Dose-response relationships in hepatic injury produced by alcohol and carbon tetrachloride

Dose-response relationships were examined for the production of hepatic fibrosis and cirrhosis by combined exposure of male Porton rats to alcohol and carbon tetrachloride. Alcohol was administered orally in Lieber-DeCarli liquid diet at levels of 75, 150, or 300 kcal/liter, giving mean daily intakes of 2.29, 4.61, and 8.16 g/kg/day, respectively. Carbon tetrachloride was administered by inhalation at concentrations of 10, 20, or 40 ppm, 6 hr/night, 5 nights/week. Liver biopsies were taken at intervals up to a maximum treatment period of 20 weeks. All four rats that received the high dose of both agents, and 1 of 4 that received the medium alcohol and high carbon tetrachloride treatments, were cirrhotic by 10 weeks. Two of the 4 rats that received the low alcohol and high carbon tetrachloride dose were cirrhotic at 20 weeks. Cirrhosis was not observed in rats that received the low or medium carbon tetrachloride dose, but some degree of hepatic fibrosis was observed in all treatment groups. Severity of fibrosis was significantly associated with both dose of alcohol and dose of carbon tetrachloride received. It is concluded that, in the alcohol-carbon tetrachloride rat model for chronic liver injury, both alcohol and carbon tetrachloride contribute to the response in a dose-related manner. Hepatic injury was observed even when relatively low doses of these agents are administered together.

Intraoperative measurement of Javid shunt flow with transit-time ultrasound

Transit-time ultrasound methods were used to measure blood flow in 37 patients undergoing carotid endarterectomy. Internal carotid flow before (ICFbef) and after (ICFaft) endarterectomy was measured with a 6 mm perivascular probe, and Javid shunt flow (SF) was measured with a clamp-on probe. For the entire group ICFbef averaged 117 +/- 67 ml/min and ICFaft was 173 +/- 67 ml/min. Shunt flow averaged 123 +/- 51 ml/min. The differences between ICFbef and ICFaft and between SF and ICFaft were significant (ANOVA, p < 0.01) but the difference between ICFbef and SF was not. The relationship between ICFbef and SF appeared to define two groups of patients. Those in whom SF was greater than ICFbef (SF > ICFbef) had more stenosis evident on preoperative arteriograms (64.7% +/- 14.55% maximum single diameter stenosis) and a greater average increase in ICF (151% +/- 159%) than those with SF < or = ICFbef (43.3% +/- 20.9% stenosis and 34% +/- 54% increase in ICF), suggesting that the relationship between SF and ICFbef defines groups with different hemodynamic responses. The similarity between SF and ICFbef indicates that Javid shunt flow offers adequate protection from cerebral ischemia. A practical benefit of the shunt clamp-on flow probe is the ability afforded to recognize shunt occlusions.

Changes in internal carotid blood flow after carotid endarterectomy correlate with preoperative stenosis

BACKGROUND

The relationship between preoperative stenosis and the effect of carotid endarterectomy (CEA) upon internal carotid blood flow (ICF) is not well understood. With the intention of better characterizing this, we compared intraoperative measurements of internal carotid blood with the maximum single diameter stenosis found in preoperative angiograms.

METHODS

Fifty-two patients undergoing 64 carotid endarterectomies (12 bilateral) had transit-time ultrasound perivascular probes used to measure ICF before and after CEA, and the percent change in ICF (% delta ICF) achieved was calculated. Maximum single-diameter stenosis was determined by comparing the least diameter in the flow path from the common carotid to the normal-appearing internal carotid just distal to bifurcation disease.

RESULTS

The entire group had a mean of 53 +/- 21% stenosis found on preoperative angiograms, and % delta ICF averaged 64 +/- 92%. When divided into subgroups based on degree of stenosis, patients with 0% to 40% stenosis (n = 17) had % delta ICF of 32 +/- 46%, patients with 41% to 70% stenosis (n = 30) had % delta ICF of 72 +/- 105%, and patients with more than 70% stenosis had % delta ICF of 168 +/- 160%. The differences in % delta IC were significant for the > 70% group compared with the other groups (analysis of variance, P < 0.005), and marginally significant (P = 0.056) between the 0% to 40% and the 41% to 70% groups. The scatter plot of % delta ICF versus stenosis showed a significant second order direct correlation (r = 0.428, P < 0.001) and disproportionate increases in ICF above 60% stenosis.

CONCLUSION

A curvilinear relationship between stenosis and immediate increase in ICF after CEA was demonstrated in agreement with theory, and in those patients with more than approximately 60% single-diameter stenosis, large disproportionate increases in blood flow were more frequently observed.

Microbial transformations of steroids--VIII. Transformation of progesterone by whole cells and microsomes of Aspergillus fumigatus

The filamentous fungus, Aspergillus fumigatus, efficiently hydroxylated exogenous progesterone producing, after 3 h of incubation, 11 alpha- and 15 beta-hydroxyprogesterone as major products, 7 beta-hydroxyprogesterone as a minor product and trace amounts of 7 beta, 15 beta- and 11 alpha, 15 beta-dihydroxyprogesterone. After 72 h the dihydroxyprogesterones were the sole metabolites in the culture medium. Microsomes, prepared by Ca2+ precipitation, catalysed only monohydroxylation of progesterone at the same sites as whole cells. Hydroxylation was dependent on NADPH (but not NADH) which was replaceable by NaIO4. Hydroxylation was inhibited by carbon monoxide and by the azole fungicide, ketoconazole. Microsomes gave a dithionite-reduced, carbon monoxide difference absorbance spectrum with a peak at 448 nm and a Type-I progesterone-binding spectrum typical of cytochrome P450 interaction with substrate. Ketoconazole inhibition studies suggest the presence of two non-inducible cytochrome P450 progesterone hydroxylases, one possessing 7 beta site-selectivity, the other 11 alpha/15 beta site-selectivity.

The pathology of liver injury induced by the chronic administration of alcohol and 'low-dose' carbon tetrachloride in Porton rats

We have previously established a model for micronodular cirrhosis by feeding Wistar rats alcohol, in the Lieber-DeCarli liquid diet, and exposing them to 'low-dose' carbon tetrachloride (CCl4) vapour for 10 weeks. This study reports the spectrum of liver pathology seen in male Porton rats exposed to 'low-dose' CCl4 vapour 5 nights/week, 6 h/night while being fed alcohol (300 kcal/L) in the Lieber-DeCarli diet. Micronodular cirrhosis developed in all animals after 5-7 weeks of treatment. The simultaneous administration of silymarin, a putative hepatoprotective agent, in the liquid diet, did not alleviate or prevent the chronic liver injury. The histopathological features of the liver injury are described, with particular emphasis on the presence of small epithelial cells ('progenitor or stem cell'), which appear to be playing a role in liver regeneration.

Covalent immobilization of protein monolayers for biosensor applications

Various sensor technologies require a monolayer of tightly bound proteins. Five methods for protein immobilization were evaluated, comprising two methods of linker attachment to a silicon nitride surface (CNBr, silanization) and three methods of linker attachment to the protein (via primary amines, carboxyl groups, and the aromatic rings of tyrosine and histidine). These covalent binding methods were evaluated by immobilization of the enzyme alkaline phosphatase and with monoclonal antibodies tagged with 125I. It was determined that approximately 75% of the protein on the "covalently" immobilized samples was simply adsorbed. Adsorption was reduced by varying the pH and ionic strength of the wash buffers as well as by adding chaotropes and competitors to the wash buffer. A more efficient method of reducing adsorption was to perform the immobilization in the presence of a detergent; 0.5% Tween 60 was the most effective detergent studied. The optimized procedure gives a surface loading of 1.20 x 10(12) MAb/cm2. of which approximately 10% was adsorbed protein. This surface density is consistent with a monolayer of immobilized protein. This protein was shown to be active by challenging immobilized antibodies with 35S-labelled antigen; only the antibody/antigen pair released radioactive material upon elution.

Impact of endoscopic therapy on outcome of operation for bleeding peptic ulcers

Since elective surgery for bleeding peptic ulcer disease has declined, the surgical opinion is that patients who undergo emergency operation have more advanced disease and possibly a poorer outcome. We examined current mortality for surgical correction of upper gastrointestinal (UGI) bleeding from peptic ulcer disease. Between July 1, 1986, and December 31, 1990, 1,213 patients had esophagogastroduodenoscopy for UGI bleeding (659 with peptic ulcer disease, 219 with gastroesophageal varices, 152 with esophagitis, 83 with other causes, and 100 with no source found). Of 110 patients with peptic ulcer disease treated by endoscopic methods, bleeding was controlled in 90, and 20 required operation for failed endoscopic control. Another 22 patients had primary operation for exigent bleeding with diagnostic endoscopy only. The overall results in our series compared favorably with two pre-therapeutic endoscopy index series (Nottingham, 1982; University of Pittsburgh, 1982). Our operation rate was 6%, with a mortality rate of 7%, compared with operation rates of 15% to 27%, with mortality rates of 21% to 22% in the historical control series. In conclusion, we found that: (1) endoscopic control of UGI bleeding from peptic ulcer disease has decreased the incidence of operation compared with historical series; (2) overall operative mortality is decreasing; and (3) the major postoperative complication is rebleeding.

Isolation of infectious laryngotracheitis virus from proximal femora of lame broiler chickens

Two herpesviruses previously isolated from seven of 19 affected joint/bone samples in an earlier survey of lameness in broilers were identified. They were characterised as infectious laryngotracheitis (ILT) virus using serum neutralisation, immunofluorescence, restriction enzyme analysis and polymerase chain reaction techniques. In experimentally infected chicks, one of the isolates caused mild ILT and intranuclear inclusion bodies were present in the tracheal epithelium after four days. It is considered unlikely that these viruses were involved in the pathological changes in the affected legs. The possibility that ILT pathogenesis and epidemiology are more complex than currently understood is discussed.

Tsp45I, a new thermostable site-specific endonuclease that cleaves the recognition sequence 5'-decreases GTSAC-3'

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A new restriction endonuclease, TspEI, from the genus Thermus that generates cohesive termini compatible with those of EcoRI

The detection, isolation and properties of the restriction endonuclease TspEI are described. The canonical recognition sequence (AATT) is the same as the 4-bp core of the 6-bp sequence (GAATTC) of EcoRI. Hydrolysis occurs 5' to the palindromic tetramer so that TspEI produces the same cohesive termini as EcoRI. TspEI therefore has an obvious application in producing partial digests of DNA for ligation to EcoRI-digested cloning vectors.

Evaluation of access to care and medical and behavioral outcomes in a school-based intervention program for attention-deficit hyperactivity disorder

The Project for Attention-Related Disorders (PARD), instituted by the San Diego (Calif.) School District. represents a unique approach to identification, referral, and management of children with Attention-Deficit Hyperactivity Disorder. As a school-based program, PARD coordinates medical, psychosocial, behavioral, and educational interventions for each child, and provides resources for school personnel caring for children with ADHD. Three years after instituting PARD, about 60% to 70% of the children showed improvement after enrollment, evaluation, and treatment. Parental involvement in and acceptance of intervention for their children represented a significant follow-up problem. Both medical and nonmedical interventions such as counseling, special programs, and behavior modification helped improve the educational life of these children.

Can histopathologists reliably diagnose molar pregnancy?

AIMS

To assess the degree of difficulty in diagnosing partial mole by analysing intraobserver and interobserver agreement among a group of pathologists for these diagnoses.

METHODS

Fifty mixed cases of partial mole, complete mole, and non-molar pregnancy were submitted to seven histopathologists, two of whom are expert gynaecological pathologists; the other five were district general hospital consultants, one of whom works in Australia. These participants gave each slide a firm diagnosis of either partial mole, complete mole, or non-molar pregnancy. Some 12 months later, the slides were recorded and again submitted for a second diagnostic round to assess intraobserver as well as interobserver agreement. Standard histological criteria for each diagnostic category were circulated with the slides.

RESULTS

kappa statistics showed that complete mole could be reliably distinguished from non-molar pregnancy, but neither non-molar pregnancy nor complete mole could be easily differentiated from partial mole. In only 35 out of 50 cases was there agreement between five or more of the seven participants. Agreement between the expert gynaecological pathologists was no better than for others in the group. Interestingly, the intraobserver agreement for each pathologist was good to excellent.

CONCLUSIONS

These results imply that the reported histological criteria are either not being applied consistently or that they are lacking in practical use. An atypical growth pattern of trophoblast, rather than the polar accentuation seen in normal first trimester pregnancies, seems to be the important diagnostic histological feature for partial mole. Ploidy studies might also help with problem cases.

Discovering work excitement among navy nurses

An interest in what makes work exciting among Navy Nurse Corps officers led to the use of Simms' work excitement data collection protocol in Navy Medical Centers. Significant levels of work excitement were found among Navy nurses when compared to civilian nurses in non-military settings. Overall, results indicated that Navy nurses are excited about the variety, the leadership/management experiences, and the opportunities for teaching and learning--elements that are the very essence of Navy nursing practice.

Malignant potential of aneuploid pancreatic endocrine tumours

Evaluation of the malignant potential of pancreatic endocrine tumours is difficult by histological criteria alone. Nuclear deoxyribonucleic acid (DNA) cytometric analysis can provide significant prognostic and biological information in a number of solid human tumours. Thus, the DNA profiles and nuclear parameters of 39 patients with pancreatic endocrine tumours diagnosed from 1969 to 1989 were studied, using computerized video image analysis. Of the 39 patients with tumours, 27 cases did not have evidence of metastatic disease at the time of investigation. The majority of these (N = 21) showed a diploid profile. Five were aneuploid and one was tetraploid. In the 12 tumours that proved malignant, three had tissue of both primary tumour and the metastases analysed; six had material only from the primary tumour, although metastatic disease was established clinically; and another three only had tissue from the secondary tumour studied. The majority of the malignant cases were aneuploid (N = 7); three were diploid; one showed a diploid primary but an aneuploid secondary, and one showed a hyperdiploid pattern. The percentage of nuclei with a DNA content greater than 5N (5CER) did not seem to contribute further to the assessment nor did the means of the nuclear areas and shape factors. It appears that ploidy studies may be useful in predicting malignant potential of pancreatic endocrine tumours. There is a high rate of immunostaining for insulin by benign pancreatic endocrine tumours and this may be a useful adjunct to distinguish them from their malignant counterparts. However, there is no statistically significant correlation between the expression of various hormones and the DNA ploidy of tumour cells.

Straight segmental versus bifurcation grafts for repair of abdominal aortic aneurysm

The decision of two surgical teams to repair an infrarenal aneurysm with a straight or bifurcation graft in 94 patients was investigated. Nine patients had an emergency operation and the two who died within 30 days of surgery (mortality rate 2%) had a ruptured aneurysm. Of 88 patients with follow-up data of at least 1 year (mean 3.5 years), 46 received bifurcation grafts and 42 tube grafts. The mean transverse diameter of the aneurysm on ultrasonography was 6.5 cm for straight and 6.1 cm for bifurcation grafts. The mean duration of operation was longer for bifurcation than straight grafts (4.2 versus 3.3 h, P < 0.05) and intraoperative blood loss greater for the former (2292 versus 1350 ml, P < 0.05). The incidences of late complications for the two grafts were not different. The only secondary aneurysm repair was a staged procedure on a descending thoracic aortic aneurysm. No postoperative iliac aneurysms were detected by routine physical examination and pelvic ultrasonography in patients receiving straight grafts. Even though there was no preselection of patients by disease status, one surgical team relying on preoperative arteriography successfully replaced 28 of 39 aneurysms (72%) with tube grafts while the other team using primarily intraoperative assessment placed straight grafts in only 14 of 49 patients (29%). In conclusion, straight grafts can be implanted in approximately two-thirds of patients undergoing aortic aneurysm repair with significantly less operating time and blood loss and without increase in the incidence of late iliac occlusion or dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Subcapsular hematoma as a predictor of delayed splenic rupture

Over the past 46 months at a level I trauma center, 966 computed tomography (CT) scans were performed for blunt abdominal trauma. Eighty-three (8.6%) demonstrated splenic injury, and 31 (3.2%) of these showed a subcapsular hematoma with or without associated parenchymal damage. Of the 31 patients, 23 were managed conservatively, based initially upon surgeons' preference (14 patients) and after March 1990 to conform to the authors' splenic trauma protocol (nine patients). The eight patients operated upon were hemodynamically stable and all underwent splenectomy. Subcapsular hematoma, as diagnosed by preoperative CT scan, was confirmed in each of the eight celiotomies. Parenchymal involvement, which had also been identified in these eight patients by CT, was evident at operation in all, and hilar involvement occurred in three. None of the 23 observed patients developed delayed splenic rupture. All were discharged home with outpatient follow-up in surgical clinic to at least 1 month without further complication. The authors came to the following conclusions: 1) Subcapsular hematoma is neither a predictor for delayed splenic rupture, nor by itself an indication for operative management of the injured spleen in the hemodynamically stable patient; 2) Degree of parenchymal injury based on CT morphology, specifically hilar involvement, signifies the need for laparotomy with splenectomy; 3) Splenorrhaphy has a reduced role in splenic trauma because most injuries now operated upon are severe.

Demonstration of sites of latency of infectious laryngotracheitis virus using the polymerase chain reaction

Mature laying chickens were inoculated intratracheally with a field strain of infectious laryngotracheitis (ILT) virus. Tracheal swabs were collected regularly from all birds for virus culture. At various times post-inoculation, pairs of birds were killed and tissues removed for detection of virus products using conventional tissue homogenization and culture, organ culture, indirect immunofluorescence (IF) and also the polymerase chain reaction (PCR). The latter was used to detect a DNA sequence from the ILT virus thymidine kinase gene. Following inoculation the birds developed mild respiratory disease with clinical signs characteristic of ILT from 3 to 10 days post-inoculation. Trachea and turbinate tissues were virus-positive as determined by virus isolation, organ culture, IF and PCR on day 4 post-inoculation. After recovery from the acute phase, virus shedding initially ceased, then intermittent, low level shedding was recorded for five of the six remaining birds. In an attempt to locate sites of latency, pairs of birds were sampled at 31, 46 and 61 days post-inoculation. Virus was not detected in upper respiratory tract or ocular tissues by conventional techniques, or in the trigeminal, proximal and distal ganglia. All tissues were also negative by PCR, except for the trigeminal ganglia of five of the six birds. All PCR-positive birds had previously shed ILT virus intermittently between days 19 and 59 post-inoculation. As we did not detect viral DNA in any of the other tissues sampled from clinically recovered birds, we conclude that the trigeminal ganglion is the main site of latency of ILT virus.

Guidelines for surgical residents' working hours. Intent vs reality

To comply with voluntary California medical school guidelines, our general surgery residency program reduced in-house call to 1 in 4 nights, and scheduled a 72-hour work-week. We assessed the effectiveness of these changes by prospectively surveying the actual working hours of surgical house staff through completion of a daily schedule for 1 month. Actual in-hospital hours averaged 98 per week, significantly exceeding the scheduled hours, and were greater for interns (100 hours) and junior residents (97 hours) than for chief residents (95 hours). Twenty hours (22%) of nonconference waking hours were spent on so-called scut work. Significant reduction of intern work hours could be accomplished by expansion of ancillary care, allowing more time for direct patient care. The effect on senior house staff hours would be less dramatic but might be sufficient to bring hours into compliance with proposed limits.