Regulation of IFN-γ by IL-13 dictates susceptibility to secondary postinfluenza MRSA pneumonia

Superinfection in mice at day 7 postinfluenza infection exacerbates bacterial pneumonia at least in part via downstream effects of increased IFN-γ signaling. Here we show that up to 3 days postinfluenza infection, mice have reduced susceptibility to superinfection with methicillin-resistant Staphylococcus aureus (MRSA), but that superinfection during that time exacerbated influenza disease. This was due to IL-13 signaling that was advantageous for resolving MRSA infection via inhibition of IFN-γ, but was detrimental to the clearance of influenza virus. However, if superinfection did not occur until the near resolution of influenza infection (day 7), IL-13 signaling was inhibited, at least in part by upregulation of IL-13 decoy receptor (IL-13Rα2), which in turn caused increases in IFN-γ signaling and exacerbation of bacterial infection. Understanding these cytokine sequelae is critical to development of immunotherapies for influenza-MRSA coinfection since perturbations of these sequelae at the wrong time could increase susceptibility to MRSA and/or influenza.

Regulation of IFN-γ by IL-13 dictates the susceptibility to secondary post-influenza MRSA pneumonia (INM3P.439)

Post-IAV superinfections are the primary cause of deaths during IAV pandemics. The superinfection in mice 7 days after IAV infection results in exacerbated bacterial pneumonia mediated by type I and II IFNs. However, the sequelae of cytokine responses early in IAV infection, that eventually determines the later susceptibility is not understood. Here we examined whether the susceptibility to superinfection with MRSA varies during IAV infection. In the first 3 days of IAV infection mice had increased resistance to MRSA superinfection, which required IFNAR and IL-13 signaling to inhibit IFN-γ. IFN-γ-mediated high susceptibility to MRSA pneumonia 7 days after IAV infection was associated with increased IL-13Rα2 production, and was reversible by treatment with mrIL-13 or anti-IL-13Rα2. Thus, early in IAV infection IFNAR signaling maintained IL-13, which increased resistance to MRSA. Then, as IAV infection progressed, the capacity for IL-13 signaling was inhibited, in part by increased IL-13Rα2, resulting in increased IFN-γ levels and susceptibility to MRSA superinfection. Thus, IAV induces a sequence of cytokine responses where early IFNAR-dependent IL-13 signaling suppresses IFN-γ production resulting in enhanced resistance to MRSA challenge. Understanding these cytokine sequelae is critical to development of immunotherapies for IAV-MRSA coinfection since perturbations in the sequence of these events at the wrong time could increase susceptibility to MRSA and/or IAV.

Timing of post-influenza bacterial superinfection with MRSA dictates the outcome of MRSA pneumonia in mice (P4027)

Secondary bacterial pneumonias caused by S. aureus, S. pneumoniae and H. influenzae are a common occurrence following influenza infection and are responsible for significant morbidity and mortality worldwide. Others have shown in murine models that 5-8 days after influenza challenge the susceptibility to secondary bacterial infections increases; though the mechanism of this increased susceptibility is still elusive. Here, we report that 2-3 days after influenza challenge (before the onset of clinical symptoms, i.e. body weight loss) mice actually have increased resistance to secondary infection with methicillin resistant S. aureus (MRSA). Importantly, despite this early protection from MRSA, the response to bacteria early in the influenza infection results in increased viral growth and subsequently death of mice. The mechanism of this increased resistance to secondary MRSA pneumonia early after influenza is dependent on the transient presence of IL-13 and on type I IFN signaling, as mice deficient in these cytokine or cytokine receptor do not show increased resistance to secondary MRSA pneumonia 2-3 days after influenza infection, and injection of exogenous IL-13 to mice co-infected with MRSA pneumonia on day 7 increases resistance to bacteria. Thus, depending on the time of secondary infection in relation to influenza, the disease phenotype contracted by mice is greatly different, awareness of which is important for the design of rational treatments in clinics.

The exposure of the lungs to both fungi and non-replicating virus-like particles, elicits immune imprinting to provide exquisite protection against subsequent influenza virus challenge (P3214)

The pulmonary delivery of both virus-like particles (VLPs) (which bear no antigenic similarities to respiratory pathogens), and the opportunistic fungi, Pneumocystis murina, acted to prime the lungs of mice, thus facilitating heightened and accelerated primary immunity to high-dose influenza challenge. These responses were characterized by accelerated antigen processing by alveolar macrophages (AM’s) and dendritic cells (DC’s) and DC trafficking to the local tracheobronchial lymph node (TBLN). Additionally, CD11c+ cells which had been directly exposed to VLPs were necessary in facilitating the observed enhanced viral clearance. The repopulation of CD11c+ DC’s and AM’s from Ly-6Chi myeloid precursors relied on the expression of CCR2, and in the absence of efficient Ly-6Chi cell trafficking in CCR2 knockout mice, or via antibody depletion, the protection afforded by both Pneumocystis- and VLP-exposure was lost. Thus, immune imprinting in the lung by Pneumocystis infection, or VLP-exposure allowed for accelerated influenza-specific primary immune responses in both the lung and TBLN via Ly-6C- or CCR2-dependent mechanisms, respectively. Importantly, both models resulted in enhanced viral clearance and reduced collateral damage.

Inducible bronchus-associated lymphoid tissue elicited by a protein cage nanoparticle enhances protection in mice against diverse respiratory viruses

BACKGROUND

Destruction of the architectural and subsequently the functional integrity of the lung following pulmonary viral infections is attributable to both the extent of pathogen replication and to the host-generated inflammation associated with the recruitment of immune responses. The presence of antigenically disparate pulmonary viruses and the emergence of novel viruses assures the recurrence of lung damage with infection and resolution of each primary viral infection. Thus, there is a need to develop safe broad spectrum immunoprophylactic strategies capable of enhancing protective immune responses in the lung but which limits immune-mediated lung damage. The immunoprophylactic strategy described here utilizes a protein cage nanoparticle (PCN) to significantly accelerate clearance of diverse respiratory viruses after primary infection and also results in a host immune response that causes less lung damage.

METHODOLOGY/PRINCIPAL FINDINGS

Mice pre-treated with PCN, independent of any specific viral antigens, were protected against both sub-lethal and lethal doses of two different influenza viruses, a mouse-adapted SARS-coronavirus, or mouse pneumovirus. Treatment with PCN significantly increased survival and was marked by enhanced viral clearance, accelerated induction of viral-specific antibody production, and significant decreases in morbidity and lung damage. The enhanced protection appears to be dependent upon the prior development of inducible bronchus-associated lymphoid tissue (iBALT) in the lung in response to the PCN treatment and to be mediated through CD4+ T cell and B cell dependent mechanisms.

CONCLUSIONS/SIGNIFICANCE

The immunoprophylactic strategy described utilizes an infection-independent induction of naturally occurring iBALT prior to infection by a pulmonary viral pathogen. This strategy non-specifically enhances primary immunity to respiratory viruses and is not restricted by the antigen specificities inherent in typical vaccination strategies. PCN treatment is asymptomatic in its application and importantly, ameliorates the damaging inflammation normally associated with the recruitment of immune responses into the lung.

Pulmonary hypertension can be a sequela of prior Pneumocystis pneumonia

Improved treatment regimens have reduced fatalities from opportunistic diseases, such as Pneumocystis pneumonia, in AIDS patients. However, serious chronic conditions, including pulmonary hypertension (PH), are increasing in this group. We report here that when CD4 T cells in Pneumocystis-infected mice are temporally depleted and then allowed to return, the extended inflammation results in PH that persists after Pneumocystis is eliminated. Using this model of PH, we have found that i) the onset of PH is correlated with the return of CD4 T cells, but PH persists after CD4 levels diminish; ii) vascular remodeling accompanies PH, but whereas temporary medial hypertrophy is evident with transient PH in immunocompetent mice, persistent PH is associated with perivascular fibrosis; iii) elevated levels of the fibrotic mediator FIZZ1 are found in bronchoalveolar lavage fluid of mice with persistent PH; and iv) although Th2-related mechanisms may be involved in PH etiology, PH still occurs in interleukin-4 receptor-deficient mice under these conditions. Overall, the data presented here demonstrate that the immune response to an infectious disease pathogen, such as Pneumocystis, can, when perturbed and prolonged, lead to later development of a serious chronic condition such as PH.

Oral vaccination with salmonella simultaneously expressing Yersinia pestis F1 and V antigens protects against bubonic and pneumonic plague

The gut provides a large area for immunization enabling the development of mucosal and systemic Ab responses. To test whether the protective Ags to Yersinia pestis can be orally delivered, the Y. pestis caf1 operon, encoding the F1-Ag and virulence Ag (V-Ag) were cloned into attenuated Salmonella vaccine vectors. F1-Ag expression was controlled under a promoter from the caf1 operon; two different promoters (P), PtetA in pV3, PphoP in pV4, as well as a chimera of the two in pV55 were tested. F1-Ag was amply expressed; the chimera in the pV55 showed the best V-Ag expression. Oral immunization with Salmonella-F1 elicited elevated secretory (S)-IgA and serum IgG titers, and Salmonella-V-Ag(pV55) elicited much greater S-IgA and serum IgG Ab titers than Salmonella-V-Ag(pV3) or Salmonella-V-Ag(pV4). Hence, a new Salmonella vaccine, Salmonella-(F1+V)Ags, made with a single plasmid containing the caf1 operon and the chimeric promoter for V-Ag allowed the simultaneous expression of F1 capsule and V-Ag. Salmonella-(F1+V)Ags elicited elevated Ab titers similar to their monotypic derivatives. For bubonic plague, mice dosed with Salmonella-(F1+V)Ags and Salmonella-F1-Ag showed similar efficacy (>83% survival) against approximately 1000 LD(50) Y. pestis. For pneumonic plague, immunized mice required immunity to both F1- and V-Ags because the mice vaccinated with Salmonella-(F1+V)Ags protected against 100 LD(50) Y. pestis. These results show that a single Salmonella vaccine can deliver both F1- and V-Ags to effect both systemic and mucosal immune protection against Y. pestis.

Role of type I IFNs in pulmonary complications of Pneumocystis murina infection

Despite the advent of highly active antiretroviral therapy, pulmonary complications in AIDS are a common clinical problem. Pneumocystis jiroveci infection causes a life-threatening pneumonia, especially in individuals with CD4 T cell deficiencies as occurs in AIDS. Although Pneumocystis sp. is an extracellular fungal pathogen, CD8 T cells are the predominant lymphocyte recruited to the lung in CD4-deficient humans and mice during Pneumocystis pneumonia, and we have found that these CD8 T cells are responsible for subsequent lung damage in CD4 T cell-depleted mice. Comparing CD4 T cell-depleted IFN-alpha receptor knockout (KO) mice to wild-type mice, we found that this CD8 T cell recruitment and lung damage is type I IFN (IFN-alphabeta) dependent. However, in both CD4 competent, wild-type and IFN-alpha receptor (IFNAR) KO mice, Pneumocystis infection leads to an eosinophilic granulocyte influx with bronchial epithelial changes as seen in asthma. This response is delayed in IFNAR KO mice, as is pathogen clearance. Although the inflammation is transient in wild-type animals and resolves upon Pneumocystis clearance, it is more severe and persists through day 35 postinfection in IFNAR KO mice, leading to fibrosis. In addition, IFNAR KO, but not wild-type, mice mount a Pneumocystis-specific IgE response, an indicator of allergic sensitization. Thus, in the absence of IFNAR signaling and CD4 T cells, Pneumocystis-mediated lung damage does not occur, whereas in CD4-competent animals, the absence of IFNAR signaling results in an exacerbated Th2 response, asthma-like symptoms, and fibrosis. Therefore, both CD4 T cell- and type I IFN-mediated mechanisms can determine pulmonary complications from Pneumocystis infection.

Cyclic ADP-ribose production by CD38 regulates intracellular calcium release, extracellular calcium influx and chemotaxis in neutrophils and is required for bacterial clearance in vivo

Cyclic ADP-ribose is believed to be an important calcium-mobilizing second messenger in invertebrate, mammalian and plant cells. CD38, the best-characterized mammalian ADP-ribosyl cyclase, is postulated to be an important source of cyclic ADP-ribose in vivo. Using CD38-deficient mice, we demonstrate that the loss of CD38 renders mice susceptible to bacterial infections due to an inability of CD38-deficient neutrophils to directionally migrate to the site of infection. Furthermore, we show that cyclic ADP-ribose can directly induce intracellular Ca++ release in neutrophils and is required for sustained extracellular Ca++ influx in neutrophils that have been stimulated by the bacterial chemoattractant, formyl-methionyl-leucyl-phenylalanine (fMLP). Finally, we demonstrate that neutrophil chemotaxis to fMLP is dependent on Ca++ mobilization mediated by cyclic ADP-ribose. Thus, CD38 controls neutrophil chemotaxis to bacterial chemoattractants through its production of cyclic ADP-ribose, and acts as a critical regulator of inflammation and innate immune responses.

Pneumocystis carinii enhances soluble mannose receptor production by macrophages

Phagocytosis of extracellular organisms in the alveolar spaces of the lungs represents the first-line of host defense against pulmonary pathogens. Disruption of this process is likely to interfere with the generation of appropriate specific immune responses, and lead to a delayed or inefficient clearance of the pathogen. Pneumocystis carinii, an opportunistic pathogen in immunodeficient individuals, is cleared from the lung by alveolar macrophages. In the absence of specific anti-Pneumocystis antibodies, phagocytosis is dependent on the non-opsonic macrophage mannose receptor (MR). Recent studies have demonstrated that alveolar macrophage MR activity is downregulated in individuals infected with HIV, and that functional MR is shed from the macrophage cell surface. Here we report that P. carinii enhances the formation of soluble MR by macrophages in vitro. Soluble MR was detected in cell-free alveolar fluid from humans infected with HIV and/or P. carinii, but not in alveolar fluid from healthy controls. Soluble MR was found in association with extracellular clumps of P. carinii in the lungs of mice with P. carinii pneumonia, and was associated with P. carinii organisms purified from these mice. When purified P. carinii organisms were incubated with soluble MR-containing supernatants, they were phagocytosed less readily by alveolar macrophages than were control organisms. Our results suggest that P. carinii organisms enhance the shedding of MR from the surface of alveolar macrophages, and that the resultant soluble MR binds to intra-alveolar organisms, thereby interfering with their non-opsonic uptake via the macrophage cell surface MR.

Induction of fibrinogen expression in the lung epithelium during Pneumocystis carinii pneumonia

Pneumocystis carinii is an important pulmonary pathogen responsible for morbidity and mortality in patients with AIDS. The acute-phase response (APR), the primary mechanism used by the body to restore homeostasis following infection, is characterized by increased levels of circulating fibrinogen (FBG). Although the liver is the primary site of increased FBG synthesis during the APR, we unexpectedly discovered that FBG is synthesized and secreted by lung alveolar epithelial cells in vitro during an inflammatory stimulus. Therefore, we sought to determine whether lung epithelial cells produce FBG in vivo using animal models of P. carinii pneumonia (PCP). Inflammation was noted by an influx of macrophages to P. carinii-infected alveoli. Northern hybridization revealed that gamma-FBG mRNA increased two- to fivefold in P. carinii-infected lung tissue, while RNA in situ hybridization demonstrated increased levels of gamma-FBG mRNA in the lung epithelium. Immunoelectron microscopy detected lung epithelial cell-specific production of FBG, suggesting induction of a localized inflammatory response resembling the APR. A systemic APR was confirmed by a two- to fivefold upregulation of the levels of hepatic gamma-FBG mRNA in animals with PCP, resulting in a corresponding increase in levels of FBG in plasma. Furthermore, immunoelectron microscopy revealed the presence of FBG at the junction of cell membranes of trophic forms of P. carinii organisms aggregated along the alveolar epithelium. These results implicate FBG in the pathogenesis of PCP in a manner similar to that of the adhesive glycoproteins fibronectin and vitronectin, which are known to participate in intra-alveolar aggregation of organisms and adherence of P. carinii to the lung epithelium.

[Tasks of caregivers in a nursing home. A study of tasks and reactions of caregivers]

This paper describes a study on the task perceptions of enrolled nurses in a nursing home and the relationships between task perceptions and reactions such as burnout, job satisfaction, experienced job significance and absenteeism (Harmsen, 1991). In our study a comparison is made on the one hand between the task perceptions of three different functions in the nursing home, namely the unit heads, the graduated and the student nurses, and on the other hand between the task perceptions of enrolled nurses working on two types of wards, namely somatic and psycho-geriatric wards. Concerning the relationships between task perceptions and reactions, the results of our study show that activities regarding the 'nursing record', the 'nursing report', the 'stimulation of self-care' and 'social contact' usually have a positive relationship with the experienced job significance of enrolled nurses. On the contrary, activities concerning daily care are evaluated negative. Finally, tasks in the area of 'instrumental activities', 'caring for the dying' and 'caring for the privacy of the client' appear to have positive as well as negative effects.

Acoustic neuroma surgery: results of translabyrinthine tumour removal in 300 patients. Discussion of choice of approach in relation to overall results and possibility of hearing preservation

The results from the Danish model of acoustic neuroma surgery are presented. In the period from 1976 to 1985, 300 patients with acoustic neuromas were operated upon using the translabyrinthine procedure. Only one small intrameatal tumour was encountered; 96 tumours were medium sized and 203 were larger than 25 mm. Of these 118 measured more than 40 mm. Mortality rate was 2%, CSF leaks occurred in 11%, and had to be closed surgically in 5%. Facial nerve function was postoperatively normal in 66%, slightly reduced in 17%, moderately reduced in 8% and abolished in 9%. Reconstruction, most often as a XII-VII anastomosis, was performed in only 6% of the patients. Cerebellar symptoms, which occurred in 45% preoperatively were present in only 7% after surgery. The preoperative hearing in both the tumour and non-tumour ear was analysed in 72 patients with tumours smaller than 2 cm. In the tumour ear, only four patients had a PTA of 0-20 dB and SDS of 81-100%; eight patients had a PTA of 0-40 dB and SDS of 61-100%; 14 had a PTA of 0-50 dB and SDS of 51-100%. This means that only a maximum of 5% of the patients, using the broadest criteria, could be candidates for hearing-conserving surgery. In all these patients the contralateral ear had hearing within normal limits (PTA 0-20 dB and SDS 95-100%). Since preservation of hearing would be achieved in only half of those subjected to suboccipital removal and since the hearing retained in patients with successful operations generally is poorer than the preoperative level, the number of patients obtaining serviceable hearing is so modest that preservation of hearing cannot be considered a valid argument in favour of suboccipital tumour removal. From a statistical point of view the risk of losing hearing in the opposite ear after tumour removal is negligible. The general morbidity after suboccipital surgery is higher than after translabyrinthine surgery, and hearing loss must be listed low among the other sequelae after tumour removal.

Results of translabyrinthine removal of 300 acoustic neuromas related to tumour size

The results from the Danish model of acoustic neuroma surgery are presented. In the period from 1976 to 1985, 300 patients with acoustic neuromas were operated upon using the translabyrinthine procedure. There were one small intrameatal tumour; 96 medium-sized tumours with an extrameatal diameter up to 25 mm; 85 large tumours, measuring 26-40 mm, and 118 very large tumours with a diameter exceeding 40 mm. The mortality rate was 2%, and CSF leak occurred in 11%, persisting for more than 2 weeks in 5% of the patients in whom the fistula had to be closed operatively. Facial nerve function was completely normal in 66%, slightly reduced in 17%, moderately reduced in 8% and abolished in 9%. The facial nerve was anatomically preserved in 95% of the patients. Reconstruction of the facial nerve, most often an XII-VII anastomosis, was performed in only 6% of the patients. Cerebellar symptoms, occurring in 45% preoperatively, were demonstrated in only 7% postoperatively. We find that a standardization of the measurement of tumor size and of the assessment of sequelae changes is urgently needed.

Is preservation of hearing in acoustic neuroma worthwhile?

In a series of 300 translabyrinthine removals of acoustic neuromas, comprising almost all tumours operated on in Denmark during a period of 10 years, the preoperative hearing in the tumour ear and in the contralateral ear was analysed in 72 patients with tumours smaller than 2 cm in extrameatal diameter. These patients constitute likely candidates for a hearing preserving operation via the suboccipital approach. In the tumour ear in 4 patients there was a pure-tone average (PTA) of 0-20 dB and a discrimination score (DS) of 81-100%. Applying this criterion to the whole series, 1% of the patients would be candidates for a hearing preserving procedure. Changing the criterion to a PTA of 0-40 dB and a DS of 61-100%, the number of candidates would increase to 8 patients (3%), and with a PTA of 0-50 dB and a DS of 51-100% 14 candidates (5%) would have been found. In all of these patients, contralateral hearing was normal (SRT 0-20 dB, DS 95-100%). Since preservation of hearing would be achieved in only half of those subjected to suboccipital removal and since the hearing retained in patients with successful operations is generally poorer than the preoperative level, the number of patients obtaining serviceable hearing is so modest that preservation of hearing cannot be considered an argument in favour of suboccipital tumour removal. It should be borne in mind that contralateral hearing is normal in these patients and that, according to most reports, the mortality rate is higher and paralysis of the facial nerve more frequent with the suboccipital approach than with the translabyrinthine procedure.

Resistance to cerebrospinal fluid outflow and intracranial pressure in patients with hydrocephalus after subarachnoid haemorrhage

Resistance to CSF-outflow (Rout) and intracranial pressure (ICP) were measured in 33 patients with hydrocephalus after subarachnoid haemorrhage (SAH). Eleven patients examined between 10 to 30 days after SAH had high pressure hydrocephalus (HPH). Twenty-two patients had normal pressure hydrocephalus (NPH). All HPH-patients had ICP above 15 mmHg, plateau waves and B-waves, a median Rout of 59 mmHg x ml-1 x min-1 (range 29-100). All NPH-patients had a normal ICP level, no plateau waves, but long periods of B-waves and a median Rout of 22 mmHg x ml-1 x min-1 (range 6-47). Of the 11 patients with HPH six were shunted and five had temporary ventricular drainage. Five patients improved and six died. Of the five survivors only one went back to work. Of the 22 NPH-patients 18 were treated with a shunt, one refused shunt operation and three had normal Rout. Seventeen improved after shunting. At follow-up 12 had a normal social life, 5 lived in a nursing home and 1 was dead. Thus, early development of hydrocephalus after subarachnoid haemorrhage is associated with a high Rout and a high ICP, whereas late (more than one month) hydrocephalus may be associated with normal ICP and high Rout. Patients with NPH and a high Rout have frequent B-waves and should be shunted. Patients with a long interval from subarachnoid haemorrhage to the diagnosis of hydrocephalus often have a normal ICP, low frequency of B-waves, normal CSF-dynamics and need no shunting.

Clinical features and outcome in 1076 patients with ruptured intracranial saccular aneurysms: a prospective consecutive study

In a well-defined area, The Kingdom of Denmark, 1076 patients with ruptured intracranial aneurysms were admitted to the six Danish neurosurgical departments in a prospective consecutive study in the 5-year period 1978-1983. Follow-up examinations were accomplished 3 months and 2 years after the admission. A total of 674 women and 402 men with a median age of 49 years were included in the study. The localisation of the ruptured aneurysms were: internal carotid artery 285, anterior communicating artery and horizontal part of anterior cerebral artery 383, middle cerebral artery 291, basilar and vertebral arteries 83 and peripheral or other localisation 34. A significantly better outcome was seen in cases with internal carotid aneurysms compared to other localisations. 670 patients underwent operation. A highly significantly better outcome was found in operated versus non-operated patients in comparable clinical conditions. The advantage of microneurosurgery was well documented. Patients with vasospasm had a significantly worse outcome. Within the first 2 weeks a daily rebleeding rate from 0.2% to 2.1% was observed, and patients who rebled had a significantly worse outcome compared to patients, who did not rebleed. The overall outcome at 2-year follow-up was: normal 27.5%, mild dementia 15.8%, severe dementia 9.9%, vegetative 1.3% and mortality 45.5%.

Clinical features and outcome in 48 patients with unruptured intracranial saccular aneurysms: a prospective consecutive study

During a 5-year period (1978-1983) the clinical features and operative morbidity/mortality were registered prospectively for all patients in Denmark with an unruptured symptomatic (27 patients) or incidental (21 patients) intracranial saccular aneurysm. A follow-up examination was performed 2 years after diagnosis of the aneurysm. Thirty symptomatic aneurysms in 27 patients most frequently involved the visual pathways or ocular motility (66%). The median diagnostic delay for patients with impaired visual acuity was 7 months but only 14 days for patients with impaired ocular motility. The localisation of the 30 symptomatic and 23 incidental aneurysms were: internal carotid artery (73% approximately 35%), anterior communicating artery (3% approximately 26%) and middle cerebral artery (7% approximately 35%). The diameters of 73% of the symptomatic aneurysms were greater than 10 mm, while the diameter of 74% of the incidental aneurysms were below 10 mm. The total operative morbidity and mortality were 15% and 4%, respectively. The mortality rate in the follow-up period was 10-11% mainly due to fatal bleeding from unoccluded aneurysms. In 21 survivors, a normal mental status was found in 43% and mild dementia was found in another 43%. The impaired visual acuity was unchanged in 67% of patients, while the ocular motility had normalised in 75%. A normal daily functional capacity was enjoyed by 57% while 43% had a moderate reduction, mostly due to visual disturbances.

Severe headache as the only symptom of long-standing shunt dysfunction in hydrocephalic children with normal or slit ventricles revealed by computed tomography

Four patients aged 11, 11, 8 and 18 years, shunted in early childhood for hydrocephalus, were followed in the outpatient clinic for severe headache from 3 months to 2 years. The headache lasted for days and up to a week, was usually severe, and was often followed by screaming attacks or aggressive behavior. In all patients repeated computed tomography disclosed a normal ventricular system or slit ventricles. The intracranial pressure (ICP) was measured in all four patients and showed an increased intracranial steady-state pressure between 20-50 mmHg, plateau waves and, in two of the patients, a very high intracranial pulse-pressure amplitude. At operation all patients had dysfunction of the shunt (most often of the distal end). In three patients ICP monitoring post-operatively showed normal intracranial pressure without any abnormal increments from the normal steady-state pressure. Thus, severe headache can be the only symptom of long-standing shunt dysfunction, even without ventricular dilation. In shunted hydrocephalic children complaining of headaches, ICP measurement is highly recommended.

Serial measurement of regional cerebral blood flow in patients with SAH using 133Xe inhalation and emission computerized tomography

A noninvasive three-dimensional method for measuring cerebral blood flow (CBF), xenon-133 inhalation and emission computerized tomography, was used to investigate the CBF changes accompanying delayed neurological deterioration following subarachnoid hemorrhage (SAH). A total of 67 measurements were performed on 20 patients in Hunt and Hess' clinical Grades I to III in the first 21 days post SAH. Five patients with normal CBF tomograms on admission developed delayed neurological deficits in the 2nd week after hemorrhage, at which time repeat CBF tomograms in four patients revealed large areas of well defined regional flow decrease in the vascular territories of the anterior or middle cerebral arteries. Severe vasospasm was noted in three of these patients in whom arteriography was performed in the 2nd week post SAH. Diffuse bihemispheric CBF decreases were noted later in the course of delayed neurological deficits; however, measurements obtained soon after the onset of focal symptoms suggest that the only CBF decreases directly produced by vasospasm in Grade III patients are regional changes.

Cerebral abscess. A long-term follow-up

During the period 1935-1976, 200 cases of brain abscess were treated in the University Clinic of Neurosurgery, Rigshospitalet, Copenhagen. 119 patients survived. Out of 40 deaths during the follow-up period, 37 were unrelated to the previous brain abscess. 12 patients emigrated and were lost to follow-up. History and neurologic examination of the remaining 67 surviving patients with follow-up periods of between 3 and 40 years (mean 18 years) showed no sequelae in 23, unrestricted working capacity in 46, epilepsy in 37, neurologic deficit in 18, and intellectual impairment in 13 patients. The most serious sequelae, incapacitating epilepsy and severe mental reduction, were seen in patients with brain abscess during childhood.

Controlled hypotension with sodium nitroprusside: effects on cerebral blood flow and cerebral venous blood gases in patients operated for cerebral aneurysms

The effect on cerebral haemodynamics of arterial hypotension induced by sodium nitroprusside infusion was studied in nine patients at the end of operations for intracranial aneurysms under N2O-O2-halothane anaesthesia. Cerebral blood flow (CBF), using the intraarterial 133Xe injection method, and cerebral jugular venous blood gases were monitored before, during and after the induced hypotension. CBF and jugular venous oxygen tension (PvO2) remained constant during the hypotensive period. Following its termination, a 13% increase in CBF occurred (P less than 0.05) and PvO2 showed the same trend, a 5% increase (P less than 0.30). Regional CBF recordings (rCBF) in 16 small areas within the cerebral hemisphere were obtained at each measurement. In four of the patients, rCBF abnormalities were present in the form of hyperaemic regions, probably induced by the operation or the disease itself. The focal abnormalities were not accentuated during hypotension nor were ischaemic regions disclosed. It is concluded that sodium nitroprusside has only a minor influence on cerebral haemodynamics in the anaesthetized state.

Cerebral abscess. Aetiology and pathogenesis, symptoms, diagnosis and treatment. A review of 200 cases from 1935-1976

From 1935-1976 a total of 200 patients with cerebral abscesses were referred to the University Clinic of Neurosurgery, Rigshospitalet, Copenhagen. The primary source of infection could be established in 169 cases (85%). Bacteria could be cultured in 58% of the cases. From 1935-1957 nearly all patients were subjected to ventriculography (107/129). Cerebral angiography was the dominating diagnostic method from 1958-1974. Since then, 30 patients with a suspected intracranial abscess have been examined by computed tomography. The overall mortality has been 40%, but for the period 1958-1976 17%.

X-ray kinetic studies of microtubule assembly using synchrotron radiation

The assembly of microtubules has been investigated by time-resolved X-ray diffraction using synchrotron radiation. The small-angle scattering becomes visible within seconds and thus enables study of the structural transitions of the protein aggregates during assembly from their subunits in solution. The X-ray pattern at 4 degrees C arises from a mixture of tubulin rings, dimers and some other species. Raising the temperature to 36 degrees C induces the breakdown of rings, followed by the growth of microtubules. The results suggest that microtubules may be formed from tubulin oligomers smaller than rings.

Intracranial Saccular Aneurysms. Results of treatment in 851 patients

The series studied comprises all 851 patients with symptom-producing intracranial saccular aneurysms admitted to the departments of neurosurgery in Denmark in the five-year period of 1970-1974. The series was divided into seven clinical stages according to Hunt's classification. More than half of the patients were grouped in stages IV and V (Hunt grade 2-3). Of the patients, 76% were found primarily suitable for operation. The mortality within the individual stages was to a great extent independent of the time of operation. A total of 94% of the aneurysms were localized within the region of the carotid artery, with a roughly equal distribution among the internal carotid, anterior communicating, and middle cerebral arteries. Multiple aneurysms were found in 19% of the patients subjected to panangiography. There was a distinct correlation between the severity of the spasms and the clinical condition. The course of operation was complicated in 49% of the patients, the complications being equally distributed within the various clinical stages. The mortality for the patients who underwent operation (total 567) was 32%, and 80% of the deaths were due to direct or indirect consequences of aneurysmal bleeding. At the follow-up performed two to seven years after operation, 52% of the survivors were fully capacitated, 20% were partly capacitated, and 28% were incapacitated. Based on a retrospective analysis, we have started a comprehensive prospective study with registration of available parameters in patients with saccular aneurysms admitted to all departments of neurosurgery in Denmark.

Intellectual development and brain size in 13 shunted hydrocephalic children

A group of 13 successfully treated hydrocephalic children living a normal social life according to their ages has been examined to evaluate the possible correlation between their brain size, intellectual development and physical disability. The brain size was assesed by ventriculography prior to initial surgery and by computer tomography (CT-scanning) at the time of investigation 6--11 years after operation. The intellectural development was evaluated by psychological investigation of the children and by evaluation of their social adaptation. The physical disability was investigated by neurological examination. Significant improvement in ventricular size was demonstrated from pneumoencephalographic examinations prior to surgery and to the CT investigations. No prediction of the intellectual development could be based on the ventriculographies prior to initial surgery. In spite of positive trends, correlation trends, correlation between the ventricular size as determined by CT-scans and the IQ was not significant, possibly due to the small number of cases available for study.

Incidence and long term survival of children with intracranial tumours treated in Denmark 1935-1959

The total number of children under 15 years of age with intracranial tumours in Denmark during the years 1935-1959 was found to be 533. The average incidence was 21 new cases/10(6) children/year during the 25-year period in question, and 25/10(6) children/year during the first 17 years of Danish cancer registration. The sex ratio (290 boys to 243 girls) was not significantly different from that of the child population in Denmark. In 219 cases the tumour was located in the supratentorial and in 314 in the infratentorial space. 93% of the tumours were histologically verified, with the following order of frequency for the most usual types: astrocytomas (all grades), medulloblastomas, ependymomas, and craniopharyngiomas. Follow-up was 100%. For the 345 children who survived for more than one month after operation or diagnosis, 36% were alive after 15 years. 119 patients were alive in April 1974 and these were all observed between 15-40 years after diagnosis and operation. Of these 44 had tumours in the supratentorial and 75 in the infratentorial space. 66% of the survivors with supratentorial and 90% with infratentorial tumours led a normal life. Most of the survivors had had a cerebellar astrocytoma, a supratentorial astrocytoma, an apendymoma or oligodendroglioma, but other histological diagnoses were also represented, especially in the supratentorial group. The long-term prognosis was especially bad for children with brain-stem tumours, infratentorial ependymomas and medulloblastomas.

Surgery of acoustic neuromas. Preliminary experience with a translabyrinthine approach

Inspired by the works of William House, the authors formed an otoneurosurgical team in order to improve the results after surgery for acoustic neuromas. This paper deals with the preliminary results obtained with the translabyrinthine approach in 13 patients with acoustic neuromas. In 9 patients it was possible to remove the tumor totally with this approach, in 4 patients a second suboccipital operation was necessary to secure total removal. One small, 7 medium and 5 large tumors were encountered. The facial nerve was preserved in 83 per cent of the patients. One patient with a large tumor died after the second suboccipital operation. The relation between size of the tumor and the outcome of the operation is stressed, and in order to reduce the number of large tumors it is suggested that all patients with unilateral hearing loss should be suspected of having a neuroma, until the diagnosis has been disproved. It is concluded that the surgery for acoustic neuromas is otologic-neurosurgical teamwork, and that the treatment should be centralized.

Ultrastructure of muscle biopsies in recent, short-term and long-term juvenile diabetes

Muscle biopsies from juvenile diabetics were studied by electron microscopy and the results correlated to earlier published light microscopical abnormalities of the same biopsies. A total of 32 striated muscle biopsies from 29 juvenile recent, short-term and long-term diabetes were examined. The ages ranged from 16 to 43 years with a diabetes duration from 1 week to 32 years. The material was compared with biopsies from healthy persons of the same ages. The electron microscopy revealed degenerative changes of the striated muscle fibres which signify a neurogenic atrophy. No myopathic alterations were found. The capillaries in both the recent and long-term diabetics showed an extremely pronounced pinocytosis indicating an increased metabolic activity. In the long-term group the intramuscular capillaries both from upper and lower extremities displayed a definitely thickened basement membrane. In the recent and short-term group the capillary wall alterations were debatable. The motor end plate in the recent diabetics revealed minimal alterations. Contrary to this the long-term group showed severe alterations with occasional disappearance of the nerve fibres.