Determination of femtomole/milliliter concentrations of enprostil acid in human plasma using high-performance liquid chromatography-laser-induced fluorescence detection

This paper describes the use of multiple-column high-performance liquid chromatography (HPLC) combined with laser-induced fluorescence for the determination of femtomole/milliliter concentrations of enprostil acid, a prostaglandin analogue, in human plasma. The drug is isolated from plasma by phenyl solid-phase extraction and fluorescently labeled at its carboxyl functional group with a large excess of 2-bromoacetyl-6-methoxynaphthalene. A multi-column method using both normal- and reversed-phase chromatography is necessary to separate the labeled drug from the unreacted reagent. Post-column dilution of the mobile phase with water after the reversed-phase chromatography allows on-line concentration of the labeled analyte onto a guard column prior to the microbore HPLC. A loop guard column device provides a simple way to inject up to 1.0 ml of sample solution onto a microbore column without significantly reducing the column efficiency. A 325-nm He-Cd laser is used to excite the labeled drug, and fluorescence emission is monitored at 450 nm. Using this system, we are able to derivatize, detect, and quantify 5 pg of the prostaglandin analogue in 1.0 ml of plasma.

Principles behind practice. 4. Natural history

The busy clinician is confronted daily with a wide range of decisions about patient diagnosis and management. The sharpness and scepticism to constantly ask fundamental questions about the natural history of a patient's disease is a talent that a few lucky individuals have. For the rest of us, it is an acquired skill which must be developed and maintained. We suggest the following questions to guide the clinician in taking account of the natural history of disease in everyday clinical practice. How strong is the evidence that the putative consequence of this illness is or is not attributable to some external factor? Can I be sure that this exposure (drug, surgery, social or behavioural therapy, toxic or environmental agent) does not have a long latency and that subsequent development of illness will not ensue? What do I know from long-term prospective studies about the life history of this disease? Does lead time explain the apparent benefit of this diagnostic test or other screening procedure? Does the evidence of the natural history of this disease specifically relate to the characteristics of my patient--age, sex, set of prognostic factors, selected or unselected referral? Is there good evidence from at least one good randomised controlled trial with a "no treatment" control group that this intervention is efficacious (and not hazardous)?

Pulse oximetry in acute asthma

The predictive value of pulse oximetry was evaluated in 100 patients who attended the emergency department with acute asthma. Oximetry after treatment with a cut off point of less than 91% had a sensitivity of 42% and specificity of 78% for unfavourable outcome, and oximetry before treatment had a sensitivity of 36% and a specificity of 57%. Despite its low sensitivity, oximetry after treatment does seem to have a role in minimising diagnostic errors in the emergency department, but only when used in conjunction with clinical assessment.

Prevalence of asthma in Melbourne schoolchildren: changes over 26 years

OBJECTIVES

To determine the prevalence of asthma in the past 12 months in Melbourne schoolchildren aged 7, 12, and 15 years and to compare the prevalence of a history of asthma with that of 26 years ago.

DESIGN

A questionnaire on respiratory symptoms was distributed to children for completion by parents and return to the school. Subjects were selected by a stratified cluster design.

SETTING

Government and non-government schools in the greater Melbourne area, Australia.

SUBJECTS

10,981 children. Parents completed questionnaires for 3324 children aged 7, 2899 aged 12, and 2968 aged 15. The overall response rate was 90%.

MAIN OUTCOME MEASURES

History of wheeze or asthma in the past 12 months and in lifetime.

RESULTS

The prevalences of wheeze in the past 12 months were 23.1%, 21.7%, and 18.6% for 7, 12, and 15 year olds respectively. A history of wheeze was more common in boys than in girls at age 7 (443/1711 v 324/1614) and 12 (418/1767 v 322/1718) but not at age 15. Overall, 78% (1548) of those reporting wheeze also reported a history of asthma and 83% (1611) had used a bronchodilator. The prevalence of a history of asthma among 7 year olds was 46% compared with 19.1% in the 1964 survey, an increase of 141%.

CONCLUSIONS

The current prevalence of asthma in Melbourne schoolchildren is high and has risen substantially over the past 26 years.

Revision, replication and neglect--research on maladjustment in chronic illness

Children with chronic physical disorders have twice the risk of psychosocial maladjustment compared with healthy children. This "second handicap" poses a significant mental health problem. This review examines factors related to the child, family, and clinical condition that affect the risk of maladjustment, as well as the manner in which this knowledge has influenced intervention strategies. Much of the research reviewed represents replication of what is already known and important areas of enquiry have been neglected. Investigators are urged to work towards the further identification of high risk characteristics and to apply these to the development and evaluation of new preventive and therapeutic approaches for these children and their families.

Role of IFN-gamma in lethal and nonlethal malaria in susceptible and resistant murine hosts

IFN-gamma plays an important role in host defense against microbial disease. Here, we studied the role of IFN-gamma in lethal and nonlethal murine malaria. Administration of recombinant murine IFN-gamma resulted in a dose-dependent protection of SW, BALB/cByJ, and CBA/J mice from the lethal variant of Plasmodium yoelii 17x (PyL) but had little effect on the course of the nonlethal variant of this parasite (PyNL). Administration of recombinant IFN-gamma also resulted in the activation of peritoneal macrophages for increased phagocytosis of malaria-infected erythrocytes and release of H2O2, as measured in vitro. The ability of spleen cells from infected mice to produce endogenous IFN-gamma and release H2O2 during the course of malaria was also studied. In BALB/cByJ mice, which are relatively susceptible to PyL and PyNL, there was an initial burst of IFN-gamma only in response to PyNL whereas in CBA/J mice, which are relatively resistant to these parasites, there was an initial burst of IFN-gamma in response to both PyL and PyNL. The kinetics of H2O2 release corresponded to that of IFN-gamma. In all infections, levels of IFN-gamma declined as parasitemia increased; however, nonlethal infections were characterized by a recovery of both IFN-gamma activity and H2O2 release as parasitemia declined. These data suggest that IFN-gamma may play an important role in modulating the course of malaria infections by activating macrophages for both intracellular and extracellular parasite destruction.

Role of IFN-gamma in lethal and nonlethal malaria in susceptible and resistant murine hosts

IFN-gamma plays an important role in host defense against microbial disease. Here, we studied the role of IFN-gamma in lethal and nonlethal murine malaria. Administration of recombinant murine IFN-gamma resulted in a dose-dependent protection of SW, BALB/cByJ, and CBA/J mice from the lethal variant of Plasmodium yoelii 17x (PyL) but had little effect on the course of the nonlethal variant of this parasite (PyNL). Administration of recombinant IFN-gamma also resulted in the activation of peritoneal macrophages for increased phagocytosis of malaria-infected erythrocytes and release of H2O2, as measured in vitro. The ability of spleen cells from infected mice to produce endogenous IFN-gamma and release H2O2 during the course of malaria was also studied. In BALB/cByJ mice, which are relatively susceptible to PyL and PyNL, there was an initial burst of IFN-gamma only in response to PyNL whereas in CBA/J mice, which are relatively resistant to these parasites, there was an initial burst of IFN-gamma in response to both PyL and PyNL. The kinetics of H2O2 release corresponded to that of IFN-gamma. In all infections, levels of IFN-gamma declined as parasitemia increased; however, nonlethal infections were characterized by a recovery of both IFN-gamma activity and H2O2 release as parasitemia declined. These data suggest that IFN-gamma may play an important role in modulating the course of malaria infections by activating macrophages for both intracellular and extracellular parasite destruction.

Evaluation of a children's hospital medical peer review programme

The records of medical peer review meetings at the Royal Children's Hospital, Melbourne, were audited for the period 1983-87. This investigation focused on the peer review process, but also evaluated the extent to which recommended changes in medical practice were carried out. The results showed that few recommendations arose from the meetings despite the clear recognition of a number of problem areas. In the instances where firm recommendations were made, few appeared to have been implemented. The main reasons for this failure were: (i) the review was not an integrated part of the medical management structure of the hospital; (ii) recommendations were frequently not made despite clear expressions of the need for action; (iii) the absence of a designated individual to ensure that recommended actions were implemented, together with the lack of a feedback or internal review process to monitor effectiveness; and (iv) a relatively low profile of the peer review. Despite these shortcomings, the peer review is widely perceived to be a valuable exercise, especially as a general educational tool. However, its potential is far greater, and a model is proposed for a more effective medical peer review programme.

Single dose trimethoprim for urinary tract infection

A randomised clinical trial of single dose trimethoprim against a seven day course of co-trimoxazole (trimethoprim/sulphamethoxazole) for the treatment of uncomplicated urinary tract infection was carried out in 106 children aged between 2 and 16 years. Of the 50 children with confirmed urinary tract infections who were followed up 48 hours after treatment with a single dose of trimethoprim all were free of infection, whereas two of the 56 who received the course of co-trimoxazole (4%) had persisting infections. At follow up after 10 days, however, significantly more of the group treated with trimethoprim had evidence of recurrent urinary tract infection compared with those who had received co-trimoxazole (10 of 44, 23%, compared with one of 46, 2%). Of the recurrences in the trimethoprim group, six were asymptomatic. We conclude that single dose trimethoprim is effective in clearing the urine of bacteria, but the risk of asymptomatic bacteriuria soon after treatment is high.

Controlled trial of social work in childhood chronic illness

Children with chronic illnesses have a doubled risk of becoming psychosocially maladjusted, and social-work support and counselling are commonly used to reduce this secondary morbidity. A randomised controlled trial of this type of intervention was conducted in 345 children with chronic physical disorders cared for in eleven specialty clinics at a children's hospital. Four months after a six-month period of social-work services, no significant difference was found between social-work and control groups in overall prevalence of maladjustment. There was no evidence to support a preventive or therapeutic effect of social work on child behaviour disorder or social dysfunction on the principal outcome measure, the Child Behaviour Checklist. Nor was there any detectable effect on child self-esteem, on maternal psychological function, or on the impact of the child's illness on the family. Furthermore, no patient subgroup could be shown to benefit from the intervention, and restriction of the analysis to individuals who received the intervention did not alter the results.

Knowledge of cystic fibrosis in patients and their parents

A standardized questionnaire was used to assess knowledge about cystic fibrosis in 28 patients with cystic fibrosis (aged 10 to 21 years) and in the parents of 25 of these patients. Knowledge of disease pathophysiology and treatment was generally comprehensive and detailed; knowledge of the genetics was fair. However, there were conspicuous deficits in the awareness of reproductive risks and of male sterility. Significant predictors of patient knowledge were patient age, sex, and educational level and parental age. Predictors of parent knowledge were Shwachman score, socioeconomic status, and sex of responding parent. Patients rely heavily on parents for information about cystic fibrosis. More than one third of both patients and parents sought more information about the disease and its implications.

Temperament in infants born prematurely

The temperament of infants born prematurely was studied to examine further the notion that prematurity may be a risk factor for an infant's subsequent social interaction. The Infant Temperament Questionnaire of Carey and McDevitt was revised and revalidated for an Australian population and sent to mothers of infants who had been born prematurely (36 weeks or less) and who were aged 4 to 8 months (corrected for prematurity). Two hundred and twenty-six questionnaires were distributed and 110 (49%) returned. There were no differences between respondents and nonrespondents with respect to gestational age, birth weight, method of delivery, Apgar scores, or perinatal complications. When compared to a control group (N = 240) of infants born at term and who came from families with similar demographic characteristics, infants born prematurely did not differ significantly on any of the nine temperament dimensions. Both groups had similar proportions of "easy," "difficult," and "slow to warm up" infants, and there were no significant differences in maternal global ratings of temperament between the two groups. Comparisons of infants of less than 33 weeks gestation gave results similar to those reported above. These data indicate that infants born prematurely have temperament profiles at 4 to 8 months similar to infants born at term.

Recurrence of a gonadal stromal cell tumor (Sertoli Leydig cell with heterologous elements) in a teenager

An unusual case of a moderately well-differentiated, encapsulated, Sertoli Leydig cell tumor with heterologous elements recurring 3 years after a conservative unilateral oophorectomy in a 15-year-old female is reported. This is the first case report of a metastatic Sertoli Leydig cell tumor with mucinous heterologous elements. A relative lack of uniformly accepted histological criteria of these tumors makes prognosis difficult to access. The optimal therapy for recurrent Sertoli Leydig cell tumor is unknown. Initial plans of management of this rare neoplasm, follow-up, and current concepts of treatment of recurrences will be discussed.