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Biomedical subjects

T Poon-King

Publications and source records attributed to T Poon-King.

At least 37 records · Page 2Linked to original sources

Lymphocyte cell subpopulations during acute post-streptococcal glomerulonephritis: cell surface antigens and binding of streptococcal membrane antigens and C-reactive protein.

T lymphocyte surface markers were examined in 23 patients with acute post-streptococcal glomerulonephritis (AGN) in parallel with normal controls and individuals without nephritis who showed evidence of pharyngeal or skin-sore beta-haemolytic streptococcal infection. Numbers of T gamma cells were similar in AGN and normal controls but were significantly lower (P less than 0.05) than those in skin-sore culture-positive streptococcal infection controls. Numbers of T mu cells were similar in AGN and normal controls but were lower (P less than 0.05) than those observed in streptococcal controls. Percentages of T mu cells were similar in AGN and normal controls but were lower (P less than 0.05) than those recorded in streptococcal infection control groups. Proportions of T cells were reduced during AGN (P less than 0.05). Lymphocytes capable of binding type 12 group A streptococcal membranes were increased (30.4%) in patients with AGN as compared to normal controls (4.1%). Subjects with streptococcal infection alone showed elevated but intermediate relative numbers (10.5%) of lymphocytes binding group A membranes. Increased relative numbers of both B and T lymphocytes binding group A streptococcal membranes were present in both AGN and non-nephritogenic streptococcal infection controls.

Acute Disease↗

Lymphocytes binding C-reactive protein and streptococcal membranes in acute rheumatic fever.

Peripheral blood lymphocytes binding CRP and streptococcal membrane antigens were studied in 19 patients with ARF with the use of a number of paired analyses for cell surface markers. A small fraction (6.9%) of T cells showed binding to streptococcal membrane. A large degree of overlap (38% to 46%) occurred in membrane-binding T cells and those with identifiable CRP. One third of T gamma cells showed CRP bindings, and approximately one quarter to T gamma cells in both ARF patients and normal controls showed membrane la antigen. A considerable concordance (50% to 75%) was noted between T cells binding streptococcal membrane and cells positive for la antigen. In contrast to T cells, B cells bearing CRP showed less overlap (mean 11%) with cells binding streptococcal membrane. Since B cells with concomitant surface immunoglobulin and la antigen constituted the major lymphocyte subpopulation binding streptococcal membrane antigens, relative exclusion of streptococcal membrane binding by B cells with surface CRP may represent natural protective modulation whereby proportions of potential antigen-binding B cells are defused by lymphocyte membrane CRP.

Acute Disease↗

Clinical healing two to six years after poststreptococcal glomerulonephritis in Trinidad.

To determine the incidence of chronic nephritis after poststreptococcal acute glomerulonephritis in Trinidad, 760 patients (41 adult) were examined two to six years after recovery from the illness, 344 being studied twice (four and six years). Only 1.8 per cent had persistent urine abnormalities on their last follow-up examination, and another 8.0 per cent had abnormalities that were transient or occurred only after the patient had assumed the lordotic position. In 1.4 per cent hypertension was present, whereas only one had azotemia. Both persistent urine abnormalities and hypertension increased in prevalence with age at onset of prior poststreptococcal glomerulonephritis but did not vary between sexes, races or epidemic versus endemic forms. Half the urine abnormalities present four years after recovery were absent two years later. Thus, poststreptococcal acute glomerulonephritis appears to have a low incidence of chronicity in Trinidad, with continuing resolution for more than four years.

Acute Disease↗

Tropical acute rheumatic fever and associated streptococcal infections compared with concurrent acute glomerulonephritis.

Ninety-three patients with acute rheumatic fever and 195 patients with acute glomerulonephritis were observed in Trinidad during an outbreak of scabies with a high incidence of secondary streptococcal infections. Clinical and laboratory manifestations of ARF were the same as those seen in temperate zones, except that antistreptolysin O titers were less markedly increased. The patients with ARF were similar to those with AGN in respect to sex, race, location of residence, and living conditions, but were older and had markedly fewer skin infections. Currently prevalent nephritogenic streptococcal strains never were isolated from patients with ARF even when M55 streptococci appeared and led to an epidemic of AGN.

Acute Disease↗

The families of patients with acute rheumatic fever or glomerulonephritis in Trinidad.

The families of 21 patients with acute rheumatic fever (ARF) and 44 patients with acute glomerulonephritis (AGN) in Trinidad were examined in their homes. The ARF and AGN families were equally large and crowded and they lived in the same largely rural areas. However, only 22% of the ARF family members had skin infections in contrast to 61% of the AGN family members. Sixty-eight per cent of skin infections in ARF families and 69% of skin infections in Agn families yielded group A streptococci. Throat cultures were positive in 19% of ARF family members and 25% of AGN family members. Thirty-two per cent of 51 group A strains isolated from ARF family members (29 from throat, 22 from skin) were M11 or "M41" strains which were associated with ARF during the study, while only 8% were M1, T4 (MNT or 60) or M55 strains which were associated with AGN. In contrast, 49% of 171 group A strains isolated from Agn family members (64 from throat, 107 from skin) were M1, T4 (MNT or 60) or M55 while only 10% were M11 or "M41." Serum antibody titers were similar in both groups: antistreptolysin-0 titers were not markedly increased in either while anti-hyaluronidase and/or antideoxyribonuclease-B titers were increased in both. Evidence of subclinical AGN was found equally often in both groups: 6% of each had abnormal urine and 4% of each had decreased serum complement while 2% of the ARF and 3% of the AGN family members had both abnormal urine and decreased serum complement.

Adolescent↗

Immunoglobulins and complement components in synovial fluid of patients with acute rheumatic fever.

Three components of complement and six other serum proteins were assayed in synovial fluid and serum samples from 25 patients with acute rheumatic fever in Trinidad. The resulting data indicate a relative decrease in both early and late components of complement within the synovial fluids which suggests local activation by immune complexes. Such activation of complement within the joint spaces may play a primary role in development of the inflammatory arthritis of acute rheumatic fever.

Adolescent↗

Salivary immunoglobulins and streptococcal antibodies in patients with acute rheumatic fever.

Evidence of a local immunologic response to recent pharyngeal infection with group A streptococci was sought in 23 patients with acute rheumatic fever. Salivas from these patients were examined and compared with salivas from control subjects. As assayed, both IgG and IgA values ranged between 8 and 170 mg. per 100 ml. in 10-fold concentrated samples of saliva. When these values were corrected for the concentration of the samples and for the use of serum IgA standards, the following mean values were obtained: for patients with acute rheumatic fever, IgG was 4.5 mg. per 100 ml. and IgA was 8.7 mg. per 100 ml.; for control subjects, IgG was 5.0 mg per 100 ml. and IgA was 9.9 mg. per 100 ml. IgM was present in amounts of 1 to 2 mg. per 100 ml. in 2 patients and 7 control subjects. Antistreptolysin O titers correlated with amounts of IgG in the saliva samples while antihyaluronidase, antigroup A carbohydrate, and antiteichoic acid titers did not. None of the antibody titers correlated with the IgA content of the saliva samples. Furthermore, saliva antibody titers did not differ between patients with acute rheumatic fever and control subjects.

Acute Disease↗