The effect of temperature on the efficacy of ozonation for inactivating Cryptosporidium parvum oocysts.

Examination of the effects of water temperature on the inactivation of Cryptosporidium parvum oocysts with ozone, ozonation experiments were conducted in a semi-batch mode with a wide temperature range of 3-30 degrees C. Inactivation was assessed in terms of mice infectivity and in vitro excystation. The temperature dependency of the CT products by a reduction in infectivity of 2 log10 could be described successfully by the Arrhenius equation, 1/CT = 1.086 x 10(18)e-12520/K where CT is the integrated ozone concentration over the contact time (mg/min/L) and K is the Kelvin temperature of water. As for the reduction in viability assessed by the excystation assay, protocol B, the obtained regression equation, 1/CT = 1.802 x 10(18)e-12640/K, was almost identical to that observed for the infectivity. Thus, the CT products required for a 2 log10 reduction in both infectivity and viability increased by an average factor of 4.2 for every 10 degrees C decrease in water temperature. Additionally, our findings suggested that the viability, as determined by protocol B, could substitute for animal infectivity in evaluating the effects of environmental factors on the efficacy of ozonation.

[Study of the two-step tuberculin tests and gamma-interferon assays in elderly persons].

Recently, an outbreak of lung tuberculosis among elderly residents happened in the home for aged, and it has become a social problem. To analyze the problem of tuberculosis in the elderly persons, we performed two-step tuberculin tests at two weeks interval and gamma-interferon assays for diagnosis of human tuberculosis to residents in the home for aged. 45 males (age; 77.3 +/- 8.9 SD) and 118 females (age; 81.9 +/- 8.6 SD) elderly persons (> or = 60) were examined. Standard dose of PPD was injected intracutaneously, and read at 48 hours. Erythema of 10 mm diameter or more was considered positive. The results were as follows. (1) The percentages of positive reactors in the 1st (T1) and the 2nd (T2) tuberculin tests were 50.3% and 68.1%, respectively. (2) The diameters of erythema and percentage of positive reactors (T1) did not very with age, but the size of erythema increased from 13.5 mm (T1) to 21.2 mm (T2) among those below 80 years, and from 13.0 mm (T1) to 16.4 mm (T2) among those 80 years or higher (p < 0.01). (3) The percentage of positive reactors (T1) varied by sex, namely males react stronger than females. (4) A dose of interferon-gamma released specifically in response to PPD stimulation of whole blood cultures showed no close relation with the diameters of erythema. In conclusion, tuberculin reactivity waned among elderly persons, and the fact suggests that they would have lower resistance against new infections, and as a result, they might have higher risk of developing tuberculosis. Elderly residents should be performed two-step tuberculin tests at the time of their entrance to the home for aged, and negative reactors should carefully be followed up.

[Tuberculosis infection control practice in hospitals from the viewpoint of occupational health].

Several outbreaks of tuberculosis (TB) among health care workers were reported recently in Japan. To assess the current situation of TB infection control practice in hospitals in Japan from the viewpoint of occupational health, we carried out a cross sectional survey by mail-questionnaires. The questionnaires with closed and open-ended questions to ask situation of TB infection control program in hospital were mailed to 542 hospital chiefs in and around Tokyo, Kantoh district. 269 replies were received. We analyzed them especially focussing on the prevention of TB among health care workers. Out of 269 hospitals replied, 39 of them had wards and/or beds designated for tuberculosis patients, 223 did not have, and 7 were unknown. 102 (38.9%) had set written tuberculosis infection control programs or guidelines, only 21 (53.8%) have set them even in hospitals with TB beds. 110 (42.0%) hospitals had triage system for identifying patients with active TB in the outpatient setting. Although, most health care workers underwent annual health check programs including chest X-rays, only 67 (25.6%) of the hospitals provide tuberculin skin test to their new recruits. 165 (63.0%) of hospitals admit that undiagnosed patients with respiratory symptoms may stay with immuno-compromised patients in the same room. Since administrative management, staff education, environmental control in work place, personal infection control and individual health care should be carried out from the viewpoint of occupational health, we showed concrete steps of these in this paper. We recommend that a TB infection control manager in each hospital should be designated, and that TB infection control program and/or guideline should be made. Environmental control in work place to prevent infection should be more prioritized in Japan.

[Koch's phenomenon after BCG vaccination and the two-step tuberculin test in elementary school children].

In Japan, BCG vaccination, which covers more than 90% of infants, has been given according to the national immunization policy. Moreover, first-grade children in elementary school are screened with tuberculin skin test, and those who show negative reaction in the Japanese standard, i.e. size of erythema less than 10 mm, are re-vaccinated with BCG according to the Tuberculosis Prevention Law. However, since the incidence of tuberculosis among children below age 14 is as low as 1.5/100,000 in Japan, it is time to reconsider the BCG vaccination policy. As the first step to assess the efficiency of the present program, we observed the occurrence of Koch's phenomenon after BCG vaccination in elementary school children in Chiba City in 1995 and 1996, and we introduced the two-step tuberculin test to elementary school children in 1997. Among 180 BCG vaccinated children in 1995 and 1996, 168 (93.3%) had been vaccinated by 4-year of age. We could follow local reaction of BCG re-vaccination and observed Koch's phenomenon in 117 (69.6%, 95% C.I. of 62.7-76.6%). Among 92 tuberculin negative children in 1997, 85 (92.4%) had been vaccinated by 4-year of age. In the two-step tuberculin test program of 85 initial negative-reactors, 63 (74.1%, 95% C.I. of 64.8-83.4%) turned to positive by the second test. Those results suggest that more than 69% of tuberculin-negative school children who were vaccinated previously maintained immunity with BCG. Our studies raised a problem of the current BCG re-vaccination policy that depends on the result of tuberculin test. Due to the discrepancy between tuberculin allergy and immunity in tuberculosis, many school children may be given BCG vaccination unnecessarily. Taking into consideration the incidence of tuberculosis in children, discontinuation of BCG re-vaccination policy at elementary school entrance should be considered.

Synthesis of oligonucleotide derivatives containing an azobenzene linker.

The linker containing azobenzene unit which can be used for joining two oligonucleotides via 5'-terminal hydroxyl group of one oligomer and 3'-terminal oxygen of another has been synthesized.

[Recent advances in imaging in diagnosis and treatment of tuberculosis].

Recent advances in imaging have been brought about by the the development of digital imaging modalities. The clinical application of these modalities for tuberculosis can be carried out in various situations, screening, differential diagnosis, examination for disease extend, marker of treatment response and checking the sequela. A digital image processing of contrast adjustment using Fuji Computed Radiography (FCR) produce more favorable chest image than that of spacial frequency enhancement. From our experience FCR proved superior to conventional film-screen system. CT has been considered to be very useful for detection and observation of tuberculosis lesion. Recently thin slice CT and high resolution CT have improved spacial resolution and these modalities are very useful to differentiate peripheral pulmonary nodule. Magnetic Resonance Imaging (MRI) completely differs from X-ray examination in terms of image parameter. The histologic resolution of this image is superior to any X-ray examination and Gd-DTPA enhancement will assist the differential diagnosis of nodular lesion. On the contrary, the spacial resolution of this chest imaging is inferior to CT because of respiratory motion. However, MRI application for brain is useful in diagnosis of cerebral tuberculosis. A spiral CT scanning has been developed for clinical use and three dimensional CT (3-D CT) can be obtained by this system.(ABSTRACT TRUNCATED AT 250 WORDS)

[Development of hepatocellular carcinoma in the patients with a history of tuberculosis].

Of the patients diagnosed as having hepatocellular carcinoma (HCC) at Chiba University Hospital and affiliated hospitals from 1978 to 1992. 191 patients with histories of having a blood transfusion more than 10 years ago were studied. Histories of having transfusions for tuberculosis were the most common, being documented by 50 patients. Of those patients receiving transfusions for tuberculosis, the average period from transfusion to the detection of HCC was 31.1 years and the average year of transfusion was 1955. Liver dysfunction was found during routine medical examinations of the most patients (38.9%), and HCC was diagnosed in 17% of the patients soon after the detection of liver dysfunction. Of the HCC patients with histories of tuberculosis treatment, anti-hepatitis C virus was frequently tested positive regardless of a history of transfusion. Patients with histories of transfusions for tuberculosis should continually be examined for liver dysfunction, and it must be considered that these patients have a risk of developing HCC.

[INH preventive therapy in Chiba Prefecture--before and after the renewal of the guideline].

To prescribe or withhold isoniazid (INH) for tuberculin skin test reactors is a difficult question in our country where BCG coverage rate is high. The guideline for INH preventive therapy renewed in 1989 says that the decision should be made according to the maximum erythema diameter of tuberculin skin test considering if the patient is a contact or non-contact, BCG vaccinated or non-vaccinated. In addition, evidence of recent infection is also important. We reported the INH preventive therapy in Chiba prefecture before and after the renewal of the guideline. There were 347 cases before and 571 after the renewal of the guideline. The cases of which maximum erythema diameter were coincided with the recommendation of the guideline were 50.2% and 78.6% respectively. Close contacts of infectious tuberculosis, i.e. cases founded out in extraordinary health examination and household contacts examination, showed high coincidence rate. On the contrary, tuberculin-positive infants found in routine health examination, who are neither contacts nor BCG vaccinated, showed low coincidence rate and seemed to be administered INH by their home- or school-doctors' own standards. These trends were the same before and after the renewal of the guideline.

[Ultrasonographic findings of abdominal tuberculous lymphadenitis].

Five patients with abdominal tuberculous lymphadenitis were studied by ultrasound. The final diagnosis of tuberculosis was based on open biopsy in 2 patients, neck lymph node biopsy in 1, needle biopsy under ultrasound control in 2. Low-echoic and iso-echoic abdominal lymph nodes were seen in all patients and a mixed echoic lymph node was found in one of them. Enlarged, round or oval, lymph nodes were conglomeratically observed along the common hepatic artery, in the hepatoduodenal ligament and along the abdominal aorta. The size of the lymph node was found to be 20-70 mm. In one case, compression of the portal trunk and the common bile duct due to a large lymph node was observed, and arterioportography showed hepatopetal collateral veins. In the other case, multiple mass lesions in the liver and the spleen were observed. In the 4 patients who were observed by ultrasound at 2 months after anti-tuberculosis therapy, enlarged lymph nodes decreased and 3 of them changed from low-echo to iso-echo in the echo pattern. Of the 4 patients who were followed for more than 4 months, lymph nodes disappeared in 2 at 4 months and in one at 12 months. The remaining patient showed residual nodes which decreased in half at 8 months. Ultrasound is now used commonly in the examination of the abdomen, and there are cases of abdominal lymph nodes swelling due to varied diseases. In this study, there were no characteristic ultrasonographic findings in abdominal tuberculous lymphadenitis. So, it is difficult to diagnose the cause of abdominal lymph node swelling by only ultrasound.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pulmonary Tuberculosis in foreigners].

We studied the background and social problems of pulmonary tuberculosis in foreigners which we recently encountered at the National Chiba- Higashi Hospital and the Chiba Anti-tuberculosis Association. 1) The number of foreigners with pulmonary tuberculosis has been increasing year by year, one in 1983, none in 1984 and 1985, one in 1986, two in 1987 and four in 1988. 2) Most of these patients had been already infected or had some symptoms before their arrival to Japan. 3) Their background includes some serious social problems such as troubles in daily life coming from linguistic and cultural differences and economic difficulties, legal problems such as illegality of their stay in Japan, etc. 4) Most of the above cases could not be treated sufficiently because they are foreigners or because of their illegal stay.

[Group infection of tuberculosis in a private extra-school tutoring institute].

1) Two students of different high-schools were found to have pulmonary tuberculosis by school medical examination. These two students learned in the same private extra-school tutoring institute when they were junior high-school students. Assuming this event as a group infection of tuberculosis in the extra-school tutoring institute, we performed an extraordinary examination on the teachers working there. 2) In the extraordinary examination, a patient who could be judged as the source of infection was found. 3) As a result of extraordinary examination on students learning in the institute, a bimodal distribution was noted in the size of tuberculin test, compared with the results of tuberculin test at the first grade of junior high-school, the reaction was amplified. Twenty four students were subjected to chemoprophylaxis. 4) One case of pleurisy occurred from a student recommended chemoprophylaxis by the ad hoc committee on epidemic of tuberculosis, and the recommendation was neglected by an attending physician.

[A quality control of interpretation of rolled radiophotogramme used for mass screening of lung cancer in general habitants--cases difficult-to-diagnose and cases difficult-to-detect].

A mass screening for lung cancer was performed on 1,906,660 general habitants of Chiba Prefecture, using rolled radiophotogrammes (RP), a traditional mass screening method used for tuberculosis. Of those examined, 270 lung cancer cases were found. In order to evaluate the quality of RP interpretation, cases difficult-to-diagnose and cases difficult-to-detect were picked out from the detected lung cancer cases. Difficult-to-diagnose cases were defined as cases in which pulmonary tumor was not suspected in the screening. Among these cases, tuberculosis was the disease most frequently suspected. Thus, we reexamined the RP which were suspected as being tuberculosis or pulmonary tumor. There was no difference between the two diseases in terms of the location of pathological shadows. Isolated small nodular shadows and infiltrating shadows were seen as an indication of tuberculosis, while large nodular shadows were thought to indicate pulmonary tumor. In addition, by retrospectively examining the RP of the cases judged as normal in the screening of the previous year, tumor shadows could be found in 54.2% of the cases. These cases were considered to be difficult-to-detect cases of lung cancer. The tumor shadows of many cases were present in the hilar region in these re-examined X-ray films. It was difficult to recognize these shadows in the rolled X-ray films because small nodular shadows or infiltrating shadows overlapped with the opacities of normal structures. To overcome these problems of difficult-to-diagnose cases and difficult-to-detect cases, the following observations are important. (1) Care should be taken in order to obtain photogrammes with excellent quality.(ABSTRACT TRUNCATED AT 250 WORDS)

[Extraordinary examinations in tuberculous prevalence areas and family contact examinations].

A survey was made on the actual state of performance of extraordinary examinations done in high tuberculosis prevalence areas and those of family contact examinations of the index cases of tuberculosis during the period between April 1986 and November 1987 in Chiba Prefecture. The results are as follows: (1) Forty-eight extraordinary examinations were performed by 19 public health centers. (2) By these extraordinary examinations, 22 additional tuberculous patients were detected and 143 persons were indicated INH prophylaxis. There were 2 cases of mass tuberculosis infection: from which 19 patients and 140 persons for chemoprophylaxis were detected. (3) Out of 18 extraordinary examinations done for contacts of cases from danger groups, one was done actually for unnecessary case. As to tuberculin tests, they were not performed in 2 groups, and in another case, the test subjects were inappropriate. (4) The examination rate of family members of index cases was as high as 95.4%, whereas the performance of tuberculin tests was not satisfactory, especially as regards to the younger populations. The total performance rate of the tests was 29.0%, and the rate in those below 19 years of age was 56.5%, and the rate in those below 29 was 42.9%. (5) There were 6 families with tuberculosis, which included 14 patients. It is considered that in extraordinary examinations, appropriate setting of subjects and tuberculin tests for younger persons are important; in family contacts examination, tuberculin tests for younger persons are indispensable.

[Deformity of the cardiac structures in patients with mitral valve prolapse: the relationship with flat chest].

In view of the close relationship of mitral valve prolapse (MVP) and chest deformity, seven patients of MVP associated with flat chest were echocardiographically evaluated, and the results were compared with those of 43 normal control subjects, 29 cases with flat chest, and patients with MVP either of the anterior (25 cases) or posterior (21 cases) leaflet. MVP associated with flat chest was observed in the anterior leaflet in all cases. MVP was related to the dislocation of the two mitral leaflets caused by the displaced posterior mitral ring observed by two-dimensional echocardiography. The transition type was observed among the cases with or without dislocation of the mitral ring in cases with flat chest.