Strategic placement of automated external defibrillators (AEDs) for cardiac arrests in public locations and private residences

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We ranked businesses for their ability to fill gaps in the AED landscape.

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23% of OHCAs in public, and 4% in homes, were within 100 m of an existing AED.

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Many businesses can simultaneously improve coverage of arrests in public and homes.

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Rankings were largely robust to the coverage radius used (100 m, 200 m, and 500 m).

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Even if all 5006 business locations hosted AEDs, large gaps in OHCA coverage remain.

Aim

Methods

Results

Conclusion

Community mental health teams for people with severe mental illnesses and disordered personality

Closure of asylums and institutions for the mentally ill, coupled with government policies focusing on reducing the number of hospital beds for people with severe mental illness in favor of providing care in a variety of nonhospital settings, underpins the rationale behind care in the community. A major thrust toward community care has been the development of community mental health teams.

Induction of autoimmune disease by depletion of regulatory T cells

Organ-specific autoimmune diseases can be induced in rodents that do not normally spontaneously develop autoimmunity by using procedures that render the animals partially T cell deficient. Using a protocol of adult thymectomy followed by four doses of sublethal gamma irradiation, insulin-dependent diabetes can be induced in normal PVG.RT1(u) rats, an inbred congenic strain that has the same major histocompatibility complex (MHC) allotype as the spontaneously diabetic BB rat. Onset of the disease ranges from 3 to 18 weeks after the final dose of irradiation, with 98% of male and 70% of female animals becoming diabetic. This unit describes the induction of insulin-dependent diabetes in the rat. A modified protocol allows for the induction of a more severe form of the disease.

Community mental health teams (CMHTs) for people with severe mental illnesses and disordered personality

BACKGROUND

Closure of asylums and institutions for the mentally ill, coupled with government policies focusing on reducing the number of hospital beds for people with severe mental illness in favour of providing care in a variety of non-hospital settings, underpins the rationale behind care in the community. A major thrust towards community care has been the development of community mental health teams (CMHT).

OBJECTIVES

To evaluate the effects of community mental health team (CMHT) treatment for anyone with serious mental illness compared with standard non-team management.

SEARCH STRATEGY

We searched The Cochrane Schizophrenia Group Trials Register (March 2006). We manually searched the Journal of Personality Disorders, and contacted colleagues at ENMESH, ISSPD and in forensic psychiatry.

SELECTION CRITERIA

We included all randomised controlled trials of CMHT management versus non-team standard care.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis, based on a fixed effects model. We calculated numbers needed to treat/harm (NNT/NNH) where appropriate. For continuous data, we calculated weighted mean differences (WMD) again based on a fixed effects model.

MAIN RESULTS

CMHT management did not reveal any statistically significant difference in death by suicide and in suspicious circumstances (n=587, 3 RCTs, RR 0.49 CI 0.1 to 2.2) although overall, fewer deaths occurred in the CMHT group. We found no significant differences in the number of people leaving the studies early (n=253, 2 RCTs, RR 1.10 CI 0.7 to 1.8). Significantly fewer people in the CMHT group were not satisfied with services compared with those receiving standard care (n=87, RR 0.37 CI 0.2 to 0.8, NNT 4 CI 3 to 11). Also, hospital admission rates were significantly lower in the CMHT group (n=587, 3 RCTs, RR 0.81 CI 0.7 to 1.0, NNT 17 CI 10 to 104) compared with standard care. Admittance to accident and emergency services, contact with primary care, and contact with social services did not reveal any statistical difference between comparison groups.

AUTHORS' CONCLUSIONS

Community mental health team management is not inferior to non-team standard care in any important respects and is superior in promoting greater acceptance of treatment. It may also be superior in reducing hospital admission and avoiding death by suicide. The evidence for CMHT based care is insubstantial considering the massive impact the drive toward community care has on patients, carers, clinicians and the community at large.

Can the frontal assessment battery (FAB) differentiate bradykinetic rigid syndromes? Relation of the FAB to formal neuropsychological testing

The frontal assessment battery (FAB) is a bedside test of executive function. It takes less than 10 minutes to administer and a low score indicates executive dysfunction. To determine whether the FAB could detect the more severe subcortical dementia that is a feature of PSP and differentiate it from other bradykinetic rigid syndromes, we studied 17 patients with progressive supranuclear palsy (PSP); 11 with multiple system atrophy (MSA) and 12 with Parkinson's disease (PD). We compared FAB scores with the results of more detailed tests of executive and general cognitive function.FAB scores were significantly lower in PSP than in MSA or PD (p=0.02 and p<0.001) and were also found to be significantly lower in MSA than in PD (p=0.047). We divided the study group into those with an FAB score <15 and those with an FAB score>/=5, regardless of the clinical diagnosis. While 82% of the PSP group had FAB scores of <15, such scores were recorded in only 36% of the MSA and 8% of the PD groups. The lexical fluency and motor series subscores of the FAB discriminated 70% of the PSP, MSA and PD patients. The FAB scores correlated with tests of executive function, as well as with scores on the Mattis Dementia Rating Scale, the Mini Mental State Examination and other tests of general cognitive function. A stepwise regression analysis revealed that across the groups, among the variables that correlated with FAB scores, alternating semantic fluency accounted for 80% of FAB variance.These results suggest that the FAB is a valid and easily applicable bedside test to discriminate executive dysfunction in these three frequently confused bradykinetic rigid syndromes.

Heavy users of acute psychiatric beds: randomized controlled trial of enhanced community management in an outer London borough

BACKGROUND

Heavy users of psychiatric services, often defined as the population that uses the most beds, consume a large part of the resources used by the whole service, despite being relatively small in number. Any intervention that reduces heavy use is therefore likely to lead to significant savings, and enhancement of standard care using a form of intensive case management akin to assertive community treatment was thought to be a pragmatic strategy for testing in this group.

METHODS

The effectiveness of enhanced community management (ECM) was compared with standard care alone in heavy users, who represented the 10% of patients with the highest number of hospital admissions and occupied bed days over the previous 6.5 years in an outer London borough. One hundred and ninety-three patients were randomly assigned to ECM or standard care and their use of services was determined after 1 and 2 years, with assessments of costs, clinical symptoms, needs, and social function made before entry into the study and after 1 and 2 years.

RESULTS

Despite a 24 fold increase in community contacts in the study group, there were no significant differences between the two groups in any of the main outcome measures. Small savings on in-patient and day-hospital service costs were counterbalanced by the increased costs of outpatient and community care for the subjects assigned to ECM. Clinical outcome data derived from interviews in two-thirds of the subjects were similar in both groups.

CONCLUSIONS

Providing additional intensive community focused care to a group of heavy users of psychiatric in-patient services in an outer London borough does not lead to any important clinical gains or reduced costs of psychiatric care.

Community mental health team management in severe mental illness: a systematic review

BACKGROUND

Community mental health teams are now generally recommended for the management of severe mental illness but a comparative evaluation of their effectiveness is lacking.

AIMS

To assess the benefits of community mental health team management in severe mental illness.

METHOD

A systematic review was conducted of community mental health team management compared with other standard approaches.

RESULTS

Community mental health team management is associated with fewer deaths by suicide and in suspicious circumstances (odds ratio=0.32, 95% Cl 0.09-1.12), less dissatisfaction with care (odds ratio=0.34, 95% Cl 0.2-0.59) and fewer drop-outs (odds ratio=0.61, 95% Cl 0.45-0.83). Duration of in-patient psychiatric treatment is shorter with community team management and costs of care are less, but there are no gains in clinical symptomatology or social functioning.

CONCLUSIONS

Community mental health team management is superior to standard care in promoting greater acceptance of treatment, and may also reduce hospital admission and avoid deaths by suicide. This model of care is effective and deserves encouragement.

Prospective studies of cothymia (mixed anxiety-depression): how do they inform clinical practice?

We suggest that the diagnosis of mixed anxiety depression at syndromal level (i.e. both anxiety and depressive diagnoses present in the same person and given equal status) is valuable clinically and should be introduced into the formal classification of neurotic and mood disorders. Evidence is given from a systematic review that cothymia has a significantly worse outcome than either an anxiety or a depressive diagnosis alone (p < 0.0001). Long-term follow-up data in a 12-year outcome study of neurotic disorder reinforce this finding both with regard to social functioning and the clinical course of anxiety and depressive disorders; these were significantly worse (P < 0.001 and P < 0.02 respectively) in those with cothymia compared with single anxiety disorders. These outcome differences are much greater than those between anxiety and depressive disorders alone.

Community mental health teams (CMHTs) for people with severe mental illnesses and disordered personality

BACKGROUND

Closure of asylums and institutions for the mentally ill, coupled with government policies focusing on reducing the number of hospital beds for people with severe mental illness in favour of providing care in a variety of non-hospital settings underpins the rationale behind care in the community. A major thrust towards community care has been the development of community mental health teams (CMHT).

OBJECTIVES

To evaluate the effects of community mental health team (CMHT) treatment for anyone with serious mental illness.

SEARCH STRATEGY

Electronic searches of Biological Abstracts (1982-1997), the Cochrane Library (1998, Issue 2), EMBASE (1980-1997), MEDLINE (1966-1997), PsycLIT (1974-1997) and SCISEARCH (1997) were undertaken. The Journal of Personality Disorders was hand searched, and contact was made with colleagues at ENMESH, ISSPD and in forensic psychiatry.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials of CMHT management versus non-team standard care.

DATA COLLECTION AND ANALYSIS

The selection of trials, assessment of quality and data extraction was undertaken independently and in parallel by two reviewers. Where possible the data were entered into RevMan and an intention-to-treat analysis undertaken. Tests of heterogeneity were undertaken.

MAIN RESULTS

CMHT management may be associated with fewer deaths by suicide and in suspicious circumstances (OR 0.32 CI 0.09-1.12). It causes less people to be dissatisfied with their care (OR 0.34 CI 0.2-0.59) and to leave the studies early (OR 0.61 CI 0.45-0.83). No clear difference was found in admission rates, overall clinical outcomes and duration of in-patient hospital treatment, although this was partly a consequence of poorly presented data.

REVIEWER'S CONCLUSIONS

Community mental health team management is not inferior to non-team standard care in any important respects and is superior in promoting greater acceptance of treatment. It may also be superior in reducing hospital admission and avoiding death by suicide.

Systematic review of the outcome of anxiety and depressive disorders

BACKGROUND

Although there have been many changes in the diagnosis of anxiety and depressive disorders in the past 20 years there have been few comparative enquiries into the clinical outcome of greater diagnostic categories. We therefore compared the outcome of all studies which compared the outcome of specific anxiety and depressive disorders using the standard procedures of systematic review.

METHOD

A Medline search was carried out of all studies comparing the outcome of anxiety and depressive disorders or mixed anxiety--depressive disorders in which information was available separately for each disorder.

RESULTS

Eight studies satisfied the search criteria (all involving a period of observation of two years or greater); only one of these included randomisation of treatment and comparison between specific anxiety disorder outcome. There was a somewhat better outcome in patients with depressive disorders compared with anxiety ones, and strong evidence that both anxiety and depressive disorders singly had better outcomes than comorbid mixed disorders.

CONCLUSION

Comorbid anxiety--depressive disorders have a poor outcome compared with single anxiety and depressive disorders, and there is some evidence that anxiety disorders have a worse outcome than depressive ones.

Glucocorticoids promote a TH2 cytokine response by CD4+ T cells in vitro

Purified rat CD4+ T cells were activated in vitro in the presence or absence of the glucocorticoid dexamethasone. They were then expanded in IL-2 and subsequently restimulated, this time in the absence of the hormone. The results indicate that the exposure of the cells to dexamethasone in the primary stimulation changed the cytokine synthesis induced by the secondary stimulation. The mRNA levels for IL-4, IL-10, and IL-13 were all increased by the pretreatment, whereas synthesis of IFN-gamma and TNF-alpha was diminished. Further studies in which IL-4 was used together with dexamethasone showed that the cytokine potentiated the effect of the hormone. These data suggest that the neuroendocrine system can influence the cytokine response to pathogens and autoantigens in a way that favors Th2-type reactions. There are similar implications for therapy with glucocorticoids, and these drugs may be expected to have long term immunologic effects as well as short-lived immunosuppressive ones. The production of a mouse mAb, MRC-OX81, against rat IL-4 is also described.

Glucocorticoids promote a TH2 cytokine response by CD4+ T cells in vitro

Purified rat CD4+ T cells were activated in vitro in the presence or absence of the glucocorticoid dexamethasone. They were then expanded in IL-2 and subsequently restimulated, this time in the absence of the hormone. The results indicate that the exposure of the cells to dexamethasone in the primary stimulation changed the cytokine synthesis induced by the secondary stimulation. The mRNA levels for IL-4, IL-10, and IL-13 were all increased by the pretreatment, whereas synthesis of IFN-gamma and TNF-alpha was diminished. Further studies in which IL-4 was used together with dexamethasone showed that the cytokine potentiated the effect of the hormone. These data suggest that the neuroendocrine system can influence the cytokine response to pathogens and autoantigens in a way that favors Th2-type reactions. There are similar implications for therapy with glucocorticoids, and these drugs may be expected to have long term immunologic effects as well as short-lived immunosuppressive ones. The production of a mouse mAb, MRC-OX81, against rat IL-4 is also described.

Prevention of experimental allergic encephalomyelitis in rats by targeting autoantigen to B cells: evidence that the protective mechanism depends on changes in the cytokine response and migratory properties of the autoantigen-specific T cells

Previous experiments from this laboratory have shown that Lewis rats were protected from experimental allergic encephalomyelitis (EAE) induced by the injection of myelin basic protein (MBP) in Freund's complete adjuvant if they were treated with the encephalitogenic peptide of MBP covalently linked to mouse anti-rat immunoglobulin (Ig) D. It was suggested that this protection developed because the antibody-peptide conjugate targeted the peptide to B cells and that this mode of presentation induced a Th2-like T cell response that controlled the concomitant encephalitogenic Th1 reaction to the autoantigen. The current experiments were carried out to test this hypothesis and to examine the alternative explanation for the protective effect of the conjugate pretreatment, namely that it induced a state of nonresponsiveness in the autoantigenspecific T cells. It was shown that EAE induction was suppressed in Lewis rats when the antibody-peptide conjugate was injected intravenously 14 and 7 d before immunization with MBP in adjuvant, but that anti-MBP antibody titers were at least as high in these animals as in controls that were not pretreated with the conjugate before immunization. Lymph node cells from these pretreated animals, while proliferating in vitro to MBP as vigorously as those from controls, produced less interferon gamma and were very inferior in their ability to transfer disease after this in vitro activation. In contrast, these same lymph node cells from protected rats generated markedly increased levels of messenger RNA for interleukin (IL)-4 and IL-13. When these in vitro experiments were repeated using the encephalitogenic peptide rather than MBP as the stimulus, the proliferative response of lymph node cells from pretreated donors was less than that from controls but was still readily detectable in the majority of experiments. Furthermore, the cytokine expression induced by the peptide was similar to that elicited by whole MBP. While these results support the original hypothesis that the anti-IgD-peptide conjugate pretreatment protected rats from EAE by inducing a Th2-type cytokine response, a totally unexpected finding was that this pretreatment greatly reduced the level of leukocyte infiltration into the central nervous system. This result provides a direct explanation for the protective effect of the pretreatment, but it raises questions regarding migratory and homing patterns of leukocytes activated by different immunological stimuli.

Public health, epidemiology and war

The delivery of humanitarian aid in wartime is difficult. However, it is essential that aid is provided in the most effective manner possible, targeted on those most in need whilst minimizing waste. Furthermore the delivery of aid should be sensitive to the future needs of the communities in conflict. This requires information on the needs of the vulnerable population. There is little experience of collecting data on the impact of war on a civilian population. The war in Bosnia disrupted surveillance of communicable disease. The local authorities were assisted by the World Health Organization in re-establishing surveillance. The data generated was valuable in planning interventions to minimise the possibility of major outbreaks of infection, reduce the impact of infectious disease and in guiding the humanitarian aid effort. The experience described suggests that public health surveillance of the civilian population in wartime is possible and useful. Besides the need for planning, the public health doctor in wartime has a role as an advocate for those suffering; this function can be carried out much more effectively if it is based on objective data collection rather than hearsay.

Decisions of practitioners regarding placement of amalgam and composite restorations in general practice settings

This study was undertaken to analyze the current reasons practitioners in general practice settings choose to place amalgam and composite restorations. Data were gathered on individual restorations in the clinical setting to provide information on reasons practitioners state that restorations are placed, the type of material most often placed in different restoration classifications, and the age of restorations at the time of replacement. The results of this study indicate that approximately one-half of all restorations, both amalgam and composite, were placed to treat primary caries. One-half of the remaining restorations placed, i.e., not including those with primary caries, were placed to treat recurrent caries. With respect to restorative materials, amalgam was most often placed in class 1 and class 2 situations (88.9% of the amalgam restorations reported), while composite was most often placed in class 3, 4, or 5 situations (77.4% of the composite restorations reported). From the total data set returned for replaced restorations, only 20% of the data forms reported on verified longevity of the restoration being replaced. Analysis of these data gave a calculated median longevity for amalgam and composite restorations of 10 years and 5 years respectively.

Human resource development: the management, planning and training of health personnel

The morale of health personnel is fast becoming the major factor affecting both the sustainability and the quality of health care world-wide. Low morale mirrors problems ranging from declining balance of payments allocation to GNP, and a lack of support for the health system from the very top down to the rigid application of national pay, grading and career structures, and the stress of not being able to do the job properly. While many of these and other problems have been voiced again and again in the press and in the academic literature, much of the work on health manpower development has focused on the planning and production of personnel. This has been with the aim of producing specific categories of better-trained health workers with relevant qualifications, resulting in a heavy emphasis on a quantitative output. In this paper it is argued that the management of health personnel, the qualitative aspect of staff development, has been relatively neglected. Unless and until the management of human resource development receives the attention it needs, seeds of discontent, disillusion and dissatisfaction will ultimately lead to national health services losing their competitiveness as employers. The sustainability and quality of health programmes will then be in even greater jeopardy than they are at present. The planning, production and management components of health manpower development have developed haphazardly as verticle activities. A new term such as 'human resource development; the management of health personnel' might help ensure the concept of an integrated process contingent on economic, political, organizational and other important circumstances.

The usefulness of dye-penetration studies reexamined

An in vitro study to determine the usefulness of dye-penetration studies was conducted. In part I, teeth were prepared through the foramen and then left open, either apically, coronally, or at both ends. In all cases, the dye did not penetrate the full length of the canal. The only exception was when both ends were left open and the teeth were placed into the dye in an upright position. In part II, a measurable defect in a canal filling the length of the canal was created and left open apically. When the tooth was immersed in dye, the penetration was incomplete. When the air was removed by vacuum pump prior to placement in the dye, the penetration was total. The validity of dye studies that do not consider entrapped air is open to question.

Refugee income generating projects and occupational health

The shift from purely emergency relief for refugees in developing countries to aid within the context of development strategies is slowly gathering momentum (UN, 1983; UNHCR, 1984; Simmonds, 1984). Such a move implies that if self-reliance is to be a realistic goal then employment for refugees is essential; a number of income-generating schemes are therefore being both proposed and developed (ILO, 1983 and 1984). Many of these schemes have implications for the health of the refugees, so this paper summarises some occupational health hazards and offers suggestions for future action.

Mortality of workers exposed to styrene in the manufacture of glass-reinforced plastics

Epidemiologic studies have suggested an increased risk of leukemia and lymphoma among workers exposed to styrene. In a further exploration of this possible hazard, an analysis was conducted of the mortality among 7,949 men and women employed during 1947-1984 in eight British companies manufacturing glass-reinforced plastics. The subjects were identified from company files and traced to the end of 1984 through National Health Service and National Insurance records. The overall mortality in the cohort was less than in the national population (693 deaths observed, 830.1 expected) as was mortality from cancer (181 deaths observed, 223.7 expected). In particular, there was a deficit of deaths from lymphoid and hemopoietic cancer (6 observed, 14.9 expected). The small excess of lung cancer (89 deaths observed, 80.1 expected) was not statistically significant and can probably be attributed to chance. Among 3,494 hand laminators (the job with the highest exposure to styrene) there was one death from lymphoma and none from leukemia. The findings do not exclude the possibility that styrene is a human carcinogen, but give no support to the hypothesis that it causes leukemia and lymphoma.

A case-control study of acute appendicitis and diet in children

The diets of 53 Southampton children who had had appendicitis were compared with those of two sets of age-sex matched controls using a seven-day weighed food record. One set of controls comprised classmates of the cases; the other was a random sample of all schoolchildren in the city. The cases weighed less and were shorter in height; they had lower intakes of energy, all the main nutrients and water. The differences in weight and water intake were statistically significant. Low water intake was identified as a risk factor independent of other factors. Consumption of dietary fibre from cereals and vegetables in relation to total energy intake and body weight was similar in cases and controls.

Training refugees as primary health care workers: Past imperfect, future conditional

Many problems have been encountered in the planning and implementation of health care in refugee camps, and more specifically in the training of refugees as primary health care workers. A review of the published literature and a "survey" of the opinions and experiences of refugee, national and international health personnel regarding training has therefore been undertaken to provide an overview of what has been done and to make recommendations for future work. The review highlights the need to reallocate resources away from high visibility emergency aid to development activities, such as training, that will create an infrastructure for primary health care and promote self-reliance.

Refugee health care: Similar but different?

The present review sets out to identify differences between refugees and other more stable communities living in less developed countries: demographic, mortality, morbidity, nutritional and selected epidemiological data are discussed. Although generalizations are difficult because of the variability of refugees and their differing circumstances, the health problems and diseases do not appear to differ qualitatively, although they may be quantitatively more severe. The areas of particular concern lie not so much with the problems but with approaches to their solutions: the need to respond rapidly and appropriately to emergencies, the importance of attending to the priorities of nutrition, shelter, sanitation and water; and the necessity of providing services which are sufficiently flexible and sensitive to the changing needs of the refugees as they move from the acute emergency to the long-term settlements. The review highlights certain areas where insufficient information is currently available, notably mental illness and the long-term issues of health and development, and outlines the implications of the conclusions for policy makers, with particular reference to training and research.

Soluble di- and aminopeptidases in Escherichia K-12. Dispensible enzymes

As part of a study of the peptidase content of Escherichia coli K-12, two peptidase-deficient amino acid auxotrophs isolated and characterized by Miller as pepD- (strain CM17) and pepD- pepN- pepA- pepB- pepQ- (strain CM89) were examined for the presence of several peptidases previously obtained from strain K-12 in this laboratory. The soluble fraction of each mutant was found to lack the broad-specificity strain K-12 dipeptidase DP and the strain CM89 fraction also lacked activity characteristic of the strain K-12 aminopeptidases AP, L, and OP; like strain CM17, strain CM89 contained the tripeptide-specific aminopeptidase TP. Strain CM89 (but not CM17) appeared to contain little if any activity attributable to the ribosome-bound aminopeptidase I of strain K-12. Whereas loss of DP, AP, OP, and aminopeptidase I activity may be attributed to the pepD-, pepB-, pepN-, and pepA- mutations, respectively, the reason for the loss of L activity remains uncertain. Grown responses of strain CM89 in liquid media containing di- or tripeptides were in accord with absence of enzymes catalyzing rapid hydrolysis of dipeptides. In synthetic liquid media supplemented with the required amino acids per se or with peptone, cultures of both CM strains grew more slowly than strain K-12 and produced smaller cell-yields than those produced by strain K-12.

Soluble tri- and dipeptidases in Escherichia coli K-12+

As part of a study of the metabolic role of peptidases in Escherichia coli K-12, cell extracts were examined for the presence of three enzymes originally identified [Sussman, A. J., and Gilvarg, C. (1970), J. Biol. Chem. 245, 6518] in extracts of the lysine auxotroph ASO13 by virtue of their activity toward lysine homopolymers. It has now been shown that the activity ascribed to a Co2+-dependent dilysine-specific enzyme is a function of the strain K-12 dipeptidase DP, a metal-dependent enzyme active toward a variety of dipeptides, and that the activity ascribed to a trilysine-specific enzyme is a function of the strain K-12 tripeptidase TP, an aminopeptidase capable of hydrolyzing substrates in the series X-Gly-Gly, X-Gly-X, and X-Leu-Gly (where X is Leu or Met) but devoid of activity toward dipeptides. The third enzyme, an oligopeptidase not previously observed in strain K-12, was found to include among its substrates not only di- and trilysine but other di- and tripeptides that are hydrolyzed by the di-and tripeptidase as well as by aminopeptidases L and AP; the aminopeptidases, however, lack activity toward di- and trilysine. The absence of oligopeptidase activity from extracts of strain AJOO5, a "PEPTIDE-DEFICIENT MUTANT" derived from strain ASO13 by Sussman and Gilvarg, has been confirmed, and strain AJOO5 has been shown to contain all the other peptidases known to be present in strain K-12. Possible functions of the oligopeptidase are proposed on the basis of its observed activity in vitro and of the basis of its observed activity in vitro and of the differences between the growth responses of strains AJOO5 and ASO13 in various media. Some general aspects of peptide metabolism are discussed with emphasis on the use of peptidase-deficient mutants in the study of this problem, and methods that may prove helpful in the isolation of such mutants are suggested.