The influence of the Pro12Ala mutation of the PPAR-gamma receptor gene on metabolic and clinical characteristics in treatment-naïve patients with type 2 diabetes

Peroxisome proliferator activated receptor-gamma is an important factor in adipocyte differentiation and energy metabolism and is thus a candidate gene for obesity, insulin resistance and dyslipidaemia. We therefore assessed the associations between the most common variant of the PPAR-gamma, the Pro12Ala (P12A) substitution in the PPAR-gamma 2 gene, with BMI, blood pressure, fasting plasma glucose, HbA1c, total cholesterol, LDL and HDL cholesterol and plasma triglyceride in 183 treatment-naïve patients with type 2 diabetes (T2D). The P12A allele associated with lower fasting plasma glucose but had no influence on HbA1c or BMI. In obese patients (BMI > 29 kg/m2), the P12A substitution associated with elevated total and non-HDL cholesterol levels.

B cell non-Hodgkin cerebral lymphoma associated with an anaplastic oligodendroglioma

Primary central nervous system lymphomas and anaplastic oligodendrogliomas are not uncommon; however, no association between the 2 has been documented to date. We describe a unique case, whereby a patient presenting with seizures and slight impairment of higher functions, underwent frontal lobectomy for a mass lesion. The histology revealed dual pathology of anaplastic oligodendroglioma and B cell non-Hodgkin lymphoma. Postoperatively, the patient received whole brain radiotherapy. The patient remained well after 18 months of follow-up with no radiological progression of a known tumor residuum.

Multimodality image-guided epilepsy surgery

Co-registration of imaging modalities in the diagnosis of epilepsy is now commonly used in major epilepsy centres. However, the incorporation of these registrations into an image-guided system has only recently been developed. Using techniques of segmentation, surface matching and/or voxel-based matching, we have been able to co-register FLAIR MRI, SPECT, PET, and subdural grids into the 3-D space of the volumetric MRI and use these images on the StealthStation Image-Guided System to resect these foci. This greatly aids the surgeon in performing a more precise tailoring of the cortical resection so as to maximize the excision of the epileptogenic zone while minimizing the impact on eloquent cortex and epileptogenic foci.

Integrative noetic therapies as adjuncts to percutaneous intervention during unstable coronary syndromes: Monitoring and Actualization of Noetic Training (MANTRA) feasibility pilot

BACKGROUND

Patients undergoing percutaneous coronary intervention (PCI) for unstable coronary syndromes have substantial emotional and spiritual distress that may promote procedural complications. Noetic (nonpharmacologic) therapies may reduce anxiety, pain and distress, enhance the efficacy of pharmacologic agents, or affect short- and long-term procedural outcomes.

METHODS

The Monitoring and Actualization of Noetic Training (MANTRA) pilot study examined the feasibility of applying 4 noetic therapies-stress relaxation, imagery, touch therapy, and prayer-to patients in the setting of acute coronary interventions. Eligible patients had acute coronary syndromes and invasive angiography or PCI. Patients were randomized across 5 treatment groups: the 4 noetic and standard therapies. Questionnaires completed before PCI reflected patients' religious beliefs and anxiety. Index hospitalization end points included post-PCI ischemia, death, myocardial infarction, heart failure, and urgent revascularization. Mortality was followed up for 6 months after hospitalization.

RESULTS

Of eligible patients, 88% gave informed consent. Of 150 patients enrolled, 120 were assigned to noetic therapy; 118 (98%) completed their therapeutic assignments. All clinical end points were available for 100% of patients. Results were not statistically significant for any outcomes comparisons. There was a 25% to 30% absolute reduction in adverse periprocedural outcomes in patients treated with any noetic therapy compared with standard therapy. The lowest absolute complication rates were observed in patients assigned to off-site prayer. All mortality by 6-month follow-up was in the noetic therapies group. In patients with questionnaire scores indicating a high level of spiritual belief, a high level of personal spiritual activity, a low level of community-based religious involvement, or a high level of anxiety, noetic therapies appeared to show greater reduction in absolute in-hospital complication rates compared with standard therapy.

CONCLUSIONS

Acceptance of noetic adjuncts to invasive therapy for acute coronary syndromes was excellent, and logistics were feasible. No outcomes differences were significant; however, index hospitalization data consistently suggested a therapeutic benefit with noetic therapy. Of all noetic therapies, off-site intercessory prayer had the lowest short- and long-term absolute complication rates. Definitive demonstration of treatment effects of this magnitude would be feasible in a patient population about 4 times that of this pilot study. Absolute mortality differences make safety considerations a mandatory feature of future clinical trials in this area.

Familial deletion of (8)(q24.13q24.22) associated with a normal phenotype

We report a familial deletion of (8q) detected in amniocytes of a fetus with a normal ultrasound and in the phenotypically normal mother, who has now had three pregnancy losses. Chromosome analysis of amniocytes and maternal peripheral blood cells showed an interstitial deletion of (8)(q24.13q24.22), which is distal to the region associated with Langer-Giedion syndrome (LGS) or trichorhinophalangeal (TRP) syndrome. This deletion was confirmed by fluorescence in situ hybridization with a c-myc cosmid clone and chromosome 8 painting library.

Modeling of powder blending using on-line near-infrared measurements

A model to quantify the degree of mixing in pharmaceutical powder mixing operations was developed. The additive volume mixing model is based on the determination of the characteristic volume of agitation for a given blender, which is dependent on process parameters such as the formulation ingredients, the geometry of the mixer, and the batch load. The calculation of this characteristic volume of agitation is based on the determination of the fitted fraction of formulation mixed after the first blender rotation. A variation of this model, denominated the iterative mixing model, was also developed. On-line near-infrared (NIR) measurements were taken throughout the runs to obtain the mixing profile and the dynamics of the powder bed as a function of blender rotations. Studies were conducted at two scales using two different formulations to study and compare the calculated characteristic volume of agitation for each blender-formulation system. This approach elucidates the existing relationship between the characteristic mixing parameters and critical rotations (required rotations to achieve content uniformity) for a given system and represents a step toward scale-up of solids mixing operations.

Ultraviolet-B exposure leads to up-regulation of senescence-associated genes in Arabidopsis thaliana

Exposure to UV-B radiation resulted in a loss of chlorophyll and an increase in lipid damage in a similar manner to that induced during natural senescence. In addition, exposure to UV-B led to the induction of a number of genes associated with senescence (SAG12, 13, 14, and 17). These results show, for the first time, that exposure to UV-B can lead to cellular decline through active and regulated processes involving many genes also associated with natural senescence.

Three-year survey of bacteremia and fungemia in a pediatric intensive care unit

BACKGROUND

Knowledge of the pattern of blood stream infection (BSI) in patients in intensive care units (ICUs) can help determine antibiotic prescribing policy and infection control procedures. However, there have been few pediatric-based studies.

METHODS

Surveillance of BSI in a pediatric ICU for 3 years, amounting to 131 episodes of significant bacteremia and fungemia.

RESULTS

The incidence of BSI was 39.0 per 1,000 admissions (10.6 per 1,000 bed days). Eighty-four (64.1%) episodes were ICU-acquired, and 27 (20.6%) were community-acquired. Gram-positive, Gram-negative and anaerobic bacteria accounted for 62.2, 30.8 and 1.4%, respectively, of the 143 microorganisms isolated, 5.6% were yeasts. Neisseria meningitidis was the most common species in community-acquired infections, and staphylococci predominated in hospital-acquired episodes. Eighty-seven percent of patients had significant underlying disease, including 60.3% with congenitally acquired conditions. Intravascular devices were the most common source of infection, accounting for 41.2% of all episodes. The crude mortality in children with BSI was 26.5%, compared with 8.1% in those without BSI.

CONCLUSIONS

The pattern of BSI in ICUs is partly determined by the type of patient treated. However, some observations are generally applicable, notably the increasing importance of antibiotic-resistant bacteria that are often of low virulence and device-associated. Our experience suggests that universal use of broad spectrum empiric antibiotics to cover these pathogens (which risks further promoting antibiotic resistance) may not improve patient outcome. Our study provides a basis for other pediatric ICUs to evaluate their rates and outcomes of BSI.

Growing pains of East Timor: health of an infant nation

In August, 1999, three-quarters of East Timorese adults voted to end more than two decades of an Indonesian administration never recognised by the United Nations. The ensuing spree of violence and destruction by militia backed by the Indonesian military meant the birth of the fledgling nation became a complex humanitarian disaster. 1 year on, progress was heartening: a transitional government, a judiciary, and tax systems were in place, and East Timor was a proud competitor in the Sydney Olympic games. Rebuilding a country from ground level has brought a golden opportunity for fresh approaches. However, reconstruction is also a slow, complex, and sometimes controversial process at the mercy of multiple agendas. The health sector has seen basic care restored, establishment of a much-needed public-health service, and planning for the future health system. An innovative partnership between WHO/Roll Back Malaria and Merlin for post-conflict research has provided data to guide malaria control. The story of progress from humanitarian emergency to national health plan epitomises the triumphs and challenges of this newest nations' first 18 months.

Modulation of MK-801-induced behaviour by noradrenergic agents in mice

RATIONALE

Inhibition of glutamatergic N-methyl-D-aspartate (NMDA) receptors following the administration of NMDA receptor antagonists results in psychotic-like behaviour. Whereas it is known that pharmacological manipulation of dopaminergic and serotonergic pathways affect this drug-induced psychosis, a role for noradrenaline has not yet been clearly defined.

OBJECTIVES

Thus, in the present study, we assessed a possible role for noradrenaline in the behavioural response to the non-competitive NMDA receptor anatgonist, MK-801, in male CD-I mice.

RESULTS

MK-801 (0.02-1.28 mg/kg; ED50 0.2 mg/kg; s.c.) induced a dose-dependent increase in locomotor, stereotypic and ataxic behaviours. Pre-treatment with the noradrenaline re-uptake inhibitors, desipramine (10 mg/kg; i.p.) and reboxetine (20 mg/kg; i.p.), attenuated the locomotor, stereotypic and ataxic response to MK-801 (0.2 mg/kg; s.c.). The noradrenergic system was lesioned with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4, 50 mg/kg; i.p., 7 and 4 days prior to challenge) to reduce noradrenaline concentrations in the cortex by 70%-80%. Whereas DSP-4 lesioning had little effect on the response to MK-801, it completely reversed the attenuating effects of reboxetine. Pre-treatment with the alpha2 adrenoceptor agonist, clonidine (0.2 mg/kg; i.p.), and the antagonist, yohimbine (2 mg/kg; i.p.), attenuated and potentiated the response to MK-801, respectively. Pre-treatment with the alpha1 adrenoceptor antagonist, prazosin (2 mg/kg; i.p.), reduced the MK-801-induced response.

CONCLUSIONS

It therefore appears that presynaptic noradrenergic alpha2 and postsynaptic alpha1 adrenoceptor stimulation exert opposing effects on the behavioural expression of MK-801 in mice.

The relationships between post-prandial lipaemia, endothelial function and oxidative stress in healthy individuals and patients with type 2 diabetes

Post-prandial lipaemia (PPL) is a factor in atherogenesis and results in reversible endothelial dysfunction in healthy individuals. Oxidative stress and triglyceride (TG)-rich lipoproteins have been implicated. Type 2 diabetes (NIDDM) results in exaggerated PPL. We attempted to delineate the mechanisms of PPL induced, endothelial dysfunction (EF) and oxidative stress in 12 NIDDM and 12 matched healthy subjects. Subjects underwent a fat tolerance test, with endothelial function assessed by flow-mediated vasodilatation and oxidative stress measured by venous lipid-derived free radicals ex vivo and lipid peroxidation products over the postprandial phase. Fasting TG, post-prandial hypertriglyceridaemia and the TG enrichment of all lipoproteins was significantly greater in NIDDM. Post-prandial endothelial function inversely correlated with fasting HDL-C (r=-0.84, P=0.001) in both the control and NIDDM groups. The deterioration in EF in the NIDDM group also correlated with TG enrichment of VLDL and LDL. PPL in both groups also resulted in increased oxidative stress. The increment in free radicals correlated with TG enrichment of VLDL in both groups and was, therefore, greater in NIDDM. Thus, PPL -- with the production of TG-enrichment of VLDL -- results in endothelial dysfunction by an oxidative stress mechanism in both groups. The magnitude is greater in NIDDM. Fasting HDL-C appears to contribute to the protection of the endothelium against this phenomenon. Hence, exaggerated PPL associated with reduced HDL-C may be important in the pathogenesis of vascular disease, particularly in NIDDM.

Functional genomic studies of aldo-keto reductases

Aldose reductase (AR) is considered a potential mediator of diabetic complications and is a drug target for inhibitors of diabetic retinopathy and neuropathy in clinical trials. However, the physiological role of this enzyme still has not been established. Since effective inhibition of diabetic complications will require early intervention, it is important to delineate whether AR fulfills a physiological role that cannot be compensated by an alternate aldo-keto reductase. Functional genomics provides a variety of powerful new tools to probe the physiological roles of individual genes, especially those comprising gene families. Several eucaryotic genomes have been sequenced and annotated, including yeast, nematode and fly. To probe the function of AR, we have chosen to utilize the budding yeast Saccharomyces cerevisiae as a potential model system. Unlike Caenorhabditis elegans and D. melanogaster, yeast provides a more desirable system for our studies because its genome is manipulated more readily and is able to sustain multiple gene deletions in the presence of either drug or auxotrophic selectable markers. Using BLAST searches against the human AR gene sequence, we identified six genes in the complete S. cerevisiae genome with strong homology to AR. In all cases, amino acids thought to play important catalytic roles in human AR are conserved in the yeast AR-like genes. All six yeast AR-like open reading frames (ORFs) have been cloned into plasmid expression vectors. Substrate and AR inhibitor specificities have been surveyed on four of the enzyme forms to identify, which are the most functionally similar to human AR. Our data reveal that two of the enzymes (YDR368Wp and YHR104Wp) are notable for their similarity to human AR in terms of activity with aldoses and substituted aromatic aldehydes. Ongoing studies are aimed at characterizing the phenotypes of yeast strains containing single and multiple knockouts of the AR-like genes.

Plutonium solubility in sediment pore waters

Using in situ porous cup samplers, dissolved Pu concentrations have been measured over a year in the pore waters from two contrasting sites in the valley of the River Esk, North West England. In saltmarsh sediments, dissolved Pu represents approximately 1 part in 10(6) of the total inventory. The Pu concentration in solution is in the range 1.1-3.5 mBq l-1, varying by a factor of 3 in the course of the year. Most of the changes in dissolved Pu coincide with changes in dissolved Fe and Mn concentrations, with Pu being low in the summer months when Fe and Mn are high. Nevertheless, there are a number of factors which make it unclear as to whether these patterns might be related to seasonal redox changes in the saltmarsh. At the highly organic, reducing reedbed site, the proportion of Pu in solution is typically around 1 part in 10(3), proportionately much higher than in the saltmarsh, giving concentrations ranging between 9.0 and 28.5 mBq l-1, and are apparently maintained by complexation to dissolved organic matter. There is no obvious seasonal pattern at the reedbed site nor is there any relation to any of the dissolved species measured (Fe, Mn, Na, DOC).

Neuronal nitric oxide synthase and systemic vasodilation in rats with cirrhosis

Cirrhosis is typically associated with a hyperdynamic circulation consisting of low blood pressure, low systemic vascular resistance (SVR), and high cardiac output. We have recently reported that nonspecific inhibition of nitric oxide synthase (NOS) with nitro-L-arginine methyl ester reverses the hyperdynamic circulation in rats with advanced liver cirrhosis induced by carbon tetrachloride (CCl(4)). Although an important role for endothelial NOS (eNOS) is documented in cirrhosis, the role of neuronal NOS (nNOS) has not been investigated. The present study was carried out to specifically investigate the role of nNOS during liver cirrhosis. Specifically, physiological, biochemical, and molecular approaches were employed to evaluate the contribution of nNOS to the cirrhosis-related hyperdynamic circulation in CCl(4)-induced cirrhotic rats with ascites. Cirrhotic animals had a significant increase in water and sodium retention. In the aorta from cirrhotic animals, both nNOS protein expression and cGMP concentration were significantly elevated compared with control. Treatment of cirrhotic rats for 7 days with the specific nNOS inhibitor 7-nitroindazole (7-NI) normalized the low SVR and mean arterial pressure, elevated cardiac index, and reversed the positive sodium balance. Increased plasma arginine vasopressin concentrations in the cirrhotic animals were also repressed with 7-NI in association with diminished water retention. The circulatory changes were associated with a reduction in aortic nNOS expression and cGMP. However, 7-NI treatment did not restore renal function in cirrhotic rats (creatinine clearance: 0.76 +/- 0.03 ml. min(-1). 100 g body wt(-1) in cirrhotic rats vs. 0.79 +/- 0.05 ml. min(-1). 100 g body wt(-1) in cirrhotic rats+7-NI; P NS. ). Taken together, these results indicate that nNOS-derived NO contributes to the development of the hyperdynamic circulation and fluid retention in cirrhosis.

Degree of hippocampal atrophy is not related to a history of febrile seizures in patients with proved hippocampal sclerosis

OBJECTIVES

To examine the degree of hippocampal atrophy in patients with temporal lobe epilepsy and proved hippocampal sclerosis to determine whether or not patients with febrile seizures have more severe hippocampal atrophy. To determine whether or not there is a relation between age of seizure onset, duration of temporal lobe epilepsy, or seizure frequency, and severity of hippocampal atrophy.

METHODS

Hippocampal volumes were measured from volumetrically acquired MR images in 77 consecutive surgical patients with temporal lobe epilepsy (37 febrile seizures (FS)+, 40 FS-) with proved hippocampal sclerosis, and compared with 98 controls.

RESULTS

Ipsilateral and contralateral hippocampal volumes were not significantly different between the FS+ and FS- groups. There was no difference in the age of onset of habitual seizures, duration of epilepsy, or age at the time of surgery, between these groups. No clinically significant correlations were found between hippocampal volumes and age of onset of first non-febrile seizure, duration of temporal lobe epilepsy, or complex partial and secondarily generalised seizure frequency, in patients with and without febrile seizures.

CONCLUSIONS

Although febrile seizures was associated with hippocampal sclerosis in 48% of patients in this surgical series, the degree of MRI determined hippocampal atrophy was not related to a history of such seizures. The results do not support the view that febrile seizures cause more severe hippocampal sclerosis and are consistent with the hypothesis that hippocampal sclerosis is a pre-existing abnormality.

High direct estimate of the mutation rate in the mitochondrial genome of Caenorhabditis elegans

Mutations in the mitochondrial genome have been implicated in numerous human genetic disorders and offer important data for phylogenetic, forensic, and population genetic studies. Using a long-term series of Caenorhabditis elegans mutation accumulation lines, we performed a wide-scale screen for mutations in the mitochondrial genome that revealed a mutation rate that is two orders of magnitude higher than previous indirect estimates, a highly biased mutational spectrum, multiple mutations affecting coding function, as well as mutational hotspots at homopolymeric nucleotide stretches.

Salicylic acid has a role in regulating gene expression during leaf senescence

Leaf senescence is a complex process that is controlled by multiple developmental and environmental signals and is manifested by induced expression of a large number of different genes. In this paper we describe experiments that show, for the first time, that the salicylic acid (SA)-signalling pathway has a role in the control of gene expression during developmental senescence. Arabidopsis plants defective in the SA-signalling pathway (npr1 and pad4 mutants and NahG transgenic plants) were used to investigate senescence-enhanced gene expression, and a number of genes showed altered expression patterns. Senescence-induced expression of the cysteine protease gene SAG12, for example, was conditional on the presence of SA, together with another unidentified senescence-specific factor. Changes in gene expression patterns were accompanied by a delayed yellowing and reduced necrosis in the mutant plants defective in SA-signalling, suggesting a role for SA in the cell death that occurs at the final stage of senescence. We propose the presence of a minimum of three senescence-enhanced signalling factors in senescing leaves, one of which is SA. We also suggest that a combination of signalling factors is required for the optimum expression of many genes during senescence.

Comparison of hyperventilation and inhaled nitric oxide for pulmonary hypertension after repair of congenital heart disease

BACKGROUND

Pulmonary hypertension is associated with congenital heart lesions with increased pulmonary blood flow. Acute increases in pulmonary vascular resistance (PVR) occur in the postoperative period after repair of these defects. These increases in PVR can be ablated by inducing an alkalosis with hyperventilation (HV) or bicarbonate therapy. Studies have shown that these patients also respond to inhaled nitric oxide (iNO), but uncertainty exists over the relative merits and undesirable effects of HV and iNO.

HYPOTHESIS

Alkalosis and iNO are equally effective in reducing PVR and pulmonary artery pressure (PAP) in children with pulmonary hypertension after open heart surgery.

SETTING

Critical care unit of a tertiary care pediatric hospital.

DESIGN

Prospective, randomized, crossover design.

PATIENTS

Twelve children with a mean PAP > 25 mm Hg at normal pH after biventricular repair of congenital heart disease.

INTERVENTIONS

Patients were assigned to receive iNO or HV (pH > 7.5) in random order, and the effect on hemodynamics was measured. Each treatment was administered for 30 mins with a 30-min washout period between treatments. Finally, both treatments were administered together to look for a possible additive effect.

MEASUREMENTS AND MAIN RESULTS

Cardiac output and derived hemodynamic parameters using the dye dilution technique. Hyperventilation, achieved by an increase in ventilator rate without a change in mean airway pressure, decreased Pa(CO2) from a mean (SD) of 43.7+/-5.3 to 32.3+/-5.4 mm Hg and increased pH from 7.40+/-0.04 to 7.50+/-0.03. This significantly altered both pulmonary and systemic hemodynamics with a reduction in PAP, PVR, central venous pressure, and cardiac output and an increase in systemic vascular resistance. In comparison, iNO selectively reduced PAP and PVR only. The reduction in PVR was comparable between treatments, although addition of iNO to HV resulted in a small additional reduction in PVR. An additional decrease in PAP was seen when HV was added to iNO, attributable to a reduction in cardiac output rather than a further decrease in PVR.

CONCLUSIONS

Inhaled NO and HV are both effective at lowering PAP and PVR in children with pulmonary hypertension after repair of congenital heart disease. The selective action of iNO on the pulmonary circulation offers advantages over HV because a decrease in cardiac output and an increase in SVR are undesirable in the postoperative period.

First trimester ultrasound with nuchal translucency measurement for Down syndrome risk estimation using software developed by the Fetal Medicine Foundation, United Kingdom--the first 2000 examinations in Newcastle, New South Wales, Australia

In September 1997 screening for Down syndrome using first trimester ultrasound to measure nuchal translucency, with risk estimation by the software program developed in the United Kingdom by the Fetal Medicine Foundation, was introduced in Newcastle, New South Wales. In the first 2,000 such risk estimations 134 women (6.7 %) were screen positive (with a risk of greater than 1 in 300 at that gestation for Trisomy 21). In the first 1,000 of these 2,000 fetuses delivered thus far there were 8 cases of Trisomy 21, 2 of Trisomy 18 and 1 of 47 XXX. Nine of these 11 were screen positive, the only false negative results being for 2 cases of Trisomy 21. The detection rate for Trisomy 21 was 6 out of 8 (75%) and for every case of Trisomy 21 (Down Syndrome) detected by this process, 11.3 invasive tests would have been needed to make that diagnosis in a screen positive woman.

Comparison and reproducibility of fast and conventional spoiled gradient-echo magnetic resonance sequences in the determination of knee cartilage volume

Quantitation of articular cartilage by magnetic resonance imaging and three-dimensional reconstruction has been validated and is likely to be a useful outcome measure in clinical trials of arthritis. The cost of magnetic resonance imaging is largely dependent on scanning time. The aim of this study was to compare a fast spoiled gradient-echo sequence magnetic resonance imaging scanning protocol, which takes 5 minutes and 44 seconds, with the standard, previously validated spoiled gradient-echo sequence protocol, which takes 11 minutes and 56 seconds, in the measurement of knee cartilage volume. Cartilage volumes calculated from the standard and fast magnetic resonance imaging sequences were similar. The median absolute percentage overestimation or underestimation of the cartilage volume with the fast sequence for 10 normal subjects was 2.5, 4.1, and 3.2% for patellar, femoral, and tibial cartilage, respectively. For eight subjects with osteoarthritis, the percentages were 4.3 and 3.9% for femoral and tibial cartilage, respectively. The fast spoiled gradient-echo sequence protocol had very high intra-rater and inter-rater reproducibility in normal subjects and in those with osteoarthritis. Because the cost of magnetic resonance imaging scanning is largely determined by scan time, the faster scanning protocol means that the cost of estimates of knee cartilage volume can be significantly reduced, thus increasing the feasibility of this methodology.

Effect of neonatal gonadotropin-releasing hormone antagonist administration on sertoli cell number and testicular development in the marmoset: comparison with the rat

The primary purpose of this study was to establish whether Sertoli cells proliferate in the neonatal period in the marmoset monkey (Callithrix jacchus) and whether administration of a long-acting GnRH antagonist (GnRHa) during this phase induced any transient or permanent effects on Sertoli cell number or on any other aspect of testicular development. Male marmoset co-twins (n = 9) were treated during Weeks 1-14 with either vehicle or GnRHa. Four sets of co-twins were examined at Weeks 18-22 (start of infancy) and 5 sets in adulthood (92+ wk), and Sertoli cell number was determined using either the nucleator or optical disector methods; other testicular morphometric analyses (e.g., germ cell volume, Leydig cell volume) used standard point-counting. Data for the marmoset were compared with that obtained in similarly treated rats. Sertoli cell number in marmosets treated neonatally with GnRHa was reduced by 35% compared with that of controls at Weeks 18-22 but was comparable to control values in adulthood. However, seminiferous epithelium volume was reduced significantly in adult marmosets treated neonatally with GnRHa, and there was a tendency for reduced germ cell volume per Sertoli cell. In the same animals, there was significant expansion of the interstitium and an increase in Leydig cell volume per testis when compared with co-twin controls; a similar increase in Leydig cell volume was evident in adult rats treated neonatally with GnRHa. Comparison of Sertoli cell numbers in 6 infantile (18-24 wk) and 10 adult marmosets showed that adult numbers of Sertoli cells were present by the start of infancy but, unlike rats, marmosets were still able to replicate Sertoli cells beyond this period. However, marmoset Sertoli cells supported only approximately 20% of the germ cell volume supported by rat Sertoli cells, indicative of poor efficiency of spermatogenesis, as shown previously in the human. This finding, together with the demonstration of a temporal pattern of Sertoli cell replication similar to that in the human, supports the use of marmosets as a model for human male testicular development and function.