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PubMedDate not supplied

[Does the lack of availability of information represent a bottleneck for research and evaluation in health policy?].

OBJECTIVES: This article describes the difficulties encountered in obtaining information about health services, sanitation and health insurance coverage supply, use and coverage regarding a sample of Colombian municipalities during 1991-2000. The availability of information is also analysed in terms of decentralisation and municipal development. METHOD: This was a cross-sectional study of a random stratified sample of 495 Colombian municipalities; information regarding the variables of interest was requested at municipal and departmental level and from national sources. A scale was constructed for measuring the availability of information at local level. Non-parametric statistics were used for testing differences in availability of information in terms of certification and municipal category. RESULTS: Applying the scale revealed 51% availability of data regarding health service supply, 39% for data regarding service use and 45% for both types of information (supply and demand taken together). No information was available in 32% of the municipalities. Information was more readily available in non-certified and less developed municipalities. CONCLUSIONS: Study findings provided indirect evidence of difficulty in obtaining information regarding health systems at both municipal and departmental levels; this represents an important obstacle for health system management and evaluating performance, as well as for research and widening knowledge (and availability to such knowledge) in this area.

Colombia↗

PubMed2004

[Availability of essential drugs in two regions of Minas Gerais, Brazil].

OBJECTIVE: To investigate the availability of essential drugs in municipalities with a human development index < 0.699. METHODS: We surveyed 69 institutions, including municipal pharmacies, public clinics, private and philanthropic health units, and commercial pharmacies, in 19 municipalities of the state of Minas Gerais, Brazil. The municipalities were chosen according to the following selection criteria: (1) a human development index (HDI) < 0.699 (the HDI for the entire state of Minas Gerais in 1991) in the microregion where the municipality was located; (2) the municipality had to be the seat of government for the microregion where it was located; (3) there had to be at least two eligible institutions (belonging to the public, private, or philanthropic sectors) in full functioning in the municipality during the survey period. Health professionals who were directly responsible for stock control and drug dispensation at the institutions surveyed were interviewed. Institutional documents and records were also reviewed. A list of 21 tracer essential drugs, which were selected among the drugs most widely employed in the State of Minas Gerais' Basic Pharmacy Program, was used to measure availability. The availability of each tracer drug was calculated at the time of the site visit and for the 12-month period immediately before the survey. In addition, the availability of tracer drugs was calculated for each type of institution surveyed. RESULTS: The availability of essential drugs in municipal pharmacies was 52.0%; in public health clinics, 46.9%; and in philanthropic and private health units, 41.0% and 38.1%, respectively. In commercial pharmacies, the availability of essential drugs reached 81.2%. CONCLUSION: The availability of essential drugs in public facilities is low and varies widely, with the result that persons who need such drugs the most are often those who lack access to them. Private pharmacies are the main source of essential drugs. The results of this study point to the need to seek increased awareness and implementation of the concept of essential drugs throughout the country.

Brazil↗

PubMed2006

Evaluation of product switching after a state Medicaid program began covering loratadine OTC 1 year after market availability.

OBJECTIVE: The conversion of loratadine from prescription (Rx)-only to over-the-counter (OTC) status on November 27, 2002, brought about the question of how OTC products may influence utilization of both OTC and Rx-only low-sedating antihistamines (LSAs) simultaneously. North Carolina (NC) Medicaid initially did not cover loratadine OTC but subsequently changed the policy 1 year after OTC conversion, on November 23, 2003. The objective of this study was to determine patterns of LSA utilization in relation to changes in OTC availability and Medicaid coverage policy and to assess the rate of product switching associated with these policies. METHODS: Administrative pharmacy claims from the NC Medicaid population of approximately 1.1 million eligible recipients were used to study the 3 years of LSA use between July 1, 2001, and June 30, 2004. Two general methods were employed to evaluate the extent of product switching. First, monthly rates of incident use, new starts (i.e., no LSA use in the prior 12-month period) and product switching in time series were determined. These series were constructed to include a baseline period of no OTC availability, a period of OTC availability without coverage, and a period of OTC availability with coverage. Second, product switching was assessed through the use of rate-ratio calculations. Three equal 12-month periods were compared using rate ratios: (1) a baseline referent period (July 1, 2001, to June 30, 2002) during which loratadine OTC was not yet available, (2) a noncoverage period (July 1, 2002, to June 30, 2003) during which loratadine OTC was introduced to the market but not covered by NC Medicaid, and (3) a coverage period (July 1, 2003, to June 30, 2004). The primary comparison periods for the 3 years were the 5-month periods from February to June of each year. RESULTS: The use of individual drugs within the LSA class responded to coverage changes as expected, with alternative LSAs replacing loratadine use in the loratadine noncoverage period. Switching behavior for individual drugs within the LSA class was strongly associated with coverage changes. Recipients using loratadine were 2.16 times more likely to switch to an alternative Rx-only antihistamine in the noncoverage period (95% confidence interval [CI], 2.10-2.22) as compared with the baseline period. Yet they were only 1.11 times as likely not to use an Rx LSA during the last 5 months of the noncoverage period (95% CI, 1.09-1.13), as compared with the baseline period, suggesting minimal OTC uptake. The largest 12-month percentage increase in market share was observed for cetirizine (13.4%) although desloratadine accounted for the largest switch rate from loratadine at 3.10 (95% CI, 2.91-3.30), as compared with the baseline period, with a total market share increase of 7.8%. This suggests that new users of LSAs were most likely to initiate therapy with cetirizine, while existing loratadine users were most likely to switch to desloratadine. Compared with baseline switch rates, LSA users were only 0.34 (95% CI; 0.32-0.37) times as likely to switch to loratadine OTC from another (Rx-only) LSA during the subsequent OTC coverage period. LSA expenditure per member per month (PMPM) was essentially constant over time, at dollar 3.03 in the 5-month pre-OTC period, dollar 2.96 in the 5-month loratadine noncoverage period, and dollar 2.93 in the 5-month coverage period for loratadine OTC. Total LSA utilization increased slightly, from 1.37 days PMPM in the 5-month pre-OTC period to 1.41 in the 5-month loratadine noncoverage period and 1.45 in the 5-month coverage period for loratadine OTC. Loratadine OTC accounted for only 4.1% of the total LSA days of therapy and 4.2% of the LSA patients in the 5-month OTC coverage period from February to June 2004. CONCLUSION: Medicaid recipients switched to another covered (Rx) LSA when loratadine became available as an OTC and was not covered. After the subsequent policy change 1 year later to cover loratadine OTC, there was little switching to loratadine OTC. Though the average cost per LSA claim dropped dollar 4.15 (6.6%), from dollar 62.79 in the baseline period to dollar 58.64 in the OTC coverage period, time-series and rate-ratio results suggest that an additional dollar 6.01 (10.2%) could have been saved per LSA claim had OTC coverage been in effect at the time of the conversion of loratadine to OTC status. Although coverage of loratadine OTC offers a substantial cost-savings opportunity for the Medicaid program compared with Rx-only LSAs, not covering the OTC product immediately at the time of OTC availability contributed to (a) increased switching to Rx-only LSA products and (b) little use of loratadine OTC in the subsequent OTC coverage period.

Cetirizine↗

PubMed1981

Alcohol availability and cirrhosis mortality rates by gender and race.

This study test whether the availability of alcoholic beverages is a simple integrated dimension as implied by certain policy models and in its treatment by researchers. Factor analysis reveals two independent availability factors: on-premise and retail availability. A correlation analysis found that on-premise availability was related to cirrhosis mortality rates for the total population, White males, non-White males, and White females. It was not related to non-White female cirrhosis mortality. In contrast, retail availability was not related to any of cirrhosis mortality rates. Examination of the states with extremes of high and low on-premise availability indicates that this type of availability is not a manipulable control variable but an index of extant norms toward drinking. It is recommended that differential prevention strategies be adopted rather than a uniform policy prevention model.

Alcoholic Beverages↗

PubMed2002

Influence of availability of clinical history on detection of early stroke using unenhanced CT and diffusion-weighted MR imaging.

OBJECTIVE: The radiologic diagnosis of stroke requires accurate detection and appropriate interpretation of relevant imaging findings; both detection and interpretation may be influenced by knowledge of the patient's presentation. In our study, we evaluated the effect of the availability of clinical history on the sensitivity for stroke detection using unenhanced CT and diffusion-weighted MR imaging. MATERIALS AND METHODS: The records of 733 consecutive patients with a clinically based admission diagnosis of early stroke were reviewed. Among the criteria for inclusion in our study were the availability of an unenhanced CT scan (561 cases) or diffusion-weighted MR imaging examination (409 cases) obtained at admission and a discharge diagnosis indicating whether a patient had actually had a stroke. The radiology requisition forms, available at the time of image interpretation, were classified as either indicating or not indicating a clinical suspicion of early stroke. Sensitivity, specificity, and accuracy of stroke detection were computed, stratified by the presence or absence of an available history indicating suspicion of stroke. Results were compared using the Fisher's exact two-tailed test. RESULTS: Unenhanced CT sensitivity was 52% (specificity, 95%) for the suspicion-of-stroke group and 38% (specificity, 89%) for the no-suspicion-of-stroke group (p = 0.008). Diffusion-weighted MR imaging sensitivity was 95% (specificity, 94%) for the suspicion-of-stroke group and 94% (specificity, 98%) for the no-suspicion-of-stroke group (p = 0.822). CONCLUSION: Availability of a clinical history indicating that early stroke is suspected significantly improves the sensitivity for detecting strokes on unenhanced CT without reducing specificity. In contradistinction, the availability of such a history did not significantly improve the sensitivity for detecting stroke using diffusion-weighted MR imaging. Whenever possible, relevant clinical history should be made available to physicians interpreting emergency CT scans of the head.

Aged↗

PubMed1992

Context availability and the recall of abstract and concrete words.

Predictions of an automatic-imagery, strategic-imagery, and context-availability hypothesis of concreteness effects in free recall were examined. In each experiment, recall of abstract and concrete words controlled for rated context availability was compared with the typical situation in which context availability is confounded with imageability. In Experiment 1, a directed intentional-recall task produced concreteness effects in recall. Experiment 2 compared concreteness effects in recall following three orienting tasks: imagery rating, context-availability rating, and a directed intentional-memory task. Concreteness effects in the context-availability-controlled condition were found following the imagery-rating and the directed intentional-memory tasks, but not after the context-availability-rating task. In Experiment 3, subjects reported the strategies that they used to encode the list. Subjects reporting an imagery strategy showed concreteness effects for words controlled for rated context availability, but those not reporting it did not. These results support a strategic-imagery view of concreteness effects in free recall.

Humans↗

PubMedDate not supplied

Availability of school physical activity facilities to the public in four U.S. communities.

PURPOSE: This study documents the public availability of school physical activity facilities, reasons facilities were not made available to the public, and the barriers and benefits associated with having facilities available. DESIGN: Cross-sectional. SETTING: All schools located in four geographic locations (Washington County, Maryland; northwest suburbs of Minneapolis, Minnesota; Jackson, Mississippi; and Forsyth County, North Carolina). SUBJECTS: The survey was completed by 289 school representatives for a response rate of 82.3% (289/351 schools). For the nonrespondents, 61 of 62 schools were visited to obtain information on outdoor facilities. MEASURES: Information on indoor and outdoor physical activity facilities available to the public was collected for all schools (public, private, and colleges) using a telephone survey. Site visits were made to schools that did not participate in the survey to collect information on outdoor facilities only. RESULTS: The schools in the four geographic areas owned a wide range and number of physical activity facilities for their students. For the schools, 27% had no indoor facilities and 11% had no outdoor facilities. Private schools and colleges were less likely to have indoor or outdoor facilities compared to public schools. Outdoor facilities were available more often to the public than indoor facilities overall, across sites, and by school type (public, private, college). Among the 313 schools with outdoor facilities, 240 (77%) allowed at least some public use, and among the 210 schools with indoor facilities, 134 (64%) allowed at least some public use. Some reasons that facilities were not made available included: for student use only, supervision and personnel requirements, safety concerns, insurance, liability, and a private or church-owned status. The most common benefits of allowing the public to use the facilities included providing a space to keep youth active and good publicity for the school. CONCLUSION: These findings suggest that safety, insurance, and liability concerns are barriers that need to be addressed with schools before indoor and outdoor facilities can be made available to the public. Furthermore, emphasizing the benefits that we found, such as providing a space to keep youth active and good publicity for the school, would also be important.

Community Participation↗

PubMed2000

[In vitro analysis of the iron availability in fortified rice].

Cereals are rich in fiber but also in phytate which is considered the principal inhibitor of mineral availability. On this basis, iron availability of fortified rice, and the inhibitory effect of bran phytate was studied in: white rice fortified with electrolytic iron (ABF) from commercial origin; and mixtures of ABF plus 4.76% and 9.09% of rice bran (ABF2 and ABF3 respectively) to simulate brown rice. Samples were analysed before and after phytic acid hydrolysis with phytase: Dietary fiber and phytic acid were assessed according AOAC; iron availability, expressed as dialisable iron by the in vitro method of Kapsokefalou and Miller modified by Valencia et al.; iron content was assessed by AAS. Results showed that added bran depressed iron availability, 9.65%; 4.04% and 1.82% as expected (ABF, ABF2 and ABF3 respectively). After phytic acid hydrolysis iron availability reached 28.20%; 27.95% and 25.30% for the same samples. These values were not different. After phytic acid hydrolysis, fiber content of ABF2 and ABF3 were lower than before. However multiple regression analysis of the data showed that fiber had not influence on iron availability and that phytic acid would be the principal responsible of it. These results indicate that brown rice should have a higher level of iron fortification than in white rice or be combined with other foods that improve iron availability as meats, vegetables or fruits.

Dietary Fiber↗

PubMed2001

[State of soil available sulphur and its requirement along Huaihe River region].

This paper investigated the available S contents of yellow cinnamon soil, fluvisol, shajiang black soil and paddy soil, which were developed from loessial ancient-river alluyium, recent loess-flooding deposit, and Xiashu loess. The input and output, and the abundance and deficiency of soil available S were studied in combination with the mode of land utilization and fertization, and the soil demands of S was predicted. The results showed that the content of soil available S was decreased in the order of paddy soil > shajiang black soil > yellow cinnamon soil > fluvisol, and there was more S in irrigated land than in dry field in case of different land utilization. From the viewpoint of parent material, the deficiency frequency of soil available S was in the order of loessial ancient-river alluvium > Xiashu loess > recent loess-flooding deposit, and the potential deficiency frequency of S was loessial ancient-river alluvium > recent loess-flooding > Xiashu loess. As for soil type, the deficiency frequency of soil available S was in the order of deposit shajiang black soil > yellow cinnamon soil > fluvisol > paddy soil, and the potential deficiency frequency of S was paddy soil > fluvisol > shajiang black soil > yellow cinnamon soil. Shajiang black soil had the largest area of lacking available S, which amounted to 7.0 x 10(4) hm2, yellow cinnamon soil had an area of 2.0 x 10(4) hm2, and fluvisol was 6000 hm2. The total area of lacking S was 9.6 x 10(4) hm2, accounted for 25.06% of total cultivated area. The total area of potentially lacking S was 1.6 x 10(5) hm2, accounted for 42.04% of the total. According to the current available S content in soils and the S demands for high yielding crops, the S demands of 3.8 x 10(5) hm2 farmland in three counties and one district of Bengbu was about 3.0 x 10(6) kg and 1.2 x 10(6) kg in the recent and far future, respectively.

Fertilizers↗

PubMed2006

[Arbuscular mycorrhizal fungal growth on citrus roots and its correlations with soil available phosphorus content and phosphatase activity].

In 2004, a field investigation was made on the mycorrhizal infection rate, spore density, soil available phosphorus content, and soil phosphatase activity in the Guoqing No. 1 (Citrus unshiu )/trifoliate orange (Poncirus trifoliata) and Guoqing No. 4 (C. unshiu)/trifoliate orange (P. trifoliata) plantations, aimed to approach the correlations between the arbuscular mycorrhizal fungal growth on citrus roots and the available phosphorus content and phosphatase activity in rhizosphere soil. The results showed that the annual variation of mycorrhizal infection rate and spore density in the test plantations was in "A" shape, while that of soil available phosphorus content and neutral phosphatase activity was in "V" shape. The mycorrhizal infection rate was significantly positively correlated with spore density (P < 0. 01), and negatively correlated with soil available phosphorus content (P < 0.01), indicating that higher spore density and lower soil available ghosphorus content could accelerate the mycorrhizai infection on citrus roots. The pore density was significantly negatively correlated with soil available phosphorus content (P < 0.01) while positively correlated with soil total and neutral phosphatase activity (P < 0.01), suggesting that soil available phosphorus could inhibit the increase of spore density, while soil total and neutral phosphatase activity could stimulate it. The mineralization of soil organic phosphorus in citrus plantations was mainly depended on soil neutral phosphatase activity.

Animals↗

PubMed1984

Estimates of available iron in diets of individuals 1 year old and older in the Nationwide Food Consumption Survey.

Levels of total iron and available iron were estimated in the diets of individuals 1 year and older. The source of data was 1-day dietary recall records from the U.S. Department of Agriculture's 1977-78 Nationwide Food Consumption Survey. Total iron intakes of 1- to 2- and 3- to 5-year-old children were 51% and 77% of their respective RDAs. Total iron intakes of 12- to 50-year-old girls and women averaged only 55% to 61% of their RDA. Total iron intakes of other groups came close to or exceeded their respective RDAs. The proportion of total iron calculated to be available ranged from 6.5% to 8.7%, which is less than the 10% assumption of availability used as a basis for setting the iron RDA. When compared with the RDAs, total iron presented a more favorable picture of dietary iron intake than available iron. In relation to the RDAs, proportions of available iron were consistently lower than proportions of total iron. Available iron was lower than total iron in relation to recommended allowances because less than 10% of total dietary iron was available.

Adolescent↗

PubMed1994

Data availability in reproductive and developmental toxicology.

OBJECTIVE: To characterize the availability of reproductive and developmental toxicology information in the literature and the extent to which such information could produce alarm. METHODS: REPROTOX, a computerized data base, was evaluated as a surrogate for the available literature on reproductive and developmental toxicology. A review of 2528 summaries was performed and information in the summaries evaluated as nonreassuring or reassuring. RESULTS: Information on reproductive or developmental effects was available for about half of the summaries. Availability of information was greatest for pharmaceuticals (75% of summaries contained information) and was lowest for nonpesticide chemicals (36% of summaries contained information). Summaries contained nonreassuring information about two-thirds of the time. Information based on human data was variably available according to type of agent, ranging from a low of 5% of pesticide summaries to 88% of vitamin summaries. CONCLUSIONS: Counseling efforts depend on a literature base in which information is missing half the time and in which animal data may be the only available source of information. Information is available more often for pharmaceuticals than for other classes of agents.

Abnormalities, Drug-Induced↗

PubMed1996

The reported availability of general practitioners and the influence of practice list size.

BACKGROUND: Combined practice list sizes have increased, but larger practice size may be associated with disadvantage to patients. AIM: The aim of the study was to investigate the availability of general practitioners as reported by their patients and the relationship between reported availability and practice list size. METHOD: A one-week questionnaire survey of 8315 patients attending participating practices in West Lothian, Scotland, was conducted. Patients were asked about the arrangements for being seen at that attendance, their perception of doctor availability following an urgent or non-urgent consultation request, and their social and demographic characteristics. The proportion of respondents reporting they could see a doctor the same day following an urgent consultation request or within 2 days following a non-urgent consultation request was determined for each practice. RESULTS: Eighteen out of 26 practices agreed to participate in the study, and an overall response rate of 61% was obtained in the patient survey. Participating practices were representative of all practices in the area with regard to list size; questionnaire respondents were representative of the age profile of participating practices and were representative of the local general population with regard to car and home ownership. There was a wide variation among practices in the proportion of questionnaire respondents who reported that a doctor was available within 2 days following a non-urgent consultation request [mean 60.7 (SE 7.1%)], but less variation for the reported availability on the same day after an urgent consultation request [mean 81.1 (SE 2.3 %)]. A significant negative association was demonstrated between combined practice list size and reported non-urgent or urgent availability. CONCLUSION: Wide variation exists between practices with regard to patients' perceptions of doctor availability, and smaller practices may have advantages in this regard. The feelings and perceptions of patients should be taken into account when planning or reviewing the delivery of primary health care.

Appointments and Schedules↗

PubMed1990

Red cell phenylalanine is not available for transport through the blood-brain barrier.

The possibility that red cell-sequestered amino acids such as phenylalanine are available for transport through the brain capillary wall, i.e., the blood-brain barrier (BBB), in vivo was investigated in the present studies with the carotid artery injection technique. Control studies included the examination of the availability of red cell-sequestered solutes such as phenylalanine or D-glucose to liver cells in vivo using a portal vein injection technique. The results show that red cell-sequestered phenylalanine is not available for transport through the BBB or into rat liver in vivo, but human red cell-sequestered D-glucose is available for uptake by liver following portal injection. Therefore, given favorable kinetics it is possible for red cell-sequestered solute to be available for uptake by tissues. However, in the case of neutral amino acids such as phenylalanine, red cell-sequestered amino acid is not available for transport through the BBB in vivo.

Animals↗

PubMed1994

In vitro availability of iron from cereal meal with the addition of protein isolates and fenugreek leaves (Trigonella foenum-graecum).

In vitro iron availability was determined from a standard cereal meal (C) with and without the addition of protein isolates from bovine milk (BP), groundnut milk (GP) and soybean milk (SP). A second set of studies were done to investigate the potentially available iron from fenugreek leaves per se and the effect of their addition on the available iron from the cereal meal. The potentially available iron from the meal increased from 4.91% to 6.73% on the addition of BP. The next best enhancer was GP (4.91% to 6.17%). Although the addition of SP increased the total iron content of the cereal meal significantly, the percent available iron decreased compared to the other milk proteins. The addition of fenugreek leaves (100 g/meal) to the meal increased the total iron content of the meal significantly (3.24 mg to 9.12 mg) (p < .001), however, the available iron was observed to decrease (4.91% vs 4.34%).

Biological Availability↗

PubMed1993

Evaluation of an in vitro method for the estimation of the selenium availability from cow's milk.

The present study evaluates the application of an in vitro digestion procedure for estimating the selenium (Se) availability from cow's milk. The results obtained by this in vitro method indicate that only a small portion (< 10%) of milk Se can be estimated as available. The available fraction of whole milk (4.7%) was significantly lower compared to the Se availability of skim milk (7.3%). Investigations on the methodology of the in vitro method indicate that the portion of total potentially available Se, determined as total dialysable Se, increases simultaneously with protein digestibility along with the digestion process. Therefore it is concluded that protein digestibility might largely influence the Se availability from milk.

Animals↗

PubMed2006

Heavy metal availability in soil amended with composted urban solid wastes.

A study was performed to evaluate the pH and the availability of Zn, Cu, Mn, Pb, and Ni in soil amended with increasing doses of composted solid wastes, collected in Rio de Janeiro, Rio de Janeiro State and in Coimbra, Minas Gerais State, Brazil. The influence of the time elapsed between compost application to the soil and the sampling of the plant growth substrate (soil + compost) for pH and metal availability analyses was also examined. The availability of heavy metals in the soil, in the compost and in the substrate was evaluated using DTPA solution for metal extraction. The increase of the compost doses added to the soil resulted in the increase of the pH in the substrate. The addition of the compost from the bigger city, Rio de Janeiro, resulted in higher increase in soil pH and available Zn, Cu, Pb, and Ni levels as compared to the addition of the compost from the smaller city, Coimbra. Increasing the time elapsed between the compost application to the soil and the sampling of the mixture resulted in higher available Zn, Cu, Mn, and Pb levels. The addition of the compost from Rio de Janeiro resulted in substrate metal concentrations in the order Zn > Pb > Ni > Cu > Mn and for the Coimbra compost the metal concentrations in the substrate was Zn > Pb > Cu > Ni > Mn. The higher values of pH and available metals obtained for the bigger city were attributed to the greatest metal contamination of its compost.

Biological Availability↗

PubMed1981

Relevance of tryptophan and tyrosine availability in endogenous and 'non-endogenous' depressives treated with imipramine or clomipramine.

This study was performed on 65 depressed in-patients who were included in previously reported trials of imipramine and clomipramine. Before and during treatment, blood samples were collected for estimation of the availability of tryptophan and tyrosine by measurement of their plasma ratios to competing amino acids, and for determination of plasma steady-state concentrations of imipramine, clomipramine and their demethylated metabolites. The patients were classified as endogenous or 'non-endogenous' depressives by means of diagnostic rating scales, and therapeutic efficacy was evaluated by means of the Hamilton rating scales. Neither imipramine nor clomipramine increased the availability of tryptophan or tyrosine. Three biochemical regions were defined: a low region including mostly patients with subnormal availability of both tryptophan and tyrosine, a medium region, and a high region including mostly patients with supernormal precursor availabilities. Endogenous depressives showed about the same biochemical distribution as controls whereas there tended to be a proportionately higher number of 'non-endogenous' depressives within the low region. Patients in the low region, irrespective of diagnostic classification, improved faster and more on imipramine than patients in the medium and high regions with comparable plasma drug levels. Patients on clomipramine tended to show a relationship between precursor availabilities and clinical response but no definite conclusion could be drawn from these data. The results suggest that determination of the pre-treatment tryptophan and tyrosine availability may be superior to diagnostic classification in predicting response to imipramine. The possible mode of action of tricyclic antidepressants is briefly discussed.

Biological Availability↗