On discriminating and not discriminating between affect and representation

The topic involves two issues. They can be related either to different clinical pictures or to divergent opinions about the same clinical facts. But the above mentioned opposition can be found in Freud's work. Listening in analysis differentiates between situations where the distinction of affect and representation is blurred within the general frame of communication and others where this distinction imposes itself because of the critical or chronic character of the predominance of affect. Problems about the discrimination between affect and representation in the unconscious are elucidated in the light of their structural differences. The notion of the psychical representative of the drive announces the reference to the further notion of instinctual impulse. Later on, in Freud's theory, the notion of instinctual impulse has encompassed the distinction between affects and representation. Contemporary authors have, in their vast majority, chosen to refer preferably to object relationships. Nevertheless, the problems raised by Freud remain unanswered. It is with the clinical picture of borderline personality disorders that the lack of discrimination between affect and representation becomes evident. A detailed description is presented of the forms of transference where the irrepresentable prevails, accompanied by feelings of being overwhelmed, repetition compulsion, acting out and somatic reactions. In the countertransference, the affects of helplessness, despair and even the impossibility of grasping the meaning of the patient's communication are frequently met in the analyst. In these clinical pictures, intermediary formations, i.e. psychic organisations where primary processes structures the unconscious, are impaired. One is struck by the limitation of the capacities of representation and by the importance of phenomena related to negative hallucinations specially focused on thought processes, The communication is frequently self-contradictory, the transference oscillating between disembodiment and primitive fusion. The object has a paradoxical status; it is at the same time everything and nothing, the transference being incomprehensible and unanalysable. Different hypotheses are presented to explain the importance of destruction. Finally, the author presents a hypothesis for the deficiency of these intermediary formations because of the absence of continuing cathexis from the primary object at certain important moments of the relationship. It is the establishment of theses intermediary formations that will permit the acceptance of the separation from the object, the child now being able to rely on his own internal creations. However important the influences of the relationship to the other in the genesis of affects, the internal orientation towards the body of the psychic processes is what constitutes the core of the primordial psychic world.

Public sector hospitals and organizational change: an agenda for policy analysis

An important feature of health care systems in recent years is the change in the organizational position and relations of public sector hospitals. Health sector reforms have led to increasing heterogeneity in the organizational location and status of public sector hospitals and new organizational forms of public-private relations are being developed by and for hospitals. These changes can have important implications for health and health care. They raise issues around equity, control, accountability and performance of health care. Yet the policy process in practice may be failing to develop and implement appropriate forms of policy formulation on health sector reform. This paper focuses on the organizational position and relations of hospitals within public sector health services. It firstly outlines key elements of health sector reform and relates these to two dimensions of organizational change for hospitals: increasing heterogeneity and forms of public-private relations. The paper provides a descriptive format for classifying forms of hospital organizational change and proposes a framework of six questions for analysing these organizational forms. This may be used to assess the appropriateness of specific policies to particular country situations and to develop more open debate around hospital organizational forms.

Biochemical monitoring of treatment for galactosaemia: biological variability in metabolite concentrations

Red cell galactose 1-phosphate (Gal-1-P) concentrations and urinary galactitol excretion have been suggested as biochemical indices of dietary compliance in classical transferase-deficient galactosaemia. We report our experience of measuring both in 32 patients over 0-10.9 years (median 3.45). A total of 438 blood specimens for Gal-1-P and 383 urine specimens for galacitol assay were received; 317 pairs of specimens were collected at the same time. Concentrations of both analytes fell rapidly over the first 2-3 months following dietary intervention, to mean (geometric SD) levels of 225 (1.60) mumol/L red cells for Gal-1-P and 388 (1.19) mumol/mmol creatinine for galactitol. Concentrations then fell exponentially over the next 7-8 years, with times to half-disappearance of 6.3 years for Gal-1-P and 6.4 years for galactitol, to levels of 104 (1.58) and 193 (1.36) respectively in patients aged over 10 years. Concentrations of both analytes were independent of the presence of the common Q188R mutation. Mean intra- and inter-individual coefficients of variation (CV) across the range of values studied were 36% and 61% for Gal-1-P, and 37% and 42% for galactitol. Analytical CVs were 3.6% for Gal-1-P and 5.5% for galactitol, indicating that the major source of variability is biological. The correlation coefficient between Gal-1-P and galactitol in paired samples overall was 0.33; the regression equation being [Galactitol] = 0.84[Gal-1-P] + 176. Serial measurements of both Gal-1-P and galactitol may be valuable in monitoring galactosaemia, but high intra-individual biological variability limits their usefulness. Standardization of sample collection times may improve this. Further work is needed to assess the predictive values of both analytes for long-term outcome.

Tumor necrosis factor alpha stimulates lipolysis in adipocytes by decreasing Gi protein concentrations

Prolonged treatment (12-24 h) of adipocytes with tumor necrosis factor alpha (TNFalpha) stimulates lipolysis. We have investigated the hypothesis that TNFalpha stimulates lipolysis by blocking the action of endogenous adenosine. Adipocytes were incubated for 48 h with TNFalpha, and lipolysis was measured in the absence or presence of adenosine deaminase. Without adenosine deaminase, the rate of glycerol release was 2-3-fold higher in the TNFalpha-treated cells, but with adenosine deaminase lipolysis increased in the controls to approximately that in the TNFalpha-treated cells. This suggests that TNFalpha blocks adenosine release or prevents its antilipolytic effect. Both N6-phenylisopropyl adenosine and nicotinic acid were less potent and efficacious inhibitors of lipolysis in treated cells. A decrease in the concentration of alpha-subunits of all three Gi subtypes was detected by Western blotting without a change in Gs proteins or beta-subunits. Gi2alpha was about 50% of control, whereas Gi1alpha and Gi3alpha were about 20 and 40% of control values, respectively. The time course of Gi down-regulation correlated with the stimulation of lipolysis. Furthermore, down-regulation of Gi by an alternative approach (prolonged incubation with N6-phenylisopropyl adenosine) stimulated lipolysis. These findings indicate that TNFalpha stimulates lipolysis by blunting endogenous inhibition of lipolysis. The mechanism appears to be a Gi protein down-regulation.

CDKN2A variants in a population-based sample of Queensland families with melanoma

BACKGROUND

Mutations in the CDKN2A gene confer susceptibility to cutaneous malignant melanoma (CMM); however, the population incidence of such mutations is unknown. Polymorphisms in CDKN2A have also been described, but it is not known whether they influence melanoma risk. We investigated the association of CDKN2A mutations and polymorphisms with melanoma risk in a population-based sample of families ascertained through probands with melanoma.

METHODS

The 482 Queensland, Australia, families in our sample were characterized previously as having high, intermediate, or low family risk of CMM. Unrelated individuals (n = 200 families/individuals) drawn from the Australian Twin Registry served as control subjects. For individuals in the high-risk group, the entire CDKN2A gene coding region was screened for mutations by use of the polymerase chain reaction, agarose gel electrophoresis, allele-specific oligonucleotide (ASO) hybridization, and single-strand conformation polymorphism analysis. The intermediate- and low-risk families and control subjects were analyzed by ASO hybridization for a total of six recurring mutations as well as for polymorphisms at nucleotides (Nts) 442, 500, and 540.

RESULTS

CDKN2A mutations were found only in the high-risk families (nine [10.3%] of 87). The prevalence of the Nt500G (guanosine) polymorphism increased linearly with increasing familial risk (two-sided P = .02) and was highest in the nine (primarily Celtic) families with CDKN2A mutations. After adjustment for ethnic origin, the relationship between risk group and the frequency of the Nt500G allele was weakened (P = .25); however, there was no relationship between ethnic origin and Nt500-polymorphism frequency among the control subjects.

CONCLUSIONS

CDKN2A mutations are rare in this population (approximately 0.2% of all melanoma cases in Queensland) and appear to be associated with melanoma in only the most affected families. The Nt500G allele appears to be associated with familial risk, but this association probably reflects Celtic ancestry.

A case-control study of melanomas of the soles and palms (Australia and Scotland)

OBJECTIVES

Because the factors that influence risk of acral melanomas on the soles and palms in White populations are unknown, we investigated these in a multi-center case-control study.

METHODS

Cases of melanoma of the feet and hands diagnosed from 1987-93 in persons aged over 18 years were ascertained in eastern Australia and western Scotland. There were 275 cases of melanoma on the soles and palms matched to 496 controls (selected from the electoral roll) in Australia, and 36 cases matched to 72 controls (nominated by general practitioners) in Scotland.

RESULTS

Acral melanoma was strongly associated with high total body nevus counts (adjusted relative risk [RR] = 6.3, 95% confidence interval [CI] = 2.5-15.6), and with nevi on the soles (RR = 7.5, CI = 3.0-18.6). There were also significant positive associations with a penetrative injury of the feet or hands (RR = 5.0, CI = 3.0-8.6) and with heavy exposure to agricultural chemicals (RR = 3.6, CI = 1.5-8.3). Sun-sensitive complexions, cumulative sun exposure and a past history of nonmelanoma skin cancer were also associated with increased risk of acral melanoma. Current cigarette smoking was inversely related to acral melanoma (RR = 0.6, CI = 0.4-0.9).

CONCLUSIONS

Melanomas of the soles and palms resemble other cutaneous melanomas in their association with sun exposure, but are distinguished from them by their strong positive associations with nevi on the soles, previous penetrative injury, and exposure to agricultural chemicals, and by their inverse association with smoking.

Photobiological aspects of sunscreen re-application

A single application of a high sun protection factor (SPF) sunscreen has been shown to prevent sunburn, but the existence of a further protective effect following re-application of sunscreen has received little attention. The aim of this study was to quantify the ultraviolet radiation (UVR) protection against sunburn afforded by a re-application of sunscreen relative to a single application. The study methods were based on the Australian Standard SPF testing regimen, using human volunteers, standardized applications of sunscreen and an artificial solar simulating UVR source. Sunscreen was initially applied, followed by a suberythemal UVR dose; sunscreen was then re-applied, followed immediately by a second period of controlled UV exposure sufficient to induce mild erythema. Compared to the first application, the second sunscreen application afforded 3.1 times more protection against minimal UVR-induced erythema. The combined effect of two sunscreen applications gave on average 2.5 times better protection from UVR than a single sunscreen application. Health authorities worldwide have recommended sunscreen re-application for the prevention of sunburn for some time. This is the first quantitative study to substantiate such recommendations.

Epidemiology of type 1 (insulin-dependent) diabetes mellitus: public health implications in the Middle East

Recent estimates suggest that more than 100,000 inhabitants in the Middle East suffer from type 1 diabetes and that about 6000 subjects in the region develop the disease each year. This paper illustrates how epidemiological principles and methods may assist in a rational assessment of the public health impact of type 1 diabetes in the Middle East. Making a series of assumptions, it is estimated that the future prevalence of type 1 diabetes in the region will increase slightly, but that the increase may be more pronounced if the disease incidence is increasing and the prognosis improved. It is recommended that more valid information is established on the basic epidemiological features of type 1 diabetes in the Middle East, as this will provide the basis of more rational planning of the current and future diabetes healthcare in the region.

Hereditary haemorrhagic telangiectasia: a population-based study of prevalence and mortality in Danish patients

INTRODUCTION

Hereditary haemorrhagic telangiectasia (HHT) is a dominantly inherited disease characterized by telangiectatic lesions. The disease manifestations are variable and include epistaxis, gastrointestinal bleeding, pulmonary arteriovenous malformations and cerebral arteriovenous malformations. Early death due to these complications has been described.

DESIGN

We report a study on the prevalence and mortality of HHT in a Danish population based on two cross-sectional surveys in combination with a long-term follow-up study.

SETTINGS AND SUBJECTS

Prevalent cases of HHT as of 1 January 1974 in the County of Fyn, Denmark, were identified. In 1995-97 a follow-up study of mortality was performed of the initial patient sample, and a new point prevalence rate of HHT as of 1 January 1995 was calculated. All live patients and their families were invited to attend a detailed clinical examination.

RESULTS

The prevalence of HHT in the County of Fyn was 13.8 per 100,000 on 1 January 1974 and 15.6 per 100,000 on 1 January 1995. In the HHT group as a whole, we found a slightly increased mortality; however, amongst the HHT patients younger than 60 years at inclusion the mortality of HHT patients was twice the expected. The excess mortality could be fully explained by severe HHT symptoms.

CONCLUSION

This study suggests that HHT is more prevalent than previously believed. In young patients the disease is associated with an excess mortality which is fully attributable to HHT. Future research should aim at the identification of HHT patients at particular risk of developing severe complications.

Traumatic nerve injuries about the elbow

Although not common, nerve injuries about the elbow occur because of the proximity of the three upper extremity nerves or because of the relationship of the median, ulnar, and radial nerves to the bony and soft-tissue structures about the elbow joint. Nerve injuries at and about the elbow joint occur more frequently with fractures than with any other kind of trauma. Nerve injuries may be found with periarticular fractures, dislocations, gunshot wounds, lacerations, and other iatrogenic causes.

Heterodimerization is required for the formation of a functional GABA(B) receptor

GABA (gamma-aminobutyric acid) is the main inhibitory neurotransmitter in the mammalian central nervous system, where it exerts its effects through ionotropic (GABA(A/C)) receptors to produce fast synaptic inhibition and metabotropic (GABA(B)) receptors to produce slow, prolonged inhibitory signals. The gene encoding a GABA(B) receptor (GABA(B)R1) has been cloned; however, when expressed in mammalian cells this receptor is retained as an immature glycoprotein on intracellular membranes and exhibits low affinity for agonists compared with the endogenous receptor on brain membranes. Here we report the cloning of a complementary DNA encoding a new subtype of the GABAB receptor (GABA(B)R2), which we identified by mining expressed-sequence-tag databases. Yeast two-hybrid screening showed that this new GABA(B)R2-receptor subtype forms heterodimers with GABA(B)R1 through an interaction at their intracellular carboxy-terminal tails. Upon expression with GABA(B)R2 in HEK293T cells, GABA(B)R1 is terminally glycosylated and expressed at the cell surface. Co-expression of the two receptors produces a fully functional GABA(B) receptor at the cell surface; this receptor binds GABA with a high affinity equivalent to that of the endogenous brain receptor. These results indicate that, in vivo, functional brain GABA(B) receptors may be heterodimers composed of GABA(B)R1 and GABA(B)R2.

Buteyko breathing techniques in asthma: a blinded randomised controlled trial

OBJECTIVE

To evaluate the effect of Buteyko breathing techniques (BBT) in the management of asthma.

DESIGN

Prospective, blinded, randomised study comparing the effect of BBT with control classes in 39 subjects with asthma. The study was conducted from January 1995 to April 1995.

PARTICIPANTS AND SETTING

Subjects recruited from the community, aged 12 to 70 years, with asthma and substantial medication use.

MAIN OUTCOME MEASURES

Medication use; morning peak expiratory flow (PEF); forced expiratory volume in one second (FEV1); end-tidal (ET) CO2; resting minute volume (MV); and quality of life (QOL) score, measured at three months.

RESULTS

No change in daily PEF or FEV1 was noted in either group. At three months, the BBT group had a median reduction in daily beta 2-agonist dose of 904 micrograms (range, 29 micrograms to 3129 micrograms), whereas the control group had a median reduction of 57 micrograms (range, -2343 micrograms to 1143 micrograms) (P = 0.002). Daily inhaled steroid dose fell 49% (range, -100% to 150%) for the BBT group and 0 (range, -82% to +100%) for the control group (P = 0.06). A trend towards greater improvement in QOL score was noted for BBT subjects (P = 0.09). Initial MV was high and similar in both groups; by three months, MV was lower in the BBT group than in the control group (P = 0.004). ET CO2 was low in both groups and did not change with treatment.

CONCLUSION

Those practising BBT reduced hyperventilation and their use of beta 2-agonists. A trend toward reduced inhaled steroid use and better quality of life was observed in these patients without objective changes in measures of airway calibre.

Troglitazone inhibits progesterone production in porcine granulosa cells

Troglitazone (a thiazolidinedione that improves insulin resistance) lowers elevated androgen concentrations in women with polycystic ovarian syndrome. In this study, we assessed the direct effects of troglitazone on steroidogenesis in porcine granulosa cells. Troglitazone inhibited progesterone production in a dose- and time-dependent manner (earliest effects at 4 h, maximum at 24 h) without affecting cell viability. Progesterone production was also inhibited by troglitazone in the presence of 25-hydroxycholesterol, indicating that the drug does not affect intracellular cholesterol transport. Troglitazone also inhibited FSH- and forskolin-stimulated progesterone secretion. The reduced progesterone production was accompanied by marked elevations of pregnenolone concentrations, suggesting inhibition of 3beta-hydroxysteroid dehydrogenase (3beta-HSD). The activity of 3beta-HSD in troglitazone-treated granulosa cells was decreased by more than 60%, compared with controls after 24 h. Troglitazone did not affect aromatase activity in porcine granulosa cells. In summary, troglitazone has direct effects on porcine granulosa cell steroidogenesis. The drug specifically inhibits 3beta-HSD activity, resulting in impaired progesterone production. The clinical relevance of this direct in vitro effect on steroidogenesis needs further investigation.

The origin of red blood cell biopterin

Data are presented to support the hypothesis that the biopterin content of red blood cells arises during erythropoiesis. Only when the plasma concentration rises above the erythrocyte concentration of biopterin is there likely to be diffusion into the cell.

Functional characterization and exon 2-intron 2-exon 3 gene sequence of HLA-B*2712 as found in a British family

The HLA-B*27 group of alleles has been extensively studied due to the association of particular B*27 alleles with ankylosing spondylitis (AS). We describe here an HLA-B*27 allele (B*2712) encoding an antigen that lacks reactivity with B27 monoclonal antibodies (moabs) and alloantisera but reacts with some B40/B60 moabs and alloantisera and expresses the Bw6 public epitope. This allele was discovered by the segregation of an HLA-B allele undetectable by PCR-SSP within a Caucasian family from the British population referred for routine bone marrow transplant HLA typing and found in the haplotype A*29; B*2712; Cw*1203; DRB1*13; DQB1*0603. Serological typing showed a lack of reactivity with four B27 moabs and four alloantisera but positive reactivity with moabs and alloantisera specific for B40/B60 and Bw6 public epitopes. Subsequent sequencing showed the closest homology was with B*2708 with three mismatches in exon 2 at positions 204, 209 and 210. The intron 2 sequence was identical with other B*27 lineage alleles including a 2 base pair deletion at positions 95 and 96. The relationship between HLA-B*2712 and reported B60 associations with susceptibility to AS remains to be determined.

Milk consumption, galactose metabolism and ovarian cancer (Australia)

OBJECTIVES

It has been suggested that increased exposure to galactose, due to high consumption of dairy foods or reduced galactose metabolism, is associated with the development of ovarian cancer. We have investigated this in a large case-control study conducted in three Australian states between 1990 and 1993.

METHODS

Approximately 800 histologically-confirmed cases, 800 community controls and 300 controls recruited through breast-screening clinics completed dietary questionnaires. Approximately 100 cases and all breast-screening controls also provided a blood sample for analysis of galactose-1-phosphate-uridyltransferase (GALT).

RESULTS

Ovarian cancer risk was positively associated with increasing consumption of whole milk and other full-fat dairy foods, but was not associated with consumption of low-fat dairy foods and was inversely related to consumption of skimmed milk. There was no association between ovarian cancer and GALT except among women with abnormally low GALT who had a non-significant 2.5-fold increased risk of ovarian cancer.

CONCLUSIONS

These data do not support the hypothesis that galactose plays a major role in the development of ovarian cancer and suggest that reported associations between milk consumption and ovarian cancer are due to the fat content of milk and not to lactose or galactose. An increased risk of ovarian cancer in women with abnormally low levels of GALT cannot, however, be ruled out.

Relationship between number of ovulatory cycles and accumulation of mutant p53 in epithelial ovarian cancer

BACKGROUND

It has been suggested that increased numbers of ovulations might increase the risk of p53 gene (also known as TP53) mutation in the ovarian epithelium, thereby leading to the development of cancer. The data supporting this hypothesis have come from an observation that accumulation of p53 protein in epithelial ovarian cancer was strongly associated with increasing numbers of ovulatory cycles. We have further investigated the association between ovulatory history and p53 gene mutation by use of data from a large case-control study of ovarian cancer in Australia.

METHODS

Tissue blocks were available for immunohistochemical analysis of p53 protein from 234 case subjects, aged 18-79 years, who had invasive epithelial ovarian cancer. Epidemiologic data were also available for these women and for 855 control subjects. Case-case comparisons were made by use of prevalence ratios and 95% confidence intervals (CIs), and case-control comparisons were made by use of odds ratios (ORs) and 95% CIs. All statistical tests were two-sided.

RESULTS

There was no association between p53 accumulation and years of ovulation. Women with p53-positive cancers had undergone an average of 29.3 years of ovulation compared with 29.0 years of ovulation for women with p53-negative cancers (P=.8). Although the overall risk of ovarian cancer development was significantly increased in women who had undergone more years of ovulation (OR=2.17; 95% CI =1.54-3.05-for > or =35 years versus <23 years of ovulation), there was no difference in the risk associated with p53-positive and p53-negative cancers.

CONCLUSIONS

These results confirm the association between increased ovulation and ovarian cancer risk but do not support the hypothesis that this association is due to an increased risk of p53 mutation with a greater number of ovulatory cycles.

Action STAT! The crisis nurse

To provide quality care with limited staff and create a safer environment, managers created a new "crisis nurse" position.

Population screening for neonatal liver disease: a feasibility study

BACKGROUND

Extra-hepatic biliary atresia and several other causes of neonatal liver disease carry high mortality and morbidity rates, especially if not treated early in life. Despite professional recommendations, delayed referral of infants with prolonged jaundice continues to be a significant problem. One approach to reducing the age of referral and diagnosis is population screening to detect significant conjugated hyperbilirubinaemia as an index of liver dysfunction.

METHODS

To investigate this possibility, and to provide reference data on bilirubin and its conjugated and unconjugated fractions in a normal newborn population, 1157 neonates were anonymously tested (median age 7 days, range 4-28 days) using surplus plasma from routinely collected neonatal screening specimens, using dry slide chemistry.

RESULTS

Of 2310 specimens received, 50% were suitable for analysis. The remainder were either haemolysed or insufficient (10% and 40% of the total, respectively). Total bilirubin concentrations ranged from 9 to 428 micromol/l and conjugated bilirubin from 0 to 175 micromol/l, although the latter was rarely increased to more than 30 micromol/l (2.5th-97.5th percentile ranges 15-285 micromol/l and 0-18 micromol/l, respectively). The range of the percentage of conjugated bilirubin was 0-57% (2.5th-97.5th percentile; range 0-20%).

CONCLUSION

An increased conjugated bilirubin, expressed as a concentration or as the percentage of the total bilirubin, could be used as a specific marker to screen for liver dysfunction in neonates. This approach has the potential to improve the age of referral and the prognosis of infants with neonatal liver disease.

The primordial mind and the work of the negative

This paper was given at the celebration of Bion's centennial in 1997. At the request of the organisers of this conference, the work of Bion has been brought into perspective with the author's. The author has chosen to illumine Bion's concept of the primordial mind and considers the transformation of the beta-elements into the alpha ones. He also refers to Bion's distinction of thoughts without thinker and thinking as needing thoughts to be thought by a thinker (thinking apparatus). The main point of the paper is Bion's opposition of 'nothing' and 'no thing'. The author refers to Freud's paper on 'Negation'. He recalls his own model of the double limit. He tries to show how Freud's conception of representation has a much wider field than is usually stated. He emphasises differences between Freud's and Bion's 'basic assumptions'. After having tried to clarify Bion's ideas on 'O', 'K and -K', he recalls Bion's reference to Keats's negative capability. The author then gives a short account of his own concept of the 'work of the negative', finding correspondences with Bion's own concepts. As a conclusion two Indian myths are recalled for their great symbolic value.

Alteration of zif268 zinc-finger motifs gives rise to non-native zinc-co-ordination sites but preserves wild-type DNA recognition

Zinc fingers are among the major structural motifs found in proteins that are involved in eukaryotic gene regulation. Many of these zinc-finger domains are involved in DNA binding. This study investigated whether the zinc-co-ordinating (Cys)2(His)2 motif found in the three zinc fingers of zif268 could be replaced by a (Cys)4 motif while still preserving DNA recognition. (Cys)2(His)2-to-(Cys)4 mutations were generated in each of the three zinc fingers of zif268 individually, as well as in fingers 1 and 3, and fingers 2 and 3 together. Whereas finger 1 and finger 3 tolerate the switch, such an alteration in finger 2 renders the polypeptide incapable of DNA recognition. The protein-DNA interaction was examined in greater detail by using a methylation-interference assay. The mutant polypeptides containing the (Cys)4 motif in fingers 1 or 3 recognize DNA in a manner identical to the wild-type protein, suggesting that the (Cys)4 motif appears to give rise to a properly folded finger. Additional results indicate that a zif268 variant containing a (Cys)2(His)(Ala) arrangement in finger 1 is also capable of DNA recognition in a manner identical to the wild-type polypeptide. This appears to be the first time that such alterations, in the context of an intact DNA-binding domain, have still allowed for specific DNA recognition. Taken together, the work presented here enhances our understanding of the relationship between metal ligation and DNA-binding by zinc fingers.

Characterization of the glnK-amtB operon of Azotobacter vinelandii

To determine whether in Azotobacter vinelandii the PII protein influences the regulation of nif gene expression in response to fluxes in the ammonium supply, the gene encoding PII was isolated and characterized. Its deduced translation product was highly similar to PII proteins from other organisms, with the greatest degree of relatedness being exhibited to the Escherichia coli glnK gene product. A gene designated amtB was found downstream of and was contranscribed with glnK as in E. coli. The AmtB protein is similar to functionally characterized ammonium transport proteins from a few other eukaryotes and one other prokaryote. glnK and amtB comprise an operon. Attempts to isolate a stable glnK mutant strain were unsuccessful, suggesting that glnK, like glnA, is an essential gene in A. vinelandii. amtB mutants were isolated, and although growth on limiting amounts of ammonium was similar in the mutant and wild-type strains, the mutants were unable to transport [14C]methylammonium.

Serum inhibins A and B fall differentially as FSH rises in perimenopausal women

BACKGROUND

Serum FSH levels rise with increasing age in normal women, particularly as they enter the menopausal transition and progress to the postmenopausal state. The contributions of decreasing levels of inhibin-A (INH-A) and inhibin-B (INH-B) to this rise are presently unclear, as there are no reports of dimeric INH levels in relation to menopausal status. The present study was undertaken in order to provide preliminary data on relationships amongst the dimeric inhibins, oestradiol (E2) and FSH in normal subjects of defined menopausal status.

METHODS

Single serum samples were obtained between cycle days 3 and 8 in regularly cycling women, or at random in those with irregular cycles or amenorrhoea, in 110 women, aged 48-59 years, in the third year of a prospective longitudinal study of the menopausal transition, 'The Melbourne Women's Mid-Life Health Project'. Samples were assayed for FSH, E2, INH-A, INH-B and immunoreactive inhibin (IR-INH) and results were analysed following logarithmic transformation. Undetectable values were assigned the limit of sensitivity of the respective assays. The relationships between hormones were evaluated as a function of menopausal stage. The latter was assigned as Stage 1, premenopausal (no reported change in menstrual cycle pattern), Stage 2, early peri-menopausal (reported change in menstrual cycle frequency in the preceding year with a bleed in the preceding 3 months), Stage 3, late peri-menopausal (no menses in the preceding 3-11 months) and Stage 4, postmenopausal (no menses in the preceding 12 months).

RESULTS

The hormone concentrations in premenopausal subjects (geometric means, FSH 13.5 IU/l, E2 306 pmol/l, IR-INH 217 U/l, INH-A 96 ng/l, and INH-B 48 ng/l) were used as reference points for the other stages of menopausal status. Early peri-menopausal subjects had significantly lower levels of IR-INH (147 U/l) and INH-B (13.5 ng/l) in the presence of a small, statistically nonsignificant rise in FSH (to 21.4 U/l) and no significant change in E2 or INH-A. In late peri-menopausal subjects, IR-INH fell to 76 U/l, INH-A fell to 4.2 ng/l, whilst INH-B was not significantly different at 14 ng/l. FSH had risen significantly to 72.21 U/l. Oestradiol also fell significantly to 89 pmol/l. In the postmenopausal subjects there were no further significant changes in the peptide hormones or FSH, but E2 fell further to 41 pmol/l. There was a significant (P < 0.05) inverse correlation between FSH and E2 (R = -0.78), FSH and IR-INH (R = -0.66), FSH and INH-A (R = -0.53), FSH and INH-B (R = -0.29) while IR-INH and either INH-A or INH-B were positively correlated (R = +0.57 and +0.35, respectively). The data are consistent with negative feedback roles for both dimeric inhibins and E2 as contributors to the regulation of FSH secretion as menopausal status changes.

CONCLUSIONS

The major significant endocrine event in women in the early peri-menopausal phase of the menopausal transition is a substantial fall in the circulating levels of inhibin-B with no significant change in inhibin-A or oestradiol. Progression to late peri-menopausal status is accompanied by a marked fall in inhibin-A and oestradiol and a rise in FSH without further change in inhibin-B. Inhibin-B, a marker of follicle number, is a significant factor in the endocrinology of the menopausal transition.