Usefulness of Pseudocontinuous Arterial Spin-Labeling for the Assessment of Patients with Head and Neck Squamous Cell Carcinoma by Measuring Tumor Blood Flow in the Pretreatment and Early Treatment Period.

BACKGROUND AND PURPOSE: For the assessment of the treatment response in non-surgical treatment, tumor blood flow provides the functional information of the tumor which is different from the morphological information such as tumor volume. The purpose of this study was to evaluate the diagnostic value of tumor blood flow values obtained by pseudocontinuous arterial spin-labeling in patients with head and neck squamous cell carcinoma. MATERIALS AND METHODS: Forty-one patients with head and neck squamous cell carcinoma were evaluated by using pseudocontinuous arterial spin-labeling. Quantitative tumor blood flow was calculated at the pretreatment and the early treatment periods in all the patients, and the percentage change of tumor blood flow between the two was calculated. At the early treatment period, based on their tumor volume reduction rate, we divided the patients into stable disease and partial response groups for a subgroup analysis. The local control or failure was confirmed either by histopathology or by radiologic evaluation within the follow-up. RESULTS: Pretreatment tumor blood flow in patients in the failure group was significantly lower than that in patients in the local control group. In the subgroup analysis of patients with stable disease, the percentage change of tumor blood flow was significantly larger (due to the tumor blood flow increase from pretreatment value) in the local control group than in the failure group. In addition, in patients with a partial response, the percentage change of tumor blood flow was significantly smaller (due to the tumor blood flow decrease from the pretreatment value) in the local control group than in the failure group. The accuracy for determination of the local control group or the failure group in pretreatment tumor blood flow was 0.83 and that in the combination use of the percentage change of tumor blood flow and tumor volume in the early treatment period was 0.93. CONCLUSIONS: Tumor blood flow obtained by pseudocontinuous arterial spin-labeling can be useful for the determination of local control. The combined use of the percentage change of tumor blood flow and tumor volume had particularly high diagnostic accuracy.

Global DTP manufacturing capacity and capability. Status report: January 1995.

A recently completed survey of 63 manufacturers of diphtheria-tetanus-pertussis (DTP) vaccine and its components in 42 countries shows that there is potentially a large excess installed capacity for DTP production. However, many manufacturers are not producing to capacity, and demand and supply for this vaccine are not matched in individual countries. About half of all countries producing DTP vaccine and its components do not have fully functional national control systems, and some countries are performing none of the critical functions for an effective control of quality. Thus, potential for export of excess capacity is limited. The data collected indicate much homogeneity in the preparation of diphtheria and tetanus toxoids. Nearly all manufacturers use the same seeds and similar purification methods, but there is variability in whether purification is done before or after conversion of toxin to toxoid. About 10% of all manufacturers do not meet WHO-defined standards of purity for these toxoids. There is much more heterogeneity in the pertussis seed strains and the methods of purification used. The formulation of DTP vaccine differs considerably among producers. Potency testing is not being done by the WHO-recommended method by about 50% of manufacturers on lots of diphtheria and tetanus toxoids for release. Testing of irreversibility of conversion of toxin to toxoid, a WHO-specified safety test, is also not being done on each lot of diphtheria toxoid by 15% of manufacturers surveyed nor on each lot of tetanus toxoid vaccine by 30% of manufacturers surveyed. Access to technology to develop new DTP-based combination vaccines will be delayed if these manufacturers cannot ensure consistent high quality vaccine for their target populations. The results and conclusions suggest areas for future activities to strengthen the supply and quality of DTP and DTP-based combination vaccines.

The transfer of vaccine technology to developing countries. The Latin American experience.

Technological advances by developed countries are producing safer, more potent vaccines. In addition, the transfer of the technology of vaccine production to some developing countries has been taking place during the past five decades, thereby making possible the participation of developing countries in the production and supply of the essential biologicals that are required for immunization programs. Examples of successful transfers of technology, the decisive elements and factors that contribute to the transfers, and the major obstacles to such transfers are presented.

[Assessment and treatment of patients with dementia of the Alzheimer type].

Recently more than a dozen clinical trials for dementia of the Alzheimer type (DAT) have been conducted in Japan using almost the same diagnostic criteria and assessment procedures. Cholinomimetic drugs such as AChE or M1 agonist are the most common in the current clinical drug trials. DSM-IIIR and NINCDS-ADRDA are usually employed as diagnostic criteria. In the recent report on the sensitivity and specificity of these diagnostic criteria, it has been indicated that the clinician or researcher who wishes to ensure that patients classified as DAT are more likely DAT should choose DSM-III, whereas the investigator who wishes to include the greatest number or DAT cases, seldom assigning a diagnosis of no DAT to a true case, should choose NINCDS-ADRAD. Also, development of exclusion criteria for DAT would be essential to improve interrater reliability of these diagnostic criteria. In the recent clinical trials outside Japan, a dual assessment procedure consisting of objective psychometric test(s) to assess cognitive impairment and global clinical impression of change is a standard method to evaluate the clinical efficacy of drugs for DAT. In psychometric tests, Alzheimer's Disease Assessment Scale (ADAS) is the most common in the US and Hasegawa's Dementia Scale (HDS) in Japan. A Japanese version of ADAS-cog. has been already developed for use in clinical trials in Japan. Also, HDS has recently been revised to improve the sensitivity of the test. In addition, Clinical Dementia Rating (CDR) that is one of the common measures staging severity of dementia in Japan might be a better alternative to the conventional Clinical Global Impression of Change (CGIC) in the US.(ABSTRACT TRUNCATED AT 250 WORDS)