Sticky stuff: biological cohesion for scour and erosion prevention

This study examines the potential for biological cohesion to arrest scour erosion at marine infrastructure. Biological cohesion occurs naturally in sedimentary environments, and is caused by extracellular polymeric substances (EPS) which result from the life cycles of microorganisms. EPS is known to dramatically increase the resistance of natural biomediated sediment to erosive hydrodynamic forces. In this study, we test, for the first time, whether EPS can be deliberately added to a sediment to mitigate against scour erosion - a process we term 'biostabilisation'. A systematic laboratory experiment is used to investigate the effects of an EPS additive on scour erosion around a monopile in a sand substrate. Results show that increasing EPS content causes a progressive reduction in equilibrium scour depth, the volume of excavated material and the timescale required to reach equilibrium scour morphology. These parameters are linearly related to EPS content, showing that the effects of EPS on the physical processes required for erosion to occur are concentration dependent. It can be concluded that biostabilisation offers a potential new ecologically engineered, nature-based solution to a range of scour and erosion scenarios. The economic and environmental advantages are discussed, and a methodology for biostabilisation use in individual erosion mitigation scenarios is proposed.

Charcot neuroarthropathy triggered by osteomyelitis and/or surgery

INTRODUCTION

Charcot neuroarthropathy (CN) is a rare but devastating complication of diabetic neuropathy. Osteomyelitis is also a complication of the diabetic foot and it may be difficult to differentiate from CN.

PATIENTS AND METHODS

A patient with Type 1 diabetes and peripheral neuropathy developed a foot ulcer complicated by osteomyelitis of the first proximal phalanx. He was successfully treated with antibiotics and surgical excision of the infected bone. Six months later, he developed a hot, swollen, red foot and X-ray showed destruction of the second and third metatarsal heads. At the second presentation, it was difficult to determine whether this was a recurrence of osteomyelitis or a new onset of CN. Thus, to obtain a definitive diagnosis, recourse was made to more sophisticated imaging techniques.

RESULTS

99mTc methylenediphosphonate (MDP) bone scans and magnetic resonance imaging proved inconclusive to differentiate between osteomyelitis and CN. Subsequently, an indium-labelled white cell scan confirmed the absence of osteomyelitis and the patient was successfully treated for CN.

DISCUSSION

Infection and/or surgery may be predisposing factors in the development of diabetic CN but the combination of the two could accelerate the onset of the Charcot process in people with diabetes and neuropathy.

Giant splenic artery aneurysm associated with arteriovenous malformation

Giant splenic artery aneurysms are extremely rare entities that have important clinical implications. The size and the natural history pose unique challenges in the management of these lesions. We present one such case that was associated with a primary arteriovenous malformation in the splenic hilum. This is the third largest aneurysm reported in literature so far and the characteristic feature is that this is the first case of a hilar arteriovenous fistula complicated by formation of a giant aneurysm and another smaller aneurysm. In our opinion the hilar malformation was congenital in origin and responsible for the formation of the two aneurysms. We also present an up to date review of literature on this subject.

Intra-articular chondroma of the knee

Chondromas are tumours that develop in relation to the periosteum and, although they are common around the knee, most reports deal with soft tissue chondromas in para-articular locations or intracortical tumours in extra-articular regions. We report a rare case of an intra-articular chondroma in a 16-year-old boy of Asian origin developing in the region of the medial femoral condyle of the femur and extending into the femoral sulcus and the patellofemoral joint.

Latitude and noise comparisons between digital cameras and a radiographic film scanner

The test image generated by a radiographic laser printer was used as a test object to measure the latitude and image noise of two digital cameras and a dedicated radiographic film scanner. The film scanner had the widest latitude and least image noise. A Kodak digital camera had a wider latitude but more image noise than an Olympus camera. A blue filter on the Olympus camera increased the latitude without significant increase in image noise.

Upregulation of basic fibroblast growth factor in breast carcinoma and its relationship to vascular density, oestrogen receptor, epidermal growth factor receptor and survival

BACKGROUND

Angiogenesis, the process whereby endothelial cells divide and migrate to form new blood capillaries, has been assessed in tumours by measuring microvessel density. High microvessel density is a significant adverse prognostic factor in breast cancer. The angiogenic factor, basic fibroblast growth factor (bFGF), has been associated with tumourigenesis and metastasis in several human cancers. There are few quantitative studies of bFGF expression in normal tissues compared to cancer.

PATIENTS AND METHODS

We have measured bFGF levels in 149 human primary breast carcinomas and assessed the findings in relation to microvessel density, oestrogen receptor (ER) and epidermal growth factor receptor (EGFR). Basic FGF levels were measured by ELISA. Western blotting and immunohistochemistry were carried out to confirm the presence of bFGF.

RESULTS

Levels of bFGF were more than 10-fold higher in tumour cytosols compared to reduction mammoplasty tissue and 3-fold compared to non neoplastic cytosols from the same breast as the tumour (P < 0.0001). Immunohistochemistry showed bFGF protein was localised exclusively in the stroma whereas no bFGF staining was observed in the epithelial cells. High bFGF levels were significantly related to high ER (P = 0.01). Similarly, high bFGF levels were significantly related to low grade (P = 0.046) and to small tumour size (P = 0.04). No significant relationship was observed between bFGF and microvessel count, EGFR or age. In univariate analysis and in a Cox proportional hazard model bFGF did not reach significance for overall or relapse free survival.

CONCLUSIONS

Our results show that although bFGF is elevated in breast carcinomas compared to normal breast tissue it is not related to microvessel density and it is not an independent predictor of survival in breast cancer patients. Basic FGF may be one of multiple factors that synergise with other growth factors such as VEGF to enhance angiogenesis.

Tumor angiogenesis in stage II colorectal carcinoma: association with survival

We studied the frequency of microvessels in T3 N0 M0 colorectal carcinomas from patients with widely different survival times. Microvessels (<50 microm diameter) were enhanced by immunostaining with antibody to factor VIII-related antigen and counted in 40x high-power fields in sections of resected carcinomas from 9 patients who died of disease in 24 months or less (short-term survivors) and 13 who had no evidence of disease at 109 months or longer (long-term survivors). The means of the 10 highest counts for each case were compared between the long- and short-term survivor groups. The mean +/- SD microvessel count was 25.4 +/- 6.5 for the short-term survivors and 30.3 +/- 6.4 for the long-term survivors. Median counts were 27.2 and 29.4, respectively. The distribution of microvessel counts was skewed toward higher counts in the long-term survivors. There was no correlation between microvessel counts and tumor site, size, or grade; lymphovascular invasion; or the presence of a mucinous component. Although there was a trend toward a higher frequency of microvessels in patients with longer survival, it is unlikely that microvessel count is an independent prognostic indicator for patients with T3 N0 M0 colorectal carcinoma because there is only a small difference in microvessel frequency between patients with widely different survival times.

Bcl-2 protein expression: association with p53 and prognosis in colorectal cancer

Bcl-2 expression in colorectal carcinomas was studied in a series of 224 patients and the relation to p53 expression, stage and survival assessed. Bcl-2 expression was down-regulated compared with normal mucosa in 67% (151) of the cases. In 144 cases staining was positive for p53 (MAB DO7), and 41 of these 144 p53-positive cases were also bcl-2 positive (28%) compared with 32 of the remaining 80 p53-negative cases (40%). Survival was significantly worse (P = 0.01) in the p53-positive cases. Bcl-2-positive cases, including patients in all Dukes' stages, had a slightly better prognosis which was not statistically significant. However, cases at an early stage (Dukes' stages A and B) and with negative p53 status, had a much better prognosis if they showed bcl-2 protein expression, suggesting that the bcl-2 status itself has an effect on prognosis (P = 0.01). Neither bcl-2 nor p53 alone was correlated with stage, but when examined by both p53 and bcl-2 status a group [bcl-2(+)/p53(-)] with better prognosis was defined. The last group was significantly lower Dukes' stage, with 26 out of 32 cases (81%) being A or B compared with 22 (11%) of the 202 remaining cases (P = 0.004). Thus, either loss of bcl-2 expression or gain of abnormal p53 expression is associated with high stage and poor prognosis. The bcl-2(+)/p53(-) phenotype is similar to that of normal mucosa, and these results suggest that such cases represent an indolent group at an early stage in the progression of colorectal cancer.

Calcific tendinitis of the gluteus maximus tendon with abnormalities of cortical bone

Calcific tendinitis of the gluteus maximus tendon is unusual and only eight cases associated with erosions of cortical bone have been reported. We present three further cases which demonstrate variation in appearances of the amorphous calcification in the tendon and cortical erosions on plain radiographs. Isotope bone scans show focal increased activity and computed tomography (CT) clearly demonstrates erosion of cortical bone and calcification within the tendon insertion of gluteus maximus. Follow-up examinations in two cases demonstrated resolution of the changes. We believe this series demonstrates the radiological features and natural history of a common condition occurring at an unusual site. Its recognition is important in order to avoid unnecessary surgical intervention. Resolution of the calcification and cortical erosions has not been previously described.

Expression of the angiogenic factors vascular endothelial cell growth factor, acidic and basic fibroblast growth factor, tumor growth factor beta-1, platelet-derived endothelial cell growth factor, placenta growth factor, and pleiotrophin in human primary breast cancer and its relation to angiogenesis

Angiogenesis is a significant prognostic factor in breast cancer, but the factors that control angiogenesis in vivo are not well defined. Multiple angiogenic polypeptides are known, and we have determined the expression of seven of these in primary human breast cancers; the relationship of expression to estrogen receptor and vascular density was also examined. Vascular endothelial growth factor (VEGF) and its four isoforms (121, 165, 189, and 206 amino acids), transforming growth factor (TGF)-beta1, pleiotrophin, acidic and basic fibroblast growth factor (FGF), placental growth factor, and thymidine phosphorylase (platelet-derived endothelial cell growth factor) were quantitated by RNase protection analysis. beta-FGF was also measured by ELISA. The estrogen receptor (ER), epidermal growth factor receptor, and vascular density were analyzed in 64 primary breast cancers. All tumors expressed at least six different vascular growth factors. VEGF was most abundant, and the transcript for the 121-amino acid form predominated. Other angiogenic factors expressed at high levels were thymidine phosphorylase and TGF-beta1. Expression of most of the angiogenic factors did not correlate with that of ER or vascular density. However, thymidine phosphorylase did, with a correlation coefficient of 0.3 (P = 0.03). There were significant associations of pleiotrophin with acidic FGF expression (P = 0.001) and TGF-beta with platelet-derived endothelial cell growth factor expression (P = 0.001). Thus, angiogenesis may involve a coordinate regulation of some vascular growth factors. High VEGF expression correlated with poor prognosis in univariate analysis (P = 0.03), as did ER and epidermal growth factor receptor expression. Basic FGF was also assessed by ELISA and was more highly expressed in tumors than normal breast tissues (median, 346 microg/ml cytosol; range, 54-1323 versus median, 149; range, 32-509; P = 0.01). Implications for therapy are that broad spectrum agents that block features common to these factors may be useful (e.g., antagonism of heparin-binding activity agents), because so many angiogenic factors are expressed. Inhibiting endothelial migration or agents directly toxic to endothelium would be of value in a combined approach to therapy.

Non-small cell lung cancer: c-erbB-2 overexpression correlates with low angiogenesis and poor prognosis

Tumour angiogenesis is an important prognostic factor in non-small cell lung cancer. Recently, EGFR and c-erbB-2 protein was found to regulate cell adhesion and the invasive growth of cancer through its association with the cadherin-catenin complex. The role of c-erbB-2 protein in cell migration has been also reported. In this study we investigate the combined role of tumoral neoangiogenesis and c-erbB-2/EGFR expression in the metastatic behaviour and prognosis of operable non-small cell lung cancer. 107 tumour samples from patients suffering from operable non small cell lung cancer were examined. EGFR and c-erbB-2 were not correlated with each other. C-erbB-2 expression was associated with low angiogenesis, approaching statistical significance in adenocarcinomas (p = 0.08). The absence of expression of both c-erbB-2 and EGFR oncogenes in tumours with high angiogenesis, was most frequently observed in node negative cases (p = 0.04). C-erbB-2 overexpression defined a subgroup of node negative patients with low angiogenesis and prognosis similar to patients with tumours bearing high angiogenesis. These findings support the hypothesis that expression of the erb genes is a mechanism activated in non-small cell lung cancer to enable cancer cell migration. This pathway seems to be activated mainly in tumours with poor vasculature presumably lading to an unfavourable intratumoral nutritional and oxygen ambience.

Loss of interleukin 4 receptor-associated molecule gp200-MR6 in human breast cancer: prognostic significance

Several in vitro studies stress a potentially important role of interleukin 4 (IL-4) and the related gp200-MR6 molecule in the immunological response to cancer and in tumour proliferation. In the present study, we assessed the expression of gp200-MR6 in primary breast cacrinomas using the MR6 monoclonal antibody. Results were correlated with tumour parameters (T-,N-stage, histology, grade, oestrogen and epidermal growth factor (EGF) receptors), and the impact on survival was assessed. Twenty-four out of 110 cases (22%) were positive for gp200-MR6, 62 out of 110 (56%) expressed weak staining and 24 out of 114 (22%) did not stain. The normal breast epithelia were invariably stained for gp200-MR6 showing that down-regulation or loss of this molecule occurred during the evolution of breast cancer. Gp200-MR6 loss was independent from differentiation, nodal positivity and oestrogen receptor levels as well as patients' age. Loss of the gp200-MR6 molecule was more frequent in lobular cases (P=0.03). The overall survival was better, although not reaching statistical significance, in patients with positive gp200-MR6 expression (92% alive at 5 years compared with 70% for those with weak or no expression, P=0.1). The local relapse-free survival was independent of gp200-MR6 status. It is concluded that loss of gp200-MR6 may be one of the mechanisms through which breast cancer cells escape immune surveillance, resulting in an increased metastatic potential and poorer outcome. Evidence of down-regulation of the gp200-MR6 molecule has implications for IL-4-linked toxin therapy and, as IL-4 is an inhibitor of breast epithelial growth, may represent loss of a tumour-suppression mechanism.

Association of macrophage infiltration with angiogenesis and prognosis in invasive breast carcinoma

Angiogenesis is a key process in tumor growth and metastasis and is a major independent prognostic factor in breast cancer. A range of cytokines stimulate the tumor neovasculature, and tumor-associated macrophages have been shown recently to produce several important angiogenic factors. We have quantified macrophage infiltration using Chalkley count morphometry in a series of invasive breast carcinomas to investigate the relationship between tumor-associated macrophage infiltration and tumor angiogenesis, and prognosis. There was a significant positive correlation between high vascular grade and increased macrophage index (P = 0.03), and a strong relationship was observed between increased macrophage counts and reduced relapse-free survival (P = 0.006) and reduced overall survival (P = 0.004) as an independent prognostic variable. These data indicate a role for macrophages in angiogenesis and prognosis in breast cancer and that this cell type may represent an important target for immunoinhibitory therapy in breast cancer.

Differential expression of the topoisomerase II alpha and beta genes in human breast cancers

Topoisomerase II is a key target for several anti-cancer drugs used for breast cancer therapy, including doxorubicin, epirubicin and mitoxantrone. Two isoforms of topoisomerase II (alpha and beta) have been described in human cells which differ in their subcellular localisation, biochemical properties and susceptibility to inhibition by anti-cancer drugs. The relative level of expression of the alpha and beta isoforms may contribute to the degree of tumour responsiveness to different chemotherapeutic agents. To assess the relationship between expression of topoisomerase II isoforms and established prognostic factors and pathological variables, 56 primary breast tumour samples were studied. The expression of the two topoisomerase II genes was apparently not co-ordinately regulated in these tissue samples. There was no relationship between any of the commonly used pathological variables [tumour size, lymph node status, S-phase fraction (SPF)] and the level of expression of topoisomerase II beta mRNA. However, high topoisomerase II alpha gene expression was significantly associated with a high SPF (sign-rank test; P = 0.01). Moreover, the ratio of mRNA levels for topoisomerase II alpha and beta showed a stronger relationship to SPF (median raito 0.62 for tumours with SPF < 10, and 1.64 for SPF > 10; P = 0.0021, sign-rank test). As expected from previous studies, an SPF > 10 was associated with poor overall survival (P = 0.01). Immunohistochemical analysis revealed that topoisomerase II beta was widely distributed ( > 90% positive tumour cells), but that topoisomerase II alpha expression was less widely expressed, with a pattern of expression similar to that of the proliferation-dependent antigen recognised by Ki67. Because topoisomerase II gene expression showed a log-normal distribution, log-transformed data were used in multivariate analysis of relapse-free survival. This showed that lymph node status and topoisomerase II beta mRNA expression were the only significant survival factors (P = 0.001 and 0.05, respectively, with relative risks of 1.3 and 1.8). These results indicate that topoisomerase II alpha, but not beta, expression is dependent upon cellular proliferation status, but that the more widely expressed topoisomerase II beta protein may play a significant role as a target for anti-tumour therapy.

Early expression of bcl-2 protein in the adenoma-carcinoma sequence of colorectal neoplasia

bcl-2 was originally identified as an oncogene involved in follicular lymphomas as a result of chromosomal translocation (14;18). It is now believed that bcl-2 is implicated in the regulation of cell death by inhibiting apoptosis and that its expression is not restricted to haematopoietic cells, but is also present in many epithelial and mesenchymal tissues. Recent studies have analysed the expression of this molecule in a variety of non-lymphoid malignancies including lung, breast, prostate, and nasopharyngeal carcinomas and neuroblastoma. In the present study, 50 colorectal adenomas, 10 hyperplastic polyps, and 142 carcinomas, including 25 arising from pre-existing adenomas, were examined using an antibody detecting the bcl-2 protein product. In non-neoplastic mucosa, bcl-2 was expressed in the crypt cells only, whilst the more differentiated surface epithelial cells lacked any demonstrable bcl-2. Forty-one of the 50 adenomas (82 per cent) and 48 of the 142 carcinomas were positive for bcl-2 expression. All hyperplastic polyps were negative. A reciprocal relationship was found between bcl-2 reactivity and p53 overexpression, as detected by DO7 antibody, in approximately 65 per cent of the cases. The bcl-2-positive/p53-negative subgroup showed a strong correlation (P = 0.0056) with negative lymph node status (Dukes' A and B), implying a less aggressive pathway of neoplastic transformation.

Prognostic value of angiogenesis in operable non-small cell lung cancer

Tumour angiogenesis is an important factor for tumour growth and metastasis. Although some recent reports suggest that microvessel counts in non-small cell lung cancer are related to a poor disease outcome, the results were not conclusive and were not compared with other molecular prognostic markers. In the present study, the vascular grade was assessed in 107 (T1,2-N0,1) operable non-small cell lung carcinomas, using the JC70 monoclonal antibody to CD31. Three vascular grades were defined with appraisal by eye and by Chalkley counting: high (Chalkley score 7-12), medium (5-6), and low (2-4). There was a significant correlation between eye appraisal and Chalkley counting (P < 0.0001). Vascular grade was not related to histology, grade, proliferation index (Ki67), or EGFR or p53 expression. Tumours from younger patients had a higher grade of angiogenesis (P = 0.05). Apart from the vascular grade, none of the other factors examined was statistically related to lymph node metastasis (P < 0.0001). A univariate analysis of survival showed that vascular grade was the most significant prognostic factor (P = 0.0004), followed by N-stage (P = 0.001). In a multivariate analysis, N-stage and vascular grade were not found to be independent prognostic factors, since they were strongly related to each other. Excluding N-stage, vascular grade was the only independent prognostic factor (P = 0.007). Kaplan-Meier survival curves showed a statistically significant worse prognosis for patients with high vascular grade, but no difference was observed between low and medium vascular grade. These data suggest that angiogenesis in operable non-small cell lung cancer is a major prognostic factor for survival and, among the parameters tested, is the only factor related to cancer cell migration to lymph nodes. The integration of vascular grading in clinical trials on adjuvant chemotherapy and/or radiotherapy could substantially contribute in defining groups of operable patients who might benefit from cytotoxic treatment.

C-erbB-2 oncoprotein expression in operable non-small cell lung cancer

Although c-erbB-2 oncoprotein immunohistochemical expression has been thoroughly studied in a variety of human tumors, its prognostic significance remains unclear. Moreover, differences in assessment criteria further complicate the evaluation of c-erbB-2 as a prognostic marker. In the present study we examined the expression of c-erbB-2 protein in 107 patients suffering from operable (T 1,2-N0, 1 staged) non-small cell lung cancer (30 adenocarcinomas and 69 squamous cell carcinomas) treated with surgery alone. A 3-7 year of follow up (median 45 months) was available for all patients. Paraffin embedded sections were stained with the NCL-CB11 monoclonal antibody using the immunoperoxidase technique. Analysis was based on cytoplasmic reactivity as membrane staining was impossible to assess against this background. Strong positive cytoplasmic staining was identified in 20/107 (19%) of cases, weak in 30/107 (20%) and negative in 57/107 (53%). Results were correlated with patient variables (age,sex) and tumor parameters (T,N-stage, grade, histology, Ki67 proliferation index, p53 and EGFR expression). C-erbB-2 expression was not related to any of these factors. Although c-erbB-2 defined a worse prognosis, univariate analysis of survival did not confirm any statistically significant difference between the c-erbB-2 staining groups (p=0.5). T,N-stage were the only statistically significant prognostic variables. Any contribution of c-erbB-2 to the development of tumour aggressive behaviour in non-small cell lung cancer requires assessment in the specific subgroups of patients.

A genetic register for von Hippel-Lindau disease

A genetic register for von Hippel-Lindau disease was set up in the north west of England in 1990. Population statistics, clinical features, age at onset, and survival of 83 people affected with von Hippel-Lindau (VHL) disease were studied. In addition, the effectiveness of the screening programme used and the occurrence of central nervous system haemangioblastomas in the general population were examined. The diagnostic point prevalence of heterozygotes in the North Western Region was 1 center dot 18/100 000 (1/85 000) people, with an estimated birth incidence of 2 center dot 20/100 000 (1/45 500) live births. The mutation rate was estimated directly to be 1 center dot 4 x 10(-6)/gene/generation (1/714 200). The mean age at onset of first symptoms was 26 center dot 25 years, with cerebellar haemangioblastoma being the most common presenting manifestation (34 center dot 9% of cases). The mean age at diagnosis of VHL disease was 30 center dot 87 years. Overall, 50 patients (60 center dot 2%) developed a cerebellar haemangioblastoma, 34 (41 center dot 0%) a retinal angioma, 21 (25 center dot 3%) a renal cell carcinoma, 12 (14 center dot 5%) a spinal haemangioblastoma, and 12 (14 center dot 5%) a phaeochromocytoma. Mean age at diagnosis of renal cell carcinoma (38 center dot 9 years) was significantly higher than that for cerebellar haemangioblastoma (30 center dot 0 years) and retinal angioma (21.1 years). Mean age at death was 40 center dot 9 years with cerebellar haemangioblastoma being the most common cause (47 center dot 7% of deaths). A total of 65 VHL manifestations were diagnosed asymptomatically following appropriate clinical and radiological screening tests, and failure to detect manifestations of VHL disease in spite of appropriate screening occurred on only two occasions. The use of DNA linkage analysis and direct mutation testing reduced the personal risk of carrying the VHL gene to below 1% in 14 people. In addition to the 83 clinically affected subjects, three obligate carriers who were considered to be lesion free in spite of extensive screening tests were identified. Fourteen percent of all CNS haemangioblastomas on the regionally based Cancer Registry were found to occur as part of VHL disease, but investigations for VHL in apparently sporadic disease appeared to be limited.

Children with juvenile rheumatoid arthritis at school. Functional problems, participation in physical education. The implementation of Public Law 94-142

Parents of 135 children with juvenile rheumatoid arthritis (JRA) completed a mailed questionnaire about problems at school. Writing was the most frequently reported difficulty, with hand involvement causing more problems than decreased mobility. Compared to children with pauciarticular JRA, those with polyarticular or systemic JRA were significantly more likely to miss school, experience problems, participate less in physical education, have an Individualized Educational Plan (IEP) developed, and receive related services. Only 39 parents had heard of PL 94-142, and only 21 of those could define the federal law. Twenty children had an IEP within the previous two years. Possible deficiencies in the implementation of PL 94-142 were discovered. This study demonstrates that the treatment of children with JRA should include efforts to: 1) identify and remediate potential performance limitations before they become problematic at school; 2) communicate this information to parents and school personnel; 3) and improve parents' awareness and understanding of PL 94-142.

Are postmortem studies of glossal candidal infection useful? An experimental study

Autopsy studies have suggested that candidal pseudohyphae may be found in dorsal glossal epithelium in 38% to 42% of cases. Candidal yeast forms, and occasionally free pseudohyphae, are found as oral commensals in about 44% of the population. This study examined the possible distorting influence in autopsy studies that could be caused by postmortem hyphal transformation of candidal yeast forms followed by saprophytic infestation. Candida albicans yeast forms were topically applied to the middorsal glossal mucosa of five healthy pigs, immediately after killing. Biopsy specimens from this mucosa were subsequently maintained, in vitro, for periods of 12 and 24 hours in humid conditions at different temperature regression rates chosen to approximate those of the oral cavity after death. Biopsy specimens subjected to a temperature regression of 35 degrees C (oral temperature) to 23 degrees C (room temperature) over 11 hours showed infestation of epithelium by pseudohyphae in all cases. Biopsy specimens subjected to a similar temperature regression over 5 hours showed infestation in two of five cases. Control biopsy specimens showed that there was no candidal infection at the time of killing. The results indicate that in vitro saprophytic candidal infestation is possible in the time intervals and the declining oral temperatures preceding autopsy. It suggests that postmortem saprophytic candidal infestation may distort results from autopsy studies that do not anticipate this problem.

Renal handling of zinc: effect of cysteine infusion

Zinc clearance studies in anesthetized dogs were performed during hydropenia, mannitol infusion, and infusion of mannitol plus ZnSO4, ZnCL2, or cysteine. Mannitol expansion caused no significant change in Zn clearance. ZnSO4 infusion increased filtered Zn 13-fold without changing clearance. Zn excretion increased only sixfold, indicating increased net Zn reabsorption. Cysteine infusion increased urinary Zn excretion 86-fold, indicating net tubular Zn secretion, some of which derived from nonplasma sources. Stop-flow studies localized Zn reabsorption to the distal nephron during infusion of mannitol and mannitol plus ZnSO4 or ZnCl2. Net Zn secretion was shown to occur in the proximal tubule during cysteine infusion with reversal of the distal reabsorption pattern seen during ZnSO4 and ZnCl2 infusion. Despite increased urinary Zn excretion during ZnSO4 infusion, calcium excretion was unaltered. During cysteine infusion dissociation of tubular handling of CA2+ and Zn occurred in both the proximal and distal tubule. These experiments demonstrate that the nephron under these experimental conditions is capable of both proximal secretion and distal reabsorption of Zn.

Blemishes developing on soft contact lenses

Suspected contamination of soft contact lenses lead to biological, X-ray spectrophotometric, and photographic investigations to attempt identification of substances which could not be cleaned from the lenses and which increased in number with time. All indications point to suspect contaminant not being foreign material but a breakdown of the polymer structure.

Uracil incorporation in the forespore and the mother cell during spore development in Bacillus subtilis. Autoradiographic electron microscopic study

The transcriptional activity of the two genomes of the sporangium during spore formation was determined by pulse-labeling bacteria with 3H-uracil at different times of sporulation and preparing them for high resolution autoradiography. The quantitative analysis of autoradiographs shows that uracile incorporation in the whole sporangium decreases considerably between stages II and IV. However, the variations of the transcriptional activity are not identical in the mother cell and in the forespore. The one of the mother cell decreases rapidly between stages II and III and then remains stable until the end of stage IV, whereas that of the forespore which is low at stage II increases as the forespore grows ovoid and then quickly diminishes. It is very weak at the beginning of stage IV and negligible at the end of this stage. Pulse-chase experiments made in the presence of rifampine indicate that about 30% of the uracile incorporated is located in stable RNA. This value is found at any stage of sporulation in both cellular compartments whatever their rate of uracile incorporation. A relationship can be made between the nuclear shape and the activity of the genetic material. This confirms observations made by several authors in other bacterial species and other physiological conditions that the condensed shape corresponds to a state of low transcriptional activity whereas the more irregular and dispersed shape corresponds to a state of high activity.