Respiratory depression in goats by stable xenon: implications for CT studies

The pharmacology of stable xenon is of practical importance to users of the xenon CT-regional cerebral blood flow method. In a study in goats we have demonstrated that xenon has a characteristic respiratory depressant effect, unlike effects of comparable anesthetic concentrations of nitrous oxide and halothane.

Comparison of characteristics of human small cell carcinoma of the lung in patients, in vitro and transplanted into nude mice

Specimens from 24 patients with metastatic small cell carcinoma of the lung were explanted in vitro as well as transplanted directly into nude mice. A method to obtain fibroblast-free cultures is described. This method resulted in cell lines which could be grown for more than one year in 79% of the cases. Fifty-four % of the tumours could be established as serially transplantable tumours in nude mice. The tumours were characterized by histology, electron microscopy, DNA index, and cell cycle distribution. The in vitro cell lines were furthermore characterized by the plating efficiency and by doubling time. The macroscopic growth of the heterotransplanted tumours was ascribed to a transformed Gompertz function. The tumour cells preserved their light microscopic constitution of small cell carcinoma of the lung in the model systems. The heterogeneity of the original tumours was reflected in vitro and in nude mice and the model systems thus allows an expression of the inherent heterogeneity and instability. The panel of transplantable tumours and the in vitro cell lines offer the study of biology inclusive of tumour progression of SCCL.

Serum steroid levels in intact and endocrine ablated BALB/c nude mice and their intact littermates

An investigation was made of the serum steroid levels found in intact and endocrine ablated nude mice of both sexes and in their intact homozygous littermates. The results showed that nude mice have a normal steroidogenesis, but with decreased levels of circulating steroids compared to those of the littermates. The efficacy of the endocrine ablations was confirmed by the reduction in serum oestrone following oophorectomy, and by the reduction in serum testosterone and progesterone following orchiectomy. The normal steroidogenesis in nude mice, and the similarities between mouse and man with regard to changes in serum steroids following oophorectomy and orchiectomy, support the usefulness of human tumor xenograft models for the study of hormone-tumor interactions.

Number of "high genes" involved in determining the activity of paraoxonase

The genetics of paraoxonase activity is further analysed on the basis of a Danish family material (Eiberg & Mohr 1981), namely a random sample of the investigated two mating types. The starting point is the earlier assumption that the segregation into high and low activity is due to alleles on a single locus with the frequency 0.726 of low genes (Eiberg & Mohr 1981, Nielsen et al. 1986). It is shown that a hypothesis of two "high genes", h1 and h2 on the same locus, with allele frequencies 0.117 and 0.157, both high genes being dominant over low genes and h2 dominant over h1, may explain the observed pattern of segregation. The hypothesis would imply average activities of genotype 1h1 of 960 microM PNP/1, of 1h2 1385 microM PNP/1, of h1h1 1202 microM PNP/1, and of h1h2 and h2h2 2048 microM PNP/1. It cannot be excluded that there are more than two "high genes". It is further shown that more than one "low gene" must be involved.

Long-term follow-up of von Recklinghausen neurofibromatosis. Survival and malignant neoplasms

To document the natural history of von Recklinghausen neurofibromatosis, we followed up a nationwide cohort of 212 affected patients and families identified in Denmark 42 years ago. We obtained follow-up information on 99 percent. Because all 76 probands were identified through hospitals, they may include a disproportionate number of severe cases of neurofibromatosis. To diminish this effect of selection bias, we distinguished between the probands and their affected relatives. In a comparison with the general population, survival rates were significantly impaired in relatives with neurofibromatosis, worse in probands, and worst in female probands. Malignant neoplasms or benign central nervous system tumors occurred in 45 percent of the probands, giving a relative risk of 4.0 (95 percent confidence limits, 2.8 to 5.6) as compared with expected numbers. Multiple primary neoplasms were found in 15 probands, but only 1 relative. Compared with the general population, male relatives with neurofibromatosis had the same rate of neoplasms, whereas female relatives had a nearly twofold higher rate (relative risk, 1.9; 1.1 to 3.1). Nervous system tumors were disproportionately represented. We conclude that patients with severe neurofibromatosis requiring hospitalization often have a poor prognosis, but incidentally diagnosed relatives may have a considerably better outcome.

Number of loci responsible for the inheritance of high and low activity of paraoxonase

On the basis of a Danish family material of Eiberg & Mohr (1981), especially 416 matings with 1595 children where the one parent has high activity of paraoxonase and the other low activity, and the 185 matings with 684 children where both parents have high activity, it is, by consideration of a two-loci model and other alternatives besides the earlier suggested one-locus model, confirmed that segregation into high and low activity is largely or exclusively due to a one-locus system; in case any secondary locus is involved, its most common allele would probably have a frequency above 0.95.

Onset of the release of spermatozoa (spermarche) in boys in relation to age, testicular growth, pubic hair, and height

The onset of production of spermatozoa (spermarche) is the basis for achievement of reproductive capacity in men. We collected 24-h urine samples every 3 months in a 7-yr longitudinal study of 40 normal boys initially aged 8.6-11.7 yr. After centrifugation, the urine was analyzed for the presence of spermatozoa by microscopic examination, and spermarche was estimated on the basis of age at first observed spermaturia. The results were corrected for the intermittent occurrence of spermatozoa in the urine after first observed spermaturia and the fact that the urine samples were collected quarterly. In addition, physical examination, including determination of testicular size by orchidometer measurement, pubic hair distribution (Tanner stage), and height, was carried out every 6 months. Spermarche occurred at a median age of 13.4 yr (range, 11.7-15.3 yr), at a time when testicular size was 4.7-19.6 ml (median, 11.5 ml), and pubic hair distribution was 1-5 (median, 2.5). In most boys, spermarche preceded the age of peak height velocity (median, 13.8 yr; range, 12.2-15.2 yr); at the time of spermarche, median peak height growth velocity was 9.9 cm/yr (range, 7.5-13.4 cm/yr), and median height was 160.4 cm (range, 151.7-175.9 cm). We conclude that spermarche is an early pubertal event and that a wide variation in testicular size and secondary sex characteristics is found at that time. In particular, spermarche may occur when little or no pubic hair has developed, and the testes have grown only slightly.

Characterization of the T61 human breast carcinoma established in nude mice

This paper gives a biological characterization of the T61 human breast carcinoma established in nude mice. The human origin of the tumour was verified by the demonstration of the presence of human chromosomes exclusively in the tumour cells. The tumour cells were found by chromosome analysis and flow cytometric DNA analysis to be aneuploid. By electron microscopy, the tumour cells were shown to display the characteristics of glandular epithelium; a light microscopic examination revealed morphological characteristics similar to those of an axillary metastasis of the patient from whom the T61 tumour was derived. Furthermore, the tumour was shown to contain classical receptors for oestrogen and progesterone. The growth of the tumour was characterized by gompertzian growth curves. Since the T61 tumour has a response pattern to endocrine treatment which differs from that described for other human breast tumours grown in nude mice, this tumour may provide a valuable supplement in the study of human breast cancer and endocrine treatment.

Endocrine sensitivity of the receptor-positive T61 human breast carcinoma serially grown in nude mice

A study was made on the effect of ovariectomy, 17 beta-oestradiol, and tamoxifen on the oestrogen and progesterone receptor-positive T61 human breast carcinoma grown in nude mice. The effect of the treatment was evaluated by the specific growth delay calculated on the basis of Gompertz growth curves, and by the changes in the cell cycle distribution monitored by flow cytometric DNA analysis. The results demonstrated that both oestradiol and tamoxifen induced a temporary growth delay, whereas ovariectomy of the host had no effect on the growth of the tumour. The oestradiol-induced tumour growth delay was accompanied by a decrease in the G1 fraction, an accumulation of cells in the S-phase, and polyploidy, whereas neither treatment with tamoxifen nor ovariectomy influenced cell cycle distribution. The results indicate that oestradiol and tamoxifen have different mechanisms of action. In addition, they were interpreted as indicating different mechanisms regulating ovarian-dependent tumour growth, on the one hand, and oestrogen and tamoxifen-induced tumour growth inhibition, on the other. The results support the view that the presence of receptors may be of importance but is not a sufficiently clear marker to allow prediction of the endocrine sensitivity of individual breast tumours.

Quantitative influence of serum creatine kinase isoenzyme MB estimated infarct size and other prognostic variables on one year mortality after acute myocardial infarction

The aim of the present study was to determine the strength of the relation between serum creatine kinase isoenzyme MB estimated infarct size, other prognostic variables, and mortality after acute myocardial infarction. Serum creatine kinase MB estimated infarct size and 11 other prognostic variables were obtained in 317 patients. By Cox regression analysis the prognostic variables significantly related to mortality were identified: congestive heart failure, estimated infarct size, New York Heart Association class, number of previous infarcts, and age. Congestive heart failure and estimated infarct size were most strongly related to mortality. The relation between the prognostic variables and mortality was non-linear, and the variables influenced each others' relation to mortality. A prognostic index based on all five prognostic variables provided the best means of estimating the probability of survival after acute myocardial infarct. Neither serum creatine kinase MB estimated infarct size nor any of the other prognostic variables had a significant independent influence on mortality, and the probability of survival was high in the absence of any of the prognostic variables in combination.

The Mini-Cap. External immobilization of facial fractures

A method is described for external immobilization of the facial skeleton. The method is only indicated in a few cases. By means of Vitallium screws and a small head cap of plaster of Paris it is possible to achieve stiff, external immobilization of facial fractures, even when they are situated in the frontal bones. The Mini-Cap permits the patient to rest comfortably and costs very little.

Dose-dependent effect of 17 beta-estradiol determined by growth curves and flow cytometric DNA analysis of a human breast carcinoma (T61) grown in nude mice

An estrogen and progesterone receptor-positive human breast carcinoma (T61) grown in nude mice was exposed to 1.0, 0.1, 0.01, and 0.001 mg 17 beta-estradiol. These doses resulted in serum peak concentrations (day 1) of estradiol ranging from 3.5 X 10(-8) to 6.9 X 10(-10) M. The effect of the treatment was evaluated using growth curves and flow cytometric DNA analysis. The treatment induced a dose-dependent growth delay and dose-dependent changes in the cell cycle distribution. The cell cycle changes comprised a decrease in the G1 phase, an accumulation of cells in the S phase, and an increasing fraction of polyploid cells. The results suggest that estradiol induces a dose-dependent cell killing effect in the T61 human breast carcinoma. The correlation between the treatment-induced growth delay and the effect on the cell cycle distribution indicates that the changes in the cell cycle are a reflection of the estradiol-induced cell destruction. Since no tumor growth stimulation could be observed even at very low serum estradiol concentrations, the T61 human breast carcinoma may represent a new aspect in the study of human breast cancer.

Patency of the maxillary sinus ostium in healthy individuals

In a group of 20 healthy subjects the patency of the maxillary ostium has been evaluated in 35 maxillary sinuses with three different techniques: simultaneous pressure recording in the sinus and the ipsi- and contralateral nasal cavity; simultaneous recording of differential pressure between the sinus and the ipsilateral nasal cavity and air-flow through the ostium during nasal breathing; recording of the pressure rise in the sinus with an artificial air-flow of 1 litre per minute applied to the sinus. The tests were carried out in sitting and recumbent positions. In 5 persons (10 sinuses) a retest was performed after 2 months. These subjects were also tested with an inflatable neck cuff in order to obtain an increased venous pressure. Rhinomanometry at rest and after physical effort was also performed. The pressure relationship between the maxillary sinus and the ipsilateral nasal cavity was 1:1 in both the sitting and the recumbent position, but less than 1 when the contralateral nasal cavity was measured. Pressure recording alone gives no quantitative information about the patency of the ostium. Determination of the ostial resistance during nasal breathing could be performed in 13 sinuses, but in the remaining 22 the ostia were too wide to give a measurable resistance. The equivalent ostial diameter during inspiration could be estimated in 12 of the sinuses from a diagram constructed from known ostial diameters in model experiments. With an artificial air-flow applied into the sinus, the equivalent ostial diameters could be estimated from the diagram in all cases. No statistical difference was found in comparable cases between the mean equivalent ostial diameters estimated with the two methods. The equivalent ostial diameters showed a statistically significant reduction in the recumbent position and after application of the neck cuff. A statistically significant relationship was also found between the airway resistance of the nasal cavity and the equivalent diameter of the ostium in sitting and recumbent positions. Such a relationship could not be found between the equivalent ostial diameters measured at rest and the nasal resistance recorded after physical effort.

Effect of 17 beta-oestradiol on growth curves and flow cytometric DNA distribution of two human breast carcinomas grown in nude mice

The effect of 17 beta-oestradiol on a "receptor positive" and on a "receptor negative" human breast carcinoma grown in nude mice was studied. Experimental growth data were used to determine the effect on tumour growth. Flow cytometric DNA analysis (FCM) performed on tumour tissue obtained by sequential fine-needle aspirations was used to estimate the effect on the cell cycle. In the receptor-positive breast carcinoma, oestradiol induced complete tumour regression and characteristic cell cycle changes. In the receptor-negative breast carcinoma, no changes in tumour growth and cell cycle distribution could be demonstrated following the treatment. The results indicate that the oestradiol-induced cell kill could be explained to some extent by the induction of polyploid cells, which eventually die. Since the cell cycle changes monitored by FCM in the receptor-positive breast carcinoma appeared prior to any reduction in the tumour size, the results suggest that FCM may prove a valuable method in the early detection of tumour response to hormone treatment in human breast cancer.