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Biomedical subjects

J Clinton

Publications and source records attributed to J Clinton.

At least 19 recordsLinked to original sources
PubMed2001

Emergency department right upper quadrant ultrasound is associated with a reduced time to diagnosis and treatment of ruptured ectopic pregnancies.

OBJECTIVE: To determine whether the time to diagnosis and treatment of patients with ruptured ectopic pregnancy is significantly less for patients who had emergency department (ED) right upper quadrant (RUQ) ultrasound (US) compared with those who had US in the radiology department. METHODS: The authors conducted a retrospective review of eligible patients presenting to an urban ED between January 1990 and December 1998. Patients were included in the study if they were seen in the ED, had a discharge diagnosis of ruptured ectopic pregnancy, were brought immediately to the operating room after a definitive diagnosis of ectopic pregnancy rupture was made, and had more than 400 mL of intraperitoneal blood found at the time of surgery. The ED, hospital, radiology, and operative records were reviewed to determine presenting vital signs, intraperitoneal blood loss, time to diagnosis, time to treatment, and type of US performed. RESULTS: There were 37 patients enrolled; 16 received ED RUQ US (group I) and 21 had a formal US in radiology (group II). The ages, pulses, systolic blood pressures, and volumes of hemoperitoneum were similar between the two groups. The average time to diagnosis from ED arrival was 58 minutes for group I (SD = 57; 95% CI = 28 to 87) and 197 minutes for group II (SD = 82; 95% CI = 162 to 232) (p < or = 0.0001). The average time to operative treatment was 111 minutes (group I) (SD = 86; 95% CI = 69 to 153) and 322 minutes (group II) (SD = 107; 95% CI = 270 to 364) (p < or = 0.0001), respectively. CONCLUSIONS: Patients with ruptured ectopic pregnancy, who were selected to have RUQ US performed in the ED by emergency physicians, had an average decrease in time to diagnosis of two and a quarter hours, and an average decrease in time to treatment of three and a half hours, compared with those having a formal pelvic US in the radiology department. Further prospective investigation is needed to determine whether ED RUQ US can safely expedite care of patients with suspected ectopic pregnancy.

Adult↗
PubMed1994

Differential synaptic loss in the cortex in Alzheimer's disease: a study using archival material.

We have developed techniques to utilize immunocytochemical localization of synaptic protein (SNAP-25) in conjunction with image analysis to investigate synaptic loss in readily available archival material. Sections from 5 cortical regions were examined in cases of Alzheimer's disease (n = 7) and controls (n = 5). Image analysis was used to determine a relative synaptic index (RSI) and probe for changes in synaptic integrity. RSI value for cortical regions did not differ in controls. RSIs from sulci and gyri were significantly correlated in Brodmann areas 6, 9 and 18 (40 and 52 approached significance). Cases with Alzheimer's disease showed decreases in sulcal and gyral RSI values of between 60% (Brodmann area 6 < 0.01) and 10% (Brodmann area 18 > 0.4) and a lack of correlation in sulco-gyral values except in Brodmann area 18. We have demonstrated that synaptic pathology is heterogeneous with frontal cortex most and occipital cortex least affected. Sulci and gyri are affected to different degrees. The underlying cytoarchitecture of the cortex and its pattern of connectivity appears to have a considerable influence on the degree and extent of synaptic pathology.

Aged↗
PubMed1994

Synaptophysin gene expression in human brain: a quantitative in situ hybridization and immunocytochemical study.

Synaptophysin is a presynaptic vesicle protein. Its quantitative detection has become established as a molecular marker of synaptic density. We have studied synaptophysin messenger RNA in the neocortex, hippocampus and cerebellum using in situ hybridization histochemistry to see if the encoding transcript can be detected in post mortem human brain and to investigate factors which might influence its abundance. Synaptophysin was also measured immunocytochemically in the hippocampus. The level of synaptophysin messenger RNA expression was uniform in all neocortical areas examined. Strong correlations were found for the amount of synaptophysin messenger RNA between individual regions and between homologous areas in the two hemispheres. Synaptophysin messenger RNA declined with increasing age and prolonged post mortem interval. Synaptophysin immunoreactivity also reduced with age, as well as with duration of formalin fixation but not post mortem interval. Synaptophysin immunoreactivity correlated with the abundance of the messenger RNA in neurons within, and projecting to, each hippocampal subfield. Significantly greater synaptophysin immunoreactivity was seen in the left than the right CA4 and CA1 regions. These data show that quantitative detection of synaptophysin messenger RNA as well as synaptophysin itself can reliably be carried out in post mortem human brain sections. They are in keeping with other findings that synaptic density is relatively uniform through the neocortex and decreases with age. They also suggest a possible asymmetry of hippocampal synaptophysin expression. The level of synaptophysin messenger RNA paralleled that of synaptophysin immunoreactivity, indicating that changes in gene expression contribute to variations in the latter observed in aging and other situations. Detection of synaptophysin messenger RNA broadens the range of methods by which synaptic protein gene products can be studied and used as markers of synaptic density and synaptic involvement during physiological and pathological processes in human brain.

Adult↗
PubMed1994

Emergency department two-dimensional echocardiography in the diagnosis of nontraumatic cardiac rupture.

Myocardial rupture is a catastrophic complication of acute myocardial infarction that usually results in sudden death. If diagnosed quickly, patients with myocardial rupture may be salvaged. This report describes the application of emergency department two-dimensional echocardiography in the diagnosis of six cases of myocardial rupture over two years. Each demonstrated a characteristic hemopericardium on limited single-window examination. These included four patients who met institutional guidelines for thrombolytic therapy. Three patients survived surgical repair, with two long-term survivors.

Aged↗
PubMed1993

Frontal lobe dementia is not a variant of prion disease.

Frontal lobe dementia (FLD) is a syndromal diagnosis with a variable pathology. It has been argued that FLD is a dementing disorder which should be nosologically and etiologically distinguished from other types of dementia. However, similarities with prior disease and Alzheimer's disease have led to the suggestion that FLD is a variant of one or other of these dementias. We have tested this line of argument by examining the frontal cortex and cerebellum of 14 FLD cases and probing the molecular pathology using well characterized antibodies to prion protein and beta-amyloid protein. No prion protein deposits or significant levels of beta-amyloid protein were detected. FLD is a dementing disorder whose molecular pathology, whilst as yet uncharacterised, can be distinguished from those of other dementing disorders.

Aged↗
PubMed1993

Synaptic degeneration is the primary neuropathological feature in prion disease: a preliminary study.

The range of neuropathology found in cases of prion disease is considerable. The pathology present in dendrites and axons is associated with a marked loss of spines and synaptic contacts. It is probable that this loss underlies the functional and neurological deficits in the disease. Immunocytochemical re-examination of 2 cases of inherited disease with a 144 bp prion gene insertion with no characteristic pathology (i.e. spongiform change, astrocytosis and gliosis), together with 3 typical cases of prion disease (CJD), with antibodies to synaptophysin and synaptic protein demonstrated the presence of synaptic "plaque-like" lesions throughout the temporal cortex and cerebellum. In addition, examining the tissue by image analysis demonstrated a greater than 30% reduction in the relative synaptic index in all the prior disease cases when compared with controls. Synaptic disorganization and/or loss is a fundamental and constant feature of prion disease, irrespective of the presence or absence of spongiform change, neuronal loss and severe gliosis. Assessment of the extent and location of synaptic deficits might produce a more accurate documentation of the degree of neuronal disorganisation occurring during the course of prion disease.

Adult↗
PubMed1993

Differential pattern of beta-amyloid protein deposition within cortical sulci and gyri in Alzheimer's disease.

We have quantified the pattern of beta-amyloid protein (beta AP) deposition in the sulci and gyri of the frontal cortex in Alzheimer's disease. The distribution pattern in the frontal cortex gyri is unequivocally different from the pattern found in the frontal sulci. These findings, in conjunction with our previous studies, reflect a differential vulnerability between the sulci and the gyri with respect to Alzheimer's disease pathology, sulci being affected to a greater extent. It is probable that the different patterns of deposition relate to the underlying cytoarchitecture of the cortex.

Alzheimer Disease↗
PubMed1992

Prion protein immunocytochemistry helps to establish the true incidence of prion diseases.

Creutzfeldt-Jakob disease (CJD) and Gerstmann-Strüssler-Scheinker disease (GSSD) are transmissible spongiform encephalopathies or prion diseases affecting man. It has been reported that prion diseases may occur without the histological hallmarks of spongiform encephalopathies: vacuolation of the cerebral grey matter, neuronal loss and astrocytosis. These cases without characteristic neuropathology may go undiagnosed and consequently the true incidence of transmissible dementias is likely to have been under-estimated. Immunocytochemistry using antibodies to prion protein gives positive staining of these cases, albeit the pattern of immunostaining differs from that seen in typical forms. Accumulation of prion protein is a molecular hallmark of prion diseases, and thus a reproducible, speedy and cost-efficient immunocytochemical screening of unusual dementias may help to establish the true incidence of prion diseases.

Adult↗
PubMed1992

Quantification of beta A4 protein deposition in the medial temporal lobe: a comparison of Alzheimer's disease and senile dementia of the Lewy body type.

The distribution of beta-amyloid protein (beta A4) was examined in the medial temporal lobes from cases of Alzheimer's disease (AD) (n = 13), senile dementia of Lewy body type (SDLT) (n = 12) and age matched controls (n = 9). Using a previously described image analysis technique the extent of beta A4 pathology was determined in ten distinct anatomical sites within the medial temporal lobe. AD and SDLT cases contained very similar amounts of beta A4 in the areas sampled and both contained significantly more beta A4 than the age matched controls, particularly in the dentate and parahippocampal gyri. The similarity of the beta A4 load in the two conditions is in contrast to reported differences in the number of neurofibrillary tangles which can be observed. It is suggested that AD and SDLT represent a spectrum of pathology which centres around the aberrant processing of the beta A4 precursor protein.

Aged↗
PubMed1992

Quantifying the pattern of beta/A4 amyloid protein distribution in Alzheimer's disease by image analysis.

We have undertaken a study of the distribution of the beta/A4 amyloid deposited in the cerebral cortex in Alzheimer's disease. Previous studies which have examined the differential distribution of amyloid in the cortex in order to determine the laminar pattern of cortical pathology have not proved to be conclusive. We have developed an alternative method for the solution of this problem. It involves the immunostaining of sections followed by computer-enhanced image analysis. A mathematical model is then used to describe both the amount and the pattern of amyloid across the cortex. This method is both accurate and reliable and also removes many of the problems concerning inter and intra-rater variability in measurement. This method will provide the basis for further quantitative studies on the differential distribution of amyloid in Alzheimer's disease and other cases of dementia where cerebral amyloidosis occurs.

Alzheimer Disease↗
PubMed1991

Post-traumatic Alzheimer's disease: preponderance of a single plaque type.

The cause of Alzheimer's disease is unknown. Several factors have been proposed including head trauma. At present, the link between head injury and a subsequent neurodegenerative process is largely circumstantial, except in the case of dementia pugilistica (punch drunk syndrome) found in boxers. Recent studies have shown that the brains of boxers with this syndrome contain large numbers of 'diffuse' beta-protein immunoreactive plaques. We supposed that this plaque type might be associated with trauma induced Alzheimer-like degeneration. In order to test this hypothesis we have re-investigated a previously reported case of post-traumatic premature Alzheimer's disease. Immunocytochemistry using antibodies to amyloid beta-protein revealed large numbers of 'diffuse' non-Congophilic plaques with little or no neuritic component. A similar preponderance of this plaque type is present in the brains of boxers with dementia pugilistica. Our observations support the idea of a trauma induced Alzheimer-like degenerative process and indicate that such a condition is associated with a marked preponderance of 'diffuse' plaques.

Adult↗
PubMed1989

A comparison of open peritoneal lavage with modified closed peritoneal lavage in blunt abdominal trauma.

A randomized prospective study compared open peritoneal lavage using a peritoneal dialysis catheter with modified closed lavage using either the Lazarus-Nelson or Cook lavage catheter. The time required to perform the lavage, technical difficulties, complications, and accuracy were assessed in 63 adult victims of blunt abdominal trauma. The average time to perform lavage was 21.1 minutes for open lavage, 14.7 minutes for Lazarus-Nelson closed lavage, and 9.8 minutes for Cook closed lavage. The closed technique using the Cook catheter was significantly faster than open lavage. Technical difficulties were significantly less frequent with Cook catheter closed lavage than with Lazarus-Nelson catheter closed lavage. The overall complication rate was 1.8%, and the overall accuracy was 98.1%, without apparent difference among techniques. It is concluded that, when no contraindications to closed lavage exist, and when time is of importance, closed lavage with the Cook catheter is the preferred technique.

Abdominal Injuries↗
PubMed1989

The external rotation method for reduction of acute anterior shoulder dislocation.

Acute anterior shoulder dislocation is a common disorder confronting the emergency physician. Traditional methods of reduction are often technically difficult, time consuming, and painful to the patient. Furthermore, they frequently require more than one physician and occasionally exacerbate the injury. Conversely, the recently described method of reduction by external rotation is a reliable and safe method. A single physician performs the reduction rapidly and patients tolerate it well.

Emergencies↗