Local delivery of vascular endothelial growth factor accelerates reendothelialization and attenuates intimal hyperplasia in balloon-injured rat carotid artery

BACKGROUND

Most strategies designed to reduce restenosis by the use of pharmacological or biological reagents involve direct inhibition of vascular smooth muscle cell (SMC) proliferation. Alternatively, SMC proliferation might be indirectly inhibited if reendothelialization could be specifically facilitated at sites of balloon-induced arterial injury. Accordingly, we investigated the hypothesis that application of an endothelial cell (EC)-specific mitogen to a freshly denuded intimal surface could accelerate reendothelialization and thereby attenuate intimal hyperplasia.

METHODS AND RESULTS

The left carotid artery of 31 Sprague-Dawley rats was subjected to balloon injury, after which 16 rats were treated with a 30-minute incubation with 100 micrograms of vascular endothelial growth factor (VEGF), an EC-specific mitogen. Control animals (n = 15) received a 30-minute incubation with 0.9% saline. At 2 weeks after balloon injury, carotid artery reendothelialization was markedly superior in the VEGF-treated group compared with the control group (14.59 +/- 1.12 versus 7.96 +/- 0.51 mm2, P < 0.005). The extent of reendothelialization measured at 4 weeks after balloon injury remained superior for arteries treated with VEGF (18.04 +/- 0.90 mm2) versus saline (13.42 +/- 0.84 mm2, P < .005). Neointimal thickening was correspondingly attenuated to a statistically significant degree in arteries treated with VEGF versus the control group at both the 2-week and 4-week time points. Immunostaining for proliferating cell nuclear antigen (PCNA) disclosed a threefold increase in PCNA-positive cells in the neointima of control arteries versus VEGF-treated arteries at 2 weeks after injury.

CONCLUSIONS

Application of VEGF, an EC-specific growth regulatory molecule, may be effectively used in vivo to promote reendothelialization and thereby indirectly attenuate neointimal thickening due to SMC proliferation.

Apoptosis in human atherosclerosis and restenosis

BACKGROUND

Apoptosis has been recognized in normal, including rapidly proliferating, cell populations and is inferred to be potentially responsible for the maintenance of stable cell numbers in tissues with various degrees of proliferative activity. Previous studies performed in rats indicated that despite the persistence of a relatively high level of injury-induced proliferative activity, total arterial smooth muscle content at 12 weeks remained unchanged from that measured at 2 weeks, suggesting that accrual of vascular smooth muscle cells is mitigated by cell death. The extent to which apoptosis may be observed in human atherosclerosis and/or restenosis, however, has not been previously established.

METHODS AND RESULTS

We performed immunohistochemical studies on 56 specimens retrieved from patients undergoing directional atherectomy for primary atherosclerotic lesions or recurrent arterial narrowing after percutaneous revascularization (restenosis). Immunohistochemical staining disclosed evidence of apoptosis in 35 (63%) of the 56 specimens studied. When present, immunohistochemical evidence of apoptosis was typically limited to < 2% of cells in the specimen. The finding of apoptosis, however, was not distributed equally among four groups of specimens studied. Specimens retrieved from patients with restenosis were more frequently observed to contain foci of apoptosis than specimens retrieved from patients with primary atherosclerotic lesions. Among 14 peripheral arterial specimens from patients with restenosis, 13 (93%) contained foci of apoptosis; in contrast, apoptosis was observed in only 6 (43%) of 14 peripheral specimens from patients with primary lesions (P = .0046). Among coronary arterial specimens, apoptosis was observed in 12 (86%) of 14 specimens from patients with restenosis versus 6 (29%) of 14 specimens from patients with primary obstructions (P < .0075).

CONCLUSIONS

Apoptosis is a feature of human vascular pathology, including restenotic lesions and, to a lesser extent, primary atherosclerotic lesions. The findings of the present study suggest that apoptosis may modulate the cellularity of lesions that produce human vascular obstruction, particularly those with evidence of more extensive proliferative activity.

Low-efficiency of percutaneous adenovirus-mediated arterial gene transfer in the atherosclerotic rabbit

Recombinant adenoviruses are the most efficient vectors with which to perform arterial gene transfer. Previous in vivo studies of adenovirus-mediated arterial transfection, however, have been performed using normal or endothelium-denuded arteries. It is unclear whether these results can be extended to atherosclerotic arteries. Accordingly, this study was designed to (a) assess the feasibility of adenovirus-mediated gene transfer to atherosclerotic lesions, and (b) compare the transfection efficiency, anatomic distribution of transfected cells, and duration of transgene expression achieved in normal versus atherosclerotic arteries. A recombinant adenovirus including a nuclear-targeted beta-galactosidase gene was percutaneously delivered to the iliac artery of normal (n = 25) and atherosclerotic (n = 25) rabbits. Transgene expression, assessed by morphometric as well as chemiluminescent analyses, was documented in all normal and atherosclerotic arteries between 3 and 14 d after gene transfer, but was undetectable at later time points. Transfected cells were identified as smooth muscle cells located in the media of normal arteries, and in the neointima and the vasa-vasora of atherosclerotic arteries. Two percent of medial cells, but only 0.2% of medial and neointimal cells expressed the transgene in normal and atherosclerotic arteries, respectively (P = 0.0001). Similarly, nuclear beta-galactosidase activity was higher in normal than in atherosclerotic arteries (3.2 vs. 0.8 mU/mg protein, P = 0.02). These findings indicate that atherosclerosis reduces the transfection efficiency which can be achieved with adenoviral vectors, and thus constitutes a potential limitation to adenovirus-based, arterial gene therapy.

Identification of 92-kD gelatinase in human coronary atherosclerotic lesions. Association of active enzyme synthesis with unstable angina

BACKGROUND

Acute coronary ischemia is usually initiated by rupture of atherosclerotic plaque, leading to intracoronary thrombosis and clinical sequelae. The proximate cause of plaque rupture is unknown. Accordingly, we investigated the potential role of the 92-kD gelatinase member of the matrix metalloproteinase family in acute coronary ischemia.

METHODS AND RESULTS

Coronary atherectomy specimens from patients with atherosclerosis and an acute ischemic syndrome consistent with recent plaque rupture (unstable angina) (n = 12) were immunostained for the presence of 92-kD gelatinase; the results were compared with those obtained by identical study of atherectomy specimens from patients with atherosclerosis and angina but without acute ischemia (stable angina) (n = 12). Positive immunostaining for 92-kD gelatinase was present in 83% of specimens from both unstable and stable angina patients. However, intracellular localization of enzyme (indicating active synthesis) was documented in 10 of 10 positively stained specimens from patients with unstable angina compared with 3 of 10 positively stained specimens from patients with stable angina. Macrophages and smooth muscle cells were the major sources of 92-kD gelatinase in all specimens examined by immunostaining of adjacent sections.

CONCLUSIONS

92-kD gelatinase is commonly expressed in coronary arterial atherosclerotic lesions. Active synthesis of 92-kD gelatinase by macrophages and smooth muscle cells in atherosclerotic lesions may play a pathogenic role in the development of acute coronary ischemia.

One-year follow-up in the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT I)

BACKGROUND

Directional atherectomy is a frequently used percutaneous revascularization strategy, but its long-term outcomes have not previously been compared with those of balloon angioplasty in a prospective trial.

METHODS AND RESULTS

The 1012 patients enrolled in the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT I) were followed for at least 1 year after randomization. Analyses of predetermined end points were performed, including a detailed analysis of the 14 patients who died. At 1 year, 11 patients had died in the atherectomy group compared with 3 in the angioplasty group (2.2% versus 0.6%, P = .035), with an excess of out-of-hospital deaths (2.2% versus 0.2%, P = .01) and late cardiac deaths (1.6% versus 0%, P = .01). Univariate predictors of death included age, abrupt closure, periprocedural enzyme elevation, and peripheral vascular complications. There was no evidence that the excess of deaths after atherectomy was linked to perforation, ectasia, or deep resection. Cumulative rates of myocardial infarction were higher in those who had been randomized to atherectomy than in those randomized to angioplasty (8.9% versus 4.4%, P = .005) with a trend toward excess Q-wave and non-Q-wave infarctions. By multivariate analysis, atherectomy was the only variable predictive of the combined end point of death or myocardial infarction. No clinical or angiographic characteristics added to this index. Rates of repeat percutaneous intervention at the target site (24.4% after atherectomy versus 25.9% after angioplasty), coronary artery bypass surgery (9.3% versus 9.1%), hospitalization (50% versus 47.1%), and stroke (1% in both groups) were not significantly different.

CONCLUSIONS

Long-term follow-up of the 1012 patients randomized to atherectomy or angioplasty has revealed a statistically significant excess of deaths after directional atherectomy that was not evident at 6 months. This difference could be due to the chance occurrence of a low mortality rate in those randomized to angioplasty. The excess of myocardial infarctions after atherectomy remains statistically significant at 1 year. Further investigation is warranted to improve the safety of atherectomy.

Time course of recombinant protein secretion after liposome-mediated gene transfer in a rabbit arterial organ culture model

BACKGROUND

Little information exists regarding the time course of gene expression after arterial transfection. Accordingly, we sought to determine the time course of gene expression after liposome-mediated arterial gene transfer (lipofectin) using an arterial organ culture model.

EXPERIMENTAL DESIGN

Explanted segments of rabbit descending thoracic aorta were maintained in organ culture. Arterial gene transfer, facilitated by cationic liposomes (Lipofectin), was performed with the plasmid pXGH5 encoding the human growth hormone (hGH) under the control of mouse metallothionein-1 promoter.

RESULTS

The time course of hGH production after transfection with the plasmid pXGH5 was evaluated. Significant levels (181.0 +/- 33.9 ng/24 hours/gm) of hGH were detected within 24 hours post-transfection, reached a peak on day 7 (238.4 +/- 35.3 ng/24 hours/gm), and declined after day 10. At day 21, hGH could be observed in 50% of the arteries. Immunostaining with a monoclonal antibody for hGH revealed that only a small number of arterial cells (< 1%) were responsible for production of hGH.

CONCLUSIONS

The organ culture model is a feasible and efficient means for investigating the kinetics of arterial gene transfer. Transfection of pXGH5 results in significant levels of hGH for up to 3 weeks, despite anatomic evidence of only limited gene expression. These data thus support the notion that the magnitude and/or duration of gene expression may be disproportionately high, relative to anatomic assessment of transfection efficiency in the case of a transgene encoding for a secreted protein.

Variable expression of the estrogen receptor in normal and atherosclerotic coronary arteries of premenopausal women

BACKGROUND

The relative absence of coronary atherosclerosis in premenopausal women has been established. Estrogen is presumed to play a role in the protection of coronary arteries from atherosclerosis, and part of this protective effect appears to be mediated by amelioration of serum lipid profiles. However, all of the atheroprotective effect of estrogen is not explained by alteration of serum lipids. In this study, we attempt to identify evidence of estrogen receptors in coronary artery specimens of female patients and in human vascular smooth muscle cells.

METHODS AND RESULTS

Postmortem coronary artery specimens were obtained from premenopausal (n = 18) and postmenopausal (n = 22) women who died with significant coronary artery disease (n = 19) and from noncardiac causes with normal coronary arteries (n = 21). Sections were examined for evidence of estrogen receptor expression using a monoclonal antibody stain. Radioligand binding assays for estrogen receptors were performed on human vascular smooth muscle cells in culture, and gel retardation assays were performed to confirm the presence of functional estrogen receptors. Estrogen receptor expression was identified by immunostaining in a total of 21 coronary arteries, with the majority of normal arteries (15 positive of 21 total, P = .0117) demonstrating evidence of estrogen receptor expression. Conversely, a minority (6 of 19, P = NS) of atherosclerotic arteries were positive for estrogen receptor expression. Furthermore, the relation between estrogen receptor expression and absence of coronary atherosclerosis was most evident in premenopausal subjects, with 10 of 12 normal arteries in this group demonstrating evidence of estrogen receptors, whereas only 1 of 6 atherosclerotic coronary arteries was positive (P = .0062). Radioligand binding assays confirmed the presence of estrogen receptors at significant concentrations in intact human vascular smooth muscle cells. Gel retardation assays also documented the presence of functional estrogen receptors in extracts from human vascular smooth muscle cells.

CONCLUSIONS

This investigation provides evidence of estrogen receptors in smooth muscle cells from human coronary arteries. The demonstrated relation between the presence of the receptors and the absence of atherosclerosis in premenopausal women suggests that these receptors may play a functional role in coronary atheroprotection.

Use of the rabbit ear artery to serially assess foreign protein secretion after site-specific arterial gene transfer in vivo. Evidence that anatomic identification of successful gene transfer may underestimate the potential magnitude of transgene expression

BACKGROUND

The development of molecular strategies for the treatment of restenosis has been hindered by low efficiencies of in vivo arterial transfection. Expression of intracellular marker proteins is generally evident in < 1% of vascular smooth muscle cells after in vivo arterial transfection. Efforts to improve the efficiency of in vivo gene transfer have been further impeded by the use of transgenes encoding for intracellular marker proteins, necessitating tissue removal and limiting survey for expression to one point in time.

METHODS AND RESULTS

To study gene expression on a serial basis in vivo and determine the relation between a secreted gene product and transfection efficiency after in vivo arterial gene transfer, a method for performing and serially monitoring gene expression in vivo was developed using the central artery of the rabbit ear. Liposome-mediated transfection of plasmid DNA containing the gene for human growth hormone (hGH) was successfully performed in 18 of 23 arteries. Serum hGH levels measured 5 days after transfection ranged from 0.1 to 3.8 ng/mL (mean, 0.97 ng/mL); in contrast, serum drawn from the control arteries demonstrated no evidence of hGH production. Serial measurement of hGH from transfected arteries demonstrated maximum hGH secretion 5 days after transfection and no detectable hormone after 20 days. Despite these levels of secreted gene product documented in vivo, immunohistochemical staining of sections taken from the rabbit ear artery at necropsy disclosed only rare cells in which there was evidence of successful transfection.

CONCLUSIONS

These experiments demonstrate a useful method of performing serial in vivo analyses of gene expression after vascular transfection and that anatomic analyses of transfection efficiency may underestimate the potential magnitude of expression in the case of a secreted gene product. These findings have implications for the clinical application of somatic gene therapy because low-efficiency transfection with a gene encoding for a secreted protein may achieve therapeutic effects not realized by transfection with genes encoding for proteins that remain intracellular.

Therapeutic angiogenesis. A single intraarterial bolus of vascular endothelial growth factor augments revascularization in a rabbit ischemic hind limb model

Vascular endothelial growth factor (VEGF) is a heparin-binding, endothelial cell-specific mitogen. Previous studies have suggested that VEGF is a regulator of naturally occurring physiologic and pathologic angiogenesis. In this study we investigated the hypothesis that the angiogenic potential of VEGF is sufficient to constitute a therapeutic effect. The soluble 165-amino acid isoform of VEGF was administered as a single intra-arterial bolus to the internal iliac artery of rabbits in which the ipsilateral femoral artery was excised to induce severe, unilateral hind limb ischemia. Doses of 500-1,000 micrograms of VEGF produced statistically significant augmentation of collateral vessel development by angiography as well as the number of capillaries by histology; consequent amelioration of the hemodynamic deficit in the ischemic limb was significantly greater in animals receiving VEGF than in nontreated controls (calf blood pressure ratio, 0.75 +/- 0.14 vs. 0.48 +/- 0.19, P < 0.05). Serial angiograms disclosed progressive linear extension of the collateral artery of origin (stem artery) to the distal point of parent vessel (reentry artery) reconstitution in seven of nine VEGF-treated animals. These findings establish proof of principle for the concept that the angiogenic activity of VEGF is sufficiently potent to achieve therapeutic benefit. Such a strategy might ultimately be applicable to patients with severe limb ischemia secondary to arterial occlusive disease.

[Pleuropulmonary actinomycosis]

A previously healthy 42 years old male was admitted to hospital with chest pain. Chest radiograms revealed a solid mass in the left thoracic cavity. A lung biopsy showed findings consistent with probable actinomycosis. It was feared that the specimen was not representative and a left upper lobe lobectomy was performed. This confirmed the diagnosis of actinomycosis. The patient was postoperatively treated with penicillin and tetracycline and has remained well during a follow-up period of two years.

Suitable screening tests for cognitive impairment and depression in the terminally ill--a prospective prevalence study

Although confusional states and depression are common accompaniments of advanced cancer, few objective data are available concerning the prevalence of these clinical states or what methods are most suitable for their accurate detection. We decided that a 10-question Abbreviated Mental Test Score (AMTS) and a semistructured application of modified DSMIII-R (Diagnostic and Statistical Manual of Mental Disorder, third edition-revised) criteria for a major depressive illness were the most suitable screening tests for a terminally ill population. Thirty of 87 patients (34%) displayed significant cognitive impairment. The AMTS rating declined with approaching death and also correlated negatively with age. Of 81 patients, 21 (26%) were depressed when screened using DSMIII-R criteria for depression. One-third of patients with impaired AMTS scores also satisfied DSMIII-R criteria for depression. Of cognitively impaired patients, 90% had at least two possible causes for their confused state. We have found that both the AMTS and semistructured interview using DSMIII-R criteria for depression are useful routine screening tests in the terminally ill.

Single daily bottle use in the early weeks postpartum and breast-feeding outcomes

A prospective study of breast-feeding mothers was undertaken to determine the effects of limited bottle use and infant temperament on breast-feeding outcomes. White, married, primigravida women who were committed prenatally to breast-feeding for at least 6 weeks (n = 121) were randomly assigned to one of two groups: a planned bottle group that would offer one bottle daily between the second and sixth weeks postpartum and a total breast-feeding group that would avoid bottles during the same period. Group assignment had no effect on the occurrence of breast-feeding problems, on mothers' achievement of 90% of their prenatal breast-feeding duration goals, or on weeks to weaning across the study period. At 6 months postpartum, 59% of the planned bottle group and 69% of the total breast-feeding group were still breast-feeding. No main or interactive effects of infant temperament on breast-feeding outcomes were found.

Expression of transforming growth factor-beta 1 is increased in human vascular restenosis lesions

Human atheromata obtained in vivo were used to test the hypothesis that transforming growth factor-beta 1 plays a role in the development of vascular restenosis. We analyzed 28 specimens from patients with primary atherosclerotic or restenotic lesions; 26 of these were obtained by directional atherectomy and 2 at the time of coronary bypass surgery. Seven control tissues included operatively excised segments of human internal mammary artery, myocardium, and unused portions of vein graft obtained intraoperatively. From these 35 specimens, 210 sections were examined using in situ hybridization. Measurement of silver grains/nucleus disclosed that expression of transforming growth factor-beta 1 mRNA was highest in restenotic tissues (P < 0.001 vs. primary atherosclerotic tissues) and lowest in nonatherosclerotic (control) tissues. In cultures of human vascular smooth muscle cells grown from explants of internal mammary artery, expression of mRNA for transforming growth factor-beta 1 was significantly greater in subconfluent than in confluent smooth muscle cells (P = 0.05). Transforming growth factor type-beta III receptor was expressed in cell cultures and undetectable in the tissue specimens. Sections taken adjacent to those studied by in situ hybridization were examined by immunohistochemistry using antibodies against transforming growth factor-beta 1 and alpha-actin (as a marker for smooth muscle cells) and disclosed transforming growth factor-beta 1 in smooth muscle cells present in these sections. These findings are consistent with the concept that transforming growth factor-beta 1 plays an important role in modulating repair of vascular injury, including restenosis, after balloon angioplasty.

Management of the final 24 hours

The management of the final 24 hours of life of 100 patients, dying in Our Lady's Hospice is reviewed. This review suggests that management might be improved by better contact between general hospitals and hospice/home care teams concerning the timing of patient transfer. The frequency of symptoms in the dying patient, even where many are semi-comatose, is highlighted. The main distressing symptoms are pain, excessive respiratory secretions and agitation. Our review confirms reliance on standard palliative medications such as morphine, however identifies the benefit of such newer preparations as hydromorphone and midazolam. Management might be improved by the earlier usage of hyoscine subcutaneously and stopping the use of intramuscular diazepam. Attention to potential hyoscine toxicity and untreated pyrexia may ease pre-terminal agitation. The dying patient's family also needs attention to complete the optimal management of the final 24 hours.

In vivo assessment of vascular pathology resulting from laser irradiation. Analysis of 23 patients studied by directional atherectomy immediately after laser angioplasty

BACKGROUND

The pathological consequences of cardiovascular laser irradiation have been studied extensively in vitro. Previous in vivo studies of laser-induced injury have included analyses of acute and/or chronic findings in experimental animals. Little information, however, is available regarding the acute effects of laser irradiation of human vascular tissues in vivo.

METHODS AND RESULTS

To determine the acute pathology resulting from laser irradiation of human vascular tissue in vivo, specimens retrieved from 23 patients by directional atherectomy immediately after laser angioplasty (19 peripheral and four coronary) were examined by light microscopy. Of the 23 patients, three (13.0%) were treated with a metal-capped ("hot-tip") fiber coupled to a continuous-wave neodymium:yttrium-aluminum-garnet (Nd:YAG) laser using up to 18 W power and 18-305 seconds of cumulative exposure time; in all three patients (100%), thermal injury, including frank charring several cell layers thick, was seen along the luminal borders of the atherectomy specimen. In eight of the 23 patients (34.5%), laser angioplasty was performed using a 250-microseconds holmium:YAG laser at fluences up to 2,300 mJ/mm2, a repetition rate of 5 Hz, and 25-200 seconds of cumulative exposure; in seven of eight patients (85.5%), the atherectomy specimen showed signs of vacuolar injury consisting of central and satellite Alcian-blue-negative vacuoles. In two patients (25.0%), there was a "smudged" or "shredded" edge, whereas in one patient, frank signs of thermal injury were observed. Finally, in 12 of the 23 patients (52.2%), laser angioplasty was performed using a 120-nsec excimer laser at fluences up to 60 mJ/mm2, a repetition rate of 25 Hz, and a cumulative exposure time of 21-315 seconds. Pathological findings among these 12 patients were limited to nine patients (75%) in whom a weakly basophilic, smudged, and/or shredded appearance approximately one cell layer thick was observed along the luminal border of the atherectomy specimen and two patients (16.7%) with small foci of vacuolar injury. None of the atherectomy specimens retrieved after excimer laser angioplasty disclosed signs of thermal injury.

CONCLUSIONS

These findings document that acute pathological alterations resulting from in vivo laser angioplasty are variable, depending on the laser source used, and are similar to that predicted by experimental studies performed previously in vitro. The prognostic implications of these varying pathological features remain to be clarified.

Evidence implicating nonmuscle myosin in restenosis. Use of in situ hybridization to analyze human vascular lesions obtained by directional atherectomy

BACKGROUND

Identification of genes that are specifically activated in restenosis lesions after percutaneous transluminal angioplasty represents a necessary step toward molecular manipulation designed to inhibit cellular proliferation responsible for such lesions. Whereas quiescent smooth muscle cells (contractile phenotype) preferentially express smooth muscle myosin, proliferating smooth muscle cells (synthetic phenotype) have been shown to preferentially express nonmuscle myosin in vitro. Accordingly, we analyzed the expression of a recently cloned isoform of human nonmuscle myosin heavy chain (MHC-B) in fresh human restenotic lesions.

METHODS AND RESULTS

A total of 10 lesions, including four restenosis (three superficial femoral arterial lesions and one saphenous vein bypass lesion) and six primary (four superficial femoral arterial lesions and two coronary arterial lesions) obtained percutaneously by directional atherectomy, were processed for examination by in situ hybridization. In total, 150 tissue sections of restenotic lesions (66 sections), primary lesions (78 sections), and normal internal mammary artery (six sections) were hybridized with the nonmuscle MHC-B probe. Restenotic lesions showed intense hybridization to the nonmuscle MHC-B cRNA probe, as demonstrated by a clustering of more than 20 grains per cell nucleus in 80% of the cells examined within a high-power field (x250); in contrast, an equivalent degree of hybridization was observed in only 7% of cells within primary lesions (p less than 0.001). Results of immunocytochemistry using monoclonal antibody to smooth muscle actin indicated that cells demonstrating strong hybridization were smooth muscle in origin.

CONCLUSIONS

These findings demonstrate that 1) human vascular tissue obtained by percutaneous directional atherectomy constitutes appropriate biopsy material for gene expression studies at the mRNA level, and 2) nonmuscle MHC-B mRNA is present in greater abundance among restenotic versus primary vascular stenoses. These observations thus provide a rational basis to explore restenotic lesions on a larger scale to identify genes that are activated in these lesions and establish potential targets for future gene therapy.

Remote frozen section service: a telepathology project in northern Norway

We discuss the organization of a remote frozen section service in northern Norway. The service is operated by remote control of a motorized video-microscope located at Kirkenes Hospital, at a distance of more than 400 km from the workstation at the University Hospital in Tromsø. The video images of the frozen section are transmitted via a two-way telephone and video telenetwork with a 2 Mbit/s capacity. The images are displayed on monitors and diagnosed by pathologists in Tromsø. To date, 17 patients have been examined by remote frozen section. Correct benign versus malignant diagnoses have been given in all 17 cases compared with final diagnoses based on formalin-fixed and paraffin-embedded material. The average time taken for examining each frozen section was 15 minutes (range, 5 to 30 minutes). In none of the cases was the interpretation of the slides difficult due to deficient quality of the video images. For small hospitals with limited availability of local pathology services and for hospitals with a deficiency of specialists, telepathology may be a worthwhile substitute.

National survey of clinical and subclinical mastitis in Jamaican dairy herds, 1985-1986

Between April 1985 and August 1986, 89 Jamaican dairy herds with 10 or more cows were visited, 1,645 lactating cows were examined using the CMT test and 254 composite milk samples collected for bacteriological examination. Widespread management faults were noted, especially of milking machine usage and maintenance and the abuse of antibiotics. Fifty-six per cent of all quarters were found to have CMT scores of one or higher, 0.8% showed clinical mastitis and 3.2% were blind. The most common bacterial pathogen Staphylococcus aureus, was recovered from 31% of sampled cows. The resultant milk loss from clinical and subclinical mastitis was estimated to be 20% of the potential national production.

Evaluation of a mass measles immunisation campaign in a rapidly growing peri-urban area

A mass measles immunisation campaign, with a target coverage rate of 85-90%, was launched in Khayelitsha, a rapidly growing urban township in the Cape Town area. Cross-sectional surveys of the measles immunisation status of resident 6-23-month-old infants were conducted immediately before, immediately after, and approximately 2 months after the campaign in order to determine the effectiveness of a mass campaign in boosting coverage in an area with a high influx rate. Immunisation coverage rates were 55% in the first survey, 76% in the second, and 72% in the third. In the first survey, coverage rates for children born in Cape Town were 1.4 times higher than those born elsewhere. This trend continued throughout the survey. Duration of stay in Cape Town also influenced coverage, with rates for the recently arrived children being considerably lower than those for the more established Cape Town residents. The influx rate between the second and third survey (over the Christmas period) was 9.1% per month. Failure to reach the targeted rate is attributed to the influx rate, campaign design and implementation, and factors related to child and career mobility. Alternative immunisation strategies, with social awareness playing a key role, are being urgently investigated.

Mechanism of death in avalanche victims

The autopsies of 12 victims from two snow avalanches in North-Norway are reported. Supportive evidence from non-autopsied and surviving victims is included. Consistent autopsy findings were prominent lung oedema, moderate cerebral oedema, extreme contraction of the left ventricle, petechiae in the superior vena cava drainage area, and acute congestion in lungs and kidneys. In four cases in whom no resuscitation was attempted, aortic oxygen pressure was in the range expected in pure asphyxial-type deaths in one and in pure cardiac-type deaths in three. No air pocket was seen in front of the mouth and nose in any of the fatal cases. Three fatal cases had fractures. It is concluded that the immediate cause of death in most cases was general body compression with acute respiratory and circulatory failure.

Urinary gamma-glutamyl transpeptidase activity in dogs with gentamicin-induced nephrotoxicity

Serum creatinine concentrations, 24-hour endogenous creatinine clearance, and 24-hour urinary gamma-glutamyl transpeptidase (UGGT) activity were measured daily in 6 dogs given nephrotoxic dosages of gentamicin (10 mg/kg of body weight) every 8 hours for 10 days. Mean UGGT activity was significantly increased by day 5 (P less than 0.05) and preceded significant increases in serum creatinine values (greater than 2.0 mg/dl) observed on day 9. Endogenous creatinine clearance remained within normal limits (2.98 +/- 0.96 ml/min/kg) until day 8. Urinalyses performed 8 days after initiation of gentamicin treatment indicated renal tubular damage (granular casts) in 1 of the 6 dogs, and glucosuria in 3 of the 6 dogs. Measurement of UGGT activity was a more sensitive and reliable method of assessing acute renal tubular damage induced by gentamicin than were serum creatinine concentrations or 24-hour endogenous creatinine clearance.

Proteinlosing gastropathy with gastric hypersecretion of acid (H+) and pepsin and hypergastrinemia. A case report

A case with proteinlosing gastropathy with gastric hypersecretion of H+ and pepsin as well as hypergastrinemia is presented. Zollinger-Ellison syndrome was excluded by reduction in acid secretion and serum gastrin during the observation period as well as by the effect on gastric secretion and serum gastrin after injections of secretin and glucagon.