Melatonin modifies the spontaneous multiunit activity recorded in several brain nuclei of freely behaving rats.

Melatonin, a pineal hormone, released photoperiodically, was administered systemically in rats, previously implanted with semimicroelectrodes into six different brain structures. The multiunit electrical activity of these structures was recorded for 10 min before and 60 min after melatonin administration in unanesthetized, freely moving rats. Different melatonin doses (100, 200, 500, and 1000 micrograms/kg) produced changes in the electrical activity of all tested structures. However, amygdala, rostral hypothalamus and mesencephalic reticular formation showed the most important changes. The main effect induced by melatonin was a dose-related decrease of the spontaneous electrical activity. The significance of these effects is discussed within the context of the behavioral and endocrinological effects of melatonin.     

A correlation between muscular strength and hydroxyproline concentration in human patellar tendon

The connective tissue of the knee is frequently injured by athletes, especially those involved in contact sports. It would be important in the prevention of injury as well as the strategy of physical fitness training to know whether the connective tissue is modified in response to athletic stress or training. The potential modification investigated was variability in the concentration of hydroxyproline, a post-translationally modified imino acid found principally in collagen protein. A correlation was sought between this variability and the leg strength parameters torque (expressed as ft-lbs), torque/body weight and work (expressed as ft-lbs). In a preliminary study of five subjects, no correlation was found between hydroxyproline concentration of the patellar tendon and any of the leg strength parameters. These results suggest that this modification of the collagen in connective tissue does not occur in response to athletic stress or training, but rather, for the small number of subjects investigated, appeared to be relatively constant across a range of leg strengths.     

Central nervous control of hepatic circulation.

This study was undertaken to assess the role of the hypothalamus and medulla oblongata in regulation of liver circulation in anesthetized dogs. Blood pressure, flow in hepatic artery and portal vein, and shifts of blood volume in the liver were recorded. Stimulation of the anterior hypothalamus produced changes in arterial pressure which were followed by passive changes in hepatic arterial blood flow; changes in hepatic artery resistance were rather small. Stimulation of the medial and posterior hypothalamus increased hepatic arterial resistance by 65-170%. Liver portal blood flow during stimulation of most of the hypothalamic sites decreased, hepatic portal pressure rose and vascular portal venous resistance increased 2.5-3 times. Three areas only (sympatho-inhibitory area, paraventricular and lateral hypothalamic nuclei) when stimulated produced dilatation of hepatic portal and splanchnic vascular beds, thus increasing portal blood flow. All cases of stimulation led to the decrease of blood volume in the liver by 10-36%. Stimulation of medullary structures (n. tractus solitarii, reticular nn.) caused similar changes in hepatic circulation, however the amplitude of reaction was 1.5-6 times smaller than upon hypothalamic stimulation. Central impulses to the hepatic vessels are transmitted by sympathetic adrenergic nerve fibers through vascular alpha-adrenoreceptors. It is concluded that the hypothalamic level of the central nervous system, unlike the bulbar one, exerts considerable, differentiated, well coordinated and to some extent specific influences on hepatic circulation.     

The National Commission on Nursing Implementation Project

On May 1, 1991, the National Commission on Nursing Implementation Project officially concluded. Its legacy is one of interdisciplinary collaboration and continuing work to redesign nursing education, practice, and research systems.     

Klebsiella pneumoniae liver abscess with septic endophthalmitis. The role of computed tomography

Klebsiella pneumoniae liver abscess associated with septic endophthalmitis is a rare observation. To our knowledge, only 10 cases have been reported in the international literature. We report a further case of complication occurring in an adult woman with hypothyroidism, and comment on the role of CT for the work-up.     

Methodological Issues Associated with an Audit of Stillbirth in a Family Medicine Practice in Israel

An audit of ‘deficient outcome’ involves the step-by-stepanalysis of every event preceding the occurrence of a preventablemedical outcome in order to determine exactly what went wrong.This paper describes methodological problems and related issuesassociated with a deficient outcome audit undertaken on fivestillbirths which occurred in a rural family medical practiceIsrael between 1985 and 1987. Problems included initial officialdisinterest towards the audit, and the high levels of suspicionand antagonism which it aroused in hospital staff approachedfor information. The problematic aspect of such audits needsmore attention. The importance of this type of audit for establishing the precisereasons for perinatal deaths, and thus for maintaining antenatalcare standards is discussed. In view of the small numbers ofsuch events likely to occur within any one family practice itis not only feasible but also desirable for more family doctorsto carry out such audits routinely, despite the difficultieswhich are involved.     

Mitogenic and protein synthetic activity of tissue repair cells: control by the postsurgical macrophage

It is well known that fibroblasts are a main source of extracellular matrix synthesis necessary for tissue repair. In addition, macrophages secrete products that are known to modulate synthesis of extracellular matrix. Accordingly, we studied the incorporation of [3H]thymidine, [3H]proline, and [35S]sulfate into macromolecules produced by fibroblasts recovered from the site of peritoneal tissue repair cultured with and without spent media from postsurgical peritoneal macrophages. Rabbits underwent resection and reanastomosis of their small intestines. Peritoneal exudative cells (PEC) were then collected on postsurgical day 5 and day 10 as well as from nonsurgical controls, separated by discontinuous Percoll gradient centrifugation, and cultured for 48 h. A second group of rabbits underwent peritoneal wall abrasion from which fibroblast tissue repair cells (TRC) were collected from the site of injury at postsurgical day 7 and maintained in culture for varying times. Incorporation of radiolabeled precursors into DNA, collagen, and sulfated proteoglycans was determined. Incorporation of [3H]thymidine and [3H]proline into untreated TRC gradually decreased with culture duration. Conversely, [35S]sulfate incorporation gradually increased during prolonged culture. Macrophage spent media increased the levels of [3H]thymidine incorporation by the TRC. [3H]Proline and [35S]sulfate incorporation into TRC were also stimulated by macrophage spent media. However, this stimulation may be due to the enhanced proliferation of TRC by macrophage spent media. In conclusion, tissue repair fibroblasts are activated for postsurgical repair at the site of injury by many factors including secretory products from postsurgical macrophages.     

Myopathies of the lower extremities

The myopathies that can manifest themselves within the lower extremity are reported here and can serve as a guideline for clinicians in the early diagnosis of these disabling conditions. The classification of these disease entities based on signs and symptoms is significant if correlated with the age of the patient at the time of onset, the evolution and course, and the type of familial inheritance. This article can also aid the practitioner in assessing and planning the course of treatment for a particular patient.