Cannabis use and psychosis: a longitudinal population-based study

Cannabis use may increase the risk of psychotic disorders and result in a poor prognosis for those with an established vulnerability to psychosis. A 3-year follow-up (1997-1999) is reported of a general population of 4,045 psychosis-free persons and of 59 subjects in the Netherlands with a baseline diagnosis of psychotic disorder. Substance use was assessed at baseline, 1-year follow-up, and 3-year follow-up. Baseline cannabis use predicted the presence at follow-up of any level of psychotic symptoms (adjusted odds ratio (OR) = 2.76, 95% confidence interval (CI): 1.18, 6.47), as well as a severe level of psychotic symptoms (OR = 24.17, 95% CI: 5.44, 107.46), and clinician assessment of the need for care for psychotic symptoms (OR = 12.01, 95% CI: 2.24, 64.34). The effect of baseline cannabis use was stronger than the effect at 1-year and 3-year follow-up, and more than 50% of the psychosis diagnoses could be attributed to cannabis use. On the additive scale, the effect of cannabis use was much stronger in those with a baseline diagnosis of psychotic disorder (risk difference, 54.7%) than in those without (risk difference, 2.2%; p for interaction = 0.001). Results confirm previous suggestions that cannabis use increases the risk of both the incidence of psychosis in psychosis-free persons and a poor prognosis for those with an established vulnerability to psychotic disorder.

Care utilization and outcome of DSM-III-R major depression in the general population. Results from the Netherlands Mental Health Survey and Incidence Study (NEMESIS)

OBJECTIVE

To assess care utilization, individual characteristics and clinical and functional outcomes for various modalities of professional care in people with DSM-III-R major depression.

METHOD

Psychiatric diagnoses were determined at baseline and 12-month follow-up in a representative sample (N = 7076) of the Dutch population, using the Composite International Diagnostic Interview (CIDI).

RESULTS

A total of 45.3% of the 223 individuals with major depression received professional care in the 12 months between baseline and follow-up, and 42.6% of these were treated with antidepressant medication. Higher level of care was associated with clinical factors and functional limitations. Clinical outcomes were poorly correlated with functional outcomes. Mild to moderate effects in functional outcome were found for all care modalities.

CONCLUSION

Outcome of antidepressant treatment can be improved and such treatment should focus on the more severe forms of depression. Functional outcome assessment is recommended in addition to clinical assessment.

The structure and stability of common mental disorders: the NEMESIS study

BACKGROUND

We analyzed the underlying latent structure of 12-month DSM-III-R diagnoses of 9 common disorders for the general population in the Netherlands. In addition, we sought to establish (1) the stability of the latent structure underlying mental disorders across a 1-year period (structural stability) and (2) the stability of individual differences in mental disorders at the level of the latent dimensions (differential stability).

METHODS

Data were obtained from the first and second measurement of the Netherlands Mental Health Survey and Incidence Study (NEMESIS) (response rate at baseline: 69.7%, n = 7076; 1 year later, 79.4%, n = 5618). Nine common DSM-III-R diagnoses were assessed twice with the Composite International Diagnostic Interview with a time lapse of 1 year. Using structural equation modeling, the number of latent dimensions underlying these diagnoses was determined, and the structural and differential stability were assessed.

RESULTS

A 3-dimensional model was established as having the best fit: a first dimension underlying substance use disorders (alcohol dependence, drug dependence); a second dimension for mood disorders (major depression, dysthymia), including generalized anxiety disorder; and a third dimension underlying anxiety disorders (simple phobia, social phobia, agoraphobia, and panic disorder). The structural stability of this model during a 1-year period was substantial, and the differential stability of the 3 latent dimensions was considerable.

CONCLUSIONS

Our results confirm the 3-dimensional model for 12-month prevalence of mental disorders. Results underline the argument for focusing on core psychopathological processes rather than on their manifestation as distinguished disorders in future population studies on common mental disorders.

Predictors of incident care service utilisation for mental health problems in the Dutch general population

BACKGROUND

The determinants of first-time ('incident') use of primary care and mental health care services for mental health problems have not been previously investigated. Such information is needed to identify new client groups and to gain a better understanding of causal factors.

METHOD

Data were derived from the Netherlands Mental Health Survey and Incidence Study, NEMESIS, a prospective general population study of adults. Potential predictors of care use (psychiatric disorders, burden of illness, sociodemographic characteristics) were recorded in the first wave of the study, and the utilisation of care services in the second wave. Psychiatric diagnoses were based on the Composite International Diagnostic Interview (CIDI) 1.1.

RESULTS

Six of the ten indicators linked to the frequent utilisation of care were found not to be associated with incident use: higher age, lower income, living alone, paid employment, mood disorders and anxiety disorders. Four other indicators showed associations with both frequent and incident use: female gender, higher numbers of restricted activity days, poorer social functioning and unmet care needs. Two predictors of incident use only were lower educational attainment and being in treatment for a somatic disorder.

CONCLUSION

New clients who come to primary health care or mental health care services with mental health problems are found in all age groups. They are more likely to be women, to have less education, to be in treatment for a somatic disorder and to have functional problems related to their mental health problems.

Determinants of poor 1-year outcome of DSM-III-R major depression in the general population: results of the Netherlands Mental Health Survey and Incidence Study (NEMESIS)

OBJECTIVE

To investigate risk factors of poor 1-year outcome of major depression in the general population and to compare the results with data from clinical populations.

METHOD

Psychiatric diagnoses were determined in a representative sample (N = 7,076) of the Dutch general population, using the Composite International Diagnostic Interview (CIDI) at baseline and 12 months later. A broad range of potential risk factors were evaluated.

RESULTS

Of the depressed people at baseline, 28.3% were depressed 12 months later. Younger age, severity of depression, longer duration of previous episodes, the presence of anhedonia and early awakening, external locus of control and multiple negative life events appear to be risk factors.

CONCLUSION

Poor outcome of major depression is frequent in the general population. Largely the same risk factors are involved as in clinical populations.

Expression of gp100, MART-1, tyrosinase, and S100 in paraffin-embedded primary melanomas and locoregional, lymph node, and visceral metastases: implications for diagnosis and immunotherapy. A study conducted by the EORTC Melanoma Cooperative Group

With the recent availability of novel antibodies against melanoma antigens tyrosinase and MART-1, it is important to validate their usefulness in pathology practice and in screening patients for immunotherapy treatment. In the present study conducted by the Melanoma Cooperative Group of the European Organization for Research and Treatment of Cancer (EORTC-MCG), immunohistochemical staining for gp100 (antibodies NKI-beteb and HMB-45), MART-1 (A103), tyrosinase (T311), and S100 (S100) was compared on formalin-fixed and paraffin-embedded tumour lesions from 80 patients with 130 malignant melanoma lesions, comprising 44 primary tumours, 18 locoregional metastases, 41 lymph node metastases, and 27 visceral metastases from the lung, liver, and brain. A score between 0 and 5 was allocated to each immunohistochemically stained section. These scores were evaluated in a statistical analysis. S100 was by far the most sensitive marker in all four types of lesions tested. Apart from a significantly better performance for T311 in primary melanomas compared with HMB-45, no significant differences were observed between the four remaining antigens tested. Three settings were next investigated to determine whether the expression of melanoma antigens decreases with tumour progression. First, within the primary melanomas, only NKI-beteb and A103 staining showed a nearly significant negative correlation with Clark's level of invasion and a similar tendency was observed for these antibodies with Breslow thickness. Second, when comparing primary melanoma-metastasis pairs from the same patient, lymph node metastases showed less staining with NKI-beteb, HMB-45, A103, and T311, at a level near significance. This difference was not significant when comparing the primary tumour with visceral metastases, probably due to the lower numbers of pairs. Third, regarding tumour progression from primary melanoma to locoregional, to lymph node, to visceral metastasis, a significant decrease with progression was found only for T311. The apparently stable expression of most of the melanoma antigens, and the small contribution of decreased expression in melanoma tumour progression, supports the rationale for immunotherapy based on the melanoma immunogens gp100, MART-1, and tyrosinase.

Same-sex sexual behavior and psychiatric disorders: findings from the Netherlands Mental Health Survey and Incidence Study (NEMESIS)

BACKGROUND

It has been suggested that homosexuality is associated with psychiatric morbidity. This study examined differences between heterosexually and homosexually active subjects in 12-month and lifetime prevalence of DSM-III-R mood, anxiety, and substance use disorders in a representative sample of the Dutch population (N = 7076; aged 18-64 years).

METHODS

Data were collected in face-to-face interviews, using the Composite International Diagnostic Interview. Classification as heterosexual or homosexual was based on reported sexual behavior in the preceding year. Five thousand nine hundred ninety-eight (84.8%) of the total sample could be classified: 2.8% of 2878 men and 1.4% of 3120 women had had same-sex partners. Differences in prevalence rates were tested by logistic regression analyses, controlling for demographics.

RESULTS

Psychiatric disorders were more prevalent among homosexually active people compared with heterosexually active people. Homosexual men had a higher 12-month prevalence of mood disorders (odds ratio [OR] = 2.93; 95% confidence interval [CI] = 1.54-5.57) and anxiety disorders (OR = 2.61; 95% CI = 1.44-4.74) than heterosexual men. Homosexual women had a higher 12-month prevalence of substance use disorders (OR = 4.05; 95% CI = 1.56-10.47) than heterosexual women. Lifetime prevalence rates reflect identical differences, except for mood disorders, which were more frequently observed in homosexual than in heterosexual women (OR = 2.41; 95% CI = 1.26-4.63). The proportion of persons with 1 or more diagnoses differed only between homosexual and heterosexual women (lifetime OR = 2.61; 95% CI = 1. 31-5.19). More homosexual than heterosexual persons had 2 or more disorders during their lifetimes (homosexual men: OR = 2.70; 95% CI = 1.66-4.41; homosexual women: OR = 2.09; 95% CI = 1.07-4.09).

CONCLUSION

The findings support the assumption that people with same-sex sexual behavior are at greater risk for psychiatric disorders.

Psychiatric and sociodemographic predictors of attrition in a longitudinal study: The Netherlands Mental Health Survey and Incidence Study (NEMESIS)

This article discusses the effects of sociodemographics and the presence of psychiatric disorders diagnosed in the 12 months before the first interview by using the Diagnostic and Statistical Manual of Mental Disorders: DSM-III-R, third edition, revised, on three types of attrition (failure to locate, refusal to participate, morbidity/mortality) in the second wave (1997-1998) of the Netherlands Mental Health Survey and Incidence Study, a longitudinal, general population survey of psychopathology among 7,076 subjects aged 18-64 years. Compared with those reinterviewed successfully, persons not located at the 1-year follow-up (n = 219) were more often younger, poorly educated, urban, not cohabiting with a steady partner, and born outside the Netherlands. Refusers (n = 923) had a lower educational level. Morbidity/mortality (n = 72) was associated with higher age, lower educational level, not being employed, and somatic disorders. After adjustment for sociodemographics, none of the disorders was positively associated with refusal. Failure to locate was linked to agoraphobia, alcohol abuse, and the categories of mood, substance use, and eating disorders. Morbidity/mortality was linked to dysthymia, agoraphobia, simple phobia, obsessive-compulsive disorder, and the category of anxiety disorders. Overall attrition was only slightly higher among respondents with one or more disorders (odds ratio = 1.20, 95% confidence interval: 1.04, 1.38). Thus, psychopathology has only weak-to-moderate effects on attrition and is mainly related to failure to locate and morbidity/mortality but not to refusal.

Radiological and clinical results of longterm treatment of rheumatoid arthritis with methotrexate and azathioprine

OBJECTIVE

To study whether the reported superior effect of methotrexate (MTX) compared to azathioprine (AZA) in retarding radiologic progression after one year in rheumatoid arthritis was sustained at 2 and 4 years.

METHODS

All 64 patients enrolled in the original randomized double blind study were invited for an open extension of followup to 4 years including 4-monthly clinical and laboratory assessments and radiographs of hands, wrists, and feet at 2 and 4 years.

RESULTS

After 4 years, 18 patients (58%) from the MTX group and 7 patients (21%) from the AZA group continued the initial study drug. During followup more patients (n = 21) switched from AZA to MTX than vice versa (n = 5). In an intention-to-treat analysis improvement of clinical and laboratory variables at 4 years was more pronounced in the MTX group. Mean radiologic scores increased in both treatment groups during followup. According to an intention-to-treat analysis increase in erosion score at one and 2 years in the MTX group was significantly lower than in the AZA group: after one year MTX group 1.8 versus AZA group 5.3 (p = 0.002); after 2 years MTX 3.5 versus AZA 6.5 (p = 0.05). After 4 years there was a trend toward less progression in the MTX group: MTX 6.8 versus AZA 10.8 (p = 0.09). For the total score, progression in the MTX group was less after one and 2 years. After 4 years marked radiologic progression was observed more often in the AZA group.

CONCLUSION

Drug continuation after 4 years of followup was better for MTX than for AZA. In an intention-to-treat analysis the beneficial effect of MTX on radiologic progression compared with AZA was sustained after 2 years of followup. Thereafter differences between treatment groups leveled off, probably mainly due to the greater number of switches from AZA to MTX than vice versa.

Functional properties of the saphenous vein harvested by minimally invasive techniques

BACKGROUND

Since surgical techniques affect the functional properties of the vessel wall, the present study investigated the influence of minimally invasive harvesting techniques on the vascular reactivity of the saphenous vein.

METHODS

Saphenous vein remnants were obtained after aortocoronary bypass operation from patients subjected to conventional (n = 6), mediastinoscope-assisted (n = 4), or endoscope-assisted venectomy (n = 5). After preservation in University of Wisconsin solution (UW), ring preparations were mounted in a standard organ bath setup and concentration-response curves were constructed for phenylephrine, sodium nitroprusside, and acetylcholine.

RESULTS

Saphenous vein reactivity was not altered after preservation in UW. For the vein preparations harvested by means of the three venectomy methods, no differences were demonstrated for responses to KCl, phenylephrine, or sodium nitroprusside. The maximal endothelium-dependent acetylcholine-induced dilation of precontracted vein rings varied between 5% and 12%, independent of the surgical technique applied.

CONCLUSIONS

It was demonstrated that minimally invasive surgical techniques for harvesting the saphenous vein, which are developed to reduce postoperative complications at the site of explantation, did not affect the vascular reactivity in a different manner than the conventional method.

Broader vaccination of expatriates against HBV infection: do we reach those at highest risk?

BACKGROUND

The effects of the implementation of a new Dutch hepatitis B virus (HBV) vaccination strategy (1991) for expatriates on HBV vaccination status and HBV infection prevalence were evaluated in a group of 864 expatriates returning from HBV-endemic areas.

METHODS

During a routine medical examination at the participating medical centres Dutch expatriates were asked to complete a questionnaire and to donate a serum sample for HBV testing. Blood was tested for antibodies against the hepatitis B core (anti-HBc) and surface antigens (anti-HBs). The serological data were related to information gathered on aspects of residence, sexual risk behaviour and occupational risks.

RESULTS

A significantly higher percentage of expatriates (37%) were vaccinated compared to a previous study in 1987-1989 (14%). However, the percentage of expatriates with HBV infection markers (5%) had not decreased significantly. Moreover, the risk for HBV infection, as determined with a questionnaire, was still affected by well-known risk factors such as homosexual contacts (odds ratio [OR] = 6.6, 95% CI: 1.7-26), more than five casual local partners (OR = 3.6, 95% CI: 1.2-11) and more than five occupational accidents in the last 3 years (OR = 20, 95% CI: 2-187). Detailed analysis of the vaccination status indicated that especially young female expatriates with low risk behaviour (65%) were protected, while older male expatriates with high risk behaviour were less protected (20%).

CONCLUSION

We conclude that the new vaccination strategy has resulted in a higher percentage of expatriates protected. However, only a small proportion was reached of those at highest risk for HBV infection.

Underlying reasons for sexual conduct and condom use among expatriates posted in AIDS endemic areas

Among people who work abroad, sexual activity and therefore the risk of HIV infection appear to be relatively high. Little is known about the factors that influence sexual conduct when staying abroad, separated from their usual social environment. This is why 55 expatriates who had been sexually active in AIDS endemic areas were selected for an in-depth interview from the original sample of 864 Dutch expatriates participating in a study on sexual behaviour and HIV infection. The social and cultural context in which the sexual contacts took place was addressed in these interviews. Qualitative analysis of the data led to the identification of four styles with regard to the meaning of and motivations for having sex abroad: 'the unprepared', 'the fanatical', 'the unaffected' and 'the slightly accessible'. These styles are described separately and attention is paid to the association of these styles with protection behavior.

[Prevalence and relevant background characteristics of deafness and severe hearing loss in the Netherlands]

OBJECTIVE

To determine the prevalence of deafness and severe hardness of hearing among the Dutch population and of some relevant background characteristics.

DESIGN

Study of documents.

SETTING

Dutch schools for deaf and hard-of-hearing children.

METHOD

The number of deaf and severely hard-of-hearing children of 6-12 years who received education or ambulatory supervision at schools for deaf and hard-of-hearing children was counted in the period November 1996-April 1997, and a number of relevant background characteristics were collected. By means of consultation with experts, this number was corrected for children who could not be retrieved by means of the inventory at these schools. To estimate the total number of deaf and severely hard-of-hearing people in the Dutch population, this adjusted number was extrapolated to older and younger year cohorts.

RESULTS

The number of deaf and hard-of-hearing children of 6-12 years, after correction for missing groups, was 0.74 (95% confidence interval (95% CI): 0.69-0.78) per 1000 persons. In 9% the age of onset of the handicap was postlingual; they more often received ambulatory supervision and more often received education at a school for hard-of-hearing children than those with a prelingual auditive handicap. Of the children 29% had a non-Western origin; they less often received ambulatory supervision, and more often received education from a school for deaf children than indigenous pupils. Among the total Dutch population, the number of deaf and hard-of-hearing persons in 1996 was estimated to be 11,400 persons (95% CI: 10,690-12,110).

CONCLUSION

The prevalence of deafness and severe hardness of hearing in the Netherlands (15,490,000 inhabitants in 1996) was 11,400 persons (95% CI: 10,690-12,110).

Occupational risk of HIV infection among western health care professionals posted in AIDS endemic areas

In this study on occupational risks of HIV infection among 99 Dutch medics working in AIDS endemic areas, 61% reported percutaneous exposures during an average stay of 21 months. The mean number of injuries was lower among physicians (2.0 versus 3.9 per year) and higher among nurses (1.9 versus 1.2) than in previous research conducted in 1987-1990 among Dutch medics returning from Africa. But the reduction of exposures among physicians might be explained by the fact that the number of procedures they carried out was less in the later study. Also among nurses a shift of tasks was seen. On the basis of an estimated HIV prevalence in the patient population of 19%, a chance of transmission per accident of 0.3%, and 1.9 percutaneous exposures per year, the mean occupational risk of HIV infection per year can be estimated at 0.11% per person. Besides length of stay and number of activities, characteristics of the work setting were associated with the frequency of different kinds of injuries. From the analysis of 109 extensive descriptions of recent accidents, it appeared that the majority of the injuries occurred during routine activities and were self-inflicted. Injuries with hollow needles usually occurred after the actual medical act (e.g. during recapping). Carelessness (e.g. due to fatigue) or being in a hurry (e.g. because of an emergency) were also often the cause of percutaneous injuries, as were the poor quality of the equipment, lack of professional skills, or a combination of these factors. Prevention activities are still important to reduce the frequency of occupational exposures. But they will not eliminate them totally; from the descriptions of recent exposures it was clear that some of the injuries occurred in spite of precautions.

Neonatal risk factors and risk scores including auditory evoked responses

In a prospective study, 81 preterm infants and 25 healthy term infants were neurologically and neurophysiologically evaluated in the neonatal period. At 5-7 years of age the neurodevelopmental outcome was assessed. The validity and predictive value of the Neonatal Neurological Inventory (NNI) and the Neurobiological Risk Score (NBRS), including an additional gestational age factor (GAF) and an auditory evoked response factor (AERF) were assessed. Three of the 53 surviving preterm infants showed major neurological abnormalities at 5-7 years. Five infants showed neuropsychological abnormalities and 12 infants showed both neurological and neuropsychological abnormalities. An important subgroup of preterm infants could be identified as high-risk using the NNI and NBRS. The low sensitivity and negative predictive value resulted in a number of false-negative results. Logistic regression showed that intraventricular haemorrhage (IVH) and bilirubin levels contributed highly to the prediction of neurological outcome. For neuropsychological outcome these factors were IVH and assisted ventilation. Addition of the GAF and AERF as separate items to the NBRS did not affect the predictive power. Combined addition of the GAF and AERF showed improvement of both validity and predictive value.

CONCLUSION

This study shows that IVH, bilirubin and assisted ventilation contribute most to the validity and predictive value of the NBRS. Furthermore, regarding neurological outcome addition of a GAF in combination with an AERF resulted in a substantial improvement of the validity and predictive value. The shortcomings of the current neonatal risk scores require a careful interpretation of clinical perinatal data regarding the prediction of neurodevelopmental outcome in preterm infants.

Diagnostic and predictive value of auditory evoked responses in preterm infants: II. Auditory evoked responses

In this study, the diagnostic and predictive value of brainstem, middle latency, and cortical auditory evoked responses (BMC-AERs) obtained in the neonatal period in 81 preterm infants was assessed in relation to neurodevelopmental outcome. The preterm infants were neonatally classified according to risk category and gestational age. The BMC-AERs were analyzed with respect to detectability, latencies, and amplitudes as well as derived latency and amplitude measures. At 5 y of age the neurodevelopmental outcome was assessed from neurologic and neuropsychologic evaluations. The results showed that BMC-AER differences mainly correlated with risk category (low risk/high risk) and to some extent with degree of prematurity. In view of these findings the degree of prematurity and the effect of risk category have to be taken into account, when BMC-AERs are applied in the preterm period to predict neurodevelopmental outcome. In this study the BMC-AERs for infants with abnormal neurodevelopmental outcome were scarcely distinguishable from the BMC-AERs for infants with normal neurodevelopmental outcome. Thus far, this and previous reports have indicated that BMC-AERs in preterm infants are useful in maturational studies and with infants showing symptoms related to lesions or dysfunction of the peripheral and/or central auditory system. For predicting neurodevelopmental outcome in preterm infants, BMC-AERs are of limited clinical value.

Diagnostic and predictive value of auditory evoked responses in preterm infants: I. Patient characteristics and long-term neurodevelopmental outcome

The diagnostic and predictive value of brainstem, middle latency, and cortical auditory evoked responses, obtained in the neonatal period, in 81 preterm infants was assessed in relation to neurodevelopmental outcome. Eighteen healthy term infants served as a control group. In this report the patient characteristics and neurodevelopmental outcome are presented. The preterm infants were neonatally classified according to risk category and gestational age. At 5 y of age the neurodevelopmental outcome was assessed based on neurologic and neuropsychologic evaluations. The neuropsychologic test results showed the highest IQ scores in term infants, intermediate IQ scores in low risk preterm infants, and lowest IQ scores in high risk preterm infants. The intermediate IQ scores in the low risk preterm group were due to significantly lower test scores in a small subgroup of low risk preterm infants. In a post hoc analysis 12 low risk preterm infants with an unfavorable outcome could be identified. The neuropsychologic test results of the remaining low risk infants showed no clear differences compared with the term infants. The results suggest that the unfavorable outcome of the low risk preterm group as a whole is due to moderate to severe impairment of the few, rather than slight impairment of the majority.

Condom use by Dutch men with commercial heterosexual contacts: determinants and considerations

We report responses from 559 clients of female prostitutes, with a view to determining to what extent previously identified factors play a part in condom use. To increase the response rate to advertisements in daily and weekly newspapers, interviews were held by phone. This procedure had the advantage of ensuring the anonymity many clients demanded. Of those clients having vaginal or anal contact (91%), 14% had not always used condoms in the previous year. Compared with consistent condom users, these men were less highly educated, had twice as many commercial contacts, and had more contacts with "steady" prostitutes. They were either more emotionally motivated to visit prostitutes than were consistent condom users or exhibited a stronger need for sexual variation. They showed a more compulsive attitude toward visiting prostitutes, had a more negative attitude toward prostitution in general, evaluated condoms more negatively, had a higher personal efficacy to achieve unsafe contacts, and had a higher general risk assessment, commensurate with their behavior. Men with only safe contacts had either an intrinsic or an extrinsic motivation for condom use. Among extrinsically motivated men, their behavior change was more recent and had not yet taken root: They still envisioned unsafe commercial sex to be possible in the future. Education aimed at the small group of men practicing unsafe contacts will not easily and directly lead to behavior change. But these educational activities may support prostitutes to persist in (consistent) condom use, regardless of clients' pressure to do otherwise.

Sexual risk of HIV infection among expatriates posted in AIDS endemic areas

OBJECTIVE

To assess the prevalence of HIV infection and related risk factors among Dutch expatriates returning from assignment in sub-Saharan Africa, Latin America, and South and South-east Asia.

METHODS

From July 1994 to January 1996, a questionnaire on the risks of sexual exposure was completed by 864 respondents, and blood samples were taken.

RESULTS

Of the 634 men, 41% reported having sex with casual or steady local partners and 11% with casual or steady expatriate partners, during an average stay of 26 months in the previous 3 years. Of the 230 women, these figures were 31 and 24%, respectively. Of the men with local casual partners (29%), 59% paid for sex at least once. For men as well as women, having sexual contacts abroad was associated with younger age, positive intention prior to departure to have sex abroad, being single at departure, and, only for the men, working for a commercial organization, and feelings of loneliness and boredom. Among men, consistent condom use with casual local partners was 69%, and with casual expatriate partners 63%. Among women, these figures were 64 and 48%, respectively. Consistent condom use with steady local or expatriate partners was much lower. Among men, non-consistent condom use with casual partners was more prevalent if they had been abroad for a longer time, condoms were not taken along from The Netherlands, the country where they were posted was Asian, and the estimated HIV prevalence among the local population was lower. Among the women, non-consistent condom use was more prevalent if condoms were not taken along, and if they did not have the intention before departure to have sex abroad. Of the persons from whom blood could be obtained, one man was HIV-positive. Another man who refused to participate in the study indicated that he was HIV-positive.

CONCLUSIONS

Although 23% of the expatriates had unprotected sex with partners from endemic areas, very few HIV infections were found. In comparison with a previous study among this population carried out in 1987-1989, which found five out of 1968 expatriates to be HIV-infected, consistent condom use with casual local partners did increase considerably (from 21 to 67%). However, health education is needed to reduce the risk of HIV infection, which should emphasize the sociocultural differences in sexual practices.

Clinical implications of the rise and fall of prostate specific antigen after laser prostatectomy

OBJECTIVE

To characterize the serum kinetics of prostate specific antigen (PSA) after visual laser ablation of the prostate (VLAP).

PATIENTS AND METHODS

The PSA values of 45 patients were measured at 24 h and at 1, 4, 12, 26 and 52 weeks after VLAP and the changes assessed in relation to symptom scores, urinary flow rates and prostate size.

RESULTS

After an initial rise immediately after VLAP, the serum PSA level declined. At 24 h, the PSA value reached a mean level 23 times higher than the PSA level before VLAP and then took a mean of 78 days to reach a new baseline. The mean decrease of the subsequent baseline value relative to that before treatment was 1.7 ng/mL. The prostatic size and energy applied correlated positively with the rise in PSA 24 h after VLAP. The rise in maximal urinary flow after VLAP, the decrease in the symptom score and residual urine volume did not correlate with the rise in PSA level 24 h after VLAP or with the time to reach a value halfway between the level at 24 h and the new baseline value.

CONCLUSIONS

The pattern of the increase in serum PSA level and decline after VLAP was not predictive of the clinical outcome of therapy.

Purine enzyme activities in recent onset rheumatoid arthritis: are there differences between patients and healthy controls?

OBJECTIVE

Purine enzyme activities may predict the effectiveness of azathioprine treatment and be associated with increased deaths from infectious diseases. In rheumatoid arthritis, patients show variable responses to azathioprine and a higher percentage of death is caused by infections. The aim of the study was to investigate possible rheumatoid arthritis associated abnormalities of purine enzyme activities by measuring several of these enzymes in patients with recent onset rheumatoid arthritis before treatment with disease modifying antirheumatic drugs or prednisone.

METHODS

23 patients with recent onset rheumatoid arthritis and 28 healthy controls were studied. Activities of the enzymes 5'-nucleotidase, purine nucleoside phosphorylase (PNP), hypoxanthine guanine phosphoribosyltransferase (HGPRT), and thiopurine methyltransferase (TPMT) were measured. Assessment of disease activity and blood sampling for routine measurements and HLA typing were done simultaneously.

RESULTS

Purine enzyme activities did not differ between patients and healthy controls. Enzyme activities had no significant relations with indices of disease activity or rheumatoid factor titre or with the rheumatoid arthritis associated HLA types. Activity of 5'nucleotidase decreased with age (P < or = 0.05) and was lower by about 27% (P = 0.007) in males than in females.

CONCLUSIONS

In rheumatoid arthritis patients, neither the variability in azathioprine effectiveness nor the increased death rate from infections can be explained by pre-existing abnormalities in the activities of the purine enzymes 5'-nucleotidase, PNP, HGPRT, or TPMT at an early stage of the disease, before disease modifying antirheumatic drugs or prednisone treatment. Besides adjustment for age, results of studies involving purine 5' nucleotidase activity should also be adjusted for sex.

Segmentation of heterosexual prostitution into various forms: a barrier to the potential transmission of HIV

The results of an earlier Dutch study on prostitutes' clients, interviewed face-to-face, were cross-validated by means of telephone interviews, which both guaranteed anonymity and produced a larger sample of respondents (n = 559). Depending on their preference and financial resources, they had visited different types of prostitution; but about half of them had restricted themselves to one type. Inconsistent use of condoms was reported by 14% of the clients who had had vaginal or anal intercourse. Condoms were most frequently used in clubs, brothels and window prostitution, and least often in street, home and escort prostitution; in the last two sorts especially not with regular prostitutes. Whether or not prostitutes came from non-Western countries had no influence on protective behaviour of these clients. The formation of networks between different sorts of prostitution, through unsafe sexual contacts in two or more sorts, involved only 3% of respondents. Thus, prostitution in The Netherlands should be seen as a number of sparsely-connected networks rather than as a single network. The formation of networks between prostitution and the population at large is made possible by the 10% of the respondents who had had unsafe contacts with both commercial and private partners.

The effects of early and late preterm birth on brainstem and middle-latency auditory evoked responses in children with normal neurodevelopment

In preterm and term infants, brainstem and middle latency auditory evoked responses (ABR and MLR) were obtained at 40 and 52 weeks conceptional age (CA) and at 5 years of age. A neurological and neuropsychological evaluation was performed at 5 years of age. To study the effect of preterm birth on the maturation of the ABR and MLR, the preterm infants were divided into early and late preterm groups. Only children with a normal neurodevelopmental outcome at 5 years of age were entered into the study. For ABR, the late preterm group showed significantly longer mean latencies IIc, III, V, and Vc when compared with the term group at 52 weeks CA. There was a trend to longer ABR latencies I in the early preterm group compared with the term group. At 52 weeks CA, the late preterm group showed longer mean interpeak latencies III-I and V-I when compared with the term as well as the early preterm group. At 5 years, the late preterm group showed significantly longer mean ABR latencies IIc and III when compared to the early preterm group. For MLR, the early preterm group showed significantly longer mean latencies of MLR component PO when compared with the term group at 40 weeks CA. At 52 weeks, the late preterm group also had longer mean MLR latencies P0 than the term group. At 5 years of age, the term group showed higher mean peak-to-peak amplitudes Na-P0 than the early as well as the late preterm group. To a large extent, the ABR results support the hypothesis that middle ear effusions in combination with retarded myelination of the central auditory pathway are responsible for the ABR differences found between term and preterm infants with a normal neurodevelopmental outcome at 5 years of age. The longer latencies and interpeak latencies found in late preterm infants when compared with early preterm infants might be explained by an augmented vulnerability of the auditory pathway between 30 and 34 weeks CA. The MLR differences found between term and preterm infants might be explained by a difference in the maturation of primary and nonprimary MLR components.

Professional HIV risk taking, levels of victimization, and well-being in female prostitutes in The Netherlands

Professional HIV risk taking (nonconsistent condom use with clients) of female prostitutes in The Netherlands is addressed within the context of (early) experiences with abuse, well-being, coping behavior, job satisfaction, and financial need. Data were gathered from 127 female prostitutes on condom use, financial need, and professional attitude, and on experiences with violence and abuse, physical complaints, psychosocial problems, and coping responses. Violent traumatic experiences were found to relate to more severe complaints and problems, and a higher frequency of emotion-focused coping strategies. A risk-taking protection style (as opposed to consistent condom use and selective risk taking) appeared to be associated with more severe experiences with violence, both in childhood and in adult life, with more frequent dissociation as a coping behavior, and with more psychosomatic complaints. Of all the relationships found, more severe experiences with violence on the job were most strongly related to a higher professional HIV risk.

Purine enzyme activities in peripheral blood mononuclear cells: comparison of a new non-radiochemical high-performance liquid chromatography procedure and a radiochemical thin-layer chromatography procedure

Purine enzyme activities are usually assayed by radiochemical procedures and often TLC is part of the separation method. In screening patients with rheumatic diseases, these procedures have shown disadvantages like a relatively large coefficient of variation (C.V.) and time-instability. We describe a non-radiochemical reversed-phase HPLC micro-method with UV detection for measurement of activities of purine 5'-nucleotidase (5'NT; EC 3.1.3.5), purine nucleoside phosphorylase (PNP; EC 2.4.2.1) and hypoxanthine guanine phosphoribosyltransferase (HGPRT; EC 2.4.2.8) in human peripheral blood mononuclear cells (PBMC). The HPLC procedure is compared with the radiochemical TLC procedure by testing both with a 5'NT and a PNP assay. Reproducibility is tested with 14 healthy controls in each procedure. Short-term and long-term time-stability is tested by comparing enzyme activities measured immediately after preparation of the PBMC (week 0) with those found after freezing and storage at -20 degrees C for a maximum of 10 weeks. The HPLC procedure is preferable to the radiochemical TLC procedure because it shows significantly better reproducibility and better time-stability and in addition is non-radiochemical and less time-consuming.

Alcohol and drug use in heterosexual and homosexual prostitution, and its relation to protection behaviour

To assess the prevalence and effects of alcohol and drug use in heterosexual and homosexual commercial contacts, and the relationship between their use and unsafe sexual behaviour, 127 female prostitutes, 27 male prostitutes, 91 clients of female prostitutes and 24 clients of male prostitutes were interviewed face-to-face with the help of a semi-structured questionnaire. The respondents were living or working in different parts of The Netherlands. Alcohol and drug use was found to be relatively common among prostitutes. This was also so for the use of alcohol by clients, though to a lesser extent. Prostitutes' consumption varied widely according to the type of prostitution they were employed in. Those meeting their clients in clubs or bars reported the highest consumption of alcohol; hard drugs were used predominantly by street prostitutes. It appears that the main effects of alcohol and drug use are on how the individual experiences working as, or calling on, a prostitute, the social interaction between the two parties, and the sexual contact itself. The common assumption that drinking alcohol has negative effects on condom use was not borne out; though female prostitutes working under the influence of drugs were significantly more likely to report unsafe sex. The degree to which commercial partners were judged to be under the influence of alcohol or drugs was not found to bear upon the frequency of respondents' condom use. For those prostitutes who use hard drugs, this use plays an important role in their engaging in unsafe sexual activities. Prevention activities should focus especially on this group, and should take into account the role of such drug use.

Contextual and interactional factors influencing condom use in heterosexual prostitution contacts

The protection behavior of prostitutes and prostitutes' clients has been studied from a contextual and an interactional point of view. Different protection styles (subject's cognitive and behavioral position regarding condom use) have been identified in both prostitutes (N = 119) and clients (N = 91). Risk-taking prostitutes were found to have the least favorable working conditions, to have the highest financial need, to have the lowest levels of well-being and job satisfaction and to have been victimized more often than consistent condom users and selective risk-taking prostitutes. Consistent condom users among the clients were found to be better educated, to have a less strong external Health Locus of Control, to evaluate condoms and visiting prostitutes more positively, and prostitutes less negatively, and to have more fear of AIDS than non-consistent condom using clients. Various protection styles were found to be thoroughly intertwined with different interaction scenarios. Four different interaction scenarios (a standard, a romantic, a friendship and a fighting scenario) with a different chance of condom use are set forth. It is shown that the scenario approach gives good insight into the process by which unsafe sex in commercial contacts comes about. For both actors, the context and the meaning of prostitution influence the way they play the game. The interaction and its outcome in their turn reinforce their attitudes towards prostitution. Implications for AIDS prevention are discussed.

Purine enzymes in rheumatoid arthritis: possible association with response to azathioprine. A pilot study

OBJECTIVE

To study the possible association of purine enzyme activities with response to azathioprine (AZA) treatment in rheumatoid arthritis (RA) and their correlation with parameters of disease activity.

PATIENTS AND METHODS

Lymphocyte activities of hypoxanthine-guanine phosphoribosyl-transferase (HGPRT), adenine phosphoribosyltransferase (APRT), purine nucleoside phosphorylase (PNP) and 5'-nucleotidase (5NT), and erythrocyte activities of thiopurine methyltransferase (TPMT) were measured in 14 healthy controls and 36 patients with RA. Eight patients had not previously been treated with AZA. Response to AZA therapy in 28 patients, determined in a prospective trial, was considered good in nine (group 1), insufficient in seven (group 2). In 12 patients AZA was withdrawn because of adverse reactions (group 3). Disease activity parameters were obtained simultaneously with purine enzyme measurements. Purine enzyme levels in the different groups were compared.

RESULTS

Levels of 5NT activity were significantly lower in patients with RA than in healthy controls. PNP activity was higher in patients with RA not using prednisone compared with those who did and healthy controls. No clear correlation between purine enzyme levels and disease activity parameters was found. 5NT activities were significantly higher in group one than in group three (p = 0.012; alpha = 0.017), and almost significantly higher than in group two (p = 0.03; alpha = 0.017).

CONCLUSIONS

The results indicate that purine enzyme activities in patients with RA differ from healthy controls, are associated with the outcome of AZA treatment and seem not to be associated with disease activity. Our findings may offer a clue to predict the response to AZA therapy in RA.

Male prostitutes and safe sex: different settings, different risks

Twenty-seven male prostitutes were interviewed extensively about their work and considerations relating to safe sex with clients. Important differences were found between street prostitutes and those working at home. Street-workers were more likely to be using hard drugs, to have a heterosexual preference, to have no other occupation, to have more clients, but less steady ones, and to have a more negative working attitude. Sexual techniques most often practised were manual and oral contact; however, most prostitutes also practised either insertive or receptive anal intercourse. Homosexual male prostitutes reported more receptive anal intercourse than did their heterosexual male colleagues; but no such differences were found in insertive anal intercourse. Prostitutes were most likely to have had anal intercourse with steady clients, with clients whom they trusted regarding condom use, or with clients they felt sexually attracted to; and also when in dire need of drugs. Of those who had practised anal intercourse in the previous year, a minority had not consistently used condoms. The same factors that encourage anal intercourse also appear conducive to unprotected intercourse.

Prognosis of unsuspected but completely resectable N2 non-small cell lung cancer

Of 111 patients with non-small cell lung cancer without clinically evident N2 disease 95 underwent mediastinoscopy between 1975 and 1985. In 63 cases mediastinoscopy was positive and in 32 negative. The patients with a positive mediastinoscopy were considered to have inoperable disease. Their 3- and 5-year survival rates were 5% and 0%, respectively. The patients with a negative mediastinoscopy and 16 patients in whom no mediastinoscopy was performed because of a peripheral tumor underwent operation. They underwent complete tumor resection and mediastinal lymph node dissection. Unsuspected N2 disease was found. Their 3- and 5-year survival rates were 19% and 10%, respectively. The better survival rate in the operated group was statistically significant and mainly due to a better survival of the lobectomy group. Multiple regression analysis showed no favorable prognostic factors in the nonoperated group, but in the operated group lobectomy and central location of the tumor significantly improved the prognosis. We conclude that patients with unsuspected stage IIIa non-small cell lung cancer discovered at thoracotomy benefit from complete tumor resection and mediastinal lymph node dissection, especially if the resection can be confined to lobectomy and if the tumor is located centrally.

Hereditary neuropathy with liability to pressure palsies: a clinical, electroneurophysiological and morphological study

Clinical, electroneurographic and myographic studies were performed on 99 patients of 13 families having hereditary neuropathy with liability to pressure palsies (HNPP) and on 116 relatives. Diagnosis was confirmed in all families by a nerve biopsy of the index case. Large focal myelin thickenings (tomacula) were found in nerve biopsies of affected persons, whether or not pressure palsies had occurred. By using three electroneurographical parameters it was possible to discriminate between asymptomatic patients and unaffected relatives. Complaints sometimes mentioned in literature as being associated with HNPP such as low back pain, brachialgia and short lasting paraesthesia are not related to HNPP. The hereditary transmission is autosomal dominant with total penetration but variable expression.

The effectiveness of condom use in heterosexual prostitution in The Netherlands

OBJECTIVES

To assess the extent to which condoms are used effectively in commercial heterosexual intercourse. Data on the number of condoms that had broken or slipped off, the sexual technique during which this had occurred and the perceived cause of failure were collected. The use of non-water-soluble lubricants and non-fortified condoms during anal intercourse, and the demand for a greater variety of condom sizes were also examined.

SUBJECTS AND METHODS

One hundred and twenty-seven female prostitutes and 91 male clients from different parts of The Netherlands were interviewed face-to-face between July 1990 and March 1991.

RESULTS

Of those who used condoms during vaginal intercourse, 49% of the prostitutes had experienced condom breakage in the previous 6 months, and 16% of the clients in the previous 12 months. The breakage rate was 0.8% for prostitutes and 1.5% for clients. Condom quality was seldom reported as the cause; breakage was generally attributed to human factors, such as rough or prolonged intercourse, incorrect handling of the condom or the use of insufficient lubricant. Prostitutes also identified penis size as a cause. Condoms slipping off before or after ejaculation was reported less frequently than breakage. Thirteen per cent of clients and 36% of prostitutes expressed a need for either smaller or larger condoms. Of the prostitutes, 9% used oil or vaseline as a lubricant.

CONCLUSIONS

In view of the low rate of condom failure in heterosexual prostitution in The Netherlands, the potential spread of HIV by this means is small. The use of a greater variety of condom sizes may further reduce the failure rate. Few prostitutes remain ignorant about the adverse effects of oil-based lubricants on condoms.

The effect of preterm birth on brainstem, middle latency and cortical auditory evoked responses (BMC AERs)

Recent studies on the maturation of auditory brainstem evoked responses (ABRs) present conflicting results, whereas only sparse reports exist with respect to the maturation of middle latency auditory evoked responses (MLRs) and auditory cortical evoked responses (ACRs). The present study reports the effect of preterm birth on the maturation of auditory evoked responses in low risk preterm infants (27-34 weeks conceptional age). The ABRs indicate a consistent trend towards longer latencies for all individual ABR components and towards longer interpeak latencies in preterm infants. The MLR shows longer latencies for early component P0 in preterm infants. The ACRs show a remarkable difference between preterm and term infants. At 40 weeks CA the latencies of ACR components Na and P2 are significantly longer in term infants, whereas at 52 weeks CA the latencies of the same ACR components are shorter in term infants. The results support the hypothesis that retarded myelination of the central auditory pathway is partially responsible for differences found between preterm infants and term infants with respect to late ABR components and early MLR component P0. Furthermore, mild conductive hearing loss in preterm infants may also play its role. A more complex mechanism is implicated to account for the findings noted with respect to MLR component Na and ACR components Na and P2.

Maturation of mitochondrial and other isoenzymes of creatine kinase in skeletal muscle of preterm born infants

We studied pre- and postnatal changes in total creatine kinase (CK) activity, mitochondrial creatine kinase (Mi-CK) activity and immunochemical reactivity with anti-Mi-CK antibodies in skeletal muscle specimens from 12 infants, 10 of them preterm born, after a pregnancy varying between 28 and 40 weeks. Our results demonstrate that Mi-CK is present in fetal human quadriceps muscle and that the specific activity of Mi-CK increases during prenatal development from week 28 to 40 by a factor about two. Generally, adult levels have not been reached at birth, indicating a further postnatal increase of the activity of the enzyme. The Mi-CK protein content also increases during prenatal development. These results suggest that in human skeletal muscle the expression and accumulation of Mi-CK starts at mid-gestation, later than is known to occur for cytosolic CK.

Detectability of auditory evoked response components in preterm infants

In determining the detectability of brainstem, middle latency and cortical auditory evoked responses in preterm newborns, one has to deal with the ongoing maturation of the auditory system. In the preterm period the detectability of evoked responses is closely related to the appearance of the individual evoked response components. The detectability of the individual evoked response components in preterm infants is important, because low detectability rates make the absence of a particular evoked response component irrelevant with respect to the clinical-neurophysiological correlation. In a longitudinal study we determined the detectability and cumulative detectability, i.e. the presence of individual evoked response components in one or more recordings of evoked response components in 37 low risk preterm infants between 30 and 41 weeks conceptional age (CA). On the basis of their detectability it is concluded that evoked response components, determined between 30 and 34 weeks CA, are generally of limited use for clinical application, except for auditory brainstem response (ABR) components I, IIn, V and Vc and middle latency response (MLR) component Na. Our study made clear that improvement can be achieved by performing more than one examination within a period of approximately 4 weeks between the recording sessions. The cumulative detectability rates after two recordings showed improvement for all components involved in this study. The cumulative detectability rates of ABR components I, II, IIN, III, V, IIc, IIINc, Vc, MLR components Na and P0, and auditory cortical response (ACR) components PbP1 and N2p are sufficient to use as measures in the neurophysiological judgement of functional integrity of the central auditory pathway in preterm infants.

Familial selective IgA deficiency with circulating anti-IgA antibodies: a distinct group of patients?

Two families were investigated in which the mothers had selective IgA deficiency and circulating class-specific anti-IgA antibodies. Both gave birth to two children who were found to be IgA deficient. Three of these children developed anti-IgA antibodies before puberty. In vitro immunoglobulin production studies performed in the children of both families revealed an IgA B cell defect combined with IgA-specific excessive T suppressor function in all four. The mechanisms by which transplacental passage of maternal anti-IgA antibodies could have interfered with the developing IgA system in the offspring are discussed.

Ambulatory 24-hour pH-metry in the diagnosis of gastroesophageal reflux disease. Determination of criteria and relation to endoscopy

The results of ambulatory 24-h esophageal pH monitoring in 67 patients with gastroesophageal reflux symptoms (endoscopic esophagitis, n = 44; normal endoscopy, n = 23) were compared with those of 27 normal subjects without reflux symptoms. Patients with reflux symptoms had significantly increased gastroesophageal reflux compared with normal subjects. Acid reflux time was significantly (p less than 0.001) correlated with the severity of endoscopic esophagitis. Linear discriminant analysis was used to differentiate, for each reflux variable, between patients and controls. When the percentage of overall time at pH below 4 was used as a single determinant of gastroesophageal reflux, the sensitivity and specificity were 81% and 85%, respectively, with 4% as upper limit of normal. Pathologic reflux was found in 61% of the patients with negative endoscopy. Long-term ambulatory pH-metry is of clinical value in detecting pathologic reflux in symptomatic patients with negative endoscopy.

Anteroposterior drawer measurements in the knee using an instrumented test device

A newly developed instrumented knee laxity tester was used to measure anteroposterior (AP) drawer parameters (Lachmann test) in populations of normal subjects and patients with anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) insufficiencies. The AP drawer tester features a differential electronic measuring procedure of displacements between patella and tuberosity over a continuous range between 180 and -180 N of AP forces. In the statistical evaluation, shift and compliance (or stiffness) parameters at various forces are considered. In a representative normal population, all relevant parameters were established, thus creating a normal data base for future reference. The average normal AP drawer shift between maximal anterior and posterior forces (180 N) was 6.4 +/- 1.7 mm. Right-left differences and male-female differences were found not to be statistically significant in any of the parameters. The validity of the instrumented drawer tester was confirmed relative to a group of patients with acute documented ligament insufficiencies. Measurements in two groups of patients with chronic postoperative knee instabilities revealed that although the diagnosis of instability could be confirmed, the results could hardly discriminate between ACL and PCL insufficiencies, probably due to unrecognized associated lesions at the time of operation and/or gradual postoperative developments of insufficiencies and deformities. An unexpected finding was that the mean laxities of the uninjured contralateral knees were significantly extended relative to the normal reference group, suggesting that these patients could have been classified as a high-risk group even before the time of injury.

Cortisol and Plasmodium falciparum infection in pregnant women in Kenya

Women living under holoendemic conditions of malaria in Kenya exhibited an increased prevalence of clinical malaria during pregnancy. In addition parasite rate and density were higher in primigravidae compared to multigravidae. Higher serum cortisol concentrations were found in women with patent malaria during pregnancy and the levels were higher before, during and after the malaria episode. A causal relation between serum cortisol levels and suppression of malaria immunity during pregnancy is discussed.

Cortisol and loss of malaria immunity in human pregnancy

The concentration of both total (bound to corticoid-binding-globulin plus free) and free cortisol was determined in sera from two groups of pregnant women in Tanzania. One group consisted of 152 pregnant women (57 nulliparas and 95 multiparas) exhibiting clinical malaria during pregnancy, and the other group comprised 527 pregnant women (105 nulliparas and 422 multiparas), who did not have a record of malaria during pregnancy. The serum concentration of total cortisol was significantly higher in women with clinical malaria than in women without recorded malaria, and this is true for both nulliparae and multiparae. Free cortisol fractions did not differ significantly between these groups. Indications were obtained that higher total cortisol levels cause loss of malaria immunity rather than being concomitant with malaria infection only. The data are compatible with those of a murine malaria model.

Accuracy and reproducibility of instrumented knee-drawer tests

Instrumented devices for knee-drawer tests have become popular in orthopaedics relatively recently. The objective of the present study was to document the effects of several parameters on the accuracy and reproducibility of anterior-posterior (AP) drawer measurements. An instrumented knee-drawer tester for AP laxity evaluations was constructed, based on the differential displacement method, measuring shifts of the tuberosity relative to the patella. The accuracy of the AP-shift was determined with the parallel use of a highly accurate roentgen stereo photogrammetric (RSP) measurement system on two postmortem leg specimens. The effects of relative motion between patella and femur were negligible. In addition to AP shifts, significant knee flexion and tibial rotations occurred, although the foot and the thigh were fixed as well as possible. The differential displacement method was effective in circumventing this problem. The accuracy of the AP shift was greater than 10%. The reproducibility of the AP drawer parameters (shifts and compliances) was determined in normal subjects and patients. Tests were made to evaluate the effects of different observers, time sequences, and different days. In addition, effects of muscle relaxation were studied. Overall, the shift parameters at different forces were found to be reproducible to between 5 and 15%. The slopes (compliances) of the laxity curves, at different forces, were found to be reproducible between 20 and 40%. The reproducibility was principally affected by deviations in the subject positioning procedure.

The maturation of the central auditory conduction in preterm infants until three months post term. V. The auditory cortical response (ACR)

Auditory cortical evoked responses (ACRs) were recorded in 65 preterm infants, at least on 3 occasions in 48 of them. The infants were divided into 5 groups according to their gestational age (GA). The recording sessions were performed at 8 conceptional age (CA) levels, defined as the gestational age added to the chronological age. The last recordings were obtained at 50-52 weeks CA. The ACRs were analyzed for the primary complex containing middle latency components (MLR) and the secondary complex, containing the slow late components. The ACR records first appear at about 25 weeks CA, initiating the premature stage followed by a transitional stage around term date and the gradual development into the mature stage, achieved at 50-52 weeks CA. The detectability rate of the various components generally increased with increasing conceptional age, for some of the components, especially N2p and N2, this rate achieved a value of about 80%. The degree of prematurity did not influence appreciably the development of the ACR. The waveforms, and to a lesser extent the latency and amplitude values, are strongly age dependent. Remarkable topographic differences between the ACR parameter latency and more importantly amplitude values are found between the derivations from the vertex and the central temporal areas, supporting the theory of different generation sites for the ACR components. The premature and mature ACR appeared relatively insensitive to changes in the states of vigilance. The ACR in premature infants are useful in developmental studies with respect to the central audition in premature infants and might contribute in the clinical assessment on the quality of the premature central auditory system.

The maturation of the central auditory conduction in preterm infants until three months post term. II. The auditory brainstem responses (ABRs)

Auditory evoked brainstem responses (ABRs) were recorded in 65 preterm infants (serially in 55 of them), divided into 5 groups, according to their gestational age (GA). The recording sessions were performed at 8 conceptional age levels (CA = GA + chronological age), of which the last two were about 40 and 52 weeks CA. The number of recording sessions varied from one to seven. A full set of ABR latency and amplitude parameters was analyzed including peaks I, II, IIN, III, V and IIc, IIINc and Vc as well as some interpeak latency differences (IPLDs), and the amplitude ratios. The detectability of the different components in the ABR tests at 70 dB reached 80-100% at about 32 weeks CA. The side of stimulation nor the state of vigilance influences the detectability. The degree of prematurity in the 5 GA groups did not influence the development of the parameters. Neither the side of stimulation nor generally the state of vigilance give rise to different parameter values. The thresholds show an age dependent decrease, which is also determined by central maturation. The differential development of the latency decrease of the ABR parameters with increasing conceptional age can be associated with morphological maturational processes and may add weight to the arguments in the delineation of the sources of the ABR. The ipsi- and contralateral central conduction V-II and Vc-IIc do not show latency differences at any CA level. The components IIc and Vc, however, lagged behind in absolute latency compared with II and V. It is concluded that the ABR is a powerful instrument for the study of the maturation of the human auditory pathway in the brainstem. In view of the variability, the detectability and the complex changes within the ABR during the preterm period, its application for clinical purposes during this period has a limited value.

The maturation of the central auditory conduction in preterm infants until three months post term. III. The middle latency auditory evoked response (MLR)

Middle latency auditory evoked responses (MLRs) were recorded in 64 premature infants; serially in 54 of them. The last recording sessions occurred at 50-52 weeks conceptional age (CA), defined as the gestational age (GA) added to the chronological age. The MLRs were analyzed for the components PO, Na and Pa, and the interpeak latency difference (IPLD) Na-PO. The detectability rate of PO and Na reached 80-90% at about 30 weeks CA. Pa reached the highest rate of about 60% at 52 weeks CA. The degree of prematurity did not result in clear differences with respect to the parameter values. Also, the side of stimulation did not influence the MLR parameter values. The latency values of the MLR components are strongly age dependent. Topographic differences were found between the sides ipsi- and contralateral to stimulation. They are, however, different for PO, Na and Pa. The influence of the state of vigilance on the parameter values could generally only be established at CA levels of about 32 and 52 weeks CA. The amplitude values at 52 weeks CA are especially sensitive for sleep or awake state. The particular pattern of age dependency of the different components and their topographic differences are consistent with a differential generation of bilateral nature. The early appearance of the response supports the generation of an early functioning subcortical structure in the auditory pathway.

Cortisol levels in human pregnancy in relation to parity and age

Data are presented of a study on the relationship between cortisol, amenorrhea, parity, and age among pregnant women. Total cortisol concentrations were measured by a radioimmunoassay in healthy pregnant women (n = 527), including 105 nulliparas and 422 multiparas. The serum concentration of total cortisol increased linearly with progression of amenorrhea. Significantly higher cortisol levels were found in nulliparas compared to multiparas and independent of amenorrhea. Since parity and age are strongly correlated, age-dependent changes may contribute to the difference in cortisol level between nulliparas and multiparas. Analysis of the age-dependent changes on this difference in cortisol level showed no significant influence.

Feasibility of a concanavalin A-peroxidase labeling method to detect cancerous and precancerous lesions of the uterine cervix

For the detection of cancerous and precancerous lesions in cervical cytopathology, the feasibility of a concanavalin A-peroxidase labeling procedure was tested and compared with the Papanicolaou method. To this end, the percentage of labeled flattened epithelial cells with a morphologically normal appearance present in cervical cell suspensions was determined. It was found that the mean labeling percentage of the control group was 71% (SD, 11%). The means for mild, moderate, and severe dysplasia groups were, respectively, 54% (SD, 19%), 48% (SD, 13%), and 44% (SD, 16%). The mean for the carcinoma in situ group was 32% (SD,11%), and for the squamous cell carcinoma group 16% (SD, 5%). It appeared that the labeling percentage gradually decreases with increasing atypia of the epithelium as confirmed by histological observation. A complete dissimilarity was found between healthy individuals and cancer patients. In a follow-up study it was found that the mean labeling percentage did not alter in cases of an unchanged stage of disease. A reestablishment of the normal concanavalin A-peroxidase labeling percentage often appeared once the cancerous or precancerous lesion was treated. In conclusion, the concanavalin A-peroxidase labeling method can be considered as a supplementary technique to the Papanicolaou method for the early detection of cervical cancer. It reduces the effect of sampling and screening errors of the Papanicolaou method, and it allows a more objective cytological diagnosis. In addition, it may possess prognostic significance.