Persistence of lactase activity among Northern Europeans: A weighing of evidence for the calcium absorption hypothesis

Considered in this paper is a broad range of evidence bearing on the calcium absorption hypothesis that has been advanced to explain high frequencies of the gene for persistence of lactase activity (PLA) among adults in northern Europe. According to that hypothesis, lactase‐sufficient individuals in early northern Europe enjoyed a selective advantage over lactase‐deficient ones that led to high incidences of PLA in adults of the region. Northern Europeans, the hypothesis goes, suffered from a dietary shortage of vitamin D and, in addition, were unable to synthesize adequate vitamin D from the sun's ultraviolet radiation because of northern Europe's cloudiness and its location in higher latitudes. This led to chronic vitamin D deficiency along with a reduced ability to absorb calcium from milk and lactose‐rich dairy products. As a result, the deficiency diseases rickets—which affects infants and children and can leave a child with bowlegs and other bone defects—and osteomalacia—which weakens and deforms the bones of adults—were common in early northern Europe, and represented powerful selective forces that contributed to development of the highly depigmented skin that is typical of the region's peoples. In addition, the hypothesis goes, calcium absorption was enhanced by a process independent of vitamin D. Such enhancement, found especially or solely among lactase‐sufficient individuals, was brought on by ingestion of lactose in milk and milk products. Thus, persons who enjoyed high lactase activity through life were favored in the struggle for survival, which ultimately led northern European peoples to have among the highest incidences of PLA in the world.

In this article, evidence, much of it recent, is presented to show that lactase‐deficient humans are able to absorb calcium from milk as readily, or nearly as readily, as lactase‐sufficient humans. Evidence is also presented that rickets and osteomalacia occur in parts of the world that have an abundance of sunshine, whether originating from customs that limit exposure to sunshine or otherwise; that heavy cloud cover and high latitude need not result in vitamin D deficiency, rickets, and osteomalacia; that, indeed, osteological evidence from archeological sites in northern Europe indicates that rickets and osteomalacia were quite rare in antiquity; that those conditions appear to have become common in northern Europe only with the advent of the Industrial Revolution, too short a time to have been a significant factor in bringing on the high incidences of PLA that prevail today; and that, indeed, the calcium absorption hypothesis is not confirmed by historical, osteoarcheological, or bio‐medical evidence.     

Postnatal maternal deprivation and pubertal stress have additive effects on dopamine D2 receptor and CaMKII beta expression in the striatum

The goal of this study was to determine whether two stressors commonly used to model aspects of neuropsychiatric disease in rats have an additive effect on striatal dopamine type 2 receptor (D2R) expression, a key player in the etiology of neuropsychiatric disease.     

A serial echocardiographic study of myocardial abscess in a patient surviving staphylococcal septicemia

2D echocardiography was performed on a 4-year-old child suffering from right thigh abscess due to MRSA infection following diagnosis of pericardial effusion by USG abdomen. It revealed myocardial abscess and pericardial effusion. This child underwent series of 2D echocardiographic studies which showed image appearance of myocardial abscess with its time course of healing.     

A simulator for percutaneous hepatic microwave thermal ablation under ultrasound guidance

The purpose of this study was to provide a simulation therapy environment for microwave thermal ablation (MWA) under the guidance of ultrasound, and to present an inexpensive and portable simulator built on real patient-based pre-operative computed tomography (CT) data. We established an experimental simulation system for teaching MWA and present the results of a preliminary evaluation of the simulator’s realism and utility for training. The system comprises physical elements of an electromagnetic tracking device and an abdominal phantom, and software elements providing three-dimensional (3D) image processing tools, real-time navigation functions and objective evaluation function module. Details of the novel aspects of this system are presented, including a portable electromagnetic tracking device, adoption of real patient-based pre-operative CT data of liver, operation simulation of MWA, and recording and playback of the operation simulation. Patients with liver cancer were selected for evaluation of the clinical application value of the experimental simulation system. A total of 50 consultant interventional radiologists and 20 specialist registrars in radiology rated the simulator’s hardware reality and overall ergonomics. Results show that the simulator system we describe can be used as a training tool for MWA. It enables training with real patient cases prior to surgery, and it can provide a realistic simulation of the actual procedure.     

Effects of laparoscopic Roux-en-Y gastric bypass on bone mineral density and markers of bone turnover

BackgroundDespite multiple beneficial effects of weight loss after laparoscopic Roux-en-Y gastric bypass (LRYGB), the influence on bone mineral density (BMD) remains largely unknown. Our objective was to evaluate the changes in BMD and serum/urine bone markers after LRYGB.MethodsThirty-four women undergoing LRYGB were prospectively enrolled and underwent bone densitometry and serum/urine analysis preoperatively and 1 year postoperative. Changes≥.025 g/cm² in hip, femoral neck, and spine BMD and decreases>2% in total BMD were considered significant. Statistical analysis included paired t tests and McNemar’s test.ResultsMean age was 44.6 years. Body mass index at the preoperative and 1-year postoperative intervals were 46.7 and 29.6 kg/m², respectively. Mean hip, femoral neck, and spine (L1–L4) BMD was 1.191 versus 1.087 g/cm² (P< .001), 1.105 versus 1.032 g/cm² (P< .001), and 1.323 versus 1.277 g/cm² (P< .001) at the preoperative and 1 year postoperative intervals, respectively. Mean total BMD decreased from 1.328 preoperatively to 1.251 g/cm² at 1 year postoperative (P<.001). The decreases in BMD were 5.8%, 6.5%, 3.5%, and 8.8% for hip, femoral neck, spine (L1–L4) and total BMD from preoperative to 1 year postoperative. The proportion of patients with low vitamin D levels decreased from 55% preoperatively to 21% at 1 year postoperative (P = .004). Elevated osteocalcin and bone alkaline phosphatase was observed in 4% and 63% (P<.001), and 14% and 41% (P = .011) of patients preoperatively and at 1 year postoperative, respectively.ConclusionBMD and bone markers changed significantly after LRYGB. Current recommendations for supplementation in post-LRYGB women may need to be reevaluated.     

Can Montgomery tubercles impact aesthetic 3D nipple-areolar complex tattooing? An anatomical,quantitative analysis of breast cancer patients

PurposeWe aimed to establish a relationship between the amount of Montgomery tubercles (MTs) per nipple-areolar complex (NAC) given patient characteristics such as age, BMI, menopausal status, race/ethnicity, and NAC size to better inform current 3D NAC tattooing practices.MethodsPreoperative photographs of patients pursuing breast reconstruction after mastectomy in 2010 through 2018 were reviewed. The number of MTs on each native NAC was quantified. The impact of patient factors on the quantity of MTs was evaluated via Pearson correlation and bivariate analyses.ResultsTwo hundred and eleven patients (399 breasts) were reviewed. On average, patients had 5.0 ± 5.2 MTs (range, 0–25 MTs). Number of MTs did not correlate with patient age, BMI, or NAC size. Premenopausal females were more likely than postmenopausal females to have a greater number of MTs per breast (p-value = 0.0183).ConclusionsPostmastectomy patients desiring a more “youthful” NAC may consider additional MTs when pursuing 3D NAC tattooing.     

Practical approaches to labelling terminal alkynes with deuterium

Base catalysed exchange with sodium hydroxide, calcium oxide or N,N,N,N-tetramethylguanidine in deuterium oxide is a viable procedure for the preparation of terminally deuterated alkynes for those alkynes stable to strong base. The use of silver perchlorate as a catalyst is an alternative practical option when labelling alkynes which are sensitive to base or contain functionalities which would lead to labelling elsewhere in the molecule. Labelling with this catalyst takes place smoothly at ambient temperature in a mixture of N,N-dimethylformamide and deuterium oxide.