From the Cover: Hominids adapted to metabolize ethanol long before human-directed fermentation

Paleogenetics is an emerging field that resurrects ancestral proteins from now-extinct organisms to test, in the laboratory, models of protein function based on natural history and Darwinian evolution. Here, we resurrect digestive alcohol dehydrogenases (ADH4) from our primate ancestors to explore the history of primate–ethanol interactions. The evolving catalytic properties of these resurrected enzymes show that our ape ancestors gained a digestive dehydrogenase enzyme capable of metabolizing ethanol near the time that they began using the forest floor, about 10 million y ago. The ADH4 enzyme in our more ancient and arboreal ancestors did not efficiently oxidize ethanol. This change suggests that exposure to dietary sources of ethanol increased in hominids during the early stages of our adaptation to a terrestrial lifestyle. Because fruit collected from the forest floor is expected to contain higher concentrations of fermenting yeast and ethanol than similar fruits hanging on trees, this transition may also be the first time our ancestors were exposed to (and adapted to) substantial amounts of dietary ethanol.One trend in modern medicine attributes diseases in humans to an incomplete adaptation of the human genome to new challenges presented by our changing cultural and demographic environment (1). This attribution is especially convincing for some “lifestyle” diseases. For example, the recent increase in sugar consumption (including sucrose and fructose) is associated with the emergence of obesity, diabetes, and hypertension (2). Under an evolutionary paradigm, an organism fully adapted to a sugar-rich diet would not be expected to become diseased by consuming sugars, suggesting that humankind has not had enough time to adapt to a modern diet rich in such sugars.It is unclear whether the human genome has had more time to adapt to dietary ethanol (“alcohol” in the vernacular), which also produces a disease spectrum (“alcoholism”) common today in many societies (3). In one historical model, ethanol was not a significant part of the hominin “Paleolithic diet” (4) and was also absent from the diets of earlier ancestors. Rather, the model holds that ethanol entered our diets in significant amounts only after humans began to store surplus food (possibly because of the advent of agriculture) and subsequently developed the ability to intentionally direct the fermentation of food (∼9,000 y ago (5), perhaps as a means of preservation (6). In this model, alcoholism as a disease reflects insufficient time since humans first encountered ethanol for their genome to have adapted completely to ethanol. As such, the allelic variants of enzymes in the ethanol metabolic pathway that disfavor ethanol consumption (e.g., ADH1B*47His and ALDH2*487Lys, both of which lead to an accumulation of acetaldehyde—a toxic intermediate that causes headache, nausea, and general discomfort) represent an early stage of adaptation, possibly in association with pathogenic infections (7–10).In an alternative model, primates may have ingested ethanol via frugivory as early as 80 million y ago (Ma), a time corresponding to the origin and diversification of primates (11) and when angiosperm plants first produced fleshy fruits that can become infected by yeast capable of the accumulating ethanol via fermentation (12). In one version of this model, small amounts of ethanol present in slightly fermenting fruit attached to trees attracted arboreal primates foraging in the trees. In this version, our contemporary attraction to ethanol is an “evolutionary hangover” that ceased to be beneficial once that attraction became redirected to beverages with high concentrations of ethanol (13), made possible only after humans developed the tools allowing them to intentionally direct fermentation (and enhanced with the advent of technology to distill ethanol to higher concentrations). Another version of the “ethanol early” model for ethanol exposure recognizes that ethanol itself, as well as the food naturally containing it, can be a significant source of nutrition. This model posits that any organism with metabolic adaptations that permit the exploitation of ethanolic food would have access to a specialized niche or important fallback foods unavailable to organisms without this metabolic capacity.Paleogenetics is an emerging field designed to address such natural historical hypotheses and, in particular, to distinguish between competing historical models (14). Here, to gain a genetic perspective on the natural history of the interaction between our human ancestors and ethanol, we examined the evolution of Class IV alcohol dehydrogenases (ADH4) (see SI Text for a discussion of the various synonyms used within the ADH family). These digestive enzymes are abundant in the stomach, esophagus, and tongue of primates and are active against a wide range of alcohols. Thus, ADH4 is the first alcohol-metabolizing enzyme to encounter ethanol that is imbibed (15), and several studies indicate that ADH4 contributes significantly to the first-pass metabolism of ethanol in humans (16).ADH4 is also active against retinol (in vitro), and ADH4’s high catalytic efficiency for retinol (as defined by its k_cat/K_M ratio) suggests it may play a role in retinoic acid biosynthesis (17). Mice with inactivated ADH4 genes, however, display few complications associated with retinoid metabolism except under extreme conditions of dietary retinol excess or dietary retinoid deficiency (18, 19). Further, dietary retinoids occur in the form of retinyl esters (from animal foods) or carotenoids (from plant foods); these forms of provitamin A are not substrates for ADH4 present in the upper gastrointestinal track and are converted into retinol only after entering the small intestines. Geraniol, however, is a monoterpenoid that is structurally similar to retinol and is commonly found in plants as an antifeedant, making it a physiologically relevant substrate for ADH4 in herbivorous primates.We therefore tested alternative models for the history of primate exposure to ethanol by comparing the enzymatic efficiencies of modern and ancestral ADH4 enzymes toward geraniol and ethanol. These comparisons identified a dramatic evolutionary transition from an ethanol-inactive ADH4 to an ethanol-active ADH4 in our hominin ancestors ∼10 million y ago.This study focuses on the evolution of one component of ethanol metabolism, ADH4. Ethanol metabolism is complex and involves other ethanol-metabolizing enzymes [e.g., ADH1, ADH2, and the microsomal ethanol oxidizing system (MEOS)], enzymes involved in the downstream metabolism of by-products from ethanol metabolism (e.g., ALDH2, which oxidizes acetaldehyde created from ethanol), and enzymes indirectly affected by the by-products of ethanol metabolism (e.g., ALDH1). A more nuanced understanding of primate adaptation to ethanol will develop as future work examines these related enzymes.     

瘢痕疙瘩家系Fas基因的突变：2个家系10份标本分析

目的:观察瘢痕疙瘩家系样本中Fas基因有无突变,探讨Fas基因突变在瘢痕疙瘩形成中的意义。方法:实验于2005-01/05在上海基康公司完成。①标本来自南方医科大学南方医院整形外科2005年收集的A和B两个瘢痕疙瘩家系,所有参与观察的家系成员均签署知情同意书。②采用聚合酶链反应及基因测序技术,分别以A家系两例患者的瘢痕疙瘩组织为观察对象,以其周围正常皮肤及外周静脉血作为自身对照;其配偶的外周静脉血作为正常对照。并以B家系中两例患者的外周静脉血作为不同家系间的对照。共取10份样本,4份组织样本,6份静脉血标本。检测10份样本中Fas基因外显子1～9的基因序列。结果:①基因测序发现所检测的10个瘢痕疙瘩家系标本Fas基因的1～8外显子均未发现突变。②2份瘢痕疙瘩组织标本在第9外显子编码区的11bp,53bp两个位点上存在单个碱基的基因突变或多态性改变。结论:瘢痕疙瘩Fas基因外显子9区段的基因结构异常极有可能造成Fas蛋白的功能改变,从而导致身体局部瘢痕疙瘩的形成。     

H-2-restricted cytotoxic effectors generated in vitro by the addition of trinitrophenyl-conjugated soluble proteins

Murine spleen cells from normal donors were cultured in vitro with trinitrobenzene sulfonate (TNBS)-conjugated soluble proteins, i.e., bovine gamma globulin (TNP-BGG) or bovine serum albumin (TNP-BSA). Addition of 100 μg of any of these TNP-proteins to the spleen cell cultures led to the generation of cytotoxic T-cell effectors which were H-2-restricted and TNP- specific. The lytic potential of such effectors was comparable to that generated by sensitization with TNBS-modified syngeneic cells, and was restricted to haplotypes shared at the K or K plus I-A, or the D regions of the H-2 complex. Greater effecter cell activity was generated by addition of TNP-BGG against TNBS-modified targets which shared K plus I-A than against modified targets which shared the D region with the responding cells, which suggests that the same immune response genes are involved when the response is generated by the addition of TNP-conjugated soluble proteins or of TNBS- modified cells. H-2-restricted, TNP-specific effecter cells were generated by culturing mouse spleen cells with syngeneic cells which had been preincubated with TNP- BGG or TNP-BSA for 1.5 h. The addition of unconjugated soluble proteins to the cultures did not result in cytotoxic effectors detectable on H-2-matched targets, whether the targets were prepared by modification with TNBS, or by incubation with either the unconjugated or TNP-conjugated proteins. Depletion of phagocytic cells in the tumor preparation by Sephadex G-10 column fractionation before incubation with TNP-BSA had no effect on their lysis by the relevant effector cells. Immunofluorescent staining of tumor target cells with anti-TNP antibodies indicated that TNP could be detected on the tumor cells within 10 rain of incubation with TNP-BSA. The cytotoxic response generated by addition of the TNP-proteins to spleen cell cultures was found to be T-cell dependent at the effector phase, as shown by the sensitivity of the lytic phase to absorbed RAMB and complement. Furthermore, the response did not appear to be attributable to antibody-dependent cellular cytotoxicity. Three mechanisms were considered which could account for the generation of H-2-restricted, TNP-specific, cytotoxic T-cell effectors by the addition of soluble TNP-proteins. These include covalent linkage of activated TNP groups from the soluble proteins to cell surface components, macrophage processing of the soluble conjugates and presentation to the responding lymphocytes in association with H-2-coded self structures, or hydrophobic interaction of the TNP-proteins to cell surfaces. Results obtained from sodium dodecyl sulfate gel patterns indicating that cell-bound TNP was still linked to BSA, and the observation that phagocytic-depleted cells could interact with the soluble TNP-proteins and function as H-2-restricted targets, appear not to favor the first two proposed mechanisms.     

跟骨定量超声骨质测量参数与骨密度及骨组织形态计量学指标的关系

目的:分析跟骨定量超声骨质测量中各参数与骨密度及形态计量学指标的相关性。方法:选择2004-01/2005-12广州市第六人民医院和中山大学三院骨科小腿以上截肢患者38例,将其跟骨定量超声测定的超声振幅衰减平均值与健康青年人骨峰值进行比较,>-2.5 SD者为骨量正常组(12例),<-2.5 SD者为骨质疏松组(26例)。分别进行跟骨定量超声、双能X线骨密度测量仪及骨形态计量学测量,应用直线相关分析法分析跟骨定量超声测定中各参数与骨密度及骨组织形态计量学各指标的相关性。结果:38例全部进入结果分析。①骨质疏松组跟骨超声振幅衰减平均值和骨硬度指数值均小于骨量正常组(P<0.01)。②骨量正常组跟骨骨密度值显著高于骨质疏松组[(352±16),(233±14)mg/cm2,P<0.01]。③骨量正常组跟骨平均骨小梁间距或弥散度低于骨质疏松组而松质骨体积高于骨质疏松组(P<0.05)。④超声振幅衰减平均值和骨硬度指数与骨密度呈直线正相关(r=0.814,0.326,P<0.01,0.05)。⑤超声传播速度与骨小梁游离末端、平均骨小梁间距呈直线负相关(r=-0.688,-0.712,P<0.01),与小梁间连点数、松质骨体积呈直线正相关(r=0.672,0.794,P<0.01);骨硬度指数与平均骨小梁间距呈直线负相关(r=-0.358,P<0.05),与松质骨体积呈直线正相关(r=0.513,P<0.01)。结论:跟骨定量超声测量中,超声振幅衰减平均值能较好地反映骨的密度,超声传播速度能较好地反映骨的质量,而骨硬度指数能较综合地反映骨强度的改变。     

Patient-specific decision modeling to guide the use of drotrecogin α (activated) in patients with severe sepsis

Purpose

The expected benefit of treating severe sepsis with drotrecogin α (activated) for an individual patient may depend upon several clinical factors including disease severity. Our objective was to create a decision support tool incorporating patient-specific inputs to estimate the balance between treatment risks and benefits for individual patients with severe sepsis.

Materials and Methods

Logistic regression models were developed to calculate patient-specific mortality risk with and without treatment, which were then used as inputs into a 75-state Markov model. Patient-specific inputs included patient age, sex, and 12 readily available clinical characteristics.

Results

The expected benefit from drotrecogin α (activated) treatment was most dependent upon the underlying disease severity. For example, for a 56-year-old white man with severe sepsis and a 28-day mortality risk of 29%, the model predicted a treatment-related gain of 1.2 quality-adjusted life years (17.3 vs 16.1). Probabilistic sensitivity analyses demonstrated that this patient would benefit from therapy 85% of the time.

Conclusions

A customizable decision model using patient-specific inputs can be used to inform the treatment decision when considering the use of drotrecogin α (activated) therapy by weighing the risks vs the benefits of therapy in the treatment of severe sepsis.     

The Diurnal Variation of the Serum Iron Concentration

Observations made in an investigation of the diurnal variation of the serum iron concentration suggested that the diurnal variations of serum iron can be explained as a phenomenon secondary to the diurnal variation of the hemoglobin metabolism. This hypothesis is supported by parallel changes in the bilirubin and serum iron values.     

Self-limited blastomycosis: a report of thirteen cases

Blastomycosis is not generally recognized to be a self-limited pulmonary infection. We report 13 patients with blastomycosis who followed a self-limited course. Presenting complaints were usually those of an acute pulmonary infection with fever, productive cough, and pleurtiic chest pain. The duration of symtpoms before diagnosis was usuallms were variable and not diagnostic. The blastomycin skin test and complement-fixing serologies to blastomycin were generally not helpful. In all patients the diagnosis was made by either cultural or visual identification of the organism from sputum, bronchial washings, or pleural fluid. All patients were improving both clinically and by chest roentgenograms by the time the diagnosis was reached, and thus therapy was withheld. Follow-up of these 13 patients ranged from 5 months to 8 yr (mean, 43 months), and in no instance has there been any evidence of reactivation of the illness.