pediagenosis: Organ
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Showing posts with label Organ. Show all posts
Showing posts with label Organ. Show all posts

Wednesday, June 9, 2021

BASAL CELL NEVUS SYNDROME

BASAL CELL NEVUS SYNDROME

BASAL CELL NEVUS SYNDROME

BASAL CELL NEVUS SYNDROME


Basal cell nevus syndrome (BCNS), also known as nevoid basal cell carcinoma syndrome or Gorlin syndrome, is an uncommon autosomal dominant genodermatosis caused by mutations in the patched-1 (PTCH1) gene on chromosome 9. Approximately 40% of cases represent new, spontaneous mutations. Affected individuals are predisposed to the development of multiple basal cell carcinomas (BCCs), often in the hundreds over their lifetime. The diagnosis of this syndrome is based on a number of established criteria.

AMYLOIDOSIS

AMYLOIDOSIS

AMYLOIDOSIS

AMYLOIDOSIS


The term amyloidosis refers to a heterogeneous group of diseases. Systemic and cutaneous forms of amyloidosis can occur and are caused by the deposition of one of many different amyloid proteins. The primary cutaneous forms are more frequently seen. They include nodular, lichen, and macular amyloidosis (also referred to as lichen or macular amyloidosis). The systemic form is a multisystem, life-threatening disorder that requires systemic therapy. Most systemic disease is caused by an abnormality in plasma cells; myeloma-associated amyloid is a distant second in incidence. In addition to amyloidosis of the skin, the central nervous system may be involved with amyloidosis, as it is in Alzheimer’s disease.

ADDISON’S DISEASE

ADDISON’S DISEASE

ADDISON’S DISEASE

ADDISON’S DISEASE


Addison’s disease (chronic primary adrenocortical insufficiency) occurs when the adrenal gland has lost most of its functional capacity. Addison’s disease can be caused by many different disease states that inhibit the functioning of the adrenal gland. The adrenal gland has a massive reserve capacity, and clinical manifestations of chronic adrenal insufficiency are not seen until the bilateral glands have lost at least 90% of their ability to produce adrenal hormones. Autoimmune destructive atrophy of the adrenal glands is the most common cause of Addison’s disease. Infectious processes can cause destruction of the adrenal gland, with tuberculosis one of the more common causes of chronic adrenal gland insufficiency. Most cases of acute adrenal gland destruction are caused by bacteria (i.e., meningococcal disease).

WILSON’S DISEASE

WILSON’S DISEASE

WILSON’S DISEASE

WILSON’S DISEASE


Wilson’s disease, also known as hepatolenticular degeneration, is a disorder caused by a defect in copper metabolism. The disease is rare, with a worldwide incidence of approximately 1 in 18,000. It is an autosomal recessive condition that is caused by a defect in the ATP7B gene, which is located on the long arm of chromosome 13. The product of this gene is responsible for the proper transport of copper. The main clinical findings relate to nervous system involvement and liver disease. Wilson’s disease has a variable phenotype depending on the specific genetic mutation. Cutaneous disease and ophthalmological disease are frequently seen.

VITAMIN K DEFICIENCY AND VITAMIN K ANTAGONISTS

VITAMIN K DEFICIENCY AND VITAMIN K ANTAGONISTS

VITAMIN K DEFICIENCY AND VITAMIN K ANTAGONISTS

POTENTIAL CLINICAL CONSEQUENCES OF WARFARIN USE
POTENTIAL CLINICAL CONSEQUENCES OF WARFARIN USE


Vitamin K is an essential nutrient that is required as a cofactor for the production of a handful of coagulation cascade proteins. It is a fat-soluble vitamin that is efficiently stored in the human body. Vitamin K deficiency is rare and is typically seen only transiently in neonates and infants during the first 6 months of life. Affected neonates may show abnormally prolonged bleeding after minor trauma. Patients may have an elevated pro- thrombin time (PT) and decreased serum levels of vitamin K and coagulation factors. Therapy consists of replacement of vitamin K to normal levels and a search for any possible underlying cause, such as liver or gastrointestinal disease. Neonatal and infantile vitamin K deficiency is most likely caused by maternal breast milk insufficiency of vitamin K.

VITAMIN A DEFICIENCY

VITAMIN A DEFICIENCY

VITAMIN A DEFICIENCY

VITAMIN A DEFICIENCY


Vitamin A deficiency, also known as phrynoderma, is a multisystem disorder caused by a deficiency of vitamin A, either from lack of intake or from a decrease in normal absorption. Vitamin A is a fat-soluble essential vitamin that is stored in the fatty tissue and liver. Humans require a nutritional source for this vitamin. Foods high in vitamin A include all yellow vegetables (including carrots), green leafy vegetables, liver, milk, eggs, tomatoes, and fish oils. Many other food staples contain vitamin A. Hippocrates may have been the first to describe vitamin A deficiency and a therapy for it. However, it was not until the early twentieth century that scientists recognized the different forms of vitamin A and its carotene precursors.

Tuesday, June 8, 2021

INTRODUCTION OF CHEST DRAINAGE TUBES

INTRODUCTION OF CHEST DRAINAGE TUBES

INTRODUCTION OF CHEST DRAINAGE TUBES

INTRODUCTION OF CHEST DRAINAGE TUBES


Pleural drainage tubes are inserted for evacuation of air or fluid from the pleural space in diseases such as pneumothorax, hemothorax, and empyema.

Placement of an intercostal tube or catheter for pneumothorax can be readily accomplished under local anesthesia, with or without an intercostal nerve block. Chest tube placement may be done at the bedside, but strict aseptic precautions should be observed. The second or third anterior intercostal space in the midclavicular line or the fourth or fifth intercostal space in the midaxillary line are the preferred sites for chest tube placement. To help select the optimal point of entry, chest radiographs should be reviewed unless the clinical situation is one of extreme urgency.

OXYGEN THERAPY IN CHRONIC RESPIRATORY FAILURE (AMBULATORY AND HOME USE

OXYGEN THERAPY IN CHRONIC RESPIRATORY FAILURE (AMBULATORY AND HOME USE

OXYGEN THERAPY IN CHRONIC RESPIRATORY FAILURE (AMBULATORY AND HOME USE

OXYGEN THERAPY IN CHRONIC RESPIRATORY FAILURE (AMBULATORY AND HOME USE


Supplemental oxygen was the first treatment shown to improve survival in patients with chronic obstructive pulmonary disease (COPD). A multicenter clinical trial published in 1980 demonstrated the benefit of oxygen used continuously compared with oxygen only administered nocturnally. The current recommendations for oxygen therapy in patients with COPD are (1) partial pressure of oxygen in arterial blood (Pao2) of 55 mm Hg or below (or pulse oxygen saturation [Spo2]  88%) or (2) Pao2 of 56 to 60 mm Hg (Spo2, 89%) with erythrocytosis (hematocrit >56 mL/dL) or cor pulmonale. Because of the benefits of oxygen, reimbursement is available from most medical insurance payers. The long-term benefit of oxygen in patients with less severe hypoxemia is unknown.

METHODS OF OXYGEN ADMINISTRATION

METHODS OF OXYGEN ADMINISTRATION

METHODS OF OXYGEN ADMINISTRATION

METHODS OF OXYGEN ADMINISTRATION


Various types of oxygen delivery devices are available. With a flow rate of 6 to 10 L/min of 100% oxygen, it is possible to achieve inspired oxygen concentrations (Fio2) of up to 95%. The actual Fio2 depends on the system used and the oxygen flow rate relative to the patient’s respiratory rate and tidal volume.

OXYGEN THERAPY IN ACUTE RESPIRATORY FAILURE

OXYGEN THERAPY IN ACUTE RESPIRATORY FAILURE

OXYGEN THERAPY IN ACUTE RESPIRATORY FAILURE

OXYGEN THERAPY IN ACUTE RESPIRATORY FAILURE


ARTERIAL BLOOD GAS COMPOSITION

Arterial blood gas (ABG) findings can be explained by the carbon dioxide: oxygen diagram shown at the top of the illustration. Because there is no uptake or excretion of nitrogen during respiration and the alveolar partial pressure of water vapor is a function of body temperature only, there is a reciprocal relationship between the alveolar Pco2   and Po2, as indicated by the alveolar gas composition line.  Because prolonged survival is not possible when the PaO2    is less than 20 mm Hg, the range of arterial gas tensions compatible with life is confined to the yellow triangle. Initial ABG values of air-breathing patients with decompensated chronic obstructive pulmonary disease (COPD) fall in the upper shaded blue area. With higher oxygen concentrations, the alveolar gas composition line is shifted to the right, and much higher PaCO2 values are possible.

PULMONARY REHABILITATION

PULMONARY REHABILITATION

PULMONARY REHABILITATION

PULMONARY REHABILITATION


Pulmonary rehabilitation is an evidence-based, multi-disciplinary, and comprehensive intervention for patients with chronic respiratory diseases who are symptomatic and often have decreased daily life activities. Integrated into the individualized treatment of the patient, pulmonary rehabilitation is designed to reduce symptoms, optimize functional status, and reduce health care costs through stabilizing or reversing the manifestations of the disease.

PULMONARY PHARMACOLOGY

PULMONARY PHARMACOLOGY

PULMONARY PHARMACOLOGY

BRONCHODILATORS
BRONCHODILATORS


Pulmonary pharmacology concerns the effects of drugs on the lungs and understanding how drugs used to treat patients with pulmonary diseases work. Much of this pharmacology concerns drugs used to treat obstructive airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD).

Wednesday, June 2, 2021

Epithelial Barriers

Epithelial Barriers


Epithelial Barriers
Phagocytosis. (A) A phagocytic white blood cell moves through a capillary that is in an infected area and engulfs the bacteria. (B) The lysosome digests the bacteria that was in a vesicle
Physical, mechanical, and biochemical barriers against microbial invasion are found in all common portals of entry into the body, including the skin and respiratory, gastrointestinal, and urogenital tracts. The intact skin is by far the most formidable physical barrier available to infection because of its design. It is comprised of closely packed cells that are organized in multiple layers that are continuously shed. In addition, a protective layer of protein, known as keratin, covers the skin. The skin has simple chemicals that create a nonspecific, salty, acidic environment and antibacterial proteins, such as the enzyme lysozyme, that inhibit the colonization of microorganisms and aid in their destruction. The complexity of the skin becomes evident in cases of contact dermatitis where increased susceptibility to cutaneous infection occurs as the result of abnormalities of the innate immune response including defects in the epithelial layer itself and defects in both signaling and or expression of innate responses.
Into The Future: Immunology In The Age Of Genomics

Into The Future: Immunology In The Age Of Genomics


Into The Future: Immunology In The Age Of Genomics
The completion of the first complete DNA sequence of the human genome in 2003 was a landmark in the history of science. Remarkably, despite containing over 3 billion base pairs, the genome is believed to code for only around 20 000 genes, far fewer than most scientists had estimated. The function of much of the rest of the DNA remains unclear, although much of it is likely to be involved in regulating gene expression. An increasing number of genomes of other organisms (including of course the indispensable laboratory mouse) are already, or will be shortly be, available. Genome-wide comparisons between species are already providing fascinating new insights into the process of evolution. The next major phase of the genome project, to define the diversity of the DNA sequence within a species, is now under way. Current data suggest that the DNA sequences of any two humans differ from each other by an amazing 10 000 000 base pairs. The most common type of difference are called single nucleotide substitutions, or SNPs, (pronounced ‘snips’).

Into The Future: Immunology In The Age Of Genomics

All this information has had a major impact on immunology, allowing rapid discovery of many new molecules involved in the interaction between the host and the pathogen. The figure shows the 22 human autosomes, plus the X and Y chromosome, stained with a DNA dye that gives a characteristic banding pattern known as the ideogram. Each band is given a number (e.g. 14q32 means band 32 on the long arm of chromosome 14, p refers to the short arm) which unambiguously identifies that region of the chromosome. The figure illustrates in green the ideogram positions of the genes that code for some of the most important molecules making up the human immune system, all of which are discussed elsewhere in this book. One striking discovery, illustrated in this figure, is the extent to which the immune system is made up of multigene families, which have presumably arisen by multiple duplication events. Many immune genes are also polymorphic. The extent of immune gene duplication and polymorphism (far greater than in most non-immune genes) is testament to the enormous selective pressure exerted by the microbial world during our past evolutionary history. Mutations in several genes have been associated with (often very rare) diseases affecting the immune system. The list is not exclusive, as new examples are rapidly being discovered. You can find information about any other gene you may be interested in by searching at the American National Centre for Biotechnology Information.
Out Of The Past: Evolution Of Immune Mechanisms

Out Of The Past: Evolution Of Immune Mechanisms


Out Of The Past: Evolution Of Immune Mechanisms
From the humble amoeba searching for food (top left) to the mammal with its sophisticated humoral and cellular immune mechanisms (bottom right), all cellular organisms can discriminate between self and non-self, and have developed defence systems to prevent their cells and tissues being colonized by parasites.

Out Of The Past: Evolution Of Immune Mechanisms

This figure shows some of the important landmarks in the evolution of immunity. As most advances, once achieved, persist in subsequent species, they have for clarity been shown only where they are first thought to have appeared. It must be remembered that our knowledge of primitive animals is based largely on study of their modern descendants, all of whom evidently have immune systems adequate to their circumstances.

Sunday, May 30, 2021

MUSCLES OF UPPER ARM AND ELBOW

MUSCLES OF UPPER ARM AND ELBOW


MUSCLES OF UPPER ARM AND ELBOW
The arm, or brachium, is the region between the shoulder joint and the elbow. The arm muscles are few, and they are served by certain of the terminal branches of the brachial plexus and portions of the great vascular channels of the limb (see Plates 2-7 to 2-11).
MUSCLES OF UPPER ARM AND ELBOW, Brachial Fascia, Muscles, Coracobrachialis Muscle, Biceps Brachii Muscle, Brachialis Muscle, Triceps Brachii Muscle, Anconeus Muscle, Muscle Actions

Brachial Fascia
A strong tubular investment of the deeper parts of the arm, the brachial fascia is continuous above with the pectoral and axillary fasciae and with the fascial covering of the deltoid and latissimus dorsi muscles. Below, the brachial fascia is attached to the epicondyles of the humerus and to the olecranon and then is continuous with the antebrachial fascia. It is perforated for the passage of the basilic vein, for the medial antebrachial cutaneous nerve, and for many lesser nerves and vessels.

Saturday, May 29, 2021

The IgG Molecule

The IgG Molecule


The IgG Molecule
In IgG, the Fab arms are linked to the Fc by an extended region of polypeptide chain known as the hinge. This region tends to be exposed and sensitive to attack by proteases that cleave the molecule in to its distinct functional units arranged around the four‐chain structure (Milestone 3.1). This structure is repre­ sented in greater detail in Figure 3.2a. The light chains exist in two forms, known as kappa (k) and lambda (λ). In humans, k chains are somewhat more prevalent than λ; in mice, λ chains are rare. The heavy chains can also be grouped into different forms or subclasses, the number depending upon the species under consideration. In humans there are four subclasses hav­ ing heavy chains labeled γ1, γ2, γ3, and γ4, which give rise to the IgG1, IgG2, IgG3, and IgG4 subclasses. In mice, there are again four subclasses denoted IgG1, IgG2a, IgG2b, and IgG3. The subclasses – particularly in humans – have very similar primary sequences, the greatest differences being observed in the hinge region. The existence of subclasses is an important feature as they show marked differences in their ability to trigger effector functions. In a single molecule, the two heavy chains are generally identical, as are the two light chains. The exception to the rule is provided by human IgG4, which can exchange heavy–light pairs between IgG4 molecules to pro­ duce hybrids. As the Fc parts of the exchanging molecules are identical, the net effect is Fab arm exchange to generate IgG4 antibodies having two distinct Fab arms and dual specificity.
Linear representation, Domain representation, Domain nomenclature

The amino acid sequences of heavy and light chains of anti­bodies have revealed much about their structure and function. However, obtaining the sequences of antibodies is much more challenging than for many other proteins because the population of antibodies in an individual is so incredibly heterogeneous. The opportunity to do this first came from the study of myeloma proteins. In the human disease known as multiple myeloma, one cell making one particular individual antibody divides over and over again in the uncontrolled way a cancer cell does, without regard for the overall requirement of the host. The patient then possesses enormous numbers of identical cells derived as a clone from the original cell and they all synthesize the same immunoglobulin – the myeloma protein – which appears in the serum, sometimes in very high concentrations. By purification of myeloma proteins, preparations of a single antibody for sequencing and many other applications can be obtained. An alternative route to single or monoclonal antibodies arrived with the development of hybridoma technology. Here, fusing individual antibody‐forming cells with a B‐cell tumor produces a constantly dividing clone of cells dedicated to making the one antibody. Finally, recombinant antibody technologies, developed most recently, provide an excellent source of monoclonal antibodies.
The Structure and Function of The Immunoglobulin Classes

The Structure and Function of The Immunoglobulin Classes


The Structure and Function of The Immunoglobulin Classes
The immunoglobulin classes (Table 3.1) fulfill different roles in immune defense and this can be correlated with differences in their structures as organized around the four‐chain Ig domain arrangement (Figure 3.12). IgG is monomeric and the major antibody in serum and nonmucosal tissues, where it inactivates pathogens directly and through interaction with effector triggering molecules, such as complement and Fc receptors. IgM is pentameric, is found in serum, and is highly efficient at complement triggering. A monomeric form of IgM with a membrane‐tethering sequence is the major antibody receptor used by B‐lymphocytes to recognize antigen (see Figure 2.11). IgM differs from IgG in having an extra pair of constant domains instead of the hinge region. IgA exists in three soluble forms. Monomeric and small amounts of dimeric IgA (formed from two monomers linked by an extra polypeptide called J chain) are found in the serum where they can help link pathogens to effector cells via Fc receptors specific for IgA. Secretory IgA is formed of dimeric IgA and an extra protein known as secretory component (SC) and is crucial in protecting the mucosal surfaces of the body against attack by microorganisms. IgA exists as two subclasses in humans. IgA2 has a much shorter hinge than IgA1 and is more resistant to attack by bacterially secreted proteases. IgE is a monomeric antibody typically found at very low concentrations in serum. In fact, most IgE is probably bound to IgE Fc receptors on mast cells. Antigen binding to IgE crosslinks IgE Fc receptors and triggers an acute inflammatory reaction that can assist in immune defense. This can also lead to unwanted allergic symptoms for certain antigens (allergens). IgE, like IgM, has an extra pair of constant domains instead of the hinge region. Finally, IgD is an antibody primarily found on the surface of B‐cells as an antigen receptor together with IgM, where it likely serves in the control of lymphocyte activation and suppression. There is also some evidence that free IgD may help protect against microbes in the human upper respiratory tract. IgD is monomeric and has a long hinge region.
The structures of the Fc regions of human IgA1 and IgE have been determined and are compared with IgG1 in Figure 3.13. In all three cases, the penultimate domains are unpaired and have carbohydrate chains interposed between them.
Genetics of Antibody Diversity and Function

Genetics of Antibody Diversity and Function


Genetics of Antibody Diversity and Function
Antibody genes are produced by somatic recombination
The immunoglobulin repertoire is encoded for by multiple germline gene segments that undergo somatic diversification in developing B‐cells. Hence, although the basic components needed to generate an immunoglobulin repertoire are inherited, an individual’s mature antibody repertoire is essentially formed during their lifetime by alteration of the inherited germline genes. The first evidence that immunoglobulin genes rearrange by somatic recombination was reported by Hozumi and Tonegawa in 1976 (Milestone 3.2). Because somatic recombination involves rearrangement of DNA in somatic rather than gamete cells, the newly recombined genes are not inherited. As a result, the primary immunoglobulin repertoire will differ slightly from one individual to the next, and will be further modified during an individual’s lifetime by their exposure to different antigens.

Milestone 3.2 The 1987 Nobel Prize in Physiology or Medicine
Susumu Tonegawa was awarded the 1987 Nobel Prize in Physiology or Medicine for “his discovery of the genetic principle for generation of antibody diversity.” In his 1976 paper, Tonegawa used Southern blot analysis of restriction enzyme digested DNA from lymphoid and nonlymphoid cells to show that the immunoglobulin variable and constant genes are distant from each other in the germline genome. Embryo DNA showed two components when hybridized to RNA probes specific for: (i) both variable and constant regions and (ii) only the constant region, whereas both probes localized to a single band when hybridized to DNA from an antibody‐ producing plasmacytoma cell. He proposed that the differential hybridization patterns could be explained if the variable and constant genes were distant from each other in germline DNA, but came together to encode the complete immunoglobulin gene during lymphocyte differentiation.


Figure 3.20 The human immunoglobulin loci. Schematics of the human heavy chain (top) and light chain lambda (middle) and kappa (bottom) loci are shown. The human heavy chain locus on chromosome 14 consists of approximately 40 functional VH genes, 23 DH genes, and 6 JH genes, which are organized into clusters upstream of the constant regions. The human lambda locus on chromosome 22 consists of approximately 30 functional Vλ genes and 5 functional Jλ gene segments, with each J segment followed by a constant segment. The human kappa locus on chromosome 2 consists of about 40 functional Vκ genes and 5 functional Jκ genes, with the J segments clustered upstream of the constant region. L, leader sequence.

The immunoglobulin variable gene segments and loci
The variable light and heavy chain loci in humans contain multiple gene segments, which are joined, using somatic recombination, to produce the final V region exon. The human heavy chain variable region is constructed from the joining of three gene segments, V (variable), D (diversity), and J (joining), whereas the light chain variable gene is constructed by the joining of two gene segments, V and J. There are multiple V, D, and J segments at the heavy chain and light chain loci, as illustrated in Figure 3.20.

Wednesday, May 26, 2021

DERMATOFIBROSARCOMA PROTUBERANS

DERMATOFIBROSARCOMA PROTUBERANS


DERMATOFIBROSARCOMA PROTUBERANS
Dermatofibrosarcoma protuberans is a rare cutaneous malignancy that is locally aggressive. The tumor is derived from the dermal fibroblast, and it is not believed to arise from previously existing dermatofibromas. Dermatofibrosarcoma protuberans rarely metastasizes, but it has a distinctive tendency to recur locally.
DERMATOFIBROSARCOMA PROTUBERANS

Clinical Findings: Dermatofibrosarcoma protuberans is a slow-growing, locally aggressive malignancy of the skin. These tumors are low-grade sarcomas and make up approximately 1% of all soft tissue sarcomas. The tumor is found equally in all races and affects males slightly more often than females. Most tumors grow so slowly that the patient is not aware of their presence for many years. The tumor starts off as a slight, fleshcolored thickness to the skin. Over time, the tumor enlarges and has a pink to slightly red coloration. It slowly infiltrates the surrounding tissue, particularly the subcutaneous tissue. If the tumor is allowed to grow long enough, the malignancy will grow into the fat and then back upward in the skin to develop satellite nodules surrounding the original plaque. This is often the reason a patient seeks medical care. The tumor tends to grow slowly for years, but it can hit a phase of rapid growth. This rapid growth phase allows the tumor to grow in a vertical direction, and hence the term protuberans is applied. If medical care is not undertaken, the tumor will to continue to invade the deeper structures, eventually invading underlying tissue, including fascia, muscle, and bone.

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