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Biomedical subjects

S Ratnam

Publications and source records attributed to S Ratnam.

121 records · Page 7Linked to original sources
PubMed1977

Mast cell response during the early phase of tuberculosis: an electron-microscopic study.

Guinea pig lungs were infected with Mycobacterium tuberculosis by intratracheal route and examined under electron microscope to investigate the morphological alterations of the organisms, if any, and the response of the host tissue. The bacilli showed no changes in their morphology, while the host tissues revealed several cells containing many electron-dense intracytoplasmic granules. These cells were predominantly seen during the 1st week of infection. The electron-dense bodies of these cells may be the ones observed by earlier workers and suggested to be the altered forms of tubercle bacilli. The present investigation, however, revealed them to be the granules of the mast cells. These cells were observed to respond to tuberculous infection during the first few days by appearing in large numbers crowded with intracytoplasmic granules and soon disintegrating as the result of subsequent degranulation. The above observation is presented and its significance discussed.

Animals↗
PubMed1977

The safety of local anesthesia and outpatient treatment: a controlled study of induced abortion by vacuum aspiration.

The safety of early vacuum aspiration performed as an outpatient procedure using local anesthesia was examined in a controlled study sponsored by the World Health Organization and undertaken in two centers in Yugoslavia and Singapore. The sample consisted of healthy women whose pregnancies were between 7 and 12 weeks in duration. Follow-up four weeks after abortion was nearly 100 percent in both centers. No important differences in complication rates were found between the different types of services and anesthesia, even though overall complication rates differed markedly between centers. Overnight postabortion observation was not associated with any decrease in complications.

Abortion, Induced↗
PubMed1977

Complications following induced abortion by vacuum aspiration: patient characteristics and procedures.

Complications following early induced abortion by vacuum aspiration were examined in a controlled study. Data were collected on healthy women 7--12 weeks pregnant at the time of abortion. No association was found between complication rates and age, marital status, or parity. However, women in their first pregnancies and those who had experienced an induced or spontaneous abortion in their previous pregnancy had a higher rate of complications following the current induced abortion.

Abortion, Induced↗
PubMed1976

The effect of gravitational forces on the viability of spheroplasts of mycobacteria.

Spheroplasts of Mycobacterium smegmatis and Mycobacterium tuberculosis were subjected to a wide range of centrifugal forces ranging from 583 g to 15 000 g after which their viability was determined by plating them on two types of media; one containing stabilizing agents and the other without them. Though there were minor fluctuations in the viable counts, there was no consistent decrease in their viability even in the absence of osmotic stabilizers.

Cycloserine↗
PubMed1976

The pathogenicity of spheroplasts of Mycobacterium tuberculosis.

Guinea pigs were injected with spheroplasts of Mycobacterium tuberculosis and were sacrificed after various intervals to study the state of the organisms and to evaluate the extent of disease. The spheroplasts persisted in the body of the animals for a considerable length of time. Their presence, however, was not associated with either the development of tuberculin hypersensitivity or pathologic changes. It was found that the spheroplasts were pathogenic only when reverted in the animals to bacterial forms. The reversion of the spheroplasts to bacillary state and the subsequent initiation of infection were dependent on the duration of their stay within the host.

Animals↗
PubMedDate not supplied

Human sperm function after coculture with human fallopian tubal epithelial cell monolayers: in vitro model for studying cell interactions in early human conception.

It has been difficult to study the behavior of sperm in the tubal environment in vivo. Human tubal epithelial cells were therefore cultured in vitro to simulate tubal conditions and human sperm function was assessed in the presence of such cells in vitro. Ampullary epithelial cell lines were established from fallopian tubes collected from premenopausal women undergoing hysterectomy. Approximately 1 x 10(5) cells/mL from monolayers of the third passage were seeded with 1 mL of culture medium into each well of 4-well plastic dishes. Sperm from 10 ejaculates of 10 different oligoasthenozoospermic men 30-41 years of age were recovered by the swim-up method and 200,000 sperm from each ejaculate were added into each well at the time of cell seeding. Control wells were treated the same but without cells. All dishes were incubated at 37 degrees C in 5% CO2, and sperm motility, acrosome reaction, and sperm-cell binding assessed at 1, 5, and 24 h. Curvilinear velocity and mean amplitude of lateral head displacement were significantly different in ampullary cultures as compared with controls for all three time periods: 1 h (67 +/- 5.2 vs 58 +/- 4.9 microns/s, p < 0.05; 4.48 +/- 0.4 vs 3.29 +/- 0.3 microns; p < 0.05), 5 h (75 +/- 5.8 vs 64 +/- 5.0 microns/s, p < 0.05; 4.92 +/- 0.5 vs 3.68 +/- 0.3 microns, p < 0.05), and 24 h (70 +/- 4.8 vs 59 +/- 4.2 microns/s, p < 0.05; 4.36 +/- 0.4 vs 3.11 +/- 0.3 microns, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Goat-associated Q fever: a new disease in Newfoundland.

In the spring of 1999 in rural Newfoundland, abortions in goats were associated with illness in goat workers. An epidemiologic investigation and a serologic survey were conducted in April 1999 to determine the number of infections, nature of illness, and risk factors for infection. Thirty-seven percent of the outbreak cohort had antibody titers to phase II Coxiella burnetii antigen >1:64, suggesting recent infection. The predominant clinical manifestation of Q fever was an acute febrile illness. Independent risk factors for infection included contact with goat placenta, smoking tobacco, and eating cheese made from pasteurized goat milk. This outbreak raises questions about management of such outbreaks, interprovincial sale and movement of domestic ungulates, and the need for discussion between public health practitioners and the dairy industry on control of this highly infectious organism.

Adult↗
PubMedDate not supplied

Measles immunization strategy: measles antibody response following MMR II vaccination of children at one year of age.

Measles antibody levels were determined by the plaque reduction neutralization (PRN) test in 580 one-year-old children before vaccination and four to six weeks after MMR II vaccination. Fifty-one (8.8%) had maternally derived measles antibody at prevaccination, and this was more common among children of women born before 1967 (10.6%) vs. 4.3%; p < 0.01). Among those with maternal antibody, only 22 (43.1%) responded with a protective PRN titre of over 120, in contrast to 463 (87.5%) of the 529 without maternal antibody at prevaccination (p < 0.0001). Also, the geometric mean titre was significantly lower for the former (114.1 vs. 378.5; p < 0.0001). Overall, 15 (2.6%) of the 580 children had no antibody response after vaccination, and a further 80 (13.8%) had a subprotective response (PRN titre < 120). This lack of response could not be attributed entirely to the presence of maternal measles antibody at the time of vaccination. The MMR II vaccine may not be sufficiently immunogenic in inducing adequate measles antibody response after a single dose given at one year of age.

Age Factors↗
PubMedDate not supplied

Immunity against measles in school-aged children: implications for measles revaccination strategies.

Measles serum antibody levels were determined by plaque reduction neutralization (PRN) test in 1,075 children in the age bracket of 5 to 17 years who received a single dose of measles-mumps-rubella (MMR II) vaccine at one year of age. Of these, 297 children (28%) had measles PRN titres < 120 which may not be protective against measles infection. The proportion of susceptible children by age ranged from 14 to 35%; however, there was no consistent age-dependent trend in susceptibility rates. The study data indicate the decline in protective immunity occurs before five years of age, and the proportion susceptible increases only slightly thereafter. This supports the current move towards a two-dose immunization strategy in the control and elimination of measles, with the second dose being given before school entry. The present data also underscore the need to consider a mass catch-up immunization program in the interim to prevent potential outbreaks of measles in school settings. The combination of the above approaches, if implemented as soon as possible, can potentially eliminate indigenous measles in Canada by the year 2000, the target date set by the Pan American Health Organization.

Adolescent↗