[Possibilities of using plasma flow in lung surgery].

Experiments on 10 mongrel dogs demonstrated the efficacy and reliability of argon plasma flux in achieving hemo- and aerostasis in surgical debridement of gunshot wounds of the chest "Fakel" plasma surgical complexes were used as a source of plasma. A total of 43 operations were performed on patients whose ages ranged from 16 to 68 years: pulmonectomy 3, lobectomy 24, bilobectomy 4, atypical resection of the lung 4, pleurectomy with lung decortication 5, diagnostic thoracotomy 2, rib resection 1. Argon plasma flux was used in thoracotomy, treatment of wound surfaces of the lungs and pleura, separation of the interlobar fissures, and division of the main and lobar bronchi. The plasma flux produced an analgesic effect; as a result much less narcotics and analgesics were needed and physical activity was permitted earlier. The amount of discharge from the pleural cavity along the drain was 1.5-2 times less (200 +/- 40 ml) as compared to that in the traditional methods for conducting similar operations. No complications associated with application of plasma flux were noted. Incompetence of the bronchial stump, rethoracotomy for bleeding or suppuration were not encountered.


[Effect of subtotal resection of costal cartilage on the basic chest dimensions in children with funnel chest deformity].

The paper summarizes the results of anthropometric and computed tomographic studies of the external and internal chest dimensions in 86 patients with Degree II-III infundibuliform chest deformity. Full resection of deformed cartilages of the third to seventh ribs has been examined for its impact. The children with infundibuliform chest deformity have been found to have an impressed anteroposterior dimension of the bilateral chest. The transversal and anteroposterior dimensions of the chest remain unchanged after removal of cartilages. The chest enlarges only sagittaly. One- and three-year follow-ups have indicated that full removal of the deformed cartilage has no impact on the growth of the chest.


[External respiratory function in children with bilateral, chronic, nonspecific inflammatory disease of the lungs after surgical treatment].

The results of operative treatment of children with bilateral chronic unspecific inflammatory diseases of the lungs were studied in follow-up periods of up to 17 years. Among the 73 patients studied, 19 had a history of bilateral and the remaining a history of unilateral resections. According to the findings of respiratory function examination, a combined type of ventilation disorders with mild hypoxemia and hypercapnia was characteristic of this group of patients before the operation. In the postoperative period the restrictive syndrome intensifies because the volume loss is not compensated for. There is a discrepancy between the clinical and functional data in evaluation of the results of the operation. However, in cases of good clinical results after extensive resections of the lungs a positive dynamics of the ventilation capacity of the lungs with increased oxygen tension in the arterial blood is recorded.


[Aorto-coronary and mammary-coronary bypass of the working heart without extracorporeal circulation in patients with ischemic heart disease and a history of two or more myocardial infarctions].

The paper shows how successfully surgical myocardial revascularization can be performed on the working heart without applying extracorporeal circulation in 17 patients with a history of two or more myocardial infarctions. Deaths were not observed among the patients operated on. The follow-ups of the patients were 1-2 months.


Why do patients consult the general practitioner? Determinants of their decision.

In order to obtain more information about the reasons why patients consult their general practitioner 1000 patients completed a questionnaire in the waiting rooms of eight general practices. After the consultation the patients received a second questionnaire. The aim of the study was to determine why people decide to consult their general practitioner about one complaint but not about a second complaint. Both questionnaires were based on the health belief model, augmented by three other factors: the perceptions patients have of their own abilities to cope with their condition (efficacy of self care), their knowledge about the complaint and their need for information. The results showed that two of the additional factors (efficacy of self care and need for information) as well as most of the factors of the health belief model (efficacy of general practitioner care, perceived severity of complaint and cues to consult) were important determinants of consulting the general practitioner. The results suggest that patients sometimes expect information from their general practitioner rather than medical treatment. Furthermore, as the perceived efficacy of general practitioner care is also an important determinant, unnecessary consultation or unnecessary delay in treatment could be prevented by offering patients information about the potential effectiveness of medical care or self care for specific conditions. Implications for general practitioners' daily practice and future research are discussed.


Comparison of the use of four desktop analysers in six urban general practices.

There is little data on the advantages and disadvantages of using desktop analysers in general practice. This prospective trial compared four of the analysers available in the United Kingdom, in six urban general practices, over a six month period. Of the 2619 tests where the time was noted, 55.8% were performed outside the hours when routine transport to a hospital laboratory was possible (after 12.00 hours). Of the 3530 tests performed the commonest were measurements of cholesterol (14.4 tests per 5000 patients per 30 days), glucose (6.0 tests) and haemoglobin (5.6 tests). Less than 5% of the tests were performed as an emergency despite the speed at which results are available. The main reasons for requesting the tests were screening or case finding (56.9%), with the remainder for monitoring chronic disease, especially diabetes and hypercholesterolaemia. There was evidence that the use of the machines in the four practices reduced requests for hospital laboratory blood tests by 24-40% of pre-study levels. However, there was a considerable increase in testing for cholesterol (three fold) and haemoglobin (eight fold) on the desktop analysers, compared with the number of laboratory tests requested before the study. The cost per test of using such machines is closely related to the level of activity and probably does not compete favourably with hospital testing unless several tests are performed each day. Quality control tests were within the specified limits on at least 98% of occasions, however these tests also identified the need for laboratory back up where a problem was found.


Attitudes to community psychiatry among urban and rural general practitioners.

General practitioners' requirements for community psychiatric services may differ according to the area in which they practise. A questionnaire survey of general practitioners' attitudes to community psychiatric services is reported from three contrasting areas: an inner city urban area, a new town and a rural area. General practitioners in all areas wanted more consultation with psychiatrists, and 53-68% wanted regular psychiatric outpatient clinics in their surgeries. There was enthusiasm for community psychiatric nurses and for help with psychotherapy. In the rural area general practitioners favoured surgery based psychiatric outpatient clinics and arranging emergency hospital admissions themselves; in urban areas domiciliary visits from psychiatrists to help with emergencies were favoured. These results appear to reflect the greater geographical distance between primary and hospital based secondary care in rural as opposed to urban areas. Overall, general practitioners wanted more support from community psychiatric services in carrying out their primary therapeutic role especially in rural areas far from hospital-based psychiatric services.


Study of patients who chose private health care for treatment.

A questionnaire survey was carried out in 1991 in Wessex regional health authority of a sample of private patients having inpatient treatment in eight independent hospitals, and in pay beds in three National Health Service hospitals. A total of 649 patients replied (response rate 60.7%). Sixty respondents to the questionnaire were also interviewed. The aim of the study was to discover which groups of people chose private care rather than using the NHS, and why. In view of the current emphasis on consumerism in health care, the study also aimed to examine how patients exercised choice in a market situation and how well informed they were when they did so. The questionnaire asked about the role and influence of the general practitioner in patients' decisions to use private health care for treatment. The largest group of respondents were in the 36-50 years age group (34.2%). Of the respondents 59.9% were women, 54.1% were in social class 2 and 77.3% were married or cohabiting. The most common reason for using private health care for treatment was to avoid NHS waiting lists (61.5% of respondents) although they did not necessarily know how long that wait would have been. Patients sought their general practitioner's opinion about whether to use private health care in 187 cases (28.8%). The majority of the 649 patients (71.2%) had decided to use private health care before consulting the general practitioner. However, patients were influenced by their general practitioner's advice on the choice of consultant and choice of hospital.(ABSTRACT TRUNCATED AT 250 WORDS)


Diagnostic yield from barium enemas: a study among patients referred by general practitioners and hospital outpatient departments.

Although the double contrast barium enema is the standard radiological examination of the colon, it is not universally available to patients referred by their general practitioners. A retrospective survey of all double contrast barium enemas carried out over a two year period in one health district was undertaken to determine the diagnostic yield of pathological findings for patients referred by general practitioners and hospital outpatient departments and for patients who had rigid sigmoidoscopy prior to the enema and those who did not. A total of 530 patients were studied. The diagnostic yield for the hospital outpatients was 41.6% and in the general practitioner group 35.6%. In the patients who had rigid sigmoidoscopy the yield was 42.7% compared with 32.6% in those who had no prior sigmoidoscopy. It is concluded that the withdrawal of direct access for barium enemas to general practitioner patients in this district because of a low diagnostic yield cannot be justified. The lower diagnostic yield in the patients who did not have sigmoidoscopy supports the policy of requiring this examination prior to all barium enemas.


Audit and academic departments of general practice: a survey in the United Kingdom and Eire.

A questionnaire and telephone survey was carried out in April 1991 of all 31 academic departments of general practice in the United Kingdom and Eire; 30 departments responded. The aim of the study was to assess the departments' level of involvement in teaching about audit in the undergraduate curriculum, their role in the development of audit in primary care including involvement with medical audit advisory groups, whether they undertook teaching about audit to other health professionals and whether they were involved in audit related research. Eleven of 27 responding undergraduate departments provided formal teaching about audit and five intended to introduce it in the near future. Respondents expressed concerns about teaching audit to undergraduates, including lack of time in the curriculum, difficulties making the teaching relevant and interesting, and a lack of expertise and knowledge of the subject among the staff. All 29 departments in the UK were represented on medical audit advisory groups, and audit related research was being carried out in 24 undergraduate departments. The role of academic departments of general practice in the development of audit in primary care is discussed.


Abnormal cervical smear test results: old dilemmas and new directions.

Primary care professionals play a major role in the cervical screening programme in the United Kingdom, especially since the new contract for general practitioners. Many aspects of the programme are still the subject of broad debate and detailed research. New policies regarding the programme are generated at various levels; feedback is not always made directly available to primary care teams. This review article attempts to summarize the current available literature on cervical screening, focusing on the meaning of minor degrees of dysplasia, cervical cancer in younger women, the role of the wart virus, frequency of smear tests, diagnosis and treatment, counselling, and concludes with practical advice to help the practice team.


Paternalism and the doctor-patient relationship in general practice.

This paper is a brief introduction to the subject of paternalism as it occurs in general practice. A definition of paternalism is provided and the four main types of doctor-patient relationship within the paternalistic spectrum are described. These relationships are illustrated with examples from general practice. Some of the extensive literature on paternalism is reviewed. It is concluded that paternalism is rarely justified when treating patients of sound mind and then only where restoration of the patients' autonomy is the main aim.


A survey of links between mental health professionals and general practice in six district health authorities.

The aim of this study was to obtain an estimate of the extent to which collaborative schemes exist between general practice and mental health professionals and to assess the influence of practice size and district on these schemes. A questionnaire asking about such links was sent to each general practice in six randomly selected health districts in England. The response rate was 75%. Half of the 261 responding practices had a link with a community psychiatric nurse, 21% with a social worker, 17% with a counsellor, 15% with a clinical psychologist and 16% with a psychiatrist. Practices with more general practitioners were significantly more likely to have a link with a counsellor, after allowing for marked differences between the sizes of practices in the different districts. There was a tendency for some practices to have many links, while others had few. This poses questions about the efficiency and equity of collaborative schemes in primary care. Further research is required to investigate the quality of these links and the extent to which they serve the interests of the patient.


Drug consumption during the first 18 months of life of infants from smoking and non-smoking families.

In a geographically well defined population in southern Sweden, a study was made of the overall consumption of drugs by infants during their first 18 months of life. The study population comprised 240 infants, of whom 90 were from families where tobacco was smoked by one or both parents and 150 were from non-smoking families. The investigation was carried out retrospectively by interviewing the mothers at the routine 18-month check up at the child health clinic, combined with study of the medical records at the district health centre, and at the paediatric and ear, nose and throat departments of the nearby hospital. In addition, the reliability of the interview method compared with review of medical records was investigated. Particular attention was paid to the consumption of antibiotics and the relationship between 'passive smoking' and consumption of antibiotics necessitated by respiratory tract infections. There was widespread use of both prescribed and non-prescription remedies. At the age of 18 months, about two thirds of all infants in the area had been prescribed an antibiotic (or other antibacterial agent) on at least one occasion. Infants from smoking families had been prescribed significantly more antibiotics than had infants from non-smoking families. The same pattern was also apparent for nose drops and dimethicone/dicyclomine hydrochloride. The incidence of respiratory tract infections requiring antibiotic treatment was higher in infants from smoking families than from non-smoking families in all the three-month age groups up to 15 months. The responses to the retrospective interview accorded closely with the details recorded in the medical records.(ABSTRACT TRUNCATED AT 250 WORDS)


Morbidity in early childhood: differences between girls and boys under 10 years old.

The aim of the study was to investigate the differences in presented morbidity and use of health services among boys and girls in early childhood. The study was performed using data collected by the continuous morbidity registration project of the department of general practice at Nijmegen University. All recorded morbidity, referrals to specialists and admissions to hospitals were recorded by the registration project. The study population included children born in four practices from 1971 to 1984. The children were followed up until the age of five years and if possible until the age of 10 years. The morbidity of the children had been categorized into three levels of seriousness of diagnosis and 15 diagnostic groups as part of the registration project. Boys presented more morbidity than girls in the first years of their lives. For the age group 0-4 years this was true for all levels of seriousness of diagnosis except the most serious. In this younger age group significantly more boys than girls suffered respiratory diseases, behaviour disorders, gastroenteritis and accidents. Girls suffered from more episodes of urinary infection than boys in both age groups. More boys were referred to specialists and admitted to hospital than girls. The findings of this study suggest that not only inborn factors can explain the sex differences in presented morbidity and use of health services in early childhood. In particular, differences between girls and boys in terms of non-serious morbidity and referral and admission rates suggest a different way of handling health problems in boys and girls in early childhood both by parents and doctors.(ABSTRACT TRUNCATED AT 250 WORDS)


Systematic care of diabetic patients in one general practice: how much does it cost?

This study examines the costs of running a method of systematic care for diabetic patients in one general practice--the monthly 'diabetic day'. Doctor, nurse, chiropodist, dietitian, clerical officer, building and stationery costs were included in the evaluation. The study took place in an inner city practice of seven partners based in a health centre. The cost per year of running the diabetic days was 1854.53 pounds to the practice and 4465.69 pounds to the National Health Service (1989 prices). The cost to the practice included family health services authority reimbursements and excluded the cost of the chiropodist and dietitian. The cost per attendance was 38.17 pounds to the NHS and 15.85 pounds to the practice while the cost per patient per year was 58.00 pounds to the NHS and 24.08 pounds to the practice. The practice suffered a net loss after taking into account health promotion clinic payments received from the family health services authority. The cost to the NHS of each attendance at the practice was considerably greater than estimates of the cost of attendance at the outpatients department of a local trust hospital. However, it is argued that general practice has an essential role in the improvement of diabetic surveillance, and that an adequate remuneration package could transform the care of many patients with diabetes.


Pre-recorded answerphone messages: influence on patients' feelings and behaviour in out of hours requests for visits.

The aim of this qualitative study was to investigate the feelings and behaviour of patients requesting out of hours visits on hearing pre-recorded answerphone messages. Actual messages which had been recorded were classified by a group of four people. Examples of each type of message were then played to a second group, of six people, who expressed their feelings about the varying messages. A third group, of 10 people, was asked to invent hypothetical emergency situations of increasing severity. For each of the emergency situations their proposed actions on hearing the different types of answerphone message were recorded. The results showed that people preferred short messages telling them what to do in an emergency and the time of the next surgery. They also felt that the message should be recorded by a doctor and not a receptionist and be delivered in a 'neutral' tone. Proposed actions were not influenced by the content of the message or the person recording the message. The most important factor in deciding which action to take was the tone of the message. A 'strict' rather than a 'neutral' tone tended to discourage patients from calling out their doctor and was more likely to lead to inappropriate responses. It is suggested that answerphone messages recorded by the doctor, stating what to do in an emergency and the time of the next surgery, delivered in a neutral rather than a strict tone, will lead to the most appropriate responses from patients.


Risk factors for coronary heart disease: a study in inner London.

A survey was carried out among 281 men and women aged between 30 and 64 years randomly selected from five general practices located in the inner London borough of Tower Hamlets, to determine the prevalence of risk factors for coronary heart disease. Smoking and obesity were both more pronounced in Tower Hamlets than in comparable national studies: 51% of men and 44% of women were smokers and 57% of these were smoking 20 or more cigarettes per day. A body mass index of 30 or more was present in 18% of men and 10% of women and a body mass index of 25 or more in 71% of men and 49% of women. Two or more risk factors for coronary heart disease (smoking and/or hypertension and/or raised cholesterol levels) were present in 25% of men and 22% of women. For every person known by their general practitioner to have established cardiovascular disease, there were an additional two people also at risk on the basis of multiple risk factors. In this inner city population the prevalence of cardiovascular risk, for women as well as men, has major resource and organizational implications for primary care. A strategy for change requires action based on graded multiple risks for both men and women.


Improving mental health through primary care.

The government white paper Health of the nation has highlighted mental health as a key issue for the next decade. Primary care is being encouraged to take a leading role in developing effective services for people with mental health problems. This paper reviews current research on key aspects of mental health in adults: the prevalence of mental health problems, improving detection and management of mental health problems, the role of counselling, and communication between primary and secondary care. Recommendations are made for initiatives in both research and service development.


Involvement of lay visitors in general practice assessment visits.

Six practice assessment visits which jointly involved lay and medical visitors were arranged by the patient liaison group of the Royal College of General Practitioners. These visits were inspired by the 'What sort of doctor' report published by the RCGP in 1985. A subgroup of the patient liaison group adapted the assessment grid from the report to take account of involving lay visitors with doctors on practice visits. The visits were educationally valuable to the lay visitors, and also prompted some practical changes in the practices. This experiment might have further application in the development of fellowship by assessment or even in the process of reaccreditation of general practitioners.


The dilemma of AIDS vaccine and therapy. Possible clues from comparative pathogenesis with measles.

AIDS viruses, because of their unique properties, are extraordinary. Past successes achieved with vaccines against ordinary viruses do not provide the guidelines needed to develop successful vaccines against HIV. Neither vaccines nor drugs can be relied upon to provide an answer to AIDS. AIDS is a disease of immune dysfunction and destruction, and an alternative to prevention of infection or cure might lie with elimination of the clinical consequences of infection. This might find a basis in precise definition of its pathogenesis. The enormity of possible pathogenetic changes in HIV infection invites simplification, and might be aided by a search for clues among ordinary viruses in which there is a less complicated biology and spontaneous recovery from infection. Measles virus infection presents analogies to AIDS, especially in the induction of anergy and increased mortality, in the long term, from diseases other than measles as observed in children infected during early life. This was demonstrated recently in increased deaths, all causes, during a three-year period among infants who were given live measles virus vaccine of high infectivity titer during early infancy, sometimes in the presence of maternal antibody. AIDS and measles may be diseases of similar pathogenesis, but with the difference that AIDS immunopathology is progressive while that for measles is regressive.


Kaposi's sarcoma: a review of gene expression and ultrastructure of KS spindle cells in vivo.

The ultrastructural features and the gene expression pattern of Kaposi's sarcoma (KS) spindle cells in vivo suggest that KS is a tumor of the mixed cell type. The expression pattern of cytokines and cytokine receptors in the tumor lesion, together with the results obtained from in vitro characterization of KS-derived cells, provide evidence that paracrine mechanisms of growth factor action are important for the maintenance of KS. The reports on virus infection of KS cells suggest an indirect role of virus infection in the induction of KS, most likely mediated by immunostimulation and subsequent production of cytokines.


The control of the antibody isotype response to recombinant human immunodeficiency virus gp120 antigen by adjuvants.

Both saponin and muramyl dipeptide (MDP) formulated with a squalane-in-water emulsion of large particle size prepared with a vortex mixer were superior to Al(OH)3 as adjuvants for HIV gp120 in mice. All the adjuvants induced IgG1 antibody, but saponin elicited the highest titers of IgG2a. The secretion of interleukin-5 (IL-5) and interferon gamma (IFN gamma) by lymph node cells cultured in vitro with gp120 was studied. All the cultures secreted IL-5, but only those from saponin-immunized mice produced IFN gamma, suggesting that saponin is capable of activating both the Th1 and TH2 T-cell subsets. The titers of neutralizing antibodies were low with both MDP and saponin, and they occurred in mice which were also positive for antibodies against a V3 loop peptide. Glucosaminylmuramyl dipeptide (GMDP) which is less pyrogenic than MDP and a nonpyrogenic analog GMDPA, displayed equivalent adjuvant activity to MDP. The level and isotype composition of antibodies induced by GMDP in combination with squalane emulsions depended on the dimension of the emulsion particles. With a large (2500 nm) particle size the response was confined to IgG1 in Balb/c mice, but when this was reduced to 150 nm by sonication the antibody response was increased and relatively high levels of IgG2a appeared in some mice.


Serum IgA subclasses and molecular forms in HIV infection: selective increases in monomer and apparent restriction of the antibody response to IgA1 antibodies mainly directed at env glycoproteins.

In a study population representing different CDC stages of HIV infection, 58% exhibited IgA hypergammaglobulinemia resulting from proportional increases in both the IgA1 and the IgA2 subclasses. These increases were detected early in infection, did not correlate with CD4 count, and remained elevated throughout disease progression. Absolute concentrations of polymeric IgA present within each subclass were unchanged, indicating that increased production of monomeric IgA1 and IgA2 were responsible for elevations of total IgA. These elevations were not completely attributable to a specific antibody response to viral infection, since Western blot analysis of purified IgA samples indicated that HIV-reactive IgA antibodies could be demonstrated only within the IgA1 subclass. Dominating IgA1 anti-HIV responses were also observed in two secretory IgA samples isolated from colostrum of healthy HIV seropositive mothers, suggesting that a similar isotype restriction exists in the mucosal IgA compartment. The binding of IgA1 to HIV proteins contrasted markedly to that observed with identical concentrations of IgG purified from the sera of the same patients. While IgG reacted more intensely and broadly with all HIV proteins, IgA1 antibodies were directed predominantly against envelope glycoproteins. In many patients, a total lack of IgA1 reactivity to gag and pol proteins was accompanied by intact IgG responses to these same antigens. Though all IgA samples examined reacted with HIV, fewer responses to gp160, gp120, and p24 were observed in samples from AIDS and AIDS-related complex (ARC) patients, suggesting a declining titer of IgA antibodies against these antigens may be associated with disease progression.(ABSTRACT TRUNCATED AT 250 WORDS)


HIV-1 matrix protein p17 resides in cell nuclei in association with genomic RNA.

We have shown previously that HIV-1 matrix protein p17 is transported to the nucleus of Jurkat-tat and H9 cells soon after infection. As shown in this combination, gag polyprotein p55 synthesized 48 h after cell infection is cleaved in cytosol rapidly after its synthesis, and nascent p17 enters the nuclei and gradually accumulates there. Uncleaved p55 molecules and intermediate precursors are rapidly transported to the membranes and are also found in nuclei. Mature gag proteins are seen in membranes only after prolonged period of labelling or chase (4 or more hours later). To determine whether the nascent p17 is associated with viral genomic RNA in the nuclei, the cells were fractionated, the viral complexes were immunoprecipitated by monoclonal antibodies (MAbs) against gag proteins, and RNA was extracted and analyzed by slot and blot hybridization. MAb against p17 precipitated all the viral RNA from the nuclei including full-size genomic RNA and essential parts from membranes while MAb against p24 did not precipitate any viral RNA from the nuclei. These data suggest that matrix protein is linked to genomic RNA in the nuclei and raise the possibility that p17 may transfer viral nucleocapsids from the nuclei to plasma membranes, the site of virus assembly.


Genetic and functional analysis of a set of HIV-1 envelope genes obtained from biological clones with varying syncytium-inducing capacities.

To study HIV-1 envelope-mediated syncytium formation we have amplified, cloned, expressed, and sequenced individual envelope genes from a set of eight biological HIV-1 clones. These clones were obtained from two patients and display either a syncytium-inducing (SI) or nonsyncytium-inducing (NSI) phenotype. Upon expression through recombinant vaccinia virus, individual envelope gene products display heterogeneous syncytium-inducing capacities which reflect the phenotype of the parental biological HIV-1 clones in all cases. For the eight biological HIV-1 clones presented here, variation of the envelope gene alone is sufficient to explain the observed variable syncytium-inducing capacity of the respective parental viruses. In addition we determined the complete nucleotide sequence of these envelope genes. The predicted amino acid sequence revealed a considerable amount of variation located mainly in the previously denominated variable regions. In various regions of envelope genes obtained from the same patient, phenotype associated amino acid variation was found. This phenotype associated amino acid variation however, is not conserved between the two sets of envelope genes derived from different patients. Four envelope sequences derived from clones obtained from one patient showed phenotype-associated amino acid variation in the fusion domain. Sequencing of 12 additional fusion domains revealed that this same variation is found in four additional clones. However, a functional test performed on recombinant vaccinia expressing mutant envelope genes showed that this observed fusion domain variation does not contribute to the variation in syncytium-inducing capacity of the envelope gene product.


HIV-1-induced cytopathogenicity in cell culture despite very decreased amounts of fusion-competent viral glycoprotein.

In order to examine the potential role of env-induced membrane fusion in the cytopathogenic properties of HIV-1 in cell culture, the effects of mutations within the proteolytic cleavage site of gp160, which result in a reduction but not a complete absence of proteolytic processing have been further studied. Cells expressing the mutant glycoproteins were shown to be severely reduced in their capacity to form syncytia. However, viruses encoding these glycoproteins could infect cell culture cells, albeit with delayed kinetics, and, at late infection time points, resulted in complete cytolysis of the infected culture. Since amplification by polymerase chain reaction and direct sequencing of the DNA in the infected cultures confirmed the presence of the mutant and the absence of revertant DNA, this shows that the amount of fusion competent viral glycoprotein does not influence HIV-1 cytopathogenicity, but rather that other parameters must be involved in inducing cell death.


Properties of HIV membrane reconstituted from its recombinant gp160 envelope glycoprotein.

Human immunodeficiency virus (HIV) membrane has been reconstituted from the recombinant envelope glycoprotein precursor (gp160) by a detergent dialysis technique. Electron microscopy shows that gp160-virosomes are spherical vesicles with a mean diameter identical to that of viral particles. Enzyme-linked immunosorbent assay and immunogold labeling demonstrate efficient association of gp160 with lipid vesicles and proteolysis treatment reveals an asymmetric insertion with about 90% of glycoproteins having their gp120-moiety pointing outside. Glycoproteins are organized as dimers and tetramers and gp160 retains its ability to specifically bind CD4 receptor after reconstitution into virosome.


Relevance of the quantitative detection of HIV proviral sequences in PBMC of infected individuals.

Changes in HIV replication during progression of HIV infection were assessed by estimation of the number of peripheral blood mononuclear cells (PBMC) harboring HIV proviral sequences. Samples from 23 patients at different stages of HIV infection were analyzed by quantitative polymerase chain reaction (PCR) using GAG primers. HIV titers in PBMC were also determined by serial dilutions of cells in coculture with phytohemagglutinin-activated normal PBMC. A positive correlation was observed between the number of HIV DNA copies and the HIV titer in PBMC. The PCR test was more sensitive than the coculture technique. The number of HIV copies detected by PCR ranged from 50 to 10,500 per 10(6) PBMC: assuming one copy per cell this implies a frequency of proviral HIV-containing cells of one per 100 to one per 20,000 mononuclear cells. The mean number of HIV DNA sequences in PBMC was significantly lower in asymptomatic patients than in AIDS patients and patients with AIDS-related complex (ARC). In patients who progressed from asymptomatic infection to AIDS, the number of HIV DNA copies in PBMC rose, indicating an increase of HIV replication. These results show that the number of infected PBMC increases during clinical progression. However, some asymptomatic patients had a higher number of HIV DNA copies in their PBMCs suggesting that increased HIV replication precedes the appearance of clinical symptoms.


Signature pattern analysis: a method for assessing viral sequence relatedness.

Signature pattern analysis identifies particular sites in amino acid or nucleic acid alignments of variable sequences that are distinctly representative of a query set of sequences relative to a background set. We explore the merits of using signature patterns for analysis of HIV-1 (human immunodeficiency virus type 1) sequences in cases of epidemiological linkage and potential superinfection. For these purposes, query sets are viral sequences that are all derived from one HIV-1 infected individual, hence the signature pattern is the array of sites that are characteristic of the range of viral variants obtained from that person. Once a signature pattern has been objectively defined, it can be used to examine other viral sequences from other individuals for evidence of genetic relatedness. A computer program to facilitate this analysis, VESPA, is described and applied to sequence data gathered during the investigation of HIV-1 transmission in a dental practice. The implications of signature polymorphisms seen within an infected individual, and shared polymorphisms between linked individuals, are also considered. VESPA may also be applied to the molecular analysis of biological phenotypes.


Conserved structural features in the interaction between retroviral surface and transmembrane glycoproteins?

Among the retroviruses, the surface (SU) and transmembrane (TM) glycoproteins of lentiviruses are linked exclusively by noncovalent bonds. For some C-type retroviruses, however, a small proportion of the SU proteins has been shown to be linked to their TM proteins by a disulfide bond, with the remainder being noncovalently associated. A region near the carboxyl terminus of the HIV-1 SU glycoprotein has been implicated in contacting the TM glycoprotein. Computer modelling indicates that this region of divergent lentivirus and oncovirus SU glycoproteins forms a structurally conserved "pocket" which could accommodate a "knob"-like protrusion formed by an immunodominant region in the TM protein containing the CxxxxxC (lentiviruses) or CxxxxxxCC (C- and D-type viruses) motif. An anti-idiotypic monoclonal antibody, raised against a monoclonal antibody reacting with a sequence in the "pocket" of HIV-1 gp120, was found to bind to synthetic peptides close to the CxxxxxC motif. It is suggested that part of the SU-TM linkage mechanism for the lentiviruses and oncoviruses is a 'knob and socket' structure and that the interaction between SU and TM proteins is similar in one region for lentiviruses and C-type as well as D-type viruses. The conserved knob and socket linkage may be relevant to a mechanism for viral-cell membrane fusion that is broadly common to all of these retroviruses.


Unusual amino acid sequence of the second Ig-like domain of the feline CD4 protein.

We have cloned and sequenced the cDNA for cat CD4. The overall amino-acid sequence of cat CD4 is similar to that from the primate and rodent CD4 molecules, with a 58% identity between the cat and human sequences. Comparison to the crystal structure of human CD4 does, however, reveal unusual features in the second Ig-like domain, D2, of cat CD4. First, a reciprocal substitution between a tryptophan and a cysteine, this latter involved in an intrasheet disulfide bond of human D2, is predicted to generate an intrastrand disulfide bond, a feature rarely observed in an Ig-fold. Second, a large serine-threonine-rich insertion is found between the A and B beta strands of D2. This sequence is a potential O-linked glycosylation site, and should protrude in a region that appears flexible in human CD4. This unusual insertion could affect the interaction of cat CD4 with class II molecules, or with FIV, a feline homolog of HIV. The expression of cat CD4 in different environment, or of a mutated human CD4 carrying the cat insertion, should help in understanding the role of cat CD4 as a putative receptor for FIV, and the CD4/MHC class II interaction.


LFA-1 adhesion molecules are not involved in the early stages of HIV-1 env-mediated cell membrane fusion.

A recently developed sensitive assay to examine the early stages of HIV-1 env-mediated cell fusion is based on the redistribution of fluorescent dyes between membranes and cytoplasm of adjacent cells, monitored by fluorescence video microscopy. This assay demonstrated that membrane fusion can occur under conditions where no syncytia are formed. Fusion started earlier than syncytia formation and was not very sensitive to HIV-1 env+/CD4+ cell ratios. In the current study, this assay was used to determine the role of LFA-1 in HIV-1 env-mediated membrane fusion and syncytia formation. CD4- LFA-1- Epstein-Barr virus transformed lines from two leukocyte adhesion deficiency patients were infected with recombinant vaccinia expressing gp120/41 (HIV-IIIB), and cocultured with CD4+ subclones of the human T cell line CEM, which were generated by chemical mutagenesis and express either normal (LFA-1+), or low levels of LFA-1 (LFA-1lo). It was found that the LFA-1lo T-cell clone formed much smaller and fewer syncytia compared to the LFA-1+ subclones, but both clones fused equally well with the gp120/41 expressing LFA-1- B cells as monitored by redistribution of fluorescent dyes. Furthermore, monoclonal antibodies against the LFA-1 molecules reduced the number of syncytia formed but had no effect on membrane fusion. These findings demonstrate that the adhesion molecule LFA-1 does not play a crucial role in the early events of HIV-1 env-mediated cell membrane fusion, but may contribute to the later events leading to giant cell formation.


Sulfated polyester interactions with the CD4 molecule and with the third variable loop domain (v3) of gp120 are chemically distinct.

Sulfated polyesters (SP) that inhibit HIV infection interact with both the gp120 binding region of CD4 molecules and with the v3 domain loop of gp120 molecules (gp120/v3) but the contributions of these interactions to the inhibition of HIV env-mediated fusion are presently unclear. In order to characterize the molecular mechanisms by which SP inhibit HIV env-mediated fusion, we studied the effect of SP treatment on env-mediated fusion of CD4+ cells driven by recombinant vaccinia virus (vPE-16) and on the binding of anti-HIV MAbs to cellular gp120 or purified, rgp120. SP were more effective than neutralizing anti-gp120/v3 MAbs in inhibiting env-mediated fusion. In addition, SP interacted with the v3 loop of gp120 to inhibit the binding of the neutralizing MAb 9284 but not the binding of 9305, a neutralizing anti-gp120/v3 MAb that binds to an adjacent epitope. Because SP are polyanions, we compared the chemical properties of the SP-gp120/v3 and SP-CD4 interactions. Whereas the ability of SP to inhibit the binding of MAb 9284 and rgp120 was relatively independent of NaCl concentrations, the ability of SP to interfere with rCD4-rgp120 binding depended on the NaCl concentration and was maximal at low NaCl concentrations. In addition, the SP-gp120 interaction was found to be reversible, in contrast to the SP-rCD4 interaction which was previously shown to be relatively irreversible at low salt. These data are consistent with the notions that the interaction of SP with CD4 is primarily electrostatic, but that the interaction of SP with gp120 has complex characteristics that implicate a role for protein conformation.


Studies on the role of the V3 loop in human immunodeficiency virus type 1 envelope glycoprotein function.

Mutations within the principal neutralizing determinant (the V3 loop) of the HIV-1 surface envelope glycoprotein gp120 block or greatly reduce the ability of the HIV-1 envelope glycoprotein to induce cell fusion in CD4+ HeLa T4 cells while keeping its CD4 binding ability. However, when either cysteine or both cysteines forming the V3 disulfide bridge were mutated, the resultant glycoprotein could not mediate cell fusion, undergo proteolytic processing, or bind CD4. To investigate the role that the V3 loop plays in gp160 processing and CD4 binding, we deleted the entire V3 loop region of the HIV-1 env gene. The resultant glycoprotein could not mediate cell fusion in the HeLa T4 cell line and no proteolytic processing of gp160 or CD4 binding could be detected. To test whether any domain of the V3 loop is involved in attaining the proper envelope glycoprotein conformation required for proteolytic processing and CD4 binding, we introduced a series of deletions into the coding region of the V3 loop. Most of the residues within the V3 loop could be removed while retaining gp160 processing and CD4 binding. Our results indicate that the cysteines that form the V3 loop or the disulfide bond itself are important for proper envelope glycoprotein folding and processing. Because many of the mutants constructed in this study do not contain the type-specific neutralizing determinant of HIV-1, they may be potential reagents to bind group-specific neutralizing antibodies or to elicit a group-specific neutralizing response against HIV-1.


Analysis of the envelope region of the highly divergent HIV-2ALT isolate extends the known range of variability within the primate immunodeficiency viruses.

HIV-2ALT is a highly divergent HIV-2-related isolate that is genetically equidistant to the prototypic HIV-2 strains, defined by HIV-2ROD, and to the simian immunodeficiency viruses SIVmac and SIVsm. We have now cloned and sequenced the envelope region of HIV-2ALT, thus completing the analysis of the whole viral genome. The sequences of env and nef and of the second exons of tat and rev were compared with those of the other viruses of the HIV-2/SIVsm/SIVmac group. Despite of the high degree of variation of HIV-2ALT, functional domains of the genes are conserved. Although in env, the overall pattern of constant and variable domains is maintained, many single amino acid exchanges exist at positions previously thought to be constant in HIV-2 strains. In addition, when compared with a broader spectrum of immunodeficiency viruses, which includes SIVMND from mandrill and SIVAGM from African green monkey, HIV-2ALT Env has a high percentage of amino acid exchanges, which are unique to this strain. This underlines the separate branch of HIV-2ALT within the phylogenetic tree and makes obvious the inclusion of such divergent strains in preventive and therapeutic programs.


Infection of rhesus and cynomolgus macaques with a rapidly fatal SIV (SIVSMM/PBj) isolate from sooty mangabeys.

A variant of simian immunodeficiency virus (SIVSMM/PBj), isolated from a chronically infected pig-tailed macaque has been shown in previous studies to produce acutely fatal disease uniformly in pig-tailed macaques and in some rhesus macaques. The present study extends investigation of SIVSMM/PBj pathogenesis in rhesus and cynomolgus monkeys. Cynomolgus and rhesus macaques were found to be uniformly susceptible to infection, but as previously reported, the rhesus were found to not be uniform in their response during the acute disease. Homogenized tissues from a rhesus that died acutely from SIVSMM/PBj were passaged to 6 rhesus monkeys in an attempt to increase lethality. Five of 6 rhesus monkeys receiving intravenous inoculation of either spleen (10(3) TCID50) or lymph node (10(5) TCID50) homogenate developed acute disease; 4 died (days 8-10), 1 recovered, and one rhesus remained asymptomatic. Three of 3 cynomolgus macaques and 4 of 4 pig-tailed macaques receiving the same inoculum died acutely within 9 days. Clinical disease in macaques that died was characterized by diffuse lymphadenopathy within 5 days of inoculation and severe diarrhea beginning 1 to 3 days before death. Anorexia, lymphopenia (< 1000 cells/mm3), and mild hypoalbuminemia preceded onset of diarrhea by 24 h. Viral p27 was detected in circulation by day 6 postinfection, with all animals dying acutely having detectable serum p27 and no detectable humoral response. Acute lethality was attributed to severe metabolic acidosis (pH < 7.20) which was observed 24-48 h prior to death in the pig-tailed and cynomolgus macaques. Immunohistochemistry revealed numerous SIV antigen-positive lymphocytes and macrophages in the lymph nodes, spleen, gut-associated lymphoid tissues and gastrointestinal lamina propria. Histopathologic lesions included marked to severe hyperplasia of the T-cell-dependent areas in lymphoid tissues and diffuse nonulcerative lymphohistiocytic gastroenteritis. Surviving rhesus developed strong humoral immune responses to the major SIV proteins.


Detection of anti-human cell antibodies in sera from macaques immunized with whole inactivated virus.

More than 200 sera from macaques immunized with several different vaccine preparations were tested in various assays with cells of human and macaque origin. Only in instances where whole inactivated SIV preparations were used for immunization, were reactivities found with normal human cells, and this was the case in every instance. Such sera produced a marked clumping of several normal human cell lines and exhibited strong staining of the cell surface in FACS analysis. In the presence of SIVDeltaB670, these sera also enhanced infectivity and fusion formation. When similar tests were performed with macaque cells as targets, such phenomena were not easily discernible. Likewise, there was no trace of such activities in sera from normal animals, animals chronically infected with SIV, or in those from animals which received recombinant viral subunits as vaccines. Finally, we show that in several instances where whole inactivated virus was used as a vaccine, there is a strong correlation between the titer of anticellular activity with protection.


Analysis of HIV-1 envelope mutants and pseudotyping of replication-defective HIV-1 vectors by genetic complementation.

Infectious HIV-1 particles containing replication-defective vectors that express the hygromycin B phosphotransferase gene were generated by transient complementation in COS-1 cells. A defective vector dependent only on trans-complementation with an env gene and a small vector containing a deletion of almost all of the trans region were used to examine pseudotyping of HIV-1 by an amphotropic murine retrovirus. Although pseudotyping by the heterologous envelope glycoprotein occurred with efficiency, no pseudotyping at the RNA level was observed. Genetic complementation was used to rapidly analyze the effect of env mutations in the V3, proteolytic processing site, fusion domain, and cytoplasmic tail on viral infectivity. Mutations decreasing syncytium formation usually also lowered infectivity. However, a mutation in the cytoplasmic tail and a separate mutation adjacent to the fusion domain dramatically decreased viral particle infectivity but did not appreciably decrease envelope glycoprotein-mediated cell-to-cell fusion. These results may indicate that these regions of the transmembrane peptide are necessary for acquisition of envelope glycoprotein by budding virus particles or for virus entry.


Differential tropism of clinical HIV-1 isolates for primary monocytes and promonocytic cell lines.

Previously we demonstrated a correlation between a nonsyncytium-inducing (NSI), non-T-cell line tropic phenotype of HIV-1 isolates and the capacity to replicate in primary monocyte-derived macrophages (MDM). Here we demonstrate that these NSI, monocytotropic HIV-1 isolates lack the capacity to replicate in two promonocytic cell-lines, HL60 and U937. In contrast, most syncytium-inducing (SI) HIV-1 isolates with tropism for T-cell lines and generally non-monocytotropic were able to establish a productive infection in promonocytic cell lines. Similar differences in tropism for monocytes and promonocytic cell lines were observed with infectious molecular clones. Our results indicate that virological studies on promonocytic cell lines do not necessarily pertain to the HIV-1 infection of monocytes in vivo.


HIV-1 infection of the trophoblast cell line BeWo: a study of virus uptake.

An in vitro model has made it possible to demonstrate HIV transmission from infected lymphocytes to placental trophoblast cells via endocytosis. Upon addition to cultured trophoblast cells (BeWo), chronically HIV-infected lymphocytic cells (MOLT-4) adhered to the epithelial cells via a complex of newly induced microvilli. Though viruses were infrequently seen in the infected lymphocytic cell line, mature virions appeared promptly and profusely in the interstices between the interdigitating microvilli of the two cell types. Virions appeared to bud from the lymphocyte donor cells at the point of cell-to-cell contact and were rapidly taken up by the trophoblast cells via an endocytic mechanism involving coated pits, endosomes, and lysosomes. Electron microscopic observations suggest that HIV may later escape into the trophoblast cytoplasm by fusing with the endosome membrane or by lysing the lysosome membrane. Coincubation for 1 h was sufficient to establish HIV infection in the trophoblast cell line. Four weeks after thoroughly washing out the donor lymphocytic cells, HIV RNA was demonstrated in clusters of BeWo cells by in situ hybridization, and p24 antigen was localized with immunocytochemistry. Soluble CD4 did not block infection as measured by p24 ELISA. The HIV infection was productive and chronic as demonstrated by cocultivating the BeWo cells with indicator lymphocytes 4 weeks after the initial infection. This study, demonstrating a mechanism of HIV transmission, expands upon previous observations that trophoblast cell lines lacking the CD4 viral receptor can nevertheless be infected by HIV and can support productive infection.


Modulation of glucocorticoid binding to rat liver cytosol receptor by lipid-soluble extracts from the serum of AIDS patients.

The total liposoluble extract of sera from AIDS patients, IVC1 and IVD stages, containing cortisol and free fatty acids (FFA) inhibited [3H]dexamethasone binding to a lesser extent than did the same quantity of total liposoluble extract of sera from healthy men. FFA isolated from extracts of AIDS sera by Sephadex LH20 chromatography had less effect on [3H]dexamethasone binding to rat liver glucocorticoid receptor than those extracted from sera of healthy men. These results suggest the presence in sera of AIDS patients of a liposoluble substance which could be limiting the inhibitory effect of FFA on [3H]dexamethasone binding to glucocorticoid receptor by inducing a conformational change in glucocorticoid receptor that could alter the biological action of glucocorticoids. The pathological consequence could be the apparent contradiction of high cortisolemia and clinical symptoms of adrenal insufficiency that have been observed in AIDS patients.


Dendritic cells from patients with tropical spastic paraparesis are infected with HTLV-1 and stimulate autologous lymphocyte proliferation.

Dendritic cells (DC), important antigen-presenting cells for recruiting T cells into immune responses, are susceptible to infection with HIV-1 and this can cause either stimulatory or suppressive effects on T cells. We examined another human retrovirus, HTLV-1, to determine whether DC were infected and caused any changes in T-cell function. Patients infected with HTLV-1 who have tropical spastic paraparesis (TSP) show high 'spontaneous' lymphocyte proliferation. We studied the basis for this by analyzing the interactions in vitro between lymphocytes and antigen-presenting cells and compared cells taken from HTLV-1-positive TSP patients with those taken from HTLV-1-positive healthy carriers and HTLV-1-negative family members. In HTLV-1-positive individuals, 0.4-5.1% of the DC were infected with HTLV-1 as determined by in situ hybridisation. In TSP patients, depletion of DC and purification of T cells abolished 'spontaneous' lymphocyte proliferation. Reinstating the DC, but not B cells or macrophages, restored proliferation, an effect that was blocked by antibodies either to class II major histocompatibility antigens or to HTLV-1 itself. Thus, presentation of HTLV-1 antigens by infected DC to autologous T cells could result in the abnormal T-cell proliferation and cause the inflammatory reaction leading to tissue damage in TSP. We also speculate that persistent infection of DC with HTLV-1 and consequent continuous stimulation of T cells might be instrumental in the development of HTLV-1-mediated T-cell leukemia.


Dysregulation of adult T-cell leukemia-derived factor (ADF)/thioredoxin in HIV infection: loss of ADF high-producer cells in lymphoid tissues of AIDS patients.

Adult T-cell leukemia (ATL)-derived factor (ADF) is a multifunctional protein homologous to thioredoxin (TRX) with co-cytokine and thiol-dependent reducing activities. ADF/thioredoxin production is enhanced in T cells transformed by HTLV-I. We have examined the effect of HIV-1 infection on ADF/TRX expression using specific antibody against ADF/TRX. Lymph nodes from 5 AIDS and 1 AIDS-related complex (ARC) patients were examined. As a control, 8 HIV noninfected lymph nodes, including 3 cases with hyperplasia, were also examined. Immunohistopathological studies using normal HIV noninfected lymph nodes showed that ADF/TRX high-producer (ADFh) cells were macrophages and cells with dendritic morphology in the paracortical area. Abundant ADFh cells were observed in HIV noninfected hyperplastic lymph nodes. The number of ADFh cells was low in hyperplastic lymph nodes from an ARC patient. All of the lymph nodes of 5 AIDS cases were atrophic and the number of ADFh cells were extremely low. To verify these histochemical studies, we examined the effect of in vitro HIV infection on ADF/TRX expression in HTLV-I (+) T-cell lines. Western blot analysis showed that a reduction of ADF/TRX in HIV-1-infected SKT-1B and MT-2 cells, and the reduction inversely correlated with p24 antigen level. On the basis of the above in vivo and in vitro findings, we imply that the levels of ADF/TRX were down-regulated by HIV-1 infection and that the down-regulation may play a role for pathophysiology of HIV-infected individuals.


Characterization of oxyphenarsine as a potential antiviral agent for AIDS.

The historical antisyphilis drug oxyphenarsine has been tested for antiviral activity and for cytotoxicity to characterize it as a potential therapy for treatment of HIV infections. These data show that the compound demonstrates marginal antiviral activity against the HTLV-IIIB strain of HIV-1, two clinical isolates of HIV-1 (one sensitive to AZT and one resistant), and the MS strain of HIV-2. However, treatment with concentrations of oxyphenarsine showing optimal anti-HIV activity resulted in significant cytotoxicity. The drug's selectivity index was not significantly improved when tested against H9 cells chronically infected with the HTLV-IIIB strain of HIV-1. Thus, despite a previous report suggesting significant antiviral activity and low cytotoxicity for oxyphenarsine, the data presented here do not provide support for further development of this drug as an anti-HIV agent.


Rapid complementation assay for anti-HIV-1 drug screening and analysis of envelope protein function.

A complementation assay is described that can be used with relative safety to quantitate rapidly inhibitory effects of potential anti-HIV-1 drugs on virtually any stage of the HIV-1 life cycle by measurements of chloramphenicol acetyltransferase (CAT) activity. Of particular interest is that this system is also capable of detecting inhibition of the viral trans-activator Rev, an important potential target for drug intervention. Other applications of the system may include studies to identify domains of the envelope glycoprotein that determine infectivity and tropism or that define epitopes recognized by neutralization antibodies.


Rapid and simple characterization of in vivo HIV-1 sequences using solid-phase direct sequencing.

Solid-phase direct sequencing was used to obtain in vivo sequence data of polymerase chain reaction (PCR)-amplified HIV-1 p25/p7 gene segments. The solid-phase sequencing method was compared to double-strand sequencing of preparative gel electrophoresis-purified amplification products and found to give more consistent results. Lysates of cells were compared to purified DNA as PCR template. HIV-1 sequences were as well amplified from lysates as from purified DNA and 7,780 bp of sequence from 41 samples were produced by direct sequencing. Sequence analysis revealed common sequence motifs relating the sequence to the Euroamerican and African groups of sequences previously described. The results indicate that many viruses of diverse origin circulate in Finland, although the majority seems to be of Euroamerican type. Solid-phase direct sequencing may provide a valuable tool for both epidemiological and pathogenic studies of in vivo HIV-1 infections.


Regulations vs. ideals: a case history of a hospice closure.

The cost of health care and health insurance and the increasing number of Americans without access to basic health services has become a primary issue in today's society. Leading politicians, economists, planners, and private individuals recognize the essential need to re-design the system and provide coverage to all Americans. However, the history of programs strangling in the red tape created by inflexible regulatory efforts to set standards, monitor performance, and control costs, thereby denying access to individuals they were specifically designed to serve, points to the need for an equally new approach to planning such a system. The authors have attempted to illustrate, through the case history of the closure of a hospice serving a poor socioeconomic area of New York City, the need for government regulators, program planners, and caregivers to recognize and define common goals and develop flexible and cooperative working relationships.


The last few days.

In the dying patient, coma is preceded by either progressive sedation or the development of the organic brain syndrome of delirium. More than one-third of dying patients experience some difficulties during the last 48 hours of life with noisy and moist breathing, pain, and agitation and restlessness the most common. The great majority of these terminal symptoms can be managed by reassurance or drug intervention. Sublingual lorazepam and continuous subcutaneous infusion of midazolam can be effective in controlling terminal restlessness.


Hospice research: the importance of program participation.

Hospice research is needed in order to understand the complex phenomena of holistic care for terminally ill persons and their families. Hospice program participation is key to future hospice research efforts. The purpose of this article is to encourage hospice programs to participate in hospice research. The discussion includes why research is done, who undertakes a research project, the role of institutional review boards in assuring rights of human subjects and potential strategies for recruitment of research subjects. The authors use their experiences with conducting hospice research to illustrate potential recruitment strategies.


Family assessment and its relation to hospice care.

It is proposed that a family system evaluation be added to the initial medical and social history used during a hospice assessment. The family evaluation should assess the family through a functional/dysfunctional framework in addition to assessing the role structure of each of its members. This additional data can offer insight into the internal workings of the family while adding important information as to the compliance level of the family in accepting hospice and the services that hospice has to offer. This may assist in not only the quality of service implementation but in assisting hospice personnel in lessening their potential for stress and burnout as well.


Acupressure wrist bands to relieve nausea and vomiting in hospice patients: do they work?

This study assessed the effects of acupressure wrist bands on the nausea and vomiting of terminally ill patients. Using a single subject experimental design, six hospice patients were exposed to three conditions: An acupressure wrist band; A placebo wrist band; A no wrist band condition. Patients and their caregivers rated nausea and vomiting during the treatment. Despite some difficulty obtaining complete data, the results of this preliminary test indicate that acupressure wrist bands were not effective in reducing nausea and vomiting in this small sample of hospice patients.


The hospice volunteer: a person of hospitality.

Volunteers are integral members of the hospice interdisciplinary team. They are distinguished from other members of the team only by role, not by expectation. The distinction is not between "volunteer" and "professional," because every team member is to be professional in the best sense of that word. If a distinction is to be made, it is that some hospice staff members are salaried while others donate their services. Volunteer staff members are expected to be as responsible and accountable as every other member of the team. ALL staff members must realize the importance of taking care of personal needs in order to be able to care for others. Even though the following article deals primarily with the volunteer hospice staff member, the points outlined can just as easily be applied to the salaried staff member.


Functional morphology of the enteric nervous system with special reference to large mammals.

This short review reports the latest insights into the structural organization of the enteric nervous system, with special emphasis on the intrinsic innervation of the intestinal tract of large omnivorous mammals such as the pig. Using various techniques, including lesion experiments, morphological and neurochemical features of distinct neuronal populations as well as the direction of the axonal processes within the different nerve networks could be revealed. Special attention was paid to the considerable species differences in this respect between large omnivorous animals and humans on the one hand and small laboratory animals on the other hand.


Histogenesis, structure and relationships of interstitial cells of Cajal (ICC): from morphology to functional interpretation.

Interstitial cells of Cajal (ICC) have been found exclusively in gut muscle coat, occupying an interstitial position between nerve endings (NE) and smooth muscle cells (SMC). Light microscope stainings of ICC are aspecific and useful only for evidentiating cell body and ramifications strictly intermingled with SMC and nerve fibers. Transmission electron microscope investigation, on the contrary, permits unequivocable identification and detailed description of ICC cytology. The ultrastructural findings have led to consider ICC as a new cell type, with a specific cytology, highly smooth muscle-like. Specialized ICC relationships with surrounding cells have been found, suggesting the existence of an anatomical unit made up of three closely interconnected elements: the NE-ICC-SMC units. The time of this unit appearance and the steps of its cell types cytodifferentiation from foetal to adult life differ according each gut level. A region-specific ICC distribution inside the gut muscle coat and peculiar organizations of ICC surrounding connective tissue have been observed. On these morphological bases an ICC pacemaking role has been suggested. Recordings of spontaneously generated slow waves from some ICC seemed to confirm this role. According to this hypothesis, smooth muscle contraction should be dependent on ICC function and smooth muscle relaxation on inhibitory nerves release. Further morpho-functional investigations and correlations of obtained data are still necessary in order to better clarify the ICC role and its influence or dependence on both nerve and muscle tissues inside each gut level. The identification of the neurotransmitters contained in the NE contacting ICC and/or SMC needs to be pursued.


Perceptions of the most helpful nursing behaviors in a home-care hospice setting: caregivers and nurses.

The purpose of this study was to determine those nursing behaviors perceived as most helpful and least helpful by primary caregivers and by hospice nurses in a home-care hospice setting. A Q-sort of 60 nursing behaviors ranked from most to least helpful was completed by 20 caregivers, during the bereavement period and by five hospice nurses, who were currently employed by the hospice. These nursing behaviors were categorized as: Nursing behaviors related to the patient's physical needs; nursing behaviors related to the patient's psychosocial needs; and nursing behaviors related to the psychosocial needs of the caregivers.


Incidence and clinical study of ectopic erythropoiesis in adult patients with thalassemia intermedia.

We carried out total body computerized tomography (CT) studies and examined the retrospective clinical data of 29 adult patients with thalassemia intermedia (TI) to evaluate the incidence, features and pathogenesis of ectopic erythropoiesis (EE), located chiefly at the paravertebral gutters in the thorax, was present in 65.5% of the patients; 15% of them had severe clinical complications. We found a clear relationship between EE development and early presentation age of thalassemia, splenectomy and the presence of 100% fetal hemoglobin. The frequent occurrence of EE suggests that CT screening of patients with thalassemia intermedia should be mandatory. We also recommend radiotherapy as a preventive measure for the clinical complications of thalassemic patients with EE.


[Acromegalic cardiopathy: a morphofunctional study with color-Doppler echocardiography].

We used color-Doppler echocardiography in an investigation of cardiac morphology and function to verify the cardiac anatomic and functional changes in acromegalic patients with or without hypertension and hyperlipemic states. Fifteen patients with growth hormone-secreting pituitary adenoma (mean age: 47.9 years) and 15 healthy control subjects were studied. We measured serum growth hormone (GH), somatomedin-C, cholesterol, triglyceride levels and carried out echocardiographic studies of the following cardiac morpho-functional parameters: left ventricular diameter, volume, mass and wall systolic stress. Serum GH and somatomedin-C levels were significantly higher in acromegalic patients than in controls (p < 0.001 and p < 0.001 respectively). Echocardiography evidenced increased left ventricular mass (60% of the acromegalic patients; p < 0.05) and increased wall systolic stress (53.3%; p < 0.05). Color-Doppler analysis evidenced abnormal diastolic function in 8 acromegalic patients (p < 0.001). We thus conclude that the most characteristic feature of acromegalic heart disease is left ventricular involvement, diastolic dysfunction, increased left ventricular mass or wall systolic stress. The pathogenesis is most probably multifactorial: essential hypertension, associated with slow and progressive evolution of heart disease, appears to be a determining factor.


[Diabetic nephropathy and arterial hypertension: the physiopathological aspects and antihypertensive treatment].

The purpose of our review is to delineate the pathogenic steps linking arterial hypertension in diabetes to diabetic nephropathy. The results of recent studies suggest that arterial hypertension in diabetes might lay a decisive pathogenetic role in the evolution of diabetic nephropathy: the existence of a higher ratio of erythrocytic Na/Li counter-transport in nephropathic diabetics as well as higher pressure values in the parents of diabetics who develop nephropathy indicates that hypertension may be casually related to renal complications. Diabetes-associated hypertension involves the modification of two important pressure- regulation factors: 1. an alteration in extracellular volume and increased renal absorption of sodium which leads to an expanded pool; 2. increased cardiovascular reactivity to norepinephrine and angiotensin II, an effect which might be related to increased intracellular calcium. Hyperfiltration seems to be present at the onset of diabetes, and arterial hypertension increases the transglomerular pressure gradient which is thought to play an important role in the pathogenesis of kidney damage. Antihypertensive drugs such as ACE-inhibitors and calcium channel blockers tend to protect the regulation of renal function. This could be explained by the fact that ACE-inhibitors suppress the trophic effects of angiotensin II on the nephron, while calcium channel blockers might interfere with intracellular processes involved in cell hypertrophy that require the interaction of calcium ions. In the management of diabetes prevention of diabetic nephropathy requires early and careful correction of diabetes-associated hypertension. We discuss the major groups of antihypertensive drugs, their metabolic side-effects and intrarenal induced hemodynamic changes.


[The immunopathogenesis of hepatitis B].

Knowledge of hepatitis B immunopathogenesis has greatly improved in the last few years thanks to the development of new methods of lymphocyte culture and the introduction of molecular techniques in the study of the cell-mediated antiviral immune responses. Some of the immune mechanisms likely responsible for liver cell injury and viral clearance during hepatitis B have recently been characterized. By using synthetic peptides and high efficiency recombinant expression vectors. HLA class I restricted cytotoxic T cells specifically able to recognize the nucleocapsid antigen of the hepatitis B virus (HBV) have been isolated from the blood of patients with acute self-limited hepatitis B. The observation that this cytotoxic response is lacking or very weak in chronic patients who do not succeed in clearing the virus suggests a major role for cytotoxic T cells in terminating virus infection. Similar behaviour is shown by HLA class II restricted CD4+ T cells which express much stronger levels of response to HBV nucleocapsid antigens in acute than in chronic HBV infection. Whether these defective responses in chronic patients are due to an actual lesion of the host's immune system or to viral mutations affecting immune surveillance and thereby allowing virus escape, still remain open issues. A definitive answer to these questions will, we hope, provide the appropriate tools to devise effective immune therapies against chronic HBV infection.


[Chronic eosinophilic pulmonitis with eosinophilic pleurisy. A report on 2 clinical cases seen by the authors].

We discuss the cases of two patients affected with chronic eosinophilic pneumonia (CEP) pleurisy and eosinophilia in pleural effusion, not previously mentioned in the literature, to point out their peculiarity, to consider differential diagnosis and the effect of steroid therapy. Both patients, a 57-year-old man and a 55-year-old woman, were atopic: they had been suffering from allergic rhinitis and asthma for several years when they suffered sudden onset of cough, dyspnea and thoracic pain. This symptomatology persisted for more than 6 weeks. Chest radiography highlighted pulmonary infiltrates, not fixed in the first case, fixed in the second. The laboratory features revealed eosinophilia in peripheral blood and in pleural effusion. These data conformed to the criteria suggested by Jederlinic et al. for the diagnosis of chronic eosinophilic pneumonia. Tuberculosis had been present in the remote history of the second case; the repeated research for mycobacteria was negative, and no improvement was seen after antitubercular chemotherapy for one month. We excluded the diagnosis of allergic bronchopulmonary aspergillosis because of the absence of both precipitating antibodies against Aspergillus fumigatus and bronchiectasis. Neither vasculitis nor autoantibodies were found; possible drug-related correlations were excluded; culture data and serological researches for infections were negative in both cases; no involvement of other districts correlated to hypereosinophilia was evidenced. Clinical and radiological remission was obtained in both cases after steroid therapy for a month at the dosage of 1-2 mg/kg daily. No clinical recurrence was seen during a follow-up period of 6 months. Pleural effusion has already been reported in patients with CEP, while we have not found any references to pleural fluid eosinophilia in this disease; this finding has instead been already reported in patients affected with acute eosinophilic pneumonia or hypereosinophilic syndrome.


[Thrombosis of the superior sagittal sinus and ulcerative colitis. A case report].

We describe a rare case of superior sagittal sinus thrombosis in a young man (26 years) with undiagnosed ulcerative colitis. The patient was hospitalized with headache and paresis of the right arm and leg. he had had rectal bleeding and diarrhea for the previous 4 weeks. Despite the fact that heparin therapy is still considered controversial, we successfully treated our patient with low doses of sub-cutaneous heparin. He did not suffer any side-effect.


The use of microcomputer-based psychomotor tests for the evaluation of benzodiazepine effects on human performance: a review with emphasis on temazepam.

1. The literature relating to the effects of benzodiazepines in general, and temazepam in particular, on human psychomotor performance as assessed using microcomputer-based testing batteries is surveyed. 2. The adverse effects of central nervous system depressants on performance is an important mediocolegal issue and frequently comes into question in on-the-road and on-the-job accidents. The use of microcomputer-based testing batteries allows for performance evaluation both in the laboratory and at-the-scene, as well as providing the opportunity to model a large number of different behaviours required in routine yet complex psychomotor tasks. 3. The conclusions in general are: (1) The benzodiazepines as a class of drugs impair both cognitive and motor performance. These effects are often subtle when low doses are involved or when testing occurs the morning following evening administration of the medication. (2) No single psychomotor task adequately simulates complex daily tasks such as automobile driving. A battery of tests that evaluates a number of the components of such tasks is necessary to determine adequately the full range of effects of these medications.


Intracholecystic hemorrhage: an atypical complication after liver needle biopsy.

The authors report an unusual case of intracholecystic hemorrhage related to liver biopsy in a 23-year-old man. Echography and computed tomography evidenced changes in density within the gallbladder which were probably caused by hemorrhagic discharge. Although the mechanism by which liver biopsy induced intracholecystic hemorrhage is unclear, the authors believe that this iatrogenic complication was probably the result of microlesions of the gallbladder wall caused by needle puncture: the lesions extended into the submucosa and provoked slow hematic leakage. The pain syndrome began 48 hours after biopsy. The peculiarity of this case report was confirmed by the fact that no bile was aspirated, no choleperitoneum was found, and no gallbladder tissue was detected in the sample. The authors conclude by recommending clinical and echographic control following liver biopsy.


New models of focal cerebral ischaemia.

1. Studies in animal models of stroke have provided an invaluable contribution to our current understanding of the pathogenesis of cerebral ischaemia. The strengths of stroke research in animals are: 1) the ability to control the severity, duration, location and cause of the ischaemia, variables which confound interpretation of human stroke data; 2) co-existent disease states and variations in cerebrovascular anatomy are avoided; and 3) physiological parameters such as blood pressure, blood gases, temperature and plasma glucose (all of which influence the magnitude of the ischaemic lesion) can be closely monitored and controlled. Taking all these things on board, it is possible to induce a consistent focal ischaemic lesion in animal models of stroke (e.g. the permanent occlusion of the middle cerebral artery (MCA) in the rat). This has resulted in the wide use of animal models for assessment of anti-ischaemic drug efficacy as well as for research into the pathophysiological sequelae of stroke. 2. Traditionally focal ischaemia models involved permanent occlusion of a major cerebral artery such as the MCA. However, since vessel occlusion is seldom permanent in human stroke more recent developments have incorporated reperfusion (following ischaemia) into the design of the animal model. This has been achieved by reversible occlusion of cerebral vessels using 1) intraluminal filaments; 2) microclips; 3) the abluminal application of potent and prolonged vasoconstrictors; or 4) the introduction of emboli into the cerebral circulation.(ABSTRACT TRUNCATED AT 250 WORDS)


Determination of the relative bioavailability of salbutamol to the lung following inhalation.

1. The urinary excretion of salbutamol and its sulphate metabolite was measured following oral (4 mg) and inhaled (4 x 100 micrograms) administration of salbutamol. 2. Total urinary recovery of salbutamol and its sulphate conjugate indicated a mean (s.d.) relative bioavailability of 92.2 (24.8) % following inhalation compared with oral administration. 3. The mean (s.d.) elimination half-lives of salbutamol and its sulphate conjugate were 5.7 (1.4) and 4.1 (2.1) h, respectively, after oral administration and following inhalation they were 6.1 (2.1) and 5.1 (1.0) h, respectively. 4. Following oral and inhaled administration it was found that in the first 30 min the mean (s.d.) percentage of the dose excreted in the urine as unchanged salbutamol was 0.18 (0.14) and 2.06 (0.80) %, respectively (P < 0.01). The drug content of a urine sample taken 30 min after inhalation is, therefore, considered to be representative of the amount of drug delivered to the lungs. It is proposed that this method can be used to evaluate the relative bioavailability of salbutamol to the lung following inhalation by different techniques and devices.


Ethanol kinetics: extent of error in back extrapolation procedures.

1. Plasma ethanol concentrations were measured in 24 male volunteers for 9 h after a single oral dose of 710 mg kg-1. 2. The rate of decline of the plasma ethanol concentration (k0; mean +/- s.d.), was 186 +/- 26 mg l-1 h-1. 3. In each individual, three elimination rates were used to back-extrapolate plasma ethanol concentrations over 3 and 5 h periods from observed values at 4 h and 6 h post-dosing assuming zero-order kinetics. The extrapolated values were then compared with the observed concentrations. 4. Using the mean k0 values for the subjects the mean error in back extrapolation was small but highly variable. The variability in the error increased with the length of the extrapolation period. 5. When a k0 value of 150 mg l-1 h-1 (a value often cited as a population mean) was used for back extrapolation this resulted in significant under-estimation of actual values whereas the use of a k0 value of 238 mg l-1 h-1 (the highest value observed in the present study) resulted in significant over-estimation of actual values. 6. These results indicate that because the kinetics of ethanol are associated with substantial inter-subject variability the use of a single slope value to back calculate blood concentrations can give rise to considerable error.


Histamine N-methyl transferase: inhibition by drugs.

1. Histamine N-methyl transferase activity was measured in samples of human liver, brain, kidney, lung and intestinal mucosa. The mean (+/- s.d.) rate (nmol min-1 mg-1 protein) of histamine N-methylation was 1.78 +/- 0.59 (liver, n = 60), 1.15 +/- 0.38 (renal cortex, n = 8), 0.79 +/- 0.14 (renal medulla, n = 8), 0.35 +/- 0.08 (lung, n = 20), 0.47 +/- 0.18 (human intestine, n = 30) and 0.29 +/- 0.14 (brain, n = 13). 2. Inhibition of histamine N-methyl transferase by 15 drugs was investigated in human liver. The IC50 for the various drugs ranged over three orders of magnitude; chloroquine was the most potent inhibitor. 3. The average IC50 values for chloroquine were 12.6, 22.0, 19.0, 21.6 microM in liver, renal cortex, brain and colon, respectively. These values are lower than the Michaelis-Menten constant for histamine N-methyltransferase in liver (43.8 microM) and kidney (45.5 microM). Chloroquine carried a mixed non-competitive inhibition of hepatic histamine N-methyl transferase. Some side-effects of chloroquine may be explained by inhibition of histamine N-methyl transferase.


The influence of posture on the pharmacokinetics of orally administered nifedipine.

1. Nifedipine (20 mg as capsules) and soluble paracetamol (1 g) were co-administered to eight healthy young volunteers on three separate occasions, following which in random order they stood, lay on their left side or lay on their right side for 4 h. 2. The time to maximum plasma concentration of paracetamol was significantly lower when standing or lying on the right side compared with recumbent left, indicating more rapid gastric emptying. 3. The times to maximum plasma concentrations of nifedipine and its metabolite produced at first pass were reduced when standing or lying on the right side. These postures were associated with significantly higher peak plasma concentrations and AUC values of nifedipine but not of its nitropyridine metabolite. 4. The increase in heart rate following nifedipine administration was significantly greater when lying on the right side compared with the left. 5. The data are consistent with transient saturation of first pass metabolism of nifedipine with postures which favour rapid gastric emptying. The results demonstrate the importance of defining the precise posture in studies in which pharmacokinetic and pharmacodynamic measurements are made on drugs which are absorbed rapidly and are subject to presystemic elimination.


The effect of a prostaglandin DP-receptor partial agonist (192C86) on platelet aggregation and the cardiovascular system in healthy volunteers.

1. PGD2 (DP)-receptors mediate inhibition of platelet aggregation and vasodilatation. If receptor reserve were greater on platelets it might be possible to separate these effects. To determine whether such a difference in receptor reserve exists, we have examined the effects of a highly selective DP-receptor partial agonist 192C86 on platelet aggregation and the cardiovascular system in healthy volunteers. 2. Using an open, dose-escalating study design, four male volunteers received constant rate intravenous infusions of 192C86 for up to 60 min. Ex vivo platelet aggregation to ADP and collagen in platelet-rich plasma (PRP) and whole blood (WB) was studied at baseline, after 15, 30 and 60 min of each infusion and at 180 min post-infusion. Heart rate (HR), systolic and diastolic (DBP) blood pressure were measured at frequent intervals. Adverse experiences were monitored by checklist. Facial flushing was assessed by the volunteer using a visual analogue scale, by an observer using a numerical scale and by full-face colour photographs. Blood was taken for assay of plasma 192C86 concentrations by radio-immunoassay (r.i.a.). 3. 192C86 (0.007-0.058 micrograms kg-1 min-1) inhibited platelet aggregation to ADP and collagen both in PRP and WB in a dose-dependent manner. However, this was always accompanied by a decrease in DBP, increase in HR and facial flushing. Plasma concentrations of 192C86 were at or below the limits of sensitivity of the r.i.a. (0.5 ng ml-1). 4. The highest infusion rate was stopped after 20 min due to symptomatic hypotension on standing.(ABSTRACT TRUNCATED AT 250 WORDS)


Ginkgo biloba for cerebral insufficiency.

1. By means of a critical review we tried to establish whether there is evidence from controlled trials in humans on the efficacy of Ginkgo biloba extracts in cerebral insufficiency. 2. The methodological quality of 40 trials on Ginkgo and cerebral insufficiency was assessed using a list of predefined criteria of good methodology, and the outcome of the trials was interpreted in relation to their quality. A comparison of the quality was made with trials of co-dergocrine, which is registered for the same indication. 3. There were eight well performed trials out of a total of 40. Shortcomings were limited numbers of patients included, and incomplete description of randomization procedures, patient characteristics, effect measurement and data presentation. In no trial was double-blindness checked. Virtually all trials reported positive results, in most trials the dosage was 120 mg Ginkgo extract a day, given for at least 4-6 weeks. For the best trials, there were no marked differences in the quality of the evidence of the efficacy of Ginkgo in cerebral insufficiency compared with co-dergocrine. The results of the review may be complicated by a combination of publication bias and other biases, because there were no negative results reported in many trials of low methodological quality. 4. Positive results have been reported for Ginkgo biloba extracts in the treatment of cerebral insufficiency. The clinical evidence is similar to that of a registered product which is prescribed for the same indication. However, further studies should be conducted for a more detailed assessment of the efficacy.


Perturbation of paracetamol urinary metabolic ratios by urine flow rate.

The effects of high and low urine flow rates on the urinary metabolic ratios for paracetamol glucuronidation, sulphation and oxidation were determined at steady-state in seven healthy young adult volunteers. Metabolic partial clearances were unaffected by urine flow rate, but individual paracetamol metabolic ratios varied 2.5- to 3.2-fold over a 7.4-fold range of urine flow rates (0.81-6.00 ml min-1). The change in metabolic ratios was due entirely to a 2.5-fold change in renal clearance of unchanged paracetamol. These data emphasise the limitations of the metabolic ratio as a measure of intrinsic clearance for compounds which undergo some degree of tubular reabsorption.


Effect of alacepril on blood pressure and neurohumoral factors at rest and during dynamic exercise in patients with essential hypertension.

We assessed blood pressure and neurohumoral factors at rest and during exercise in 10 patients with essential hypertension before and after treatment with the new angiotensin converting enzyme inhibitor, alacepril (25-50 mg day-1). Alacepril significantly lowered mean blood pressure at rest and at the same exercise load as before treatment without affecting heart rate response. The response of plasma renin activity, plasma aldosterone, and plasma adrenaline were not changed by alacepril, but increase of plasma angiotensin II and plasma noradrenaline during exercise were significantly attenuated after alacepril treatment (ANOVA, P = 0.04, both). The change in mean blood pressure during exercise was positively correlated with the decrease in plasma angiotensin II (r = 0.65, P < 0.05). These results demonstrated that alacepril was effective in essential hypertension both at rest and during exercise, suggesting that the antihypertensive effect during exercise might be related to the decrease in pressor hormones, especially in plasma angiotensin II.


Effect of angiotensin converting enzyme inhibitors on erythropoietin concentrations in healthy volunteers.

The possibility that the ACE inhibitors, enalapril and captopril, may decrease plasma EPO concentrations was studied in a single-blind, cross-over study in 10 healthy volunteers. Plasma EPO concentrations, haemoglobin concentration, red blood cell count, plasma creatinine concentration and mean arterial pressure were measured at baseline and after 28 days treatment with both ACE inhibitors. A significant fall in mean plasma EPO concentration occurred with both ACE inhibitors and returned to baseline after stopping the drugs. It is likely that ACE inhibitors decrease EPO formation, by inhibition of angiotensin-II production. This effect could be important in patients with renal failure, renal transplantation or other chronic conditions with an associated anaemia. Haematological parameters should be monitored in such patients when they are treated with an ACE inhibitor.


Duchenne muscular dystrophy.

Advances in the understanding of the genetic basis for Duchenne muscular dystrophy over the past 4 years has led to the quick application of molecular diagnostics. More recently, attention has turned towards acquiring a better understanding of dystrophin biochemistry and the pathophysiologic consequences of dystrophin deficiency.


Muscle fiber types and function.

A major recent advance in the field of muscle fiber types has been the discovery that myogenic factors regulate fiber phenotypic properties. Myogenic influences occur in limb and trunk (somitic) muscle, but are particularly strong in jaw-closing muscles and extraocular muscles that express some unique myofibrillar proteins. In somitic muscles, a variant of fast fiber has been discovered, making four types of fibers: I, IIA, IIX, and IIB. These fibers express different isoforms of myofibrillar and other proteins. The speed and power of the four types of fibers are distinct and are controlled principally by their myosin heavy chains, which modulate the two regulatory steps in the crossbridge cycle, one controlling the rate of development of force, the other controlling the maximal velocity of shortening. Fast fibers have a higher threshold for Ca(2+)-activated force and a steeper force-pCa relation than do slow fibers. This difference is largely attributable to the cooperativity in the attachment of crossbridges and to the difference in Ca2+ binding capacity of their troponin C. Ca2+ initiates force development in muscle by increasing the rate of attachment of crossbridges. The phosphorylation of myosin light chain enhances this action. This effect of phosphorylation underlies the phenomenon of posttetanic potentiation of the isometric twitch in fast fibers.


Clinical applications of muscle enzymes and proteins.

Total creatine kinase measurement in serum has remained the best overall marker for detection and monitoring of skeletal muscle diseases, despite that different human tissues exhibit varying distributions of cytoplasmic and mitochondrial isoenzymes of creatine kinase. Acute myocardial infarction aside, increases in total serum creatine kinase, as reflected by the MM isoenzyme, are most commonly caused by injury or diseases to striated muscle. Enzyme markers of skeletal muscle injury that have been previously used (eg, aldolase, enolase, aspartate aminotransferase, and lactate dehydrogenase isoenzyme 5) are not as specific as creatine kinase and have limited clinical utility. However, new enzyme and protein markers are currently being investigated, eg, troponin and carbonic anhydrase III, which are more specific than creatine kinase toward particular tissues. Moreover, measurement of creatine kinase isoforms may provide information about whether muscle turnover is acute or chronic.


Raynaud's phenomenon.

Raynaud's phenomenon occurs in about 5% of the adult population, and most individuals do not seek medical attention for the condition. In symptomatic patients with Raynaud's phenomenon, it is useful to categorize the condition as primary or secondary. In addition to providing a framework for epidemiologic and therapeutic protocols, such classification may reflect basic pathophysiologic differences. Occupation-related Raynaud's phenomenon has been recognized recently as a major cause of lost wages and productivity. Neurogenic and "local fault" hypotheses to explain primary Raynaud's phenomenon are still being studied. In secondary Raynaud's phenomenon, obliterative arteriopathy and the role of endothelial-derived products have been the focus of intense research interest. Under some circumstances, the combination of nailfold capillary microscopy and autoantibody analysis can identify patients with primary Raynaud's phenomenon that is likely to evolve into a secondary form of Raynaud's phenomenon. Although information from this type of analysis may be overinterpreted, the prognostic yield is highest for patients destined to develop systemic sclerosis-related disorders. Newer vasodilating agents and antithrombotic drugs may offer benefit for patients with both primary and secondary Raynaud's phenomenon.


Overlapping syndromes, undifferentiated connective tissue disease, and other fibrosing conditions.

Many patients presenting with symptoms suggestive of a connective tissue disease do not fulfill criteria for a specific connective tissue disease at initial presentation. Some of these patients with undifferentiated connective tissue disease eventually develop a specific connective tissue disease. Recently, a large cohort of 213 patients from different centers with undifferentiated connective tissue disease of early onset were enrolled in a prospective protocoled study. Baseline characteristics, including antinuclear antibody profiles, were reported. The aim of this study was to define predictors for the development of specific organ-system involvement and connective tissue diseases in early undifferentiated connective tissue disease. Many patients show overlapping features of two or more connective tissue diseases. The presence of autoantibodies to U1-ribonucleoproteins has been associated with a particular overlap syndrome, mixed connective tissue disease. Most anti-U1-ribonucleoprotein-positive patients with undifferentiated connective tissue disease at presentation appear to develop mixed connective tissue disease over the course of disease. Although levels of anti-U1-ribonucleoprotein do not seem to be related to disease activity, this association suggests a pathogenetic relationship between anti-U1-ribonucleoprotein and mixed connective tissue disease. Genetic studies have shown that patients with antibodies against the 70-kD component of U1-ribonucleoprotein share a common epitope within the groove of their DR molecules at antigen-binding region, pointing to a particular antigen involved in the induction of these antibodies that may be relevant in the etiopathogenesis of associated disease.