Effect of cycloheximide on the bone marrow toxicity of nitrogen mustard.

Cycloheximide (CHM), a potent inhibitor of protein synthesis, has been reported to protect rat intestinal crypt cells from mitotic inhibition by nitrogen mustard (HN2). For investigation of the effect of CHM on the bone marrow toxicity of HN2, CHM (1.0 mg/kg) and HN2 in doses up to 2.5 mg/kg were given i.p. to rats. Twenty-eight % (13 of 46) of rats given HN2 alone died within 5 days. Only 4% (2 of 45) of rats pretreated with CHM died within 5 days after the administration of HN2. Rats pretreated with CHM had significantly less leukopenia and granulocytopenia than did rats given HN2 alone, and their bone marrow cellularity, assessed by histological sections and total femoral marrow cell counts, was greater than that of animals given HN2 alone. Bone marrow DNA synthesis, as measured by in vitro [3H]thymidine incorporation, was decreased 2 hr after HN2 injection, appeared to recover at 4 hr, but was further decreased at 24 and 48 hr. CHM given up to 20 min before HN2 reversed the effect of HN2 on DNA synthesis at 2 and 4 hr. A variable protective effect of CHM was observed at 24 and 48 hr. These studies indicate that CHM increases the survival of HN2-treated rats and partially protects rat bone marrow cells from HN2 cytotoxicity.

Liability considerations presented by human gene therapy.

Through the use of a hypothetical scenario, this article examines the legal liability associated with gene therapy. Basic negligence principles are applied to the factual context of a human gene therapy experiment gone awry, including its prior governmental review and its potential effect on future generations. The federal requirements, while not preempting state law damages claims, do provide a mechanism for achieving some protection from liability. The effect on future generations raises questions about the limits of liability.

DNA hybridisation of routinely processed tissue for detecting HPV DNA in anal squamous cell carcinomas over 40 years.

To study possible changes in the incidence of human papillomavirus (HPV) associated anal squamous cell carcinomas (SCC) a simple, rapid, and sensitive technique (alkaline hydrolysis) to permit DNA hybridisation from formalin fixed, paraffin wax embedded tissue was developed. The sensitivity and specificity of the technique were established by comparison with Southern blot analysis and in situ hybridisation on the same tissue specimens. Ninety tissue specimens in a single analysis were examined using this technique. Alkaline hydrolysis was applied to fixed tissue samples which showed a two-fold increase over the past 10 years in the percentage of anal cancers containing HPV type 16 DNA when compared with the previous 30 years using 207 cases of anal cancer collected over a 40 year period. This method has several advantages over the polymerase chain reaction as it is simple, relatively inexpensive, and may be widely applied to the detection and quantification of DNA sequences, including cellular oncogenes.

Is the undeniably palpable liver ever 'normal'?

A study of whether the lower border of the normal liver, if it extended below the costal margin, could be reliably identified by clinical examination was undertaken in 42 patients in whom there was no clinical, biochemical or scintographic evidence of liver disease. Two clinical observers independently agreed that in 10 of these patients the liver extended infracostally. However, scintiscanning demonstrated that 30 patients had livers extending below the costal margin and that 2 of the 10 livers clinically identified did not in fact lie infracostally. Thus whilst the normal liver commonly extended below the costal margin, recognition of this extension by clinical methods occurred no more frequently than would be expected by chance. It is concluded that the confident clinical finding of a liver projecting below the costal margin should suggest that the organ is abnormal.

Nicorandil associated anal ulcers: an estimate of incidence.

INTRODUCTION: Nicorandil is a commonly prescribed antianginal medication that has been found to be associated with painful anal ulceration. The incidence of this complication is unknown. We have used the best data available to us to make an estimate of this figure in a health district with a remarkably stable population of approximately 200,000 people. METHODS: using an electronic search of all letters generated from colorectal and gastroenterology clinics as well as endoscopy reports from January 2004 to November 2010, patients with anal ulceration who were taking nicorandil were identified. Other causes of ulceration were excluded by biopsy in the majority of cases. The central hospital and community pharmacy database was interrogated to estimate the number of patients who were prescribed nicorandil over a six-year period (2004-2010). RESULTS: A total of 30 patients (24 men, 6 women) with a median age of 79.5 years were identified who fulfilled the criteria of: taking nicorandil; having no other identified cause for anal ulceration; and achieving eventual healing after withdrawal of nicorandil. In the six-year period an estimated mean of 1,379 patients were prescribed nicorandil each year. The mean annual incidence of anal ulcers among nicorandil users is therefore calculated to be in the region of 0.37%. CONCLUSIONS: Anal ulceration appears to occur in approximately four in every thousand patients prescribed nicorandil each year. Prescribing physicians should explain the risk of this unpleasant complication to their patients.

Aflatoxin Production by Aspergillus flavus as Related to Various Temperatures.

Two aflatoxin-producing isolates of Aspergillus flavus were grown for 5 days on Wort media at 2, 7, 13, 18, 24, 29, 35, 41, 46, and 52 C. Maximal production of aflatoxins occurred at 24 C. Maximal growth of A. flavus isolates occurred at 29 and 35 C. The ratio of the production of aflatoxin B(1) to aflatoxin G(1) varied with temperature. Aflatoxin production was not related to growth rate of A. flavus; one isolate at 41 C, at almost maximal growth of A. flavus, produced no aflatoxins. At 5 days, no aflatoxins were produced at temperatures lower than 18 C or higher than 35 C. Color of CHCl(3) extracts appeared to be directly correlated with aflatoxin concentrations. A. flavus isolates grown at 2, 7, and 41 C for 12 weeks produced no aflatoxins. At 13 C, both isolates produced aflatoxins in 3 weeks, and one isolate produced increasing amounts with time. The second isolate produced increasing amounts through 6 weeks, but at 12 weeks smaller amounts of aflatoxins were recovered than at 6 weeks.

Marrow culture in diffusion chambers in rabbits. I. Effect of mature granulocytes on cell production.

Factors influencing granulopoiesis have been evaluated using diffusion chambers implanted in the peritoneal cavity of rabbits. An increase in granulopoiesis in chambers implanted in hosts made neutropenic by nitrogen mustard occurs in mice made neutropenic by x-ray or drug. The intraperitoneal injection of leukocytes inhibited the growth of cells in chambers implanted in rabbits. Removal of mature granulocytes from marrow prior to chamber inoculation produced a marked in-increase in cell growth, especially of granulocytes. Mature granulocytes clearly inhibited cell replication and this inhibition involved both myeloid and erythroid elements, although the data suggest a greater effect on myelopoiesis. In contrast to the mouse, erythropoiesis in chambers in rabbits remained prominent for over 1 wk.

Marrow culture in diffusion chambers in rabbits. II. Effect of competing demands for red cell and white cell production on cell growth.

Studies were done of cell production by marrow in diffusion chambers implanted in the peritoneal cavity of rabbits subjected to various stimuli to hematopoiesis. In chambers in neutropenic hosts and in hosts injected with endotoxin, animals presumed to have an increased stimulus to granulopoiesis, there was increased production of granulocytes but there was also increased production of red cells. Although red cell production was decreased in chambers in polycythemic hosts, granulocyte production was not different from that in controls. Stimulation of erythropoiesis by erythropoietin injections or by exposure to hypoxia increased red cell production by marrow in the implanted diffusion chambers without diminishing granulopoiesis. Only in chambers in hosts made anemic by bleeding was there an increase in red cell production accompanied by a decrease in granulocyte production. In these anemic hosts induction of neutropenia led to an increase in granulopoiesis without any depression of erythropoiesis.

Location of parathyroid glands by thallium-technetium subtraction scintigraphy.

In 36 patients with biochemical and clinical evidence of primary or secondary hyperparathyroidism (HPT), preoperative scintigraphic studies were performed with a thallium-technetium subtraction technique. The patients were given 30 MBq technetium pertechnetate and, after a delay of 10-15 minutes, 55 MBq thallium chloride. Data were collected with a gamma camera equipped with a pinhole collimator and dedicated computer. Images were recorded simultaneously in two channels, in order to provide identical positioning for the thallium and technetium images. A standardized gradual computer subtraction was then carried out. Parathyroid adenoma was present in 28 patients, primary parathyroid hyperplasia in two, and secondary hyperplasia due to chronic renal failure in six. The scintigrams located 24 (86%) of the adenomas, but only four (13%) of the total 32 hyperplastic glands. The scintigraphic technique offers considerable advantages in the preoperative location of parathyroid adenomas, which may be of particular interest in persistent or recurrent HPT.

Clinical and pathological correlates of HPV type 16 DNA in anal cancer.

The aetiology of anal squamous cell carcinoma (SCC) has recently been associated with a sexually transmissible agent--human papillomavirus (HPV) type 16. In this study clinical and pathological data from a prospective series of 67 anal SCC collected over a three year period were compared with the HPV type 16 DNA content of these tumours to determine whether any of the clinical or histological parameters might predict HPV DNA content in a tumour specimen. Of twelve clinicopathological variables examined none was significantly correlated with HPV DNA content at the p = 0.01 level.

Anal and cervical intraepithelial neoplasia: possible parallel.

This study evaluated prospectively the use of an endoscope in examination of the anal canal for the detection of premalignant lesions. All patients underwent endoscopy and anal epithelial biopsy; the biopsy samples were examined histologically and human papillomavirus (HPV) DNA hybridisation was done. No evidence of anal intraepithelial neoplasia (AIN) was found in 20 control patients with anal fissure or fistula. Of 82 patients with anal HPV infection, 23 had evidence of AIN. The prevalence of AIN was significantly higher among homosexual than among heterosexual men (17 of 28 vs 1 of 26) with anal HPV infection. Of 28 women with anal HPV infection, 10 had cervical intraepithelial neoplasia (CIN); 5 of the 10 also had AIN, whereas no woman had AIN in the absence of CIN. The study shows that AIN occurs and can be diagnosed endoscopically in a manner similar to CIN. Further detailed prospective studies on the natural history of AIN and of groups at risk are required.

Ki-ras oncogene mutations in non-HPV-associated anal carcinoma.

Human papillomavirus 16 (HPV 16) DNA is found in a high proportion of anal squamous cell carcinomas in whose genesis it is thought to play an important role. In addition, it can be shown to cooperate in vitro with activated ras oncogenes in cellular transformation. We have therefore screened a series of such tumours for activating mutations of the ras oncogene family using DNA amplified in vitro by the polymerase chain reaction (PCR) and a series of synthetic oligonucleotide probes. Mutations were seen in only two cases (both Ki-ras codon 12), neither of which was HPV-associated. Our results suggest that ras activation is not a common event in the genesis of these tumours and, when it does occur, it does not appear to cooperate with HPV.

Anal cancer and human papillomaviruses.

Epidemiologic and clinical evidence has suggested a possible association between anal cancer and human papillomavirus (HPV) types that are known to be associated with cervical and other genital cancers. Using Southern blot and dot blot analysis, the authors examined 45 primary anal malignancies for HPV DNA types 6, 11, 16, and 18. HVP 16, DNA was detected in 23 of 41 (56 percent) anal squamous-cell carcinomas (SCC) and in the lymph-node metastases of two of these tumors. In addition, HPV 18 DNA was detected in 2/41 (5 percent) anal SCCs. Anal SCC contained no detectable HPV 6 or 11 DNA. The remaining four primary anal malignancies were not squamous carcinomas and did not contain any detectable HPV DNA. Nonmalignant anal epithelium and malignant rectal mucosa obtained from surgical patients undergoing hemorrhoidectomy and abdominoperineal excision of the rectum did not contain any detectable HPV DNA. HPV 16 DNA in anal cancer was predominantly integrated into the host cell DNA. In situ hybridization was used to demonstrate that HPV 16 DNA in anal SCC tissues is confined to the nuclei of carcinoma cells. The results of this investigation closely parallel similar studies of cervical cancer and lend support to the concept of the involvement of HPV 16 and 18 in the development of anal and genital squamous-cell carcinoma.