Immediate response of 5-methoxytryptophol in the circulation to hypoglycaemic stress induced by insulin.

Pineal indoles have been shown to affect the release of anterior pituitary hormones but details of the interrelationships are lacking. Using a new gas chromatography-mass spectrometry (g.c.-m.s.) assay the concentration of 5-methoxytryptophol (ML) was measured in plasma samples obtained from 16 children undergoing investigation of pituitary function for delayed growth. All the children received an insulin tolerance test (ITT) to study their endocrine response to stress. Some children received luteinizing hormone releasing hormone (LH-RH) and/or thyrotrophin releasing hormone (TRH). The change in concentration of ML during an ITT was similar to the change in concentration of blood sugar; a drop at 20 min followed by a rise at 30 min. This was not significantly altered by the administration of LH-RH or TRH, nor was there a different pattern of response in children who were deficient in growth hormone as opposed to those with idiopathic delayed growth. The fall in concentration of ML with stress may mediate the increased secretion of pituitary hormones. Alternatively, the pineal gland may respond directly to insulin.

A sensitive and specific assay for 5-methoxytryptophol in plasma.

5-Methoxytryptophol (ML) is found in the pineal gland and is known to have biological activity especially as an antigonadotrophic agent, but methods have been lacking for its measurement in the circulation. A gas chromatography-mass spectrometry assay using a trimethylsilyl derivative has been developed for the routine measurement of ML in plasma. The assay is of great specificity and has a sensitivity of 20 pmol/l. Studies on the levels of pineal indoles in the circulation, however, have been hampered by the possibility that extraneous compounds are being cross-measured. Thus the specificity of the routine assay has been further validated by comparing it with an alternative assay system where all the major parameters were changed, i.e. derivatizing reagent, internal standard and mass number. Results that were obtained using both assay systems were closely comparable.

Changes in the concentration of 5-methoxytryptophol in the circulation at different phases of the human menstrual cycle.

The pineal indole 5-methoxytryptophol (ML) has been shown to have an antigonadal activity when administered to experimental animals, but data on its normal pattern of secretion have been lacking. Using a new gas chromatography-mass spectrometry assay, the concentration of ML at various phases of the human menstrual cycle has been studied. Daily samples were obtained throughout the month from five women with a normal cycle and two women taking an oral contraceptive. In women with a normal cycle levels of ML were found to be significantly lower in the last third of their cycle; this change was not seen in women taking an oral contraceptive who had low levels throughout the month. The changes in concentration of ML did not correlate with the changes in concentration of gonadotrophins.

Concentration of 5-methoxytryptophol in pineal gland and plasma of the rat.

5-Methoxytryptophol, a serotonin metabolite, was measured by gas chromatography-mass spectrometry in pineal glands, plasma and control tissues (cerebral cortex and salivary glands) from male rats kept in a controlled lighting environment. In the pineal gland the level of 5-methoxytryptophol was significantly higher during the dark period than during the light, the absolute levels being an order of magnitude less than those of melatonin. In the plasma, the levels showed a reverse situation with respect to lighting conditions. No correlation was found between the 5-methoxytryptophol levels in plasma and the pineal gland in individual animals. These results suggest that there is no obvious correlation between pineal content and pineal activity. This may be due to a combination of rapid turnover, secretion and/or peripheral conversion of another 5-methoxyindole to 5-methoxytryptophol.

Excitatory effects of oxytocin and cholecystokinin on oxytocin neurones: differences between virgin, pregnant and lactating rats.

Extracellular recordings were made from supraoptic oxytocin (OT) neurones in rat brain slices to investigate the effect of reproductive state on their excitation by OT and cholecystokinin (CCK). Stable background activity was induced by local glutamate application, and OT neurones were identified by their continuous firing and opioid inhibition. The excitatory effect of OT (indicated by percentage neurones excited, peak increment in firing, and response magnitude) was maximal in lactating rats, intermediate in virgin, and lowest in pregnant animals. Excitation by CCK was high in both lactating and virgin rats but, as with OT tests, was minimal in the pregnant group. These adaptations in the responses to OT and CCK may help to ensure that the firing of OT neurones is appropriately regulated to meet changing demands for OT release.

Non-aqueous capillary electrophoresis of tamoxifen and its acid hydrolysis products.

Tamoxifen and its acid hydrolysis products were separated and tentatively identified by non-aqueous capillary electrophoresis with thermooptical absorbance and electrospray ionization mass spectrometry. Acid hydrolysis is a convenient method of generating tamoxifen degradation products. The parent compound and seven hydrolysis products were separated in 9 min.

Comparison of impedance at the microelectrode-saline and microelectrode-culture medium interface.

The impedance characteristics of gold-plated indium-tin-oxide microelectrodes immersed in culture medium (MEM) are described and compared with the impedance characteristics observed when those microelectrodes are immersed in isotonic saline. For microelectrode areas of approximately 100 microns2, applied voltage levels of 5, 50, and 100 mV, and for frequencies of from 100 Hz to 10 kHz the resistance, capacitance, capacitive reactance, and total impedance are given as a function of frequency both in culture medium and in saline. The results, which hold for current densities ranging from 0.45 to 700 pA/microns2, are compared. Also given are the alpha and K values determining the frequency characteristics of the interface resistance and capacitance in medium and in saline.

Measurement of human exposure to ultraviolet-B solar radiation using a CR-39 dosimeter.

CR-39 (allyl diglycol carbonate) dosimeters were tested for measurements of ultraviolet-B (erythemal dose) solar radiation with a rotating model head and a human survey during solar exposure. The ratio of summer dose to winter dose for the vertex is 3.3, and for the eye and lower face is greater than 1. A survey suggests the relation of the ultraviolet-B dose to outdoor activities.

The little finger.

For most people, the fifth finger--the gripping finger--is probably second in importance only to the thumb. Emergency room personnel should not be too ready to sacrifice this finger to satisfy the needs of other damaged digits.

Limits to wideband pulsed squeezing in a traveling-wave parametric amplifier with group-velocity dispersion.

A theoretical method is developed to treat wideband pulsed squeezing in a traveling-wave parametric amplifier with group-velocity dispersion. Classical stochastic wave equations that are fully equivalent to operator equations of motion are developed and solved numerically. It is found that squeezing occurs over the entire phase-matching bandwidth, although the degree of squeezing decreases when the pump-pulse duration is shorter than the inverse of this bandwidth.

Time dependence of quantum fluctuations in solitons.

We investigate quantum fluctuations in coherent solitons propagating in a dispersive nonlinear waveguide. Optimal squeezing or noise reduction occurs for a local oscillator width near the soliton width in time, i.e., the quantum fluctuations are localized.

A study of job turnover among clinical laboratory personnel.

A study of job turnover in clinical laboratories in the Minneapolis-St. Paul area was conducted in the years 1970, 1975, and 1980. Annual turnover rates for all laboratory personnel were 20%, 19% and 15% respectively. The groups with the lowest turnover were cytotechnologists, histologic technicians and clinical laboratory scientists (medical technologists). The highest turnover occurred among clinical laboratory technicians and "others," primarily supportive personnel such as phlebotomists, assistants, and aides.

Ultrasonic evaluation of radiation therapy ports.

Radiation therapy is useful in the palliative treatment of large, unresectable abdominal and pelvic malignancies. The purpose of this study is to evaluate the effectiveness of B mode ultrasound scanning as an adjunct in radiation treatment planning of these patients. Fifty-one patients with large abdominal or pelvic masses had radiation therapy ports established using findings from surgery, radiographs, and physical examination. All the patients then had B mode ultrasound examinations. The position of the therapy ports was marked on the echogram. Thirty-one of the 51 patients studied (61%) had evidence of extension of tumor beyond the therapy ports. This was often due to "iceberging", i.e. when the deep portion of the tumor was considerably larger than the palpable margins of the superficial portion. B mode ultrasound scanning is a valuable adjunct in planning palliative radiation therapy of patients with large, unresectable, abdominal and pelvic malignancies.

Papillary adenoma of the gall bladder: ultrasonic demonstration.

A papillary adenoma of the gall bladder was demonstrated by gray scale echography. The pathology of the tumor was described and the ultrasonic characteristics which distinguish it from a calculus were discussed.