Multiple display of a protein domain on a bacterial polymeric scaffold

The multiple display of protein domains on polymeric scaffolds is an emerging technology for many applications. BLS is a highly immunogenic protein that has an oligomeric structure formed by a 17.2 kDa subunit arranged as a dimer of pentamers. Here we describe the production as well as the structural, functional, and immunological properties of a 9 kDa double-stranded RNA-binding domain (RBD3) fused to the structure of BLS. We demonstrate that the BLS and RBD3 modules are stably and independently folded in the structure of the chimera and form a decameric structure of 255 kDa as the native BLS oligomers. The polymeric display of RBD3 in the structure of BLS increases the dsRNA binding strength of this domain both in vitro and in vivo, and also enhances its immunogenicity to the point that it breaks the tolerance of mice to the RBD3 self-antigen. Our results underscore the BLS display strategy as a powerful tool for biotechnological and therapeutic applications.

Evaluating bacterial pathogen DNA preservation in museum osteological collections

Reports of bacterial pathogen DNA sequences obtained from archaeological bone specimens raise the possibility of greatly improving our understanding of the history of infectious diseases. However, the survival of pathogen DNA over long time periods is poorly characterized, and scepticism remains about the reliability of these data. In order to explore the survival of bacterial pathogen DNA in bone specimens, we analysed samples from 59 eighteenth and twentieth century individuals known to have been infected with either Mycobacterium tuberculosis or Treponema pallidum. No reproducible evidence of surviving pathogen DNA was obtained, despite the use of extraction and PCR-amplification methods determined to be highly sensitive. These data suggest that previous studies need to be interpreted with caution, and we propose that a much greater emphasis is placed on understanding how pathogen DNA survives in archaeological material, and how its presence can be properly verified and used.

The routine use of intra-operative ultrasound in patients with colorectal cancer improves the detection of hepatic metastases

INTRODUCTION

Up to one fifth of patients with carcinoma of the colon have occult liver metastases at the time of presentation. Intra-operative hepatic ultrasonography might improve disease staging. We report the use of intra-operative ultrasonography (IOUS) in routine clinical practice over a five-year period.

METHOD

Seventy-six patients with colorectal carcinoma (F 21, M 55) of median age 67 years (range 43-89 years) for whom full data were available had IOUS at the time of colonic resection. All patients had had a computerized tomography (CT), magnetic resonance imaging (MRI) or ultrasonography (USS).

RESULTS

Of 76 patients, 10 had a Dukes A, 32 had a Dukes B and 34 a Dukes C carcinoma. In 20 patients IOUS detected lesions not seen on pre-operative scanning including 11 metastases (one suitable for resection), seven benign hepatic cysts and two were benign hepatic nodules. Forty-nine patients have remained free of disease and 25 have died with systemic disease (mean survival 10 months, range 2-24 months). In the seven patients diagnosed as having hepatic cysts at IOUS two have died of systemic disease. The remaining patients (n=12) who died with systemic disease had a negative IOUS.

CONCLUSION

IOUS increases diagnostic yield but a significant proportion of patients with occult hepatic metastases are not detected. IOUS improves disease staging in some patients refining the indications for adjuvant therapy and enhancing the estimate of prognosis and improving decision-making.

Pulmonary staging in colorectal cancer--is computerised tomography the answer?

INTRODUCTION

Pulmonary staging in colorectal cancer (CRC) has traditionally been carried out by means of plain chest radiograph (CXR), although computerised tomography (CT) imaging of the chest is increasingly being performed for this purpose. The aim of this study was to assess the value of pre-operative thoracic CT for pulmonary staging in CRC.

PATIENTS AND METHODS

Data were collected prospectively on all patients referred into hospital over a 20-month study period for double contrast barium enema evaluation of symptoms suggestive of an underlying CRC. Patients with a CRC went on to have a staging intravenous, contrast-enhanced CT of the chest, abdomen and pelvis prior to an out-patient appointment with a colorectal surgeon. The CXRs of those patients in whom a radiological abnormality was seen on thoracic CT were reviewed blindly by an independent consultant radiologist.

RESULTS

A total of 403 barium enemas were performed, of which 38 demonstrated a CRC (9%). In those patients diagnosed with CRC, nine (24%) had an abnormality on thoracic CT. Four patients with positive thoracic CTs had chemotherapy and or radiotherapy with no surgery. One patient underwent colectomy, and 2 patients who had primary lung tumours as opposed to metastases also underwent colectomies. One patient received palliative care only. In addition, one of the patients underwent multiple, non-diagnostic thoracic investigations prior to a diagnosis of sarcoidosis being made and then proceeding to surgery. An independent consultant radiologist reviewed seven out of the nine CXRs of patients with an abnormality on thoracic CT without knowledge of the clinical diagnosis, and reported three of the CXRs to be normal.

CONCLUSIONS

Thoracic CT appears to improve the accuracy of pulmonary staging in CRC allowing a more appropriate level of intervention. However, CT is likely to identify more benign radiological abnormalities than CXR alone, and investigations should not occur to the detriment of treating the primary tumour.

Single-fiber electromyography correlates more closely with incontinence scores than pudendal nerve terminal motor latency

BACKGROUND

The investigation of fecal incontinence is important in deciding the most appropriate treatment. The presence of neuropathy has been shown to affect surgical outcomes adversely. Latency studies are of dubious value in assessing neuropathy; needle electromyography is the gold standard test. The relationship between these two tests and the symptoms of fecal incontinence has not been studied.

METHOD

A cohort of 57 patients underwent neurologic and symptom assessment using latency studies, concentric and single-fiber electromyography, and symptom assessment using the Cleveland Clinic Scoring System.

RESULTS

There was a significant correlation between left mean fiber density and Cleveland Clinic Scoring (correlation: 0.32, P = 0.02) but not between right or left latency studies.

CONCLUSION

Single-fiber electromyography gave relevant results that could be obtained easily on modern equipment. Latency values were not reliable.

The phylogenetic position of the ‘giant deer’ Megaloceros giganteus

The giant deer, or 'Irish elk', has featured extensively in debates on adaptation, sexual selection, and extinction. Its huge antlers--the largest of any deer species, living or extinct--formed a focus of much past work. Yet the phylogenetic position of the giant deer has remained an enigma. On the basis of its flattened antlers, the species was previously regarded as closely related to the living fallow deer. Recent morphological studies, however, have challenged that view and placed the giant deer closer to the living red deer or wapiti. Here we present a new phylogenetic analysis encompassing morphological and DNA sequence evidence, and find that both sets of data independently support a sister-group relationship of giant and fallow deer. Our results include the successful extraction and sequencing of DNA from this extinct species, and highlight the value of a joint molecular and morphological approach.

Cannula-associated Staphylococcus aureus bacteraemia: outcome in relation to treatment

BACKGROUND

Despite the frequency of cannula-associated Staphylococcus aureus bacteraemia (CASAB) there is uncertainty regarding the duration of treatment required.

AIM

To determine the relationship between the duration and type of treatment for CASAB and subsequent relapse with deep-seated S. aureus infection.

METHODS

We prospectively studied 276 patients with CASAB. Patients were followed for at least 8 weeks after completion of antibiotic treatment. Initial and subsequent isolates of S. aureus were compared using molecular methods to determine strain similarity.

RESULTS

Initial mortality was 9% (26 of 276) and a complicating focus of infection presented during initial treatment in 6% (15 of 250) of the survivors. There were nine relapses of deep-seated infection from the strain causing the original infection. Relapses were equally common following peripheral CASAB and central CASAB. There was no relationship between the duration of treatment and the rate of relapse of deep-seated infection (P = 0.24). This observation held true regardless of whether the duration of treatment was analysed as < or = 7 versus > or = 8, < or =10 versus > or =11, or < or=14 versus > or =15 days (P = 0.62, 0.87 and 0.16, respectively).

CONCLUSION

Episodes of peripheral CASAB pose an equal risk of relapse to central cannula-related episodes. Although further studies are needed to determine the optimal treatment of CASAB, our study strongly suggests that more than 14 days treatment is excessive for most patients who respond promptly to cannula removal and antibiotic treatment.

Fast-track barium enema: meeting the two-week wait rule for patients with suspected colorectal cancer

OBJECTIVES

To meet the introduction of the two-week wait (TWW) rule for patients with suspected colorectal cancer, a fast-track barium enema (FTBE) service was set up. This study was conducted to evaluate the success of this approach in preparation for meeting the forthcoming targets on waiting times to treatment from referral and diagnosis.

METHODS

All patients were offered a double-contrast barium enema within two-weeks, except those with a palpable rectal mass. FTBE were double-reported by specialist gastrointestinal radiologists. Patients with a suspected malignancy were booked for an urgent staging CT and outpatient appointment, whilst the remaining patients were referred back to their general practitioner with a report. Prospective data were collected and two 16-month periods analysed.

RESULTS

Three hundred and nine patients had a FTBE over the first 16-month period and 277 (89.6%) were seen within two-weeks. Mean times from initial referral to staging CT and first outpatient appointment were 30.7 and 36.0 days, respectively. Cancer was confirmed histologically in 32 (10.4%) patients. Of 267 patients without a malignancy, 46 (17.2%) were referred back to the colorectal outpatient or endoscopy service within 6-months. The number of referrals increased with time from a mean of 19.3 per month in the first period to 27.8 in the second, but the percentage with a suspected malignancy remained similar at 13.6% and 10.1%, respectively.

CONCLUSION

FTBE diagnosed malignancy accurately and facilitated rapid staging. The TWW target was met in almost 90% of patients, whilst the impact on the colorectal outpatient and endoscopy service was minimized.

The role of colonoscopic endoanal ultrasound scanning (EUS) in selecting patients suitable for resection by transanal endoscopic microsurgery (TEM)

OBJECTIVE

This study was performed to assess the accuracy of colonoscopic endoanal ultrasound scanning (EUS) in the selection of patients with rectal neoplasia suitable for local excision by transanal endoscopic microsurgery (TEM). Our policy is to offer TEM to patients with premalignant (T0) lesions or with T1 tumours that have early disease.

PATIENTS AND METHODS

Data were collected prospectively on all patients undergoing EUS for the assessment of rectal neoplasia at our institution over a six-year period. A colonoscopic EUS probe was used to determine whether the tumour breached the muscularis propria (the interface between T1 and T2 disease). Subsequently patients underwent surgical resection, including TEM for those with T0/1 disease. The preoperative stage predicted by EUS (uT stage) was compared to the postoperative histopathological stage of the resected specimens (pT stage).

RESULTS

One hundred and fifty-six EUS examinations were evaluated. Sixty-two patients went on to have TEM whilst the remaining 94 had another form of surgery. Of the 62 patients undergoing TEM, 3 were overstaged on EUS. No patients were understaged, giving an accuracy of 95%. Of the 94 patients undergoing an alternative procedure, 5 were overstaged on EUS as having T2 tumours when in fact their histology was T1. Accuracy of EUS at predicting more advanced disease fell to 89%, giving an overall accuracy of 92%.

CONCLUSIONS

EUS is accurate at predicting T0/1 vs T2 disease in our institution, and we believe that it is a useful modality in assessing patient suitability for local excision.

Diet and the frequency of the alanine:glyoxylate aminotransferase Pro11Leu polymorphism in different human populations

The intermediary metabolic enzyme alanine:glyoxylate aminotransferase (AGT) contains a Pro11Leu polymorphism that decreases its catalytic activity by a factor of three and causes a small proportion to be mistargeted from its normal intracellular location in the peroxisomes to the mitochondria. These changes are predicted to have significant effects on the synthesis and excretion of the metabolic end-product oxalate and the deposition of insoluble calcium oxalate in the kidney and urinary tract. Based on the evolution of AGT targeting in mammals, we have previously hypothesised that this polymorphism would be advantageous for individuals who have a meat-rich diet, but disadvantageous for those who do not. If true, the frequency distribution of Pro11Leu in different extant human populations should have been shaped by their dietary history so that it should be more common in populations with predominantly meat-eating ancestral diets than it is in populations in which the ancestral diets were predominantly vegetarian. In the present study, we have determined frequency of Pro11Leu in 11 different human populations with divergent ancestral dietary lifestyles. We show that the Pro11Leu allelic frequency varies widely from 27.9% in the Saami, a population with a very meat-rich ancestral diet, to 2.3% in Chinese, who are likely to have had a more mixed ancestral diet. FST analysis shows that the differences in Pro11Leu frequency between some populations (particularly Saami vs Chinese) was very high when compared with neutral loci, suggesting that its frequency might have been shaped by dietary selection pressure.

Living with HIV in New Zealand: balancing health and quality of life

AIM

This paper characterises the health and wellbeing of HIV-positive people in New Zealand.

METHODS

The HIV Futures New Zealand Survey is a self-complete anonymous questionnaire distributed in a variety of ways. Data were collected on health, clinical, and social variables.

RESULTS

There were 226 responses, estimated to be approximately 25% of the HIV positive population. Respondents were aged between 18 and 68, and 56% were homosexual men. Most (68%) reported a viral load on most recent test of below 500 copies/mL and 59% had a CD4 lymphocyte count on most recent test of over 250 cells/mcL. However, 28% reported a major health condition in addition to HIV and 21% had a mental health condition. Most respondents (64%) were currently using antiretroviral therapy. Many (84%) knew other people with HIV and had contact with an HIV/AIDS organisation (77%). Forty-two percent of respondents had stopped working because of HIV, and 47% reported their main source of income as a Government benefit.

CONCLUSIONS

This research has demonstrated that, while the HIV-positive population of New Zealand generally has improved health as a result of antiretroviral therapy, there are still significant social and economic barriers to their quality of life.

An analysis of consanguinity and social structure within the UK Asian population using microsatellite data

We analysed microsatellite genotypes sampled from the Pakistani and Indian communities in Nottingham, UK, to investigate the genetic consequences of substructuring mediated by traditional marriage customs. The application of a recently developed likelihood approach identified significant levels of population substructure within the Pakistani community as a whole, as well as within the finer divisions of castes and biradheri. In addition, high levels of cryptic or unacknowledged consanguinity were detected within subgroups of this community, including biradheri. The Indian sample showed no significant evidence of either substructure or consanguinity. We demonstrate that estimates of disease gene frequencies can be inaccurate unless they are made jointly with estimates of population substructure and consanguinity ((theta congruent to FST) and C). The magnitude of these estimates also highlights the importance of accounting for the finer scale of social structuring when making decisions regarding the risk of recessive disorders in offspring.

The T allele of a single-nucleotide polymorphism 13.9 kb upstream of the lactase gene (LCT) (C-13.9kbT) does not predict or cause the lactase-persistence phenotype in Africans

The ability to digest the milk sugar lactose as an adult (lactase persistence) is a variable genetic trait in human populations. The lactase-persistence phenotype is found at low frequencies in the majority of populations in sub-Saharan Africa that have been tested, but, in some populations, particularly pastoral groups, it is significantly more frequent. Recently, a CT polymorphism located 13.9 kb upstream of exon 1 of the lactase gene (LCT) was shown in a Finnish population to be closely associated with the lactase-persistence phenotype (Enattah et al. 2002). We typed this polymorphism in 1,671 individuals from 20 distinct cultural groups in seven African countries. It was possible to match seven of the groups tested with groups from the literature for whom phenotypic information is available. In five of these groups, the published frequencies of lactase persistence are >/=25%. We found the T allele to be so rare that it cannot explain the frequency of the lactase-persistence phenotype throughout Africa. By use of a statistical procedure to take phenotyping and sampling errors into account, the T-allele frequency was shown to be significantly different from that predicted in five of the African groups. Only the Fulbe and Hausa from Cameroon possessed the T allele at a level consistent with phenotypic observations (as well as an Irish sample used for comparison). We conclude that the C-13.9kbT polymorphism is not a predictor of lactase persistence in sub-Saharan Africans. We also present Y-chromosome data that are consistent with previously reported evidence for a back-migration event into Cameroon, and we comment on the implications for the introgression of the -13.9kb*T allele.

Cushing's syndrome due to interaction between inhaled corticosteroids and itraconazole

OBJECTIVE

To report a case of an interaction between inhaled corticosteroids and itraconazole causing iatrogenic Cushing's syndrome and provide a review of the relevant literature.

CASE SUMMARY

A 70-year-old white woman on long-term treatment with high-dose inhaled corticosteroids for asthma was diagnosed as having Scedosporium apiospermum infection of the skin and subcutaneous tissues. As a result, she was treated with itraconazole for 2 months. She subsequently developed Cushing's syndrome due to a probable cytochrome P450-mediated interaction between itraconazole and budesonide. She also had secondary adrenal insufficiency requiring prolonged treatment with replacement hydrocortisone.

DISCUSSION

Budesonide is a potent glucocorticoid that is metabolized in the liver by the CYP3A4 isoenzyme to inactive metabolites. Itraconazole is a potent cytochrome P450 inhibitor. It can inhibit the metabolism of oral or inhaled corticosteroids, producing cortisol excess leading to Cushing's syndrome and adrenal insufficiency. An assessment of causality indicated a possible adverse interaction between itraconazole and budesonide.

CONCLUSIONS

The combination of itraconazole and inhaled corticosteroids is increasingly being used to treat conditions such as allergic bronchopulmonary aspergillosis. Clinicians need to be aware of the potential for an interaction between such a combination.

Effect of written emotional expression on immune function in patients with human immunodeficiency virus infection: a randomized trial

OBJECTIVES

To determine whether writing about emotional topics compared with writing about neutral topics could affect CD4+ lymphocyte count and human immunodeficiency virus (HIV) viral load among HIV-infected patients.

METHODS

Thirty-seven HIV-infected patients were randomly allocated to 2 writing conditions focusing on emotional or control topics. Participants wrote for 4 days, 30 minutes per day. The CD4+ lymphocyte count and HIV viral load were measured at baseline and at 2 weeks, 3 months, and 6 months after writing.

RESULTS

The emotional writing participants rated their essays as more personal, valuable, and emotional than those in the control condition. Relative to the drop in HIV viral load, CD4+ lymphocyte counts increased after the intervention for participants in the emotional writing condition compared with control writing participants.

CONCLUSIONS

The results are consistent with those of previous studies using emotional writing in other patient groups. Based on the self-reports of the value of writing and the preliminary laboratory findings, the results suggest that emotional writing may provide benefit for patients with HIV infection.

Effect of increasing levels of undegradable intake protein on metabolic and endocrine factors in estrous cycling beef heifers1,2

To determine the influence of three levels of undegradable intake protein (UIP) supplementation on metabolic and endocrine factors that influence reproduction, 23 yearling crossbred heifers (body condition score = 4.5 +/- 0.5; initial BW = 362 +/- 12 kg) were stratified by BW and assigned randomly to one of three supplements: 1) low UIP (1,135 g x heifer(-1) x d(-1); 30% CP, 115 g UIP, n = 7); 2) mid UIP (1,135 g x heifer(-1) x d(-1); 38% CP, 216 g UIP, n = 8); or 3) high UIP (1,135 g x heifer(-1) x d(-1); 46% CP, 321 g UIP, n = 8). Heifers were estrually synchronized before initiation of supplementation. Supplement was individually fed daily for 30 to 32 d, at which time heifers were slaughtered (d 12 to 14 of the estrous cycle) and tissues collected. Heifers were fed a basal diet of sudan grass hay (6.0% CP) ad libitum. On d 28 of supplementation (d 10 of the estrous cycle), no differences were observed (P > 0.10) in serum insulin or IGF-I among treatments. At slaughter (d 10 to 12 of the estrous cycle), treatments did not influence corpus luteum weight, cerebral spinal fluid leptin, or IGFBP; serum estradiol-17beta, progesterone, leptin, IGF-I, and IGFBP; or anterior pituitary content of IGFBP (P > 0.10). Follicular fluid IGFBP-2 and IGFBP-4 were greater in high-UIP heifers than low- or mid-UIP heifers on d 12 to 14 of the estrous cycle (P < 0.05). Basal serum LH concentrations and LH area under the curve (every 15 min for 240 min) did not differ (P > 0.10) following 28 d of supplementation (d 10 of the estrous cycle); however, basal serum FSH concentrations were greater (P = 0.06) in low- and mid- vs. high-UIP heifers (5.2 and 5.2 vs. 4.6 ng/mL, respectively), and FSH area under the curve was greater (P = 0.03) in low- vs. high-UIP heifers. At slaughter (d 12 to 14 of the estrous cycle), anterior pituitary LH and FSH content and steady-state mRNA encoding alpha, LHbeta, and GnRH receptor did not differ (P > 0.10) among treatments. However, FSHbeta mRNA was increased approximately twofold (P = 0.03) in mid vs. low UIP. In summary, low and mid levels of UIP supplements fed to estrous cycling beef heifers seemed to enhance pituitary expression and/or secretion of FSH relative to high levels of UIP. Moreover, high-UIP supplementation was associated with increased low-molecular-weight IGFBP compared with supplementation of low and mid levels of UIP. These data suggest that differing levels of UIP supplementation may alter pituitary and ovarian function, thereby influencing reproductive performance in beef heifers.

Multiple origins of Ashkenazi Levites: Y chromosome evidence for both Near Eastern and European ancestries

Previous Y chromosome studies have shown that the Cohanim, a paternally inherited Jewish priestly caste, predominantly share a recent common ancestry irrespective of the geographically defined post-Diaspora community to which they belong, a finding consistent with common Jewish origins in the Near East. In contrast, the Levites, another paternally inherited Jewish caste, display evidence for multiple recent origins, with Ashkenazi Levites having a high frequency of a distinctive, non-Near Eastern haplogroup. Here, we show that the Ashkenazi Levite microsatellite haplotypes within this haplogroup are extremely tightly clustered, with an inferred common ancestor within the past 2,000 years. Comparisons with other Jewish and non-Jewish groups suggest that a founding event, probably involving one or very few European men occurring at a time close to the initial formation and settlement of the Ashkenazi community, is the most likely explanation for the presence of this distinctive haplogroup found today in >50% of Ashkenazi Levites.

Effect of neuropeptide Y on GnRH-induced LH release from bovine anterior pituitary cell cultures derived from heifers in a follicular, luteal or ovariectomized state

Objectives were to determine if neuropeptide Y (NPY) had direct effects GnRH induced secretion of LH from the anterior pituitary gland, and if endogenous steroids modulated the effect of NPY. To accomplish these objectives, 15 Hereford heifers were assigned to one of three ovarian status groups: follicular, luteal, or ovariectomized. One animal from each of the three ovarian status groups was slaughtered on each of 5 days and anterior pituitary gland harvested. Anterior pituitary gland cells within ovarian status were equally distributed and randomly assigned to one of three cell culture treatments: no NPY or GnRH (control), 10 nM GnRH, or 100 nM NPY+10 nM GnRH. Anterior pituitary cell cultures were incubated with or without NPY for 4 h and further incubated for an additional 2 h with or without GnRH and supernatant collected for quantification of LH. Treatment of anterior pituitary cell cultures with GnRH or GnRH+NPY did not affect LH release in cultures obtained from follicular (S.E.=5%; P=0.58) or ovariectomized (S.E.=7%; P=0.22) heifers. Both GnRH and GnRH+NPY increased LH release from anterior pituitary cell cultures from heifers in the luteal phase (S.E.=14%; P < or = 0.05) compared to control cultures. Cultures from luteal phase heifers treated with GnRH did not differ from those treated with GnRH+NPY (P=0.34). These data provide evidence to suggest that effects of NPY on LH release may occur primarily at the level of the hypothalamus.

Y-chromosome evidence for differing ancient demographic histories in the Americas

To scrutinize the male ancestry of extant Native American populations, we examined eight biallelic and six microsatellite polymorphisms from the nonrecombining portion of the Y chromosome, in 438 individuals from 24 Native American populations (1 Na Dené and 23 South Amerinds) and in 404 Mongolians. One of the biallelic markers typed is a recently identified mutation (M242) characterizing a novel founder Native American haplogroup. The distribution, relatedness, and diversity of Y lineages in Native Americans indicate a differentiated male ancestry for populations from North and South America, strongly supporting a diverse demographic history for populations from these areas. These data are consistent with the occurrence of two major male migrations from southern/central Siberia to the Americas (with the second migration being restricted to North America) and a shared ancestry in central Asia for some of the initial migrants to Europe and the Americas. The microsatellite diversity and distribution of a Y lineage specific to South America (Q-M19) indicates that certain Amerind populations have been isolated since the initial colonization of the region, suggesting an early onset for tribalization of Native Americans. Age estimates based on Y-chromosome microsatellite diversity place the initial settlement of the American continent at approximately 14,000 years ago, in relative agreement with the age of well-established archaeological evidence.

Rare Deep-Rooting Y Chromosome Lineages in Humans: Lessons for Phylogeography

There has been considerable debate on the geographic origin of the human Y chromosome Alu polymorphism (YAP). Here we report a new, very rare deep-rooting haplogroup within the YAP clade, together with data on other deep-rooting YAP clades. The new haplogroup, found so far in only five Nigerians, is the least-derived YAP haplogroup according to currently known binary markers. However, because the interior branching order of the Y chromosome genealogical tree remains unknown, it is impossible to impute the origin of the YAP clade with certainty. We discuss the problems presented by rare deep-rooting lineages for Y chromosome phylogeography.

Role of the IGF-II receptor in mediating acute, non-genomic effects of retinoids and IGF-II on keratinocyte cell death

In this study, we have examined the effects of retinoic acid (RA) on the human immortalized keratinocyte cell line (HaCaT). A significant twofold (P < 0.01) increase in apoptotic cell death compared with the control was found within 24 h of treatment with 10-5 M of RA. Apoptosis was confirmed by flow cytometry. Cycloheximide did not inhibit this acute RA-induced apoptosis. Interestingly, insulin-like growth factor-II (IGF-II, 50 ng/ml) was able to significantly (67.3%; P < 0.05) reduce RA effects, whereas IGF-I (50 ng/ml) and insulin (75 ng/ml) were without effect. Furthermore, analogues of IGF-II [leu27 IGF-II and Des(1-6) IGF-II], with altered affinities for the IGF-I receptor and IGF-binding proteins (IGFBPs), but retained affinities for the IGF-II receptor, also completely inhibited (100%; P < 0.01) RA-induced apoptosis, while an IGF-I receptor antagonist did not reduce the survival effects of IGF-II. Insulin pretreatment negates the survival effect of IGF-II. In contrast, mannose 6 phosphate (M6P) did not alter RA or IGF-II actions. These results indicate that rapid induction of cell death by RA is independent of production or secretion of new proteins. The inhibition of RA action by IGF-II was independent of its ability to signal through the IGF-I receptor or to interact with IGFBPs.