Biomedical subjects

G Deutsch

Publications and source records attributed to G Deutsch.

At least 37 records · Page 2Linked to original sources

PubMed1996

Radiotherapy treatment of age-related subfoveal neovascular membranes in patients with good vision.

This prospective study investigated whether low-dose ionising radiotherapy preserved vision and caused membrane regression in patients with age-related subfoveal neovascular membranes (SFNVMs) or vascularised pigment epithelial detachments (PEDs) and relatively good initial visual acuities. Twenty-five patients with initial Snellen acuities of 6/24 or better were treated with low-dose external beam radiotherapy. Of the patients with SFNVMs, visual acuities were maintained or improved in 58% at 6 months and 53% at 1 year. Neovascular membrane size was assessed by image analysis and showed some regression in 47% and 41% at 6 and 12 months respectively. These results suggest that patients with SFNVMs and good vision may benefit from radiotherapy, faring better than previous reports of the natural history of this condition. Conversely, patients with vascularised PEDs did not appear to benefit from radiotherapy. Only 17% maintained their vision at 1 year and 33% suffered retinal pigment epithelial tears. The results from patients with SFNVMs and good initial vision, excluding those with vascularised PEDs, are encouraging however, any benefit from this treatment needs to be proven by controlled trials with long follow-up.

Aged↗

PubMed1996

Tc-99m HMPAO brain SPECT scanning in Munchausen syndrome.

Regional cerebral blood flow was studied in a patient with Munchausen syndrome using high resolution Tc-99m HMPAO SPECT. The scan demonstrated marked hyperperfusion of the right hemithalamus. The cranial CT scan was normal. The abnormal right hemithalamic blood flow is discussed in relation to the hypothesized neuropathy of this disorder.

Female↗

PubMed1995

Innovative technique for Norplant implants removal.

This study evaluates a unique and completely different approach from the original removal technique. The main objective of this technique is to facilitate removal of widely-spaced, deeply-positioned, and misplaced Norplant capsules. A local anesthetic is injected deep and perpendicular to the long axis of the Norplant rods. The hypodermic needle is left in place underneath the six silicone rods for the entire removal procedure. One or two 3-4mm vertical incisions were made between the capsules over the needle. The Norplant rods were dissected free from the fibrous tissue and the skin with a #11 blade. A curved mosquito forceps was inserted between the skin and the Norplant rod, to hook and deliver the capsule through the incision, from where it can be easily removed. This method resulted in far less time, effort, and skill from the health care provider, no damage to the capsules, and much less trauma to the clients.

Anesthetics, Local↗

PubMed1994

2D 1H spectroscopic imaging of the human brain at 4.1 T.

A two-dimensional spectroscopic imaging sequence consisting of an inversion recovery pulse, a plane selective prefocused pulse, and a semiselective water suppression pulse has been used to create 1H spectroscopic images of the human brain with nominal voxels of 0.5 cc. Due to the excellent lipid suppression provided by the inversion recovery pulse and subsequent delay, only planar volume selection is required enabling the entire brain within the slice to be imaged without contamination from extracerebral lipids in the brain voxels. The use of a semiselective refocusing pulse for water suppression permits any echo evolution time to be used, minimizing J-modulation and T2 losses, while retaining full sensitivity in the lactate resonance. Using this sequence we have visualized the lactate elevation in the peri-infarct region about a 6-week-old stroke.

Brain↗

PubMed1994

A phase I study of letrazuril in AIDS-related cryptosporidiosis.

OBJECTIVE: The intestinal parasite Cryptosporidium is a common cause of chronic diarrhoea in AIDS patients and is responsible for significant morbidity and mortality. No effective treatment is currently available for this condition. Here we aim to determine the safety, tolerance, and clinical effect of letrazuril in the treatment of AIDS-related Cryptosporidiosis. DESIGN: A prospective, open-label study of letrazuril was performed. SETTING: The study was conducted at the Immune Deficiency Treatment Centre (IDTC) of Montreal General Hospital, a tertiary-care centre with inpatient and outpatient facilities. PARTICIPANTS: All HIV-positive patients presenting to the IDTC between November 1991 and January 1993 who had symptomatic intestinal Cryptosporidiosis were enrolled in this protocol. Sixteen participants entered the study and 15 were available for evaluation, having completed at least 2 weeks on the study medication. INTERVENTIONS: Patients received letrazuril daily in escalating doses of 50 to 100 mg orally for 6 weeks. Clinical and laboratory evaluations were performed weekly during the treatment phase, with a follow-up evaluation 4 weeks after the end of this phase, for a total study period of 10 weeks. MAIN OUTCOME MEASURES: Response to letrazuril was assessed by eradication of Cryptosporidial oocysts from the stool and symptomatic improvement in diarrhoea and abdominal pain. Haematological, biochemical, and electrocardiographic parameters were also studied to evaluate potential toxicities of the treatment. RESULTS: Fourteen evaluable patients had baseline CD4 lymphocyte counts ranging from 3 to 99 x 10(6)/l cells (mean, 30 x 10(6)/l cells). (The fifteenth evaluable patient had a CD4 count 235 x 10(6)/l.) Of these 14 patients, five showed a major response (symptomatic improvement and eradication of Cryptosporidial oocysts from the stool), two had a minor response (symptomatic improvement with persistence of oocysts in stool), and seven had no response to therapy with letrazuril. Seven patients developed a transient drug-related rash. CONCLUSION: Fifty per cent of the AIDS patients in this study experienced an improvement in their Cryptosporidial disease while receiving letrazuril. No serious dose-related toxicities were observed. Larger Phase II trials are needed to evaluate the safety and efficacy of letrazuril in AIDS-associated intestinal Cryptosporidiosis.

AIDS-Related Opportunistic Infections↗

PubMed1993

Regional cerebral blood flow changes in stroke imaged by Tc-99m HMPAO SPECT with corresponding anatomic image comparison.

Cerebral infarction is the result of cerebrovascular insufficiency and itself creates complex changes in cerebral hemodynamics. To allow recognition of patterns of change in regional cerebral blood flow (r-CBF) caused by cerebral infarction, the authors present an atlas of Tc-99m hexamethylpropyleneamine oxime (Tc-99m HMPAO) SPECT brain scan sections for a variety of strokes demonstrating typical vascular territorial involvements and evolution of morphologic and r-CBF change. Sections from MRI or CT are shown with SPECT images of the stroke lesion for comparison of the complementary information provided by regional cerebroperfusion and by morphology. Examples of SPECT during acute, subacute, and chronic stages of stroke are provided. To illustrate the temporal evolution of stroke and accompanying changes in the "stroke penumbra," case examples of acute tissue necrosis, luxury perfusion, ischemia, and diaschisis are presented. Methods for semiquantitative analysis of morphologic versus r-CBF defect size after acute stroke are described. How brain SPECT scans conducted during Diamox initiated cerebrovascular stress tests can complement the information obtained from baseline studies and assist in the interpretation of r-CBF abnormalities is also demonstrated.

Adult↗

PubMed1992

Glycoconjugates are stage- and position-specific cell surface molecules in the developing olfactory system, 1: The CC1 immunoreactive glycolipid defines a rostrocaudal gradient in the rat vomeronasal system.

Primary sensory neurons in the vomeronasal organ (VNO) project axons to the glomeruli of the accessory olfactory bulb (AOB) where they form connections with mitral cell dendrites. We demonstrate here that monoclonal antibodies to specific carbohydrate antigens define stage- and position-specific events during the development of the vomeronasal system (VN). CC1 monoclonal antibodies react with specific N-acetyl galactosamine containing glycolipids. In the embryo, CC1 antigens are expressed throughout the VNO and on vomeronasal nerves. Beginning approximately at birth and continuing into adults, CC1 expression is spatially restricted in the VNO to centrally located cell bodies. In the postnatal AOB, CC1 is expressed in the nerve layer and glomeruli, but only in the rostral half of the AOB. These data suggest that CC1 antigens may participate in the targeting of axons from centrally located VNO neurons to rostral glomeruli in the AOB. In contrast, CC2 monoclonal antibodies, which recognize complex alpha-galactosyl and alpha-fucosyl glycoproteins and glycolipids, react with all VNO cell bodies and VN nerves from embryonic (E) day 15 to adults. CC2 antibodies do not distinguish rostral from caudal regions of the AOB, nor are the CC2 glycoconjugates developmentally regulated. P-Path monoclonal antibodies, which recognize 9-O-acetyl sialic acid, react with cell bodies in the VNO and nerve fibers from E13 to postnatal (P) day 2. P-Path immunoreactivity disappears from the VNO system almost completely by P14, when only a few P-Path reactive nerve fibers can be seen. These studies suggest that specific cell surface glycoconjugates may participate in spatially and temporally selective cell-cell interactions during development and maintenance of vomeronasal connections.

Animals↗

PubMed1992

Glycoconjugates are stage- and position-specific cell surface molecules in the developing olfactory system, 2: Unique carbohydrate antigens are topographic markers for selective projection patterns of olfactory axons.

Three monoclonal antibodies specific for different carbohydrate antigens were used to analyze the development of the olfactory system in rats. CC2 antibodies react with a subset of main olfactory neurons, their axons, and terminals in the olfactory bulb. CC2 antigens are expressed on dorsomedial neurons in the olfactory epithelium (OE) from embryonic (E) day 15 to adults. In the olfactory bulb (OB), only dorsomedially located glomeruli express CC2 glycoconjugates from postnatal day (P) 2 to adults. Thus CC2 defines a dorsomedially organized projection that is established early in embryonic development and continues in adults. P-Path antibodies react with antigens that are expressed on the olfactory nerve in embryos, and are also detected on cell bodies in the neuroepithelium and in glomeruli of the OB at P2. At P14, P-Path staining is weaker, but remains present on many cells in the epithelium and in many glomeruli in the bulb. Postnatally, P-Path immunostaining continues to decrease in most regions of the OE and OB. At P35 and afterwards, only a few P-Path-positive neuronal cells can be detected in the OE. Furthermore, after P35 only two groups of glomeruli in the OB are P-Path immunoreactive. One is situated adjacent to the accessory olfactory bulb (AOB) at the dorsocaudal surface of the OB. The other is adjacent to the AOB at the ventrocaudal surface of the OB. Thus, in adults, P-Path glycoconjugates are expressed in neurons and axons that project only to a specific subset of caudal glomeruli of the OB. Monoclonal antibody 1B2, reacts with beta-galactose-terminating glycolipids and glycoproteins. At P2, 1B2 immunoreactivity is seen on a subset of cell bodies that are distributed throughout the OE and is expressed in most glomeruli in the OB at this age. By P35 and in adults, 1B2 continues to be expressed on a subset of neurons in the OE that project to only a small subset of glomeruli in the OB. Unlike CC2 and P-Path antigens that define specific groups of glomeruli, 1B2-immunoreactive glomeruli do not have a detectable spatial pattern. It is more likely that 1B2 antigens define a specific stage in the maturation of connections between the OE and OB.

Animals↗

PubMed1992

A monoclonal anti-glycoconjugate antibody defines a stage and position-dependent gradient in the developing sympathoadrenal system.

The expression of complex carbohydrate antigens was analysed in developing sympathoadrenal cells of the rat using monoclonal antibodies that react with unique carbohydrate structures. CC1 and CC4 are monoclonal antibodies that react specifically with beta-N-acetylgalactosamine and alpha-galactose/alpha-fucose moieties, respectively. CC1-reactive glycoconjugates are expressed in embryonic superior cervical ganglion (SCG) cells as early as embryonic day 15 (E15). CC4 is expressed in the SCG only for a brief period starting at E18 and then disappearing at P5. During their transient period of expression, CC1 antigens are expressed uniformly throughout the SCG at E15-17, but are then restricted to the rostral portion of the SCG from E18 to P4. CC4 is also concentrated in the rostral portion of the SCG between E21 and P4. In the adrenal medulla, CC1 and CC4 antigens display a post-natal onset of expression commencing approximately at P14 and continue to be expressed on a subset of cells which contain tyrosine hydroxylase (TH). The expression of CC1, however, is restricted to phenylethanolamine-N-methyltransferase-(PNMT)-negative chromaffin cells, whereas CC4 is not. CC1 and CC4-expressing cells appear to be scattered throughout the adrenal medulla without any particular topographic orientation. These findings suggest that the CC1 monoclonal antibody defines a stage-specific differentiation antigen in the sympathoadrenal lineage. Additionally, the CC1 antigen may confer important positional information in the embryonic SCG by distinguishing rostral from caudal neuronal cell bodies.

Adrenal Medulla↗

PubMed1992

Improving communication with oncology patients: taping the consultation.

Patients are often dissatisfied with the information provided for them by doctors. A simple cheap method of improving communication by tape recording the initial consultation with oncology outpatients is described. Analysis of 100 taped consultations by a subsequent questionnaire revealed that patients and their relatives claimed enormous benefit from the opportunity to hear the consultation again.

Adult↗

PubMed1990

Effects of nitrous oxide on global and regional cortical blood flow.

We conducted regional cortical blood flow studies using the xenon-133 clearance technique on 12 volunteers during the administration of 25% and 50% N2O and during baseline conditions (breathing room air or 100% O2). Global cortical blood flow was very highly significantly increased above baseline measures in all subjects by 50% N2O (mean increase 37% above 100% O2 condition). A smaller but still significant increase was observed with 25% N2O. Analysis of regional cortical blood flow revealed heterogeneity in the pattern of changes; that is, the baseline pattern was altered by the inhalation of N2O, most often resulting in an accentuation of relative frontal blood flow. The anterior-posterior gradient in N2O-induced blood flow changes differs from that observed with simple vasodilatory agents, such as CO2, with which the increase is purely systemic and the baseline pattern is preserved. This indicates that N2O has differential effects on cerebral metabolism that may well reflect the typical alterations in experiential state reported by subjects.

Adult↗

PubMed1988

Evidence for right-hemisphere involvement in recovery from aphasia.

Cortical evoked potentials and dichotic listening test scores were used to assess the extent of activation of the two cerebral hemispheres during various language tasks in a group of 21 recovering aphasics, 15 nonaphasic patients with right-hemisphere stroke, and 17 normal volunteers. In agreement with previous findings, both measures suggest greater right-hemisphere activation during language processing in the recovering aphasics than in nonaphasic patients and normal subjects. These data support the view that restitution of language entails reorganization of brain function with increased participation of the nondominant hemisphere.

Aphasia↗

PubMed1988

Visuospatial tasks compared via activation of regional cerebral blood flow.

Regional cerebral blood flow was measured in 19 subjects during the performance of three tasks thought to primarily involve right hemisphere processing: judgement of line orientation, mental rotation of three-dimensional cube arrays, and a fragment puzzle task. Asymmetries in hemispheric flow (right side greater) were only observed in the line orientation and rotation conditions and were present in both sexes. The magnitude of the asymmetry was greater in the rotation task which also showed an asymmetry in parietal flow. Thus mental rotation placed the most asymmetric demand on cerebral resources. This provides a task that more reliably activates the right hemisphere than those previously reported and suggests a truly "mental manipulative" aspect to right hemisphere advantage in visuospatial performance.

Adult↗

PubMed1987

Convergent evoked potential and cerebral blood flow evidence of task-specific hemispheric differences.

Two independent measures of cerebral activation, probe evoked potentials (EPs) and regional cerebral blood flow (rCBF) were used to assess the relative contribution of the left and right parietal areas during a task requiring mental rotation of geometric figures. The objective of the study was to ascertain the degree of concordance in these two measures in revealing task-specific hemispheric activation. Since rCBF is a direct measure of regional metabolic rate and has been shown to reflect expected task-specific hemispheric asymmetries, its concordance with probe EP data could serve to validate the assumptions underlying interpretation of the latter. EPs to strobe flashes and rCBF were simultaneously measured in 19 dextral normal adults during a mental rotation task and during a control task involving similar stimulation and response requirements. A high degree of concordance in these two measures was obtained, with both revealing significantly greater activation of the right parietal region during the mental rotation task. Besides supporting the notion of predominant right hemisphere involvement in this type of visuo-spatial operation, this study suggests that either measure may be used as a reliable index of task-specific regional cerebral asymmetries.

Adult↗

PubMed1987

Frontal blood flow changes in recovery from coma.

Two-dimensional studies of cortical blood flow were conducted in 20 closed head injury patients in a comatose state and subsequently in 9 patients as they recovered to an awake and responding state. Comatose patients showed a reduction of frontal flow compared to the resting pattern observed in age matched normal volunteers. In most patients the normal anterior-to-posterior flow gradient was reversed. Increases in global flow, while in coma, tended to exaggerate this reversal. Patients who survived showed a normalization of the regional flow pattern as they regained consciousness. The marked reduction of frontal blood flow in the comatose state was independent of locus of injury as determined by computed tomography (CT) scan data. Combined with previous CBF studies of sensory and cognitive activation, these findings suggest that frontal reduction may be a nonspecific effect of any state or condition involving reduced directed mental activity. This, in turn, raises questions about recent interpretations offered for frontal CBF reduction in psychiatric disease.

Adult↗

PubMed1987

Cerebral blood flow in severity-matched Alzheimer and multi-infarct patients.

Cerebral blood flow was studied in patients meeting research criteria for either Alzheimer's disease or multi-infarct dementia, matched for age and severity of dementia. In both groups, mean flow was less than in age-matched normal controls, but the Alzheimer patients also had significantly lower mean flow than the multi-infarct group. This result helps resolve discrepancies found in studies with inadequate control for severity. Either global flow or regional left parietal flow could be used to discriminate between these dementia categories with 87% accuracy.

Aged↗

PubMed1987

Cerebral blood flow evidence of right frontal activation in attention demanding tasks.

Having noticed a consistent activation of right frontal areas during several visuospatial tasks, we retrospectively examined data from 121 regional cerebral blood flow (rCBF) studies conducted under a variety of conditions involving different stimuli, response modes and task requirements. These were compared to scans conducted while subjects were at rest. Significant hemispheric differences were found for all tasks combined in the frontal regions, where right flow was greater than left, especially in more demanding tasks. This finding suggests a very general role for the right hemisphere in attention or vigilance.

Adult↗

PubMed1986

CBF gradient changes elicited by visual stimulation and visual memory tasks.

Normal volunteers underwent three successive scans of regional cerebral blood flow (rCBF) using the 133Xe inhalation technique during visual stimulation, a recognition memory task and a resting state defined by high EEG alpha content. Since the stimulation was virtually identical in both non-rest conditions, we were able to separate the CBF pattern resulting from simple stimulation and that resulting from the cognitive (recognition memory) component alone. These turned out to have very nearly opposite effects on the normal anterior-to-posterior resting state gradient: the sensory component diminished the gradient, while the cognitive component exaggerated it. It is suggested that these normative data can be of clinical value in the study of cerebral recovery/reorganization following post-traumatic amnesia.

Adult↗