Case-fatality rates in severe measles outbreak in rural Germany in 1861.
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Adolescent↗
Biomedical subjects
K Dietz
Publications and source records attributed to K Dietz.
[Current vaccination strategies].
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AIDS Vaccines↗
[Quantitative analysis of recurrence and spontaneous regression of basalioma parts left in situ].
To some extent, parts of basalomas found remaining in situ following tumour excision tend to spontaneous regression. This is a well-known phenomenon and has significance for the recurrence of incompletely excised tumors. The present study involved a quantitative investigation of the relationship between recurrence and spontaneous regression. Following precisely defined excision of basalomas, the entire exterior of the excised material was examined by contrast microscopy in HE-stained paraffin sections (3-dimensional histology). Whenever tumour outgrowths were found, it was possible to document exactly their type, localization, extent, and depth of invasion. In 66 such cases no follow-up operation was performed, but only a follow-up examination after a minimum of 31 and a maximum of 113 months (average: 60 months). Only 50% of these undisturbed tumour outgrowths resulted in a recurrence during the follow-up period. A very high rate of spontaneous regression (71%) was found among the solid tumour outgrowths, but a significantly lower rate (19%) among the fibrosing tumours. Moreover, regression was dependent on the tumour remnant's mass and the clinical diameter of the tumour removed. It was independent of the depth of infiltration. Although the rate of spontaneous regression of tumour outgrowths persisting after therapy is relatively high, it cannot be predicted in individual cases. It is not possible to be certain that tumour removal has been achieved unless micrographic surgery has been continued until complete absence of tumour is proved. In all procedures that are not subsequently monitored, an unacceptably high rate of recurrence must be expected, especially in the case of fibrosing basaloma. This is commented on at length.
Aged↗
[Extrahepatic bile duct atresia. Comparison of surgical and non-surgical therapy].
In recent years hepatoportoenterostomy according to Kasai undoubtedly was the only successful therapy for extrahepatic biliary atresia. Since liver-transplantation becomes more successful than previously, the question arises if the Kasai procedure is still justified. From this point of view a prospective study was started based on the following findings in 15 EHBA-children after hepatoportoenterostomy compared to those in 15 patients without the Kasai procedure: the survival rate at the end of two years of life; the development of ascites until the end of the first year of life; the weight and length percentiles at the end of the first year of life; and the activity of serum cholinesterase. In order to calculate significant differences in weight and length percentiles, the exact Fisher test was used. Serum cholinesterase activities of both the above mentioned groups were compared with each other, as well as with the normal values of a third group of 50 healthy children, by analyzing variances and then comparing one by one with adjustment for multiple comparisons. There was a significant difference between the operated and not-operated group, and in addition between the non-operated and the healthy group. In contrast, no significant difference was detected between the operated and the healthy group. These differences were best demonstrated by the findings of weight and length percentiles and the activity of serum cholinesterase. From this we conclude sofar hepatoportoenterostomy undoubtedly is standard procedure in the treatment of EHGA. However, if the Kasai procedure fails or the liver disease progresses to a greater extent, liver transplantation will become the method of choice.
Biliary Atresia↗
[Statistical approach to forensic conversion values for alcoholics].
With collaboration of the study groups from Tübingen, Munich and Kiel and consideration of the results of Bonnichsen et al 1968, alcohol elimination curves of 98 alcoholics were subjected to a joint evaluation for determination of the beta 60 values. The average elimination rate was 0.21 g/kg/h (s = 0.05 g/kg/h). By analogy to average beta 60 values and back-conversion factors of nonalcoholics, the limit values for alcoholics were estimated as being between 0.12 g/kg/h (minimum value) and 0.29 g/kg/h (maximum value).
Adult↗
Seroepidemiological correlations of antibodies to human herpesviruses and human immunodeficiency virus type 1 in African patients.
A seroepidemiological evaluation of the humoral immune response against human herpes viruses was carried out in patients with and without HIV infection in Tanzania to study the role of these viruses as a cofactor in AIDS. Serum specimens were obtained from 321 outpatients and 100 healthy schoolchildren of a rural population in the Kagera Region, Tanzania, and from 149 inpatients of an urban population in Dar-es-Salaam, Tanzania. The data were analysed by logistic models taking into account demographic variables. The data obtained revealed no differences in the prevalence of antibodies to human herpes viruses between the different groups. Therefore, our study under the present conditions and the observed stages of AIDS does not suggest an influence of HIV infection on human herpesvirus infection or serologic response.
Acquired Immunodeficiency Syndrome↗
The basic reproduction ratio for sexually transmitted diseases: I. Theoretical considerations.
It is shown how one can calculate the basic reproduction ratio R0 for infectious disease models where an arbitrary but finite number of disease states are recognized and where the phenomena of pair formation and separation are taken into account. Several examples are discussed.
Female↗
Prediction of subclinical tumor infiltration in basal cell carcinoma.
Two thousand-sixteen basal cell carcinomas (BCCs) were documented in terms of age, anatomic location, tumor diameter, initial excision depth, safety margin, histologic type, and the position of tumor outgrowths as determined by three-dimensional histologic study of the tumor margins in paraffin sections (micrographic surgery). The extent of each subsequent excision was recorded until tumor-free tissue was reached. The results showed that BCCs have a highly irregular infiltration pattern and a predilection for small, fingerlike outgrowths whose bases occupy 1-30 degrees of the tumor circumference. When superficial extension was expressed mathematically, the resulting exponential functions varied highly significantly (P = .001) according to histologic tumor type and diameter. The resulting curves permitted very precise prediction of the probability of tumor-positive margins (ie, subtotal excision), depending on the safety margin, histologic tumor type, and tumor diameter. For example, the probability of tumor-positive margins after excision of a BCC up to 10 mm in diameter is 30% with a safety margin of 2 mm, 16% with a safety margin of 3 mm, and 5% with a safety margin of 5 mm. The probability of tumor-positive margins for fibrosing primary BCCs 10-20 mm in diameter is 48, 34, and 18% with safety margins of 2, 3, and 5 mm, respectively. Recurrent tumors have a significantly higher probability of positive margins (P = .001) than primary ones. Anatomic location and tumor age affect subclinical extension only indirectly.
Basal Cell Carcinoma↗
Mathematical models of myosin heterodimer formation in the rat heart during thyroid hormone alterations.
To characterize the mechanisms involved in the formation of the myosin heavy chain (MHC) heterodimer V2 (alpha beta-MHC) and the homodimers V3 (beta beta-MHC) and V1 (alpha alpha-MHC), 82 5-week-old normotensive rats with homogeneous V1 were made hypothyroid with propylthiouracil (0.8%, drinking water), and the proportion of V2, V3, and V1 was determined by pyrophosphate gel electrophoresis in multicellular specimens of the left and right ventricles. After the switch from alpha-MHC to beta-MHC, the beta-MHC occurred initially in the form of the heterodimer. After 4 and 6 days, V2 was greater (p less than 0.05) than V3. At day 8, V2 was smaller than V3, and at day 10, V2 was not statistically different from V3. From day 12 onward, V2 was smaller than V3. After 21 days, the propylthiouracil treatment was stopped, and the remaining 34 hypothyroid rats were injected with a daily dose of thyroxine (average, 0.1 mg/kg body wt), resulting in a switch from beta-MHC to alpha-MHC. After 1 day, V2 still was greater than V1; however, already from day 3 onward, V2 was smaller than V1. This characteristic but unexplained heterodimeric and homodimeric organization of the thick filament was analyzed by mathematical models involving probability calculations. Two principally different models were established that assume either the exchange of MHC dimers or of single MHC in the thick filament. The parameters of the models were estimated by minimization routines using the squared discrepancies between the experimental and predicted isoenzyme populations. Based on goodness of fit and crucial model parameters, we concluded that the characteristic organization of the thick filament can be accounted for by an exchange involving predominantly MHC dimers and not single MHC. The fact that V2 was lower than expected if formation of heterodimers and homodimers were random was attributed to the preferred homodimerization of 35% of the newly synthesized MHC.
Animals↗
[Locally infiltrative growth of squamous cell carcinoma of the skin and treatment guidelines resulting from it].
The infiltrative growth behaviour of squamous cell of the skin carcinomas is characterized by subclinical outgrowths, very frequently extending horizontally and sometimes over long distances. They are presented in the form of a negative exponential function. These outgrowths have an irregular pattern. It is much more extensive in the case of tumours with a clinical diameter of more than 20 nm. All types of "blind" therapy such as cryopexy, irradiation, laser, and surgery monitored in only two dimensions involve an inevitable risk of recurrences, which can be calculated statistically from the results available. Routine histographical surgery of skin carcinomas in the form of continuous, 3-dimensional histology can dramatically reduce the risk of local relapse, especially in the case of small and medium-sized carcinomas. The test group presented here (411 carcinomas) was treated with histographic surgery using the paraffin section method; during the follow-up period (maximum: 7 years, minimum: 3 years) the danger of recurrence was 2.2% for all carcinomas but only 0.6% for those up to 20 mm in diameter (n = 340). Carcinomas with a diameter of more than 20 mm (n = 71) involved a much higher risk of recurrence with 9.8%. This is probably because of local micrometastases, which require more generous local excision with a safety margin of about 10 mm.
Carcinoma, Squamous Cell↗
[The subclinical portion in the periphery of lentigo maligna and lentigo maligna melanoma].
Lentigo maligna is a precancerosis or a melanoma in situ, whose level of malignancy has not yet been definitively clarified. Recurrences are not rare after excision, even when an ample safe margin is observed. One reason for this is the existence of a subclinical ramification in the marginal area of the lentigo maligna. Such subclinical ramifications were investigated by means of excision with histological monitoring of the margins by the paraffin section technique. There was a clear relationship between the frequency of these ramifications and the clinical safe margin left in 64 excisions. With the aid of parametric evaluation methods the distribution of the subclinical portion referred to the distance from the clinical margin could be determined with a special formula. If an invasion, in the form of a lentigo maligna melanoma had already taken place, then the subclinical portion within the marginal area was significantly more extensive. For the treatment of lentigo maligna, and especially of lentigo maligna melanoma, we therefore recommend excision with histological monitoring of the margins. There were no local recurrences within an average follow-up period of about 2 1/2 years.
Adult↗
Epidemiologic interference of virus populations.
There are a few simulation studies for interference models in the literature but the present paper discusses an analytical model for the competition of two interfering virus populations in a community. The mathematical model consist of eight coupled differential equations which have up to four equilibrium points. Criteria for local stability are given.
Disease Outbreaks↗
Antibody against hepatitis A in seven European countries. II. Statistical analysis of cross-sectional surveys.
The age-specific prevalence of hepatitis A antibodies has been analyzed using a catalytic epidemic model for populations in seven European countries: West Germany, Norway, Greece, Switzerland, Holland, France and Sweden. The results indicate a significant decline in the force of infection in recent decades. However, there are substantial differences between the countries, especially between the Scandinavian countries and Greece. The incidence of hepatitis A in Norway and Sweden has declined since 1930, while a downward trend in incidence in Greece may have started only recently.
Adolescent↗
Further epidemiological evaluation of a malaria model.
The malaria model previously fitted to 1 year of baseline data from the Garki District in the Sudan savanna of northern Nigeria was tested against data collected in the same area over a period of 3 years, including 1(1/2) years during which the insides of houses in certain villages were sprayed with propoxur. It was also tested against data collected in Kisumu, Kenya, also over a period of 3 years, including 20 months during which the insides of houses in part of the area were sprayed with fenitrothion. The test consisted in using the vectorial capacity, calculated from the entomological observations made in the above places and periods, as input in the Garki model while keeping the other parameters as fitted to the Garki baseline data, and in comparing the prevalence of Plasmodium falciparum parasitaemia as estimated by the model to that actually observed. There was relatively good agreement and the model is considered epidemiologically satisfactory and fit for use in planning malaria control operations.
Adolescent↗
[Frequency of hepatitis A antibodies in populations of various European countries].
Using a solid phase radioimmunoassay, prevalence of anti-HA was determined in sera of 661 German patients treated following accidents, 70 persons born in Mediterranean countries and 175 persons from Lillehammer, Norway. In Germany (55% positive) an increase in prevalence of anti-HA from 13% in the group below 20 years of age to 92% in persons over 49 was noted. This and further data suggest that after infection anti-HA is detectable for life. Persons from Norway (17% positive) aged below 40 years had a low prevalence of anti-HA (4-10%), whereas even young persons from Mediterranean countries (81% positive) hat antibody in about 80% of cases. Prevalence rates in different age groups suggest a remarkable decrease in incidence of hepatitis A infection over the last three decades in Germany. This results in a rise in the mean age at which hepatitis A infection is acquired and high morbidity during travel abroad. Only one of 10 hepatitis A infections appears to produce clinical disease. Young anti-HA positive individuals exhibit higher titers on average than older ones.
Adult↗
The effect of immigration on genetic control.
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Female↗
Comparative field cage tests of the population suppressing efficiency of three genetic control systems for Aedes Aegypti.
Cycling populations of Aedes aegypti were set up in cages and managed in such a way that the populations had a maximum of threefold recovery potential in response to control measures. Into three such populations daily releases were made of males which had been chemosterilised, or were double translocation heterozygotes (T1T3) or T1T3 with sex ration distortion (DT1T3). Eradication of the populations was achieved with all cases, but the rate of suppression was markedly slower with T1T3 than the other two systems, with which the rates were similar. T1T3 and DT1T3 releases introduced considerable inherited genetic loads into the target populations. The results were in general agreement with computer predictions.
Aedes↗
The impact of propoxur on Anopheles gambiae s.1. and some other anopheline populations, and its relationship with some pre-spraying variables.
A significant and stable difference in the residual night-biting collection (NBC, observed/expected) of A. gambiae s.l. was observed among different villages of the West African savannah when sprayed for 2 years with propoxur. The residual mosquito density of a given village was positively associated with some of its pre-spraying characteristics: the NBC/PSC (pyrethrum spray collections) ratio, the median biting hour, and possibly the proportion of species B. It was not significantly associated with several other pre-spraying characteristics (absolute mosquito density, the ratios between NBC indoors and NBC outdoors, between ETC (exit-trap collections) and PSC, between fed and gravid in the PSC or ETC, between males and females in the PSC), and was not associated with variations in recorded coverage, with latitude, or with distance from unsprayed villages.In a comparison between A. gambiae s.l., A. funestus, and A. pharoensis, the residual NBC (observed/expected) was positively associated with the pre-spraying NBC/PSC ratio, and was negatively associated with the median biting hour.The pre-spraying NBC/PSC ratio thus appears to be a predictor of the variation, between villages or species, in the reduction of the NBC by residual spraying, and may assist in forecasting the effect of a residual insecticide. The limitations of any absolute prediction must, however, be kept in mind.
Animals↗