Concentration distribution of more than 100 drugs and metabolites in forensic hair samples.

Drug testing in hair can complement conventional blood and urine analysis as it enlarges the window of detection and may allow a differentiation of heavy from moderate or rare use. Databases of drug concentrations in biological matrices are a valuable support in interpreting analytical results. In forensic toxicology, several databases exist especially for blood/serum samples. In the present paper, the concentration distributions of more than 100 legal and illegal drugs such as narcotic drugs, opioids, antidepressants, antipsychotics, benzodiazepines, and major metabolites detected in authentic Caucasian hair samples in our laboratory are summarized. Depending on availability, the proximal sections of 1-6 cm in length were analyzed by liquid chromatography/tandem mass spectrometry following extraction of the finely chopped specimens by ultrasound in methanol. The data may present a helpful basis also for other laboratories for an initial evaluation of their results. However, these statistical data should not be used uncritically without including the circumstances of the particular case and the analytical procedures used. In addition, each laboratory in charge of interpreting results from hair analysis should balance own results as far as available with this data base.

[The Subretinal Implant - Clinical Results]. / Das subretinale Implantat ­ klinische Ergebnisse.

Since the end of the last century, subretinal electronic chips have been used to restore vision in patients blinded by degenerative retinal diseases such as retinitis pigmentosa. Various procedures have been suggested by different international scientific groups. The promising were the retinal-based concepts, for which there are now human data. The two distinct retina-based concepts not only differ in the site of stimulation (epi- or subretinal), but in their physiological concept. Whereas in camera-based systems (epiretinal, transchoroidal), eye movements cannot be used to detect objects, this is possible with subretinal access. It is as yet unclear as to whether this is relevant to restoring some kind of useful visual perception. This and other questions can only be answered by carefully designed human studies with sufficient patient numbers. Comparison of the visual results of the different groups is neither simple nor trivial. The implantations in each project need well trained and skilled retinal surgeons.

[Anti VEGF Therapy Under Real-Life Conditions: Adherance Determines Long Term Outcome in Neovascular AMD]. / Real-Life-Daten zur Anti-VEGF-Therapie: Therapieadhärenz bestimmt den Visuserhalt bei neovaskulärer AMD.

BACKGROUND: Data from real-life studies on neovascular AMD (nvAMD) generally fall significantly behind respective data from interventional prospective trials. This can be attributed at least partially to differences in patient cohorts concerning both stages of AMD (including consecutive scarring or atrophy), as well as adherence to therapy. We have been interested in the question which of the two factors most affects outcome in a real-life setting. PATIENTS AND METHODS: Retrospective study of 1500 cases of nvAMD over a time period of up to 5 years. Inclusion of all cases treated for nvAMD which received at least 3 intravitreal injections, no exclusion of cases. Treatment was according to pro re nata (PRN) scheme. RESULTS: In total, results for gain in visual acuity (letter score + 1,4 and - 0,8 for year 1 and 2, respectively), and number of injections (5,2 and 3,3) are well comparable to data from other German real-life studies. The variance within the dataset, however, is relatively large. Definition of one subgroup characterized by significantly better baseline visual acuity and significantly higher number of injections demonstrates expectedly significantly better outcome. This better performance, however, is outranged by a subgroup defined only by its significantly higher adherence to therapy. In fact, only approx. 30 % of all cases fall into this category and followed the desired PRN intervals reasonably well. This group shows gain in visual acuity of + 3,3 and + 1,6 with number of injections of 7,0 and 5,8 while not being selected according to stages of AMD at baseline. CONCLUSION: In this setting adherence to treatment more than the stage of nvAMD at baseline determined long term outcome of anti-VEGF treatment. This is encouraging for every days work where unfortunately late stages of AMD are not seen rarely. This finding emphases the importance of patient counseling and information to improve adherence to treatment.

Predictors for postoperative nausea and vomiting after xenon-based anaesthesia.

BACKGROUND: In contrast to volatile anaesthetics, xenon acts by antagonism at N-methyl-d-aspartate receptors and antagonizes 5-hydroxytryptamine type 3 receptors that mediate nausea and vomiting. Therefore, it is unknown whether the same risk factors for postoperative nausea and vomiting (PONV) after volatile anaesthetics apply to xenon-based anaesthesia. METHODS: With ethics committee approval and written informed consent, 502 consecutive patients undergoing xenon-based anaesthesia were included in a multicentre prospective observational study. Antiemetic prophylaxis was administered at the discretion of the attending anaesthetists. Postoperative nausea and vomiting and need for antiemetic rescue medication were assessed for 24 h after anaesthesia. Multivariate logistic regression analysis was performed to quantify risk factors for PONV and need for rescue medication. RESULTS: Four hundred and eighty-eight subjects were available for the final analysis. The incidence of PONV in subjects without prophylaxis was lower than expected according to the Apfel Score (28% observed; 42% expected, P<0.001). Independent predictors for PONV were (adjusted odds ratio; 95% confidence interval) female sex (1.76; 1.08-2.89), younger patient age (0.82 per 10 yr; 0.69-0.97), and longer duration of anaesthesia (1.36 per hour; 1.17-1.59). CONCLUSIONS: The incidence of PONV was significantly lower than predicted by the Apfel Score. Female sex, younger age, and longer duration of anaesthesia are risk factors for PONV after xenon-based anaesthesia. CLINICAL TRIAL REGISTRATION: German Federal Institute for Drugs and Medical Devices number AL-PMS-01/07GER.

A retrospective analysis of low dose, intranasal injected bevacizumab (Avastin) in hereditary haemorrhagic telangiectasia.

The constantly recurring epistaxis means a great reduction of quality of life for patients with hereditary haemorrhagic telangiectasia (HHT). As yet, an ideal treatment has not been found. Vascular endothelial growth factor (VEGF) has been described as a possible new therapy. In particular, the success of submucosal doses <100 mg has not been analysed before. We injected bevacizumab (Avastin) submucosally in addition to Nd:YAG laser therapy. Doses <7.5 mg were used. To investigate the effect of these additional injections in comparison to laser therapy alone, a retrospective analysis was done. For this purpose a standardized patient questionnaire was completed, which included recording the patients' Epistaxis Severity Score (ESS) before and after the antibody treatment. Besides, patient files were analysed to collect objective data like haemoglobin levels and the number of blood transfusions needed. Data for eleven patients could be analysed. A significant improvement in the ESS resulting from additional bevacizumab therapy was observed (p < 0.01). In particular, the frequency of epistaxis (p = 0.011), duration of epistaxis (p < 0.01), severity of epistaxis (p < 0.01) and the need for acute medical treatment (p = 0.014) decreased significantly. The haemoglobin levels increased significantly (p = 0.011) and the number of blood transfusions declined. There were no side effects caused by the antibody treatment. Additional injections of a low dose of bevacizumab seem to be superior to Nd:YAG laser therapy alone. These results justify further studies.

Stimulated vasopressin synthesis by a fetal hypothalamic factor.

The hypothalamo-neurohypophyseal complex (HNC) of the fetal guinea pig shows a dramatic increase in its content of vasopressin and neurophysin between the 40th and 55th days of gestation. The values for radioimmunoassayable hormone and binding protein are at day 40, 2 milliunits and less than 0.1 microgram; and at day 55, about 100 milliunits and 10 micrograms, respectively. Isotope incorporation experiments with organ cultures of the fetal HNC taken prior to the 35th day of gestation added additional confirmation of the inability of the hypothalamic neurosecretory cells to synthesize vasopressin or neurophysin at this time. However, by the 45th day, similar organ cultures show a vigorous incorporation of labeled amino acids into both hormone and binding protein. Furthermore, the HNC of the 45-day-old fetus apparently contains a factor that stimulates specifically the biosynthesis of vasopressin and neurophysin in HNC cultures from the adult guinea pig. This factor is not detectable in either cortex or liver of the 45-day-old fetus or in the fetal HNC taken prior to or after the period of exponential rise (40th to 55th days) of hormone and binding protein.

Development of sensitivity to tetrodotoxin in beating chick embryo hearts, single cells, and aggregates.

The spontaneous activity of intact embryonic heart becomes progressively more sensitive to tetrodotoxin block with increasing age of the embryo. The activity of isolated single heart cells in culture was relatively insensitive, independent of embryo age. Aggregates formed from single cells responded to tetrodotoxin in the same manner as intact hearts; aggregated cells from older hearts were sensitive.

Mapping human brain monoamine oxidase A and B with 11C-labeled suicide inactivators and PET.

The regional distributions of monoamine oxidase (MAO) types A and B have been identified in human brain in vivo with intravenously injected 11C-labeled suicide enzyme inactivators, clorgyline and L-deprenyl, and positron emission tomography. The rapid brain uptake and retention of radioactivity for both 11C tracers indicated irreversible trapping. The anatomical distribution of 11C paralleled the distribution of MAO A and MAO B in human brain in autopsy material. The corpus striatum, thalamus, and brainstem contained high MAO activity. The magnitudes of uptake of both [11C]clorgyline and L-[11C]deprenyl were markedly reduced in one subject treated with the antidepressant MAO inhibitor phenelzine. A comparison of the brain uptake and retention of the 11C-labeled inactive (D-) and active (L-) enantiomers of deprenyl showed rapid clearance of the inactive enantiomer and retention of the active enantiomer within MAO B-rich brain structures, in agreement with the known stereoselectivity of MAO B for L-deprenyl. Prior treatment with unlabeled L-deprenyl prevented retention of L-[11C]deprenyl. Thus, suicide enzyme inactivators labeled with positron emitters can be used to quantitate the distribution and kinetic characteristics of MAO in human brain structures.

Long-term evaluation of anatomic and functional results after complicated retinal detachment treated with pars plana vitrectomy and heavy silicone oil tamponade.

BACKGROUND: Heavier than water tamponades offer the possibility to support the inferior part of the fundus after retinal detachment. The aim of this study was to evaluate the anatomic and functional outcome of complicated retinal detachment treated with vitreous surgery and heavy silicone oil (HSO) tamponade. Surgery was performed in eyes with rhegmatogenous retinal detachment (RD) predominantly in the lower hemisphere or with penetrating injury (either as primary intervention or after development of proliferative vitreoretinopathy [PVR]). MATERIALS AND METHODS: Sixty-one eyes of 61 patients with RD - mostly complicated by PVR - and a minimum follow-up of 12 months were included in this study. Vitreoretinal surgery with HSO (Oxane HD) tamponade was performed in all patients. In 52 patients, heavy silicone oil was used in the management of complicated RD. 9 patients had surgery for complicated RD after penetrating eye injury.The mean follow-up period was 30.3 +/- 10.2 months. RESULTS: The overall final anatomic success rate was 79 %. In 39 % of the cases the retina remained attached during the entire follow-up period. CONCLUSIONS: The anatomic success rate after surgery with HSO (Oxane HD) was relatively low; however, only complex cases bearing a higher risk of retinal re-detachment received HSO in this study. Oxane HD does not appear to have major advantages compared to conventional silicone oil or other new-generation heavy silicone oils in these cases.

[Cost calculations for treating penetrating eye injuries within the DRG C01Z at a university eye hospital]. / Kostenkalkulation für die Behandlung von offenen Augenverletzungen in der DRG C01Z an einer Universitäts-Augenklinik.

BACKGROUND: Since 2004, inpatient health care for penetrating eye injuries in Germany had been paid according to the calculated DRG C01Z. Because the extent of treatment mainly derives from the extent of eye damage, this DRG economically summarises very heterogeneous cases. It was the aim to check the cost recovery for the surgical treatment of penetrating eye injuries at a university eye hospital. MATERIAL AND METHODS: Performance data for the DRG C01Z were collected for the years 2005 and 2006 using the E1 sheets according to section sign21 KHEntG. Costs for single operations were calculated from fixed and variable costs for the operating theatre and the ward, including costs for personnel and supplies. RESULTS: In the 2-year period, out of 4,721 inpatient procedures, 180 perforating eye injuries were surgically treated. In 80 cases, a pure corneal/scleral suture (plus cataract surgery, n=10; mean operating time 67.81 min) was performed. In the other 100 cases, a pars plana vitrectomy (ppV) with adjuvant measures (mean operating time 124.69 min) was needed. Each operation had fixed surgical costs of EUR 130.60; variable costs, including personnel and supplies, varied between EUR 570 for corneal/scleral suture (+/-EUR 250 for combined cataract surgery (n=10) and EUR 1230 (mean) for a ppV. Cost-effective additional adjuncts such as cerclage, perfluorocarbon, gas, silicone oil, or cataract surgery led to extra costs of between EUR 51 and EUR 250 per adjunct (mean EUR 182). At least two of these adjuncts were used in 50% of ppVs, and at least one was used in 90% of ppVs. Hospitalisation costs were about EUR 2184 (EUR 273 per day), with a mean stay of 8 days. The overall costs of an operation for penetrating eye injuries differed significantly in terms of the procedure (corneal/scleral suture: EUR 2662, mean length of stay 7.06 days; ppV: EUR 3712, mean length of stay 8.62 days). Additional costs for multiple surgeries, as occurred in 11.1% of all cases, were not compensated by the DRG system. CONCLUSION: In consideration of a relative DRG weight of 1,177 and a base rate of EUR 2723.79 in Bavaria for 2005 and 2006, perforating eye injuries were compensated within the C01Z DRG at EUR 3205,96. Thus, for ppVs no costs are recovered, whereas "pure suture" procedures are overweighted. Due to this inhomogeneity, a split in the C01Z DRG is necessary.

Activating transcription factor 3 induction in sympathetic neurons after axotomy: response to decreased neurotrophin availability.

Activating transcription factor 3 (ATF3) is induced in a high proportion of axotomized sensory and motor neurons after sciatic nerve transection. In the present study, we looked at the expression of this factor in the superior cervical ganglion (SCG) after axotomy and after other manipulations that induce certain aspects of the cell body response to axotomy. Sympathetic ganglia from intact rats and mice exhibit only a very occasional neuronal nucleus with activating transcription factor 3-like immunoreactivity (ATF3-IR); however, as early as 6 h and as late as 3 weeks postaxotomy, many of the neurons showed intense ATF3-IR. A second population of cells had smaller and generally less intensely stained nuclei, and at least some of these cells were satellite cells. Lesions distal to the SCG induced by administration of 6-hydroxydopamine or unilateral removal of the salivary glands produced increases in ATF3-IR similar to those seen after proximal axotomy, indicating that this response is not strictly dependent on the distance of the lesion from the cell body. Two proposed signals for triggering ATF3 expression were examined: reduction in nerve growth factor (NGF) availability and induction of the cytokine leukemia inhibitory factor (LIF). While administration of an antiserum raised against NGF to intact animals induced ATF3-IR, induction of ATF3-IR after axotomy was not reduced in LIF null mutant mice. Since axotomy, 6-hydroxydopamine, and sialectomy are known to decrease the concentration of NGF in the SCG, our data suggest that these decreases in NGF lead to increases in ATF3-IR. Furthermore, since the number of neurons in the SCG expressing ATF3-IR was greater after axotomy than after antiserum against NGF treatment, this raises the possibility that decreased NGF is not the only process regulating ATF3 expression after axotomy.

Evaluation of the Safety of Drugs and Biological Products Used During Lactation: Workshop Summary.

This report serves as a summary of a 2-day public workshop sponsored by the US Food and Drug Administration (FDA) to discuss the safety of drugs and biological products used during lactation. The aim of the workshop was to provide a forum to discuss the collection of data to inform the potential risks to breastfed infants with maternal use of medications during lactation. Discussions included the review of current approaches to collect data on medications used during lactation, and the considerations for future approaches to design and guide clinical lactation studies. This workshop is part of continuing efforts to raise the awareness of the public for women who choose to breastfeed their infants.

Tetrodotoxin desensitization in aggregates of embryonic chick heart cells.

Spontaneous beating of heart-cell aggregates from 4-day chick embryos was initially blocked by 10(-5) g/ml tetrodotoxin (TTX). With continued exposure to the drug, the fraction of blocked aggregates decreased from about 80% at 15 min to about 25% at 2-3 h, at which time, beating aggregates had become desensitized to the toxin, showing no response to a fresh dose. Aggregates from 5-day hearts were more sensitive to TTX, but fewer became desensitized in its presence. Desensitization to TTX was not seen in 6- and 7-day aggregates. Inhibition of protein synthesis by cycloheximide did not affect beating or initial sensitivity to TTX of 4-day aggregates, but desensitization failed to occur. Before TTX, the mean value of maximal upstroke velocity (V(max)) of the action potentials in 4-day aggregates was 33 V/s. After desensitization V(max) was 12 V/s. Activity of desensitized aggregates in the presence of TTX was augmented by elevated calcium levels, and suppressed by presumed inhibitors of slow inward current (manganese, D600). Desensitization was reversible; upon removal of TTX 10(-5) g/ml, aggregates regained their responsiveness to a fresh dose of the drug with a 2-3 h time-course similar to that of desensitization. This was prevented by continued exposure to TTX at concentrations as low as 10(-8) g/ml. These data suggest that (a) desensitization involves a change in the mode of action-potential generating from one involving Na-specific, TTX-sensitive channels to one utilizing slower Mn-sensitive channels; (b) the process of desensitization occurs over a period of 2-3 h and is dependent upon the products of protein synthesis; and (c) desensitization is reversible after removal of TTX over a 2-3 h time-course similar to its onset.

Macular function and morphology after peeling of idiopathic epiretinal membrane with and without the assistance of indocyanine green.

AIM: To investigate macular function and morphology after surgical removal of idiopathic epiretinal membrane (IEM) with and without assistance of indocyanine green (ICG). METHODS: A retrospective study as a consecutive case series, of 39 patients with IEM. 39 patients, 23 female, 16 male, mean age 67 years, underwent standard three port pars plana vitrectomy with removal of epiretinal membrane. Two groups of patients were consecutively operated: in 20 patients ICG 0.1% in glucose 5% was used to stain the epiretinal membrane. 19 patients underwent the identical procedure but without use of ICG. Postoperative follow up was 1-92 months (mean 15.5 months). Functional outcome was assessed with subjective improvement, best corrected visual acuity (BCVA), Amsler grid test, 10 degrees and 30 degrees automated perimetry (Heidelberg visual field analyser) (HFA), and Goldmann kinetic perimetry. Macular morphology was assessed with stereoscopic biomicroscopy and optical coherence tomography (OCT). The main outcome measures were macular function as determined by BCVA, presence of visual field defects, and metamorphopsia as determined by Amsler grid test, macular morphology as determined by slit lamp biomicroscopy, and OCT. RESULTS: BCVA improved in 28 patients, remained unchanged in eight patients, and decreased in three patients. Improvement of BCVA was statistically significant in both groups (p = 0.003). Mean BCVA in patients operated with ICG improved from 0.33 preoperatively to 0.53 postoperatively. Mean BCVA in patients operated without ICG improved from 0.32 preoperatively to 0.54 postoperatively. Reduction of macular oedema as measured by OCT was statistically significant in both groups (p<0.01). There was no statistically significant difference in postoperative BCVA, macular oedema as measured by OCT, postoperative Amsler grid test, and subjective improvement between the two groups. The incidence of residual or recurrent epiretinal membrane was greater in the group operated without ICG (p = 0.014). Visual field defects were detected in one patient operated with ICG and in three patients operated without ICG. CONCLUSIONS: Removal of epiretinal tissue with or without assistance of ICG improved visual function and reduced macular oedema in most patients. Adverse effects clearly attributable to the use of ICG were not observed but further investigation is warranted.

Implantation of stimulation electrodes in the subretinal space to demonstrate cortical responses in Yucatan minipig in the course of visual prosthesis development.

PURPOSE: During the course of the development of visual prostheses, subretinal stimulation films were implanted in micropigs in order to prove the feasibility of subretinal electrical stimulation with subsequent cortical response. One aim was to demonstrate that epidural recording of visual evoked potentials is possible in the micropig. METHODS: Film-bound stimulation electrode arrays were placed in the subretinal space of micropigs. This enabled the retina to be stimulated subretinally. Since conventional visual evoked potential (VEP) measuring is virtually impossible in the pig from the neurosurgical point of view, epidural recording electrode arrays were positioned over the visual cortex as permanent electrodes. RESULTS: The feasibility of temporary implantation of film-bound stimulation electrode arrays was successfully demonstrated in the micropig model. On stimulation with monopolar voltage pulses (1000 to 3000 mV), reproducible epidural VEP measurements (5 to 10 micronV) were detected. CONCLUSIONS: The feasibility of subretinal stimulation of the retina was demonstrated in a retinal model that is similar to the human retina. This animal model therefore offers a suitable means of studying the tolerability of stimulation situations in the course of visual prosthesis development.

Electrophysiological study of Syrian hamster hereditary cardiomyopathy.

This study was performed to determine if the intracellular electrical activity of adult cardiac papillary muscle from a strain of Syrian hamster (B10 14.6) with a genetically determined cardiomyopathy was different from that of a control strain (B10 RB). Muscles driven at rates from 1 Hz through the physiological range. Resting potentials of muscle from the two strains were not significantly different, except in increased [C2+]0, where the control was slightly hyperpolarised. Action potential overshoot was significantly greater in the myopathic at all frequencies, while the upstroke velocity was not significantly different, except at 8 Hz where the myopathic value was depressed. Action potential durations at 20, 50 and 95% repolarisation were significantly greater in the myopathic, at all rates and with increased [C2+]0. Response of the muscles to verapamil and D600 were complex, with a decrease seen in duration at 20% repolarisation and an increase in 50% duration at 1 Hz rate. No strain-related difference in sensitivity to the drugs was seen. The results supporty the hypothesis that a sarcolemmal defect is intimately related to the genesis of the cardiomyopathy.

The hypothalamo-neurohypophysial complex in organ culture: effects of metabolic inhibitors, biologic and pharmacologic agents.

Organ cultures of the guinea pig hypothalamo-neurohypophysial complex synthesize the octapeptide hormone, vasopressin, a specific product of the neurosecretory cells of the supraoptic nucleus. Inhibitors of both protein and RNA synthesis (cycloheximide and bromotubercidin respectively) were found to block vasopressin biosynthesis. In the presence of bromotubercidin, the apparent half-time of decline in the rate of hormone biosynthesis was about 28 h. Colchicine inhibited the distal transport of vasopressin into the posterior pituitary. Ultrastructural studies on colchicine-treated cultures indicated the neuronal stalks were intact and that neurotubules were still present. The narcotic drug, levorphanol at 10-7 M and 10-9 M was found to inhibit RNA synthesis by 20 percent. At these concentrations it had no demonstrable effect on vasopressin synthesis. Cultures established from animals that had been rendered tolerant to narcotics also had no observable alterations in vasopressin biosynthesis, although the initial pituitary vasopressin content of these cultures was reduced by about 35 percent. Various pharmacologic and biologic compounds were tested for their effects on vasopressin biosynthesis in organ cultures. Dibutyryl cyclic AMP, estradiol-17beta, nicotine, nerve growth factor (NGF), and pineal extract all had no effects under the present experimental regimen. Medium conditioned by the presence of fetal hypothalami of 40-55 days gestation produced a 2-4 fold increase in vasopressin biosynthesis in cultures established from adult animals. Medium conditioned by fetal cerebral cortex, liver, or hypothalamic tissue from fetuses of less than 33 days gestation did not have this stimulatory effect.

The hypothalamo-neurohypophysial complex in organ culture: morphologic and biochemical characteristics.

Organ cultures of the guinea pig hypothalamo-neurohypophysial complex could be maintained for periods as long as 3 weeks. Morphological studies using conventional light microscopy as well as electron microscopy indicate that neurosecretory cells remain viable during this time. Biochemical studies show that the capability of the cultures to synthesize a normal spectrum of cellular RNA species is impaired during the initial day in culture, but that this capability is restored after 4-5 days. Similarly, protein synthesis proceeds at low levels during initial days of culture, but increases after 5 days. These phenomena appear to be independent of changes in the specific radioactivity of precursor pools and were also observed when outgrowth of non-neuronal cells is inhibited with fluorodeoxyuridine. The content of vasopressin, a product of a specific class of neurosecretory neurons, was found to decrease in the posterior pituitary during 7 - 10 days in culture by 50-70 percent; the levels then plateaued and were maintained for up to 3 weeks. The hypothalamic content of the hormone was relatively constant throughout the culture period. Of most importance was the demonstration that the organ cultures were capable of vasopressin biosynthesis. This capability paralleled the biosynthetic activity of RNA and gross protein metabolism in that there was an initial refractory period of several days duration.

Biosynthesis of neurophysin proteins in the dog and their isolation.

Neurophysin (Np) is generally found in close association with vasopressin and oxytocin in the hypothalamo-neurohypophyseal complex. Dog neurophysin I and II have been isolated from fresh and frozen posterior pituitaries. The proteins were characterized on the basis of disc electrophoresis, immunological properties, amino acid composition and partial sequence determination. The amino terminal sequence of dog Np I is Ala-Ala-Leu-Asp-Leu-Asp-Val-Arg-Gln-Cys-Leu-Pro-Cys-Gly-Pro-Gly-Gly-Gln-Gly-while that of dog Np-II is Ala-Met-Ser-Asp-Leu-Glu-Leu. The dog Np I appears to be metabolically less stable than Np II. Isotope experiments with [35S]cystine or 3H-labeled amino acids using a design of "in vitro pulse and in vitro chase" as well as "in vivo pulse and in vivo chase," added further confirmation of the capability of the hypothalamic neurosecretory cells to synthesize concomitantly precursors of Np and vasopressin. The radioactively labeled precursors were converted to Np-like protein and vasopressin, both of which were isolated.

Male sexual development in the monkey. I. Cross-sectional analysis of pulsatile hypothalamic-pituitary-testicular function.

Pulsatile secretion of serum gonadotropins and testosterone was studied in 46 monkeys of varying ages from 9 days of age through adult life. Although some of the hormonal analysis was longitudinal in nature, most comparisons were cross-sectional. On the basis of pulsatile secretory patterns, hCG and GnRH stimulation, skeletal age, testicular volume, and histology, we have arbitrarily defined four developmental age groups: postnatal (less than 7 months), prepubertal or juvenile (7-27 months), pubertal (28-59 months), and adult (greater than or equal to 60 months). In accomplishing the pulsatile studies, blood was withdrawn at 15-min intervals over 24 h without anesthesia using a mobile vest and tether assembly to support an indwelling cannula. GnRH and hCG challenge tests were done on one or more occasions on all animals. Plasma samples were analyzed for concentrations of FSH, LH, testosterone, dihydrotestosterone and delta 4-androstenedione by established RIAs and an in vitro bioassay for LH. During the frequent sampling period of 24-h duration for all except postnatal animals, testosterone pulses of large amplitude (up to 8-fold) occurred in postnatal, pubertal, and adult animals. Pulsatile gonadotropin secretion was seen at all ages; however, the highest pulses (up to 15-fold) occurred in prepubertal animals even though this was an infrequent occurrence. Time series analysis techniques were applied for objective statistical characterization of cyclic patterns. Basic rhythms corresponding to 50- to 90-min frequency cycles in gonadotropin secretion were identified. Substantive differences between LH concentrations by bioassay and RIA were seen infrequently. Our findings illustrate that: 1) circulating gonadotropin and testosterone pulses change in amplitude but not necessarily frequency during pubertal development, and 2) primate models are a useful paradym for the longitudinal study of human male sexual development. We conclude that where direct human investigation may be limited, much can be learned by study of these primate surrogates.