A brighter shade of future climate on Himalayan musk deer Moschus leucogaster

Himalayan musk deer (Moschus leucogaster) is classified as an endangered species by IUCN with a historically misunderstood distribution due to misidentification with other species of musk deer, Moschus spp. Taking advantage of recent genetic analyses confirming the species of various populations in Nepal and China, we produced an accurate estimate of the species' current and future distribution under multiple climate change scenarios. We collected high-quality occurrence data using systematic surveys of various protected areas of Nepal to train species distribution models. The most influential determinants of the distribution of Himalayan musk deer were precipitation of the driest quarter, temperature seasonality, and annual mean temperature. These variables, and precipitation in particular, determine the vegetation type and structure in the Himalaya, which is strongly correlated with the distribution of Himalayan musk deer. We predicted suitable habitats between the Annapurna and Kanchenjunga region of Nepal Himalaya as well as the adjacent Himalaya in China. Under multiple climate change scenarios, the vast majority (85-89%) of current suitable sites are likely to remain suitable and many new areas of suitable habitat may emerge to the west and north of the current species range in Nepal and China. Two-thirds of current and one-third of future suitable habitats are protected by the extensive network of protected areas in Nepal. The projected large gains in suitable sites may lead to population expansion and conservation gains, only when the threat of overexploitation and population decline is under control.

Himalayan musk deer ( Moshcus leucogaster ) behavior at latrine sites and their implications in conservation

Elusive species often use latrines which also serves as communication and information hubs. Thus, studying behavior at latrines may provide critical insights into the species’ ecology and behavior. While it is established that musk deer use latrines for defecating, very little is known about the endangered Himalayan musk deer (Moschus leucogaster) and their latrines. We examined musk deer behavior from the various video clips lasting 238 min altogether, captured at latrine sites during both breeding and non‐breeding seasons in the Annapurna Conservation Area of Nepal. A total of 428 visits by musk deer and 479 behavioral events by them were captured. We constructed an ethogram to describe musk deer behavior and compared behavior across individuals and sex using parametric and non‐parametric tests. We found that musk deer are crepuscular and nocturnal animals. Both male and female musk deer repeatedly and independently visited shared latrine sites as well as exclusively used latrine sites. The proportion of male musk deer visited latrine sites were significantly higher than that of female musk deer. Hence, male musk deer were found more active (>2 times) than females during both seasons. The most frequently observed behavioral activities at the latrine sites were defecating, sniffing and browsing, followed by scrapping and covering, and ignoring the latrine sites. The defecating and sniffing activity were performed throughout breeding and non‐breeding seasons to establish communication among peers and to claim territory. Based on the behaviors observed at the latrine sites, we can presume that Himalayan musk deer likely use latrines to convey various messages, including personality, maturity, sexual status, and territory marking among conspecifics. These findings of this study can be used for the conservation of musk deer in its natural habitat and replicated in captivity to enhance breeding performance that improves long‐term conservation prospects for this species.

Mercury distribution in the East Himalayas: Elevational patterns in soils and non-volant small mammals

Mercury (Hg), as a global pollutant, its contamination has been documented in environmental compartments of the Himalayan region. However, little research exists regarding to Hg accumulation in terrestrial wildlife, as well as its driving factors. In this study, surface soil and small mammals were collected in the Lebu Valley, East Himalayas of China, in order to measure the uptake of the long-distance transported Hg along an elevational gradient approximately from 2300 to 5000 m a.s.l. The soil Hg concentrations were measured and predicted mostly by vegetation type as well as soil organic matter, while the Hg in hair of small mammals (Muridae and Cricetidae) showed deeply influenced by soil Hg. Notably, combined with the field survey data, soil and hair Hg were both enhanced in low and mid-elevations, which overlapped the distribution ranges of a majority of mammals. Overall, this indicates that Hg contamination in low- and mid-elevations poses a potential threat to the top predators that consuming small mammals directly or indirectly. Furthermore, our data advances the understanding of Hg dynamics in remote, high mountain ecosystems and provides baseline data for biomonitoring for reduction of Hg emission globally.

Climate-driven elevational variation in range sizes of vascular plants in the central Himalayas: A supporting case for Rapoport's rule

A fundamental yet controversial topic in biogeography is how and why species range sizes vary along spatial gradients. To advance our understanding of these questions and to provide insights into biological conservation, we assessed elevational variations in the range sizes of vascular plants with different life forms and biogeographical affinities and explored the main drivers underlying these variations in the longest valley in China's Himalayas, the Gyirong Valley. Elevational range sizes of vascular plants were documented in 96 sampling plots along an elevational gradient ranging from 1,800 to 5,400 m above sea level. We assessed the elevational variations in range size by averaging the range sizes of all recorded species within each sampling plot. We then related the range size to climate, disturbance, and the mid-domain effect and explored the relative importance of these factors in explaining the range size variations using the Random Forest model. A total of 545 vascular plants were recorded in the sampling plots along the elevational gradient. Of these, 158, 387, 337, and 112 were woody, herbaceous, temperate, and tropical species, respectively. The range size of each group of vascular plants exhibited uniform increasing trends along the elevational gradient, which was consistent with the prediction of Rapoport's rule. Climate was the main driver of the increasing trends of vascular plant range sizes in the Gyirong Valley. The climate variability hypothesis and mean climate condition hypothesis could both explain the elevation-range size relationships. Our results reinforce the previous notion that Rapoport's rule applies to regions where the influence of climate is the most pronounced, and call for close attention to the impact of climate change to prevent species range contraction and even extinction due to global warming.

Projected distribution and climate refugia of endangered Kashmir musk deer Moschus cupreus in greater Himalaya, South Asia

Kashmir musk deer Moschus cupreus (KMD) are the least studied species of musk deer. We compiled genetically validated occurrence records of KMD to construct species distribution models using Maximum Entropy. We show that the distribution of KMD is limited between central Nepal on the east and north-east Afghanistan on the west and is primarily determined by precipitation of driest quarter, annual mean temperature, water vapor, and precipitation during the coldest quarter. Precipitation being the most influential determinant of distribution suggests the importance of pre-monsoon moisture for growth of the dominant vegetation, Himalayan birch Betula utilis and Himalayan fir Abies spectabilis, in KMD's preferred forests. All four Representative Concentration Pathway Scenarios result an expansion of suitable habitat in Uttarakhand, India, west Nepal and their associated areas in China in 2050s and 2070s but a dramatic loss of suitable habitat elsewhere (Kashmir region and Pakistan-Afghanistan border). About 1/4th of the current habitat will remain as climate refugia in future. Since the existing network of protected areas will only include a tiny fraction (4%) of the climatic refugia of KMD, the fate of the species will be determined by the interplay of more urgent short-term forces of poaching and habitat degradation and long-term forces of climate change.

Ecological correlates of Himalayan musk deer Moschus leucogaster

Himalayan musk deer (Moschus leucogaster; hereafter musk deer) are endangered as a result of poaching and habitat loss. The species is nocturnal, crepuscular, and elusive, making direct observation of habitat use and behavior difficult. However, musk deer establish and repeatedly use the same latrines for defecation. To quantify musk deer habitat correlates, we used observational spatial data based on presence-absence of musk deer latrines, as well as a range of fine spatial-scale ecological covariates. To determine presence-absence of musk deer, we exhaustively searched randomly selected forest trails using a 20-m belt transect in different study sites within the Neshyang Valley in the Annapurna Conservation Area. In a subsequent way, study sites were classified as habitat or nonhabitat for musk deer. A total of 252 plots, 20 × 20 m, were systematically established every 100 m along 51 transects (each ~0.5 km long) laid out at different elevations to record a range of ecological habitat variables. We used mixed-effect models and principal component analysis to characterize relationships between deer presence-absence data and habitat variables. We confirmed musk deer use latrines in forests located at higher elevations (3,200-4,200 m) throughout multiple seasons and years. Himalayan birch (Betula utilis) dominated forest, mixed Himalayan fir (Abies spectabilis), and birch forest were preferred over pure Himalayan fir and blue pine (Pinus wallichiana) forest. Greater crown cover and shrub diversity were associated with the presence of musk deer whereas tree height, diameter, and diversity were weakly correlated. Topographical attributes including aspect, elevation, distance to water source, and slope were also discriminated by musk deer. Over- and understory forest management can be used to protect forests likely to have musk deer as predicted by the models to ensure long-term conservation of this rare deer.

Awake Fiberoptic Intubation in Cervical Spine Injury: A Comparison between Atomized Local Anesthesia versus Airway Nerve Blocks

Background In cooperative patients with cervical spine injury, awake fiberoptic intubation is an excellent option for elective and semi urgent situations. It allows documentation of neurologic examination before and after intubation and surgical positioning. We have compared anesthesia of airway by nerve block and the local anesthesia atomizer undergoing awake fiberoptic intubation in cervical spine injury patients, in terms of the intubation time and discomfort. Objective To compare the intubation time and discomfort in patient with cervical spine injury with anticipated difficult airway potential to aggravate pre-existing injury undergoing awake fiberoptic intubation, based on cough and gag scores, between anesthesia of airway by (transtracheal and bilateral superior laryngeal) nerve block with local anesthetic agent and the local anesthesia atomizer. Method After institutional ethical approval and having informed written consent, 30 patients scheduled for elective surgery who require awake fiberoptic intubation, were included in the study. Patients were allotted by computer-generated random series into two groups; Group N received nerve block (transtracheal and bilateral recurrent laryngeal nerve block) and Group A received atomized lignocaine. Result The time taken for awake fiberoptic intubation was significantly lower in nerve blocks group as compared with the atomizer group [Group N: 90.2±11.7secs and Group A: 210.4±10.6 secs (p=0.041)]. Atomizer group had an increased coughing and gagging episodes than nerve block group [Group N: one patient, Group A: 11 patients (p=0.006)]. Ease of intubation and patient comfort were significantly better in nerve block group. Demographic and hemodynamic parameters were comparable in the two groups. Conclusion The nerve blocks (bilateral superior laryngeal and transtracheal recurrent laryngeal) provides adequate airway anesthesia, lesser patient discomfort, and faster intubation to aid in awake fiberoptic intubation in patients with anticipated difficult airway as compared to topical anesthesia using atomizer.

The Prevalence of Clinically Significant Prostate Cancer According to Commonly Used Histological Thresholds in Men Undergoing Template Prostate Mapping Biopsies

PURPOSE

Transrectal prostate biopsies are inaccurate and, thus, the prevalence of clinically significant prostate cancer in men undergoing biopsy is unknown. We determined the ability of different histological thresholds to denote clinically significant cancer in men undergoing a more accurate biopsy, that of transperineal template prostate mapping.

MATERIALS AND METHODS

In this multicenter, cross-sectional cohort of men who underwent template prostate mapping biopsies between May 2006 and January 2012, 4 different thresholds of significance combining tumor grade and burden were used to measure the consequent variation with respect to the prevalence of clinically significant disease.

RESULTS

Of 1,203 men 17% (199) had no previous biopsy, 38% (455) had a prior negative transrectal ultrasound biopsy, 24% (289) were on active surveillance and 21% (260) were seeking risk stratification. Mean patient age was 63.5 years (SD 7.6) and median prostate specific antigen was 7.4 ng/ml (IQR 5.3-10.5). Overall 35% of the patients (424) had no cancer detected. The prevalence of clinically significant cancer varied between 14% and 83% according to the histological threshold used, in particular between 30% and 51% among men who had no previous biopsy, between 14% and 27% among men who had a prior negative biopsy, between 36% and 74% among men on active surveillance, and between 47% and 83% among men seeking risk stratification.

CONCLUSIONS

According to template prostate mapping biopsy between 1 in 2 and 1 in 3 men have prostate cancer that is histologically defined as clinically significant. This suggests that the commonly used thresholds may be set too low.

HP1 proteins--what is the essential interaction?

There are three mammalian HP1 genes, Cbx5 (encoding HP1alpha), Cbx1 (encoding HP1beta) and Cbx3 (encoding HP1gamma). Despite their high degree of sequence homology mutational analysis has revealed different phenotypes indicating that they possess different functions. Notably, the Cbx1 mutation is lethal in its homozygous condition. The Cbx1 null phenotype is therefore more severe than the Suv(3)9h1/h2 double-mutant mouse, indicating that the essential function of the Cbx1 gene product, HP1beta, is likely to lie outside its interaction with the heterochromatic H3K9me3 determinant of the "histone code" imposed by the Suv(3)9h1/h2 HMTases. Comparisons of HPI mutants in flies and fungi with corresponding mutations in Suv(3)9 genes show that HP1 mutations are invariably more severe than mutation in Suv(3)9 genes. The implications of these data for HP1 function are discussed.

Variation in umami taste perception in the German and Norwegian population

In this study, we investigated inter-individual differences in sensitivity to mono-sodium glutamate (MSG) and elucidated the familiarity to umami taste in two European populations. The study consisted of two parts: (1) a survey based on questionnaire and (2) psychophysical screening for inter-individual variation of MSG sensitivity. The psychophysical tests revealed that 3.2% of the German participants and 4.6% of the Norwegian participants were potential non-tasters of MSG. In conclusion, our study confirms inter-individual differences in sensitivity to MSG in humans.

Achieving reimbursement for regenerative medicine products in the USA

Achieving reimbursement for regenerative medicine products is potentially a greater challenge than gaining US FDA approval, making it a decisive factor in the success or failure of small businesses. However, the mechanisms by which reimbursement is achieved are still seen as something of a ‘black box’, especially to those outside of the USA. This report aims to provide insights into the mechanisms of reimbursement and variety of payers in the USA, and to act as a starting point for a successful US reimbursement strategy. Fundamental concepts such as coverage, payment and coding are explained and linked with the factors that potentially determine the successful reimbursement of regenerative medicine products, including cost of goods and clinical study design. Finally, important considerations for the design of clinical studies that satisfy both the payers and the FDA are discussed and the key elements of a successful company strategy identified.

Experience with plaque excision and dermal grafting in the surgical treatment of Peyronie's disease

INTRODUCTION

Peyronie's disease is a common cause of sexual dysfunction. We assess the technique of plaque excision and dermal grafting for the treatment of Peyronie's disease.

METHODS

A total of 11 patients, aged 38-55 years, were operated for Peyronie's disease. All patients had stable plaque on the dorsum or dorsolateral aspect of the penile shaft. All patients had penile curvature, nine (81.8 percent) had painful erections, six (54.5 percent) had penile pain and three (27.3 percent) had erectile dysfunction. All suffered difficulty in intercourse. We performed plaque excision and dermal grafting. Main outcome measures were relief of penile pain, relief of painful erection, performance of satisfactory coitus and straight penis while erection.

RESULTS

All patients had relief of penile pain and painful erection. Nine (81.8 percent) patients had straight penis and had satisfactory coitus. Two (18.2 percent) patients suffered postoperative erectile dysfunction which was mild and responded to Sildenafil tabs.

CONCLUSION

Although experience with this technique is limited, the initial results are encouraging. We found this technique feasible with satisfactory results.

Use of tissue ink to maintain identification of individual cores on needle biopsies of the prostate

BACKGROUND

There is an increasing necessity to extract the maximum amount of information, beyond even a cancer diagnosis, from prostate biopsies. Thus, maintaining site-specific information regarding individual biopsy cores might be critical.

AIM

To evaluate the applicability of employing tissue ink to maintain the identity of individual prostatic biopsy cores.

METHOD

In this ongoing study, 12 core prostate biopsy specimens are sent to the laboratory in individual pots labelled according to anatomical site. The specimens are placed in two separate multi-compartment cassettes. They are inked with different colours to identify the site of origin from each lobe. The cassettes are then processed with a single paraffin block for each side; the six cores from each side can be mounted on a single slide.

RESULTS

The different colours used adhere well to the biopsy cores, thus maintaining the identity of each core. Six cores from each side are embedded in a single paraffin block and examined on a single slide, making it cost-effective, while maintaining high quality, accurate histopathological information.

CONCLUSION

Differential inking of prostate biopsy cores is an easily applicable method that is cost-effective and provides tumour location information. Prostate biopsy data archived to maintain individual core information might be used to determine applicability of such information to predict extra-capsular extension by correlating with imaging and radical prostatectomy findings, and for treatment planning.

Bilateral single system ectopic ureters: case report with literature review

Bilateral single system ureteral ectopia (BSSEU) is one of the rarest entities in urology, with less than 80 cases reported so far. Incontinence resulting from the underlying anomaly can be devastating to the child. It is generally agreed that suitable urinary continence and long dry intervals are seldom obtainable because of poorly developed trigone and bladder neck area. We herein report a case of BSSEU managed by bilateral ureteric reimplantation, achieving satisfactory continence and bladder capacity without the need for urinary diversion or bladder neck reconstruction.

Primary cavernous hemangioma of the glans penis: rare case report with a review of the literature

Hemangiomas of the urinary tract are rare lesions, and those of the glans penis are even rarer. A 23-year-old man with a hemangioma of the glans penis treated successfully with intralesional sclerotherapy is presented. Other options for the management of this disorder are discussed.

Effects of estradiol-17beta and 17alpha, 20beta-dihydroxy-4-pregnen-3-one on different phospholipids metabolism and histological changes in ovary during reproductive growth in the catfish, Heteropneustes fossilis (Bloch)

Effect of cumulative doses of estradiol -17beta (E2-7, 14 and 28 mg/kg body weight) and 17alpha, 20beta-dihydroxy-4-pregnen-3-one (17alpha,20betaP-7, 14 and 28 mg/kg body weight) on total phospholipids (TP) and various phospholipids- phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidylethanolamine (PE) on liver plasma and ovary were investigated during the reproductively active preparatory and prespawning phases of the annual reproductive cycle in the freshwater female catfish, H. fossilis. The effect of E2 on TP was generally stimulatory and has pronounced effect than 17alpha,20betaP during both the phases. The levels of PC was promoted high during prespawning phase by E2 comparatively very less than by 17alpha, 20betaP in studied tissues during both the phases. The levels of PS after E2 treatments was maximum in all tissues during prespawning phase whereas 17alpha,20betaP was effective only in liver during this phase. The PI was elevated in liver during preparatory phase but its elevation was in all studied tissues during prespawning phase after E2 treatments. The levels of PI was most effective in ovary during preparatory phase in response to 17alpha,20betaP. The levels of PE was declined in liver but elevated in ovary after E2 treatments during both the phases. Treatments of E2 during preparatory phase showed greater number of vitellogenic oocytes as compared to 17alpha,20betaP treatments. The present finding has demonstrated that estradiol-17beta has more pronounced effects than the 17alpha,20beta P in regulation of different phospholipids and ovarian recrudescence during reproductively active phases and among the phospholipids the PC is the main phospholipids of vitellogenin/ovarian lipids in H. fossilis.

Dorsal onlay buccal mucosal graft urethroplasty in long anterior urethral stricture

OBJECTIVE

To assess the success of buccal mucosal graft (BMG) urethroplasty by the dorsal onlay technique in long anterior urethral stricture (> 2 cm long) through the midline perineal incision.

MATERIALS AND METHODS

From January 1998 to December 2003, 43 patients with long anterior urethral strictures were managed by dorsal onlay BMG urethroplasty. After voiding trial, they were followed up at 3 months with uroflowmetry, retrograde urethrogram (RGU) and American Urological Association symptoms score (AUA symptoms scores). Successful outcome was defined as normal voiding with a maximum one attempt of visual internal urethrotomy (VIU) after catheter removal. Patients were further followed-up with uroflowmetry at 3 months interval and RGU every 6 months interval.

RESULTS

Mean stricture length was 4.8 cm (range 3 to 9 cm) and mean follow up was 48 months (range 12 to 84 months). Only five patients were found to develop stricture at anastomotic site, during follow-up. Two of them voided normally after single attempt of VIU. Other three patients (6.9%) required further open surgery or repeat VIU during follow up and were considered as failure.

CONCLUSION

Dorsal onlay BMG urethroplasty is a simple technique with good surgical outcome.

A decade's experience with vesicovaginal fistula in India

A retrospective analysis of 252 cases of vesicovaginal fistulae was done to analyse its etio-pathology and management in an Indian population. After a thorough evaluation, different techniques of fistula closure were used for repair and the results were listed. The main outcome measures were the etiology of the fistula, need for tissue interposition and cure rate per repair as well as the overall cure rate. We compared our results with literature and concluded that simple and small fistulae should be repaired with layered closure. All complicated fistulae should be repaired with tissue interposition or tissue graft. This is the first study from India compiling 10 years of experience on vesicovaginal fistula.

POST CAESAREAN VESICOUTERINE FISTULAE - YOUSSEF SYNDROME: OUR EXPERIENCE AND REVIEW OF PUBLISHED WORK

OBJECTIVE

To analyse the incidence, symptomatology, diagnosis and therapeutic aspects of Youssef syndrome (post caesarean vesicouterine fistula), and to review relevant published work.

METHODS

A retrospective study from the urosurgical unit of a tertiary care referral hospital was carried out. In a retrospective analysis of urogenital fistulae over 10 years, we identified 14 patients with uterovesical fistulae, resulting from caesarean section. All the patients were evaluated by history, physical examination, radiological tests and cystoscopy. All patients underwent transperitoneal repair of these fistulae with omental interposition. Results of surgery were evaluated by absence of cyclic haematuria, stoppage of urinary incontinence, and achievement of fertility.

RESULTS

A total of 12 patients who had minimum follow up was included in the present study. The results showed that 50% of the fistulae resulted from emergency caesarean operation with 58% of patients presenting after their second caesarean section. The mean age of the patients was 19 years (range 15-29) and mean duration of symptoms was 7 months (range 3-16). Menouria and amenorrhoea were predominant presenting symptoms. The results of surgical treatment were excellent with good continence and resolution of the cyclic haematuria. Three pregnancies (37.5%) which resulted in elective caesarean section were recorded.

CONCLUSION

Vesicouterine fistulae, despite being infrequent, are no longer a rare diagnosis and are most commonly secondary to lower segment caesarean section. With patient history and selected investigations diagnosis is relatively easy. The surgical repair of these fistulae is standard treatment, especially with delayed fistulae with achievement of total continence, and complete resolution of cyclic haematuria. Meticulous practice of obstetric and surgical principles during caesarean section can prevent the formation of these fistulae.

Safety and Efficacy of Ureteroscopic Lithotripsy for Ureteral Calculi Under Sedoanalgesia – A Prospective Study

OBJECTIVE

To establish the safety and efficacy of ureteroscopic lithotripsy (URSL) under sedoanalgesia.

PATIENTS AND METHODS

This study was conducted at Department of Urology (Banaras Hindu University, India) among 124 patients with ureteral stones, between July 2000 and August 2003. Majority of the patients (59.68%) presented with lower ureteric calculi, 24.19% presented with upper ureteric calculi and 16.13% had middle ureteric calculi. All patients were given injection diclofenac sodium (75 mg) promethazine hydrochloride (12.5 mg) deep intramuscular 30 minutes the before procedure. Injection midazolam 0.03 mg/kg body weight slowly given intravenously immediately before the procedure for achieving sedation. Injection fentanyl 50 mcg intravenously given slowly just before introducing the ureteroscope into ureter for achieving intravenous analgesia. Patients were observed for few hours after completion of procedure and oral questions were asked as per proforma, which included tolerance, intensity of pain and percentage of pain experienced by the patients. Patients were discharged thereafter.

RESULTS

87.10% of patients opined that the procedure was acceptable. Only 4.84% opined this procedure was painful. According to present pain intensity score (PPI) in this study 79.03 patients experienced only mild pain, 11.29% cases rated procedure as discomforting, 6.45 rated procedure as distressing and only 3.23% rated as horrible procedure. As per visual analogue scale for assessment of pain 80.65 of cases rated only 20% pain score (in a scale of 0-100). 9.68% cases rated 30% and 6.45% rated 50%. Only two patients in middle ureteric group rated 100% pain. Overall success rate in fragmenting stone was 91.94, where as for lower ureteric calculi it was 97.30%; for upper and, middle ureteric calculi it was 86.66% and 80%, respectively.

CONCLUSION

Ureteroscopic lithotripsy can be performed on day care basis under sedoanalgesia which is fairly tolerated by the patients with unremarkable complications and difficulty.

Messenger RNA electroporation is highly efficient in mouse embryonic stem cells: successful FLPe- and Cre-mediated recombination

Development of efficient short-term gene transfer technologies for embryonic stem (ES) cells is urgently needed for various existing and new ES cell-based research strategies. In this study, we present a highly efficient, nonviral non-DNA technology for genetic loading of mouse ES cells based on electroporation of defined mRNA. Here, we show that mouse ES cells can be efficiently loaded with mRNA encoding a green fluorescent reporter protein, resulting in a level of at least 90% of transgene expression without loss of cell viability and phenotype. To show that transgenes, introduced by mRNA electroporation, exert a specific cellular function in transfected cells, we electroporated stably transfected ES cell lines with mRNA encoding FLPe or Cre recombinase proteins in order to excise an FRT- or LoxP-flanked reporter gene. The results, as determined by the disappearance and/or appearance of a fluorescent reporter gene expression, show that FLPe and Cre recombinase proteins, introduced by mRNA electroporation, efficiently exert their function without influence on further culture of undifferentiated ES cell populations and their ability to differentiate towards a specific lineage.

Povidone iodine and dextrose solution combination sclerotherapy in chyluria

OBJECTIVES

To evaluate the effectiveness of combination (povidone iodine and 50% dextrose) renal pelvic instillation sclerotherapy (RPIS) as a minimally invasive therapy for chyluria resistant to conservative treatment.

METHODS

A total of 50 patients with chyluria and hematochyluria (28 men and 22 women) were included in the study. Initially, all were offered conservative antifilarial drug therapy and dietary fat restriction. Intravenous urography was done in all cases to document normal renal functional status. In the patients in whom chyluria persisted after 3 weeks of conservative therapy, cystoscopic lateralization was done and a 5F open-ended ureteral catheter was positioned under local anesthesia. The same was left attached to a 16F Foley catheter for 3 days of RPIS. A solution of 5 mL of 5% povidone iodine and 5 mL of 50% dextrose was instilled twice a day with the patient in the Trendelenburg position for 3 days. In cases of bilateral efflux, the dominant side was treated first. The opposite side was subjected to a similar instillation sclerotherapy schedule after 6 weeks if chyluria persisted.

RESULTS

Of the 50 patients, only 4 responded to conservative therapy. The remaining 46 patients underwent combination RPIS. The mean follow-up was 24 months. Complete remission of chyluria or hematochyluria occurred in 40 (87%) and persisted in 6 patients (13%). Of the 6 patients in whom symptoms persisted, 2 developed chyluria on the side opposite the one treated with RPIS. Another 2 patients developed recurrence on the same side after remaining asymptomatic for 6 months after RPIS. All four of these patients subsequently underwent chylolymphatic disconnection and nephropexy (two open and two laparoscopic) with a successful outcome. The final 2 patients with persistent symptoms were lost to follow-up.

CONCLUSIONS

Combination sclerotherapy using a 5% povidone iodine and 50% dextrose solution is a safe and cost-effective minimally invasive therapy for chyluria refractory to conservative treatment.

Serum p53 and bladder cancer: can serum p53 be used as a tumor marker?

The aim of this study was to find the correlation between serum p53 and carcinoma of the bladder and to investigate whether serum p53 protein can be used as a tumor marker for p53 gene alteration. The study included patients with carcinoma of the bladder and controls. Serum p53 protein estimation was done with an ELISA kit. There were 23 patients with superficial and 17 with invasive carcinoma. The median serum p53 was 31.5 U/ml in superficial and 41 U/ml in invasive cancer. This was significantly higher than the mean value (16.4 U/ml) of controls. Serum p53 rises in patients with carcinoma of the bladder and correlates with the grade of the disease . It can therefore be used as a tumor marker for bladder cancer.

Mucocutaneous lesions in transplant recipient in a tropical country

Dermatological manifestations are common in renal transplant patients, but differ markedly with ethnic group and geographical location. We studied mucocutaneous lesions in 54 renal allograft recipients (related donors = 30; unrelated donors = 24) living in tropical atmospheres. Their gender was 50 males, and 4 females ranging in age between 15 and 63 years (mean = 37.84 years). The mean duration of follow-up was 124 months (range = 4 to 173 months). All patients received kidneys from living donors and were kept on immunosupression with mean daily doses of prednisolone, azathioprine, and cyclosporine of 10.2 mg, 68.6 mg, and 252 mg, respectively. The mean trough concentration of cyclosporine was 185 ng/mL. The mucocutaneous lesions were divided into four groups: drug-induced (n = 24, 44.4%), fungal (n = 18, 33.3%), viral (n = 9, 16.6%), and bacterial (n = 10, 18.5%). Cushingoid features, gum hypertrophy, and hypertrichosis were seen in 7 (12.9%) patients. Steroid acne was seen in three cases. Pityriasis versicolor was the most common (20.3%) fungal infection of the skin. In addition, Tinea unguium and mucocutaneous candidiasis were noted in four and three cases respectively. Herpes virus infection (Herpes zoster 5; Herpes simplex 2) was noted in 7 (12.9%) cases. Chicken pox at 5 years posttransplant and cutaneous vasculitis associated with cytomegalovirus disease at 6 months posttransplant were seen in one case each. We have not seen warts in our patients. Pyogenic bacterial infection of skin in the form of abscess (n = 6), cellulitis (n = 3), and pyoderma (n = 1) were observed in 10 (18.5%) patients. Thus, drug-induced mucocutaneous side effects and skin fungal infections are the most common dermatological manifestations among renal transplant recipients living in a tropical country.

Filarial chyluria: Long-term experience of a university hospital in India

BACKGROUND

Filariasis is an endemic problem in various Indian states. We evaluated the results of long-term follow up (10-20 years) of patients with filarial chyluria.

METHODS

We conducted a retrospective analysis of 160 patients treated for filarial chyluria who presented to the Banaras Hindu University Hospital from 1982 to 1992. Eighty-four patients (52.5%) were treated using diethylcarbamazine (DEC) and a fat restricted diet and 76 patients (47.5%) underwent surgery. To examine the long-term effects of filarial chyluria we analysed data on post-treatment recurrence, weight gain, dietary freedom, chyluria free period and a number of other associated factors.

RESULTS

Previous history of filariasis or its complication was documented in 19% of patients. In 71% of cases, cystoscopy showed that chylous efflux was predominant in the left ureteric orifice. The long-term remission rate was 62% in the conservatively managed group (DEC + fat restricted diet), whereas 90% of patients in the operated group were cured. Postoperative recurrence rate was 10%. There was more weight gain and dietary freedom along with a longer chyluria free period in the operated group relative to the conservatively managed group.

CONCLUSIONS

Definitive surgical ablation of lymphatic urinary fistula is better than conservative medical management because it has a higher success rate, more dietary freedom and, therefore, better patient acceptability.

Artificial neural networks in predicting optimum renal stone fragmentation by extracorporeal shock wave lithotripsy: a preliminary study

OBJECTIVE

To assess the ability of artificial neural networks (ANNs) to predict optimum renal stone fragmentation in patients being managed by extracorporeal shock wave lithotripsy (ESWL).

PATIENTS AND METHODS

The study included 82 patients with renal stones who were being treated by ESWL. Data (input and output values) from 60 patients in whom there was optimum fragmentation of stones by ESWL were used for training the ANN. These data mainly included the 24-h urinary variables, the radiological features of the stone disease and the ESWL settings used. The predictability of the trained ANN was tested on 22 subsequent patients, by supplying the input variables of the 22 patients into the trained ANN and recording the output values (predicted values). After subjecting these patients to ESWL, the actual results (observed values) were recorded. The predicted and the observed values were then compared.

RESULTS

In the 22 patients in whom predictability was tested, the trained ANN predicted optimum fragmentation at < or = 13 000 shocks/stone (as per study protocol) in 17 and optimum fragmentation at> 13 000 shocks/stone in the other five. In the 17 patients (test set) where the trained ANN had predicted optimum fragmentation at < or = 13 000 shocks/stone, the optimum fragmentation was at that value, although the predicted and observed values were not identical. The overall correlation between the predicted and the observed values was 75.5% (correlation coefficient 0.7547) in these 17 patients. Of the other five patients, none had optimum fragmentation at < 13 000 shocks/stone, as predicted by the trained ANN, giving complete accuracy for this factor.

CONCLUSION

This was a pilot study, i.e. an initial attempt to use an ANN in this regard, and although there were few patients, such that it is not possible to make final recommendations, the overall predictability was approximately 75%. An encouraging outcome of the study was that the trained ANN identified patients unlikely to benefit from ESWL. Using a larger dataset and identifying more significant variables, while eliminating inputs with a negative effect, the efficiency and utility of this ANN can probably be enhanced and in future it might be possible to predict stone fragmentation with reasonable accuracy.

Exposure of infants to outdoor and indoor air pollution in low-income urban areas - a case study of Delhi

Indoor air pollution is potentially a very serious environmental and public health problem in India. In poor communities, with the continuing trend in biofuel combustion coupled with deteriorating housing conditions, the problem will remain for some time to come. While to some extent the problem has been studied in rural areas, there is a dearth of reliable data and knowledge about the situation in urban slum areas. The microenvironmental model was used for assessing daily-integrated exposure of infants and women to respirable suspended particulates (RSP) in two slums of Delhi - one in an area of high outdoor pollution and the other in a less polluted area. The study confirmed that indoor concentrations of RSP during cooking in kerosene-using houses are lesser than that in wood-using houses. However, the exposure due to cooking was not significantly different across the two groups. This was because, perhaps due to socioeconomic reasons, kerosene-using women were found to cook for longer durations, cook inside more often, and that infants in such houses stayed in the kitchen for longer durations. It was observed that indoor background levels during the day and at nighttime can be exceedingly high. We speculate that this may have been due to resuspension of dust, infiltration, unknown sources, or a combination of these factors. The outdoor RSP levels measured just outside the houses (near ambient) were not correlated with indoor background levels and were higher than those reported by the ambient air quality monitoring network at the corresponding stations. More importantly, the outdoor levels measured in this study not only underestimated the daily-integrated exposure, but were also poorly correlated with it.

The gene and pseudogenes of Cbx3/mHP1 gamma

The HP1 class of chromobox (Cbx) genes encode an evolutionarily conserved family of proteins involved in the packaging of chromosomal domains into a repressive heterochromatic state. The murine Cbx5, Cbx1 and Cbx3 genes encode the three mouse HP1 proteins, mHP1 alpha, -beta and -gamma respectively. Here, we report the cloning of the mouse Cbx3/HP1 gamma gene and the chromosomal localisation of Cbx3 and three Cbx3-related pseudogenes. The Cbx3 structural gene is located on mouse Chromosome 6, close to the Hoxa cluster. Two Cbx3 processed pseudogenes are separated by just 300 bp and are arranged in a head-to-tail configuration on Chromosome 13 while a third pseudogene is found on mouse Chromosome 4. The genomic intron-exon arrangement of Cbx3 is different from the conserved organisation of three other mammalian HP1 genes, Cbx1 (mHP1 beta), CBX3 (hHP1 gamma), and Cbx5 (mHP1 alpha) in that Cbx3 lacks an intron that is present in the others.

Histones H3/H4 form a tight complex with the inner nuclear membrane protein LBR and heterochromatin protein 1

We have recently shown that heterochromatin protein 1 (HP1) interacts with the nuclear envelope in an acetylation-dependent manner. Using purified components and in vitro assays, we now demonstrate that HP1 forms a quaternary complex with the inner nuclear membrane protein LBR and a sub-set of core histones. This complex involves histone H3/H4 oligomers, which mediate binding of LBR to HP1 and cross-link these two proteins that do not interact directly with each other. Consistent with previous observations, HP1 and LBR binding to core histones is strongly inhibited when H3/H4 are modified by recombinant CREB-binding protein, revealing a new mechanism for anchoring domains of under-acetylated chromatin to the inner nuclear membrane.

M31 and macroH2A1.2 colocalise at the pseudoautosomal region during mouse meiosis

Progression through meiotic prophase is associated with dramatic changes in chromosome condensation. Two proteins that have been implicated in effecting these changes are the mammalian HP1-like protein M31 (HP1β or MOD1) and the unusual core histone macroH2A1.2. Previous analyses of M31 and macroH2A1.2 localisation in mouse testis sections have indicated that both proteins are components of meiotic centromeric heterochromatin and of the sex body, the transcriptionally inactive domain of the X and Y chromosomes. This second observation has raised the possibility that these proteins co-operate in meiotic sex chromosome inactivation. In order to investigate the roles of M31 and macroH2A1.2 in meiosis in greater detail, we have examined their localisation patterns in surface-spread meiocytes from male and female mice. Using this approach, we report that, in addition to their previous described staining patterns, both proteins localise to a focus within the portion of the pseudoautosomal region (PAR) that contains the steroid sulphatase (Sts) gene. In light of the timing of its appearance and of its behaviour in sex-chromosomally variant mice, we suggest a role for this heterochromatin focus in preventing complete desynapsis of the terminally associated X and Y chromosomes prior to anaphase I.

Binding of heterochromatin protein 1 to the nuclear envelope is regulated by a soluble form of tubulin

We have previously shown that the mouse heterochromatin protein 1 homologue M31 interacts dynamically with the nuclear envelope. Using quantitative in vitro assays, we now demonstrate that this interaction is potently inhibited by soluble factors present in mitotic and interphase cytosol. As indicated by depletion and order-of-addition experiments, the inhibitory activity co-isolates with a 55-kDa protein, which binds avidly to the nuclear envelope and presumably blocks M31-binding sites. Purification of this protein and microsequencing of tryptic peptides identify it as alpha2/6:beta2-tubulin. Consistent with this observation, bona fide tubulin, isolated from rat brain and maintained in a nonpolymerized state, abolishes binding of M31 to the nuclear envelope and aborts M31-mediated nuclear envelope reassembly in an in vitro system. These observations provide a new example of "moonlighting," a process whereby multimeric proteins switch function when their aggregation state or localization is altered.

Chemosensation and genetic individuality

Numerous studies have shown that there are measurable behavioural consequences that can result from the olfactory recognition of alleles borne at the major histocompatibility complex (MHC). These consequences include simple individual recognition, disassortative mate preference, discrimination of kin from non-kin and whether a pregnancy is carried to term. Such a system, which can influence the reproductive behaviour of a species, will have profound effects on its genetic constitution and survival. The likely mechanism responsible for the production of MHC-related odours involves soluble MHC molecules that carry allele-specific odoriferous molecules from the blood via the kidneys into the urine, from where they are released into the environment. The ability of soluble MHC molecules to signal genetic individuality in this way may have evolved before the appearance of an acquired immune system in our immediate ancestors, the protochordates.

Dynamic associations of heterochromatin protein 1 with the nuclear envelope

To study the dynamics of mammalian HP1 proteins we have microinjected recombinant forms of mHP1alpha, M31 and M32 into the cytoplasm of living cells. As could be expected from previous studies, the three fusion proteins were efficiently transported into the nucleus and targeted specific chromatin areas. However, before incorporation into these areas the exogenous proteins accumulated in a peripheral zone and associated closely with the nuclear envelope. This transient association did not occur when the cells were treated with deacetylase inhibitors, indicating an acetylation-inhibited interaction. In line with these observations, recombinant HP1 proteins exhibited saturable binding to purified nuclear envelopes and stained the nuclei of detergent-permeabilized cells in a rim-like fashion. Competition experiments with various M31 mutants allowed mapping of the nuclear envelope-binding site within an N-terminal region that includes the chromodomain. A His(6)-tagged peptide representing this region inhibited recruitment of LAP2beta and B-type lamins around the surfaces of condensed chromosomes, suggesting involvement of HP1 proteins in nuclear envelope reassembly.

Conservation of heterochromatin protein 1 function

Heterochromatin represents a cytologically visible state of heritable gene repression. In the yeast, Schizosaccharomyces pombe, the swi6 gene encodes a heterochromatin protein 1 (HP1)-like chromodomain protein that localizes to heterochromatin domains, including the centromeres, telomeres, and the donor mating-type loci, and is involved in silencing at these loci. We identify here the functional domains of swi6p and demonstrate that the chromodomain from a mammalian HP1-like protein, M31, can functionally replace that of swi6p, showing that chromodomain function is conserved from yeasts to humans. Site-directed mutagenesis, based on a modeled three-dimensional structure of the swi6p chromodomain, shows that the hydrophobic amino acids which lie in the core of the structure are critical for biological function. Gel filtration, gel overlay experiments, and mass spectroscopy show that HP1 proteins can self-associate, and we suggest that it is as oligomers that HP1 proteins are incorporated into heterochromatin complexes that silence gene activity.

Chromatin complexes as aperiodic microcrystalline arrays that regulate genome organisation and expression

The current understanding of chromatin-mediated repression in Metazoa stems largely from work on two systems in Drosophila: heterochromatin-induced position-effect variegation and repression of the homeotic genes by the Polycomb-group of genes. A common feature of these two systems is the cooperative assembly of multimeric complexes which can epigenetically silence gene activity. Moreover, both older and more recent work has suggested that these complexes can themselves associate to give rise to larger complexes: The specificity of the association is likely to be determined by complementarity of the structural components of the complexes. Here, we aim to accommodate these, and other, features of chromatin-mediated repression in a single hypothesis, namely the crystallisation hypothesis. This hypothesis views the nucleus as being an environment that favours the formation of chromatin complexes which behave as aperiodic microcrystalline arrays constructed through the cooperative assembly of different types of lattice unit. The lattice units possess regions of structural complementarity that allow interactions between complexes. Aperiodicity confers specificity on the complexes and is a key feature of the model which, we suggest, provides a gene with a "chromosomal address." The chromosomal address allows the side-by-side alignment of homologous chromosomal regions, a properly that may be important in a variety of biologically relevant situations. Aperiodicity is also a feature of the hypothesis that is directly testable.

Mammalian chromodomain proteins: their role in genome organisation and expression

The chromodomain is a highly conserved sequence motif that has been identified in a variety of animal and plant species. In mammals, chromodomain proteins appear to be either structural components of large macromolecular chromatin complexes or proteins involved in remodelling chromatin structure. Recent work has suggested that apart from a role in regulating gene activity, chromodomain proteins may also play roles in genome organisation. This article reviews progress made in characterising mammalian chromodomain proteins and emphasises their emerging role in the regulation of gene expression and genome organisation. BioEssays 22:124-137, 2000.

Mammalian chromodomain proteins: their role in genome organisation and expression

The chromodomain is a highly conserved sequence motif that has been identified in a variety of animal and plant species. In mammals, chromodomain proteins appear to be either structural components of large macromolecular chromatin complexes or proteins involved in remodelling chromatin structure. Recent work has suggested that apart from a role in regulating gene activity, chromodomain proteins may also play roles in genome organisation. This article reviews progress made in characterising mammalian chromodomain proteins and emphasises their emerging role in the regulation of gene expression and genome organisation. BioEssays 22:124-137, 2000.

Embryonic inheritance of the chromatin organisation of the imprinted H19 domain in mouse spermatozoa

Insulin-like growth factor 2 (Igf 2) and H19 genes are oppositely imprinted and as such have been most extensively studied imprinted genes both genetically and at the molecular level. Imprints of the H19 gene, being established during spermatogenesis, are epigenetically transmitted to the somatic cells of the embryo. Current hypotheses attempting to explain the allele-specific silence of the H19 gene include DNA methylation and chromatin condensation. In order to understand the molecular basis of H19 epigenesis, it is crucial to identify the markings in the chromatin organising the imprinted domain in spermatozoa. Using Micrococcal nuclease (MNase), DNase I and Methidiumpropyl-EDTA. iron II (MPE.Fe(II)) as chromatin probes, we demonstrate that in mouse epididymal spermatozoa, at least 4kb DNA upstream of the H19 'cap' site, containing the imprinted and differentially methylated domain (DMD), is heterochromatic. The cleavage sites in this domain (-2 to -4kb) exhibit approximately 425bp periodicity. This structure is maintained in the paternal allele of normal embryos and is disrupted at -2.2, -2.65 and at -3.5kb in embryos maternally disomic for the distal end of chromosome 7 (MatDp 7). The hypersensitive sites in chromatin precisely register the MPE.Fe(II) cleavage sites in chromosomal DNA. Therefore, the DNA sequences in the imprinted domain constrain the chromatin structure in a way similar to that of 1.688g/cm(3) Drosophila satellite chromatin. In addition, we find that condensation of the paternal allele correlates with methylation-dependent alteration in the structure of DNA sequences in DMD. These results suggest that CpG-methylation induces localised changes in DNA conformation and these facilitate consequent remodelling of chromatin thereby allowing the paternal and maternal H19 alleles to be distinguished.

The murine heterochromatin protein M31 is associated with the chromocenter in round spermatids and Is a component of mature spermatozoa

In mature sperm the normal nucleosomal packaging of DNA found in somatic and meiotic cells is transformed into a highly condensed form of chromatin which consists mostly of nucleoprotamines. Although sperm DNA is highly condensed it is nevertheless packaged into a highly defined nuclear architecture which may be organized by the heterochromatic chromocenter. One major component of heterochromatin is the heterochromatin protein 1 which is involved in epigenetic gene silencing. In order to investigate the possible involvement of heterochromatin protein in higher order organization of sperm DNA we studied the localization of the murine homologue of heterochromatin protein 1, M31, during chromatin reorganization in male germ cell differentiation. Each cell type in the testis showed a unique distribution pattern of M31. Colocalization to the heterochromatic regions were found in Sertoli cells, in midstage pachytene spermatocytes, and in round spermatids in which M31 localizes to the centromeric chromocenter. M31 cannot be detected in elongated spermatids or mature spermatozoa immunocytologically, but could be detected in mature spermatozoa by Western blotting. We suggest that M31, a nuclear protein involved in the organization of chromatin architecture, is involved in higher order organization of sperm DNA.

M31, a murine homolog of Drosophila HP1, is concentrated in the XY body during spermatogenesis

The formation of the sex vesicle, or XY body, during male meiosis and pairing of the sex chromosomes are thought to be essential for successful spermatogenesis. Despite its cytological discovery a century ago, the mechanism of XY body formation, particularly heterochromatinization of the sex chromosomes, has remained unclear. The HP1 class of chromobox genes are thought to encode proteins involved in the packaging of chromosomal DNA into repressive heterochromatin domains, as seen, for example, in position-effect variegation. Study of the distribution of a murine HP1-like chromodomain protein, M31, during spermatogenesis revealed spreading from the tip of the XY body in mid-stage pachytene spermatocytes to include the whole of the XY body in late-pachytene spermatocytes. We also demonstrate that the formation of the XY body during spermatogenic progression in neonatal mice coincides with the expression of a novel nuclear isoform of M31, M31(p21). These results support the view that a common mechanistic basis exists for heterochromatin-induced repression, homeotic gene silencing, and sex-chromosome inactivation during mammalian spermatogenesis.

The present status of the 'carrier hypothesis' for chemosensory recognition of genetic individuality

The hypothesis that soluble MHC Class I molecules could act as the vector which transports MHC-specific odours from the blood into the urine was put forward some ten years ago (Singh, Brown & Roser, 1987). Here, I summarise new evidence in favour of the hypothesis. 'We propose that the ability of MHC Class I molecules to associate in a selective way with other small molecules could also be the mechanism by which a unique mixture of volatile, endogenous metabolites is transported by [soluble] class I MHC glycoproteins from the blood into the urine' (Singh, Brown & Roser, 1987).

KAP-1 corepressor protein interacts and colocalizes with heterochromatic and euchromatic HP1 proteins: a potential role for Krüppel-associated box-zinc finger proteins in heterochromatin-mediated gene silencing

Krüppel-associated box (KRAB) domains are present in approximately one-third of all human zinc finger proteins (ZFPs) and are potent transcriptional repression modules. We have previously cloned a corepressor for the KRAB domain, KAP-1, which is required for KRAB-mediated repression in vivo. To characterize the repression mechanism utilized by KAP-1, we have analyzed the ability of KAP-1 to interact with murine (M31 and M32) and human (HP1alpha and HP1gamma) homologues of the HP1 protein family, a class of nonhistone heterochromatin-associated proteins with a well-established epigenetic gene silencing function in Drosophila. In vitro studies confirmed that KAP-1 is capable of directly interacting with M31 and hHP1alpha, which are normally found in centromeric heterochromatin, as well as M32 and hHP1gamma, both of which are found in euchromatin. Mapping of the region in KAP-1 required for HP1 interaction showed that amino acid substitutions which abolish HP1 binding in vitro reduce KAP-1 mediated repression in vivo. We observed colocalization of KAP-1 with M31 and M32 in interphase nuclei, lending support to the biochemical evidence that M31 and M32 directly interact with KAP-1. The colocalization of KAP-1 with M31 is sometimes found in subnuclear territories of potential pericentromeric heterochromatin, whereas colocalization of KAP-1 and M32 occurs in punctate euchromatic domains throughout the nucleus. This work suggests a mechanism for the recruitment of HP1-like gene products by the KRAB-ZFP-KAP-1 complex to specific loci within the genome through formation of heterochromatin-like complexes that silence gene activity. We speculate that gene-specific repression may be a consequence of the formation of such complexes, ultimately leading to silenced genes in newly formed heterochromatic chromosomal environments.

Functional mammalian homologues of the Drosophila PEV-modifier Su(var)3-9 encode centromere-associated proteins which complex with the heterochromatin component M31

The chromo and SET domains are conserved sequence motifs present in chromosomal proteins that function in epigenetic control of gene expression, presumably by modulating higher order chromatin. Based on sequence information from the SET domain, we have isolated human (SUV39H1) and mouse (Suv39h1) homologues of the dominant Drosophila modifier of position-effect-variegation (PEV) Su(var)3-9. Mammalian homologues contain, in addition to the SET domain, the characteristic chromo domain, a combination that is also preserved in the Schizosaccharyomyces pombe silencing factor clr4. Chromatin-dependent gene regulation is demonstrated by the potential of human SUV39H1 to increase repression of the pericentromeric white marker gene in transgenic flies. Immunodetection of endogenous Suv39h1/SUV39H1 proteins in a variety of mammalian cell lines reveals enriched distribution at heterochromatic foci during interphase and centromere-specific localization during metaphase. In addition, Suv39h1/SUV39H1 proteins associate with M31, currently the only other characterized mammalian SU(VAR) homologue. These data indicate the existence of a mammalian SU(VAR) complex and define Suv39h1/SUV39H1 as novel components of mammalian higher order chromatin.

The fission yeast chromo domain encoding gene chp1(+) is required for chromosome segregation and shows a genetic interaction with alpha-tubulin

In eukaryotes, the segregation of chromosomes is co-ordinated by the centromere and must proceed accurately if aneuploidy and cell death are to be avoided. The fission yeast centromere is complex, containing highly repetitive regions of DNA showing the characteristics of heterochromatin. Two proteins, Swi6p and Clr4p, that are associated with the fission yeast centromere also contain a chromo (chromatin organisation modifier) domain and are required for centromere function. We have analysed a novel fission yeast gene encoding a putative chromo domain called chp 1(+) (chromo domain protein in Schizosaccharomyces p ombe ). In the absence of Chp1p protein, cells are viable but show chromosome segregation defects such as lagging chromosomes on the spindle during anaphase and high rates of minichromosome loss, phenotypes which are also displayed by swi 6 and clr 4. A fusion protein between green fluorescent protein (GFP) and Chp1p, like Swi6p, is localized to discrete sites within the nucleus. In contrast to Swi6p and Clr4p, Chp1p is not required to repress silent mating-type genes. We demonstrate a genetic interaction between chp 1(+) and alpha-tubulin ( nda 2(+)) and between swi 6(+) and beta-tubulin ( nda 3(+)). Chp1p and Swi6p proteins may be components of the kinetochore which captures and stabilizes the microtubules of the spindle.