Oligodendrocytes and myelin formation along the optic tract of the developing hamster: an immunohistochemical study using the Rip antibody

The monoclonal antibody Rip recognizes an antigen specific to oligodendrocytes and their processes (Friedman et al: Glia 2:380, 1989). We have used this antibody to document the appearance of oligodendrocytes and the sequence of ensheathment of axons along the optic tract (OT) and within its major target areas in neonatal (P3-P21) and adult hamsters. Myelination of axons in the visual pathway follows an overall proximo-distal gradient. On P3, immunopositive, pre-ensheathing oligodendrocytes are detected in the OT ventral to the lateral geniculate body (LGB) whereas myelin segments are present around OT axons by P5. The first pre-ensheathing oligodendrocytes are detected medially in the LGB on P7 and myelinated axons in the overlying OT by P11. In the superior colliculus, pre-ensheathing oligodendrocytes are present in the optic fiber layer (SO) on P7, but not in the superficial gray layer (SGS) until P11. Myelination of axons within SO proceeds along a marked rostro-caudal gradient. On P14, axons in rostral SO are heavily myelinated; thereafter, ensheathment continues caudally within the SO and the SGS. The progressive invasion of oligodendrocytes along the proximo-distal axis of the optic pathway, and the corresponding myelination of OT axons, are discussed in the context of a possible inhibitory role of oligodendrocytes in regulating the regenerative propensity of retinotectal axons.

Episodic eosinophilia-myalgia-like syndrome in a patient without L-tryptophan use: association with eosinophil activation and increased serum levels of granulocyte-macrophage colony-stimulating factor

We have studied a patient with recurrent bouts of angioedema, myalgia, and eosinophilia that was not due to L-tryptophan ingestion. Peripheral blood eosinophils (EOSs) during exacerbations of his illness displayed characteristics of "activation," including hypodense phenotype and increased responsiveness to platelet-activating factor (PAF) in vitro with respect to expression of CD11b surface adhesion proteins. Elevated serum levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) bioactivity were also detected, whereas interleukin-3 and interleukin-5 levels were not increased. During treatment with glucocorticoids, all clinical symptoms resolved, EOSs decreased in number and became normodense, PAF responsiveness diminished, and GM-CSF levels returned to normal. During glucocorticoid tapering, a subsequent clinical relapse was again associated with EOS hypodensity, increased PAF responsiveness, and increased serum GM-CSF levels. Although this patient satisfies the diagnostic criteria for eosinophilia-myalgia syndrome, the episodic and profound nature of exacerbations and response to therapy in the absence of L-tryptophan usage suggests a possible overlap with the syndrome of episodic angioedema and eosinophilia. In vitro studies suggest that GM-CSF may play a role in the eosinophilia, EOS activation, and pathophysiology of disease in this patient and demonstrate resolution of these abnormalities during glucocorticoid therapy. The efficacy of glucocorticoid therapy in some hypereosinophilic states may therefore be mediated, at least in part, via reduction of GM-CSF production and/or EOS activation.

Case management: a randomized controlled study comparing a neighborhood team and a centralized individual model

This randomized controlled study compared two types of case management for skilled nursing level patients living at home: the centralized individual model and the neighborhood team model. The team model differed from the individual model in that team case managers performed client assessments, care planning, some direct services, and reassessments; they also had much smaller caseloads and were assigned a specific catchment area. While patients in both groups incurred very high estimated health services costs, the average annual cost during 1983-85 for team cases was 13.6 percent less than that of individual model cases. While the team cases were 18.3 percent less expensive among "old" patients (patients who entered the study from the existing ACCESS caseload), they were only 2.7 percent less costly among "new" cases. The lower costs were due to reductions in hospital days and home care. Team cases averaged 26 percent fewer hospital days per year and 17 percent fewer home health aide hours. Nursing home use was 48 percent higher for the team group than for the individual model group. Mortality was almost exactly the same for both groups during the first year (about 30 percent), but was lower for team patients during the second year (11 percent as compared to 16 percent). Probable mechanisms for the observed results are discussed.

Selective metal binding to Cys-78 within endonuclease V causes an inhibition of catalytic activities without altering nontarget and target DNA binding

T4 endonuclease V is a pyrimidine dimer-specific DNA repair enzyme which has been previously shown not to require metal ions for either of its two catalytic activities or its DNA binding function by virtue of its ability to function in the presence of metal-chelating agents. However, we have investigated whether the single cysteine within the enzyme was able to bind metal salts and influence the various activities of this repair enzyme. A series of metals (Hg2+, Ag+, Cu+) were shown to inactivate both endonuclease Vs pyrimidine dimer-specific DNA glycosylase activity and the subsequent apurinic nicking activity. The binding of metal to endonuclease V did not interfere with nontarget DNA scanning or pyrimidine dimer-specific binding. The Cys-78 codon within the endonuclease V gene was changed by oligonucleotide site-directed mutagenesis to Thr-78 and Ser-78 in order to determine whether the native cysteine was directly involved in the enzyme's DNA catalytic activities and whether the cysteine was primarily responsible for the metal binding. The mutant enzymes were able to confer enhanced ultraviolet light (UV) resistance to DNA repair-deficient Escherichia coli at levels equal to that conferred by the wild type enzyme. The C78T mutant enzyme was purified to homogeneity and shown to be catalytically active on pyrimidine dimer-containing DNA. The catalytic activities of the C78T mutant enzyme were demonstrated to be unaffected by the addition of Hg2+ or Ag+ at concentrations 1000-fold greater than that required to inhibit the wild type enzyme. These data suggest that the cysteine is not required for enzyme activity but that the binding of certain metals to that amino acid block DNA incision by either preventing a conformational change in the enzyme after it has bound to a pyrimidine dimer or sterically interfering with the active site residue's accessibility to the pyrimidine dimer.

Clinical and biochemical effects of an oral leukotriene biosynthesis inhibitor (MK886) in psoriasis

Antipsoriatic agents have been shown to decrease skin levels of arachidonic acid and its metabolites including 12-monohydroxy-eicosatetranoic acid (12-HETE), and leukotriene B4 (LTB4). In addition, specific systemic and topical lipoxygenase inhibitors have been reported to be effective in the treatment of psoriasis. The objective of this study was to investigate the effect of a potent oral leukotriene biosynthesis inhibitor (MK886) in patients with chronic plaque psoriasis. Clinical response together with the changes of LTB4 levels in lesional skin biopsy specimens, and urinary leukotriene E4 (LTE4) excretion were evaluated. In addition, markers of inflammation, proliferation and keratinization were studied immunohistochemically. No change in clinical scores or lesional LTB4 levels were observed with a 10 1/3-day course of MK886. A statistically significant reduction in urinary LTE4 excretion was observed: mean LTE4 (ng/h) were 5.14 before treatment and 1.51 on day 11 with MK886; and 7.55 before treatment and 6.57 on day 11 with placebo treatment. Epidermal accumulation of polymorphonuclear leukocytes (PMN) tended to diminish in the MK886 treatment group. These results indicate that although a reduction (greater than 70%) in urinary LTE4 excretion was found, and a slight decrease of epidermal PMN accumulation was observed, no correlative changes in clinical scores or LTB4 levels in skin lesion were found with a short course of MK886.

NT-3, BDNF, and NGF in the developing rat nervous system: parallel as well as reciprocal patterns of expression

To obtain insight into the site and stage specificity of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) action in vivo, we compared the expression patterns of the genes for these three related neurotrophic factors as well as for the NGF receptor in developing and adult rats. Initial embryonic expression of these related neurotrophic factors approximately coincides with the onset of neurogenesis. However, the levels at which the three factors are expressed at this time and throughout the developing nervous system are dramatically different. NT-3 is by far the most highly expressed in immature regions of the CNS in which proliferation, migration, and differentiation of neuronal precursors is ongoing. NT-3 expression dramatically decreases with maturation of these regions. By contrast, BDNF expression is low in developing regions of the CNS and increases as these regions mature. NGF expression varies during the development of discrete CNS regions, but not in any consistent manner compared with NT-3 and BDNF. Despite the dramatic variations, NT-3, BDNF, and NGF do share one striking similarity--high level expression in the adult hippocampus. Our observations are consistent with the idea that NT-3, BDNF, and NGF have paralleled as well as reciprocal roles in vivo.

Septic arthritis of the sternoclavicular joint in healthy adults

Septic arthritis of the sternoclavicular joint (SCJ) is a rare disorder, and is usually associated with predisposing factors such as contiguous foci of infection, heroin addiction, rheumatoid arthritis and diabetes mellitus. Three cases in previously healthy adults are reported here. The aetiology, clinical manifestations and treatment are briefly reviewed. The considerable difficulty in diagnosing this disorder in adults is emphasized. In summary, diagnosis of septic arthritis of the SCJ in adults requires a high index of suspicion, and must be considered not only in patients with predisposing factors, but also in previously healthy adults.

Acute theophylline toxicity and the use of esmolol to reverse cardiovascular instability

Theophylline overdoses are frequent conditions that may require emergency treatment. Clinical features common to severe theophylline toxicity include nausea and vomiting, tachydysrhythmias, metabolic disturbances, seizures, and cardiovascular collapse. Several reports have described these manifestations and their treatments. We report the case of a patient suffering from an acute, intentional theophylline overdose who exhibited the classic features of a toxic ingestion and describe the first reported use of IV esmolol in the treatment of accompanying cardiovascular manifestations.

Monoclonal antibody rat 401 recognizes Schwann cells in mature and developing peripheral nerve

Monoclonal antibody Rat 401 recognizes subsets of cells in the developing central and peripheral nervous systems. Previous studies have shown that in the central nervous system (CNS) Rat 401 immunoreactivity diminishes sharply with cellular differentiation. Here we have examined the time course, cellular localization, and biochemical nature of the Rat 401 antigen in the rat peripheral nerve. In contrast to the CNS, in the periphery Rat 401 immunoreactivity is maintained into adulthood. Rat 401 staining is restricted to Schwann cells in mature peripheral nerve. Myelin-related Schwann cells are intensely immunoreactive, whereas nonmyelin-related Schwann cells are weakly immunoreactive. Unlike many Schwann cell markers, Rat 401 staining is maintained in cultured Schwann cells that lack axon contact. Biochemical analyses show that the antigen recognized by Rat 401 in the peripheral nerve is identical to that in embryonic CNS. The results demonstrate that the capacity for maintained Rat 401 immunoreactivity is restricted to Schwann cells as these cells are stained in adult animals as well as in embryos. In contrast, the same antigens are lost from the CNS at an early stage of development.

Care for the underinsured: who should pay?

Inner-city medically underinsured adults describe their preferences for health care and willingness to pay for health care services. The responses of 146 patients attest to the burden of administrative and economic responsibility placed on the public health care sector for indigent patient care. The results of this survey address the information required by the nurse managers who must balance patient needs against administrative pressures to generate revenue from patient fees.

Regulation of the epidermal growth factor receptor by growth-modulating agents: effects of staurosporine, a protein kinase inhibitor

Staurosporine is a potent microbial inhibitor of a number of protein kinases, including protein kinase C, cyclic AMP-dependent kinase, and the tyrosine kinase pp60src. We have used staurosporine to investigate the role of phosphorylation in the regulation of the epidermal growth factor (EGF) receptor in both human epidermal carcinoma A431 cells and mouse Swiss 3T3 fibroblasts. We report here that staurosporine treatment causes enhancement in high affinity EGF binding and a decrease in the phosphorylation state of the unstimulated receptor at a number of residues, including threonine 669. Staurosporine also antagonizes the inhibition of high affinity EGF binding and the increase in phosphorylation state of the unstimulated EGF receptor by phorbol esters and the calcium ionophore A23187. Staurosporine is an effective inhibitor of the EGF-stimulated receptor tyrosine kinase in vitro and thus does not enhance EGF stimulation of EGF receptor autophosphorylation in vivo. These results suggest that phosphorylation plays a major role in the regulation of the high affinity binding state of the EGF receptor in both unstimulated and mitogenically activated cells.

Basic fibroblast-like growth factor is present in the conditioned medium of simian sarcoma virus transformed NRK cells

The conditioned medium of Simian sarcoma virus (SSV)-transformed NRK cells contains at least two activities that down regulate the epidermal growth factor receptor. To identify these activities, we analyzed the medium for the presence of factors both related to and distinct from the v-sis oncogene product. Fractionation of the conditioned medium from SSV-transformed NRK cells by chromatography on heparin-Sepharose yielded two active fractions capable of inhibiting EGF binding. The first component, which eluted at 0.8 M NaCl, is able to induce autophosphorylation of the platelet-derived growth factor (PDGF) receptor, is a mitogen for Swiss 3T3 cells and corresponds to the PDGF B chain product of the v-sis oncogene. The second component requires 2 M NaCl for elution, is mitogenic for Swiss 3T3 cells and inhibits high affinity EGF binding through a protein kinase C-independent pathway, all properties of basic FGF. These results suggest that the conditioned medium of v-sis-transformed cells contains at least two factors that can act in an autocrine capacity, one derived from v-sis and one corresponding to basic FGF.

Tumoral calcinosis simulating osteomyelitis

A case of tumoral calcinosis simulating osteomyelitis and associated with bunion formation in a 20-year-old female is presented. The most striking findings in this patient were the soft tissue calcifications. There was no evidence of any of the known causes of heterotopic calcifications. This kind of simulation between tumoral calcinosis bunion formation and osteomyelitis has not been previously described.

Basic and acidic fibroblast growth factors modulate the epidermal growth factor receptor by a protein kinase C-independent pathway

Human acidic and basic fibroblast growth factors (aFGF and bFGF) inhibit epidermal growth factor (EGF) receptor binding in mouse Swiss 3T3 cells. Scatchard analysis indicates that aFGF and bFGF cause a decrease in the high affinity EGF receptor population, similar to that observed for activators of protein kinase C such as phorbol esters, platelet-derived growth factor (PDGF) and bombesin. However, unlike phorbol esters, aFGF and bFGF inhibit EGF binding in protein kinase C-deficient cells. The time course and dose response of inhibition of EGF binding by both aFGF and bFGF are very similar, with an ID50 of approximately 0.10 ng/ml. In contrast to bombesin but like PDGF, neither aFGF nor bFGF act on the EGF receptor through a pertussis toxin-sensitive G protein. These results indicate that both acidic and basic FGF depress high affinity EGF binding in Swiss 3T3 cells with similar potency through a protein kinase C/Gi-independent pathway.

Immuno-ultrastructural localization of sodium channels at nodes of Ranvier and perinodal astrocytes in rat optic nerve

Immuno-electron microscopic localization of sodium channels at nodes of Ranvier within adult optic nerve was demonstrated with polyclonal antibody 7493. The 7493 antisera, which is directed against purified sodium channels from rat brain, recognizes a 260 kDa protein in immunoblots of the crude glycoprotein fraction from adult rat optic nerve. Intense immunoreactivity with 7493 antisera was observed at nodes of Ranvier. Axon membrane at the node was densely stained, whereas paranodal and internodal axon membrane did not exhibit immunoreactivity. The axoplasm beneath the nodal membrane displayed variable immunostaining. Neither terminal paranodal oligodendroglial loops nor oligodendrocyte plasmalemma were immunoreactive with 7493 antisera. However, perinodal astrocyte processes exhibited intense immunoreactivity with the anti-sodium channel antisera. Optic nerves incubated with pre-immune sera, or with 7493 antisera that had been pre-adsorbed with purified sodium channel protein, displayed no immunoreactivity. These results demonstrate localization of sodium channels at high density at mammalian nodes of Ranvier and in some perinodal astrocyte processes. The latter observation offers support for an active role for perinodal astrocyte processes in the aggregation of sodium channels within the axon membrane at the node of Ranvier.

Regulation of human basophil mediator release by cytokines. I. Interaction with antiinflammatory steroids

We have analyzed the effects of overnight culture of human basophils with a variety of cytokines in the presence or absence of the glucocorticoid dexamethasone. The 24-h culture of basophils with a range of concentrations of several cytokines (granulocyte-macrophage-CSF, TNF-alpha, IL-1, IL-2, and IL-4) had no effect either on anti-IgE-induced histamine release or the inhibitory effects of dexamethasone on histamine release. IFN-gamma enhanced postculture releasability of human basophils. The concentration range for this effect was from 50 to 50,000 U/ml and maximal enhancement of anti-IgE-induced basophil histamine release was approximately 200% of control. IFN-gamma did not increase the number of occupied or unoccupied Fc epsilon RI on human basophils, suggesting that the enhancement of histamine release is a result of an intrinsic increase in the releasability mechanism. rIL-3 also augmented basophil releasability (approximately 250% of control) by a mechanism independent of alterations in basophil cell surface IgE density. The increase in post culture releasability occurred in both partially purified basophils (12 to 90% purity) and mixed leukocytes (approximately 1% basophils) although it was more marked in the former. Enhanced postculture releasability after exposure to IL-3 occurred for both IgE-dependent (anti-IgE) and peptide-mediated (fmet-leu-phe) responses and included elevations in the release of both histamine and sulfidopeptide leukotriene, suggesting a global increase in releasability. Basophils cultured in the presence of IL-3 were insensitive to the inhibitory effects of dexamethasone; at 1,000 U/ml IL-3, dexamethasone inhibition of basophil mediator release was completely blocked. None of the other cytokines tested, with the exception of crude or partially purified IL-2 preparations, had this effect. IL-3 contamination may explain the ability of these partially purified "IL-2" preparations to block the inhibitory effects of dexamethasone, because this effect was abolished by a specific anti-IL-3 antibody. These results suggest that IFN-gamma and IL-3 may modulate the response of human basophils in allergic reactions. Furthermore, increased local production of IL-3 may "prime" basophils for increased releasability and override inhibitory effects of elevated systemic glucocorticoids on human basophils. Finally, we conclude that the effects of glucocorticoids on human basophils may be in part mediated indirectly by effects on cells which produce cytokines, such as IFN-gamma and IL-3, that can modulate basophil function.

Regulation of human basophil mediator release by cytokines. I. Interaction with antiinflammatory steroids

We have analyzed the effects of overnight culture of human basophils with a variety of cytokines in the presence or absence of the glucocorticoid dexamethasone. The 24-h culture of basophils with a range of concentrations of several cytokines (granulocyte-macrophage-CSF, TNF-alpha, IL-1, IL-2, and IL-4) had no effect either on anti-IgE-induced histamine release or the inhibitory effects of dexamethasone on histamine release. IFN-gamma enhanced postculture releasability of human basophils. The concentration range for this effect was from 50 to 50,000 U/ml and maximal enhancement of anti-IgE-induced basophil histamine release was approximately 200% of control. IFN-gamma did not increase the number of occupied or unoccupied Fc epsilon RI on human basophils, suggesting that the enhancement of histamine release is a result of an intrinsic increase in the releasability mechanism. rIL-3 also augmented basophil releasability (approximately 250% of control) by a mechanism independent of alterations in basophil cell surface IgE density. The increase in post culture releasability occurred in both partially purified basophils (12 to 90% purity) and mixed leukocytes (approximately 1% basophils) although it was more marked in the former. Enhanced postculture releasability after exposure to IL-3 occurred for both IgE-dependent (anti-IgE) and peptide-mediated (fmet-leu-phe) responses and included elevations in the release of both histamine and sulfidopeptide leukotriene, suggesting a global increase in releasability. Basophils cultured in the presence of IL-3 were insensitive to the inhibitory effects of dexamethasone; at 1,000 U/ml IL-3, dexamethasone inhibition of basophil mediator release was completely blocked. None of the other cytokines tested, with the exception of crude or partially purified IL-2 preparations, had this effect. IL-3 contamination may explain the ability of these partially purified "IL-2" preparations to block the inhibitory effects of dexamethasone, because this effect was abolished by a specific anti-IL-3 antibody. These results suggest that IFN-gamma and IL-3 may modulate the response of human basophils in allergic reactions. Furthermore, increased local production of IL-3 may "prime" basophils for increased releasability and override inhibitory effects of elevated systemic glucocorticoids on human basophils. Finally, we conclude that the effects of glucocorticoids on human basophils may be in part mediated indirectly by effects on cells which produce cytokines, such as IFN-gamma and IL-3, that can modulate basophil function.

Geographic differences in the use of Veterans Administration hospitals

This study contrasts the determinants of community hospital utilization with Veterans Administration (VA) hospital utilization using traditional planning variables. The comparisons had some expected and some unanticipated findings. Regional differences in non-VA hospital admissions and bed days are fairly well explained by measures of medical need, provider supply, community alternatives, and sociodemographic characteristics (other than those used as proxies for case mix). However, regional variations in the VA are explained less well by the same classes of variables and the unexplained differences between the two systems do not correspond geographically. This suggests that the two systems have different reasons for regional variation. Further, contrary to expectation, when other predictors are held constant, excess bed capacity in the area does not correlate with lower VA utilization. The study is important as the VA comes under increasing pressure to contain costs. It may well be that the rational planning model attributed to the public sector is less likely to overcome maldistribution than the private sector 'invisible hand'. Policy analysts need to give more attention to the political, bureaucratic determinants of resource allocation before changing eligibility criteria or merging the two systems.

Antigenic abnormalities in fiber tract astrocytes of myelin-deficient rats: an immunocytochemical study in the olfactory cortex

Intrafascicular oligodendrocytes in myelin-deficient (md) rats typically fail to form myelin sheaths or survive to maturity. The present study of the md olfactory cortex compares astrocytes that develop either among populations of pathological oligodendrocytes in a fiber tract or that develop in neuropil, which normally contains few oligodendrocytes. Antigenic profiles for md and normal astrocytes were defined by the monoclonal antibody Rat 401, and by antibodies that recognize vimentin and glial fibrillary acidic protein. In the olfactory cortex, antigenic abnormalities were typically restricted to astrocytes located in the vicinity of pathological oligodendrocytes.

Sodium channels in astrocytes of rat optic nerve in situ: immuno-electron microscopic studies

Immuno-electron microscopic localization of sodium channels within astrocyte somata and processes of adult rat optic nerve was demonstrated with polyclonal antibody 7493. In immunoblots of crude glycoproteins from adult rat optic nerve, antisera 7493, which is directed against purified rat brain sodium channels, recognizes a 260 kDa protein. Antisera 7493 intensely immunostains axon membrane at nodes of Ranvier. Associated perinodal astrocyte processes are also stained with antisera 7493. In addition, astrocyte cell bodies and major processes exhibit immunoreactivity with antibody 7493. Immunostaining with antisera 7493 is heterogeneously distributed within astrocyte cytoplasm and also appears to be associated with some regions of astrocyte plasmalemma. Glial filaments are not immunostained with 7493 antisera. Astrocyte processes forming the glial limitans and surrounding blood vessels display reduced immunoreactivity to 7493 compared to longitudinally oriented or perinodal astrocyte processes. However, some focal regions of the glial limitans exhibit robust 7493 immunostaining. Oligodendrocytes do not display 7493 antisera immunoreactivity. Optic nerve sections incubated with preimmune sera or with 7493 antisera that had been previously adsorbed with purified sodium channel protein, exhibited no immunoreactivity. These results demonstrate localization of sodium channels within astrocytes in situ of rat optic nerve and extend previous electrophysiological and pharmacological findings of sodium channels in cultured astrocytes. Possible functional roles of sodium channels within astrocytes are discussed.

In situ demonstration of mature oligodendrocytes and their processes: an immunocytochemical study with a new monoclonal antibody, rip

This paper introduces "Rip" a monoclonal antibody that produces relatively complete staining of oligodendrocytes and their processes in the adult central nervous system (CNS). The distribution of Rip immunoreactivity coincides with that of myelinated axons in both the spinal cord and the cerebellum. In addition, double-immunolabeling experiments demonstrate that Rip stains processes containing myelin basic protein but does not stain processes that express glial fibrillary acidic protein. These results indicate that Rip selectively stains oligodendrocytes but not astrocytes. Moreover, individual Rip-stained oligodendrologial somata and their cytoplasmic processes were observable at both the light microscopic and electron microscopic level when the staining of myelin was reduced. This was accomplished by omitting detergents from antibody incubation steps. Rip-stained oligodendrocytes have multiple processes of varying thickness, some of which end in close proximity to myelin sheaths. These immunostained profiles, reminiscent of those observed in oligodendrocytes stained by Golgi methods, are unique to Rip and indicate that its immunoreactivity is distinct from that of existing serological markers for oligodendrocytes.

Thapsigargin, a novel promoter, phosphorylates the epidermal growth factor receptor at threonine 669

Thapsigargin, a protein kinase C-independent tumor promoter, can negatively regulate the epidermal growth factor (EGF) receptor through inhibition of high affinity EGF binding and EGF-stimulated tyrosine kinase activity. In contrast to activators of protein kinase C, thapsigargin does not induce significant phosphorylation of threonine 654. However, thapsigargin does stimulate phosphorylation of the EGF receptor at other serine and threonine residues. We now identify threonine 669 as the major site of phosphorylation on the EGF receptor resulting from thapsigargin treatment. These results raise the possibility that phosphorylation of threonine 669 may mediate changes in the binding and kinase state of the EGF receptor.

Prolonged corticosteroid treatment in the management of temporal arteritis

Twenty-four patients with biopsy proven temporal arteritis were followed for 7 years and the effect and duration of corticosteroid treatment was evaluated. An initial dose of 35 mg prednisone daily was sufficient to control symptoms and signs in most of the patients. Flare-up rates upon corticosteroid reduction were high, especially in the first 24 months of treatment. Flare-ups were more common (greater than twice) in "non-western" Jews as compared to "western" Jews. Serious corticosteroid side effects were uncommon. Corticosteroid treatment was withdrawn from 7 patients after 5 years; two of these patients suffered flare-ups within 16 months. Nineteen patients remained on prednisone, in an average dose of 4 mg/day, 7 years after diagnosis. Thus, corticosteroid treatment in temporal arteritis should be prolonged in the majority of patients.

The need for special interventions for multiple hospital admission patients

Although a high proportion of Medicare hospital admissions and expenditures are accounted for by a small proportion of the elderly who experience chronic patterns of acute hospital use, little emphasis has been placed on reducing hospitalization among these high users. Five interventions that have succeeded in substantially reducing the number of hospital days among high users living at home are discussed in this article, as are several interventions that have reduced hospital use by nursing home residents. With the passage of the Medicare Catastrophic Coverage Act of 1988, research and demonstration activities for high users of hospital care will, for the first time, have a Federal focus.

Synovial chondromatosis of the hip joint

Synovial chondromatosis of the hip joint is uncommon entity. Two cases are presented, and the spectrum of the disease is discussed. Partial synovectomy with loose body removal is recommended as the treatment of choice. Joint replacement is performed only in patients with severe secondary osteoarthritis, and used only in selected cases.

Scintigraphic presentation of hip joint synovial chondromatosis

A case of hip joint synovial chondromatosis with an unusual scintigraphic pattern is described. This pattern was suggestive of a hip joint destructive reactive articular process or late manifestations of avascular necrosis of the femoral head. Concurrent radiographs were normal, as were laboratory investigations. Follow-up radiographs six months later showed radiolucencies and erosive bone changes in the diseased joint. Surgical and histopathological findings revealed well developed hip synovial chondromatosis (HSC) with thickened synovium and large, loose, cartilaginous bodies occupying and widening the tightened joint space, with destructive secondary juxta articular pressure and bone erosions. This and other scintigraphic patterns in HSC, and the differential diagnosis of the findings in patients with painful hip presentations are discussed.

The financial performance of selected investor-owned and not-for-profit system hospitals before and after Medicare prospective payment

This article analyzes determinants of cost and profitability, including the influence of Medicare prospective payment (PPS), between 1983 and 1985 for nearly 300 hospitals belonging to investor-owned (IO) and not-for-profit (NFP) systems. Using approaches that assure comparability of financial data, and including case mix, quality, competition, and regulation measures, the findings indicate that (1) in both years, competitive environment, case mix, age of facility, and scope of diversified services were important determinants of average cost, while a process measure of quality was insignificant and the independent effect of ownership type was insignificant for cost; (2) effects of HMO competition and hospital strategy were stronger in 1985 than in 1983; (3) operating margins for all types of hospitals showed increases, with a somewhat greater improvement for NFP system members; and (4) significantly greater declines in volume of care occurred for IO system members. Implications for future research are discussed.

Transferrin iron interactions with cultured hepatocellular carcinoma cells (PLC/PRF/5)

Hepatocellular carcinoma cells of the PLC/PRF/5 cell line had 1.9 x 10(5) transferrin receptors per tumor cell with a Kd of 1.5 x 10(-8) M. At high concentrations of transferrin the binding was not saturable. Transferrin internalization by hepatoma cells was shown by time and temperature-dependent binding studies and by pronase experiments. Transferrin recycling was confirmed by the demonstration of a progressive increase in the cellular molar ratios of iron to transferrin and by chase experiments. Ammonium chloride interfered with iron unloading. The vinca alkaloid vincristine inhibited iron and transferrin uptake. The hepatocarcinoma cells appeared to lack asialoglycoprotein receptors and therefore internalized partially desialated transferrin by the regular route. Iron uptake from transferrin was markedly inhibited by the hydrophobic ferrous chelator 2,2' bipyridine but was relatively unaffected by the hydrophilic ferric chelator desferroxamine. The implication that ferrous iron was involved in postendocytic transvesicular membrane iron transport was supported by a study in which hepatoma cells were shown to take up large amounts of ferrous iron suspended in 270 mM sucrose at pH 5.5. The interaction at this pH between surface labeled hepatoma cell extracts and ferrous iron on a Sephacryl S-300 column suggested that the postendocytic transvesicular transport of iron through the membrane was in part protein mediated. The endocytosed iron in hepatoma cells was found in association with ferritin (33%), transferrin (31%) and a low molecular weight fraction (21%).

Effect of coronary artery revascularization on left and right ventricular ejection fractions during rest and exercise

We have reported a case of a 55-year-old man who had improvement of both left and right ventricular ejection fractions during rest and exercise after coronary revascularization. Ventricular performance was assessed using radionuclide angiography. Although coronary artery bypass grafting has previously been shown to improve left ventricular function, we believe this is the first report of improved right ventricular function after coronary revascularization.

Aneurysmal bone cyst of the rib: a review and report of two cases

Aneurysmal bone cyst (ABC) is a benign lesion and generally occurs in the long bones and vertebral column. ABC of the rib is an uncommon entity. Two cases of ABC involving the rib are reported. Its occurrence in the eight decade of life as manifested in one of our patients is extremely rare. The aetiology, clinical manifestations, pathology and treatment are briefly discussed. En bloc resection of the lesion is curative, and offers a good cosmetic and functional result.

Self-inflicted hand injuries: diagnostic challenge and treatment

Self-inflicted injuries are probably more common than is generally appreciated. Three patients with self-inflicted hand injuries are described. A delay in making the correct diagnosis resulted in severe hand disability in 2 of the patients. Early diagnosis of this entity, combined with prompt psychotherapy, prevented disability in the third. The pertinent literature is reviewed and the importance of early diagnosis and psychotherapy is stressed.

The Longitudinal Interval Follow-up Evaluation. A comprehensive method for assessing outcome in prospective longitudinal studies

The Longitudinal Interval Follow-up Evaluation (LIFE) is an integrated system for assessing the longitudinal course of psychiatric disorders. It consists of a semistructured interview, an Instruction booklet, a coding sheet, and a set of training materials. An interviewer uses the LIFE to collect detailed psychosocial, psychopathologic, and treatment information for a six-month follow-up interval. The weekly psychopathology measures ("psychiatric status ratings") are ordinal symptom-based scales with categories defined to match the levels of symptoms used in the Research Diagnostic Criteria. The ratings provide a separate, concurrent record of the course of each disorder initially diagnosed in patients or developing during the follow-up. Any DSM-III or Research Diagnostic Criteria disorder can be rated with the LIFE, and any length or number of follow-up intervals can be accommodated. The psychosocial and treatment information is recorded so that these data can be linked temporally to the psychiatric status ratings.

Factitious lymphedema of the hand: a diagnostic challenge

A case of factitious lymphedema of the hand is presented. Attention is drawn to this entity and its differential diagnosis. Delayed detection in our case resulted in prolonged and costly hospitalization with some loss of hand function. Treatment should be left to those skilled in psychotherapy.

Intrathoracic abnormalities demonstrated by technetium-99m sulfur colloid imaging

Since the scintillation camera enables us to include lower thorax in the views obtained during Tc-99m colloid imaging of the liver and spleen, intrathoracic pathology may be identified as relatively cold or hot areas in the thoracic cavity. Eighteen patients who underwent Tc-99m sulfur colloid imaging during a one-year period were found to have intrathoracic pathology demonstrated either as photopenic areas or as areas of increased radioactivity. These patients' clinical data and the results of other diagnostic modalities, including autopsy, were correlated with the Tc-99m images. The intrathoracic disease processes recognized were bacteremia, two cases; pleural effusion, two cases; lung pathology, one case; and cardiomegaly, 13 cases. With the Exception of two patients with bacteremia who had substantial radiocolloid sequestration by the lung, all the other patients had hepatic dysfunction. The presence of compromised hepatic function allows the visualization of intrathoracic abnormalities: photopenia suggesting pleural fluid collection or an enlarged cardiac silhouette (either photopenia or increased radioactivity occupying a large space in the anterior view to yield cardiothoracic ratio of greater than 50%). Therefore, Tc-99m sulfur during colloid liver-spleen imaging, patients with hepatic dysfunction may incidentally demonstrate intrathoracic pathology, especially cardiomegaly.