Dental indicators of adaptation in the Sahara Desert during the Late Holocene.

The present paper examines dental diseases and linear enamel hypoplasia among the Garamantes, a Late Holocene Saharan population, and aims to draw conclusions about nutrition and adaptation to a hyper-arid environment. Archaeological evidence suggests that the Garamantian diet included animal protein and local, Mediterranean and Near Eastern plants. Moreoever, although the Garamantes had developed urban centres, the size of these was not large enough to allow for particularly unhygienic conditions to appear. The above archaeological findings were partly corroborated by the current bioarchaeological study. At an intra-population level, the Garamantes showed limited sex differences in dental disease prevalence, while all dental conditions increased in frequency with age, as expected. At an inter-population level, the frequency of all dental conditions was comparable to that found among other North African groups, with the exception of ante-mortem tooth loss. The low frequency of most dental conditions is an indication that the Garamantian diet was overall balanced, while the high frequency of ante-mortem tooth loss may be related to factors such as oral hygiene, food preparation or eating mode, which cannot be controlled for osteologically. Finally, the low frequency of enamel hypoplasia suggests either that the Sahara did not inflict particular stresses on the population, or, more likely, that the Garamantes had developed effective mechanisms for coping with their natural environment.

New limits on Planck scale Lorentz violation in QED.

Constraints on possible Lorentz symmetry violation (LV) of order E/M(Planck) for electrons and photons in the framework of effective field theory (EFT) are discussed. Using (i) the report of polarized MeV emission from GRB021206 and (ii) the absence of vacuum Cerenkov radiation from synchrotron electrons in the Crab Nebula, we improve previous bounds by 10(-10) and 10(-2), respectively. We also show that the LV parameters for positrons and electrons are different, discuss electron helicity decay, and investigate how prior constraints are modified by the relations between LV parameters implied by EFT.

A strong astrophysical constraint on the violation of special relativity by quantum gravity.

Special relativity asserts that physical phenomena appear the same to all unaccelerated observers. This is called Lorentz symmetry and relates long wavelengths to short ones: if the symmetry is exact it implies that space-time must look the same at all length scales. Several approaches to quantum gravity, however, suggest that there may be a microscopic structure of space-time that leads to a violation of Lorentz symmetry. This might arise because of the discreteness or non-commutivity of space-time, or through the action of extra dimensions. Here we determine a very strong constraint on a type of Lorentz violation that produces a maximum electron speed less than the speed of light. We use the observation of 100-MeV synchrotron radiation from the Crab nebula to improve the previous limit by a factor of 40 million, ruling out this type of Lorentz violation, and thereby providing an important constraint on theories of quantum gravity.

Uncoupling of bone turnover following hip replacement.

Studies using total hip replacement surgery as a model for acute hip injury have shown that bone mineral density of the proximal femur decreases 6-18% in the 6 months following surgery. To examine the acute biochemical mechanism associated with bone loss, we measured two indicators of bone formation [serum osteocalcin (OC), serum bone-specific alkaline phosphatase (BSAP)], as well as two markers for bone resorption [urine and serum N-telopeptide cross-linked collagen type 1 (NTx)], in 20 patients (10 men, 10 women, mean age 59.4 years) prior to hip replacement and 1-2 days postsurgery. The average OC value (ng/ml) decreased by 57.3% following surgery (7.5 +/- 4.3 to 3.2 +/- 1.1, P <0.001), and the average BSAP level (U/L) decreased by 27.6% (19.9 +/- 5.6 to 14.4 +/- 3.7, P <0.001). In contrast, levels of urine NTx (nmol BCE/mmol Cr) did not change significantly after the surgery (73.9 +/- 47.2 to 70.1 +/- 29.7). In addition, there was no change in serum NTx (nmol BCE) after surgery (11.8 +/- 2.3 to 11.8 +/- 3.0). Six months after surgery, bone mass had not changed significantly from baseline. These findings suggest that there is an uncoupling of bone turnover following hip replacement surgery which is characterized by significant reductions in bone formation without compensatory decreases in bone resorption, potentially leading to bone loss. Longer periods of follow-up are needed to assess long-term bone mass changes.

King Solomon's miners--starvation and bioaccumulation? An environmental archaeological investigation in Southern Jordan.

Copper mining and smelting were important activities in various predesert wadis during the Iron Age, Nabatean, Roman, and Byzantine periods in southern Jordan and major spoil tips together with slag heaps remain as a legacy of such enterprises. Barley has grown in the area for a prolonged period and currently wild barley plants are affected by toxic cations, which reduce their yields. It is considered that such plants provide an adequate model to assess how similar plants would have performed, in terms of productivity, in the past. The population of miners/slaves, guards, etc., would have been subject to bioaccumulation of heavy metals, which conceivably would have led to detrimental effects on their health. Inhalation and ingestion of particulate pollutants cannot be discounted. It is argued that the population may have been further weakened as a consequence of food shortage, due to reduced plant productivity, as cereals are important foods for both humans and the animals upon which they are dependent. A sizeable mining community could only have been maintained by large-scale importation of food or a massive intensification of agricultural activity.

Intermediate clinical follow-up of a dual-radius acetabular component.

In this study, 92 primary total hip arthroplasties were performed in 83 patients using a porous-coated, dual-radius, cementless, acetabular component. All hips underwent line-to-line dome reaming with press-fit implantation that was judged to have complete bone contact. This acetabular shell provides a 1-mm oversized peripheral rim, which adds excellent initial stability while allowing complete bone contact in all hips. No fractures occurred. In 83% of hips, adjunctive screw fixation was not necessary. At a minimum of 4 years, follow-up, there were no revisions, no acetabular migration, one case of acetabular erosion consistent with osteolysis, and the average Harris Hip Score was 95. The design features of this new acetabular component have provided excellent fixation with complete initial bone contact, resulting in satisfactory intermediate clinical and radiographic results. The design provides excellent peripheral stability and complete bone contact.

Removal and reinsertion of cemented femoral components during acetabular revision.

A retrospective review examined all patients who underwent removal and reinsertion of a cemented femoral component during isolated acetabular revision by one surgeon since 1981. All components were reinserted into the original, intact cement mantle. Forty-two hips with 2- to 10-year follow-up periods were reviewed. Average follow-up period since revision was 67 months. Average followup period since index procedure was 191 months. Average Harris hip score increased from 61 before surgery to 90 at follow-up examination. Two femurs are definitely loose by Harris criteria, but both are asymptomatic. One solidly fixed femoral component was revised because of joint instability. Two hips have postrevision cement fractures. One patient has mild thigh pain. In vitro testing of eight cadaver hips showed no increase in rotational micromotion following removal and reinsertion. It is concluded that this technique aids in isolated acetabular revision surgery by avoiding the complications of trochanteric osteotomy and femoral revision, improving acetabular exposure, and decreasing operative time with minimal risk of disrupting femoral component fixation.

Predictors of fear of falling in dizzy and nondizzy elderly.

Fear of falling may constitute an independent risk factor for disability, leading older people to unnecessarily restrict their activity. Sixty older adults with chronic dizziness and 66 healthy controls were studied to help clarify the interrelationships among demographic factors, psychological status, physical health, and fear of falling. Chronic dizziness was strongly associated with fear of falling; among dizzy patients, nearly half (47%) expressed fear of falling, in comparison with 3% of controls. In participants with dizziness, 3 factors predicted fear of falling: an activity of daily living score, the revised Symptom Checklist 90 Depression (Derogatis, 1983) score, and stability when standing with feet together. These results support the concept that fear of falling is multiply determined and that psychological factors play a major role in influencing the symptoms and responses in many older patients with dizziness.

Wear debris from bipolar femoral neck-cup impingement. A cause of femoral stem loosening.

The source of wear debris in total hip arthroplasty may occur at various interfaces: metal-ultra-high molecular-weight polyethylene bearings, metal-cement micromotion, bone-cement interfaces, and implant coatings. Wear-induced osteolysis may result in a spectrum of radiographic changes from radiolucent lines to massive osteolysis. Subsequent loosening of the implant may occur and revision may be difficult because of bone deficiencies. Impingement of the femoral neck on the acetabular component may result in polyethylene and/or metal debris, leading to early femoral stem loosening. The five cases presented, involving six hips, illustrate how bipolar cup-stem impingement may result in significant wear-induced femoral osteolysis.

Estimation of urinary aldosterone using thin-layer chromatography and fluorimetry.

AIMS: To develop a fluorimetric method for the estimation of urinary aldosterone; to establish a normal range in 24 hour and overnight urine samples; and to investigate the use of overnight urines for detecting hyperaldosteronism. METHODS: Essential steps include hydrolysis of the 18 conjugate to release aldosterone and its oxidation with Benedict's solution, followed by thin-layer chromatography on silica gel and development of fluorescence on the plate with sulphuric acid. RESULTS: There was a linear correlation between the amount of aldosterone and the area under the peak on the chromatogram. The mean intra-assay and interassay coefficients of variation were 4.4% and 6.8%, respectively. The mean aldosterone excretion in 67 adults was 15.7 (SD 8.1) nmol/24 hours. The mean overnight excretion in 65 adults was 2.6 (1.4) nmol/8 hours. The method detected raised concentrations in patients with primary and secondary aldosteronism. CONCLUSIONS: This technique provides an accurate means of assaying urinary aldosterone. Overnight estimations seem to be as effective as 24 hour assays for identifying patients with hyperaldosteronism.

Wheelchair selection.

Selection of an appropriate wheelchair is an essential part of discharge planning. Although the physical therapist plays the primary role in wheelchair recommendations, all those involved in patient care need to have a basic understanding of factors that are considered. This article discusses these factors, which include patient diagnosis, prognosis, medical status, functional status, mental status, environment, and funding. It also emphasizes that the decision-making process is a team effort and that the patient and his/her family are key members of that team. Basic terminology, wheelchair components, and available options for wheelchairs and wheelchair cushions are addressed.

Plasma melatonin levels in anorexia nervosa.

Plasma melatonin levels were measured at three-hourly intervals over 24 hours in 11 women with untreated anorexia nervosa, and in nine healthy women of normal weight. The circadian rhythm was unaltered but the nocturnal secretion of melatonin was significantly greater in anorectics. It is possible that this was related to nocturnal hypoglycaemia.

Acrocyanosis in anorexia nervosa.

Acrocyanosis, an uncommon disorder of the peripheral circulation, may occur in patients with anorexia nervosa. It is not known why this should be, nor whether acrocyanosis correlates with any other features of the disorder. The findings in an unselected series of 155 anorectics are reported. Acrocyanosis occurred in 32 and was more prevalent among the more severely ill. It was associated also with pallor of the face and trunk, slower pulse rates and higher fasting plasma glucose levels. Acrocyanosis could represent a more extreme form of a heat conserving mechanism not uncommon in anorectics. The possible relationship between peripheral vascular changes and plasma glucose levels requires further study.

Total parenteral nutrition. Conquering the complexities.

Delivery of total parenteral nutrition (TPN) is a complex procedure requiring a basic knowledge of nutritional physiology and an understanding of the impact of various disease states on utilization of nutrient substrates. The goals of TPN are to reverse catabolism, promote anabolism, and build structural protein. It is important to infuse an adequate amount of calories and protein but to avoid the stress of overfeeding. Various laboratory values may be monitored to ensure that each of the nutrients administered is being adequately tolerated by the patient. Keeping these principles in mind, primary care physicians can deliver a TPN regimen specifically suited for individual patients and can anticipate and prevent any potential complications.

Fluorimetric method for simultaneous estimation of cortisol, corticosterone, and testosterone in plasma.

The simultaneous estimation of steroids in plasma was carried out by the assay of cortisol, corticosterone, and testosterone. The method entails separation by means of thin layer chromatography, followed by conversion to a fluorophore and fluorimetric measurement. Its major advantages are its high specificity, its ability to detect unknown substances, and the ease with which it can be performed. The method has acceptable levels of accuracy and precision and the normal values obtained by it compare well with those given by methods in general use.

Femoral revision total hip arthroplasty using a long-stem femoral component. Clinical and radiographic analysis.

Proximal femoral bone stock deficiencies exist during many femoral revision arthroplasties, thus providing inadequate support and fixation for conventional-length cemented femoral components. The authors analyzed the long-term clinical and roentgenographic results of 165 hips requiring femoral revision arthroplasty with a long-stem femoral prosthesis. Intraoperative complications occurred in 23% of hips, with femoral perforations in 16% and femoral fractures in 5%. Of 110 hips with at least 5 years of follow-up study (average, 6.7 years), functional ratings were graded excellent in 34%, good in 36%, fair in 17%, and poor in 13%. Failures occurred in 17 hips (12%) and were attributed to aseptic loosening (11 hips), femoral component fracture (2), femoral shaft fracture (1), and sepsis (3). Symptomatic trochanteric separations occurred in 16% of hips. Rerevision or resection arthroplasty was required in 7 hips (5%) and recommended for another 10 hips (7%). Cemented long-stem femoral components (versus cemented conventional-length stems) decrease the extent and progression of femoral lucencies, thereby lowering the incidence of mechanical failures and improving long-term functional results in cemented femoral revision arthroplasty.