The proximo-distal spread of axonal degeneration in the dorsal columns of the rat

Summary The pivotal event in Wallerian degeneration is the breakdown of the axon. Establishing the pathophysiology of axonal degeneration has implications for the understanding of the pathogenesis of other types of nerve degenerations. A key aspect of the pathophysiology is the spatiotemporal pattern of spread after transection, an issue that has remained controversial. We have studied the progression of axonal degeneration in the dorsal columns of the rat following L₄L₅L₆ dorsal radiculotomy. Axonal degeneration proceeds in a proximo-distal fashion, beginning near the site of transection and spreading up the dorsal columns at a net rate of about 3 mmh^–1. In addition, there was early degeneration of the preterminal axons in the gracile nuclei. This pattern suggests that the clearing of axonally transported materials from the distal stump by continued anterograde transport may underlie axonal breakdown after transection.     

Risk factors for HIV-1 seroconversion among injection drug users: a case-control study.

OBJECTIVES. A nested case-control study was conducted in Miami, Fla, to determine risk factors associated with human immunodeficiency virus type 1 (HIV-1) seroconversion among injection drug users. METHODS. The study identified 21 incident cases of HIV-1 infection and 76 unmatched controls from two longitudinal cohorts of injection drug users. One cohort consisted of individuals who originally had been recruited from treatment centers; a second cohort was recruited from the "street." Logistic regression analyses that adjusted for age, gender, and race were performed. RESULTS. The final model determined that the primary independent risk factor that best explained the risk for seroconversion was sharing injection equipment in the year prior to conversion; a marginal risk factor was presence of sexually transmitted disease during this same period. CONCLUSIONS. Both an injection component and a sexual component play a role in seroconversion among injection drug users, although the injection component is much stronger.     

Food-related illness and death in the United States.

To better quantify the impact of foodborne diseases on health in the United States, we compiled and analyzed information from multiple surveillance systems and other sources. We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Known pathogens account for an estimated 14 million illnesses, 60, 000 hospitalizations, and 1,800 deaths. Three pathogens, Salmonella, Listeria, and Toxoplasma, are responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents account for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths. Overall, foodborne diseases appear to cause more illnesses but fewer deaths than previously estimated.     

Quality of diagnostic services for cancer: a comparison of open access and conventional outpatient clinics.

OBJECTIVE AND STUDY DESIGN: To assess quality of a quick and early diagnosis route (QED) by determining effectiveness and cost-effectiveness of five clinics compared with three conventional outpatient clinics. Prospective economic evaluation. Six-month cohort of all referrals (November 1996-April 1997). SUBJECTS: All referrals for suspected cancers of: upper gastro-intestinal tract; urinary tract, prostate and testis; skin. EFFECTIVENESS: Median days saved between GP referral and date of: diagnostic appointment; consultant decision; intervention. RESULTS: GP referral to diagnostic appointment: QED was effective (median days) for all clinics. Diagnostic appointment to consultant decision: QED was effective for testicular and haematuria clinics. Consultant decision to intervention: QED was effective for haematuria, testicular and melanoma clinics. COST-EFFECTIVENESS: Extra (incremental) NHS cost per patient diagnosed. RESULTS: Less than 5 Pounds per day saved between GP referral and diagnostic appointment for: endoscopy; haematuria; prostate; testicular; melanoma. Less than 3 Pounds per day saved between GP referral and consultant decision for: testicular; haematuria. Less than 3 Pounds per day saved between GP referral and intervention for: endoscopy; haematuria; testicular; melanoma. CONCLUSION: A "quick and early" diagnostic route provides a higher quality service through improved effectiveness and cost-effectiveness compared to conventional outpatients.     

Cerebral spinal fluid involvement by Hodgkin's disease diagnosed by CSF cytology and immunocytochemistry

A 39-yr-old man with stage IV Hodgkin's disease (HD) involving bone marrow was being evaluated for autologous bone marrow transplantation when he developed diplopia, prompting a lumbar puncture tap for cerebral spinal fluid (CSF) examination. Cytologic examination of the CSF revealed numerous Reed-Sternberg (RS) cells in a polymorphous inflammatory background of small lymphocytes, monocytes, rare plasma cells, and eosinophils. However, magnetic resonance imaging (MRI) studies of the brain and spinal cord failed to reveal evidence of leptomeningeal disease or intracranial masses. Repeat CSF examination again demonstrated cytologic evidence of HD. Immunocytochemical stains established that the RS cells and mononuclear Hodgkin's cells were positive for CD30 and CD20 but negative for CD15; this phenotype was identical to that of RS cells in the initial diagnostic bone marrow biopsy, confirming CSF involvement by HD. The patient was treated with intrathecal methotrexate, 15 mg, 6 days after his bone marrow transplant. After treatment, all subsequent CSF cytology specimens were negative for tumor. In this case of disseminated HD, cytologic examination allowed for early detection of CNS involvement by lymphoma prior to development of radiographically detectable lesions.     

Alterations in synaptic proteins and their encoding mRNAs in prefrontal cortex in schizophrenia: a possible neurochemical basis for 'hypofrontality'

An impairment of prefrontal cortical functioning in schizophrenia ('hypofrontality') has been suggested by clinical, neuroimaging, and postmortem brain tissue studies. We used Western immunoblot and Northern hybridization analyses of postmortem brain tissue obtained from 14 schizophrenic patients and 12 control patients of similar ages to measure tissue levels of synaptophysin (a structural synaptic vesicle protein) and of SNAP-25 (a 25-kDa presynaptic protein), and their encoding mRNAs, in Brodmann's area 10 of prefrontal cortex. There were significant decreases in tissue levels of both of these proteins in prefrontal cortex of schizophrenic patients relative to controls. In contrast, tissue levels for the mRNAs encoding these proteins were not decreased in schizophrenic patients. Subsequent labeling of the same Western immunoblots showed no difference in tissue levels of glial fibrillary acidic protein (GFAP) in schizophrenic and control patients. Similarly, subsequent hybridization of the same Northern hybridization membranes showed no difference in tissue levels of GFAP mRNA or of 28S rRNA in schizophrenic and control patients. These alterations in tissue levels of synaptophysin and SNAP-25 are consistent with the idea that the clinically observed 'hypofrontality' of schizophrenia arises from abnormalities of synaptic number or structural integrity in prefrontal cortex.     

Transhiatal approach to total gastrectomy for adenocarcinoma of the gastric cardia

BACKGROUND: A thoracoabdominal approach has traditionally been described for the resection of tumours of the gastric cardia. The aim of this study was to evaluate a transhiatal approach for resection of cancers of the gastric cardia. METHODS: Twenty consecutive patients undergoing transhiatal gastro-oesophagectomy for cancer of the gastric cardia were studied. Data were collected prospectively with regard to operating time, operative blood loss, intensive care unit (ICU) stay, analgesia use, duration of hospital stay, and pathological details of resection margin clearance and lymph node yield. Results were compared with those of the 20 preceding patients for whom the same prospective information had been recorded following resection via the standard thoracoabdominal approach. RESULTS: The transhiatal approach required a shorter operating time (median 190 (range 105-255) versus 280 (225-330) min; P = 0.004). It resulted in less blood loss (median 405 (180-2000) versus 1000 (420-3200) ml; P = 0.03) and fewer days in the ICU (median 0 (0-31) versus 2 (1-8) days; P = 0.005) despite being performed in an older patient population (median 71 (43-78) versus 63 (59-70) years; P = 0.016). There was no difference in either the lymph node harvest or length or involvement of upper resection margins. CONCLUSION: The transhiatal approach to the resection of tumours at the gastric cardia is a valid and safe alternative to the standard thoracoabdominal technique. This technique avoids thoracotomy and its associated morbidity and is accompanied by reduced blood loss, decreased operating time and a shorter ICU stay.