Distribution of luteinizing hormone releasing hormone in the canine hypothalamus: effect of castration and exogenous gonadal steroids

The effect of exogenous gonadal steroids or orchidectomy on the distribution and concentration of luteinizing hormone-releasing hormone (LHRH) in the hypothalamus of the dog was studied. Various hypothalamic area of the canine brain were extracted with 90% methanol and processed, and LHRH was assayed, using a specific radioimmunoassay. The highest concentration of immunoreactive LHRH was found in the infundibular, premammillary, preoptic, and suprachiasmatic areas in intact dogs. Measurable amounts of LHRH were found in the mammillary and lateral hypothalamic regions. The hypothalamus in the male dog had significantly (P < 0.05) higher LHRH concentrations 3 mm lateral to the midsagittal line (the lateral hypothalamic area) as compared with the area in the anestrous female dog. Daily estrogen treatment of female dogs with 0.2 mg/day or 1 mg/day, IM, or with testosterone propionate (1 mg/day, IM) for 3 weeks increased LHRH concentration 2.5- to 5-fold in the mammillary, premammillary, and infundibular areas and almost 40-fold in the preoptic, rostral commissural area and in the lateral and dorsal hypothalamic regions. Orchidectomy caused an increase in LHRH concentration in the preoptic and suprachiasmatic area with a concurrent decrease in LHRH in the infundibular area. Therefore, in the dog, LHRH is possibly synthesized or transported (or both) from different regions of the hypothalamus to the median eminence, and the gonadal steroid feedback mechanism is complex, involving multiple sites of action in the hypothalamus and the components of the limbic system.

Wavelength dispersion of optical waveguides

Coefficients that characterize the contribution to the total waveguide dispersion from guide geometry and from material dispersion are introduced. These are cast in terms of the normalized parameters of normalized frequency, asymmetry measure, and effective guide index. This allows plotting of universal curves for the dispersion coefficients for step thin film and exponentially graded slab waveguides that are applicable to all such structures.

Effects of intratesticular aflatoxin B1 on rat testes and blood estrogens

An investigation of the effects of aflatoxin B1 on rat testes and plasma estrogens is reported. A normal saline-suspended aflatoxin B1 was injected into right testes of mature Sprague-Dawley rats at doses of 0, 5, 10, 25 or 50 micrograms. Effects were evaluated by histopathological alterations of the testes and by levels of plasma estrogens estimated by a modified Dextron-Charcoal radioimmune assay. Significant gross lesions were present in testes injected with the 50 microgram dose. There was a 50% reduction in size and weight as compared to the left testis. Histological changes were dose-dependent, with minimal or no changes at 5 micrograms and maximal effects at 50 micrograms. The lesions varied from mild testicular degeneration to complete disappearance of cellular components. Interstitial cell proliferation, occasional calcification of seminiferous tubules, and absence of spermatogenesis and spermatozoa were extreme toxic effects. Estrogen concentrations in injected rats were reduced compared to those of control and normal rats. This study suggested that following intratesticular aflatoxin B1 exerts a direct toxic effect on testes with a reduction in plasma estrogen levels.

Isolation and partial characterization of prolactin from equine pituitary gland (hypophysis)

Highly purified equine prolactin was prepared from equine pituitary glands (hypophysis) by serial extractions with water at pH 5.5, 0.1 M (NH4)2SO4 at pH 4.0, and 0.25 M (NH4)2SO4 at pH 5.5 to remove other hormones, and then finally with 70% ethanol at pH 9.3 to 10.0 to extract prolactin. Preliminary purification of the extract involved salting out other substances with 0.1% NaCl at pH 9.0. Prolactin was precipitated out by adding three times the volume of 95% ethanol at 4 C. This prolactin preparation had a biological potency of 24 IU/mg. Further purification by isoelectric focusing on a pH gradient of 5 to 7 gave three prolactin components with the following characteristics: isoelectric point 5.8, 5.7, and 5.25; biological potencies (IU/mg) 35.6, 19.6, and 11.3. The major component had a molecular weight of 25,000, an isoelectric point of 5.8, and a biological potency of 35.6 IU/mg. Antiserum produced against this component did not cross-react with equine follicular stimulating hormone, luteinizing hormone, and growth hormone, but did cross-react with ovine and bovine prolactin. Human and murine prolactin had little cross-reactivity with the equine prolactin antiserum.

Cycloheximide inhibition of hormonal induction of alpha 2u-globulin mRNA

The induction of hepatic alpha 2u-globulin synthesis by glucocorticoids in isolated hepatocytes occurs via an increase in the level of its mRNA as measured by cell-free translation and by hydbridization to an alpha 2u-globulin cDNA probe. To explore whether induction of this mRNA is a direct or an indirect consequence of the interaction of the dexamethasone-receptor complex with the alpha 2u-globulin genome, the requirement for ongoing protein synthesis was examined. Concentrations of cycloheximide too low to prevent precursor incorporation into total poly(A)-containing RNA do prevent the hormonal induction of alpha 2u-globulin mRNA. Furthermore, incorporation of 3H-labeled amino acids into total protein was decreased by only 40-50%, and the appearance of the dexamethasone-induced glycosylated forms of alpha 2u-globulin was completely prevented in these cycloheximide-treated hepatocytes. The results suggest that the synthesis of a protein mediator(s) may be required for the induction of alpha 2u-globulin mRNA by glucocorticoids and that the steroid-receptor complex may not interact directly with the alpha 2u-globulin genome.

The natural history of rheumatic fever and rheumatic heart disease in the Orient

Studies published in the past 10 years suggest that group A streptococcal infections are frequent in the Orient and lead to a high incidence of rheumatic fever (RF) and rheumatic heart disease (RHD). In the present study, streptococcal infections were found to be more prevalent in Japan and Taiwan, whereas RF and RHD were more common and severe in the Philippines, Thailand, and Indonesia, particularly among the socioeconomically less privileged populations. The pattern of childhood RF varied: Carditis was the most common manifestation, occurring in 57% to 94% of the patients; polyarthritis was generally atypical and less common in the tropics; chorea minor and erythema marginatum were much more common in Japan, less common in Taiwan and rare in the tropics. RF recurrences were quite common and led to the development of new carditis, and deterioration or persistence of the pre-existing heart disease. The 5 year mortality rates differed greatly, ranging from zero to 42%. There was disappearance of the heart murmur in 16.5% to 37.5% of patients. Such apparent recovery was related to adherence to chemoprophylaxis. The major risk factors adversely affecting survival were the severity of carditis, inadequacy of medical service, non-compliance to chemoprophylaxis, RF recurrence, poor socioeconomic status, and high prevalence of group A streptococci. It is concluded that there is no uniform "Oriental-type" of natural history of RF and RHD. The natural history varies greatly among countries as is true in other parts of the world.

Fabrication of optical waveguide taper couplers utilizing SiO(2)

The fabrication of optical waveguide couplers involving tapered layers of SiO(2) is discussed. Details of the photolithographic fabrication processing sequence are presented. This process utilizes carefully controlled etchant undercutting and has been found to be quite reproducible. It has allowed fabrication of tapers having changes in Sio(2) thickness of 1.0,microm over lengths of 55-75 microm. Results are presented which demonstrate taper transverse uniformity for distances of over 600,microm. The smoothness and gradual nature of the tapers are apparent in scanning electron microscope pictures of a taper cross section.

Hormonal induction of alpha2u-globulin synthesis in isolated rat hepatocytes

Hepatocytes freshly prepared with collagenase synthesize alpha 2u-globulin and other hepatic proteins in vitro at approximately the same rate throughout 30 h of incubation. The newly synthesized proteins are efficiently secreted into the medium throughout this period. That the secretion of proteins by hepatocytes is not due to cell leakage is shown by the fact that 30 micrometer colchicine prevents the appearance of labeled alpha2u-globulin and other proteins in the medium. Hepatocytes isolated from animals in different endocrine states synthesize alpha2u-globulin in vitro at rates consistent with the hormonal effects upon its in vivo biosynthesis. In vitro addition of androgens to hepatocytes isolated from castrated male rats evokes an elevation of general protein synthesis in these hepatocytes. Glucocorticoids, added in vitro, specifically induce and elevated rate of alpha2u-globulin synthesis.

Effect of norepinephrine synthesis inhibitors and a dopamine agonist on hypothalamic LH-RH serum gonadotrophin and prolactin levels in gonadal steroid treated rats

The relationship between the medial basal hypothalamus (MBH) LH-RH activity and LH release was studied following progesterone (P) treatment of oestrogen-primed ovariectomized rats (day 0). Following P administration at 10.00 h (day 2) serum LH levels increased rapidly after 13.00 h to peak levels attained at 15.00 h and maintained until 18.00 h. Coincident with the onset of augmented release and peak serum LH concentrations at 15.00 h there was a significant enhancement in the MBH LH-RH activity. Thereafter, the MBH LH-RH stores promptly fell and remained at morning low levels through the rest of the LH surge period. P treatment also stimulated release of FSH and prolactin in the afternoon. Administration of norepinephrine (NE) synthesis inhibitors, diethyldithiocarbamate (DDC) and U-14,624 before P blocked the afternoon increments in serum gonadotrophins and the MBH LH-RH levels; prolactin release was also suppressed in DDC treated rats. In contrast, lergotrile mesylate (dopamine agonist) treatment prior to P administration suppressed only the afternoon increase in prolactin release. These studies show that (1) P can stimulate MBH LH-RH activity in oestrogen-primed rats and these effects are transmitted to the LH-RH peptidergic neurons via NE synapses in the preoptic area and (2) a common central NE system may mediate the stimulatory feedback effects of P on gonadotrophin and prolactin release.

Optical directional couplers with variable spacing

Optical directional couplers with variable separation are introduced and analyzed. Closed form solutions to the coupled-mode equations with variable coupling coefficient are presented. A procedure for the design of the best geometry of a variety of applications utilizing variable spacing couplers is also presented.

Diffused optical waveguides with exponential profile: effects of metal-clad and dielectric overlay

Diffusion techniques have provided an alternative to thin film technology for the fabrication of LiNbO(3) and LiTaO(3) light guiding layers. The effects of metal and dielectric film overlays on the propagation of TE and TM modes in diffused LiNbO(3) optical waveguides with expontential profile are investigated. Also examined are strip loaded metal-clad optical waveguides providing 2-D confinement to the light beam.

Serum hydrocortisone (cortisol) values in normal and adrenopathic dogs as determined by radioimmunoassay

Using a specific radioimmunoassay, serum hydrocortisone values were measured in dogs. Between 9:00 AM and 10:00 AM, the base-line hydrocortisone value for 56 clinically normal dogs ranged from 6.0 to 28.5 ng/ml, with a mean value of 17.8 +/- 1.32 ng/ml (mean +/- SEM). Marked differences due to age, sex, body weight, or breed were not observed in the hydrocortisone values. In 11 dogs with definitive hyperadrenocorticism, serum hydrocortisone values were from 32 to 148 ng/ml. In 2 dogs with hyperadrenocorticism, the values were 4.5 and 3.1 ng/ml. The estimation of serum hydrocortisone values by radioimmunoassay is simple and precise, and can be utilized to aid in the diagnosis of adrenopathy in dogs.

Possible source and control of trauma-induced glucagonemia in dogs

Plasma concentrations of glucose, insulin, and glucagon were studied in 10 adult mongrel dogs given (intravenous administration) a large dose of glucose (1g/kg of body weight) both before and after partial (50%) pancreatectomy. A proportional decrease in plasma immunoreactive insulin was observed in partial pancreatectomized dogs. Peak insulin response decreased from presurgery concentrations of 71 +/- 14 muU/ml (mean +/- standard error of the mean) in the dogs before surgical operation (presurgical value) to 52 +/- 6 muU/ml 1 or 4 days after surgical operation. Partial pancreatectomized dogs also showed a reduced plasma glucose removal rate. Fasting plasma concentrations of glucagon, on the other hand, increased by about 80%, from 253 +/- 25 pg/ml to 460 +/- 43 pg/ml 24 hours after operation. Despite an increased glucagon concentration in the dogs after partial pancreatectomy, plasma concentrations of glucagon responded (decreased) to large gulcose dosage administration. Plasma glucagon concentration returned to presurgical value by the 4th postsurgical day.

Outcomes of children with rheumatic fever not diagnosed by revised (1965) Jones criteria

The Jones criteria proposed in 1944 for the diagnosis of rheumatic fever (RF) underwent a modification in 1955, and then a revision in 1965. The importance of establishing antecedent streptococcal infection was stressed, and the criteria became more difficult to meet with. Thirty-two children, whose clinical and laboratory manifestations met the modified but not the revised Jones criteria were encountered at the National Taiwan University Hospital during 1967-1971. They were labeled as probable RF, and were treated and follwed for 1 month to 6 years (average 3.7 years). The diagnosis in each case was evaluated in the light of their outcomes. The diagnosis of RF was justified in 27 cases based upon the following observation: Favorable responses to anti-rheumatic treatment (27 cases); normalization of the enlarged heart with disappearance of the murmurs (3 cases); normalization of the enlarged heart with persistence of the murmurs (5 cases); significant reduction of the enlarged heart (12 cases); typical RF recurrence (8 cases); development of pure mitral stenosis (1 case); valvular pathology verified at surgery or autopsy (4 cases). The diagnosis in the rest of 5 cases remained not confirmed or negated because that: the enlarged heart stayed unchanged (1 case); the child remained uneventful and free of cardiac involvement (2 cases); and the patient died and no postmortem study obtained (2 cases). The risk factors leading to underdiagnosis in these patients are: 1) late coming under observation; 2) no response in ASO titers; 3) limited studies for the evidence of streptococcal infection; and 4) drug induced modification of the clinical manifestations. This study implicates that patients who are very suspicious of RF on the clinical grounds, yet fail to meet the revised Jones criteria, especially those with established valvular heart disease, should be labeled as cases of probable RF, and be treated, followed, and placed on prolonged chemoprophylaxis until proved otherwise. Recurrence of RF may thus by prevented, and the regression or even natural healing of the rheumatic heart disease will become a possibility.

Serum levels of progesterone, estradiol, and hydrocortisone in ewes after abortion due to Listeria monocytogenes type 5

Estradiol, progesterone, and hydrocortisone were measured by radioimmunoassay in peripheral serum of pregnant ewes infected with Listeria monocytogenes type 5 and in normal pregnant controls. Progesterone had decreased in both groups at abortion or parturition. Estradiol and hydrocortisone of control ewes had increased at parturition. In infected ewes, the serum hydrocortisone value was high for 3 days after inoculation, but it returned to preinoculation levels for the remainder of gestation. Serum concentrations of hydrocortisone did not change, and estradiol values increased slightly at abortion by infected ewes.

Some problems in long-term prevention of streptococcal infection among children with rheumatic heart disease in Taiwan

In Taiwan, rheumatic fever (RF) and rheumatic heart disease (RHD) remain widespread and constituting a health problem. The long-term prevention of streptococcal infections among rheumatic children has also failed to prevail, and yet has seldom been emphasized. Therefore, recurrence of RF remained prevalent. For an appraisal of the difficulties in the administration of long-term medication prophylaxis, a prospective study was started in 1967. One hundred and five consecutive cases of RF and RHD were followed up for more than 1 year to 6 years with an average of 4.4 years. One hundred and two cases received monthly injections of benzathine penicillin G for 6 months to 6 years, of whom 10 were switched to daily sulfa drugs; 1 case had oral penicillin daily for 6 years; in 12 cases, sulfa drugs were given for 6 months to 5 years. Fifty-one cases (48.6 %) stayed well in the program; 22 (21.0 %) stayed but were not compliant; 32 (30.4 %) dropped out soon or after staying in for more than 1 year. Major risk factors leading to non-compliance are; 1) apparent recovery from the illness or resumption of the normal activity; 2) cram session at school; 3) lack of easy medical care system; and 4) shortage of active participation by the health workers and general practitioners. The present study confirmed that the long-term prevention of streptococcal infection was effective and contributed to the decline of RF recurrence rate from more than 30 % down to 6%. Our study implicates that this important preventive program can not be achieved just only by the hospital staff, but should be approached jointly by all doctors, health and social workers, school teachers and the parents.

Integrated optical silicon photodiode array

We consider device design, fabrication, and operation of integrated optical photodiode arrays in which p-i-n junction photodiodes are formed in silicon. A SiO(2) layer on silicon serves as the effective substrate for a KPR waveguide. Light is coupled from the waveguide at the detector region either through the evanescent field or by multiple refraction into the detector. The waveguide-photodiode structure is designed so that nearly 100% of the incident optical energy can be absorbed in the photodiode junction depletion region. A device quantum efficiency of 80% is measured compared to a theoretical value of 93%.