Anthony P. Payne

Altered sirtuin expression is associated with node-positive breast cancer

Sirtuins are genes implicated in cellular and organismal ageing. Consequently, they are speculated to be involved in diseases of ageing including cancer. Various cancers with widely differing prognosis have been shown to have differing and characteristic expression of these genes; however, the relationship between sirtuin expression and cancer progression is unclear. In order to correlate cancer progression and sirtuin expression, we have assessed sirtuin expression as a function of primary cell ageing and compared sirtuin expression in normal, ‘nonmalignant’ breast biopsies to breast cancer biopsies using real-time polymerase chain reaction (PCR). Levels of SIRT7 expression were significantly increased in breast cancer (P<0.0001). Increased levels of SIRT3 and SIRT7 transcription were also associated with node-positive breast cancer (P<0.05 and P<0.0001, respectively). This study has demonstrated differential sirtuin expression between nonmalignant and malignant breast tissue, with consequent diagnostic and therapeutic implications.

The effects of pre‐ and postnatal exposure to the nonsteroidal antiandrogen flutamide on testis descent and morphology in the Albino Swiss rat

Exposure of male Albino Swiss rats to the nonsteroidal antiandrogen flutamide during the period from gestational day (d) 10 to birth resulted in feminisation of the external genitalia and the suppression of growth of the male reproductive tract. In adulthood, testes were found to be located in diverse positions. True cryptorchidism occurred in 10% of cases, whereas 50% of testes descended to the scrotum and 40% were located in a suprainguinal ectopic region. Varying degrees of tubule abnormality were seen in the testes of flutamide‐treated animals, ranging from completely normal tubules with full spermatogenesis (and the expected frequency of the stages of spermatogenesis) to severely abnormal tubules lined with Sertoli cells only. For each individual testis, the overall severity of tubule damage was strongly correlated with its adult location, with intra‐abdominal testes worst affected and scrotally‐located testes least; only the latter contained normal tubules. Similarly, intra‐abdominal testes were the smallest in weight and contained the least testosterone. By contrast, postnatal treatment of male rats with flutamide from birth to postnatal d 14 did not impair development of the external genitalia, the process of testicular descent or adult spermatogenesis. These findings confirm that androgen blockade during embryonic development interferes with testicular descent but also demonstrate that (1) prenatal flutamide treatment per se has a detrimental effect on adult testis morphology but (2) the degree of abnormality of the testes is strongly influenced by location.

The effect of neonatal manipulation of hypothalamic serotonin levels on sexual activity in the adult rat

5HT and 5HIAA levels were altered in neonatal males and females by treating them with 100 mg/kg p-chlorophenylalanine (PCPA) or 20 mg/kg 5-hydroxytryptophan (5HTP) over eight days 1 to 7 or 11 to 16 of life. Androgenized females (testosterone propionate given on day 1) were also treated over days 1 to 7. In adulthood the effects of these treatments on sexual behaviour were observed. None of the treatments affected feminine sexual behaviour in either sex. Reduction of 5HT activity by PCPA enhanced masculine sexual behaviour in males and potentiated the defeminizing effect of exogenous testosterone in females. Increasing 5HT by 5HTP antagonised the defeminizing effect of exogenous testosterone. These findings indicate that the lower levels of hypothalamic 5HT and 5HIAA seen in the neonatal males may have some physiological importance, since 5HT appears to antagonise the androgenizing and defeminizing effects of testosterone.

Sex differences in haem biosynthesis and porphyrin content in the harderian gland of the golden hamster

Methods are described for the measurement of seven haem biosynthetic enzymes in Harderian gland tissue from male and female golden hamsters. Sex differences were found in five of the seven enzymes. In each case, female tissue exhibited higher activity than male tissue. These differences in enzyme activity are sufficient to account for the major sex difference in porphyrin content in the Harderian gland of this species.

Comparative Analysis of the Structural Properties of the Collateral Ligaments of the Human Knee

STUDY DESIGN Controlled laboratory study. BACKGROUND Varus knee instability arising from lateral collateral ligament (LCL) injury increases stress on cruciate ligament grafts, potentially leading to failure of reconstructed ligaments. In contrast to the medial collateral ligament (MCL), little is known about the structural properties of the LCL. OBJECTIVES To compare the tensile properties of the LCL and MCL complex of the human knee joint. METHODS Ten fresh-frozen cadaveric knees (mean ± SD age, 81 ± 11 years), free of gross musculoskeletal pathology, were obtained. Following dissection, the length, width, and thickness of the ligaments were measured using calipers, and bone-ligament-bone preparations were mounted in a uniaxial load frame. After preconditioning, specimens were extended to failure at a rate of 500 mm/min (approximately 20%/s). Force and crosshead displacement were used to calculate structural properties, including stiffness, yield strength, ultimate tensile strength, and failure energy. RESULTS The fan-shaped MCL was significantly longer (60%; P<.001), wider (680%; P<.001), and thinner (19%; P = .009) than the cord-like LCL. The LCL failed at either the fibular attachment (n = 6) or midsubstance (n = 4), while failure of the MCL primarily occurred at the femoral attachment (n = 7). Although the ultimate tensile strength of the MCL (mean ± SD, 799 ± 209 N) was twice that of the LCL (392 ± 104 N; P<.001), there was no significant difference in stiffness of the ligaments (MCL, 63 ± 14 N/mm; LCL, 59 ± 12 N/mm). CONCLUSIONS Despite differences in geometry and strength, there was no significant difference in stiffness of the MCL and LCL when tested in vitro.

A candidate gene for human neurodegenerative disorders: a rat PKCγ mutation causes a Parkinsonian syndrome

Rats harboring the agu mutation have altered behavior and brain pathology resembling human Parkinsonian syndromes; notably, they have a movement disorder and age-progressive dysfunction and death of neurons in the midbrain (substantia nigra pars compacta) that use dopamine as a neurotransmitter. We present evidence that this phenotype is due to a mutation in the rat protein kinase Cγ (in rat, Prkcg; in mouse, Prkcc; in human, PRKCG) gene, which generates a premature stop codon, drastically reducing the level of synthesis of the catalytic domain of the brain-specific protein kinase Cγ protein.

Topographic anatomy of the nerve to masseter: An anatomical and clinical study

BACKGROUND The use of the motor nerve to masseter has proved to be a reliable and sensible solution in facial reanimation as a donor for free muscle transfer. In this paper we describe the topographic anatomy of the nerve to masseter and our original technique for its quick and safe harvesting. METHODS This anatomical study is based on the dissection of the nerve to masseter in 17 embalmed cadaverous sites and is focused on the anatomical relations between the nerve and the surrounding structures. Also buccal and zygomatic branches of the facial nerve were dissected and assessed and the resulting data are compared. RESULTS The nerve to masseter has a predictable track inside the muscle which can be identified topographically within a square area under the zygomatic arch. This area is different between males and females and its accuracy has been tested on six patients at the Canniesburn Unit. CONCLUSIONS The nerve to masseter emerges in a very predictable point from the mandibular notch - immediately below the zygomatic arch - to run within the muscle belly. The approach here described allows safer and faster harvesting of the nerve to masseter with minimal dissection through the muscle.

SIRT2: Tumour suppressor or tumour promoter in operable breast cancer?

PURPOSE Sirtuins comprise a family of genes involved in cellular stress, survival and damage responses. They have been implicated in a range of diseases including cancer, with most information pertaining to their function in tumourigenesis being derived from in vitro studies, or model organisms. Their putative roles as tumour suppressors or tumour promoters remain to be validated in vivo. Little is known about their role in breast tumourigenesis. We sought to evaluate the seven sirtuin family members (SIRT1-7) in a human breast cancer cohort, in relation to clinico-pathological features and outcome of the disease. MATERIALS AND METHODS Immunohistochemical analysis of SIRT1-7 protein levels was undertaken in 392 oestrogen receptor (ER+ve) and 153 ER-ve breast tumour samples. SIRT1-7 transcriptional levels were assessed in normal (n=25), non-malignant (n=73) and malignant (n=70) breast tissue using Relative Quantitative Real Time PCR. Statistical analyses determined if SIRT1-7 transcription or protein expression was associated with clinical parameters or outcome. RESULTS In ER-ve tumours, high protein levels of nuclear SIRT2 were associated with reduced time to recurrence and disease-specific death. This association was only observed in Grade 3 tumours. In the ER+ve cohort, high SIRT2 nuclear levels were associated with shorter disease-free survival and time to recurrence whilst on Tamoxifen, in patients with Grade 3 tumours. Conversely, in Grade 2 tumours, high SIRT2 levels were associated with increased time to recurrence. CONCLUSIONS Our data suggest that SIRT2 is the sirtuin predominantly involved in breast tumourigenesis and prognosis. It indicates that SIRT2 acts as a tumour suppressor or tumour promoter dependent upon breast tumour grade.

The AS/AGU rat: a spontaneous model of disruption and degeneration in the nigrostriatal dopaminergic system

The AS/AGU rat provides an alternative to experimentally produced laboratory models of basal ganglia disorders. This mutant is characterised by disturbances of movement including clumsy gait, whole body tremor, rigidity and difficulty in initiating movement. From an early age, there is a profound depletion of extracellular dopamine in the dorsal caudate‐putamen as measured via in vivo microdialysis; levels are only 10–20% of those found in the parent Albino Swiss (AS) strain. Subsequently a depletion of whole tissue dopamine levels occurs and, later still, loss of dopaminergic cells in the substantia nigra pars compacta. The dysfunction in movement and the nigrostriatal dopaminergic system are clearly linked, since movement can be ameliorated by L‐DOPA administration. Furthermore, there are depletions in glucose utilisation in several regions of the basal ganglia circuitry, including the substantia nigra pars compacta, the subthalamic nucleus and the ventrolateral thalamus. The AS/AGU rat represents a unique opportunity to investigate the intrinsic factors controlling the integrity of dopaminergic systems and the recent successful positional cloning of the agu gene will allow the molecular mechanisms underlying this interesting phenotype to be analysed.

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC ANALYSES OF PORPHYRINS IN HAMSTER HARDERIAN GLANDS

Porphyrin content and 5-aminolaevulinate synthase activity of the Harderian gland were measured in intact and gonadectomized male and female hamsters; porphyrin profiles were analysed by high-pressure liquid chromatography. The total porphyrin content of the two female groups was similar, but enzyme activity in females ovariectomised for 20 weeks significantly decreased. Intact males have low porphyrin content and enzyme activity, while in castrates (6 weeks) both increased to female levels. Protoporphyrin IX formed 93% of total porphyrins in intact females, compared with 70% of total porphyrins in intact males. The remainder in both sexes was chiefly penta- and hexacarboxylic porphyrins and coproporphyrin and (in females) Harderoporphyrin. Gonadectomy in either sex resulted in protoporphyrin levels intermediate between male and female values.