Spontaneous splenic infarction secondary to diabetes-induced microvascular disease

Splenic infarction is a clinical entity seldom encountered. The most frequent causes of splenic infarction include thromboembolic phenomena, hematologic malignant neoplasms, and vasculitides. We describe a patient who sustained splenic infarction secondary to diabetes-induced, small-vessel atherosclerotic disease.

Compositional analysis of glyphosate-tolerant soybeans treated with glyphosate

The compositional analyses and safety assessment of glyphosate-tolerant soybeans (GTS) were previously described. These analyses were extensive and included addressing the potential effects on seed composition from the genetic modification. Detailed compositional analyses established that GTS, which had not been treated with glyphosate, were comparable to the parental soybean line and to other conventional soybeans. In this study, two GTS lines, 40-3-2 and 61-67-1, were treated with commercial levels of glyphosate, the active ingredient in Roundup herbicide. The composition of the seed from soybeans sprayed with glyphosate was compared to that of a nonsprayed parental control cultivar, A5403. The nutrients measured in the seed included protein, oil, ash, fiber, carbohydrates, and amino acids. The concentration of isoflavones (also referred to as phytoestrogens) was also measured as these compounds are derived from the same biochemical pathway that was engineered for glyphosate tolerance. The analytical results from these studies demonstrate that the GTS soybeans treated with glyphosate were comparable to the parental soybean cultivar, A5403, and other conventional soybean varieties.

Evaluation of echocardiography in the management of elderly patients with heart failure

OBJECTIVE

To determine the validity of a clinical diagnosis of systolic dysfunction in elderly patients with heart failure and assess the contribution of echocardiography to their management.

SUBJECTS

61 elderly patients with a diagnosis of heart failure in a geriatric assessment unit setting.

METHODS

Prospective study determining sensitivity, specificity and predictive values of a clinical and radiological diagnosis compared with echocardiographic standard. Proposed management was compared before and after echocardiography.

RESULTS

Clinical assessment was highly sensitive (93%) but lacked specificity (32%). Combining radiological and clinical diagnoses increased specificity to 58%. Echocardiography revised the lead cardiac diagnosis for 28% of patients and influenced patient management plans for 41%.

CONCLUSION

For elderly patients with heart failure, echocardiography improves diagnostic accuracy and identifies those patients with potential to benefit from angiotensin-converting enzyme inhibitors.

Sample collection and clinical pathology of reptiles

Clinical pathology techniques can guide the clinician to diagnose and treat the reptile patient successfully. Text, tables, pictures, and diagrams in this article describe blood and cytology collection techniques and interpretation for the common pet reptile species.

The effects of exercise intensity on post exercise hypotension

Ten normotensive, recreationally active participants aged 35.0 +/- 16.3 years, volunteered to participate in the study. Average baseline blood pressure (BP) was 132/75 mm Hg for systolic (SBP) and diastolic (DBP) pressure respectively. On two separate days, participants underwent testing in a randomised, repeated measures fashion such that they performed 30-min bouts of cycle ergometry at a power output which elicited 50 or 75% of VO2 Peak. Blood pressure was monitored continuously throughout the session by the Finapres method with 2-min windows recorded at rest, 5, 10, 15, 30, 45 and 60 min post exercise. SBP was similar between the two trials and became hypotensive at 5 through 15 min post exercise. The largest decrement (8 mm Hg) in SBP occurred 5 min post exercise. DBP was also unaffected by the intensity of exercise and was lower than before exercise at 5 and 15 through 45 min post exercise. Similarly, mean arterial pressure (MAP) showed significant decrements at 5 and 15 through 45 min post exercise irrespective of exercise intensity. Heart rate was greater during the 75% intensity than during the 50% intensity trial. Pre-exercise values were re-established by 45 min post exercise. VO2 remained significantly elevated above pre-exercise values in both trials until 15 min post exercise. Haematocrit increased significantly during both exercise bouts but returned to pre-exercise values by 10 min post exercise. This study indicates that cycle ergometry at 50 and 75% of VO2 Peak elicit similar reductions in post exercise BP. Therefore bouts of mild to moderate intensity exercise may be beneficial in the control of hypertension.

Did Wellington have too many acute psychiatric beds in 1996?

AIMS

(1) To establish whether, as believed by local clinicians, there is a shortage of acute psychiatric beds available in Wellington. (2) To compare the current situation with that of seven years ago, before the beginning of the reduction in bed numbers, as a part of deinstitutionalisation and care in the community. (3) To study the effect on occupancy of changing availability.

METHOD

Data were obtained retrospectively for the calendar years 1996 and 1989. These were examined using an analysis of variance and the results of the two years were compared.

RESULTS

There were 214 days in 1996 when there were no acute psychiatric beds available. The mean daily occupancy was 100%. Comparing like populations, there was a highly significant increase in the mean occupancy as the availability decreased from 1989 to 1996. Conversely, there was a decrease in occupancy as availability temporarily increased during 1996.

CONCLUSION

The number of acute psychiatric beds available in Wellington in 1996 was insufficient to meet the needs of the population, given the alternative resources available at that time. This is of particular concern in light of proposals to reduce the number of beds further.

The relation of p53 gene mutations to gastric cancer subsite and phenotype

OBJECTIVES

We investigated p53 gene mutations in advanced gastric cancers by direct DNA sequencing, in order to determine the frequency of mutations in gastric cancers having different epidemiological backgrounds, tumors of the cardia were compared with those arising in the antrum or corpus. Intestinal type cancers were compared with diffuse or other histologic types. We have chosen to assess the frequency of mutations solely based on DNA sequencing.

METHODS

Paraffin embedded tissues from 100 gastric cancers were evaluated. The mutational status of the p53 gene in exons 5 through 9 were determined by direct sequencing of PCR products.

RESULTS

Mutations in exons 5, 6, 7 and 8 were found in 35 of 100(35%)stomach cancers. One tumor had mutations in both exons 5 and 8. No mutations were detected in exon 9. p53 gene mutations were significantly more frequent in cancers of the cardia (19/35; 54%) than the antrum and corpus (16/65 (25%)) (p < or = 0.005). p53 mutations were more frequent in intestinal type cancers (28/67; 42%) than diffuse cancers or other histologic types of cancer (7/33; 21%), but the difference was not statistically significant.

CONCLUSIONS

Cancers of the cardia more frequently contain p53 mutations than do antral and corpus cancers, suggesting that cancers in the proximal and distal stomach evolve through different molecular pathways.

Performing CPR and holding hands. Interview by Barbara Sibbald

A while back, ER nurse Janet MacDonald was caring for an elderly woman who had suffered a small stroke. The woman was scheduled for a CT scan the next morning, but when MacDonald told her she'd have to go home she became very upset and said she was scared. Very scared. "It was like a slap in the face," says MacDonald, who realized she wasn't caring for the patient's needs, just the hospital's. The nurse in charge agreed the woman needed to stay and they found a place for her.

Calcium-PS-dependent protein kinase C and surfactant protein A in isolated fetal rabbit type II alveolar cells and surfactant-related material

The fetal lung secretes significant quantities of surfactant during late gestation to prepare for initiation of respiration at birth. However, the mechanism by which this occurs has not been determined. Since Ca2+-phosphatidylserine (PS)-dependent protein kinase C has been implicated in surfactant secretion in adult lung, the present study was done to determine whether this enzyme is also involved in the initiation of surfactant release from fetal type II cells. Type II cells isolated from gestational day-24 fetal rabbits were used. Cells were prelabelled with [32P] and [3H]choline and exposed to 4beta phorbol ester (10(-5) M) for 2 h. Secretion product and subcellular fractions were isolated by removing the culture medium, mixing with homogenate from adult rabbit lung, and subfractionating by centrifugation on a sucrose gradient. Samples of secretion product were also prepared for electron microscopy. Ca2+-PS-dependent protein kinase C was also assayed in some samples, and an add-back technique was used to determine whether enzyme activity in the intracellularly stored surfactant fraction was due to contamination. The results showed that material released by fetal type II cells after exposure to phorbol ester coprecipitated with adult rabbit lung lamellar bodies and microsomes. Morphologically, a range of forms, including lamellar-body-like structures, was detected. The released material originated largely from the lamellar body compartment of the fetal type II cells and displayed immunoreactivity with antibody to surfactant protein A (SP-A) at 35 and 70 kDa apparent molecular mass. Assay of protein kinase C in fetal type II cells showed that exposure to conditioned medium, which induces differentiation, increased activity. Incubation with phorbol ester induced translocation of activity to the microsomal fraction. Add-back assays suggested that protein kinase C activation by treatment with phorbol ester induced translocation of enzyme activity to the lamellar body fraction; none was detected prior to treatment. These results support a role for Ca2+-PS-dependent protein kinase C in initiation of surfactant release by interaction with the developing lamellar body compartment in fetal type II cells.

Naproxen does not alter indices of muscle damage in resistance-exercise trained men

PURPOSE

Unaccustomed exercise is associated with an elevated plasma creatine kinase (CK), myofibrillar inflammation, and delayed onset muscle soreness (DOMS). Nonsteroidal antiinflammatory drugs (NSAID) may attenuate DOMS and indirect indices of inflammation in humans.

METHODS

We studied the effects of an NSAID (naproxen sodium (500 mg, 2 times a day for 48 h)) taken before and after resistance exercise in eight healthy, moderately trained men in a randomized, double-blind trial. The exercise consisted of unilateral knee concentric/eccentric weight lifting with 6 sets x 10 repetitions at 80-85% of the 1 repetition maximal contraction. Muscle biopsies of each vastus lateralis (EX = exercised/REST = control) were taken 24 h after exercise for immunohistochemical staining of inflammatory cells (leukocyte common antigen). At 24 and 48 h postexercise, we also determined DOMS, plasma CK activity, and knee extensor muscle torque.

RESULTS

Exercise resulted in an increased CK activity at +24 and +48 h (vs preexercise: P < 0.01), with no treatment effect. There were no treatment effects for any of the measured variables except for a return of voluntary knee extension torque to baseline by +48 h postexercise for NSAID treatment (P < 0.05).

CONCLUSIONS

NSAID administration did not alter CK rise, muscle force deficit at 24 h postexercise, nor perceived muscle pain. In addition, the increased CK at 24 h postexercise was not associated with an acute myofibrillar inflammatory cell infiltrate in moderately trained men after resistance exercise.

A preliminary normative profile of mild traumatic brain injury diagnostic criteria

This study investigated how mild traumatic brain injury (MTBI) diagnostic and related variables present in a large, nonreferred MTBI sample. Participants were 119 adults with MTBI, drawn from consecutive admissions to two hospital emergency wards. Within 3 weeks of injury, they were asked how the 1993 American Congress of Rehabilitation Medicine MTBI diagnostic criteria and related phenomena presented in their particular cases. Results showed that retrograde amnesia was not reported or was generally very brief; retrograde amnesia was not reported unless posttraumatic amnesia was also reported; and the median ratio of posttraumatic amnesia to retrograde amnesia duration, when both were reported, was 300:1. These and other data provide a preliminary normative profile of such MTBI phenomena, and can help with differential diagnosis of MTBI in individual cases.

Immunoaffinity resin for purification of urinary leukotriene E4

Urinary leukotriene E4 (LTE4) has been used as an index of total leukotriene synthesis. A wide variety of methods have been applied to measure LTE4 which has made direct comparison of urinary levels reported by different laboratories difficult. A new peptidoleukotriene immunoaffinity resin was utilized for urinary LTE4 purification in a method that is easy and inexpensive, utilizing commercially available reagents. This method is described and compared to other methods. LTE4 (50-250 pg/mL) added to a urine extract was quantitatively recovered using the immunoaffinity resin. Similarly, LTE4 (50-400 pg/mL) added to urine was recovered between 63 and 76%. The coefficient of variation of samples purified and quantified on the same or on different days ranged from 8-10%. There was a strong correlation (r2 = 0.95) between LTE4 concentrations determined after immunofiltration and immunoaffinity purification. Although there was a good correlation between urinary LTE4 levels measured without purification compared to after immunoaffinity purification, the high y-intercept of 179 indicates the presence of interfering substances in unpurified urine. Urinary LTE4 in normal healthy adults was 80 +/- 7 pg/mg creatinine, similar to that previously reported following HPLC or immunofiltration purification. Urinary LTE4 was also measured in healthy children (age 3-12) and found to be 103 +/- 9.

The significance of variations in the angular correction factor in in situ gamma spectrometry

In situ gamma spectrometry is a powerful method of assessing radioactive contamination in soil. The most widely adopted calibration methodology relates the overall sensitivity of the detector system to the product of three calibration factors: (a) the flux at the detector per unit activity in the ground phi/S(A), (b) the detected count-rate per unit flux incident normally at the detector N0/phi and (c) a correction factor to take into account the angular non-uniformity in response of the detector (Nf/N0). The dependence of the latter factor on the activity distribution with soil depth is generally neglected despite the lack of published evidence to support this. By (i) modelling and (ii) use of published experimental profiles, this work examines the range of Nf/N0 values likely to be encountered in the field. It was found that the use of a fixed angular correction factor is justified given that the maximum errors in the derived activity concentration do not exceed 5% and are far outweighed by other uncertainties.

The choice of jet nebulizer, nebulizing flow, and addition of albuterol affects the output of tobramycin aerosols

The use of inhaled antibiotics in the treatment of cystic fibrosis has become widespread despite controversy in the literature as to the appropriate dosing regimen and its effectiveness. This study compared two tobramycin (T) preparations (one with and one without the addition of albuterol) using two different jet nebulizers in order to determine if drug output would be affected. Using calibrated flows from a dry compressed gas source of 6 and 8 L/min as well as a specific compressor (Pulmo-Aide), the Hudson 1720 nebulizer was compared with the newer disposable Hudson 1730. The albuterol preparation used in this study was the Ventolin (albuterol) Respirator Solution (VRS). The nebulizers were charged with (1) 2 mL T (80 mg/2 mL) with 0.5 mL VRS (5 mg/mL) and normal saline solution to make the total nebulizer charge of 3 or 4 mL, or (2) 2 mL T and either 1 or 2 mL normal saline solution. A laser diffraction analyzer (Malvern 2600) was used to determine the aerosol particle size distribution. From the distribution, the respirable fraction, which is the fraction of aerosol that could enter and remain in the lungs, was calculated. For all solutions and each particular flow, the Hudson 1730 had a larger respirable fraction of T. The addition of VRS lowered the surface tension of the solution in the nebulizer and resulted in a greater output of T. This effect was most apparent for the 3-mL volume fills of the Hudson 1720. The greatest differences were between the 3-mL nebulizer charges of T using the Hudson 1720 driven by a flow of 6 L/min, which produced 8 mg of T in the respirable fraction, compared with 35 mg produced by the Hudson 1730 driven by a flow of 8 L/min. These results suggest that different nebulizers, different nebulizer solutions, and different techniques of nebulization may result in very different amounts of T aerosol output in the respirable fraction.

Enhanced LTP in mice deficient in the AMPA receptor GluR2

AMPA receptors (AMPARs) are not thought to be involved in the induction of long-term potentiation (LTP), but may be involved in its expression via second messenger pathways. However, one subunit of the AMPARs, GluR2, is also known to control Ca2+ influx. To test whether GluR2 plays any role in the induction of LTP, we generated mice that lacked this subunit. In GluR2 mutants, LTP in the CA1 region of hippocampal slices was markedly enhanced (2-fold) and nonsaturating, whereas neuronal excitability and paired-pulse facilitation were normal. The 9-fold increase in Ca2+ permeability, in response to kainate application, suggests one possible mechanism for enhanced LTP. Mutant mice exhibited increased mortality, and those surviving showed reduced exploration and impaired motor coordination. These results suggest an important role for GluR2 in regulating synaptic plasticity and behavior.

Evaluation of surfactant treatment strategies after prolonged graft storage in lung transplantation

We have previously documented alterations in endogenous surfactant after lung transplantation and improved graft function in some dogs after instillation of bovine lipid extract surfactant (bLES) into the recipient. To determine the effect of bLES delivery method and timing of treatment on physiologic response and surfactant recovery, 21 canine left lung grafts were divided into four groups: (1) Treatment of the donor for 3 h with aerosolized bLES prior to graft storage (Donor Aerosol); (2) Treatment of the recipient with instilled bLES immediately after transplantation (Recipient Instilled); (3) No bLES treatment (Control); and (4) Aerosolized bLES in donors and instilled bLES in recipients (Combined Therapy). Aerosolized bLES was labeled with [3H]-dipalmitoylphosphatidylcholine (DPPC) and instilled bLES with [14C]-DPPC. Grafts were stored for 36 h, transplanted and reperfused for 6 h. The native right and transplanted left lungs were then lavaged and protein yield, surfactant aggregates, and bLES recovery were measured. After 6 h of reperfusion, PO2/FlO2 ratio was significantly better after Combined Therapy (372 +/- 52 mm Hg) than in the Recipient Instilled (117 +/- 47 mm Hg) and Control groups (87 +/- 26 mm Hg), with intermediate values in Donor Aerosol dogs (232 +/- 64 mm Hg). The recovery of donor aerosolized bLES from transplanted lungs was increased in dogs given Combined Therapy versus Donor Aerosol treatment alone (p = 0.03). Furthermore, with Combined Therapy there was an increased percentage of instilled bLES recovered from transplanted lungs compared with the Recipient Instilled group. We conclude that surfactant treatment strategies influence physiologic response and bLES recovery after prolonged lung preservation. Treatment of lung donors with exogenous surfactant prior to graft storage was associated with less severe lung injury. Combined donor and recipient bLES therapy resulted in a superior physiologic response during reperfusion in this model.

Learning opportunities for internal medicine residents: comparison of a tertiary care setting and a regional setting

PURPOSE

To compare the learning opportunities for internal medicine residents in tertiary care and community hospital settings.

METHOD

Two sites were studied: Victoria General Hospital, a teaching hospital affiliated with the Dalhousie University Faculty of Medicine, staffed by five general internists and serving Halifax County (population of 420,000); and South Shore Regional Hospital, serving the community of Bridgewater (with a catchment area of 50,000) and staffed by three general internists. All in- and outpatients seen in the two settings over a one-year period (1993) were described in accordance with the Canadian Institute for Health Information's major clinical categories, as well as a case mixture recommended as providing appropriate learning experiences for internal medicine clerks. Over a one-month period (August 1993), consecutive patients were interviewed, completing a health status questionnaire, the Medical Outcome Study Short Form 36 (SF-36).

RESULTS

Data were collected from the records of 2,763 patients, and the SF-36 questionnaire was administered to 406 patients. The data indicate that the settings were relatively similar except that there was more case variety in the tertiary care setting, and that more patients with cardiovascular disease and no patient with acquired immune deficiency syndrome were seen in the regional setting. Quality-of-life scores showed similarities to norms in the United States and United Kingdom, except that the ambulatory patients in the regional setting had rather lower scores.

CONCLUSION

Overall, the patients' problems in the regional and tertiary care settings offered similar learning opportunities.

The composition of glyphosate-tolerant soybean seeds is equivalent to that of conventional soybeans

One important aspect of the safety assessment of genetically engineered crops destined for food and feed uses is the characterization of the consumed portion of the crop. One crop currently under development, glyphosate-tolerant soybeans (GTS), was modified by the addition of a glyphosate-tolerance gene to a commercial soybean cultivar. The composition of seeds and selected processing fractions from two GTS lines, designated 40-3-2 and 61-67-1, was compared with that of the parental soybean cultivar, A5403. Nutrients measured in the soybean seeds included macronutrients by proximate analyses (protein, fat, fiber, ash, carbohydrates), amino acids and fatty acids. Antinutrients measured in either the seed or toasted meal were trypsin inhibitor, lectins, isoflavones, stachyose, raffinose and phytate. Proximate analyses were also performed on batches of defatted toasted meal, defatted nontoasted meal, protein isolate, and protein concentrate prepared from GTS and control soybean seeds. In addition, refined, bleached, deodorized oil was made, along with crude soybean lecithin, from GTS and control soybeans. The analytical results demonstrated the GTS lines are equivalent to the parental, conventional soybean cultivar.

The incidence of hyperemesis gravidarum is increased among Pacific Islanders living in Wellington

AIMS

To compare the incidence of hyperemesis gravidarum among Pacific Islanders living in Wellington with nonPacific Islanders and to investigate some properties of the disorder.

METHODS

Data were collected on all first time admissions to Wellington Women's Hospital for hyperemesis gravidarum over a 5-year period. Women were classified as having severe hyperemesis gravidarum if abnormalities of serum electrolytes and liver function tests results were present and as less severe if these abnormalities were absent. Almost all women had ketonuria. Mantel-Haenszel odds ratios, chi 2 analysis and Fisher's 2-tailed exact test were used for statistical analysis.

RESULTS

The proportion of hyperemesis gravidarum patients who were Pacific Islanders was significantly increased when compared to their proportion in a control group (p < 0.01). The difference remained significant when the hyperemesis patients were divided into less and more severe. Abnormal thyroid function test results were more common among Pacific Island patients than among nonPacific Island patients. This difference was significant (p < 0.01) only in the less severe group.

CONCLUSION

The incidence of hyperemesis gravidarum is significantly increased among Pacific Island women (especially Samoans) living in Wellington and is often associated with abnormalities of thyroid function test results.

Imaging strategies in the first 12 months after reduction of developmental dislocation of the hip

We have reviewed the records of 32 infants whose developmental dislocation of the hip (DDH) was treated by reduction and immobilization in a plaster cast. We examined 50 CT scans from 22 patients. The postreduction radiological studies led to a change of cast in 10 patients and, in five of them, the subluxation shown on CT scan was not seen in an earlier radiograph. Where reduction has been undertaken at the time of arthrography or in an older child, a plain radiograph may be adequate to confirm the position in the cast. In an infant, CT scans give superior information, have acceptable risks, and should be used in association with radiation protection measures.

The oral examination: a study of academic and non-academic factors

The oral examination in psychiatry for final-year medical students at Wellington and Dunedin School of Medicine, University of Otago, was studied. Between December 1989 and April 1990, 40 medical students were videorecorded during such an examination. The transcripts of the recording of each oral, and at a later date the videorecordings, were individually scored by a panel of six research psychiatrists who were experienced examiners. In addition verbal and non-verbal behaviour was rated using visual analogue scales and the students completed personality and anxiety questionnaires. There was a low level of agreement between research psychiatrists in the allocation of oral marks. The oral score was positively associated with the level of confidence of the student and negatively with anxiety in men.

Mouse alveolar surfactant: characterization of subtypes prepared by differential centrifugation

To characterize the properties of alveolar surfactant subfractions obtained from mouse lung by differential centrifugation, lavage fluid, following a preliminary centrifugation at 140 x g for 5 min to yield a cellular pellet (Pc), was sequentially centrifuged at 10,000 x g for 30 min, 60,000 x g for 60 min and 100,000 x g for 15 h; and the resultant pellets, respectively referred to as P10, P60 and P100, were harvested for electron microscopy, phospholipid analysis and surface tension measurements. Ultrastructural differences were observed, in that P10 contained large multilamellated structures which were typical of newly secreted surfactant, P100 contained small unilamellar vesicular structures, typical of catabolic end products of alveolar surfactant and P60 appeared to contain a mixture of structures present in P10 and P100 in addition to numerous, large unilamellar vesicles which were not present in either P10 or P100. Slight but significant differences were found in the phospholipid compositions of the three subfractions but not in the fatty acid composition of their phosphatidylcholine (PC) component. There were no significant differences in their disaturated PC/total PC ratios, but significant differences in their phospholipid/protein ratios. P60 had the highest proportion of phospholipid to protein. P10 and P60 demonstrated surface activity but P100 did not. Total alveolar surfactant phospholipid was evenly distributed among the three fractions. This pattern of distribution was significantly different from that observed in rabbit subfractions prepared by the same procedure. These data indicate that mouse alveolar surfactant consists of three distinct subfractions or subtypes which can be separately and quantitatively isolated by differential centrifugation.(ABSTRACT TRUNCATED AT 250 WORDS)

RTs performing venipuncture: a survey of state regulations

Venipuncture is an Essential component for nuclear medicine technologists and is expected to become an Essential for radiographers. A descriptive survey of radiation safety offices in the 50 states and the District of Columbia was conducted to determine which states license or certify nuclear medicine technologists, radiographers and/or radiation therapists and to identify specific statutory terminology relative to drug administration or venipuncture. Results showed only six states specifically addressed the issue of drug administration or venipuncture for radiographers and radiation therapists. With so few states addressing this issue, the question arises whether technologists who perform venipuncture or administer drugs are protected against litigation for performance of these procedures.

Lack of correlation between interspecific divergence and intraspecific polymorphism at the suppressor of forked region in Drosophila melanogaster and Drosophila simulans

Levels of DNA sequence polymorphism at the suppressor of forked [su(f)] region in natural populations of Drosophila melanogaster and Drosophila simulans are estimated by restriction map analysis. su(f) is located at the base of the euchromatic portion of the X chromosome where the level of crossing-over per physical length is extremely low. In a survey of 55 alleles from three natural populations of D. melanogaster, only 2 restriction sites of 27 hexanucleotide and 108 tetranucleotide restriction sites scored are polymorphic. Among 103 alleles from three natural populations of D. simulans, just one polymorphic restriction site is found in 109 tetranucleotide-recognizing restriction sites scored. The few polymorphisms in these surveys yield estimates of per site heterozygosities (0.00, 0.0002, and 0.0005, respectively) at least a factor of 10 less than the average observed at loci located in regions of the genome with normal levels of crossing-over. Because under a broad category of models of molecular evolution (including the neutral theory) a correlation between levels of polymorphism and interspecific divergence is expected, the DNA sequence divergence is examined for the su(f) region. Contrary to the predicted correlation, the estimated divergence (0.12 substitution per silent site) is, in fact, greater than that observed at loci in regions of normal crossing-over. According to an alternative hypothesis (hitchhiking effect model) intraspecific polymorphism is swept out of the population in regions of the genome closely linked to rare but selectively favored variants as they quickly go to fixation; the rate of divergence is, however, unaffected by these rare hitchhiking events. Thus, the observed paucity of polymorphism and lack of correlation with divergence are in accord with the theory of the hitchhiking effect and several recent reports of polymorphism and divergence in other genomic regions with reduced crossing-over per physical length.

A very unusual breast lump

A 77 year old woman presenting with a malignant phyllodes tumour of of the right breast with exclusively stromal metastases to axillary lymph nodes refractory to both radiotherapy and chemotherapy.

Molecular cloning and expression of ptxA, the gene encoding the 120-kilodalton cytotoxin of Actinobacillus pleuropneumoniae serotype 2

The genetic determinants of the 120-kDa cytotoxin of Actinobacillus pleuropneumoniae serotype 2 were isolated from a lambda DNA library by a plaque immunoblot technique. Expression of the 120-kDa polypeptide was confirmed by Western immunoblot analysis of infected Escherichia coli cell lysates, which were shown to be toxic for porcine alveolar macrophages in vitro. The genetic determinants of the toxin were subcloned into the plasmid vector pUC18. This plasmid (pPTX1) directed the synthesis and secretion of the active 120-kDa cytotoxin in E. coli. The recombinant toxin was indistinguishable from native cytotoxin from A. pleuropneumoniae serotype 2 with respect to molecular size, reaction in Western blot analysis, heat lability, cytotoxic activity, and neutralization by serum antibody. A restriction endonuclease cleavage map of pPTX1 was prepared, and deletion mutants were used to locate the minimal region of DNA required for production of intracellular toxin; this gene was termed ptxA. Southern hybridization analysis with a 1.7-kb PvuII fragment located within the ptxA gene revealed sequences with a high degree of homology in serotype reference strains 2, 3, 4, 6, and 8. Other reference strains did not contain sequences that were recognized by this probe. However, related sequences (greater than 71% homology) were detected in Actinobacillus actinomycetemcomitans and A. equuli. Weak hybridization was observed between the ptxA probe and pLKT5, which carries the lktAC genes of Pasteurella haemolytica, and between the ptxA probe and pAPH1, which carries the structural gene for type II hemolysin from A. pleuropneumoniae. The isolation of the genetic determinants of this cytotoxin will enable investigations of the structure and organization of the ptx DNA region and further analysis of its role in the pathogenesis of pleuropneumonia.

An investigation of bacterial causes of arthritis in slaughter hogs

Joints from 153 arthritic and 80 normal slaughter hogs were examined by culture for presence of bacteria. Although none of the normal joints yielded bacteria, 37% of the disease joints were positive for bacterial growth. Of 67 bacterial isolates obtained, 45% were Erysipelothrix rhusiopathiae. Occurrence of other bacteria in order of their frequency was Streptococcus suis (16%), Actinomyces pyogenes (10%), Mycoplasma spp. including 3 M. hyorhinis isolates (7%), staphylococci (7%), Streptococcus spp. (6%), and organisms of uncertain significance (7%).

The history of ventriculoscopy: where do we go from here?

With the availability of better endoscopes, improved lighting and increased instrumentation, the use of ventriculoscopy and ventriculostomy in the management of hydrocephalus is becoming increasingly more common. Neurosurgeons recognized the potential for endoscopic surgery early in this century, but were frustrated in many of their attempts at treatment due to the poor quality of the instruments available. Nevertheless, much progress has been made, and the stage was set for better results with modern instrument design. This paper reviews the history of endoscopes in neurosurgery and ponders the direction these instruments will take us in the near future.

Projections of the tectospinal tract to the upper cervical spinal cord of the cat: a study with the anterograde tracer PHA-L

The goal of the present experiments was to re-examine the spinal projections of neurons in the superior colliculus (SC) of the cat by taking advantage of the high sensitivity of the anterograde tracer, phaseolus vulgaris leucoagglutinin (PHA-L). In seven experiments, multiple injections of PHA-L into different regions of the SC labelled a total of 172 axons in the predorsal bundle; yet only 11 tectospinal tract (TST) axons were found in the upper cervical spinal cord. Collaterals emerging from these axons were rare and arose exclusively from TST axons with a diameter of less than 1 micron. Individual collaterals had different termination zones: some terminated in the lateral part of lamina V and VI after taking a dorsolateral course through lamina VII and VIII; others terminated in the medial part of lamina VII. One collateral terminated within lamina IX and the ventral part of lamina VIII. The combined termination of all collaterals was densest in lamina VII and dorsal lamina VIII. A small number of boutons were also found in the lateral parts of laminae V and VI, and in lamina IX and immediately adjacent regions in lamina VIII. Compared to axons belonging to other spinal descending systems, individual TST axons give rise to much simpler intraspinal collaterals with relatively few boutons. This feature, together with the relative paucity of TST axons, suggests that direct connections from the SC to neurons in the upper cervical spinal cord are sparse. Furthermore, our results are consistent with electrophysiological studies that show that few, if any, neck motoneurons receive monosynaptic connections from TST neurons. Projections to neck motoneurons must therefore involve a relay, either through other descending pathways, such as the reticulospinal system, or via local segmental interneurons.

Characterization of prostate cancer, benign prostatic hyperplasia and normal prostates using transrectal 31phosphorus magnetic resonance spectroscopy: a preliminary report

We assessed the ability of 31phosphorus (31P) transrectal magnetic resonance spectroscopy to characterize normal human prostates as well as prostates with benign and malignant neoplasms. With a transrectal probe that we devised for surface coil spectroscopy we studied 15 individuals with normal (5), benign hyperplastic (4) and malignant (6) prostates. Digital rectal examination, transrectal ultrasonography and magnetic resonance imaging were used to aid in accurate positioning of the transrectal probe against the region of interest within the prostate. The major findings of the in vivo studies were that normal prostates had phosphocreatine-to-adenosine triphosphate (ATP) ratios of 1.2 +/- 0.2, phosphomonoester-to-beta-ATP ratios of 1.1 +/- 0.1 and phosphomonoester-to-phosphocreatine ratios of 0.9 +/- 0.1. Malignant prostates had phosphocreatine-to-beta-ATP ratios that were lower (0.7 +/- 0.1) than those of normal prostates (p less than 0.02) or prostates with benign hyperplasia (1.1 +/- 0.2, p less than 0.01). Malignant prostates had phosphomonoester-to-beta-ATP ratios (1.8 +/- 0.2) that were higher than that of normal prostates (p less than 0.02). Using the phosphomonoester-to-phosphocreatine ratio, it was possible to differentiate metabolically malignant (2.7 +/- 0.3) from normal prostates (p less than 0.001), with no overlap of individual ratios. The mean phosphomonoester-to-phosphocreatine ratio (1.5 +/- 0.5) of prostates with benign hyperplasia was midway between the normal and malignant ratios, and there was overlap between individual phosphomonoester-to-phosphocreatine ratios of benign prostatic hyperplasia glands with that of normal and malignant glands. To verify the in vivo results, we performed high resolution magnetic resonance spectroscopy on perchloric acid extracts of benign prostatic hyperplasia tissue obtained at operation and on a human prostatic cancer cell line DU145. The extract results confirmed the differences in metabolite ratios observed in vivo. We conclude that transrectal 31P magnetic resonance spectroscopy can characterize metabolic differences between the normal and malignant prostate.

Prospective evaluation of a totally implantable drug delivery system. Improved results at 4-year follow-up

Totally implantable drug delivery systems have facilitated chemotherapy in cancer patients. The incidence of complications has been acceptable but not optimal. A series of 140 consecutive implants over a 4-year period is presented. The total follow-up was 41,185 days. Reversible obstruction was present in 12.8% of portals. The infection-erosion rate was 4.2%; only 6.3% of patients required removal of the system because of failure. In the last 111 patients only one device failed (0.9%). The reasons for these improved results are analysed, and recommendations are made to improve the current management of these devices.

Control of embryonic motoneuron survival in vivo by ciliary neurotrophic factor

During development of the nervous system, neurons in many regions are overproduced by proliferation, after which the excess cells are eliminated by cell death. The survival of only a proportion of neurons during normal development is thought to be regulated by the limited availability of neurotrophic agents. One such putative trophic agent is ciliary neurotrophic factor (CNTF), a polypeptide that promotes the survival of ciliary, sensory, and sympathetic neurons in vitro. In contrast to the results of in vitro studies, however, the daily treatment of chick embryos in vivo with purified human recombinant CNTF failed to rescue any of these cell populations from cell death, whereas CNTF did promote the in vivo survival of spinal motoneurons. Thus, CNTF may not act as a neurotrophic agent in vivo for those embryonic neurons (especially ciliary neurons) on which it acts in vitro. Rather, CNTF may be required for in vivo survival of motoneurons.

Phase II study of pibenzimol in pancreatic cancer. A Southwest Oncology Group study

Twenty-three patients with advanced pancreatic adenocarcinoma were treated with Pibenzimol utilizing a daily intravenous schedule for five days. There were no objective responses seen. The major toxicity was pancreatic with grade 3 hyperglycemia in eleven patients. Pibenzimol is inactive in patients with advanced pancreatic adenocarcinoma.