Biomedical subjects
Publications and source records attributed to M Y Lin.
Two hemagglutination (HA) antigens produced from Mycoplasma synoviae isolates WVU-1853m and FMT grown in Frey's mycoplasma broth were lyophilized for HA preservation. Some increase in the HA titer occurred following lyophilization.
The pH of Mycoplasma gallisepticum (MG) and M. synoviae (MS) growth medium was readjusted back to the original alkaline state when the pH reached 6.1 (for MG) and 6.7 (for MS), and the medium was reincubated until the pH of the medium returned to 6.7 to 6.9. The result was that MG and MS antigen yields were 43 and 54% higher than yields obtained at the usual harvest time.
The F strain of Mycoplasma gallisepticum (MG) was used either fresh or after lyophilization or freezing at -60 C to vaccinate young leghorn chickens. Vaccine stored either frozen or lyophilized for 22 months was also used. Each vaccine preparation was given at dosages ranging from 10(5) to 10(9) colony-forming units/ml. All dosage levels of MG significantly (P less than 0.05) reduced air-sac lesion scores after aerosol challenge with the R strain of MG at 6 weeks postvaccination, regardless of the method of vaccine preservation or storage.
The sensitivity and specificity of the microagglutination (MA), serum-plate-agglutination (SP), and hemagglutination-inhibition (HI) test for Mycoplasma gallisepticum (MG) were compared in groups of chickens infected with MG, M. synoviae, or Pasteurella multocida or inoculated with bacterins prepared from Staphylococcus aureus or Erysipelothrix rhusiopathiae. Of the three tests evaluated, the HI test had the highest specificity, but it was the least sensitive. Both the MA and SP tests were more sensitive than the HI test but lower in specificity. The MA test was less sensitive than the SP test in detecting antibodies against heterologous MG strains.
Progeny chicks of Mycoplasma gallisepticum (MG)-infected and MG-free white leghorns were used to evaluate the protective effects of maternal antibodies against aerosol challenge with the virulent R strain of MG at 3, 7, or 14 days of age. Interference by maternal antibodies with day-1 vaccination with the F strain of MG was also studied. In another trial, 8, 4, or 2 ml of high- or low-titered antiserum was given to 20-day-old commercial white leghorn chicks. Protection was measured in terms of air-sac lesions post-challenge with the R strain of MG as above. Maternal antibody in the chicks conferred very little protection against challenge and did not interfere with day-1 vaccination with the F strain of MG. Low-titered antibody gave no protection against growth of MG in the tracheas, but the high-titered MG antiserum did confer some protection against airsacculitis. This protection might be due to growth-inhibition antibody in the transferred serum.
Five trials were conducted to evaluate the virulence and the vaccination efficacy of the F, R, S6, and A5969 strains of Mycoplasma gallisepticum (MG) at different in vitro passage levels. Vaccination was done by eye-drop or aerosol, and efficacy was evaluated in terms of air-sac lesions after aerosol challenge with the R strain of MG. Continuing medium passage of these strains of MG resulted in gradual attenuation. Aerosol vaccination with highly attenuated MG at 21 days of age was more effective in stimulating the development of immunity than was eye-drop vaccination at 7 days, but aerosol vaccination induced more air-sac lesions. Aerosol vaccination with high-passaged F or S6 strain provided good immunity against MG challenge. Back-passage in chickens of the F strain of over 300 medium passages did not substantially increase the virulence, but back-passage of the S6 strain at the 258th passage and F strain at the 11th and 252nd passage did result in increased virulence. Both low- and high-passaged F and S6 strains were virulent for turkey poults, but only the high-passage F strain did not significantly (P less than 0.05) affect body weight.
Strain F of Mycoplasma gallisepticum was stored frozen at -60 C or -20 C in liquid medium with or without cryoprotective agents or was lyophilized with or without stabilizers and stored at 4 C. The titer was determined before, during, and after the subsequent storage period. In cultures frozen at -60 C or lyophilized, the titer had not significantly declined by the end of 371 days of storage. At -20 C, the titer of frozen cultures declined rapidly, and no mycoplasma had survived 282 days of storage. The addition of cryoprotective agents (10% glycerol or 8% dimethyl sulfoxide) or freeze-drying stabilizers (12% sucrose, or 7.5% glucose, 8% skim milk, or SPA) did not help maintain the viability of the mycoplasmas during freezing or freeze-drying process and the subsequent storage.
Strains F and R of Mycoplasma gallisepticum (MG) were compared for their pathogenicity in broad-breasted white turkey poults in terms of induction of airsacculitis, depression of growth rate, and induction of antibody production against MG. Eye-drop inoculation with the F or R strain produced only minimal lesions. However, aerosol exposure with either MG strain resulted in a significantly higher incidence and severity of air-sac lesions (P less than 0.001), reduction of growth rate (P less than 0.005), and hemagglutination-inhibition (HI) antibody titers against MG than did eye-drop inoculation. There were no significant differences between the two MG strains in effects on incidence of air-sac lesions or on growth rate.
The egg transmissibility of strains F and R of Mycoplasma gallisepticum (MG) was studied in 53 pullets by isolating MG from the eggs and embryos. MG was isolated at rates of 3.19% and 1.59% from the eggs of hens exposed by aerosol to the R or F strain, respectively. However, MG was isolated at rates of 0.19% and 0.00% from the eggs of chickens exposed by eye drop to the R or F strain, respectively. A statistically significant reduction in egg production was observed during the first 4 weeks postexposure in the group exposed to the R strain of MG by aerosol. An unexpected finding was significantly lower fertility of eggs from all MG-infected groups.
Five strains of Mycoplasma gallisepticum (MG) were tested for their cross-protection, virulence, and antigenic relationship in young leghorn chickens. Chickens vaccinated at 1 day of age by eye drop with the F or R strain of MG had good protection against aerosol challenge with the F, R, or S-6 strain at 4 weeks postvaccination. Chickens vaccinated at 1 day of age with the 503 or 730 strain had only partial protection against challenge with R, F, or S-6; the degree of cross-protection was related to the virulence of the vaccine strain used. In the hemagglutination-inhibition test, serum from chickens with single infection (vaccination and/or challenge with only one strain) with the F, S-6, or R strain reacted strongly with antigens prepared from S-6 and A5969 and reacted weakly with 730 and 503 antigens. Chickens with a single infection with the 503 or 730 strain reacted only with antigen prepared from the homologous strain. Serum from chickens with a two-strain mixed infection had a wider spectrum of HI activities. In the serum-plate-agglutination test, serum from chicken infected with the S-6, F, or R strain reacted with all antigens. Chickens infected with the 503 or 730 strain reacted more strongly with the homologous antigen. Antigen prepared from the S-6 strain of MG detected antibodies against the 503 and 730 strains more efficiently than did antigen prepared from the A5969 strain.
Two cases of intrathoracic migration of Kirschner wires are reported. Two wires were used to fix a left clavicle fracture in case 1. Two months later, a chest film showed a broken wire migrating into the mediastinum. A chest computed tomogram revealed the Kirschner wire penetrating into the main pulmonary artery. The broken wire was removed through sternothoracotomy after a pericardiotomy. In case 2, repeated blood-tinged sputum was experienced 5 years and 6 months after Kirschner wire fixation of 2 left clavicle fractures. Chest film showed the migrated wire located in the right thorax. The wire was removed through right thoracotomy. In both cases, the foreign bodies were successfully removed and vascular and pulmonary repair were performed without morbidity.
From 1982 to 1991, there were 57 patients diagnosed with various intracranial disorders manifested initially with acute hemiplegia at the Department of Pediatrics, National Taiwan University Hospital. There were 33 boys and 24 girls, aged 12 days to 18 years old. In etiological consideration, cerebrovascular disease (66.7%), intracranial tumors (12.3%) and head trauma (10.5%) accounted for most of the cases. Besides acute hemiplegia, cranial nerve palsy (47.4%), disturbed consciousness (42.1%), headache (42.1%), vomiting (31.6%), focal seizure (21.1%) and fever (21.1%) were also common manifestations. Neuroimage studies of CT/MRI scan and angiography were the most useful diagnostic tools. Treatment modalities included medical treatment in 25 patients and surgical intervention in 16 patients and supportive treatment in the others. There were 12 fatal cases, half of whom died directly of intracranial pathology. The survivors exhibited various neurological deficits, in which motor deficits, mental retardation, and subsequent seizures were the three most common sequelae.
Two boys (9 years and 14 years old) were brought to visit our pediatric endocrine clinic with the chief complaint of short stature. Because of growth retardation, they were admitted for further evaluation. Physical examinations, including neurological examinations, were unremarkable but the laboratory examination confirmed the diagnosis of hypopituitarism in both patients. Skull radiography examinations showed some calcifications at suprasellar regions in the case 1 but negative findings in case 2. Furthermore, computed tomography (CT) of the head of case 2 performed at an outside hospital half a year before was reported to be normal, so case 2 fits the conventional diagnosis of idiopathic hypopituitarism. However, magnetic resonance image (MRI) study of the head disclosed that both of them are victims of an intracranial tumor, craniopharyngioma and germ cell tumors respectively. After surgical intervention, followed by radiotherapy, both patients were stable without any neurological deficit. Our experience confirmed that an MRI study of sellar region is warranted in search of the etiology of hypopituitarism.
A case of rigid spine syndrome presenting with respiratory failure was reported. A seven-year-old girl had had dyspnea and orthopnea for one month. Symptoms had aggravated gradually and she was in a state of respiratory failure on arrival at our hospital. There was no evidence of active lung lesions and response to mechanical ventilation was good. Physical examination revealed an extremely thin girl with marked flexion limitation of neck and severe wasting of sternocleidomastoid and intercostal muscles. Serum creatine phosphokinase was moderately elevated (801 IU/L). Muscle biopsy specimen obtained from the right quadriceps femoris revealed increased perimyseal connective tissue and marked Type II fiber atrophy. Electromyography of left paraspinal muscles demonstrated small amplitude, short duration motor unit potentials. She received tracheostomy and a home-care ventilator use during sleep. Ventilatory insufficiency, though rare, should be anticipated in patients with rigid spine syndrome, and timely ventilatory support should be given.
Fifteen hemolytic gram-negative bacteria were isolated from the respiratory tracts of sick birds suffering from a long-lasting respiratory syndrome or from the bone marrow of dead birds distributed in the southern part of Taiwan. These were classified as Pseudomonas aeruginosa (10 isolates), Pseudomonas fluorescens (2 isolates), Pseudomonas stutzeri (1 isolate), Pasteurella haemolytica (1 isolate), and Proteus morganii (1 isolate). Each isolate was inoculated intraperitoneally into one group of ten 4-week-old male white leghorn chickens. Mortality and lesions were scored daily for 1 week. Three of the 10 isolates of Pseudomonas aeruginosa caused 100% mortality. Six other isolates of Pseudomonas aeruginosa and the one isolate of Proteus morganii caused 50% mortality. The remaining isolates induced less than 30% mortality. The sole nonpathogenic sample was one isolate of Pseudomonas fluorescens. When therapeutic levels of 22 antibiotics or sulfa drugs were evaluated for their inhibitory activity against the 15 isolates, the most effective were apramycin (15/15), gentamicin (15/15), spectinomycin (13/15), oxytetracycline (8/15), and sulfachloropyrazine (7/15). The least effective were ampicillin, cloxacillin, and tiamulin, which were not effective against any of the isolates. The 14 other drugs were of very low (> 4/15) effectiveness. Most of the isolates studied were virulent for chickens and very resistant to currently used drugs.