HCl


Also found in: Dictionary, Thesaurus, Acronyms, Encyclopedia, Wikipedia.

hydrochloric acid

 [hi″dro-klor´ik]
HCl, a normal constituent of gastric juice in humans and other animals. The absence of free hydrochloric acid in the stomach, called achlorhydria or gastric anacidity, may be found with chronic gastritis, gastric carcinoma, pernicious anemia, pellagra, and alcoholism.

HCl

Abbreviation for hydrochloric acid.

HCl

1 formula for hydrochloric acid.
2 formula for hydrogen chloride.

HCl

Abbreviation for hydrochloric acid.

leukemia

, leucemia (loo-ke'me-a) [ leuko- + -emia]
Any of a class of hematological malignancies of bone marrow cells in which immortal clones of immature blood cells multiply at the expense of normal blood cells. As normal blood cells are depleted from the body, anemia, infection, hemorrhage, or death result. The leukemias are categorized as chronic or acute; by the cell type from which they originate; and by the genetic, chromosomal, or growth factor aberration present in the malignant cells.

Chronic leukemias, which have a relatively slow course, include chronic lymphocytic (CLL), chronic myelogenous or granulocytic (CML), and hairy cell leukemia (a subtype of CLL). Median survival in these illnesses is about 4 yr.

Acute leukemias include acute lymphocytic (ALL) and acute myeloid (myelogenous) (AML) leukemia. If untreated, these diseases are fatal within weeks or months. Each of these types of leukemia is discussed in subentries, below.

Etiology

All the different molecular events leading to the development of unchecked cellular reproduction in the leukemias result from genetic or chromosomal lesions in blood-forming cells. Duplications of genetic material (hyperdiploidy), loss of genetic information (hypodiploidy), inactivation of genes that normally suppress tumor development, chromosomal translocations, and the release of abnormal fusion proteins can all cause leukemia. These genetic lesions in turn can be produced by viruses, ionizing radiation, chemotherapeutic drugs, and toxic chemicals. Rarely, leukemias are caused by familial genetic syndromes (e.g., as ataxia telangiectasia, Bloom's syndrome, or Fanconi's syndrome).

Symptoms

Clinical findings such as anemia, fatigue, lethargy, fever, and bone and joint pain may be present. Physical findings include combinations of pallor, petechiae, or purpura; mucous membrane bleeding; enlarged liver, spleen, and kidneys; and tenderness over the sternum and other bones.

Diagnosis

Microscopic examination of peripheral blood and specimens of bone marrow are used to establish the diagnosis. These studies are followed by cytochemical and cytogenetic studies of abnormal cells found in the marrow or the peripheral blood to confirm the diagnosis with special stains and chromosomal analysis. Leukemic cells can also be identified by flow cytometry and immunocytochemistry, which rely on antibodies binding to and helping to identify malignant cells. The spread of leukemias to internal organs (e.g., the brain, the kidneys, or the lungs) may be evaluated with imaging tests (e.g., MRI studies, CT scans, or ultrasound).

Treatment

Chemotherapy, bone marrow transplantation, or both are used to treat leukemias. Regimens are devised regularly and are tailored to specific illnesses. Treatment is often given in several phases, with a period of induction chemotherapy to induce remission by completely eliminating leukemic cells from the bone marrow, followed by consolidation and maintenance phases. This multiphase treatment is designed to further deplete malignant cells from the bone marrow and to achieve complete cure.

Patient care

Patient care measures focus on eradicating the illness; managing complications; minimizing the effects of chemotherapy; preserving veins (often an indwelling port is inserted to administer chemotherapy); and providing comfort, education, and psychological support. The specific needs of patients (many of whom are children) and their families must be considered. Instruction is provided about drugs the patient will receive, including any adverse reactions and measures that will be taken to prevent or alleviate these effects. Prescribed chemotherapy is administered with special precautions when indicated for infusion and drug disposal. If the chemotherapy causes weight loss or anorexia, nutritional guidance is provided. Oral, skin, and rectal care must be meticulous, e.g., the nurse must thoroughly clean the skin before all invasive procedures, inspect the patient for perirectal erosions, use strict aseptic technique when starting an intravenous line, and change sets (i.e., intravenous tubing and associated equipment) according to chemotherapeutic protocols. Ports are irrigated according to agency protocol. If the patient is receiving intrathecal chemotherapy, the lumbar puncture site is checked frequently for bleeding or oozing. The patient and family are taught to recognize signs of infection (fevers, chills, sore throat, cough, urinary difficulties) and are urged to report these to the oncologist/hematologist promptly. To prevent infection in neutropenic patients, strict hand hygiene protocols, special diets, and (in hospitalized patients) laminar airflow or other reverse isolation measures are instituted. The patient is monitored for bleeding. If bleeding occurs, compresses are applied and the bleeding site is elevated. Transfusions of platelets and other blood cells are often needed. Complications associated with specific chemotherapeutic regimens (e.g., hair loss, nausea and vomiting, anemia, neutropenia, and low platelets) are explained to the patient, along with management strategies that will be employed. Prescribed analgesics are administered as needed, and noninvasive pain relief techniques and comfort measures (e.g., position changes, cutaneous stimulation, distraction, relaxation breathing, and imagery) may be used. Gentle oral hygiene measures and protective skin care are explained. Fluid intake should be increased to eliminate chemotherapy metabolites, and the patient advised to void more frequently to prevent cystitis. Dietary fiber is important, and stool softeners may be used to ensure normal bowel movements. Antidiarrheals usually control diarrhea, but the patient should be monitored for signs of dehydration. Fatigue is an anticipated adverse effect of treatment; therefore the patient is encouraged to alternate activity with rest periods and to obtain assistance with daily activities as necessary. Reproductive issues should be discussed with the patient. Patient care routines and visiting times should be flexible when hospitalization is required. The patient and family are encouraged to participate in care as much as possible. Referrals are made to social service agencies, home health care agencies, and support groups. If the patient does not respond to treatment and has reached the terminal phase of the disease, supportive nursing, palliative care, or hospice care should be discussed sensitively with patients and their caregivers.

acute lymphoblastic leukemia

Acute lymphocytic leukemia.
Enlarge picture
ACUTE LYMPHOCYTIC LEUKEMIA: Peripheral blood smear

acute lymphocytic leukemia

Abbreviation: ALL
A hematological malignancy marked by the unchecked multiplication of immature lymphoid cells in the bone marrow, blood, and body tissues. In 2008 the American Cancer Society estimated about 5400 Americans would be diagnosed with ALL. It is rapidly fatal if left untreated. Synonym: acute lymphoblastic l. See: illustration; leukemia

Etiology

Any of a wide range of acquired or congenital chromosomal abnormalities can cause ALL, including lesions that result in the release of excess growth factors from cells and those that cause the loss of cancer-suppressing genes.

Symptoms

Fatigue, lethargy, bleeding, bone and joint pain, and a predisposition to fever and infection are characteristic of ALL and other leukemias.

Diagnosis

The disease is suggested by the presence of abnormalities on the complete blood count or peripheral blood smear and is confirmed by immunophenotyping.

Treatment

In childhood, ALL induction chemotherapy often begins with steroids, vinca alkaloids, and asparaginase. This is followed, after bone marrow recovery, by consolidation chemotherapy with multidrug regimens, including high-dose methotrexate. Maintenance therapies, which may last 2 years or longer, include methotrexate, mercaptopurines, and other cytotoxic agents. Prophylaxis against central nervous system disease is accomplished by intrathecal drug administration. In referral hospitals, allogeneic stem cell transplantation is sometimes used for refractory disease. About 90% of treated children achieve remission. The 5-year survival of children with ALL is about 85%. Adult ALL is much less responsive to therapy; only about a third of adult patients are cured. In both childhood and adult ALL, allopurinol and hydration precede induction chemotherapy to prevent hyperuricemia caused by tumor lysis.

Prognosis

Late complications of therapy are not uncommon.

acute myelogenous leukemia

Abbreviation: AML
Acute myeloid leukemia.

acute myeloid leukemia

Abbreviation: AML
Any of a group of hematological malignancies in which neoplastic cells develop from myeloid, monocytic, erythrocytic, or megakaryocytic precursors. AML is four times more common in adults than acute lymphocytic leukemia (ALL). In 2008, the American Cancer Society estimated about 13,300 Americans would be diagnosed with AML, and that the disease would cause 8,800 deaths. It occasionally follows a myelodysplastic disorder or aplastic anemia and sometimes occurs as a consequence of a familial disorder of fragile chromosomes (e.g., Fanconi's syndrome).

All forms of AML are marked by neoplastic replacement of normal bone marrow and circulation of immature cells (“blasts”) in the peripheral blood. Anemia and thrombocytopenia commonly occur. The central nervous system and other organs are occasionally invaded. Complete remissions occur in approximately 65% of treated patients; responses to treatment lasting 5 years are achieved in 15% to 25% of treated patients. Synonym: acute myelogenous l.; acute nonlymphocytic l.

Etiology

Genetic and chromosomal aberrations, such as are found in other leukemias, are characteristic.

Symptoms

Exertional fatigue as a result of anemia, bleeding due to thrombocytopenia, and infections due to a lack of normal white blood cells are common.

Treatment

Cytotoxic chemotherapies, with an induction phase followed by consolidation, are used. Typically, cytosine arabinoside and an anthracycline are used during induction for AML. Allogeneic bone marrow transplantation is used when a matching donor is available; stem cell transplantation is an option for some patients with specific cytogenetic abnormalities.

acute nonlymphocytic leukemia

Abbreviation: ANLL
Acute myeloid leukemia.

aleukemic leukemia

Leukemia cutis.
Enlarge picture
CHRONIC LYMPHOCYTIC LEUKEMIA: Peripheral blood smear

chronic lymphocytic leukemia

Abbreviation: CLL
A malignancy in which abnormal lymphocytes (usually B cells) proliferate and infiltrate body tissues, often causing lymph node enlargement and immune dysfunction. Infectious complications are common. Median life expectancy is about 4 years. Chronic lymphocytic leukemia is the most common leukemia in industrialized nations. It usually occurs in people (older men) above age 60. Its incidence rises to 20 cases per 100,000 in people over 80. In 2008 the American Cancer Society estimated that 15,100 people would be diagnosed with CLL and that 4,400 would die of the disease. The timing of treatment and the prognosis in CLL depend on the stage of the disease. Staging includes such factors as the number of abnormal lymphocytes in the bloodstream, how quickly they double, and the presence of lymphadenopathy, organomegaly, or cytopenias. See: illustration

Treatment

Patients with advanced stages of the illness are often treated with chlorambucil, fludarabine, or other cytotoxic agents, often with rituximab (a monoclonal antibody) added to enhance response. Patients with early-stage disease are not usually given therapy.

chronic myelogenous leukemia

Abbreviation: CML
Chronic myeloid leukemia.

chronic myeloid leukemia

Abbreviation: CML
A hematological malignancy marked by a sustained increase in the number of granulocytes, splenic enlargement, and a specific cytogenetic anomaly (the “Philadelphia chromosome”) in the bone marrow of more than 90% of patients. The disease affects one or two people per 100,000. In 2008 the American Cancer Society estimated that 4830 people would be diagnosed with CML and that 450 would die of the disease. The course of the disease has three phases: a chronic one in which blood counts are relatively easy to control with medications; an accelerated phase in which granulocyte counts become more resistant to chemotherapy; and a “blast” crisis, which resembles acute leukemia. Median survival is about 4 years. It generally occurs between ages 40 and 50, affecting slightly more men than women (4600 adults in the U.S. in 2005). Synonym: chronic myelogenous l See: leukemia

Etiology

CML results from a translocation of genetic material between chromosomes 9 and 22. The translocation results in the production of an abnormal tyrosine kinase that makes affected cells immortal.

Symptoms

CML often is diagnosed in asymptomatic patients who are found to have an unexplained leukocytosis when their complete blood counts are checked. Subsequent evaluation, including bone marrow aspiration and biopsy with cytogenetic analysis, reveal the Philadelphia chromosome.

Treatment

Imatinib mesylate (a drug that blocks an abnormal kinase made by Philadelphia chromosome positive CML cells) effectively reduces the number of tumor cells in the chronic phase of CML to normal in nearly 90% of patients. An alternative is stem cell transplantation.

leukemia cutis

An invasion of the dermis and subcutaneous fat by leukemic cells. The invasion often happens before these cells proliferate in the bone marrow or are detectable in the peripheral blood. The cells may cause several different types of skin rashes, including blue nodules (giving the skin a “blueberry muffin” appearance), papules, plaques, and ulcers.
Synonym: aleukemic l
Enlarge picture
HAIRY CELL LEUKEMIA: Bone marrow aspirate
Enlarge picture
LYMPHOCYTES IN HAIRY CELL LEUKEMIA

hairy cell leukemia

Abbreviation: HCL
A chronic, low-grade hematological malignancy of abnormally shaped B lymphocytes (“hairy cells”). The disease is marked by pancytopenia and splenomegaly. Median survival in untreated patients is about 5 years. The disease is rare, being only 1% to 2% of all leukemias. The median age of patients is 50 years; men are affected more commonly than women by a 4-to-1 ratio. See: illustration

Symptoms

Weight loss, hypermetabolism, infectious complications, and abdominal discomfort due to splenic enlargement are common.

Treatment

Cladribine, pentostatin, interferon alfa, and rituximab (a monoclonal antibody) are representative chemotherapeutic options.

illustration

mixed-lineage leukemia

Abbreviation: MLL
An aggressive, primarily childhood leukemia caused by the translocation of a gene from chromosome 11 to a region that overproduces fusion proteins.

Enlarge picture
HAIRY CELL LEUKEMIA: Bone marrow aspirate
Enlarge picture
LYMPHOCYTES IN HAIRY CELL LEUKEMIA

hairy cell leukemia

Abbreviation: HCL
A chronic, low-grade hematological malignancy of abnormally shaped B lymphocytes (“hairy cells”). The disease is marked by pancytopenia and splenomegaly. Median survival in untreated patients is about 5 years. The disease is rare, being only 1% to 2% of all leukemias. The median age of patients is 50 years; men are affected more commonly than women by a 4-to-1 ratio. See: illustration

Symptoms

Weight loss, hypermetabolism, infectious complications, and abdominal discomfort due to splenic enlargement are common.

Treatment

Cladribine, pentostatin, interferon alfa, and rituximab (a monoclonal antibody) are representative chemotherapeutic options.

illustration
See also: leukemia

HCl

Abbreviation for hydrochloric acid.

HCl

hydrochloric acid.
References in periodicals archive ?
HCL employs over 4500+ professionals, and provides transformational work for over 200+ European customers
HCL offers end-to-end cloud lifecycle management and orchestration platform to enterprises through HCL MyCloud to efficiently manage and control their hybrid cloud infrastructure.
Some of the prominent schools which have tied up with HCL Learning are DPS Ghana, Indian Language School Nigeria, DPS Academy Dubai, Indian School - Al Wadi Al Kabir and Euro School, Nepal.
Gopal said the buyout will help the company have a stronger focus and ''enablement from the global HCL resource pool technically and commercially.
HCL Technologies is a leading global IT services company, working with clients in the areas that impact and redefine the core of their businesses.
MP Sharma, president of Techmart Telecom said the company was excited about its strategic association with HCL which brings over a decade of expertise in the field of distribution.
HCL Infosystems, India's premier information enabling and integration company offers its customers technology solutions across multiple platforms.
In summary, we presented a case of HCL with an immunoprofile different from that of HCL-C, HCL-V, and HCL-J in that the cells were [CD10.
For enquiries please contact: Global Head, Corporate Communications Ajay Davessar HCL Technologies Ltd.
Avitas Harish Natarajan, chief executive officer, HCL Avitas, said that the company aims to treat 50,000 patients daily.
With the launch, HCL Infosystems MEA aims to further expand its geographical reach, establishing a foothold to fully implement its expansion plans in the region.
Vineet's dedication to the success of HCL Technologies has catapulted the company to a position of unparalleled market and thought leadership today," said Shiv Nadar, chairman and chief strategy officer, HCL Technologies.