Childhood hospitalisation with infection and cardiovascular disease in early-mid adulthood: a longitudinal population-based study

Background

Pathogen-specific and overall infection burden may contribute to atherosclerosis and cardiovascular disease (CVD), but the effect of infection severity and timing is unknown. We investigated whether childhood infection-related hospitalisation (IRH, a marker of severity) was associated with subsequent adult CVD hospitalisation.

Methods

Using longitudinal population-based statutorily-collected administrative health data from Western Australia (1970-2009), we identified adults hospitalised with CVD (ischaemic heart disease, ischaemic stroke, and peripheral vascular disease) and matched them (10:1) to population controls. We used Cox regression to assess relationships between number and type of childhood IRH and adulthood CVD hospitalisation, adjusting for sex, age, Indigenous status, socioeconomic status, and birth weight.

Results

631 subjects with CVD-related hospitalisation in adulthood (≥ 18 years) were matched with 6310 controls. One or more childhood (< 18 years) IRH was predictive of adult CVD-related hospitalisation (adjusted hazard ratio, 1.3; 95% CI 1.1-1.6; P < 0.001). The association showed a dose-response; ≥ 3 childhood IRH was associated with a 2.2 times increased risk of CVD-related hospitalisation in adulthood (adjusted hazard ratio, 2.2; 95% CI 1.7-2.9; P < 0.001). The association was observed across all clinical diagnostic groups of infection (upper respiratory tract infection, lower respiratory tract infection, infectious gastroenteritis, urinary tract infection, skin and soft tissue infection, and other viral infection), and individually with CVD diagnostic categories (ischaemic heart disease, ischaemic stroke and peripheral vascular disease).

Conclusions

Severe childhood infection is associated with CVD hospitalisations in adulthood in a dose-dependent manner, independent of population-level risk factors.

Risk factors and comorbidities for invasive pneumococcal disease in Western Australian Aboriginal and non-Aboriginal people

Australian Aboriginal people have among the highest rates of invasive pneumococcal disease (IPD) worldwide. We investigated clinical diagnosis, risk factors, comorbidities and vaccine coverage in Aboriginal and non-Aboriginal IPD cases. Using enhanced surveillance, we identified IPD cases in Western Australia, Australia, between 1997 and 2007. We calculated the proportion with risk factors and comorbidities in children (<5 years) and adults (=15 years), as well as adults living in metropolitan and non-metropolitan regions. We then calculated the proportion of cases eligible for vaccination who were vaccinated before contracting IPD. Of the 1,792 IPD cases that were reported, 355 (20%) were Aboriginal and 1,155 (65%) were adults. Pneumonia was the most common diagnosis (61% of non-Aboriginal and 49% of Aboriginal adult IPD cases in 2001–2007). Congenital abnormality was the most frequent comorbidity in non-Aboriginal children (11%). In Aboriginal children, preterm delivery was most common (14%). Ninety-one percent of non-Aboriginal and 96% of Aboriginal adults had one or more risk factors or comorbidities. In non-Aboriginal adults, cardiovascular disease (34%) was the predominant comorbidity whilst excessive alcohol use (66%) was the most commonly reported risk factor in Aboriginal adults. In adults, comorbidities were more frequently reported among those in metropolitan regions than those in non-metropolitan regions. Vaccination status was unknown for 637 of 1,082 cases post-July 2001. Forty-one percent of non-Aboriginal and 60% of Aboriginal children were eligible for vaccination but were not vaccinated. Among adults with risk factors who were eligible for vaccination and with known vaccination status, 75% Aboriginal and 94% non-Aboriginal were not vaccinated. An all-of-life immunisation register is needed to evaluate vaccine coverage and effectiveness in preventing IPD in adults.

How Accurate Are International Classification of Diseases-10 Diagnosis Codes in Detecting Influenza and Pertussis Hospitalizations in Children?

Influenza and pertussis are major causes of pediatric morbidity. We measured the accuracy of their International Classification of Diseases (ICD-10-AM) diagnosis codes using linked population-based laboratory and hospital data in 245,249 children. Influenza diagnosis codes had high specificity (98.6%) and modest positive predictive value (PPV; 84.1%) and sensitivity (86.1%, 95% CI: 83.4%-88.6%) for a laboratory-confirmed episode. For pertussis diagnosis codes, PPV (86.8%) and specificity (98.9%) were high, but sensitivity was poor (27.8%, 95% CI: 23.5%-32.4%). Measures varied according to age, remoteness, Aboriginality, severity, and detection method. Both laboratory and hospitalization data are needed to accurately determine the burden of pediatric influenza and pertussis.

Modelling the seasonal epidemics of respiratory syncytial virus in young children

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of paediatric morbidity. Mathematical models can be used to characterise annual RSV seasonal epidemics and are a valuable tool to assess the impact of future vaccines.

OBJECTIVES

Construct a mathematical model of seasonal epidemics of RSV and by fitting to a population-level RSV dataset, obtain a better understanding of RSV transmission dynamics.

METHODS

We obtained an extensive dataset of weekly RSV testing data in children aged less than 2 years, 2000-2005, for a birth cohort of 245,249 children through linkage of laboratory and birth record datasets. We constructed a seasonally forced compartmental age-structured Susceptible-Exposed-Infectious-Recovered-Susceptible (SEIRS) mathematical model to fit to the seasonal curves of positive RSV detections using the Nelder-Mead method.

RESULTS

From 15,830 specimens, 3,394 were positive for RSV. RSV detections exhibited a distinct biennial seasonal pattern with alternating sized peaks in winter months. Our SEIRS model accurately mimicked the observed data with alternating sized peaks using disease parameter values that remained constant across the 6 years of data. Variations in the duration of immunity and recovery periods were explored. The best fit to the data minimising the residual sum of errors was a model using estimates based on previous models in the literature for the infectious period and a slightly lower estimate for the immunity period.

CONCLUSIONS

Our age-structured model based on routinely collected population laboratory data accurately captures the observed seasonal epidemic curves. The compartmental SEIRS model, based on several assumptions, now provides a validated base model. Ranges for the disease parameters in the model that could replicate the patterns in the data were identified. Areas for future model developments include fitting climatic variables to the seasonal parameter, allowing parameters to vary according to age and implementing a newborn vaccination program to predict the effect on RSV incidence.

Morbidity due to acute lower respiratory infection in children with birth defects: a total population-based linked data study

BACKGROUND

Acute lower respiratory infections (ALRIs) are leading causes of hospitalisation in children. Birth defects occur in 5% of live births in Western Australia (WA). The association between birth defects and ALRI hospitalisation is unknown.

METHODS

We conducted a retrospective cohort study of 245,249 singleton births in WA (1996-2005). Population-based hospitalisation data were linked to the WA Register of Developmental Anomalies to investigate ALRI hospitalisations in children with and without birth defects. We used negative binomial regression to estimate associations between birth defects and number of ALRI hospitalisations before age 2 years, adjusting for known risk factors.

RESULTS

Overall, 9% of non-Aboriginal children and 37% of Aboriginal children with birth defects had at least one ALRI admission before age 2 years. Aboriginal children (IRR 2.3, 95% CI: 1.9-2.8) and non-Aboriginal children (IRR 2.0, 95% CI: 1.8-2.2) with birth defects had higher rates of hospitalisation for an ALRI than children with no birth defects. Rates of ALRI hospitalisation varied by type of defect but were increased for all major birth defects categories, the highest rate being for children with Down syndrome (IRR 8.0, 95% CI: 5.6-11.5). The rate of ALRI hospitalisation was 3 times greater in children with multiple birth defects than in those with isolated defects.

CONCLUSIONS

Children with birth defects experience higher rates of hospitalisation for ALRIs before age 2 years than children with no birth defects. Optimal vaccination coverage and immunoprophylaxis for specific categories of birth defects would assist in reducing hospitalisation rates for ALRI.

Can linked emergency department data help assess the out-of-hospital burden of acute lower respiratory infections? A population-based cohort study

Background

There is a lack of data on the out-of-hospital burden of acute lower respiratory infections (ALRI) in developed countries. Administrative datasets from emergency departments (ED) may assist in addressing this.

Methods

We undertook a retrospective population-based study of ED presentations for respiratory-related reasons linked to birth data from 245,249 singleton live births in Western Australia. ED presentation rates <9 years of age were calculated for different diagnoses and predictors of ED presentation <5 years were assessed by multiple logistic regression.

Results

ED data from metropolitan WA, representing 178,810 births were available for analysis. From 35,136 presentations, 18,582 (52.9%) had an International Classification of Diseases (ICD) code for ALRI and 434 had a symptom code directly relating to an ALRI ICD code. A further 9600 presentations had a non-specific diagnosis. From the combined 19,016 ALRI presentations, the highest rates were in non-Aboriginal children aged 6–11 months (81.1/1000 child-years) and Aboriginal children aged 1–5 months (314.8/1000). Croup and bronchiolitis accounted for the majority of ALRI ED presentations. Of Aboriginal births, 14.2% presented at least once to ED before age 5 years compared to 6.5% of non-Aboriginal births. Male sex and maternal age <20 years for Aboriginal children and 20–29 years for non-Aboriginal children were the strongest predictors of presentation to ED with ALRI.

Conclusions

ED data can give an insight into the out-of-hospital burden of ALRI. Presentation rates to ED for ALRI were high, but are minimum estimates due to current limitations of the ED datasets. Recommendations for improvement of these data are provided. Despite these limitations, ALRI, in particular bronchiolitis and croup are important causes of presentation to paediatric EDs.

Use of data linkage to investigate the aetiology of acute lower respiratory infection hospitalisations in children

AIM

To document the aetiology of acute lower respiratory infection (ALRI) hospitalisations in Western Australian children by linking population-based laboratory data with hospital morbidity data.

METHODS

Data from all ALRI hospitalisations and laboratory records related to respiratory pathogens between 2000 and 2005 were extracted and linked through a population-based record linkage system. The proportion of specimens that were positive for each respiratory viral or bacterial pathogen was documented.

RESULTS

Eight thousand nine hundred and eighty (45.2%) ALRI hospitalisations were linked to a laboratory record. Admissions to a private hospital and admissions from non-metropolitan areas were less likely to have a linked laboratory record. In 57.9% of linked hospitalisations, a respiratory virus and/or a bacterial pathogen was identified. Frequently identified viral pathogens included respiratory syncytial virus (RSV; n= 3226; 39.5% of those tested), influenza viruses (n= 664; 8.5%), parainfluenza virus type 3 (n= 348; 4.6%), picornaviruses (n= 292; 22.3%) and adenoviruses (n= 211; 2.7%). RSV was identified in 63.7% of bronchiolitis admissions in those aged under 6 months and 33.1% of pneumonia admissions in those aged under 12 months. Influenza viruses were identified in 81.6% of influenza-coded admissions. When a test was requested, Bordetella pertussis was identified in 21.2% of ALRI hospitalisations (n= 354), including 86.8% of whooping cough-coded admissions.

CONCLUSIONS

This is the first report of population-based data linkage between statewide laboratory data and hospitalisation records and demonstrates proof of principle. RSV continues to be an important pathogen in ALRI. As pathogens were identified across all diagnoses, relying on hospital diagnosis coding alone may not accurately estimate the burden of different categories of ALRI.

Hospitalisation for bronchiolitis in infants is more common after elective caesarean delivery

BACKGROUND

The authors previously reported an increased risk of hospitalisation for acute lower respiratory infection up to age 2 years in children delivered by elective caesarean section. In view of increasing rates of elective caesarean delivery, this association warranted further investigation.

OBJECTIVE

To examine associations between the number of hospital admissions for bronchiolitis and pneumonia and elective caesarean delivery.

DESIGN

Retrospective population-based data linkage cohort study of 212 068 non-Aboriginal singleton births of 37-42 weeks gestation.

METHODS

Negative binomial regression was used to examine associations between mode of delivery and hospitalisations for both bronchiolitis and pneumonia in children aged <12 months and 12-23 months. Models were adjusted for obstetric and known risk factors.

RESULTS

16% of children were delivered by elective caesarean section (n=33 421). In adjusted analysis, compared with spontaneous vaginal delivery, these children had increased risk of admissions for bronchiolitis at age <12 months (incidence rate ratio (IRR) 1.11; 95% CI 1.01 to 1.23) and 12-23 months (IRR 1.20; 95% CI 0.94 to 1.53) independent of other fetal and maternal factors. There was no association between elective caesarean delivery and number of pneumonia admissions aged <12 months (IRR 1.03; 95% CI 0.80 to 1.33) and 12-23 months (IRR 1.09; 95% CI 0.88 to 1.34).

CONCLUSION

Delivery by elective caesarean was independently associated with infant admissions for bronchiolitis but not pneumonia. Elective caesareans or delivery without labour may result in impaired immunity in the newborn leading to increased risk of early viral lower respiratory infections.

Lessons from the first year of the WAIVE study investigating the protective effect of influenza vaccine against laboratory-confirmed influenza in hospitalised children aged 6-59 months

BACKGROUND

Influenza is major cause of paediatric hospitalisation. Influenza vaccine was offered to all children aged 6-59 months resident in Western Australia in 2008, and we wished to evaluate the effectiveness of this immunisation programme.

OBJECTIVES

To assess the practicalities of a nested matched case-control design to estimate the protective effect of inactivated influenza vaccination in hospitalised children aged 6-59 months.

METHODS

Cases were hospitalised children with laboratory-confirmed influenza, while matched controls were recruited from children admitted for an acute non-respiratory illness. We estimated influenza vaccine effectiveness (VE) against influenza as 1--the adjusted odds ratio from multivariate logistic regression.

RESULTS

The 2008 influenza season was characterised by a late peak and a predominance of influenza virus B. We recruited 26 hospitalised patients with laboratory-confirmed influenza and 50 matched controls. The proportion of cases who were fully vaccinated was 7% versus 30% of controls giving an adjusted VE of 83% (95% CI--54 to 98).

CONCLUSIONS

Recruiting sufficient controls was problematic and in the future, we will select controls hospitalised for an influenza-like-illness but influenza negative by laboratory PCR testing. The VE estimate was high but non-significant, reflecting the low number of cases.

A retrospective population-based cohort study identifying target areas for prevention of acute lower respiratory infections in children

Background

Acute lower respiratory infections (ALRI) are a major cause of hospitalisation in young children. Many factors can lead to increased risk of ALRI in children and predispose a child to hospitalisation, but population attributable fractions for different risk factors and how these fractions differ between Indigenous and non-Indigenous children is unknown. This study investigates population attributable fractions of known infant and maternal risk factors for ALRI to inform prevention strategies that target high-risk groups or particular risk factors.

Methods

A retrospective population-based data linkage study of 245,249 singleton births in Western Australia. Population attributable fractions of known maternal and infant risk factors for hospitalisation with ALRI between 1996 and 2005 were calculated using multiple logistic regression.

Results

The overall ALRI hospitalisation rate was 16.1/1,000 person-years for non-Aboriginal children and 93.0/1,000 for Aboriginal children. Male gender, being born in autumn, gestational age <33 weeks, and multiple previous pregnancies were significant risk factors for ALRI in both Aboriginal and non-Aboriginal children. In non-Aboriginal children, maternal smoking during pregnancy accounted for 6.3% (95%CI: 5.0, 7.6) of the population attributable fraction for ALRI, being born in autumn accounted for 12.3% (10.8, 13.8), being born to a mother with three or more previous pregnancies accounted for 15.4% (14.1, 17.0) and delivery by elective caesarean accounted for 4.1% (2.8, 5.3). In Aboriginal children, being born to a mother with three or more previous pregnancies accounted for 16.5% (11.8, 20.9), but remote location at birth accounted for 11.7% (8.5, 14.8), maternal age <20 years accounted for 11.2% (7.8, 14.5), and being in the most disadvantaged socio-economic group accounted for 18.4% (-6.5, 37.4) of the population attributable fraction.

Conclusions

The population attributable fractions estimated in this study should help in guiding public health interventions to prevent ALRI. A key risk factor for all children is maternal smoking during pregnancy, and multiple previous pregnancies and autumnal births are important high-risk groups. Specific key target areas are reducing elective caesareans in non-Aboriginal women and reducing teenage pregnancies and improving access to services and living conditions for the Aboriginal population.

Histological profile of tumours from MYCN transgenic mice

BACKGROUND

MYCN is the most commonly amplified gene in human neuroblastomas. This proto-oncogene has been overexpressed in a mouse model of the disease in order to explore the role of MYCN in this tumour.

AIMS

To report the histopathological features of neuroblastomas from MYCN transgenic mice.

METHODS

27 neuroblastomas from hemizygous transgenic mice and four tumours from homozygous mice were examined histologically; Ki67 and MYCN immunocytochemistry was performed in 24 tumours.

RESULTS

Tumours obtained from MYCN transgenic mice resembled human neuroblastomas, displaying many of the features associated with stroma-poor neuroblastoma, including heterogeneity of differentiation (but no overt ganglionic differentiation was seen), low levels of Schwannian stroma and a high mitosis karyorrhexis index. The tumours had a median Ki67 labelling index of 70%; all tumours expressed MYCN with a median labelling index of 68%. The most striking difference between the murine and human neuroblastomas was the presence of tingible body macrophages in the transgenic mouse tumours reflecting high levels of apoptosis. This has not previously been described in human or other murine neuroblastoma models.

CONCLUSIONS

These studies highlight the histological similarities between tumours from MYCN transgenic mice and human neuroblastomas, and reaffirm their role as a valuable model to study the biology of aggressive human neuroblastoma.

Managing menopause after breast cancer: balancing risks and benefits

Many women now survive breast cancer, but find themselves at increased risk of menopausal complications. How to manage menopause after breast cancer is a complex issue, given that estrogen has a role in the development of breast cancer and valid concerns exist about estrogen replacement therapy in patients who have had breast cancer. This article explores the relationship between estrogens and breast cancer and discusses management options for a variety of menopausal complications in breast cancer survivors.

Breast cancer and pregnancy

A diagnosis of breast cancer during pregnancy or the postpartum period is an unfortunate occurrence. Hormonal factors appear to play an important role early on in the development of breast cancer; however, pregnancy itself does not clearly influence the outcome of an established breast cancer. Diagnosis can be challenging in a pregnant woman and delays in diagnosis are common. Treatment decisions must take into consideration not only toxicity to the mother, but short- and long-term consequences for the fetus as well. Other special considerations with pregnancy-associated breast cancer include the timing of delivery, the potential for nursing, and concerns for future fertility. In general, management of pregnancy associated breast cancer follows the same principals as in non-pregnant patients of similar age. With thoughtful application of available therapies, outcome can be optimized for both the mother and her child.

Fertility and the impact of systemic therapy on hormonal status following treatment for breast cancer

Issues of long-term toxicity from treatment for breast cancer, including the induction of premature ovarian failure, appear to be of increasing importance for breast cancer survivors. The incidence of treatment-related amenorrhea is related to patient age and to the treatment regimen. Whereas the induction of ovarian failure may be advantageous with respect to breast cancer outcome, it is not clear that there is any advantage to permanent menopause over reversible hormonal manipulations. In addition, menopause may be associated with a variety of adverse health effects. Although nonhormonal therapies are available to manage many of the consequences of menopause, avoidance of chemotherapy-related ovarian toxicity may provide the best prospects for fertility after treatment. Pregnancy after breast cancer is a realistic consideration for some breast cancer survivors and is not clearly detrimental to either the mother or her offspring.

Progressive intermediate-grade non-Hodgkin's lymphoma after high-dose therapy and autologous peripheral stem-cell transplantation: changing the natural history with monoclonal antibody therapy

The prognosis of patients with progressive intermediate-grade non-Hodgkin's lymphoma (NHL) after high-dose chemotherapy and autologous peripheral stem-cell transplantation (PSCT) is poor, with survival measured in months. The advent of monoclonal antibody therapy for NHL has created new options for effective therapy with relatively mild side effects. We report on two patients with progressive intermediate-grade NHL after PSCT who were treated with monoclonal antibody therapy. Both patients initially received rituximab (unlabeled anti-CD20 monoclonal antibody) and were subsequently treated with (90)Y-epratuzumab (yttrium-90-labeled humanized anti-CD22 monoclonal antibody) at relapse. One patient received (90)Y-epratuzumab alone while the other was treated with higher doses in combination with autologous peripheral stem-cell infusion. Both patients achieved a rapid response to the radiolabeled antibody with minimal toxicity. Monoclonal antibody therapy may be an effective and tolerable treatment for progressive NHL after PSCT.

Adjuvant therapy of colon cancer

Colon cancer is an important cause of cancer-related mortality. A series of clinical trials of adjuvant systemic therapy have been performed in attempt to establish means to improve outcome in this disease. By the early 1990s, a role for 5-fluorouracil (5-FU)-based chemotherapy in stage III colon cancer had been firmly established. The precise role for chemotherapy in stage II disease remains under investigation. Progress continues toward optimizing the schedule and duration of systemic therapy, allowing for maximal efficacy with a minimum of toxicity. It appears that approximately 6 months of 5-FU and leucovorin are as effective as more prolonged regimens. Levamisole does not appear to add to the benefit of 5-FU and leucovorin. Several newer agents such as the oral fluorinated pyrimidines, irinotecan (CPT-11) and oxaliplatin have demonstrated activity in metastatic colon cancer and hold promise as potentially effective drugs to be tested in the adjuvant setting.

Autologous stem-cell transplant after conventional dose adjuvant chemotherapy for high-risk breast cancer: impact on the delivery of local-regional radiation therapy

BACKGROUND

High-dose chemotherapy with autologous stem-cell transplantation is used increasingly in the treatment of poor-prognosis primary breast cancer. Because these patients may be cured with standard multimodality therapy, it is important to address both the efficacy of transplantation, and its effect on the delivery of standard treatments including local radiation therapy.

PATIENTS AND METHODS

Patients with high risk primary breast cancer were treated with high-dose cyclophosphamide and thiotepa and stem-cell transplant following surgery and conventional-dose adjuvant chemotherapy. Outcome, including sites of failure and delivery of local radiation therapy, was assessed for 103 patients.

RESULTS

Overall and disease-free survival rates at 18 months were 83% (+/- 4%) and 77% (+/- 4%) respectively. Twenty patients (19.4%) received radiation therapy prior to transplant. Of the remaining 83, 77 received radiation therapy after transplant. Overall, 5 (19.2%) of 26 first sites of recurrence were local alone. For patients receiving radiation prior to transplant, 3 of 7 (43%, 95% CI: 6%-80%) sites of first recurrence were local, while 2 of 19 (10.5%, 95% CI: 0%-24.5%) sites of first recurrence were local alone in patients receiving post-transplant radiation or no radiation.

CONCLUSION

Transplantation does not appear to significantly compromise the delivery or outcome of local radiation therapy for primary breast cancer.

Open reduction-fixation of mandibular subcondylar fractures. A review

From 1973 to 1990, 392 mandibular subcondylar fractures were treated at the University of California, Davis, by the Otolaryngology Department. Of these, 17% were handled by open reduction and internal fixation. Twenty-one patients from this group were located for follow-up at an average interval of 64 months. Retrospective review shows the operation to be safe, with few complications and no permanent sequelae. Patient examination often revealed abnormalities of occlusion and mandibular function; however, these objective findings did not correlate well with patients' relative lack of subjective complaints. An 86% incidence of roentgenographic evidence of condylar disease after open reduction and internal fixation was found. We question the long-term efficacy of open reduction and internal fixation in restoring fracture alignment and maintaining mandibular height given the high rate (86%) of condylar disease in our patient population.

Acoustic isolation reduces degeneration of the ventral cochlear nuclei in Mongolian gerbils

The role of auditory experience in the development of spongiform degeneration in the cochlear nuclei of Mongolian gerbils was studied by comparing results of animals exposed to either high or low levels of ambient noise. Gerbils reared in a typical vivarium experienced higher levels of ambient noise than animals reared in acoustic isolation chambers. Animals reared in the colony room showed a much greater number density and area density of spongiform lesions in the CN than did gerbils reared in acoustic isolation. The differences in the number and extent of spongiform lesions between the two groups of gerbils appeared to reflect their differences in exposure to ambient noise. These differences in lesion number and extent were most pronounced in the tonotopic regions of the PVCN which correspond to the greatest differences in the spectral characteristics of the ambient noise to which the animals were exposed. These results were compared with results previously obtained from gerbils with loss of hearing experimentally induced by a conductive block or by sensorineural damage. The lesion numbers and extent reflected the auditory experience of each group; in descending order, colony-reared, isolate, conductive-block, sensorineural loss. These results strongly support the hypothesis that this gerbilline encephalopathy is directly related to auditory functional activity.

Effects of profound sensorineural loss on gerbilline auditory encephalopathy

To investigate the role of acoustic stimulation in the development of spongiform degeneration in the cochlear nuclei of Mongolian gerbils, the right cochlea in 8 juvenile gerbils was chemically treated by placing sodium chloride (NaCl) crystals on the cochlear round window membrane. Sixty days after NaCl treatment there was extensive damage to the strial, sensorineural and supporting cells of the treated inner ear. The cochlear damage was accompanied by a dramatic decrease in the number and the extent of the spongioid lesions in the ipsilateral cochlear nuclei compared to the contralateral (control) cochlear nuclei. These results lend further support to the hypothesis that the progress of this disorder is related to auditory function.

Linear localized coumarin necrosis

We report a 55-year-old man with coumarin necrosis. This drug eruption is sometimes a devastating gangrenous process in sites with abundant underlying adipose tissue. In our patient, however, it assumed an evanescent limited linear distribution on the skin, prompting this report.

Use of a low-ionic-strength medium in manual tests for antibody detection

The present observations confirm the value of suspending red blood cells in a low-ionic-strength medium in the first stage of the indirect antiglobulin test; that is, during the period of incubation with antibody-containing serum. The main advantage of this procedure is to shorten the time of incubation. In this respect a low-ionic-strength medium appears to be superior to albumin as a suspending medium for the red blood cells. A further advantage is to increase the uptake of certain antibodies; this effect was pronounced with selected Rh antibodies believed to be of low affinity.

Successful transfusion of Chido-positive blood to two patients with anti-Chido

Two cases are described in this report in which patients with anti-Chido in the serum were transfused with Chido-positive blood. Since there was evidence of normal survival of the transfused red blood cells, these findings do not support a suggestion that patients with anti-Chido may require transfusion with Chido-negative blood. In spite of the apparently normal survival of the Chido-positive blood, a previous report in which it was shown that weakly Chido-positive blood can stimulate the production of anti-Chido was confirmed.

The effect of foetal removal on the blood pressure in steroid hypertensive rats

In unilaterally nephrectomized hypertensive rats receiving DOCA, cortisone and saline the blood pressure falls after the removal of the foetuses as though the animals continued to be pregnant with the foetuses in situ. On the other hand, when the foetuses are removed from steroid hypertensive animals in which the maternal kidneys remain intact the blood pressure remains at hypertensive levels. The metrial gland part of the placenta appears histologically viable after foetal removal.

We conclude from the present and earlier experiments that the usual hypotensive effect of pregnancy in hypertensive animals is due to a vasodepressor agent produced by the foetuses and the metrial gland moiety of the placenta and that the activity of this agent is subject to maternal renal function.

A relation between these experiments and human pregnancy hypertension is not clear but we suggest that in human pregnancy, hypertension could be due either to failure of the foetoplacental vasodepressor or vasodilator agent or to destruction or excretion of this agent by the maternal kidney.

The duration of the fall of blood pressure following the induction of deciduomata and the administration of progesterone in steroid hypertensive rats

Experimental deciduomata produce a protracted fall of blood pressure in steroid hypertensive rats. The fall begins at between 9 and 13 days of pseudopregnancy, lasts for between 8 and 14 days and is then followed by a restoration to higher levels between 17 and 24 days. The metrial gland of the deciduomata is thought to be responsible for the fall.

Parenteral progesterone has two main effects. It enhances the degree of the fall of blood pressure and also prolongs the survival of deciduomata to beyond 22 days of pseudopregnancy. Progesterone does not alter the time of onset nor the duration of the hypotensive episode and the return of the blood pressure to higher levels takes place even though the metrial gland of the deciduomata is still viable and progesterone still being administered.

It is considered that the duration of the hypotensive episode is determined either by a changed function of the metrial gland cells with duration or to an entirely different but unknown mechanism.

The present findings suggest that the hypotensive effect of pregnancy in hypertensive rats is a related phenomenon and is due in part to the function of metrial gland cells of the pregnancy decidua under the influence of progesterone.

The fall of blood pressure following induction of deciduomata in steroid hypertensive rats receiving progesterone

Experimental deciduomata and progesterone together lower the blood pressure in the steroid hypertensive rat from the 5th to 10th day of decidual growth i. e. from the 10th to 15th day of pseudopregnancy. This would suggest that the fall of blood pressure at an equivalent time of gestation in hypertensive pregnant rats could be due to the maternal decidua under the influence of progesterone. It is further considered that the metrial gland of the deciduoma is more likely to be responsible for the hypotensive effect and by comparison that the metrial gland is implicated in the hypotensive effect of pregnancy.

Progesterone alone also exerts a minor hypotensive effect in those animals in which a nephrectomy forms part of the hypertension regimen and indicates one way in which a maternal renal factor could influence blood pressure responses in hypertensive pregnant rats.

Effect of the experimental deciduoma on steroid hypertension in the rat

Experimental deciduomas which are maintained for 5 to 6 days do not lower the blood pressure in steroid hypertensive rats. In animals maintained longer only the metrial gland of the deciduoma survives but this too does not have a hypotensive action.

It is concluded that the maternal decidual reaction in pregnant hypertensive rats is not responsible for the fall of blood pressure when this occurs at an equivalent time of gestation of up to 10 or 11 days and that the metrial gland is not responsible for the fall of blood pressure at whatever time the fall occurs during gestation.