## Solving Statistics: Overpowered multivariable linear regression?

Overpowered multivariable linear regression?

## Question

In order to identify parameters that influence myocardial perfusion, a total of 70 patients were included in a multivariable linear regression model. A total of 19 different predictors were considered, of which 18 were measured on patient level (for example gender, age, BMI, smoking, medication, blood pressure) and 1 on coronary artery level (diameter of the coronary artery at stenosis).

## Clinical Image: A 14-year-old girl

A 14-year-old girl

[headline_subtitle subtitle=”Can you come up with the proper diagnosis?”]
##### Presentation

At the outpatient a 14-year old girl is seen with progressive blue-purple discolorization of her feet. Walking was painful. Upon physical examination discolorization is noted of her toes and the front parts of her feet. There were some blisters on her toes.

## SkillsLab: Determining benign from malign

Determining benign from malign

Why is it important to distinguish between seborrheic keratosis and basal cell carcinoma in clinical setting? After watching this SkillsLab video you will be able to properly diagnose a patient and distinguish between seborrheic keratosis and basal cell carcinoma.

## Radiology Image: A 32-year-old male

A 32-year-old male

##### Patient data
• Age: 32
• Gender: Male
• Medical history: None
• Initial presentation: Heavy bar landed on patients’ back, after which the patient fell on the floor and hit his head.
• Examination: Head injury and lumbal swelling. Pain at thoracic spine. Decreased sphincter tension. Tingling sensation was present in both legs after the accident, but had already disappeared at time of examination.
• Examination: Normal auscultation and normal percusion

## Interview: prof. dr. P. Wesseling

prof. dr. P. Wesseling

Some MD’s already know in their infancy what they would like to become (pediatrician!; brain surgeon!) and manage to make that dream come true. However the road to my ‘final destination’ in Medicine was quite different. After finishing highschool I had figured out that I wanted to become a dentist. I assumed that this would allow me to combine intellectual challenges with workmanship (sic!). Nevertheless a few weeks into the first lectures in dentistry (UvA, 1977) I started to doubt whether dentistry was really the right choice for me.

## Trial and Error: Catching a virus

Catching a virus

At the Tytgat Insitute for Liver and Intestinal research, next to the AMC main building, PhD students are passionately trying to make their first scientific mark on their respective fields of study. To study human diseases many of these researchers rely on intricate mouse-models, which can provide important insights on pathophysiological mechanisms or novel treatments. These precious and valuable mice can be very challenging to breed and, as you can imagine, are carefully kept in a clean facility. Despite these precautions, this facility recently was infected with a very virulent mouse hepatitis virus. Understandably, when this was discovered all researchers who were in the middle of their experiments were fearful of having to throw away their data. As we speak, their mice are being tested whether they really are infected or not, a time-consuming process. Furthermore, the whole facility must be cleared out, meaning that most mice must be sacrificed. For many researchers, this means starting over and breeding their mice of interest all over again..

Although very misfortunate, this event offers us an important lesson. In scientific research, a proper back-up of the data on your computer is not sufficient to prevent the setbacks of a virus-infection. It is also crucial to cryopreserve embryos or sperm of your valuable genetically modified mouse strain. Since not only computers can catch a dangerous virus, mice can as well

## Changing Perspectives: Bed rest

Bed rest

The lumbosacral radicular syndrome is associated with radiating pain in one or more lumbar or sacral dermatomes. Patients are treated mostly with conservative treatment first and for decades the mainstay of this conservative treatment was strict bed rest for 14 days. Clinical trials back in the 90’s already showed that bed rest in patients with a lumbosacral radicular syndrome is not more effective than ‘watchful waiting’ and ‘watchful exercise’.

## Subject 101: C-reactive protein after major abdominal surgery: biochemical and clinical aspects

C-reactive protein after major abdominal surgery: biochemical and clinical aspects

## Abstract

C-reactive protein (CRP) is an established marker for non-specific acute phase response to most forms of inflammation, which may be caused by infection or tissue damage, such as occurs in surgery. CRP is produced in the liver. In surgical patients, tissue damage is the main stimulus for CRP synthesis, and levels are independent of diurnal rhythm, diet or medication. These properties underscore the suitability of CRP as a marker for postoperative inflammation. CRP is non-specific to location of tissue damage or cause, indicating additional examinations are necessary in patients with elevated CRP levels in the postoperative phase. The aim of this study was to review the literature concerning biochemical and clinical aspects of CRP in relation to major abdominal surgery.