Thyroid-adrenergic interactions: physiological and clinical implications.

The sympathoadrenal system, including the sympathetic nervous system and the adrenal medulla, interacts with thyroid hormone (TH) at various levels. Both systems are evolutionary old and regulate independent functions, playing probably independent roles in poikilothermic species. With the advent of homeothermy, TH acquired a new role, which is to stimulate thermogenic mechanisms and synergize with the sympathoadrenal system to produce heat and maintain body temperature. An important part of this new function is mediated through coordinated and, most of the time, synergistic interactions with the sympathoadrenal system. Catecholamines can in turn activate TH in a tissue-specific manner, most notably in brown adipose tissue. Such interactions are of great adaptive value in cold adaptation and in states needing high-energy output. Conversely, in states of emergency where energy demand should be reduced, such as disease and starvation, both systems are turned down. In pathological states, where one of the systems is fixed at a high or a low level, coordination is lost with disruption of the physiology and development of symptoms. Exaggerated responses to catecholamines dominate the manifestations of thyrotoxicosis, while hypothyroidism is characterized by a narrowing of adaptive responses (e.g., thermogenic, cardiovascular, and lipolytic). Finally, emerging results suggest the possibility that disrupted interactions between the two systems contribute to explain metabolic variability, for example, fuel efficiency, energy expenditure, and lipolytic responses.     

Treating the war casualty: case reports of polytrauma.

The new generation of wounded Warriors is vastly different from those seen in the past, and military occupational therapists (OTs) must adapt to the challenges to meet the needs of these young men and women. Three case reports will be presented demonstrating the adaptability and flexibility of military OTs serving the combat wounded Warrior. The first case report reviews the rehabilitation process of a Sailor who was hit by an improvised explosive device (IED) and sustained an open shrapnel wound to his left upper extremity. The second case report presents the complex rehabilitation process of a Soldier who sustained an open distal radius and carpal fractures with soft tissue loss to his left hand from a gunshot wound after his helicopter was shot down. The final case report represents a Soldier who was injured using a table saw while in Iraq and sustained lacerations to his left hand thumb, index, and ring fingers. These case reports represent some of the demands and challenges that military OTs face when treating the war casualty.     

An integral approach to the etiopathogenesis of human neurodegenerative diseases (HNDDs) and cancer. Possible therapeutic consequences within the frame of the trophic factor withdrawal syndrome (TFWS)

A novel and integral approach to the understanding of human neurodegenerative diseases (HNDDs) and cancer based upon the disruption of the intracellular dynamics of the hydrogen ion (H⁺) and its physiopathology, is advanced. From an etiopathological perspective, the activity and/or deficiency of different growth factors (GFs) in these pathologies are studied, and their relationships to intracellular acid-base homeostasis reviewed. Growth and trophic factor withdrawal in HNDDs indicate the need to further investigate the potential utilization of certain GFs in the treatment of Alzheimer disease and other neurodegenerative diseases. Platelet abnormalities and the therapeutic potential of platelet-derived growth factors in these pathologies, either through platelet transfusions or other clinical methods, are considered. Finally, the etiopathogenic mechanisms of apoptosis and antiapoptosis in HNDDs and cancer are viewed as opposite biochemical and biological disorders of cellular acid-base balance and their secondary effects on intracellular signaling pathways and aberrant cell metabolism are considered in the light of the both the seminal and most recent data available. The “trophic factor withdrawal syndrome” is described for the first time in English-speaking medical literature, as well as a Darwinian-like interpretation of cellular behavior related to specific and nonspecific aspects of cell biology.     

Effects of insulin and glucose on subcellular fractions from rat adipose tissue

Summary Subcellular fractions of rat adipose tissue segments incubatedin vitro were obtained by differential centrifugation. In the presence of glucose, insulin produced the following effects: (a) increased incorporation of³²P-orthophosphate and¹⁴C-glycine into the mitochondrial and microsomal fractions; (b) increased incorporation of³²P-orthophosphate into nuclear RNA. In the absence of insulin, lack of glucose increased the incorporation of¹⁴C-orotic acid into both total RNA and nuclear RNA.     

Echocardiographic diagnosis of vegetative aortic bacterial endocarditis

The echocardiograms of three patients with vegetative aortic valve endocarditis revealed characteristic shaggy or fuzzy echoes from the region of the aortic valve. At surgery or at necropsy vegetations were found that explained the distinct abnormal echoes recorded. Such echoes recorded from the region of the aortic valve in patients with evidence of acute aortic insufficiency should suggest endocarditis with vegetations. Differentiation of these echoes from echoes produced by normal phenomena, other disease states or artifacts is discussed.     

Pericardial tamponade,a new complication of amyloid heart disease

With advancing age of the population and with echocardiographic means of diagnosis, amyloid disease of the heart is of increasing clinical interest. Advanced age, restrictive myocardiopathy, arrhythmias, and conduction disorders are familiar features of this disease. A 92 year old man with past history of hemiblock followed by complete heart block and transvenous pacemaker was admitted to the hospital because of increasing fatigue and the abrupt development of dyspnea. Examination revealed paradoxic pulse, markedly elevated central venous pressure, and echocardiographically demonstrated large pericardial effusion. Shortly after admission signs of tamponade developed; 1,000 ml of pericardial fluid was removed with prompt relief of dyspnea and disappearance of paradoxic pulse and return of central venous pressure to normal. However, dyspnea soon recurred and subsequent hemodynamic measurements indicated increased right ventricular and left ventricular filling pressures. Echocardiography revealed no recurrent effusion or ventricular hypokinesis. Left ventricular ejection fraction by radionuclide ventricutogram was 64 percent. Echocardiography revealed ventricular wall thickening, normal chamber size, and glittering, sparkling myocardial echoes. On postmortem examination, there was extensive myocardial amyloidosis. There was no evidence of constrictive pericarditis or recurrent effusion. The unique aspect of this case was the combined presence of restrictive myocardiopathy and pericardial tamponade. To our knowledge, no previous case of tamponade due to amyloid heart disease has been reported.     

Cancer mortality trends in Uruguay 1953–1991

Cancer mortality trends from 1953 to 1991 were assessed by means of data supplied by the Department of Vital Statistics of the Ministry of Public Health. The population at risk was obtained from the Bureau of Statistics and Censuses. Age specific and age-adjusted mortality rates were calculated, using the world standard population, for a number of sites or groups of sites. In order to obtain relative risks of death for each period, Poisson regression models were fitted to the data using the GLIM program. The main model included age and period as explanatory variables. Among males, the principal increase was observed for lung cancer, followed by prostatic cancer. The rates were mainly stable in colon cancer and leukaemias, whereas gastric cancer showed a marked decline. Also, a recent decline was seen for oesophageal cancer. In females a steady decline in mortality was observed for all sites combined. Major decreases were seen for oesophageal, gastric, cervical and total uterine cancers. The only cancers showing significant increases were breast cancer, and lung cancer for the most recent period. Providing that there were no changes in death registration or in survival rates, changes in prevalence of risk factors might be responsible for the observed trends.     

Simultaneous induction of multiple mutations by N-methyl-N′-nitro-N-nitrosoguanidine in the yeast Saccharomyces cerevisiae

Summary Contrary to what happens in bacteria, mutations induced by nitrosoguanidine in yeast are not accompanied by an excess of mutations in nearby genes. We have investigated nitrosoguanidine mutagenesis in three regions of the yeast genome: the contiguous DNA segments HIS4A, HIS4B and HIS4C, located on chromosome III; ADE1 and CDC15 separated by about 3 map units on chromosome I; and CAN1, some 50 map units away from the centromere on chromosome V. Revertants at HIS4C never suffered mutations at HIS4A or HIS4B. Reversion at CDC15 did not affect the frequency of mutation at ADE1. No tsm mutations, leading to thermonsensitivity, were found in the immediate vicinity of the locus CAN1 after selecting for canavanine resistant mutants. However, as expected from nitrosoguanidine mutagenesis of replication points and the fixed pattern of chromosome replication, the induced tsm mutations seem not to map randomly over the yeast genome; in fact, two out of the three groups of such tsm mutations studied are located in the same chromosome arm as CAN1, indicating that these two regions are replicated at the same time as CAN1. Replication synchrony is less than perfect, since the tsm mutations of each group affect many different genes.     

Pocket computer program for fitting the Hill equation

This paper presents a program written in the BASIC language for the Radio Shack TRS-80 PC-1 or the Sharp PC 1211 pocket computers for fitting the Hill equation to experimental data. The program is based on a procedure involving a combination of an optimization technique and non-linear regression. The program determines precisely all three parameters of the Hill equation and in addition, it performs a simulation of the kinetic experiment using the parameter values previously estimated, calculating the sum of squares of residuals.