3b(i) but not EIgG. However, the combination of taxol (5 x 10(-4) M) and NOC (2 x 10(-6) M) augmented M phi CR-mediated phagocytosis. In addition, agents known to increase intracellular cGMP augmented phagocytosis of EC3b(i). Conversely, agents that increase intracellular cAMP inhibited CR-mediated phagocytosis. These agents had no effect on FcR-mediated phagocytosis, and did not effect ligand-binding to CR or FcR. PMA markedly enhanced CR- but not FcR-mediated phagocytosis, and augmentation of CR-mediated phagocytosis by PMA was inhibited by both CD and NOC. In contrast, the synthetic diacylglycerol, 1-oleoyl-2-acetoyl-sn-3-glycerol augmented, and inhibitors of protein kinase C inhibited M phi phagocytosis via CR and FcR. These data indicate that for adherently cultured human M phi: 1) binding of ligand-coated E to CR or FcR does not require an intact cytoskeleton; 2) intact actin microfilament are required for phagocytosis via CR and FcR; 3) phagocytosis via CR1 and CR3 but not FcR is dependent on MT assembly; 4) PMA most likely augments CR-mediated phagocytosis through promotion of MT assembly; and 5) PKC activity is involved in the phagocytic signal generated by both CR and FcR.

Inhibition of intracellular growth of Histoplasma capsulatum yeast cells by cytokine-activated human monocytes and macrophages

Human monocytes/macrophages (M psi) were infected with Histoplasma capsulatum yeast cells, and intracellular growth was quantified after 24 h of incubation in medium alone or in medium containing cytokines. Yeast cells multiplied within freshly isolated monocytes, cultured M psi, and alveolar M psi with intracellular generation times of 14.2 +/- 1.4, 18.5 +/- 2.1, and 19.9 +/- 1.9 h (mean +/- standard error of the mean), respectively. Monocytes and M psi inhibited the intracellular growth of yeast cells in response to cytokine supernatant; maximum inhibition was obtained when cytokines were added to cell monolayers immediately after infection. Opsonization of yeast cells in normal serum or in H. capsulatum-immune serum did not affect the intracellular generation time of yeast cells in either control M psi or cytokine-activated M psi.

Regulation of human monocyte/macrophage function by extracellular matrix. Adherence of monocytes to collagen matrices enhances phagocytosis of opsonized bacteria by activation of complement receptors and enhancement of Fc receptor function

In inflammation monocytes emigrate from the peripheral circulation into an extravascular area rich in extracellular matrix proteins. In this milieu, phagocytes ingest and kill invading pathogens. In the present studies, we found that monocytes adhered to type I collagen gels phagocytized 2.5-12-fold more opsonized Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae than plastic-adherent monocytes. The rate of phagocytosis and the number of bacteria ingested by collagen-adherent monocytes was equal to, or greater than, the number of bacteria ingested by 7-d cultured macrophages (M phi). Although both collagen- and plastic-adherent monocytes were bactericidal for E. coli and S. aureus, more bacteria were killed by collagen-adherent monocytes by virtue of their enhanced phagocytic capacity. Cultured M phi only were bacteriostatic. Adherence of monocytes to collagen gels activated C receptors (CR) types 1 and 3 for phagocytosis, and enhanced Fc receptor (FcR)-mediated phagocytosis. Collagen- and plastic-adherent monocytes produced equivalent amounts of superoxide anion in response to phorbol myristate acetate and opsonized zymosan. Thus, the enhanced phagocytosis and killing of opsonized bacteria by collagen-adherent monocytes appear to be by regulation of the function of membrane CR and FcR, without apparent enhancement of the respiratory burst. These data suggest that adherence of monocytes to the extracellular matrix during inflammation may rapidly activate these cells for enhanced phagocytic bactericidal activity.

The respiratory burst response to Histoplasma capsulatum by human neutrophils. Evidence for intracellular trapping of superoxide anion

Human neutrophils (PMN) have received little attention as to the role they play in host defense against Histoplasma capsulatum (Hc). We have characterized the binding and phagocytosis of Hc yeasts by human PMN and quantified the PMN respiratory burst in response to this organism. mAb specific for CD11a, CD11b, and CD11c all partially blocked the attachment of unopsonized yeasts to PMN; a mAb to CD18 inhibited attachment by greater than 90%. Thus, human PMN recognize and bind Hc yeasts via CD18 adhesion receptors as has been found for human cultured macrophages and alveolar macrophages. Unopsonized yeasts were phagocytosed by PMN, but phagocytosis was increased markedly by heat-labile and heat-stable serum opsonins. These opsonins promoted enhanced phagocytosis of yeasts by increasing the attachment of Hc yeasts to the PMN membrane. Phagocytosis of viable or heat-killed Hc yeasts by PMN did not induce the secretion of superoxide anion (O2-) as quantified by the reduction of cytochrome c. O2- was not detected when yeasts were opsonized in normal serum or immune serum, or at a ratio of yeasts to PMN of up to a 100:1. However, phagocytosis of opsonized yeasts by PMN did not prevent them from subsequently releasing O2- after further incubation with opsonized zymosan or PMA. Opsonized Hc yeasts clearly stimulated the PMN respiratory burst as quantified by intracellular reduction of nitroblue tetrazolium, reduction of cytochrome c in the presence of cytochalasin D, oxygen consumption, luminol-enhanced and nonenhanced chemiluminescence, and H2O2 production. These data suggest that phagocytosis of Hc yeasts by PMN is associated with intracellular entrapment of O2- that is not detectable by reduction of extracellular cytochrome c.

The respiratory burst response to Histoplasma capsulatum by human neutrophils. Evidence for intracellular trapping of superoxide anion

Human neutrophils (PMN) have received little attention as to the role they play in host defense against Histoplasma capsulatum (Hc). We have characterized the binding and phagocytosis of Hc yeasts by human PMN and quantified the PMN respiratory burst in response to this organism. mAb specific for CD11a, CD11b, and CD11c all partially blocked the attachment of unopsonized yeasts to PMN; a mAb to CD18 inhibited attachment by greater than 90%. Thus, human PMN recognize and bind Hc yeasts via CD18 adhesion receptors as has been found for human cultured macrophages and alveolar macrophages. Unopsonized yeasts were phagocytosed by PMN, but phagocytosis was increased markedly by heat-labile and heat-stable serum opsonins. These opsonins promoted enhanced phagocytosis of yeasts by increasing the attachment of Hc yeasts to the PMN membrane. Phagocytosis of viable or heat-killed Hc yeasts by PMN did not induce the secretion of superoxide anion (O2-) as quantified by the reduction of cytochrome c. O2- was not detected when yeasts were opsonized in normal serum or immune serum, or at a ratio of yeasts to PMN of up to a 100:1. However, phagocytosis of opsonized yeasts by PMN did not prevent them from subsequently releasing O2- after further incubation with opsonized zymosan or PMA. Opsonized Hc yeasts clearly stimulated the PMN respiratory burst as quantified by intracellular reduction of nitroblue tetrazolium, reduction of cytochrome c in the presence of cytochalasin D, oxygen consumption, luminol-enhanced and nonenhanced chemiluminescence, and H2O2 production. These data suggest that phagocytosis of Hc yeasts by PMN is associated with intracellular entrapment of O2- that is not detectable by reduction of extracellular cytochrome c.

Expression of a novel transcript of the myelin basic protein gene

A cDNA (M41) corresponding to a mouse myelin basic protein (MBP) mRNA with a longer 5'-untranslated region than predicted from earlier studies of MBP gene structure has been isolated and characterized. The additional 5'-untranslated region is encoded by two previously unidentified exons upstream of the major transcription start site of the gene. Using a DNA probe specific for M41-MBP mRNAs, Northern blot analysis indicated that expression of this transcript follows a developmental course in mouse brain similar to that of the majority of MBP mRNAs, but that the level of expression varies between brain and spinal cored. Expression of MBP mRNAs similar to the mouse M41-MBP also was identified in rat brain. The results suggest that the structure of the MBP gene is more complex than originally thought, containing at least two more exons. There appears to be at least one more MBP gene promoter that directs the synthesis of a subset of MBP mRNAs with a unique 5'-untranslated region.

Phagocytosis of Histoplasma capsulatum yeasts and microconidia by human cultured macrophages and alveolar macrophages. Cellular cytoskeleton requirement for attachment and ingestion

Phagocytosis of Histoplasma capsulatum (Hc) yeasts and microconidia by human macrophages (M phi) was quantified by a fluorescence quenching technique. Phagocytosis of unopsonized Hc yeasts by monocyte-derived M phi and human alveolar M phi (AM) was rapid. After 60 min, 79% of cultured M phi and 59% of AM had ingested an average of 9.8 and 11 yeasts/M phi, respectively. In contrast, only 26% of monocytes ingested 4.5 yeasts/cell after 60 min. Phagocytosis of unopsonized microconidia by cultured M phi and by AM was equivalent. Monoclonal antibodies specific for the alpha-chains and beta-chain of the CD18 family of adhesion receptors inhibited the binding of Hc yeasts and microconidia to cultured M phi and AM. Thus, the M phi CD18 complex mediates recognition of both phases of this dimorphic fungus. Disruption of actin microfilaments with cytochalasin D inhibited both attachment and ingestion of yeasts by M phi. In contrast, nocodazole, which prevents polymerization of microtubules, did not inhibit binding or ingestion. Both drugs inhibited ingestion, but neither drug inhibited binding of C3b- and C3bi-coated sheep erythrocytes to complement receptors type one (CR1) or type three (CR3), respectively. Therefore, different signal transducing mechanisms for phagocytosis appear to be triggered by the binding of Hc yeasts to CD18, and by the binding of EC3bi to CD11b/CD18, respectively.

Plasmin activity and complement activation during storage of citrated platelet concentrates

Platelet concentrates were studied for evidence of plasmin activity and complement activation during a 7-to-10-day storage period. When measured by an amidolytic activity assay, plasmin reached a level of 845 +/- 540 nkats/L on day 7 (n = 9). Fibrin(ogen) degradation product (FDP) levels became markedly elevated on the tenth day of storage, rising to 45 +/- 22 micrograms/ml (n = 5). Antiplasmin levels decreased in platelet concentrates by 18% +/- 6% (n = 5) over 7 days, but there was no significant decrease in stored platelet-poor plasma (-1.7%, n = 5, p = 0.5). The amount of plasminogen in platelet concentrate converted to plasmin was estimated to be less than 3% by assay of total plasminogen. Supernatant plasma from stored platelet concentrates was examined for the presence of the complement activation peptides C3a and C5a. From day 0 to day 10 of storage, mean C3a levels rose from 327 ng/ml to 6690 ng/ml. An equivalent increase in C3a levels, from 336 ng/ml at day 0 to 6866 ng/ml at day 10, was also observed in stored platelet-poor plasma. C5a was not detected (less than 10 ng/ml) at any point during the storage period; however, we noted a small decrease of borderline significance (p = 0.04) in total C5 from day 0 (117 micrograms/ml) to day 10 (108 micrograms/ml). Only trace amounts of C3 fragments were found on stored platelets, and there was no evidence of the membrane attack complex. These findings indicate the presence of plasmin activity and conversion of C3 during storage of platelet concentrates.

Negative pressure ventilation. Effects on ventilation during sleep in normal subjects

Negative pressure ventilation (NPV) is used for ventilatory support of patients with respiratory failure due to neuromuscular disorders and thoracic deformities, and to provide ventilatory muscle rest for patients with severe chronic airflow limitation. To determine whether NPV would result in episodes of upper airway obstruction during sleep, we studied five normal subjects on two consecutive nights with the first night serving as a control and NPV being administered on the second night. Ventilators were adjusted so as to reduce the peak phasic diaphragm electromyogram signal by at least 50 percent. All subjects demonstrated an increase in the total number of apneas + hypopneas per hour on NPV control nights. Although differences were not significant, there was a tendency to develop decreased sleep efficiency, sleep fragmentation and altered sleep architecture with NPV. We conclude that nocturnal NPV can induce sleep apneas and impair sleep quality in normal subjects.

Role of complement receptor type three and serum opsonins in the neutrophil response to yeast

Previous studies have suggested that neutrophil complement receptor type three (CR3) has two binding sites: (1) a site for fixed iC3b that does not trigger ingestion or a superoxide (O2-) burst, and (2) a function-triggering site for the beta-glucan component of yeast (Saccharomyces cerevisiae) cell walls. In the present study it was found that yeast (Y) coated with C3b (YC3b) or iC3b (YC3bi), prepared with purified complement in an IgG-free system, were avidly ingested ans stimulated a vigorous O2- burst, whereas sheep erythrocytes (E) bearing C3b or iC3b, were not ingested and did not give an O2- burst. YC3b and YC3bi contained an amount of fixed C3 that was approximately equal to serum-opsonized Y (OY), and produced O2- bursts comparable to OY. Experiments utilizing rabbit F(ab')2 anticomplement receptor type one (anti-CR1) to block fixed C3b binding to CR1, and monoclonal anti-CR3 (MN-41 or OKM1) to block fixed iC3b and Y cell wall binding to CR3, indicated that the O2- burst response to OY was primarily due to fixed iC3b and Y cell wall binding to CR3. Fixed C3b (that represented 33% of the fixed C3 on OY) and IgG anti-Y antibodies that bound to CR1 and Fc receptors, respectively, were found to contribute little to the response. Although YC3b did bind avidly to neutrophil CR1, the results suggested that the O2- burst response to YC3b was triggered after the initial YC3b binding by the secondary attachment of Y cell wall components to CR3. When neutrophils were treated with anti-CR3, 90% of neutrophils bound YC3b (via CR1), but phagocytosis and an O2- burst were completely absent. Similar findings were made with OKM1-treated neutrophils and YC3bi. Responses of OKM1-treated neutrophils were inhibited because only the iC3b-binding site of CR3 was ligated by the YC3bi. Thus, fixed C3b or iC3b on Y mediate avid binding of Y to neutrophils via CR1 or the iC3b-binding site of CR3, respectively, but ingestion and an O2- burst response are only triggered when glucans in the Y cell wall secondarily bind to neutrophils via the beta-glucan binding site of CR3.

Specificity of membrane complement receptor type three (CR3) for beta-glucans

The binding of the iC3b receptor (CR3) to unopsonized zymosan was shown to result from CR3 attachment to cell wall beta-glucans. A specificity of neutrophil responses for beta-glucan was first suggested by a comparison of yeast (Saccharomyces cerevisiae) cell wall components for stimulation of a neutrophil superoxide burst. Neutrophils responded poorly to heat-killed yeast, but gave increasingly better responses to cell wall polysaccharides devoid of proteins (zymosan) and nearly pure beta-glucan particles derived from zymosan. Zymosan triggered a burst that was 29% as great as that stimulated by phorbol myristate acetate (PMA), and beta-glucan particles stimulated a burst that was 72% as great as that produced by PMA. Phagocytic responses to yeast were also inhibited by soluble glucans but not by soluble mannans. Three types of experiments demonstrated a role for CR3 in these responses. First, neutrophil ingestion of either yeast or yeast-derived beta-glucan particles was blocked by monoclonal anti-CR3, fluid-phase iC3b, or soluble beta-glucan from barley. Monocyte ingestion of beta-glucan particles was also blocked by anti-CR3, but not by anti-CR1 or anti-C3. Second, the neutrophil superoxide burst response to either zymosan or beta-glucan particles was blocked by anti-CR3 or fluid-phase iC3b, and was completely absent with neutrophils from 3 patients with an inherited deficiency of CR3. Third, CR3 was isolated from solubilized neutrophils by affinity chromatography on beta-glucan-Sepharose.

Caroli's disease: new diagnostic and therapeutic approaches

Cystic dilatations of the intrahepatic and extrahepatic biliary trees are common congenital anomalies that frequently require surgical intervention. We have presented a case of Caroli's disease in which an accurate diagnosis was made noninvasively preoperatively, using computerized tomography, ultrasonography, and cholescintigraphy.

Diaphragm length and breathing pattern changes during hypoxia and hypercapnia

In this study diaphragmatic length changes were measured during quiet breathing and during augmentation of breathing with hypoxia and hypercapnia in supine anesthetized dogs. The breathing pattern and the VT-TI relationship during hypoxia were different than those during hypercapnia. The crural diaphragm shortened more than the costal diaphragm with both stimuli, and the amount of shortening in relation to the tidal volume implied that there was considerable distortion of the chest wall during hyperventilation. The velocity of shortening of both parts of the diaphragm at similar levels of ventilation was greater during hypoxia than hypercapnia. The velocities found with hyperventilation suggested that force-velocity considerations did not reduce force generation. Hypoxic stimulation resulted in a reduction in the resting length of both parts of the diaphragm, and was associated with a positive shift in baseline pleural pressure which implied gas trapping. The large tidal diaphragmatic shortening found with augmented breathing and the shorter resting length with hypoxia indicated that length-force properties are important in force generation.

Assignment of the rhodopsin gene to human chromosome 3

The human rhodopsin gene has been assigned to human chromosome 3 through the use of a mouse DNA probe and human/mouse somatic cell hybrids.

Natural history of symptomatic partial ornithine transcarbamylase deficiency

We reviewed the natural history and differential diagnosis of ornithine transcarbamylase deficiency (an X-linked inborn error of urea synthesis) in 13 symptomatic female heterozygotes. The patients presented as early as the first week of life or as late as the sixth year. The most common symptoms before diagnosis were nonspecific: episodic extreme irritability (100 percent), episodic vomiting and lethargy (100 percent), protein avoidance (92 percent), ataxia (77 percent), Stage II coma (46 percent), delayed physical growth (38 percent), developmental delay (38 percent), and seizures (23 percent). Including the proband, 42 percent of the female members of the 13 families studied had symptoms. The median interval between the onset of major symptoms (vomiting and lethargy, seizures, and coma) and diagnosis was 16 months (range, 1 to 142). Five patients had IQ scores below 70 at the time of diagnosis. We suggest that careful evaluation of the family history, the dietary history, the episodic nature of the nonspecific symptoms, the response of these symptoms to the withdrawal of protein, and their frequent onset at the time of weaning from breast milk will permit early diagnosis and might thereby reduce the risk of death or neurologic impairment in female patients with partial ornithine transcarbamylase deficiency.

In vivo length and shortening of canine diaphragm with body postural change

Using sonomicrometry, we measured the in vivo tidal shortening and velocity of shortening of the costal and crural segments of the diaphragm in the anesthetized dog in the supine, upright, tailup, prone, and lateral decubitus postures. When compared with the supine position, end-expiratory diaphragmatic length varied by less than 11% in all postures, except the upright. During spontaneous breathing, the tidal shortening and the velocity of shortening of the crural segment exceeded that of the costal segment in all postures except the upright and was maximal for both segments in the prone posture. We noted the phasic integrated electromyogram to increase as the end-expiratory length of the diaphragm shortened below and to decrease as the diaphragm lengthened above its optimal length. This study shows that the costal and crural segments have a different quantitative behavior with body posture and both segments show a compensation in neural drive to changes in resting length.

Resolution of the clinical features of tyrosinemia following orthotopic liver transplantation for hepatoma

The clinical history before transplantation and subsequent clinical and biochemical course of 3 children and one adult with hereditary tyrosinemia treated by orthotopic hepatic transplantation is described. All four patients are now free of their previous dietary restrictions and appear to be cured of both their metabolic disease and their hepatic neoplasm.