The metabolic effects of intermittent versus continuous feeding in critically ill patients

Intermittent (or bolus) feeding regimens in critically ill patients have been of increasing interest to clinicians and scientists. Changes in amino acid, fat and carbohydrate metabolites over time might yet deliver other benefits (e.g. modulation of the circadian rhythm and sleep, and impacts on ghrelin secretion, insulin resistance and autophagy). We set out to characterise these changes in metabolite concentration. The Intermittent versus Continuous Feeding in Critically Ill paitents study (NCT02358512) was an eight-centre single-blinded randomised controlled trial. Patients were randomised to received a continuous (control arm) or intermittent (6x/day, intervention arm) enteral feeding regimen. Blood samples were taken on trial days 1, 7 and 10 immediately before and 30 min after intermittent feeds, and at equivalent timepoints in the control arm. A pre-planned targeted metabolomic analysis was performend using Nuclear Resonance Spectroscopy. Five hundred and ninety four samples were analysed from 75 patients. A total of 24 amino acid-, 19 lipid based-, and 44 small molecule metabolite features. Across the main two axes of variation (40-60% and 6-8% of variance), no broad patterns distinguished between intermittent or continuous feeding arms, across intra-day sampling times or over the 10 days from initial ICU admission. Logfold decreases in abundance were seen in metabolites related to amino acids (Glutamine - 0.682; Alanine - 0.594), ketone body metabolism (Acetone - 0.64; 3-Hydroxybutyric Acid - 0.632; Acetonacetic Acid - 0.586), fatty acid (carnitine - 0.509) and carbohydrate metabolism ( Maltose - 0.510; Citric Acid - 0.485). 2-3 Butanediol, a by-product of sugar-fermenting microbial metabolism also decreased (- 0.489). No correlation was seen with change in quadriceps muscle mass for any of the 20 metabolites varying with time (all p > 0.05). Increasing severity of organ failure was related to increasing ketone body metabolism (3 Hydroxybutyric Acid-1 and - 3; p = 0.056 and p = 0.014), carnitine deficiency (p = 0.002) and alanine abundancy (p - 0.005). A 6-times a day intermittent feeding regimen did not alter metabolite patterns across time compared to continuous feeding in critically ill patients, either within a 24 h period or across 10 days of intervention. Future research on intermittent feeding regimens should focus on clinical process benefits, or extended gut rest and fasting.

TB treatment delay associated with drug resistance and admission at Daru General Hospital in Papua New Guinea

SETTING

Daru General Hospital, Daru Island, Papua New Guinea, where high rates of tuberculosis (TB) have been reported. Prompt diagnosis and effective treatment are needed for improving TB outcomes and to prevent nosocomial transmission.

OBJECTIVE

To assess the time to treatment initiation and the risk factors associated with delayed treatment for patients started on TB treatment at Daru General Hospital from January to September 2017.

DESIGN

This was a retrospective cohort study that entailed reviewing the records from treatment, admission, discharge and presumptive TB registers.

RESULTS

The study included 360 patients on TB treatment. The median time from presentation to treatment initiation was 7 days [IQR 3-11]. Treatment was started <7 days for 215 patients (60%); however, only 16.2% commenced treatment <2 days. Risk factors for delayed treatment were diagnosis of TB as an inpatient (OR 2.67, 95% CI 1.35-5.28, P = 0.005) and having drug-resistant TB (OR 2.65, 95% CI 1.5-4.68. P = 0.001).

CONCLUSION

A high proportion of TB patients commenced treatment <7 days. Inpatient status, DR-TB and lack of microbiological confirmation were associated with delays in treatment initiation. We recommend that programmes monitor the time from presentation to treatment initiation, and propose that a period of >3 days from presentation to treatment initiation be considered as delayed treatment initiation.

Parents' use of harsh punishment and young children's behaviour and achievement: a longitudinal study of Jamaican children with conduct problems

INTRODUCTION

Harsh punishment by parents is common in low- and middle-income countries (LMIC), yet there is limited evidence from LMIC of the effects of harsh punishment on child outcomes.

METHODS

A longitudinal, prospective study was conducted with children with conduct problems to examine the associations between parents' use of harsh punishment during the preschool years on child behaviour and school achievement in grade one of primary school. As part of an efficacy trial in 24 preschools, 225 children with the highest level of teacher-reported conduct problems were evaluated and their parents reported on how often they used harsh punishment. Outcome measures in grade one included child conduct problems by independent observation, teacher and parent report, child social skills by teacher and parent report, direct tests of children's academic achievement and language skills, and tester ratings of child attention and impulse control.

RESULTS

Children had a mean age of 6.92 years and 61% were boys. All parents reported using harsh punishment. After controlling for child age and sex, socio-economic status, parents' involvement with child and maternal education, frequency of harsh punishment was associated with growth in child conduct problems by independent classroom observations (p  =  0.037), parent (p  =  0.018) and teacher (p  =  0.044) report, a reduction in child social skills by teacher (p  =  0.024) and parent (p  =  0.014) report and poorer attention during the test session (p  =  0.049).

CONCLUSION

The associations between frequency of parents' use of harsh punishment with their preschoolers with conduct problems and later child behaviour indicate a need to train parents in non-violent behaviour management.

The Ex-Vivo-Shunt-Model: Novel Approach for Assessing the Thrombogenicity of Vascular Implants

OBJECTIVE

Disadvantages associated with commercially available vascular implants necessitate alternative strategies to develop new vascular prostheses. Although many tissue characterizing strategies have been defined, no valid test for thrombogenicity exists. Here we introduce a novel concept for thrombogenicity testing of vascular implants

METHODS

Silastic tubes were implanted into the carotid arteries of 12 sheep. After placing these shunts, tc99m-labeled platelets were administered and test-vessels were put in between the shunts. Native autologous (n=6), as well as native/acellularized allogeneic (n=6/n=6), and xenogeneic (n=6/n=6) carotid arteries and allogeneic (n=6/n=6) and xenogeneic (n=6/n=6) carotid arteries reseeded with allogeneic endothelial-cells, fibroblasts and myocytes were evaluated. Number and time course of intra-operatively deposited platelets were evaluated with a Geiger-counter; certain areas of platelet deposition located, envisioned and characterized by a gamma-camera and scanning electron-microscopy afterwards.

RESULTS

Counter results revealed no significant different platelet depositions when comparing silastic tubes with either autologous or allogeneic native carotid arteries. However, starting 5 minutes after placement, acellularized/reseeded allogeneic (p=0.001/p=0.00004), and xenogeneic (p=0.0001/p=0.01) carotid arteries showed significantly more platelet depositions than native autologous carotides. Moreover, it was possible to show that almost no platelets adhere to native vessels or silastic tubes, thus proving the test method itself.

CONCLUSION

The Ex-Vivo-Shunt-Model is a valid method to measure and envision the intrinsic thrombogenicity of vascular implants.

Radiofrequency-induced intradiscal nucleoplasty chronic low back pain secondary to lumbar disc herniation

We set out to assess the efficacy of radiofrequency-induced intradiscal nucleoplasty in reducing pain in symptomatic patients with MRI-defined lumbar disc herniation and their satisfaction with the procedure. We compared the patients’ pain intensity and severity of disability scores before and after undergoing the procedure in a retrospective questionnaire. These patients reported statistically significant reduction of pain intensity and disability level after the procedure. We conclude that radiofrequencyinduced intradiscal nucleoplasty is an acceptable alternative minimally invasive procedure in relieving the symptoms of patients with lumbar disc herniation.

A STUDY OF THE NEUROTROPIC TENDENCY IN STRAINS OF THE VIRUS OF EPIDEMIC INFLUENZA

The demonstration by Stuart-Harris that the W.S. strain of epidemic influenza virus can induce a fatal nervous disease in mice has been confirmed. In contrast, however, no previous period of adaptation to chick embryonic brain was required. By serial brain to brain passages in mice originally inoculated with the virus cultivated in the usual chick embryo culture medium a fatal disease, essentially meningeal in character, is produced. The Melbourne strain has been similarly enhanced while other strains have failed to reveal any neurotropic tendencies. The evidence indicates that the neurotropic characteristic is present in the two strains as an inherent quality which is quantitatively heightened and does not represent the acquisition of a property not previously present.

CUTANEOUS REACTIONS TO THE POLYSACCHARIDES AND PROTEINS OF PNEUMOCOCCUS IN LOBAR PNEUMONIA

I. a. Pneumococcus polysaccharides, when injected intradermally into patients convalescent from pneumonia, are capable of eliciting a response. The polysaccharide inducing a cutaneous reaction was found always to be homologous in type to that of the pneumococcus causing the infection. b. The character of the reaction incited by the protein-free bacterial sugars is of the immediate wheal and erythema type. c. A patient's capacity to react was found to be intimately associated both with recovery from infection and with the presence of type specific antibodies in the circulating blood. II. a. The so-called nucleo-protein of pneumococcus, when injected intradermally, also causes a local cutaneous reaction in patients during convalescence from lobar pneumonia. b. The local lesion resulting from the injection of protein is tuberculin-like in character, and differs from that evoked by the type-specific polysaccharides in gross appearance, time of development, and duration. c. Individuals, acutely ill with and convalescent from pneumococcus pneumonia, possess in their circulating blood, precipitins reactive with pneumococcus protein. In the observations recorded, the concentration of anti-protein antibodies in the blood serum did not seem to influence the patient's capacity to react to intradermal injection of the protein.

STUDIES WITH HUMAN INFLUENZA VIRUS CULTIVATED IN ARTIFICIAL MEDIUM

The in vitro cultivation of strains of human influenza virus has been successfully conducted through a prolonged series of successive transfers. The cultivated virus has retained the antigenic and immunological properties which characterized the animal passage virus from which it was derived. The culture virus is still virulent for mice and ferrets; it is capable of inducing an active state of immunity in animals vaccinated subcutaneously or intraperitoneally; it elicits specific neutralizing antibodies in the serum of infected or vaccinated animals. The virus has been successfully cultivated to date only in the presence of oxygen; when conditions of reduced oxygenation are imposed by the use of vaseline seal, with or without the addition of cystein, multiplication of the virus is not supported. On the other hand, it has been possible to cultivate the virus in the medium of Li and Rivers in ordinary test tubes. This affords a greatly simplified procedure, since the interval between transfers may be prolonged. The results of neutralization tests with various sera and the culture virus are presented and discussed.

SEROLOGICAL REACTIONS IN PNEUMONIA WITH A NON-PROTEIN SOMATIC FRACTION OF PNEUMOCOCCUS

1. Sera from individuals acutely ill with lobar pneumonia possess the capacity to precipitate in high titre a non-protein somatic fraction derived from pneumococci (Fraction C). Following crisis the reaction is no longer demonstrable. 2. Sera obtained from cases of pneumococcus pneumonia during illness and convalescence have been tested for antibodies specifically reactive with three chemically distinct constituents of Pneumococcus. The results, when correlated with the course of disease, demonstrate differences in the occurrence of each qualitatively distinct antibody. 3. The precipitation of pneumococcus Fraction C is not limited to the sera of individuals ill with pneumococcus infection. But in the few other cases available for comparative tests, definite reactions have been obtained only in streptococcus and staphylococcus infections and in acute rheumatic fever.

STUDIES ON THE NASAL HISTOLOGY OF EPIDEMIC INFLUENZA VIRUS INFECTION IN THE FERRET : II. THE RESISTANCE OF REGENERATING RESPIRATORY EPITHELIUM TO REINFECTION AND TO PHYSICOCHEMICAL INJURY

Because of the marked morphological abnormality of the nasal respiratory epithelium in ferrets recovering from epidemic influenza virus infection, attempts were made to determine whether the anatomical changes were associated with functional changes in the epithelial cells. It was found that on the 7th or 8th day after infection, at which time an immature transitional type of epithelium covers the respiratory area, the cells are resistant not only to reinfection with influenza virus but to a severe physicochemical stimulus supplied by iontophoresis or prolonged irrigation with zinc sulfate. Later, as the ciliated columnar cells return, susceptibility to physicochemical injury returns although resistance to influenza virus persists. The ciliated columnar cells are the ones which are damaged by the physicochemical agent while the deeper cells in the regenerating area remain unaffected. 5 weeks after infection the epithelium is anatomically normal but tissue resistance to zinc sulfate is still present to some degree as evidenced by foci of undamaged cells remaining after ionization. The olfactory epithelium which is undamaged by the PR8 strain of epidemic influenza virus also becomes resistant to ionization after infection. As soon as the respiratory epithelium exhibits any loss of resistance to zinc sulfate the chemical produces complete necrosis of the olfactory area. The refractory state to physicochemical agents exhibited by the regenerating nasal mucosa of the ferret after influenza virus infection is thought to be a non-specific resistant state, significant for a time at least, in the mechanism of immunity to influenza virus.

THE VALUE OF THE SKIN TEST WITH TYPE-SPECIFIC CAPSULAR POLYSACCHARIDE IN THE SERUM TREATMENT OF TYPE I PNEUMOCOCCUS PNEUMONIA

Skin tests were made with Type I S.S.S. in 53 cases of Type I pneumococcus lobar pneumonia, 48 of which were treated with antipneumococcus Type I serum. In all but 1 of the 46 recovered cases a positive, immediate skin reaction was obtained at about the time of recovery. In 7 fatal cases reactions were consistently negative, even in the presence of circulating type-specific antibodies. The skin test has proved to be an extremely valuable guide to serum therapy, and a definite prognostic aid. The test has distinct advantages over the agglutination reaction in that it is not merely an index of circulating antibodies. When positive, it invariably denotes that recovery has begun; when negative, it indicates further serum therapy. The mechanism of the positive skin test is closely related to that operative in recovery from pneumonia, and is apparently the resultant of antibody and tissue activity.

EXPERIMENTAL TYPE III PNEUMOCOCCUS PNEUMONIA IN MONKEYS : II. TREATMENT WITH AN ENZYME WHICH DECOMPOSES THE SPECIFIC CAPSULAR POLYSACCHARIDE OF PNEUMOCOCCUS TYPE III

The effects of specific enzyme therapy upon experimental Type III pneumococcus pneumonia in monkeys were studied by comparing the course and outcome of the disease in treated animals with that in animals which received no therapeutic aid. Enzyme treatment was found to exert a distinctly favorable influence upon the experimental pneumonia. Treatment was followed by cessation of spread of the pneumonic lesion, sterilization of the blood, and early recovery, except in animals in which the severity of the disease was extreme. While in the untreated animals a high incidence of empyema and pericarditis was observed, suppurative sequelae were apparently prevented by adequate enzyme therapy. The limitations of the therapeutic action of the specific enzyme in the presence of marked depression of the cellular reaction in infected animals are again emphasized.

NEUTRALIZATION TESTS WITH SERA OF CONVALESCENT OR IMMUNIZED ANIMALS AND THE VIRUSES OF SWINE AND HUMAN INFLUENZA

Human and swine influenza viruses were regularly neutralized by their homologous immune sera. However, the sera of animals convalescent from infection with either the swine or human influenza virus possessed little, if any, neutralizing capacity for the heterologous virus. Hyperimmunization of animals against swine influenza virus tended to increase the neutralizing capacity of their sera for human influenza virus, but in an inconstant fashion, whereas repeated inoculations with human influenza virus frequently resulted in sera with strong neutralizing activities against swine influenza virus. These observations serve to emphasize both the immunological distinctiveness and the interrelationships of swine and human influenza viruses.

THE SUSCEPTIBILITY OF SWINE TO THE VIRUS OF HUMAN INFLUENZA

Swine inoculated intranasally with human influenza virus alone develop an ill defined, mild, and usually afebrile illness of short duration. At postmortem the anterior lobes of the lungs of such animals contain scant, scattered areas of lobular atelectasis. Transmission of the virus for 5 serial passages through two groups of swine failed noticeably to enhance its pathogenicity for this species. The disease produced in swine by infection with human influenza virus alone is indistinguishable clinically and pathologically from that caused by infection with swine influenza virus alone. Transmission of human influenza virus from swine to swine by contact succeeded in only one of four attempts. Swine inoculated intranasally with a mixture of human influenza virus and H. influenzae suis usually develop a febrile, depressing illness similar to mild swine influenza. The pneumonia encountered in such animals at autopsy is similar to but less extensive than that seen in swine influenza. In some animals H. influenzae suis fails to become established and the disease then seen is identical with that caused by human influenza virus alone. The human influenza virus recovered after 5 serial transfers in swine was immunologically the same as that with which the experiments were begun.

CUTANEOUS REACTIONS IN PNEUMONIA. THE DEVELOPMENT OF ANTIBODIES FOLLOWING THE INTRADERMAL INJECTION OF TYPE-SPECIFIC POLYSACCHARIDE

The majority of patients convalescent from pneumonia due to Types I, II and III Pneumococcus develop at the time of recovery circulating antibodies for the homologous type of organisms. At the same time an immediate wheal and erythema reaction followed the intradermal injection of the homologous type-specific polysaccharide in 100 per cent of Type I patients, 58.8 per cent of Type II patients, and 44 per cent of Type III patients. In a group of 18 patients repeatedly tested with the type-specific polysaccharides, 10 developed in the second or third week of convalescence circulating antibodies for one or more heterologous types. In none of 21 control patients was this phenomenon observed. It is suggested that the development of circulating antibodies for heterologous types of Pneumococcus was associated with the previous intradermal injections of the type-specific polysaccharides.

EXPERIMENTAL TYPE III PNEUMOCOCCUS PNEUMONIA IN MONKEYS : I. PRODUCTION AND CLINICAL COURSE

It has been possible by the intratracheal or intrabronchial inoculation of Type III Pneumococcus to produce in monkeys of the M. cynomolgos species an experimental pneumonia which in its clinical aspects closely resembles pneumococcus lobar pneumonia in man. The experimental disease is characterized by the development of a well localized pulmonary lesion of lobar distribution which tends to spread, the frequent occurrence of septicemia, a sustained fever, and the termination of the infection after a variable interval, in recovery or death of the animal. Wide variations in the severity of the disease in different monkeys have been noted. These variations appear to be due primarily to differences in the resistance of individual animals. The height of the septicemia accompanying the experimental pneumonia has been found to be the most valuable objective index of the probable outcome of the disease. Other factors which may influence the course and outcome of the disease are discussed.

CUTANEOUS REACTIONS IN RABBITS TO THE TYPE-SPECIFIC CAPSULAR POLYSACCHARIDES OF PNEUMOCOCCUS

The injection of the type-specific capsular polysaccharides of Pneumococcus Types I, II and III into the skin of rabbits, actively or passively immunized to one of these types of Pneumococcus, elicits a type-specific cutaneous reaction. The form of reaction resembles that described by Arthus. The reaction is produced only when type-specific precipitins for the homologous polysaccharide are demonstrable in the blood of the rabbit. In 84 per cent of actively immunized rabbits, the serum of which contained type-specific precipitins, a reaction was elicited. A positive result was obtained in 100 per cent of rabbits passively immunized with antipneumococcus horse serum whereas, attempts passively to transfer reactivity from immune rabbit to normal rabbit were unsuccessful. The recipients, in the latter group, possessed no demonstrable circulating type-specific precipitins. The reaction produced by specific capsular carbohydrates is always associated with a well grounded type-specific immunity. A brief summary of the relation of hypersensitiveness and immunity to pneumococcus is given.

THE INACTIVATION OF THE VIRUS OF LYMPHOCYTIC CHORIOMENINGITIS BY SOAPS

The capacities of certain compounds at pH 7.3–7.5 to inactivate the virus of lymphocytic choriomeningitis have been demonstrated. Among the more effective substances were the fatty acids chaulmoogric, linolic, linolenic, myristic, oleic, and ricinolic, and the detergents zephiran, duponol LS, and aerosol OT. Upon the oleic acid inactivation of the virus, studies have been made of such variables as pH, rate of inactivation, and relative amounts of virus and oleate for removal of the infectivity. The rôle of oxidation in the process was determined as negligible. Attempts to recover infectious virus from oleate-inactivated mixtures have been unsuccessful. It has been found that neither oleate nor ether-inactivated virus was capable of producing immunity in mice under the experimental conditions in which untreated virus induced a moderate immunity.

STUDIES ON THE NASAL HISTOLOGY OF EPIDEMIC INFLUENZA VIRUS INFECTION IN THE FERRET : I. THE DEVELOPMENT AND REPAIR OF THE NASAL LESION

A study has been made of the nasal histology in normal ferrets and in ferrets during and after infection with epidemic influenza virus. During the acute stage of infection the respiratory epithelium of the nasal mucous membrane undergoes necrosis with desquamation of the superficial cells and exudation into the air passages, and an inflammatory reaction occurs in the submucosa. Repair begins on the 4th day after infection, and from the 6th to the 14th day the respiratory area is covered successively by a transitional, a stratified squamous, and finally a stratified columnar epithelium. By the 21st day after infection the epithelium has been largely restored to normal but repair in the submucosa and cartilage is still in progress. The respiratory mucosa is substantially normal in structure 1 month after infection although minor abnormalities of cellular arrangement and type can still be distinguished.

RIFT VALLEY FEVER : A REPORT OF THREE CASES OF LABORATORY INFECTION AND THE EXPERIMENTAL TRANSMISSION OF THE DISEASE TO FERRETS

Three cases of Rift Valley fever in human individuals are reported. The virus was recovered from the respiratory tract of the patients and was transmitted to ferrets by the intranasal route. The experimental disease so produced in ferrets is characterized by fever, marked pulmonary lesions, and hemorrhagic phenomena. The results indicate that the virus of Rift Valley fever belongs to the group of filterable viruses which may gain entrance to the human body through the respiratory tract. The differential diagnosis of Rift Valley fever and influenza is discussed. While, clinically, this is a difficult problem, the diagnosis may be readily established through animal experimentation. Certain observations concerning the influence of the route of administration on the protective action of immune serum in serum-virus mixtures are presented.

THE ANTIGENIC POTENCY OF EPIDEMIC INFLUENZA VIRUS FOLLOWING INACTIVATION BY ULTRAVIOLET RADIATION

A study of the antigenic potency of influenza virus inactivated by ultraviolet radiation has been made. Virus so inactivated is still capable of functioning as an immunizing agent when given to mice by the intraperitoneal route. In high concentrations inactivated virus appears to be nearly as effective as active virus but when quantitative comparisons of the immunity induced by different dilutions are made, it is seen that a hundredfold loss in immunizing capacity occurs during inactivation. Virus in suspensions prepared from the lungs of infected mice is inactivated more rapidly than virus in tissue culture medium. A standard for the comparison of vaccines of epidemic influenza virus is proposed.

STUDIES ON THE NASAL HISTOLOGY OF EPIDEMIC INFLUENZA VIRUS INFECTION IN THE FERRET : III. HISTOLOGICAL AND SEROLOGICAL OBSERVATIONS ON FERRETS RECEIVING REPEATED INOCULATIONS OF EPIDEMIC INFUENZA VIRUS

A study of the respiratory mucous membrane was made in the turbinates of ferrets which had received repeated inoculations of influenza virus. There was no evidence that persistent immunity is related to the presence of a structural modification of the respiratory epithelium. In fact, the respiratory epithelium in fully immune animals differs histologically only in minor respects from that of the normal, untreated ferret. On the other hand, a functional difference exists between the normal and the previously infected animals as evidenced by a marked acceleration of the repair process in the latter. Serological studies at the time of reinfection, 4 months or more after the previous attack, indicate that a relation exists between the height of antibody titer and resistance. The degree of immunity is probably a product of serological immunity and the rate of tissue repair. The implications of these studies to the problem of influenza in man are discussed.

THE INCIDENCE OF NEUTRALIZING ANTIBODIES FOR HUMAN INFLUENZA VIRUS IN THE SERUM OF HUMAN INDIVIDUALS OF DIFFERENT AGES

The results of mouse protection tests with 136 human sera and a strain of human influenza virus are described. After the 1st year of life, the sera of approximately half the individuals tested contained sufficient antibody to furnish complete protection to mice. A much higher percentage of the sera obtained from individuals recently convalescent from influenza exerted a completely protective effect. On the other hand, certain sera protected only partially under the conditions of the tests. The results have been compared with those obtained by Shope in tests done with the same sera against swine influenza virus. The possible epidemiological significance of the results is discussed.

THE INACTIVATION OF THE VIRUS OF EPIDEMIC INFLUENZA BY SOAPS

The capacity of certain fatty acids at pH 7.5 to inactivate the virus of epidemic influenza has been demonstrated. Most effective of these are oleic, linolic, and linolenic acids. Studies were made of such variables as pH, rate of inactivation, and ratios of reactant concentrations, using oleic acid as a prototype of the effective acids. Attempts to recover active virus from inactive mixtures by decrease in pH, dialysis, dilution, or addition of calcium chloride solution to inactivated virus have been unsuccessful. The stability of virus at different hydrogen ion concentrations has been determined. Quantitative comparisons have been made of the immunizing capacity of fully active virus and virus rendered non-infectious by treatment with oleic acid. It was found that while the infectious property of the virus is removed the immunogenic capacity is essentially unaltered. The possible mechanism by which the soaps act upon influenza virus has been discussed.

THE ACTION OF IMMUNE SERUM ON HUMAN INFLUENZA VIRUS IN VITRO

Studies have been conducted on the effect of immune serum upon a strain of human influenza virus (PR8) grown in chick embryo tissue culture medium. The results have demonstrated (a) that when cells are exposed to the action of immune serum of high titer and subsequently washed freely, these cells support the growth of virus as well as cells treated with normal serum; (b) that, in agreement with the results of other workers, when virus is added to cell suspensions before the addition of immune serum of low titer, virus survives in the cells; (c) that when mixtures of immune serum of low titer and virus are added to cells, there is little evidence of survival or multiplication of the virus. Furthermore, when immune serum of high titer is used the virus is inactivated regardless of whether the cells are first exposed to virus or immune serum. Finally, virus mixed with a strong immune serum is inactivated in the absence of cells, as shown by the fact that centrifugation at high speeds of such serum-virus mixtures yields no active virus, whereas normal serum-virus mixtures yield fully active virus.

IMMUNOLOGICAL STUDIES WITH THE VIRUS OF INFLUENZA

Following infection with the virus of influenza, both ferrets and mice develop a state of active immunity to reinfection. The serum of these animals contains neutralizing antibodies, as evidenced by the capacity of the serum to confer passive protection to mice against infection with the P.R.8 and Phila. strains of the virus of human influenza. Rabbits which are apparently insusceptible to infection with the virus of influenza produce specific antibodies in response to repeated injection of virus-containing material. The serum of immunized rabbits affords passive protection to mice against mouse-virulent virus. Although the subcutaneous or intraperitoneal injection of the living virus does not produce infection in mice, animals so treated acquire active immunity against subsequent infection by the intranasal route. Neutralization tests with the serum of patients before and after recovery from influenza, pneumonia and the common cold indicate that neutralizing antibodies arise as a specific response to infection with the virus of influenza. The immunological identity of strains of influenza virus recovered from human sources has been established, and the possible existence of strains of related, but not identical, antigenic structure is discussed.

THE DEMONSTRATION OF LESIONS AND VIRUS IN THE LUNGS OF MICE RECEIVING LARGE INTRA-PERITONEAL INOCULATIONS OF EPIDEMIC INFLUENZA VIRUS

Following the intraperitoneal inoculation of mice with large doses of epidemic influenza virus (50,000 to 1 million intranasal M.L.D.) it can be recovered from the lungs in high concentration, and pulmonary lesions of moderate extent may be observed. The virus reaches its highest titer in the lungs 48 to 72 hours after intraperitoneal injection and may persist for 10 days. Virus may be recovered from the blood in the first 24 hours, but is readily detected in the omentum and peritoneum for 5 to 6 days. Mice which as a result of the intraperitoneal injection of virus show a high concentration of virus in the lungs do not die but become solidly immune to intranasal infection. Moreover, as early as 24 to 48 hours after intraperitoneal inoculation of large amounts of virus the animals may exhibit resistance to infection with fatal doses of virus given intranasally. Influenza virus given intravenously to mice is rapidly removed from the blood but persists in the lungs and induces pulmonary lesions. Virus can also be recovered from the liver for several days. With subcutaneous inoculation of influenza virus, however, the virus does not reach the blood or lungs in detectable amounts although the regional lymph nodes may yield considerable quantities of the agent. A brief consideration is presented of the mechanisms of infection and resistance which may be involved.

THE IDENTITY OF THE MECHANISMS OF TYPE-SPECIFIC AGGLUTININ AND PRECIPITIN REACTIONS WITH PNEUMOCOCCUS

The experimental results which have been described demonstrate the following facts: 1. In the type-specific agglutination reaction, when the organisms are not present in sufficient numbers to absorb completely all the antibodies from the serum, more antibody is bound by cellular S than is required for the process of agglutination. 2. The excess of antibody thus bound can then unite with additional amounts of the specific substance when this is added in soluble form to the agglutinated material. 3. If an excess of the free S is added to an agglutinated mass of antibody and bacteria, the organisms are redispersed and in the suspended state are again specifically agglutinable. 4. When a solution of the specific polysaccharide is added in excess to an homologous immune serum, a prozone is created in which precipitation is inhibited; moreover, if, at this point, type-specific pneumococci are added to the mixture, inhibition of agglutination also occurs. 5. The reactive substance in the type-specific agglutination and precipitation reactions is the same, i.e., the capsular polysaccharide. In the former instance it is combined in the bacterial cell; in the latter, it is in a soluble, chemically purified state and entirely separate from the body of the cell.

STUDIES ON THE SOMATIC C POLYSACCHARIDE OF PNEUMOCOCCUS : I. CUTANEOUS AND SEROLOGICAL REACTIONS IN PNEUMONIA

A study of 46 cases of pneumococcus pneumonia has shown that a characteristic response may be elicited by the intracutaneous injection of 0.1 mg. of the somatic C polysaccharide of pneumococcus. During the acute febrile period in patients who recover, the response consists of a delayed erythema which reaches its maximum intensity in 18 to 24 hours. During convalescence the reaction is not demonstrable. In patients in whom the disease is prolonged by complications the capacity of the skin to react persists. In 7 fatal cases the skin failed to react to C polysaccharide. Parallel studies of the reaction of the patients' serum with C have confirmed and extended the observations of Tillett and Francis on the appearance of the precipitation phenomenon during the acute stages and its disappearance in recovery. That the cutaneous and serological reactions are not specific for pneumococcus infection is shown by the results in 29 control cases. 8 patients with infectious febrile diseases not of pneumococcus origin gave responses similar to those noted in pneumonia. 2 patients with non-infectious fevers and 18 of 19 normal individuals failed to give either skin or serum reactions. These observations emphasize the importance of using separate components of the bacterial cell in the interpretation of cutaneous and serological reactions in pneumonia. The parallelism in results of the skin and serum tests in pneumococcus pneumonia with the somatic carbohydrate C, the significance of the reactions in relation to the clinical course and outcome of the disease, and the frequency of occurrence of both reactions in bacterial infections other than those of pneumococcal origin, are discussed.

DISSOCIATION OF HEMAGGLUTINATING AND ANTIBODY-MEASURING CAPACITIES OF INFLUENZA VIRUS

Preparations of Type B influenza virus, propagated in the embryonated egg and obtained in the form of allantoic fluid, were found after heating at 56 degrees C. for 30 minutes to retain the capacity to agglutinate erythrocytes but no longer measured specific antibody when used as antigen in titrations of serum antibody. The dissociation of the two activities suggests the presence in such virus preparations of a complex virus antigen comprising, (1) a heat-stable component which agglutinates erythrocytes and reacts primarily with specific antibody; (2) a heat-labile component reacting with a factor of normal serum which ordinarily tends to inhibit the hemagglutinating activity of influenza virus. The relation of the reagents to other known serological activities of influenza virus is being studied.

AN UNIDENTIFIED VIRUS PRODUCING ACUTE MENINGITIS AND PNEUMONITIS IN EXPERIMENTAL ANIMALS

An infectious agent is described which belongs apparently to the class of filtrable viruses, but which, on the basis of the evidence at hand, is not to be identified with any virus previously described. The virus has multiple tropisms and is pathogenic for mice, ferrets, and monkeys of both M. rhesus and M. cynomolgos species. Intranasal infection of mice and ferrets causes extensive pneumonic lesions of fatal severity. Intracerebral inoculation of the virus produces in monkeys a lymphocytic choriomeningitis from which the animal recovers, while in mice a rapidly fatal choriomeningitis is produced. Fatal paralysis occurs in a moderate proportion of mice which receive the virus by intraperitoneal or subcutaneous routes, while the remainder become immune to the intracerebral test but not to the intranasal test. Subcutaneous inoculation of mice, monkeys, ferrets, rabbits, and guinea pigs causes local granulomatous induration of the skin with enlargement of the regional lymph nodes. The virus was repeatedly recovered in 1936 from ferrets inoculated with throat washings of patients suffering from an epidemic disease clinically indistinguishable from epidemic influenza. It is impossible, however, to conclude whether the virus is of ferret or human origin. Although possessing many features in common with the virus of lymphocytic choriomeningitis and the virus of lymphogranuloma inguinale, cross immunity tests have failed to yield any evidence that the new agent is immunologically related to either of the aforementioned viruses. For purposes of identification the name virus of acute meningopneumonitis is suggested.

QUANTITATIVE RELATIONSHIPS BETWEEN THE IMMUNIZING DOSE OF EPIDEMIC INFLUENZA VIRUS AND THE RESULTANT IMMUNITY

A direct proportion exists between the concentration of epidemic influenza virus used for intraperitoneal immunization of mice and the degree of immunity to intranasal infection which develops. Mice vaccinated with virus of a given strength resist infection with virus of the same concentration but not more. An irreducible minimum exists since mice vaccinated with less than ten intranasal lethal doses do not develop sufficient immunity to overcome intranasal infection with virus of the same strength. The fact that there exists a limiting threshold for the degree of immunity which a certain strength of virus will induce indicates that the virus does not multiply after intraperitoneal inoculations. In ferrets a state of partial immunity is induced as a result of subcutaneous vaccination with active influenza virus. Vaccination with doses containing 100 or more intranasal infectious units is required for the production of circulating antibodies, protection of the animals from pulmonary involvement, and modification of the severity of the disease. On the other hand, intranasal inoculation with one infectious unit results in a firm, immediate immunity, although the duration of immunity may bear a relation to the severity of the original infection and consequently to the size of the infecting dose. Ferrets in a state of partial immunity resulting from subcutaneous vaccination, or from the waning of a firm immunity following infection, respond to intranasal inoculation of influenza virus with an accelerated production of neutralizing antibodies. The antibody titer under these conditions reaches a much higher level than occurs following a primary infection. Fully immune animals, however, show no further antibody response to a second inoculation.

STUDIES OF THE DISTRIBUTION OF POLIOMYELITIS VIRUS : V. THE VIRUS IN FAMILIAL ASSOCIATES OF CASES

The occurrence and duration of the carrier state in familial associates of recognized cases of poliomyelitis was studied by the examination for virus of stool specimens collected from the members of four families at regular intervals for a period of over 2 months. The results indicate that: (1) virus may persist in their stools continuously for 4 to 5 weeks; (2) virus may be encountered intermittently in the stools; (3) in some instances virus may be present for brief periods only; (4) children are more likely to maintain virus than are adults in the same family; (5) infection of a family takes place rapidly, suggesting again simultaneous infection from a common source.

THE ANTIBODY RESPONSE OF HUMAN SUBJECTS VACCINATED WITH THE VIRUS OF HUMAN INFLUENZA

Human influenza virus cultivated in tissue culture medium may be administered subcutaneously or intradermally to human individuals without causing evidence of infection. Subjects so treated develop a good titer of circulating antibodies effective against mouse passage virus and, if antibodies were previously present, vaccination stimulates the production of more antibody. The antibodies so induced persist for at least 5 months, although in this period of time some decline in titer may have begun. The antibody response to vaccination parallels both in extent and persistence that occurring as a result of the naturally acquired disease. The available data do not enable one to evaluate the effect of vaccination in preventing human infection with influenza. It seems not unlikely that the increase in circulating antibody will be accompanied by an increased ability to combat the natural infection.