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%.

Relationship of structure to function in bacterial endotoxins: serologically cross-reactive components and their effect on protection of mice against some gram-negative infections

Rabbit antisera were prepared against the heptoseless Re mutants, Salmonella minnesota R595 and S. typhimurium SLI102, as well as against purified R595 glycolipid coated on autologous erythrocytes. The antisera cross-reacted with the endotoxic glycolipids extracted from Re mutants of various bacterial strains, including S. minnesota R595, S. typhimurium SLI102, Escherichia coli D3Im4, E. coli D2If2 and E. coli F515, as shown by passive haemagglutination and gel diffusion tests. The anti-Re sera also cross-reacted with the RESI preparations (a purified 'lipid A' fraction) from the endotoxic lipopolysaccharides of various heterologous smooth Gram-negative bacteria including Serratia marcescens. Psuedomonas fluorescens and E. coli 0127. However, the same antisera failed to protect mice against infection by Gram-negative bacteria such as Klebsiella pneumoniae type II, S. typhi 0901, P. aeruginosa 119 and E. coli. The results suggest that although the lipid moieties of the lipopolysaccharides in the cell wall of Gram-negative bacteria share cross-reactive immunodeterminant groups, these groups may not be accessible to antibody against them.

Relationship of structure to function in bacterial endotoxins. IX. Differences in the lipid moiety of endotoxic glycolipids

Chemical, immunochemical, chromatographic, and endotoxic properties of five chromatographically pure glycolipids were compared. The preparations were extracted by chloroform-methanol from three Escherichia coli, one Salmonella minnesota, and one S. typhimurium Re heptoseless mutant strains. The local Shwartzman skin assay, the nonspecific resistance-enhancing effect, and the Limulus assays could not distinguish among the five glycolipids, all five being active in all three assays. Significant differences could be seen when the tumor resistance-enhancing effect of the glycolipids in mice was compared with the nonspecific TA3-Ha murine mammary adenocarcinoma growing in ascites form. Even greater variation was observed in the capacity of the preparations to enhance the nonspecific resistance of mice to virulent S. typhi 0901 infections. The data show that the five glycolipids are quite dissimilar in their biological effects. Similarly, thin-layer chromatography and molecular ratio determinations showed that differences exist in the chemical structure of the glycolipids. Accordingly, we claim that not only the polysaccharide but the lipid moiety as well may vary in various gram-negative endotoxin preparations.

Studies on metabolism and effects of estrogen on pituitary prolactin and LH secretion

The effect of a subcutaneous injection of estradiol on the secretion of pituitary prolactin in the rat and the relationship between serum estradiol level and luteinizing hormone (LH) secretion in mare were reviewed. In addition, the effect of estradiol injection on LH secretion and the metabolism of [14C] estradiol in intact and bile duct fistulated pony mares were studied. Low (0.1 mug/day/rat) to moderate dose (5 mug/day/rat) of estradiol benzoate injected subcutaneously to mature or immature rats significantly increased pituitary content of prolactin and serum prolactin level five- to tenfold. On the other hand, high dose of estradiol (10 mug/day/rat or more) was less effective in stimulating prolactin secretion, and it appeared that progesterone injected concurrently with estradiol had some inhibitory action on the stimulatory effect of estradiol. Studies in pony mares showed that the physiologic level of serum estradiol during proestrus was important for the induction of the ovulatory surge of LH. Intramuscular injection of a low dose (2 or 4 mg/mare) of estradiol was stimulatory, whereas a high dose (8 mg/mare) was inhibitory for LH secretion in pony mares. Results of the estradiol metabolism studies indicated a relatively long half-life for estradiol in the mare. The majority of the [14C] estradiol metabolites appeared in the urine within 24 hr following intravenous injection. Enterohepatic circulation appeared to be important for estradiol metabolism in mare.