Biomedical subjects
Publications and source records attributed to N Martin.
We report a case of severe respiratory distress syndrome which required intermittent positive pressure ventilation and led to severe pulmonary interstitial emphysema (PIE) and massive air embolism.
The ability to voluntarily stabilize the head in space during lateral rhythmic oscillations of the trunk has been investigated during parabolic flights. Five healthy young subjects, who gave informed consent, were examined. The movements were performed with eyes open or eyes closed, either during phases of microgravity or phases of normal gravity. The main result to emerge from this study is that the head may be stabilized in space about the roll axis under microgravity conditions with, as well as without vision, despite the reduction of the vestibular afferent and the muscle proprioceptive inputs. Moreover, the absence of head stabilization about the yaw axis confirms that the degrees of freedom of the neck can be independently controlled, as it was previously shown. These results seem to indicate that voluntary head stabilization does not depend crucially upon static vestibular afferents. Head stabilization in space may be in fact organized on the basis of either dynamic vestibular afferents or a postural body scheme.
This study measures the changes in dimension and weight resulting from water sorption in light-cured resin-based materials using an innovative computer-controlled laser micrometer and a precision digital balance. Three materials are examined in this study: a micro-filled composite, a dual-cure luting composite and a compomer. Five discs of each test material were prepared, weighed and the size of each disc was measured across sequential diameters by a computer-controlled laser micrometer. Measurements were carried out at intervals over a 24-month period. Significant changes in the rate of percentage weight gain and the rate of percentage linear expansion occurred for up to 90 days for the composite restorative and the luting material and up to 150 days for the compomer. This study concludes that over a period of 24 months, the hygroscopic expansion of the compomer material is significantly greater than that of the conventional composites tested.
An isolated sarcoid involvement of the pineal region is reported. This case is of interest because of an unusual clinical onset, an exceptional location, and a positive response to radiotherapy after unsuccessful steroid therapy. The evolution of this case as shown by CT and magnetic resonance studies is discussed.
To assist in the distinction of melanoma from benign pigmented lesions, an imaging system was developed, comprising a frame grabber, a microcomputer, a colour video camera and flash lighting with red, green and infrared filters. Over an 18-month period, video images of 70 unselected pigmented lesions for which complete diagnostic data were available, were successfully captured using the camera. Analysis software extracted features relevant to the size, colour, shape and boundary of each lesion, and these features were correlated with clinical and histological characteristics on which standard diagnoses of skin tumours are based. For discriminant analysis based on image analysis measurements, equal probabilities were assigned to three specified diagnostic groups, namely melanoma, naevi and 'other', and four of five melanomas were correctly classified when infrared data were included. However when infrared measurements were omitted, all five melanomas were correctly classified, and the overall accuracy of classification of pigmented lesions was 71%. This system holds promise as an aid in the clinical distinction of melanoma from benign pigmented skin lesions.
A 7-year-old boy with T cell acute lymphoblastic leukemia developed disseminated hyalohyphomycosis due to Fusarium solani. The clinical features included fever, severe myalgia, documented fungemia with F. solani, an ecthyma gangrenosum-like lesion next to a peripheral venous catheter, and disseminated pustules. Severe neutropenia due to chemotherapy was the most relevant risk factor. Histopathologic study of the ecthyma gangrenosum-like lesion, as well as pustular lesions, revealed epidermal necrosis and an inflammatory infiltrate in the upper dermis, with numerous septate hyphae demonstrated by periodic acid-Schiff stain. Clinical resolution was achieved with granulocyte colony-stimulating factor and amphotericin B administration. Our case suggests that the peripheral venous access was probably the portal of entry of the fungus.
This article provides an introduction to seasonal affective disorder (SAD) and outlines various therapies, including phototherapy (light therapy), used in its treatment. SAD, colloquially termed 'winter blues', is a common condition that is thought to be caused by reduced levels of daylight in winter. During this period sufferers generally feel low and may experience clinical depression. The Department of Psychiatry at the University of Southampton has an established SAD service as part of its mood disorders clinic, which was developed from a research-based clinical investigation unit set up in the early 1990s. SAD is described as a mood disorder with a seasonal pattern and has a greater prevalence in countries with greater northern latitude. The aetiology of SAD is unclear, although the most promising theory suggests the role of the neurotransmitter serotonin. SAD is difficult to treat with conventional antidepressants although there is evidence that serotonin selective reuptake inhibitors may be useful for some patients. Phototherapy (light therapy) has been used successfully by many patients although it remains controversial and difficult to obtain on the NHS.
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PURPOSE: To describe our experience with the use of Amytal injected through a superselective catheter prior to planned embolization of cerebral arteriovenous malformations. MATERIALS AND METHODS: 109 superselective tests were performed with 30-mg injections of Amytal. All patients were evaluated by both clinical examination and EEG. RESULTS: Twenty-three of these tests were positive. There were no prolonged neurologic complications of the Amytal test. We also examined the value of EEG monitoring compared to clinical monitoring during the Amytal test. Of the 23 positive Amytal tests, only 12 showed a change on clinical exam (52%). This meant that almost half of the positive Amytal tests would have been falsely called negative (false negative rate of 10%). There were also three positive Amytal tests with changes on clinical examination without any change on EEG. CONCLUSION: The superselective Amytal test can be done safely as part of the interventional neuroradiologic procedure. Clinical and EEG monitoring of the patient are essential.
PURPOSE: To describe the incidence of neurologic dysfunction following embolization of supratentorial AVMs, and to correlate findings with results of preembolization Amytal tests. MATERIALS AND METHODS: Data from 147 embolizations of supratentorial AVMs following Amytal tests in 30 awake patients were analyzed retrospectively. RESULTS: Of five embolizations done after a positive Amytal test, two were followed by neurologic complications. Eighty-two embolizations done as single embolizations immediately after a negative Amytal test were associated with no neurologic complications. The remaining embolizations were parts of multiple series of embolizations, each beginning with an Amytal test and followed by a number of embolizations without catheter movement or repeat Amytal testing. Since any prior embolization in the series might reduce the sump effect of the AVM, embolic agent delivered later in the series could potentially reach functional brain tissue not fully tested by the Amytal test. Therefore, repeat embolizations (not immediately preceded by an Amytal test) were considered separately. In 60 repeat embolizations, six (10%) were associated with some neurologic complication. CONCLUSIONS: Repeat Amytal testing might detect the loss of sump effect as the AVM is embolized. We conclude that use of data from superselective Amytal tests adds to the safety of AVM embolizations and that repeat Amytal testing potentially could be valuable when serial embolization of a vessel is planned.
With the use of Tracker and Balt microcatheter systems, intravascular pressure measurements were obtained in an experimental animal model, establishing the reliability of mean blood pressure measurements from these microcatheter systems. In the experimental model, selective occlusion of branches of the external carotid artery with simultaneous pressure measurements showed significant and reproducible changes in intravascular pressures. Also, pharmacologic manipulation of the blood pressure with simultaneous microcatheter and 6-French catheter recordings demonstrated an accurate and linear response of the microcatheter systems to mean blood pressure as it varied from 30 to 130 mm Hg. Preliminary results in humans with vascular malformations yielded similar results. We studied two cases of brain arteriovenous malformations (AVMs), one sigmoid-transverse sinus dural AVM, and one brain arteriovenous fistula (AVF). In these four cases the pressure dropped substantially, approaching the level of the shunt. In the case of the brain AVF, pressures rose in the same vessel after embolization. In the case of the dural AVM, correlation of the venous pouch pressures and the angiographic appearance indicated that shunting was no longer present when the venous and arterial pressures equalized. This system can be of substantial benefit in the evaluation and therapy of these lesions, and may increase our understanding of the physiology of vascular malformations.
Three patients with diffuse idiopathic cranial pachymeningitis with predominant involvement of the tentorium and falx are reported. Progressively increasing headaches were the usual symptoms, along with ataxia and various cranial nerve palsies. CT in all cases and MR imaging in two cases detected isolated thickened dura mater. In one case, MR depicted dural involvement as a very large, hypointense area with fine hyperintense edges on T2-weighted images. Microscopic examination of thickened dura revealed extensive fibrotic tissue with a chronic inflammatory infiltrate containing lymphocytes, plasma cells, and scattered eosinophils; these findings closely paralleled the MR features. Only four cases with similar pathologies have been described, all before the advent of CT and MR. We discuss the different causes of thickened dura mater as well as the significance of the fact that dural thickening can be responsible for occlusion of the dural sinuses. Cranial pachymeningitis is a rarely reported disease that can resemble other disorders associated with tentorial thickening; CT and MR can help differentiate it from these other disorders.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Results from three cancer registries (Chiang Mai, Khon Kaen, and Songkhla) in different regions of Thailand and from a cancer survey in the population of Bangkok during the years 1988-1991 are presented, together with an estimate of the incidence of cancer for the country as a whole. Overall, liver cancer is the most frequent malignancy, but there are large regional differences in incidence and in histological type, with very high rates of cholangiocarcinoma in the northeast (associated with endemic opisthorchiasis) but a more even distribution of hepatocellular carcinoma. Lung cancer is second in frequency, with the highest rates in northern Thailand, where the incidence in women (Age Standardized Rate, 37.4 per 100,000) is among the highest in the world. A link with tobacco smoking is suggested by similarly raised rates, especially in women, for cancers of the larynx and pancreas. Cervical cancer is the most common malignancy in women, with relatively little regional variation in risk, while the incidence of breast cancer is low. Other cancer sites showing moderately increased rates include the lip and oral cavity, particularly in females from the north and northeast, where the chewing of betel nut remains common among older generations, nasopharyngeal cancer, carcinoma of the esophagus in the southern region, and penile cancer, especially in the north and northeast. Previous studies which have investigated the etiological factors underlying these patterns are reviewed, and the implications for future research and for national cancer control policies are discussed.
We report two unusual cases of double spinal dural arteriovenous fistulas. Both patients had signs and symptoms commonly described in this condition, but selective angiography of the spinal cord demonstrated two separate dural arteriovenous fistulas with separate venous drainage for each fistula.