Archive for the ‘Medicine’ Category

Women Are More Complex—Genetically

There are things that I will never understand like misogyny, rape, and abuse. I am a straight dominant man. I cannot look at a woman and not be amazed at the beauty of her form, the strength of her mind, and the mysteries within her eyes. There is a beauty in every woman and only the right man brings it shining out. If a woman is not interested in you, she is not a slut or bitch; she is simply not for you. A confident man with nothing to prove merely wishes her a goodnight, tells her that she is still beautiful in his eyes and goes on his way to look for the right one for him. If you are a straight male and you don’t love and respect a woman, the problem is not with them, it is with you. Respect is never weak. Respect amplifies everything that is inside. So, good becomes great. Bad becomes worse, a strong man, who has known power all his life, will lose respect for that power. But a weak man knows the value of strength, and knows compassion. Women are genetically more complex because the active X chromosome is a mix of mom’s and dad’s. Men’s X chromosome all comes from mom and their Y chromosome carries less than 100 genes, compared with about 1,500 for the X chromosome.

Although women may not be scientifically proven to differ from men in intelligence or motivation, researchers have discovered women are more complex—genetically, at least. In a study published in Nature, researchers from Duke and Pennsylvania State University found surprising levels of genetic variation on the X chromosome—an area that has not been fully explored until now. The findings suggest women and men are more different than originally believed. When considering this additional number of genes as well as the variability in gene expression on the X chromosome, women are more complex than men, in that sense.

The human genome, the complete set of genes within an individual, is comprised of 23 pairs of chromosomes, one pair of which is responsible for determining gender. These two chromosomes, called sex chromosomes, are designated by the letters X and Y. Males have a combination of X and Y, while females have two X chromosomes. Genes, a DNA sequence that encodes the recipe to create proteins in the body, are located on chromosomes. Because women have two sets of X genes, female cells choose to de-activate one copy of the X chromosome in a process called “silencing.” This is to avoid any harmful effects that would result in double expression of such genes.

At least 15 percent of the genes on the X chromosome escape silencing and another 10 percent show variable degrees of expression among women. The results of the study, however, not only revealed the degree of genetic differences between the sexes, they also showed differences among women themselves. While one woman may have her copy of a particular X-linked gene expressed, another woman may not. These un-silenced or partially silenced genes on the X chromosome comprise more than 1 percent of the entire genome, accounting for more than 200 to 300 more expressed genes in women than in men. What the finding superimposes upon the characteristic differences between men and women is how much of that variation is present from one female to another.

Recognizing this variation is important for medicine, as there are a large number of diseases that are much more common among women than men. A lot of the differences in gender-based medicine are due to hormonal effects and cultural effects. We should look in addition at the genetic differences between men and women. There are still many basic questions to be answered, such as whether this variability in silencing is affected by age or is present in different tissues. The ultimate goal is to provide information to help identify patients who have the highest risks for sex-associated diseases and guide treatment. These diseases, which range from heart disease to psychiatric disorders, involve numerous genes that are found on other chromosomes in addition to the X.

Researchers went into this from a very basic perspective to understand the basis of silencing events, but now they are finding very important results that have medical implications such as genetic counseling for hereditary diseases. In the case of Turner’s syndrome, in which only one of the two X chromosomes is functional in a female, deficits in the genes responsible for the symptoms can now be clarified, providing scientists with a better understanding of the biology underlying the genetic disease. We can never answer all the questions; we can just ask better questions.


How to Handle Belch?

Belching is the act of bringing up air from the stomach. It produces a characteristic sound. Belching is most often a normal process. The purpose of belching is to release air from the stomach. Every time you swallow, you also swallow air, along with fluid or food. As the air builds up in the upper stomach, it causes stretching of the stomach that triggers the lower esophageal sphincter muscle to relax. This lets air escape up the esophagus and out the mouth. Excessive or repeated belching may be caused by unconsciously swallowing air what is medically called aerophagia. Depending on the cause, belching may change in duration and intensity. Symptoms such as nausea, dyspepsia, and heartburn may be relieved by belching.

Belching is caused by the pressure caused by the unconscious swallowing of air and or gastroesophageal reflux disease.

One could get relief by lying on side or in a knee-to-chest position until the gas passes. Avoid chewing gum, eating quickly, and eating gas-producing foods and beverages. If one has gastroesophageal reflux disease; learning to manage the symptoms of gastroesophageal reflux disease will alleviates belch. Belching is usually a minor symptom. However, calling a health care provider is warranted if the belching does not go away, or if one also has other symptoms.

The health care provider will examine and ask questions about medical history and symptoms, including but not limited to whether it is the first time this has occurred? Is there a pattern to belching? For example, does it happen when one is nervous or after one has been consuming certain foods or drinks? What other symptoms does one have? The Diagnostic tests depend on the findings of the physical examination, and other signs or symptoms one has with the belching.

Other alternative names for belching include burping, eructation or gas.

Imaging No Help in Gallbladder Surgery Risk

In an analysis of a procedure used to help prevent common duct injury during gallbladder removal surgery, use of radiologic examination of the ducts during gallbladder surgery was not associated with a reduced risk of common duct injury, according to a study in the August 28 issue of JAMA.

Biliary anatomy misidentification during gallbladder removal can result in injury to the common hepatic duct or common bile duct. Common duct injuries cause significant short and long-term morbidity including major operations, multiple hospitalizations, and biliary strictures. Elimination of common duct injury is desirable, but it has remained stubbornly present with rates ranging from 0.3 percent to 0.5 percent, according to information. When routinely used, intra-operative cholangiography is thought to prevent common duct injury. However, controversy exists regarding the effectiveness of routine use in the prevention of common duct injury.

Kristin M. Sheffield, Ph.D., and Taylor S. Riall, M.D., Ph.D., of the University of Texas Medical Branch, Galveston, and colleagues investigated the association between intraoperative cholangiography use during cholecystectomy and common duct injury, using instrumental variable analysis, an effective way to overcome unmeasured confounding, that is to say, factors influencing outcomes not found in the database. The researchers identified Medicare beneficiaries from Texas Medicare claims data who underwent inpatient or outpatient cholecystectomy for conditions including biliary colic or biliary dyskinesia, acute cholecystitis, or chronic cholecystitis. The percentage of intraoperative cholangiography use at the hospital and by surgeon was the instrumental variables. Patients with claims for common duct repair operations within 1 year of cholecystectomy were considered as having major common duct injury.

In a logistic regression model controlling for patient, surgeon, and hospital characteristics, the odds of common duct injury for cholecystectomies performed without intraoperative cholangiography were increased compared with those performed with it. When confounding was controlled with instrumental variable analysis, the association between cholecystectomy performed without intraoperative cholangiography and duct injury was no longer significant.

Significant controversy exists regarding the role of intraoperative cholangiography in the prevention of common duct injury during cholecystectomy. Previous population-based studies using data from Medicare claims, hospital discharge records, and national inpatient registries report nearly 2-fold higher rates of injury in cholecystectomies performed without intraoperative cholangiography. In the present study using Texas Medicare claims data, the association between intraoperative cholangiography and common duct injury was highly sensitive to the analytic method used.

Failure to account for potentially confounding variables not routinely captured in administrative databases has a major effect on the interpretation of the findings. Intraoperative cholangiography was not associated with significant reduction in common duct injury using instrumental variable analysis. Instrumental variable analysis balances unmeasured confounding variables to better align risk factors in comparator groups. With better control for unmeasured confounding variables, intraoperative cholangiography was no longer associated with common duct injury. Based on these results, routine intraoperative cholangiography should not be advocated as means for preventing common duct injury.

While this report does not definitively close the door on routine intraoperative cholangiography use, use of directed attention to an important clinical debate by using a new approach to revisit the outcomes of intraoperative cholangiography using observational data. While the true effect of intraoperative cholangiography on the safety of laparoscopic cholecystectomy remains controversial, this study undoubtedly reinvigorates the discussion.

Fascinating Story of Getting Energy from Food We Eat!

The proteins, lipids, and polysaccharides that make up most of the food we eat must be broken down into smaller molecules before our cells can use them either as a source of energy or as building blocks for other molecules. The breakdown processes must act on food taken in from outside, but not on the macromolecules inside our own cells. The enzymatic breakdown of food molecules is therefore digestion, which occurs either in our intestine outside cells, or in a specialized organelle within cells; the lysosome. A membrane that surrounds the lysosome keeps its digestive enzymes separated from the cytosol. In either case, the large polymeric molecules in food are broken down during digestion into their monomer subunits—proteins into amino acids, polysaccharides into sugars, and fats into fatty acids and glycerol through the action of enzymes. After digestion, the small organic molecules derived from food enter the cytosol of the cell, where their gradual oxidation begins. Oxidation occurs in two further stages of cellular catabolism. Stage 2 starts in the cytosol and ends in the major energy-converting organelle, the mitochondrion; stage 3 is entirely confined to the mitochondrion.

In stage 2 a chain of reactions called glycolysis converts each molecule of glucose into two smaller molecules of pyruvate. Sugars other than glucose are similarly converted to pyruvate after their conversion to one of the sugar intermediates in this glycolytic pathway. During pyruvate formation, two types of activated carrier molecules are produced; adenosine-5′-triphosphate and nicotinamide adenine dinucleotide. The pyruvate then passes from the cytosol into mitochondria. There, each pyruvate molecule is converted into carbon dioxide plus a two-carbon acetyl group; which becomes attached to coenzyme A, forming acetyl coenzyme A, another activated carrier molecule. Large amounts of acetyl coenzyme A are also produced by the stepwise breakdown and oxidation of fatty acids derived from fats, which are carried in the bloodstream, imported into cells as fatty acids, and then moved into mitochondria for acetyl coenzyme A production.

Stage 3 of the oxidative breakdown of food molecules takes place entirely in mitochondria. The acetyl group in acetyl coenzyme A is linked to coenzyme A through a high-energy linkage, and it is therefore easily transferable to other molecules. After its transfer to the four-carbon molecule oxaloacetate, the acetyl group enters a series of reactions called the citric acid cycle. The acetyl group is oxidized to carbon dioxide in these reactions, and large amounts of the electron carrier nicotinamide adenine dinucleotide are generated. Finally, the high-energy electrons from nicotinamide adenine dinucleotide are passed along an electron-transport chain within the mitochondrial inner membrane, where the energy released by their transfer is used to drive a process that produces adenosine-5′-triphosphate and consumes molecular oxygen. It is in these final steps that most of the energy released by oxidation is harnessed to produce most of the cell’s adenosine-5′-triphosphate.

Because the energy to drive adenosine-5′-triphosphate synthesis in mitochondria ultimately derives from the oxidative breakdown of food molecules, the phosphorylation of adenosine diphosphate to form adenosine-5′-triphosphate that is driven by electron transport in the mitochondrion is known as oxidative phosphorylation. Fascinating events occur within the mitochondrial inner membrane during oxidative phosphorylation. Through the production of adenosine-5′-triphosphate, the energy derived from the breakdown of sugars and fats is redistributed as packets of chemical energy in a form convenient for use elsewhere in the cell. Roughly, 109 molecules of adenosine-5′-triphosphate are in solution in a typical cell at any instant, and in many cells, all this adenosine-5′-triphosphate is turned over, that is, used up and replaced every 1–2 minutes.

In all, nearly half of the energy that could in theory be derived from the oxidation of glucose or fatty acids to water and carbon dioxide is captured and used to drive the energetically unfavorable reaction orthophosphate plus adenosine diphosphate giving adenosine-5′-triphosphate. By contrast, a typical combustion engine, such as a car engine, can convert no more than 20% of the available energy in its fuel into useful work. The rest of the energy is released by the cell as heat, making our bodies warm.

Getting an Hour More of Sleep Per Night May Help Obese Adolescents Shed Pounds

Reduced sleep is linked with increase in body mass index in adolescents aged 14-18 years, particularly in heavier adolescents, according to a new study. Those who sleep an extra hour or more a night could lower their body mass index and so prevent overweight and obesity.

Physical inactivity and increased caloric intake explains the connection between short sleep and adolescent obesity. Short sleepers could be more exhausted during the daytime and spend less time being physically active. It is possible that short sleep add to total caloric intake due to more eating opportunities.

Short sleep affects hormones that regulate appetite and energy homeostasis. Such hormonal changes explain why there is an association between short sleep and adolescent obesity. An extra hour of sleep is associated with only a slight reduction in BMI at the 10th percentile. In comparison, greater reductions in BMI are observed at the 50th and 90th percentiles.

Increasing sleep from 8 to 10 hours per day at age 18 years result in a 4% reduction in the number of adolescents with a BMI higher than 25 kilograms per meter squared. The relationship between disturbed circadian rhythms and weight gain is well documented in animal models. However, it is not known if these findings in animals translate to humans, and thus more research is desirable to determine if staying awake at night and eating at night is associated with adolescent obesity.

Primary care physicians should advise adolescent patients to adopt good sleep hygiene practices, such as establish routine bed and wake times each day, associate the bedroom with sleep and not television viewing, and increase physical activity during the daytime.

Primary care physicians and other health care professionals could lend their support to changes in policies that would help support longer sleep duration among adolescents, for example, later high school start times and more physical education classes to increase daytime physical activity.

Achieving sufficient sleep needs should center on healthier eating, being more physically active, and creditability to the significance of sufficient sleep duration.

Credits: Dr Mitchell.


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