Successful medical treatment of aortic intramural hematoma (Stanford type B) in a patient with aberrant right subclavian artery: A case report

Intramural Hematoma (IMH) forms part of the acute aortic syndrome, aortic dissection, and penetrating aortic ulcer. It is a life-threatening aortic disease that warrants prompt diagnosis and management. Like aortic dissections, it is classified using the Stanford classification system as type A (proximal to the origin of the left subclavian artery) and type B (distal to the origin of the left subclavian artery). Patients with type A IMH is generally managed surgically, and uncomplicated type B IMH is managed medically. The right subclavian artery arises typically from the brachiocephalic trunk. Aberrant right subclavian arteries (ARSA) are rare and derive directly from the aortic arch distal to the left subclavian artery. In this case report, a 73-year-old female presented with right-sided chest pain and shortness of breath. On examination, her heart rate was 100 bpm and blood Pressure was 185/85 and her ECG showed sinus rhythm. Following a CT scan, she was found to have a type B Aortic IMH with an ARSA. She was medically managed with vigorous blood pressure control. After a period of intravenous blood pressure treatment, she was treated with oral medication. Her subsequent CT scan showed that the hematoma was stable. She was followed up with MRI scanning 1 year later, which showed complete healing of the aorta with no changes in diameter. This case illustrates the importance of strict blood pressure management and follow-up imaging in patients presenting with type B IMH. It is important to monitor these patients regularly and where blood pressure control alone is not sufficient, further intervention may be required. Even though the complete resolution may be achieved as in this case, these patients will need to be kept under surveillance with repeated scans to monitor for any changes.     

Structural-functional differences of a crab motoneuron to four stomach muscles

A motor unit in the stomach of the blue crab, Callinectes sapidus, consists of four separate muscles involved in different aspects of the trituration and filtering of food. Motor nerve terminals to two of the muscles (CPV7a and GM5) release small amounts of transmitter (low-output) while those to the other two muscles (CV2 and CV3) release between three and five-fold greater amounts (high-output). Structural features underlying the disparity in synaptic strength were analysed with thin serial-section electron microscopy. Nerve terminals were similar in their volume percent of mitochondria, clear vesicles and dense core vesicles among the four muscles. This was also the case for the number and size of synaptic contacts. However, presynaptic dense bars representing active zones were longer and occurred more frequently at high-output synapses than at low-output ones. High-output synapses were also characterized by the close spacing of adjacent dense bars. The longer and more closely spaced dense bars at high-output synapses would be factors in the generation of larger synaptic potentials in these terminals compared to their low-output counterparts. Other factors, however, need to be considered to fully account for the physiological differences in synaptic strength among the four muscles.     

Effect of starvation and insulin-induced hypoglycemia on oxidative stress scavenger system and electron transport chain complexes from rat brain, liver, and kidney

Considerable evidence suggests that oxidative stress plays an important role in tissue damage associated with hypoglycemia and other metabolic disorders. The altered brain neurotransmitters metabolism, cerebral electrolyte contents, and impaired blood-brain barrier function may contribute to CNS dysfunction in hypoglycemia. The present study elucidates the effect of starvation and insulin-induced hypoglycemia on the free radical scavanger system—reduced glutathione (GSH) content, glutathioneS-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR), γ-glutamyl transpeptidase (γ-GTP), γ-glutamyl cystein synthetase (γ-GCS), catalase and superoxide dismutase (SOD), and mitochondrial electron transport chain (ETC) complexes I–IV from three different regions of rat brain, namely cerebral hemispheres (CH), cerebellum (CB), and brainstem (BS). Peripheral organs, such as liver and kidney, were also studied. Significant changes in these enzymic activities were observed. The analysis of such alterations is important in ultimately determining the basis of neuronal dysfunction during metabolic stress conditions, such as hypoglycemia, and also defining the nature of these changes may help to develop therapeutic means to cure metabolically stressed tissues.     

Neural factors influence the degeneration of muscle fibers in the chelae of snapping shrimps

The asymmetric pincer and snapper claws in the snapping shrimp differ in external morphology and musculature. The snapper is a massive claw used for displays and defense; the pincer is small and slender, used for feeding and burrowing. The snapper has only slow muscle fibers; the pincer has both slow and fast. Removal or denervation of the snapper claw induces transformation of the contralateral pincer to a snapper type of claw at the subsequent molt. A removed claw regenerates as a pincer type, as long as the innervation of the remaining claw is intact. Fast muscle fibers, found exclusively in the pincer claw, normally degenerate completely within 10 d after the moult, which transforms the pincer to a snapper. Morphological transformation of the pincer following removal of the snapper claw can occur even if the pincer claw is denervated. Denervation of the pincer, however, delays degeneration of the fast fibers, increasing the estimated half-time for muscle degeneration, from 4.4±0.2 to 19.5±0.8. d after the transforming moult. Neural influences there-fore are involved both in the determination of the morphology of the claw and in the induction of degenerative changes during the remodeling of an existing claw.     

Age-related remodeling of lobster neuromuscular terminals.

Multiterminal innervation of a lobster limb muscle by an identified excitor motoneuron was examined during primary development and adult growth. To keep pace with the growth in the target muscle, axonal branches proliferate by sprouting from synaptic terminals; an increasingly complex branching pattern results. Neuromuscular synapses multiply in number, enlarge in size, and become perforated. Concomitantly, synapses tend to appear on the more distal axonal branches and to disappear on more proximal branches, providing for continual remodeling of multiterminal innervation. This plasticity in an identified motoneuron occurs over a long life span of several decades.     

A Correlative study of blood histamine and clinico-pathological presentation in vasomotor rhinitis

100 clinically diagnosed cases of vaso-motor rhinitis were investigated for blood histamine level, peripheral blood eosinophil count and nasal smear examination for eosinophils. The blood histamine was found to be raised in 56 cases and an increased eosinophil count in blood and nasal secretions was observed in 29 and 32 cases respectively.     

Growth-related features of lobster neuromuscular terminals

Neuromuscular terminals of the low-output type formed by the single excitor axon to the limb distal accessory flexor muscle in the lobster Homarus americanus were studied with serial section electron microscopy. This type of innervation was compared between a small and a large lobster where a two-fold difference in mean quantal content of synaptic transmission was found. Several growth-related changes in the fine structure of these low-output synaptic terminals were seen. First, there was a proliferation of multiterminal innervation consisting of an increase in the number of nerve terminals, synapses and presynaptic dense bars between the small and large lobster. Also the mean surface area of the synapses increased significantly in the large compared to the small lobster. Second, synapses possessed distinct areas of non-specialized membrane or perforations which showed a growth-related increase in their number per synapse between small and large lobsters. Such perforations also occurred in the high-output synapses but only amongst the larger synapses of the older lobster. It is proposed that these perforations subdivided synapses into smaller functional units for membrane recycling as they provide a ready source of non-synaptic axolemma for nearby active sites (dense bars). Third, the branch point between subsidiary and principal terminals as well as the ending of a terminal is composed of synaptic membrane which is presumably involved respectively in the sprouting and elongation of nerve terminals during growth. Altogether these observations signify both qualitative and quantitative changes in identified neuromuscular terminals with growth.     

Decrease in transmitter output and synaptic ultrastructure at lobster neuromuscular terminals with decentralization

The effects of decentralization on the physiology and ultrastructure of neuromuscular terminals were examined by transecting the single excitor axon to the distal accessory flexor muscle in the walking legs of lobsters (Homarus americanus). Decentralization caused a reduction in the amplitude of the excitatory junctional potential without altering the resting potential or input resistance of the muscle fiber thereby suggesting a reduction in transmitter release. Confirmation was obtained by recording of synaptic currents at focal sites which showed failure of transmission and a reduced amplitude on decentralized fibers compared to their intact counterparts on the contralateral leg. The mean quantal content of synaptic transmission decreased approximately 2-7-fold at these decentralized sites compared to their intact counterparts. The ultrastructure of these identified sites was examined with serial section electron microscopy. There are few if any qualitative changes in synaptic ultrastructure between decentralized and control terminals. However, quantitatively there were changes in synaptic ultrastructure which were progressive in nature depending on the severity of the reaction to decentralization. Thus terminals showing a moderate decline in quantal content were characterized by a reduction in the number of presynaptic dense bars and synapses. Terminals showing a severe drop in transmitter release showed in addition to the above changes, a reduction in the size of synapses and terminals. These results show a progression in the loss of the structural parameters controlling transmitter release. Finally synaptic vesicles and mitochondria did not reveal any consistent or marked change with decentralization.     

Gastric Bypass for Insulin Resistance due to Lipodystrophy

We report a 41-year-old woman with severe insulin resistance due to partial lipodystrophy, who was successfully treated with gastric bypass surgery.