Improved methods of assessing proteinuria in hypertensive pregnancy

OBJECTIVE

To determine whether use of an automated urinalysis device will improve the accuracy of detecting proteinuria, and whether spot urine protein to creatinine ratio will provide accurate quantitation of proteinuria in hypertensive pregnant women.

DESIGN

Prospective studies assessing the accuracy of both detection and quantitation of proteinuria.

SETTING

Antenatal ward and pregnancy day assessment unit of St George Hospital, a teaching hospital in Sydney, Australia.

POPULATION

Hypertensive pregnant women admitted to hospital or day assessment unit for management of their hypertensive disorders.

METHODS

1. Routine dipstick urinalysis and 2. urinalysis by an automated device (Clinitek 100 Ames) on a midstream urine sample were compared with measurement of protein concentration on that sample (n = 103). In a third study, the protein:creatinine ratio on a midstream (spot) urine sample was compared with protein excretion over the subsequent 24 hours (n = 100).

MAIN OUTCOME MEASURES

Relations between urine protein concentrations and 1. dipstick urinalysis and 2. automated urinalysis; 3. Positive and negative predictive values of spot protein:creatinine ratio for true proteinuria (> or = 300 mg/day).

RESULTS

Automated urinalysis improved the percentage of true positive urinalyses from 48% with visual urinalysis to 74% (P = 0.02). True negatives were 98% to 100% for both methods. Spot urine protein:creatinine ratio correlated well with subsequent 24-hour urine proteinuria (r = 0.93, P < 0.001). A protein:creatinine ratio > 30 mg protein/mmol creatinine was the optimum discriminant value for true proteinuria, with sensitivity 93%, specificity 92%, positive predictive value 95% and negative predictive value 90%.

CONCLUSIONS

Use of an automated urinalysis device improved accurate detection of proteinuria, particularly reducing false positive tests. A random urine protein:creatinine ratio provides an accurate and rapid quantitation of proteinuria in hypertensive pregnant women. This should improve clinical care, especially when managing hypertensive pregnant women as outpatients.

Extraneous lipid contamination in single-volume proton MR spectroscopy: phantom and human studies

PURPOSE

To determine the degree of extraneous lipid contamination in defined volumes of interest studied with single-volume proton MR spectroscopy.

METHODS

Single-volume proton MR spectroscopy was performed on a fat/water phantom and in three volunteers using the stimulated-echo acquisition mode (STEAM) and point-resolved spectroscopy (PRESS) localization methods. Three different volumes of interest (8, 27, and 64 cm3) were examined at echo times of 20, 135, and 270 for the STEAM sequences and 135 and 270 for the PRESS acquisitions in both the phantom and the volunteers (volumes of interest were placed adjacent to but not encompassing fat-containing structures, such as the scalp and retroorbital fat). The degree of lipid contamination was then correlated with measurements of the section profiles.

RESULTS

The PRESS method resulted in less extraneous lipid contamination in both phantom and volunteer studies. The STEAM method had the highest level of lipid contamination signal in phantom and human studies. In the volunteers, volumes of interest abutting fat-containing structures obtained with PRESS or STEAM sequences showed no lipid contamination. However, the STEAM sequences showed lipid signal in the volume of interest adjacent to orbital fat whereas the PRESS sequences did not. These observations are supported by the section profile studies, which showed that the actual volume excited by the STEAM sequence was 7% to 32% larger than that originally selected, while with PRESS the actual excited volume was 12% to 16% smaller than that originally selected.

CONCLUSION

In our MR unit, short-echo-time STEAM sequences (< or = 135 milliseconds) resulted in extraneous lipid contamination in phantom and human studies adjacent to the orbits. PRESS sequences showed no lipid contamination in volumes abutting fat structures in phantoms or humans. These results correlated closely with the configuration of the section profiles. Although these findings might be dependent on the MR unit used, our study could help determine extraneous lipid contamination for other MR units.

Measuring venous capacitance and blood flow in pregnancy

Forearm or calf venous plethysmography has been used in pregnant women to examine the effects of pregnancy on the vascular system and more recently to measure blood flow changes in response to intra-arterial infusion of vasoactive substances. To examine the assumption that venous capacitance and blood flow measurements are the same in the forearm and calf, venous plethysmography was conducted simultaneously on the forearm and calf in normal (NP) and hypertensive pregnant women (HTP) in their third trimester and in normal nonpregnant women (N). All studies were made on the right forearm and calf with subjects in the left lateral recumbent position. There was no significant difference between venous capacitance in the forearm (median: 124 x 10(3)mL/100mL/mmHg for both NP and HTP) and leg (134 [NP] and 106 [HTP] x 10(3)mL/100mL/mmHg) for both pregnant groups but venous capacitance in the nonpregnant group was greater in the leg than arm (174 versus 112 x 10(3)mL/100mL/mmHg, p < 0.001). Blood flow was similar in the leg and forearm (median 4.9 versus 3.9mL/100mL/min respectively) in nonpregnant women. Forearm blood flow was also similar to calf flow in NP women (6.2 versus 4.3mL/100mL/min respectively) but greater than calf blood flow in HTP (9.7 versus 5.3mL/100mL/min, p < 0.01). Using left lateral recumbency, forearm and calf vein capacitances are similar in pregnant women, in contrast to nonpregnant women. Blood flow is higher in the forearm than the calf only in hypertensive pregnant women. These observations should be borne in mind when interpreting studies of regional blood flow in pregnancy.

Second Australian National Blood Pressure Study (ANBP2). Australian Comparative Outcome Trial of ACE inhibitor- and diuretic-based treatment of hypertension in the elderly. Management Committee on behalf of the High Blood Pressure Research Council of Australia

The Second Australian National Blood Pressure Study (ANBP2) is a comparative outcome trial being conducted in general practices throughout Australia of ACE inhibitor- and diuretic-based treatment in 6000 hypertensive patients aged 65-84 years. The study is using a prospective randomised open-label design with blinding of endpoint assessments. The primary objective is to determine whether there is any difference in total cardiovascular events (fatal and non-fatal) over a five year treatment period between the two treatment regimens. Eligible hypertensive patients (average sitting blood pressure at the 2nd and 3rd screening visits > 160 mm Hg systolic and/or > 90 mm Hg diastolic) may be either untreated or previously treated and should have no history of recent cardiovascular morbidity or serious intercurrent illness. Patients are randomised to one of the treatment arms with randomisation stratified for practice and for age. Following randomisation each patient's blood pressure is managed by his/her general practitioner according to guidelines relevant to each treatment arm. Over 700 patients have now been randomised with recruitment intended to be complete by the end of 1997.

The renin-angiotensin-aldosterone system in pre-eclampsia

Pre-eclampsia is characterised physiologically by plasma volume contraction, intravascular coagulation and intense vasoconstriction. It was originally thought that the renin-angiotensin-aldosterone (RAA) system would be overactive but studies have shown a more complex picture. Plasma renin activity (PRA) and concentration (PRC) and plasma angiotensin II (AII) and aldosterone concentrations (PAC) are reduced compared to normal pregnancy. Total renin concentration is normal and plasma concentrations of high molecular weight angiotensinogen are increased in pre-eclampsia though total angiotensinogen is normal. PRA and PRC respond appropriately to physiologic stimuli in pre-eclampsia except for impaired renin release following frusemide, possibly due to prostacyclin deficiency. Although plasma AII concentrations are reduced there is heightened pressor sensitivity to infused AII--the mechanism(s) for this are unknown. PAC is reduced but the ratio PAC-PRC is twofold greater in pre-eclampsia than normal pregnancy. This does not appear to be due to changes in potassium, atrial natriuretic peptide, dopamine or ACTH, and may be another manifestation of increased (adrenal) sensitivity to AII in pre-eclampsia. There is an inverse relationship between the plasma active renin to prorenin ratio and the clinical severity of the pre-eclampsia. Understanding the mechanisms producing these changes in the RAA system in pre-eclampsia will give strong clues to the overall pathogenesis of this disorder.

Glucocorticoids and hypertension in man

Abnormalities of cortisol production or metabolism are involved in the genesis of hypertension in Cushing's syndrome, apparent mineralocorticoid excess and liquorice abuse and possibly in chronic renal failure and essential hypertension. We have studied the physiological mechanisms by which cortisol raises blood pressure in short term studies of cortisol administration in normal men. Cortisol induced hypertension cannot be explained by increases in vasopressor or decreases in vasodepressor hormone concentrations, or by any increase in sympathetic nervous activity. The hypertension is accompanied by substantial sodium retention but a significant component of the blood pressure rise is sodium independent. The hypertension is characterized by an increase in cardiac output but a rise in output is not essential for the rise in blood pressure. Our working hypothesis is that cortisol induced hypertension is a consequence of increases in renal vascular resistance.

The effects of hair density of beef cattle on Haematobia irritans horn fly populations

We show the relationships that exist between the amount of hair and quantity of sebum on cattle skin and the population density of the horn fly, Haematobia irritans. Brahman and Chianina steers had means of 2390 and 1587 hairs per cm2, respectively, significantly more than the mean number of hairs on Angus, Brahman x Angus Crossbred, Charolais, and Red Poll steers. The Chianina steers had > 30% more sebum present on their skin and hair (0.58g/929 cm2) than the Angus, Charolais, and Red Poll steers at the Beef Cattle Research Station Savoy, Arkansas. The Brahman steers had a significantly greater amount of sebum present on the skin (1.51 g/929 cm2) than the Crossbred and purebred Angus steers (0.55 and 0.25 g/929 cm2, respectively) at the South Central Family Farms Research Centre Booneville, Arkansas. The Brahman and Chianina steers had means of 61.9 and 17.0 horn flies per steer, respectively, during the fly season, whereas the Angus, Crossbred, Charolais and Red Poll steers had fly season means that ranged from 76.9 to 265.8 flies per steer. Regression analysis showed that an increase of 100 hairs per cm2, was associated with a reduction of 11 horn flies in the Angus II, 5 in Angus I, 20 in Charolais, 37 in Red Poll, and 0.4 in Chianina steers at the Savoy Station and a reduction of 6.6 horn flies for the Angus, Brahman, and Crossbred steers at the Booneville Centre. Regardless of cattle breed, an increase of 1.0 g of sebum per 929 cm2 output by the steer was associated with 478.5 additional hairs per cm2 on the animal. Each increase of 0.25 g of sebum per 929 cm2 resulted in a decrease of 9.2 horn flies per steer. We conclude that some of the factors responsible for fly-resistance in cattle are hair density and the corresponding amount of sebum present on cattle skin and hair.

Isolation and characterisation of the NBR2 gene which lies head to head with the human BRCA1 gene

To study the regulation of BRCA1 gene expression and the potential importance of dysregulation of this gene in breast and ovarian cancer, we have examined the 5' region of the human BRCA1 gene in detail. We have identified a new gene, NBR2, which is partially related to the NBR1 gene (formerly known as 1A1-3B and mapping directly adjacent to the pseudo-BRCA1 gene) and which lies head to head with the BRCA1 gene. The physical distance between the transcription start sites of the NBR2 and BRCA1 genes is 218 bp, suggesting that regulation of the expression of both genes may be co-ordinated through a bi-directional promoter. The NBR2 gene contains five exons spanning a genomic region of approximately 30 kb between the BRCA1 and pseudo-BRCA1 genes. Northern analysis showed that the NBR2 gene is expressed in all the tissues examined. The NBR2 cDNA contains an open reading frame of 112 amino acids and is predicted to encode a protein of approximately 12 kDa. Single-strand conformation polymorphism (SSCP) analysis of the NBR2 gene failed to identify any mutations in either breast or ovarian cancer, suggesting that if the NBR2 gene is involved in the development of these cancers, other mechanisms for tumorigenesis may exist. Hybridisation of NBR2 probes to zoo blots showed that the NBR2 gene is present in human and other primates. No hybridisation to DNA from other species was observed, suggesting that genomic elements controlling BRCA1 expression may differ between species.

Withdrawal of nifedipine capsules: jeopardizing the treatment of acute severe hypertension in pregnancy? Australasian Society for the Study of Hypertension in Pregnancy

Short-acting oral nifedipine has been withdrawn from the Australian market because of reports of its adverse effects after long-term treatment in non-pregnant patients with heart disease. This will have a major impact on the treatment of acutely hypertensive pregnant women, in whom the drug has proven to be safe, effective and easy to administer. Should pregnant women be forced to use less suitable agents, thus threatening their own and their babies' health?

Effects of diet on measurement of nitric oxide metabolites

1. The present study investigated whether a low nitrate/nitrite diet could minimize variability in the measurement of endogenous plasma and urine nitric oxide (NO) metabolites, nitrate and nitrite (NOx) in normal subjects. 2. Nitrate and nitrite concentrations were measured in plasma and urine as indicators of NO production in six subjects during a free diet and then during a low nitrate/nitrite diet for 6 days. 3. The plasma concentration and 24 h urine NOx/creatinine ratio were significantly lower on the low nitrate/nitrite diet than on the free diet (P < 0.01). Nitric oxide production appeared to vary greatly within and between subjects, but these variations were substantially decreased by the fourth day of a low nitrate/nitrite diet. 4. Human plasma and urine NOx measurements should be determined after a low nitrate/nitrite diet for at least 4 days.

Purification, partial characterization and peptide sequences of vitellogenin from a reptile, the tuatara (Sphenodon punctatus)

Vitellogenin (Vg), a major precursor to egg yolk proteins, was purified from plasma of an estradiol-treated female tuatara (Sphenodon punctatus) by MgCl2-EDTA precipitation and DEAE-cellulose chromatography. The amino acid composition of tuatara Vg is similar to that of other vertebtate Vgs and contains a large proportion of serine (13.7 mol/100 mol of total amino acid). The amino acid sequences of the N-terminus of mature Vg (33 residues) and of several trypsin- and CNBr-generated peptides were determined. Six peptide sequences obtained from tuatara Vg could be aligned with Vg sequences from other vertebrates. Reduced and non-reduced forms of tuatara Vg have the same apparent molecular mass (approximately 218 kDa) when resolved by SDS-PAGE, indicating that inter-chain disulfide bonds are not a feature of the molecule in this species. Western blot analysis with anti-tuatara Vg antiserum indicated that at least some epitopes are shared among Vgs of turtle, alligator and tuatara.

Feasibility of conducting cardiovascular outcome research in Australian general practice: results from the ANBP2 pilot study. Australian National Blood Pressure Study

1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was > or = 160 mmHg systolic or > or = 90 mmHg diastolic if systolic BP was > or = 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82,000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP > or = 160/90 mmHg. Forty-seven per cent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.

Studies on inherited cancers: outcomes and challenges of 25 years

Research on the dominantly inherited cancer-susceptibility syndromes over the past 25 years has defined the genetic basis of most of these diseases, usually through linkage analysis on families carrying the disease, and identification and analysis of the genes responsible. At present, almost all of these genes have been cloned and, in most cases, the findings have lent full support to Knudson's original hypothesis: germline carriers of mutations in cancer susceptibility genes are predisposed to developing cancer, the resultant tumours contain aberrations in the remaining copy of that gene, and these genes often play a pivotal role in the genesis of the equivalent sporadic cancers, whereby two somatic events result in the disruption of both copies of the gene. This perspective highlight some of the issues that have been raised by these studies, and points to a few of the areas of future research that might help to resolve them.

The role of the hypothalamic-pituitary-adrenal (HPA) axis in the regulation of blood pressure

The role of the HPA axis in blood pressure regulation was examined in 6 normal male volunteers by comparing haemodynamic and hormonal effects of placebo, captopril, and dexamethasone given in random order for two days. The average 24-hour systolic and mean arterial pressures on placebo (135 +/- 6 and 93 +/- 2 mmHg respectively) were significantly higher than on captopril (118 +/- 1 and 85 +/- 1 mmHg respectively, p < 0.05) but there were no significant changes on dexamethasone compared with placebo (128 +/- 3 and 89 +/- 3 mmHg respectively). There were no differences in the average 24-hour diastolic blood pressures or heart rates, nor the day-night differences, night:day ratios or percentage changes in blood pressure and heart rate between treatments. Captopril significantly increased active plasma renin concentration, whilst dexamethasone decreased cortisol concentration. These results confirm the role of the renin-angiotensin system in the regulation of blood pressure in normal subjects but suggest that the HPA axis does not play a major role in determining ambulatory blood pressure or day-night variability in the short term.

Genotype x environment interactions in Angus, Brahman, and reciprocal cross cows and their calves grazing common bermudagrass and endophyte-infected tall fescue pastures

Reproductive and preweaning data on 233 Angus (A), Brahman (B), and reciprocal-cross cows (AB, BA) and 455 two- and three-breed cross calves managed on common bermudagrass or endophyte-infected tall fescue were used to evaluate the interaction of forage type with individual and maternal heterosis and maternal and grandmaternal breed effects. Cows were born from 1988 to 1991 and calves from 15 Polled Hereford sires were born from 1991 to 1994. Heterosis for calving rate was similar and important on both forages (P < .01), but maternal effects were small on each forage. Maternal heterosis for birth weight differed between common bermudagrass and tall fescue (P < .10) and grandmaternal effects were evident on bermudagrass (P < .05) but not tall fescue. Forage effects were generally substantial for 205-d weight, weaning hip height, and weaning weight:height ratio (P < .01), and maternal heterosis for these traits was larger on tall fescue than on common bermudagrass (P < .01). Grandmaternal effects were in favor of Angus for 205-d weight, hip height, and weight:height ratio on common bermudagrass (P < .05) but not on tall fescue. Heterosis for 205-d weight per cow exposed was substantial on both forages (P < .01) and was numerically larger on tall fescue than on bermudagrass, but maternal effects were not significant. These results suggest more advantage for Brahman-cross cows over purebreds on endophyte-infected tall fescue than a similar comparison on common bermudagrass. They also suggest an advantage for Angus in grandmaternal effects on bermudagrass but not tall fescue.

Cloning, isolation, and characterization of mammalian legumain, an asparaginyl endopeptidase

Legumain is a cysteine endopeptidase that shows strict specificity for hydrolysis of asparaginyl bonds. The enzyme belongs to peptidase family C13, and is thus unrelated to the better known cysteine peptidases of the papain family, C1 (Rawlings, N. D., and Barrett, A. J. (1994) Methods Enzymol. 244, 461-486). To date, legumain has been described only from plants and a blood fluke, Schistosoma mansoni. We now show that legumain is present in mammals. We have cloned and sequenced human legumain and part of pig legumain. We have also purified legumain to homogeneity (2200-fold, 8% yield) from pig kidney. The mammalian sequences are clearly homologous with legumains from non-mammalian species. Pig legumain is a glycoprotein of about 34 kDa, decreasing to 31 kDa on deglycosylation. It is an asparaginyl endopeptidase, hydrolyzing Z-Ala-Ala-Asn-7-(4-methyl)coumarylamide and benzoyl-Asn-p-nitroanilide. Maximal activity is seen at pH 5.8 under normal assay conditions, and the enzyme is irreversibly denatured at pH 7 and above. Mammalian legumain is a cysteine endopeptidase, inhibited by iodoacetamide and maleimides, but unaffected by compound E64 (trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane). It is inhibited by ovocystatin (cystatin from chicken egg white) and human cystatin C with Ki values < 5 nM. We discuss the significance of the discovery of a cysteine endopeptidase of a new family and distinctive specificity in man and other mammals.

Taking care: caregiving to persons with cancer and AIDS

The purpose of this study was to provide an in-depth description of Taking Care, one of the phases of a grounded theory (The Labor of Caregiving) of caregiving for families experiencing life-threatening illnesses such as cancer and acquired immune deficiency syndrome (AIDS). In-depth interviews were conducted with 26 family caregivers of persons with cancer and AIDS during a 4-month period. Grounded theory methodology served as the basis for data collection and analysis. Data were analyzed in terms of the strategies, consequences, and interactions involved in the caregiving experience. The strategies of Taking Care included these data themes: Managing the Illness, Facing and Preparing for Dying, and Managing the Environment. The consequences of Taking Care included the data themes Coming to Know One's Own Strength, and Personal Suffering. Interactions that occurred as a result of Taking Care included Responding to Family Relationship Issues, and Struggling with the Health Care System. Findings from this research reveal that family caregivers dedicate an enormous portion of their lives to caring for their ill family members. They experience their own form of suffering as they watch their loved one die. Some also find personal meaning in the experience and an awakening of their own strengths. One of the implications from these findings is the need for a partnership between health care professionals and the families providing care.

Mutations and alternative splicing of the BRCA1 gene in UK breast/ovarian cancer families

BRCA1 is a tumour suppressor gene located on chromosome band 17q21. It is estimated that mutations in the BRCA1 gene account for approximately 45% of the breast cancer families and almost all of the breast/ovarian cancer families. We have used single strand conformation polymorphism analysis, direct sequencing, allele specific oligonucleotide hybridisation, and reverse transcription polymerase chain reaction (RT-PCR) to look for mutations in the BRCA1 gene in 49 breast or breast/ovarian cancer families. Five distinct mutations, three novel and two previously observed, were detected in seven families. Each novel mutation was identified in one family: 3896delT in exon 11, a splicing mutation in the intron 9-exon 10 junction, and an inferred regulatory mutation. The 185delAG in exon 2 was found in three families sharing the same haplotype, but this haplotype is different from that shared by the Ashkenazi Jewish families, suggesting that the 185delAG in our families may have arisen independently. Another previously reported mutation, the 3875del4 in exon 11, was identified in one family. Of the 49 families examined, linkage analyses for both the BRCA1 and the BRCA2 regions were performed on 33 families, and mutations in the BRCA1 gene were identified in all but one family that have a lod score above 0.8 for BRCA1. All of the mutations cause either a truncated BRCA1, or loss of a BRCA1 transcript, thus are likely to be functionally disruptive. In addition, we found that alternative splicing is a common phenomenon in the processing of the BRCA1 gene. Seven variant BRCA1 transcripts were identified by RT-PCR; all but one maintained the BRCA1 open reading frame. We believe that alternative splicing may play a significant role in modulating the physiological function of BRCA1.

Functions of IL-4 and control of its expression

IL-4 has been called the "prototypic immunoregulatory cytokine." Like many cytokines, it can affect a variety of target cells in multiple ways. IL-4 has an important role in regulating antibody production, hematopoiesis and inflammation, and the development of effector T-cell responses. It is produced only by a subset of activated hematopoietic cells, including T cells and Fc epsilon R1+ mast cells and basophils. Based on the different tissue distribution and access to distinct target cells, IL-4 derived from T and Fc epsilon R1+ cells may have quite different effects on these immunological processes. In view of this, as well as the clear correlation of aberrant expression with disease, it is of interest to understand the signals that regulate IL-4 expression in a cell-specific manner. Recently, progress has been made in defining the T-cell- and Fc epsilon R1-receptor-mediated signals that stimulate IL-4 gene expression. These studies have demonstrated that there are common and cell-specific signaling pathways that regulate production of this cytokine. In this review, we summarize the activities of IL-4 defined both in vitro and in vivo and compare the signals leading to IL-4 expression in cells of both T- and mast-cell lineage.