Saturday January 25, 2020

Changing the Dose of TB Vaccination may Improve its Efficacy: Study

New approach improves efficacy of TB vaccine says a new study

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TB vaccination
Tuberculosis (TB) is the leading infectious cause of death globally, yet the world's only licensed TB vaccine, Bacille Calmette-Guerin (BCG), was developed a century ago. Pixabay

Researchers have shown that simply changing the dose and route of administration from intradermal (ID) to intravenous (IV) greatly increases the vaccine’s ability to protect rhesus macaques from infection following exposure to Mycobacterium tuberculosis (Mtb), the bacterium that causes TB.

Tuberculosis (TB) is the leading infectious cause of death globally, yet the world’s only licensed TB vaccine, Bacille Calmette-Guerin (BCG), was developed a century ago.

Given to infants via a needle placed just under the skin, BCG protects babies from a form of the disease called disseminated TB but is far less effective at preventing pulmonary TB.

The findings from University of Pittsburgh in US, provide a new understanding of the mechanisms of BCG-elicited protection against tuberculosis infection and disease.

In addition, the finding, published in the journal Nature, supports investigation of IV BCG administration in clinical trials to determine whether this route improves its effectiveness in teens and adults.

According to the researchers, to control Mtb infection and prevent clinical disease, a TB vaccine must elicit strong, sustained responses from the immune system’s T cells, specifically those in the lungs. However, the standard, ID, route of BCG administration may not generate enough of these critical cells in the lungs.

TB
A TB vaccine must elicit strong, sustained responses from the immune system’s T cells, specifically those in the lungs. Pixabay

The research team hypothesized that administration of BCG by IV or aerosol (AE) routes would overcome this hurdle and thus confer substantially better protection from infection and disease in rhesus macaques following challenge with virulent Mtb. In their study, groups of animals received the BGC vaccine by ID, AE or IV routes.

The scientists assessed immune responses in blood and in fluid drawn from the lungs for a 24-week period following vaccination. IV BCG vaccination resulted in the highest durable levels of T cells in the blood and lungs.

Six months after vaccination, the researchers exposed groups of vaccinated rhesus macaques (immunized via ID, AE or IV routes) and a group of unvaccinated macaques to a virulent strain of Mtb by introducing the bacteria directly into the animals’ lungs. They then tracked the infection and disease development over three months.

Nine out of 10 animals vaccinated with IV BCG were highly protected; six showed no detectable infection in any tissue tested and three had only very low counts of Mtb bacteria in lung tissue.

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All unvaccinated animals and those immunized via ID or AE routes showed signs of significantly greater infection.

The investigators concluded that IV BCG conferred an unprecedented degree of protection in an animal model of severe TB and ‘represents a major step forward in the field of TB vaccine research.’ (IANS)

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Here’s Everything you Need to Know About Male Breast Cancer

Know about the rarely seen breast cancer in men

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Breast Cancer
Male breast cancer is rarely seen and that is people are not aware about it. Pixabay

Breast cancer in men is rarely seen. It shares many similarities with cancer of the breast in women but there are some important differences too.

Male breast cancer represents between 0.5 and 1 per cent of all breast cancers diagnosed each year. Higher rates of male cancer in central and eastern Africa may be related to higher liver infectious diseases that lead to hypoestrogenism.

Dr Kumardeep Dutta Choudhury, Senior Consultant & Head of Department, Dept of Medical Oncology (IOSPL), Fortis Hospital, Noida, shares the facts you need to know about it.

Risk factors associated with breast cancer in men:

Genetics and family history

Breast Cancer
Higher rates of male breast cancer in central and eastern Africa may be related to higher liver infectious diseases that lead to hypoestrogenism. IANS

Family history of cancer in a first-degree relative is associated with an increased risk of breast cancer among men. Approximately 15 to 20 per cent of men with breast cancer have a family history of the disease compared with only 7 per cent of the general male population.

The risk is higher with inherited BRCA2 rather than BRCA1 mutations. Other genes which have been associated with an increased risk of breast cancer in men are PTEN tumor suppressor gene (Cowden syndrome), tumor protein p53 (TP53; Li-Fraumeni syndrome), partner and localizer of BRCA2 (PALB2), and mismatch repair genes (Lynch syndrome).

Alterations of the estrogen to androgen ratio

Excessive estrogen stimulation may be due to hormonal therapies (e.g., estrogen-containing compounds or testosterone), hepatic dysfunction, obesity, marijuana use, thyroid disease, or an inherited condition, such as Klinefelter syndrome may increase risk of male breast cancer.

Primary testicular conditions

Testicular conditions may increase risk of breast cancer in men include orchitis, undescended testes (cryptorchidism), and testicular injury.

PRESENTATION:

Male breast cancer has been diagnosed at a more advanced stage than female breast cancer, due to a lack of awareness. They generally present with a painless, firm mass that is usually subareolar, with nipple involvement in 40 to 50 percent of cases. The left breast is involved slightly more often than the right, and less than 1 percent of cases are bilateral. There may be associated skin changes, including nipple retraction, ulceration, or fixation of the mass to the skin or underlying tissues. Axillary nodes are typically palpable in advanced cases.

Breast Cancer
Excessive estrogen stimulation may be due to hormonal therapies can lead to breast cancer. Pixabay

Most histologic subtypes of that cancer seen in women are also present in men, men with breast cancer are rarely diagnosed with lobular carcinomas is due to lack of acini and lobules in the normal male breast, although these can be induced in the context of estrogenic stimulation.

TREATMENT:

Approach to treatment in men is same as that for women. However, role of breast conserving surgery is limited because of small volume of breast tissue. In hormone receptor-positive disease, we give adjuvant tamoxifen rather than an aromatase inhibitor (AI), because of insufficient evidence to support AI monotherapy for men. If there are contraindications to tamoxifen (e.g., hypercoagulable state), an AI with GnRHa may be administered. AIs do not reduce testicular production of estrogens, that’s why GnRHa is administered concurrently with AI. They are treated with mastectomy, radiotherapy, chemotherapy and hormone therapy.

SURVEILLANCE:

Limited data suggest these patients are at an increased risk of a contralateral breast cancer, but absolute risk is low. They are also at risk for secondary malignancies and 12.5 percent may develop a second primary cancer. The most common types were gastrointestinal, pancreas, non-melanoma skin, and prostate cancer.

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PROGNOSIS:

Ten-year disease-specific survival rates for histologically negative nodes – 77 and 84 per cent, one to three positive nodes – 50 and 44 per cent and four or more histologically positive nodes – 24 and 14 per cent. (IANS)