Which of the following conditions is characterized by the presence of multiple fluid-filled sacs within the ovaries and is associated with menstrual irregularities and hyperandrogenism?

Correct Answer: A

Rationale: Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. It is characterized by the presence of multiple fluid-filled sacs (cysts) within the ovaries, which can be visualized on ultrasound. Women with PCOS often experience menstrual irregularities such as irregular periods or no periods, as well as symptoms of hyperandrogenism like hirsutism (excessive hair growth) and acne. Other common features of PCOS include insulin resistance and obesity. It is important to note that not all women with PCOS will have ovarian cysts, but the presence of multiple cysts is a common finding in this condition.

Correct Answer: A

Rationale: Plasma cells are the primary type of cells responsible for the production of antibodies during the humoral immune response. When activated by antigens, B cells differentiate into plasma cells, which are specialized in producing large quantities of antibodies. These antibodies are essential in fighting off infections by binding to antigens and marking them for destruction by other immune cells. T helper cells assist in activating B cells, but the actual production of antibodies is mainly carried out by plasma cells. Memory B cells are involved in mounting a rapid and specific secondary response upon re-exposure to the same antigen. Macrophages play a role in phagocytosis and antigen presentation, but they are not the primary cells responsible for producing antibodies during the humoral immune response.

Correct Answer: A

Rationale: Selective IgA deficiency is a primary immunodeficiency disorder characterized by low or absent levels of immunoglobulin A (IgA) in the blood. Since IgA plays a crucial role in mucosal immunity and defense against pathogens at mucosal surfaces, individuals with this deficiency are more susceptible to recurrent bacterial infections, particularly of the respiratory and gastrointestinal tracts. In contrast, severe combined immunodeficiency (SCID) is a more severe immunodeficiency disorder affecting T and B lymphocytes, chronic granulomatous disease (CGD) is a disorder of phagocytes, and autoimmune hemolytic anemia is an autoimmune disease involving red blood cells, none of which are directly associated with selective IgA deficiency.

Correct Answer: B

Rationale: In a patient experiencing an acute asthma exacerbation with severe respiratory distress and hypoxemia, the most appropriate intervention is to initiate non-invasive positive pressure ventilation (NIPPV). NIPPV can help improve ventilation, decrease work of breathing, and correct hypoxemia by providing positive pressure to keep the airways open, reduce air trapping, and increase the elimination of carbon dioxide. This intervention can help improve oxygenation and reduce the need for invasive mechanical ventilation in patients with severe asthma exacerbations. Administering high-flow oxygen via nasal cannula alone may not provide enough support for patients with severe respiratory distress. Nebulized albuterol/ipratropium combination therapy and intravenous corticosteroid therapy are also important treatments for asthma exacerbations but are not the first-line interventions for patients with severe respiratory distress and hypoxemia.

Correct Answer: C

Rationale: In a pregnant patient with suspected pulmonary embolism (PE), the most appropriate imaging modality for evaluation is contrast-enhanced computed tomography (CT) pulmonary angiography. This imaging technique has been shown to be safe for the fetus when necessary, especially if the benefits of making a diagnosis outweigh the minimal risks associated with radiation exposure. It provides quick and accurate detection of PE with high sensitivity and specificity.