Palaeoenvironments and hominin evolutionary dynamics in southeast Asia

Secure environmental contexts are crucial for hominin interpretation and comparison. The discovery of a Denisovan individual and associated fauna at Tam Ngu Hao 2 (Cobra) Cave, Laos, dating back to 164-131 ka, allows for environmental comparisons between this (sub)tropical site and the Palearctic Denisovan sites of Denisova Cave (Russia) and Baishiya Karst Cave (China). Denisovans from northern latitudes foraged in a mix of forested and open landscapes, including tundra and steppe. Using stable isotope values from the Cobra Cave assemblage, we demonstrate that, despite the presence of nearby canopy forests, the Denisovan individual from Cobra Cave primarily consumed plants and/or animals from open forests and savannah. Using faunal evidence and proxy indicators of climates, results herein highlight a local expansion of rainforest at ~ 130 ka, raising questions about how Denisovans responded to this local climate change. Comparing the diet and habitat of the archaic hominin from Cobra Cave with those of early Homo sapiens from Tam Pà Ling Cave (46-43 ka), Laos, it appears that only our species was able to exploit rainforest resources.

Early presence of Homo sapiens in Southeast Asia by 86-68 kyr at Tam Pà Ling, Northern Laos

The timing of the first arrival of Homo sapiens in East Asia from Africa and the degree to which they interbred with or replaced local archaic populations is controversial. Previous discoveries from Tam Pà Ling cave (Laos) identified H. sapiens in Southeast Asia by at least 46 kyr. We report on a recently discovered frontal bone (TPL 6) and tibial fragment (TPL 7) found in the deepest layers of TPL. Bayesian modeling of luminescence dating of sediments and U-series and combined U-series-ESR dating of mammalian teeth reveals a depositional sequence spanning ~86 kyr. TPL 6 confirms the presence of H. sapiens by 70 ± 3 kyr, and TPL 7 extends this range to 77 ± 9 kyr, supporting an early dispersal of H. sapiens into Southeast Asia. Geometric morphometric analyses of TPL 6 suggest descent from a gracile immigrant population rather than evolution from or admixture with local archaic populations.

Geographically diverse canid sampling provides novel insights into pre-industrial microbiomes

Canine microbiome studies are often limited in the geographic and temporal scope of samples studied. This results in a paucity of data on the canine microbiome around the world, especially in contexts where dogs may not be pets or human associated. Here, we present the shotgun sequences of fecal microbiomes of pet dogs from South Africa, shelter and stray dogs from India, and stray village dogs in Laos. We additionally performed a dietary experiment with dogs housed in a veterinary medical school, attempting to replicate the diet of the sampled dogs from Laos. We analyse the taxonomic diversity in these populations and identify the underlying functional redundancy of these microbiomes. Our results show that diet alone is not sufficient to recapitulate the higher diversity seen in the microbiome of dogs from Laos. Comparisons to previous studies and ancient dog fecal microbiomes highlight the need for greater population diversity in studies of canine microbiomes, as modern analogues can provide better comparisons to ancient microbiomes. We identify trends in microbial diversity and industrialization in dogs that mirror results of human studies, suggesting future research can make use of these companion animals as substitutes for humans in studying the effects of industrialization on the microbiome.

A multi-proxy approach to exploring Homo sapiens' arrival, environments and adaptations in Southeast Asia

The capability of Pleistocene hominins to successfully adapt to different types of tropical forested environments has long been debated. In order to investigate environmental changes in Southeast Asia during a critical period for the turnover of hominin species, we analysed palaeoenvironmental proxies from five late Middle to Late Pleistocene faunas. Human teeth discoveries have been reported at Duoi U'Oi, Vietnam (70-60 ka) and Nam Lot, Laos (86-72 ka). However, the use of palaeoproteomics allowed us to discard the latter, and, to date, no human remains older than ~ 70 ka are documented in the area. Our findings indicate that tropical rainforests were highly sensitive to climatic changes over that period, with significant fluctuations of the canopy forests. Locally, large-bodied faunas were resilient to these fluctuations until the cooling period of the Marine Isotope Stage 4 (MIS 4; 74-59 ka) that transformed the overall biotope. Then, under strong selective pressures, populations with new phenotypic characteristics emerged while some other species disappeared. We argue that this climate-driven shift offered new foraging opportunities for hominins in a novel rainforest environment and was most likely a key factor in the settlement and dispersal of our species during MIS 4 in SE Asia.

Pelvic Floor Dysfunction After Hysterectomy: Moving the Investigation Forward

The role of hysterectomy in the development of pelvic floor dysfunction (PFD) remains widely disputed. The controversy is fueled by two key factors. The first is conflicting association studies that make it difficult to establish whether a link truly exists. Although many retrospective studies report a correlation between hysterectomy and increased risk of stress urinary incontinence (SUI) or pelvic organ prolapse (POP), prospective studies often fail to replicate these results, leading some to conclude that no association exists. However, most prospective studies do not follow up for a sufficient length of time to account for the long latency of PFD and cannot unilaterally prove the absence of an association. The second source of controversy is the absence of a plausible mechanism to explain how hysterectomy could predispose patients to PFD. In this paper, we investigate autonomic innervation and smooth muscle in the three layers of pelvic floor support and propose a mechanism through which autonomic damage from hysterectomy could predispose patients to PFD. We then identify key research areas needed to evaluate this theory. This report aims to inspire a discussion on how to further the collective understanding of the relationship between hysterectomy and PFD. Clarifying the nature of this connection could have enormous consequences in redefining the risks and benefits of hysterectomy.

Use of Virtual Reality to Educate Undergraduate Medical Students on Cardiac Peripheral and Collateral Circulation

Many medical schools are looking to utilize virtual reality (VR); however, due to its novelty, we know little about how VR can be effectively used in medical education. This study evaluates a case-centered VR task that supported students with learning peripheral and collateral circulation, anatomical features that are not easily observed in cadavers. Data sources included a quiz, survey, and focus group. Based on quantitative and qualitative analyses, we support the claim that this activity was an effective use of VR and identify features that made it effective, which can guide other educators who are interested in developing VR activities.

Resistive exercise in astronauts on prolonged spaceflights provides partial protection against spaceflight-induced bone loss

Bone loss in astronauts during spaceflight may be a risk factor for osteoporosis, fractures and renal stone formation. We previously reported that the bisphosphonate alendronate, combined with exercise that included an Advanced Resistive Exercise Device (ARED), can prevent or attenuate group mean declines in areal bone mineral density (aBMD) measured soon after ~ 6-month spaceflights aboard the International Space Station (ISS). It is unclear however if the beneficial effects on postflight aBMD were due to individual or combined effects of alendronate and ARED. Hence, 10 additional ISS astronauts were recruited who used the ARED (ARED group) without drug administration using similar measurements in the previous study, i.e., densitometry, biochemical assays and analysis of finite element (FE) models. In addition densitometry data (DXA and QCT only) were compared to published data from crewmembers (n = 14-18) flown prior to in-flight access to the ARED (Pre-ARED). Group mean changes from preflight (± SD %) were used to evaluate effects of countermeasures as sequentially modified on the ISS (i.e., Pre-ARED vs. ARED; ARED vs. Bis+ARED). Spaceflight durations were not significantly different between groups. Postflight bone density measurements were significantly reduced from preflight in the Pre-ARED group. As previously reported, combined Bis+ARED prevented declines in all DXA and QCT hip densitometry and in estimates of FE hip strengths; increased the aBMD of lumbar spine; and prevented elevations in urinary markers for bone resorption during spaceflight. ARED without alendronate partially attenuated declines in bone mass but did not suppress biomarkers for bone resorption or prevent trabecular bone loss. Resistive exercise in the ARED group did not prevent declines in hip trabecular vBMD, but prevented reductions in cortical vBMD of the femoral neck, in FE estimate of hip strength for non-linear stance (NLS) and in aBMD of the femoral neck. We conclude that a bisphosphonate, when combined with resistive exercise, enhances the preservation of bone mass because of the added suppression of bone resorption in trabecular bone compartment not evident with ARED alone.

The prehistoric peopling of Southeast Asia

The human occupation history of Southeast Asia (SEA) remains heavily debated. Current evidence suggests that SEA was occupied by Hòabìnhian hunter-gatherers until ~4000 years ago, when farming economies developed and expanded, restricting foraging groups to remote habitats. Some argue that agricultural development was indigenous; others favor the “two-layer” hypothesis that posits a southward expansion of farmers giving rise to present-day Southeast Asian genetic diversity. By sequencing 26 ancient human genomes (25 from SEA, 1 Japanese Jōmon), we show that neither interpretation fits the complexity of Southeast Asian history: Both Hòabìnhian hunter-gatherers and East Asian farmers contributed to current Southeast Asian diversity, with further migrations affecting island SEA and Vietnam. Our results help resolve one of the long-standing controversies in Southeast Asian prehistory.

Early modern humans and morphological variation in Southeast Asia: fossil evidence from Tam Pa Ling, Laos

Little is known about the timing of modern human emergence and occupation in Eastern Eurasia. However a rapid migration out of Africa into Southeast Asia by at least 60 ka is supported by archaeological, paleogenetic and paleoanthropological data. Recent discoveries in Laos, a modern human cranium (TPL1) from Tam Pa Ling‘s cave, provided the first evidence for the presence of early modern humans in mainland Southeast Asia by 63-46 ka. In the current study, a complete human mandible representing a second individual, TPL 2, is described using discrete traits and geometric morphometrics with an emphasis on determining its population affinity. The TPL2 mandible has a chin and other discrete traits consistent with early modern humans, but it retains a robust lateral corpus and internal corporal morphology typical of archaic humans across the Old World. The mosaic morphology of TPL2 and the fully modern human morphology of TPL1 suggest that a large range of morphological variation was present in early modern human populations residing in the eastern Eurasia by MIS 3.

Bisphosphonates as a supplement to exercise to protect bone during long-duration spaceflight

We report the results of alendronate ingestion plus exercise in preventing the declines in bone mass and strength and elevated levels of urinary calcium and bone resorption in astronauts during 5.5 months of spaceflight.

INTRODUCTION

This investigation was an international collaboration between NASA and the JAXA space agencies to investigate the potential value of antiresorptive agents to mitigate the well-established bone changes associated with long-duration spaceflight.

METHODS

We report the results from seven International Space Station (ISS) astronauts who spent a mean of 5.5 months on the ISS and who took an oral dose of 70 mg of alendronate weekly starting 3 weeks before flight and continuing throughout the mission. All crewmembers had available for exercise a treadmill, cycle ergometer, and a resistance exercise device. Our assessment included densitometry of multiple bone regions using X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) and assays of biomarkers of bone metabolism.

RESULTS

In addition to pre- and post-flight measurements, we compared our results to 18 astronauts who flew ISS missions and who exercised using an early model resistance exercise device, called the interim resistance exercise device, and to 11 ISS astronauts who exercised using the newer advanced resistance exercise device (ARED). Our findings indicate that the ARED provided significant attenuation of bone loss compared with the older device although post-flight decreases in the femur neck and hip remained. The combination of the ARED and bisphosphonate attenuated the expected decline in essentially all indices of altered bone physiology during spaceflight including: DXA-determined losses in bone mineral density of the spine, hip, and pelvis, QCT-determined compartmental losses in trabecular and cortical bone mass in the hip, calculated measures of fall and stance computed bone strength of the hip, elevated levels of bone resorption markers, and urinary excretion of calcium.

CONCLUSIONS

The combination of exercise plus an antiresoptive drug may be useful for protecting bone health during long-duration spaceflight.

Selected fruits reduce azoxymethane (AOM)-induced aberrant crypt foci (ACF) in Fisher 344 male rats

Phytochemicals contribute to the vibrant colors of fruits and it is suggested that the darker the fruit the higher the antioxidative or anticarcinogenic properties. In this study we investigated the possible effects of blueberries (BLU), blackberries (BLK), plums (PLM), mangoes (MAN), pomegranate juice (POJ), watermelon juice (WMJ) and cranberry juice (CBJ) on azoxymethane (AOM)-induced aberrant crypt foci (ACF) in Fisher 344 male rats. Forty-eight male Fisher 344 rats were randomly assigned to eight groups (n=6). The groups were fed AIN-93G as a control (C) diet, the rats fed fruits received AIN-93G+5% fruits and the groups that were given fruits juices received 20% fruit juice instead of water. The rats received subcutaneous injections of AOM at 16 mg/kg body weight at seventh and eighth weeks of age. At 17th week of age, the rats were killed by CO(2) asphyxiation. Total ACF numbers (mean+/-SEM) in the rats fed CON, BLU, BLK, PLM, MNG, POJ, WMJ and CBJ were 171.67+/-5.6, 11.33+/-2.85, 24.0+/-0.58, 33.67+/-0.89, 28.67+/-1.33, 15.67+/-1.86, 24.33+/-3.92 and 39.0+/-15.31. Total glutathione-S-transferase (GST) activity (mICROmol/mg) in the liver of the rats fed fruits (except BLK) and fruit juices were significantly (p<0.05) higher in the rats fed fruits and fruit juices compared with the control. Our findings suggest that among the fruits and fruit juices, BLU and POJ contributed to significant (P<0.05) reductions in the formation of AOM-induced ACF.

Flax seed oil and flax seed meal reduce the formation of aberrant crypt foci (ACF) in azoxymethane-induced colon cancer in Fisher 344 male rats

Flax seed oil and flax seed meal are good sources of omega-3 fatty acids. The objective of this study was to explicate the effects of feeding flax seed oil and flax seed meal on AOM-induced aberrant crypt foci (ACF) in Fisher 344 male rats. Following an acclimatization period, rats were divided into six groups and fed AIN 93G diet Control (C), C+7 and 14% soybean oil (SBO), C+7 and 14% flax seed oil (FSO) and C+10 and 20% flax seed meal (FSM). All rats received 16 mg/kg body weight of AOM at 7 and 8 weeks of age. The rats were euthanized with CO2 at 17 weeks of age. FSM and FSO reduced the incidence of ACF which are putative precursor lesions in the development of colon cancer in the distal colon by 88% and 77%, in the proximal colon by 86% and 87% with a total reduction of 87.5% and 84%, respectively. Glutathione-S-transferase (GST) activities were significantly (P<0.05) higher in rats fed C+7 and 14% FSO and C+10 and 20% FSM, as compared to rats fed C+SBO diets. Results of this study showed that FSO and FSM reduced the incidence of AOM-induced ACF formation and may therefore be effective chemopreventive agents.

Red palm oil suppresses the formation of azoxymethane (AOM) induced aberrant crypt foci (ACF) in Fisher 344 male rats

Red palm oil (RPO) contains significant levels of carotenoids and Vitamin E. In this experiment we compared the inhibitory effects of RPO (7% and 14% levels) and soybean oil (7% and 14%) on azoxymethane (AOM) induced aberrant crypt foci (ACF). Thirty-two male Fisher 344 rats were randomly assigned to four groups. Two groups received AIN-93 G control (C) diet containing 7% and 14% soybean oil (SBO), respectively. Groups 3 and 4 received a treatment diet consisting of 7% and 14% RPO, respectively. The rats received subcutaneous injections of AOM at 16 mg/kg body weight at 7 and 8 weeks of age. At 17 weeks of age rats were killed by CO(2) asphyxiation. Numbers of ACF (mean+/-SE) in the proximal and distal colon were: 39.9 +/- 0.9, 53.8 +/- 2.8, 26.0 +/- 3.0, 27.5 +/- 1.5 and 118.2 +/- 1.7, 125.6 +/- 3.2, 41 +/- 7, 52.3 +/- 1.8 in rats fed 7% SBO, 14% SBO, 7% RPO and 14% RPO, respectively. The results of this study showed that RPO reduced the incidence of AOM induced ACF and may therefore have a beneficial effect in reducing the incidence of colon cancer.

Monitoring sweat calcium using skin patches

The purpose of this study was to determine whether a simple noninvasive sweat collection method using skin patches would be useful in monitoring sweat Ca and to determine changes in dermal Ca loss during a bed rest study testing a resistive exercise countermeasure. The study showed that the technique was highly reproducible: the mean intra-subject variation approached zero and the inter-individual variability (%CV) varied from 18% to 32% for the three anatomical regions (arm, chest, and back) tested. There was less than 10% difference in sweat Ca excretion from different skin regions within the same individual at a given time point. A calculated estimate of total body sweat excretion for 12 bed rest subjects was 35 +/- 4 mg/day (mean +/- SE), close to published whole body measurements. Bed rest testing showed no significant differences with or without exercise when conducted in a temperature-controlled environment. We conclude that the skin patch technique is useful for monitoring changes in sweat Ca.

Dietary inulin suppresses azoxymethane-induced aberrant crypt foci and colon tumors at the promotion stage in young Fisher 344 rats

This study was designed to determine the effect of 10% dietary long-chain inulin on the azoxymethane (AOM)-induced colonic preneoplastic aberrant crypt foci (ACF) and small intestinal and colon tumors at the initiation (I), promotion (P) and I + P stages (20 rats per treatment) in Fisher 344 male weanling rats. After an acclimatization period of 1 wk, groups of Fisher 344 male weanling rats were assigned to consume AIN 93G diet (control) or AIN 93G diet containing 10% inulin. All the rats received 16 mg/kg body AOM dissolved in saline subcutaneously at 7 wk of age followed by a second injection at 8 wk of age. An additional group of five rats received only saline and consumed the control diet. The rats received the assigned diets until asphyxiation by CO(2) at 16 wk of age for the ACF experiment and 45 wk for the end-point tumor experiment. Feed intake, weight gain, diarrheal index, cecal weight, cecal pH, ACF and tumors in the colon were determined. Rats fed inulin had diarrhea after 2 wk of feeding and recovered by approximately 4 wk. Cecal weight was greater in rats fed inulin and cecal pH was lower. The inulin group had more than 66% fewer aberrant crypts and 60% fewer ACF compared with the control group. Tumor incidences in the small intestine and colon of rats in the control, I, P and I + P groups were: 78, 31, 0 and 11% and 90, 73, 69 and 50%, respectively. The corresponding values for the distal portion of the colon were 87, 63, 45 and 33%, respectively. Colon tumors per tumor-bearing rat were 4.2, 3.09, 1.36 and 1.2 for the control, I, P and I + P groups, respectively. All groups differed, P < 0.05. The results of this study indicate that dietary long-chain inulin suppresses AOM-induced ACF formation, an early preneoplastic marker of colon tumorigenesis in rats, and colon tumors, particularly at the promotion stage.

Dietary inulin suppresses azoxymethane-induced preneoplastic aberrant crypt foci in mature Fisher 344 rats

Preneoplastic aberrant crypt foci (ACF) are generally accepted as reliable markers for colon carcinogenesis in animal models. Rat model ACF studies, however, use younger rats, and there are no published reports on the suitability of adult rats for ACF studies. In this study, inulin, a known suppressor of azoxymethane (AOM)-induced ACF, was tested for its ability to suppress ACF formation in mature rats. After a 2-wk acclimation period, 12-mo-old Fisher 344 retired male breeders received two subcutaneous injections of AOM dissolved in saline at weekly intervals. In experiment 1, six groups received 0, 4, 8, 10, 12 and 16 mg AOM/kg body at each injection and were fed AIN-93M diet. In experiment 2, four groups of rats were fed 10 mg AOM/kg body at each injection based on the results of experiment 1, and were fed 0, 2.5, 5 and 10 g long-chain inulin diets/100 g. All the rats were killed after 11-wk feeding periods. In experiment 1, there was a significant (P < 0.05) AOM dose response on ACF formation. Rats fed >10 mg of AOM had greater (P < 0.05) mortality. In experiment 2, there was a significant increase in cecal weight and a decrease in cecal pH from 7.17 in the control group to 6.87, 6.61 and 5.76 in the groups fed inulin at 2.5, 5.0 and 10 g/100 g, respectively. Long-chain inulin dose-dependently reduced ACF incidence in the colon (P < 0.01). Compared with rats fed the control diet, the percentage reductions of ACF in rats fed 2.5, 5.0 and 10 g inulin diets/100 g were 25, 51, and 65, respectively. The results of this study indicate that mature rats can be used as models in ACF studies, and dietary long-chain inulin dose-dependently suppresses AOM-induced ACF formation in Fisher 344 mature male rats.

Bone mineral and lean tissue loss after long duration space flight

The loss of bone and muscle is a major concern for long duration space flight. In December of 1989, we established a collaboration with Russian colleagues to determine the bone and lean tissue changes in cosmonauts before and after flights on the Mir space station lasting 4-14.4 months. Eighteen crew members received a lumbar spine and hip DEXA scan (Hologic 1000W) before and after flight; 17 crew members received an additional whole body scan. All results were expressed as percent change from baseline per month of flight in order to account for the different flight times. The pre-and post-flight data were analyzed using Hotelling's T(2) for 3 groups of variables: spine, neck of femur, trochanter; whole body BMD and subregions; lean (total, legs, arms) and fat (total only). A paired t-test was used as a follow-up to the Hotelling's T(2) to identify the individual measurements that were significantly different. These data define the rate and extent of bone and lean tissue loss during long duration space flight and indicate that the current in-flight exercise program is not sufficient to completely ameliorate bone and muscle loss during weightlessness.

Muscle volume, MRI relaxation times (T2), and body composition after spaceflight

Postflight changes in muscle volume, calf muscle transverse relaxation time, and total body composition were measured in 4 crewmembers after a 17-day mission and in 14-16 crewmembers in multiple shuttle/Mir missions of 16- to 28-wk duration. During the 17-day mission, all muscle regions except the hamstrings significantly decreased 3-10% compared with baseline. During the shuttle/Mir missions, there were significant decreases in muscle volume (5-17%) in all muscle groups except the neck. These changes, which reached a new steady state by 4 mo of flight or less, were reversed within 30-60 days after landing. Postflight swelling and elevation of calf muscle transverse relaxation time persisted for several weeks after flight, which suggests possible muscle damage. In contrast to the 17-day flight, in which loss in fat, but not lean body mass, was found (25), losses in bone mineral content and lean body mass, but not fat, were seen after the longer shuttle/Mir missions. The percent losses in total body lean body mass and bone mineral content were similar at approximately 3.4-3.5%, whereas the pelvis demonstrated the largest regional bone loss at 13%.

T2 vertebral bone marrow changes after space flight

Bone biopsies indicate that during immobilization bone marrow adipose tissue increases while the functional cellular fraction decreases. One objective of our Spacelab flight experiment was to determine, using in vivo volume-localized magnetic resonance spectroscopy (VLMRS), whether bone marrow composition was altered by space flight. Four crew members of a 17 day Spacelab mission participated in the experiment. The apparent cellular fraction and transverse relaxation time (T2) were determined twice before launch and at several times after flight. Immediately after flight, no significant change in the cellular fraction was found. However, the T2 of the cellular, but not the fat component increased following flight, although to a variable extent, in all crew members with a time course for return to baseline lasting several months. The T2 of seven control subjects showed no significant change. Although these observations may have several explanations, it is speculated that the observed T2 changes might reflect increased marrow osteoblastic activity during recovery from space flight.

Future human bone research in space

Skylab crewmembers demonstrated negative calcium (Ca) balance reaching about -300 mg/day by flight day 84. Limited bone density (BMD) measurements documented that bone was not lost equally from all parts of the skeleton. Subsequent BMD studies during long duration Russian flights documented the regional extent of bone loss. These studies demonstrated mean losses in the spine, femur neck, trochanter, and pelvis of about 1%-1.6% with large differences between individuals as well as between bone sites in a given individual. Limited available data indicate postflight bone recovery occurred in some individuals, but may require several years for complete restoration. Long duration bedrest studies showed a similar pattern of bone loss and calcium balance (-180 mg/day) as spaceflight. During long duration bedrest, resorption markers were elevated, formation markers were unchanged, 1,25 vitamin D (VitD) and calcium absorption were decreased, and serum ionized Ca was increased. Although this information is a good beginning, additional spaceflight research is needed to assess architectural and subregional bone changes, elucidate mechanisms, and develop efficient as well as effective countermeasures. Space research poses a number of unique problems not encountered in ground-based laboratory research. Therefore, researchers contemplating human spaceflight research need to consider a number of unique problems related to spaceflight in their experimental design.

Bifidobacterium longum and lactulose suppress azoxymethane-induced colonic aberrant crypt foci in rats

Bifidobacterium longum has been shown to afford protection against colon tumorigenesis. Lactulose, a keto analog of lactose, serves as a substrate for preferential growth of Bifidobacterium. It is not known whether feeding lactulose along with B. longum will have any advantage over feeding of B. longum alone. To test this combination effect, 61 male Fisher 344 weanling rats were divided into four groups of 15 rats each (16 in the control group) and assigned to one of the following four diets for 13 weeks: (i) AIN76A (control, C); (ii) C + 0.5% B. longum (C+Bl, containing 1 x 10(8) viable cells/g feed); (iii) C + 2.5% lactulose (C+L); (iv) C + 0.5% B. longum + 2.5% lactulose (C+Bl+L). All animals received a s.c. injection of azoxymethane at 16 mg/kg body wt at 7 and 8 weeks of age. Colons of 10 rats from each dietary group were analyzed for aberrant crypt foci (ACF), which are preneoplastic markers. Colonic mucosa and livers from five rats were analyzed for glutathione S-transferase (GST, a Phase II enzyme marker). Results indicate that feeding of lactulose and B. longum singly and in combination reduces the number of ACF (P = 0.0001) and the total number of aberrant crypts significantly (P = 0.0005). The total number of ACF in diets C, C+Bl, C+L and C+Bl+L were 187 +/- 9, 143 +/- 9, 145 +/- 11 and 97 +/- 11 respectively. There was no significant difference in weight gain among treatments. Colonic mucosal GST levels were significantly (P = 0.05) higher in the Bl and L groups compared with group C. Initially there was a mild diarrhea in lactulose-fed rats. There was a positive correlation between higher cecal pH and number of ACF. Results of the study indicate that Bifidobacterium and lactulose exert an additive antitumorigenic effect in rat colon.

Hologic QDR 2000 whole-body scans: a comparison of three combinations of scan modes and analysis software

This study reports on the short-term in vivo precision and absolute measurements of three combinations of whole-body scan modes and analysis software using a Hologic QDR 2000 dual-energy X-ray densitometer. A group of 21 normal, healthy volunteers (11 male and 10 female) were scanned six times, receiving one pencil-beam and one array whole-body scan on three occasions approximately 1 week apart. The following combinations of scan modes and analysis software were used: pencil-beam scans analyzed with Hologic's standard whole-body software (PB scans); the same pencil-beam analyzed with Hologic's newer "enhanced" software (EPB scans); and array scans analyzed with the enhanced software (EA scans). Precision values (% coefficient of variation, %CV) were calculated for whole-body and regional bone mineral content (BMC), bone mineral density (BMD), fat mass, lean mass, %fat and total mass. In general, there was no significant difference among the three scan types with respect to short-term precision of BMD and only slight differences in the precision of BMC. Precision of BMC and BMD for all three scan types was excellent: < 1% CV for whole-body values, with most regional values in the 1%-2% range. Pencil-beam scans demonstrated significantly better soft tissue precision than did array scans. Precision errors for whole-body lean mass were: 0.9% (PB), 1.1% (EPB) and 1.9% (EA). Precision errors for whole-body fat mass were: 1.7% (PB), 2.4% (EPB) and 5.6% (EA). EPB precision errors were slightly higher than PB precision errors for lean, fat and %fat measurements of all regions except the head, although these differences were significant only for the fat and % fat of the arms and legs. In addition EPB precision values exhibited greater individual variability than PB precision values. Finally, absolute values of bone and soft tissue were compared among the three combinations of scan and analysis modes. BMC, BMD, fat mass, %fat and lean mass were significantly different between PB scans and either of the EPB or EA scans. Differences were as large as 20%-25% for certain regional fat and BMD measurements. Additional work may be needed to examine the relative accuracy of the scan mode/software combinations and to identify reasons for the differences in soft tissue precision with the array whole-body scan mode.

Otological and habilitative management of children with Down syndrome

It has been well-established that children with Down syndrome experience a high incidence of persistent conductive hearing loss because of their predisposition to stenosis of the external auditory canal (EAC), cerumen impaction, serous otitis media (SOM), and cholesteatoma. Because this hearing problem may be a primary cause of the spoken communication skills in these children being far below their cognitive ability, assertive management is required. The authors present an aggressive multi-discipline treatment model that is instituted during the first year of life in an infant with Down syndrome. Reconstruction of the EAC, amplification technology, and speech/language intervention that emphasizes auditory-verbal (A/V) therapy are discussed. In a pilot study, we compared the language development of six infants with Down syndrome who received aggressive treatment during their first year of life (group A) to six infants who did not (group B). The results showed age-appropriate oral language development for the infants in group A.